nuclear energy research paper topics

76 Nuclear Energy Essay Topic Ideas & Examples

🏆 best nuclear energy topic ideas & essay examples, 📌 simple & easy nuclear energy essay titles, 👍 good essay topics on nuclear energy.

• Why Nuclear Energy Is Not Good? Even those who say net production is cost effective for unit of nuclear energy produced may not be saying the truth because most of these estimate forget that nuclear energy is recipient of many government […]
• Nuclear Energy Effectiveness Although water is used to cool nuclear plants, we can conclude that nuclear energy is the most cost effective method of producing electricity.
• Metropolitan Edison Company vs. People Against Nuclear Energy In addition, the commission published a hearing notice which entailed an invitation to parties that were interested to submit their briefs explaining the impacts of the accident to the psychological harm or any other indirect […]
• Nuclear Energy: High-Entropy Alloy One of the tools for reducing the level of greenhouse gas emissions is the development of nuclear energy, which is characterized by a high degree of environmental efficiency and the absence of a significant impact […]
• Nuclear Energy: Impact of Science & Technology on Society In spite of the fact that hopes of adherents of the use of atomic energy substantially were not justified, the majority of the governments of the countries of the world do not wish to refuse […]
• Nuclear Energy and The Danger of Environment Nuclear energy can be a benefit in the medium and long term perspective, but the communal and public awareness of nuclear energy breeds anxieties about nuclear technology that must be directed to attain the public […]
• Nuclear Energy: Safe, Economical, Reliable Thus, nuclear energy is viable and safe in meeting the current and future demand for energy across the world. Nuclear energy has significant implications for the environment and population health in case of an accident […]
• Emirates Nuclear Energy Corporation: Business Principles The first 3 are enablers of the system of management while the fourth component is process-oriented, which helps in the development, production, and delivery of services coupled with products of an organization to the market […]
• Nuclear Power as a Primary Energy Source The energy crisis the world faces currently is one of the most urgent and disturbing questions countries have to deal with.
• Nuclear Energy and Its Risks The situation became difficult when the power in the reactors reduced and could not be enough to be used by the operators.
• Fossil Fuel, Nuclear Energy, and Alternative Power Sources It is important to keep in mind that the amount of coal is decreasing and there is no guarantee that people will be able to discover more.
• Emirates Nuclear Energy Corporation’s Employee Training Program The problem is the need to incorporate training and development as part of the human resource management policies of the Emirates Nuclear Energy Corporation.
• Emirates Nuclear Energy Corporation Managerial Accounting The flagship project and the construction of the first reactor of the four scheduled reactors began in 2011. In the execution of the role of management accountants, ENEC encounters challenges due to the use of […]
• Harmful Health Effects of Nuclear Energy The risk of developing thyroid cancer following exposure to nuclear radiations increased with a decrease in the age of the subject.
• Energy Disruption: Causes and Effects of the Fukushima Nuclear Reactors Leak The Fukushima nuclear disaster that occurred in March, 2011in Japan as the result of the earthquake and tsunami led to a number of the serious problems and energy disruption.
• Sustainable Energy Source – Nuclear Energy One of the groups led by World Nuclear Association, believes that nuclear energy is a reliable and efficient source of energy.
• A Cost Benefit Analysis of the Environmental and Economic Effects of Nuclear Energy in the United States The nature of damage posed to the environment depends on the nature of the nuclear plant being used and also the extraction process of fossil fuel themselves.
• Nuclear Energy Fusion and Harnessing Physicists use the equation E=MC2 to calculate the amount of energy that is generated as a result of the fusion of nucleus.
• Nuclear Energy Usage and Recycling The resulting energy is used to power machinery and generate heat for processing purposes. The biggest problem though is that of energy storage, which is considered to be the most crucial requirement for building a […]
• The Effect of Nuclear Energy on the Environment In response to the concerns, this paper proposes the use of thorium reactors to produce nuclear energy because the safety issues of uranium.
• Nuclear Energy Benefits and Demerits The aim of the research is to provide substantial proof that nuclear energy is not efficient and sustainable. It is also argued that the whole process and the impacts of nuclear energy production make the […]
• Balanced Treatment of the Pros and Cons of Nuclear Energy Thus, the use of nuclear power presupposes a number of positive short-term and log-term consequences for the economy of the country and the environment of the planet.
• The Environmental Impact of Nuclear Energy The country has the opportunity to enhance its capacity to generate electricity from nuclear following the approval of the US Nuclear Regulatory Commission to build and operate between three to four units of the Vogtle […]
• Sources of Energy: Nuclear Power and Hydroelectric Power The main source of power in the world is the Sun. The Sun is the sole source of energy that plants use in the process of photosynthesis in order to manufacture their food.
• Corporate Governance Strategy for Emirates Energy Nuclear Corporation To establish the difference privatization will bring to the company in terms of resources and manpower To establish the feasibility of this undertaking in comparison to other companies that manage nuclear transmission such as Exelon […]
• Nuclear Energy in Australia The irony of the matter is that Australia does not use these reserves to produce nuclear energy; two main reasons that has contributed to the un-exploitation are availability of rich coal deposits in the country, […]
• Impact of Nuclear Energy in France Through the process, heat energy is released from the bombardment of the nucleus and the neutrons. The need to manage the nuclear waste affected the economic parameters attached to nuclear energy.
• Nuclear Energy Benefits One of the factors why nuclear energy is an effective source of energy is that it is cost effective. The other factor that makes nuclear energy cost effective is that the risks associated with this […]
• Nuclear Power Provides Cheap and Clean Energy The production of nuclear power is relatively cheap when compared to coal and petroleum. The cost of nuclear fuel for nuclear power generation is much lower compared to coal, oil and gas fired plants.
• Understanding the Significance of Nuclear Energy
• The Nuclear Energy and Its Impact on the Environment and Economic Growth
• The Use of Nuclear Energy as an Alternative to Global Energy Crisis
• The Impact of Nuclear Energy in the Environment and Economic Growth
• The Economic Consequences of Shifting Away From Nuclear Energy
• The Issue of Climate Change and Nuclear Energy
• The Importance of Controlling the Use of Nuclear Energy
• The Environmental Benefits Of Utilizing Nuclear Energy Rather Than Fossil Fuel Energy
• The Problem Of Nuclear Energy
• Understanding How Nuclear Energy Is Produced from the Atom Level
• The Process Of Producing Nuclear Energy From Thorium
• The Dangers of Atomic Weapons and Nuclear Energy
• The Theory of Nuclear Energy and Its Applications in the Industry
• The Tommyknockers and Nuclear Energy
• The Future of the U. S. Nuclear Energy Industry
• The Nuclear Energy Advantage Of The United States
• The Controversy Regarding The Utilization Of Nuclear Energy
• The Future Industry In Energy: Dropping The Concept Of Nuclear Energy
• The Hope For Nuclear Energy As A Source Of Power
• The Role of Nuclear Energy in Our Lives Today
• The Environmental Benefits of Utilizing Nuclear Energy
• The Argument For Nuclear Energy
• The Ethical and Philosophical Implications of Harnessing Nuclear Energy
• The United States Should Use Nuclear Energy
• Why Do We Still Have Nuclear Energy And Fossil Energy
• The Phenomenon Of Decreased Usage Of Nuclear Energy
• The Politics of Nuclear Energy in Western Europe
• The Negative Issues Surrounding the Use of Nuclear Energy as an Alternative Source of Renewable Energy
• Thorium As An Alternative Form Of Nuclear Energy
• The Advantages of Using Nuclear Energy as a Source of Power
• The Complicated, Expensive, and Dangerous Use of Nuclear Energy
• Why European Countries Are Holding Off On Nuclear Energy
• The Socio-Political Economy of Nuclear Energy in China and India
• The Development of Nuclear Energy and It Importance in the World Today
• Should Nuclear Energy Developed Thailand
• Why the United States Should Stop Using Nuclear Energy
• The History, Advancements and Modern Uses of Nuclear Energy
• Transparency and View Regarding Nuclear Energy Before and After the Fukushima Accident: Evidence on Micro-data
• The Hazards in the Coal Mines and the Benefits of Nuclear Energy
• Use Of Nuclear Energy In Modern World
• The Scientific Discoveries on the Nuclear Energy During the 19th Century
• The Pros and Cons When Discussing the Use of Nuclear Energy
• The Potential Benefits and Risks of Using Nuclear Energy to Produce Electricity
• The Manhattan Project Was a Top Secret Nuclear Energy
• The Nuclear Energy Controversy: Finding a Place for the Nuclear Waste
• The Effects Of Nuclear Energy On The Environment
• Pollution Essay Ideas
• Air Pollution Research Ideas
• Experiment Questions
• Technology Essay Ideas
• Global Warming Essay Titles
• Environmental Protection Titles
• Greenhouse Gases Research Ideas
• Environment Research Topics
• Chicago (A-D)
• Chicago (N-B)

IvyPanda. (2023, January 24). 76 Nuclear Energy Essay Topic Ideas & Examples. https://ivypanda.com/essays/topic/nuclear-energy-essay-topics/

"76 Nuclear Energy Essay Topic Ideas & Examples." IvyPanda , 24 Jan. 2023, ivypanda.com/essays/topic/nuclear-energy-essay-topics/.

IvyPanda . (2023) '76 Nuclear Energy Essay Topic Ideas & Examples'. 24 January.

IvyPanda . 2023. "76 Nuclear Energy Essay Topic Ideas & Examples." January 24, 2023. https://ivypanda.com/essays/topic/nuclear-energy-essay-topics/.

1. IvyPanda . "76 Nuclear Energy Essay Topic Ideas & Examples." January 24, 2023. https://ivypanda.com/essays/topic/nuclear-energy-essay-topics/.

Bibliography

IvyPanda . "76 Nuclear Energy Essay Topic Ideas & Examples." January 24, 2023. https://ivypanda.com/essays/topic/nuclear-energy-essay-topics/.

Presentations made painless

• Get Premium

101 Nuclear Energy Essay Topic Ideas & Examples

Inside This Article

Nuclear energy is a controversial topic that sparks debate among scientists, policymakers, and the general public. With the potential for both significant benefits and risks, there is no shortage of essay topics to explore in this field. Whether you are a student looking to write a research paper or an individual interested in learning more about nuclear energy, here are 101 essay topic ideas and examples to get you started:

• The history of nuclear energy development
• The science behind nuclear energy
• The benefits of nuclear energy
• The risks of nuclear energy
• Nuclear energy vs. renewable energy sources
• Nuclear energy and climate change
• Nuclear energy and national security
• The role of nuclear energy in the future energy mix
• Nuclear energy and economic development
• The Fukushima nuclear disaster
• The Chernobyl nuclear disaster
• Nuclear energy and public perception
• Nuclear energy and waste management
• Nuclear energy and nuclear proliferation
• The cost of nuclear energy
• The safety of nuclear power plants
• The role of nuclear energy in reducing carbon emissions
• The ethics of nuclear energy
• Nuclear energy and environmental impact
• The future of nuclear fusion
• The potential of small modular reactors
• The role of nuclear energy in space exploration
• The impact of nuclear energy on wildlife
• Nuclear energy and water usage
• The role of nuclear energy in healthcare (e.g., medical isotopes)
• The social implications of nuclear energy development
• Nuclear energy and energy independence
• The role of nuclear energy in disaster response
• Nuclear energy and the military
• The challenges of decommissioning nuclear power plants
• The role of nuclear energy in developing countries
• Nuclear energy and human health
• The impact of nuclear energy on Indigenous communities
• Nuclear energy and sustainable development
• The role of nuclear energy in addressing energy poverty
• Nuclear energy and the energy transition
• The role of nuclear energy in combating air pollution
• Nuclear energy and job creation
• The impact of nuclear energy on land use
• The role of nuclear energy in achieving energy security
• Nuclear energy and geopolitical considerations
• The impact of nuclear energy on water resources
• The role of nuclear energy in disaster preparedness
• Nuclear energy and social justice
• The role of nuclear energy in urban planning
• The impact of nuclear energy on Indigenous knowledge systems
• Nuclear energy and food security
• The role of nuclear energy in reducing energy poverty
• Nuclear energy and the circular economy
• The impact of nuclear energy on air quality
• The role of nuclear energy in reducing greenhouse gas emissions
• Nuclear energy and energy access
• The challenges of nuclear energy governance
• Nuclear energy and energy justice
• The role of nuclear energy in sustainable development
• Nuclear energy and energy affordability
• The impact of nuclear energy on human rights
• Nuclear energy and energy democracy
• The role of nuclear energy in community development
• Nuclear energy and energy resilience
• The challenges of nuclear energy regulation
• Nuclear energy and energy sovereignty
• The role of nuclear energy in climate adaptation
• Nuclear energy and energy equity
• The impact of nuclear energy on vulnerable populations
• Nuclear energy and energy transition pathways
• The role of nuclear energy in the post-carbon economy
• Nuclear energy and energy infrastructure
• The challenges of nuclear energy policy
• Nuclear energy and energy governance
• The role of nuclear energy in energy sector transformation
• Nuclear energy and energy system integration
• The impact of nuclear energy on energy security
• Nuclear energy and energy sector reform
• The role of nuclear energy in energy planning
• Nuclear energy and energy market dynamics
• The challenges of nuclear energy financing
• Nuclear energy and energy sector regulation
• The role of nuclear energy in energy sector development
• Nuclear energy and energy sector transformation pathways
• The impact of nuclear energy on energy sector sustainability
• Nuclear energy and energy sector resilience
• The role of nuclear energy in energy sector innovation
• Nuclear energy and energy sector disruption
• The challenges of nuclear energy integration
• Nuclear energy and energy sector transition
• The role of nuclear energy in energy sector modernization
• Nuclear energy and energy sector transformation strategies
• The impact of nuclear energy on energy sector competitiveness
• Nuclear energy and energy sector diversification
• The role of nuclear energy in energy sector optimization
• Nuclear energy and energy sector performance
• The challenges of nuclear energy deployment
• Nuclear energy and energy sector transformation initiatives
• The role of nuclear energy in energy sector transformation processes
• Nuclear energy and energy sector transformation trends
• Nuclear energy and energy sector transformation challenges
• The role of nuclear energy in energy sector transformation dynamics
• Nuclear energy and energy sector transformation opportunities
• The challenges of nuclear energy adoption

These essay topic ideas and examples cover a wide range of aspects related to nuclear energy, from its history and science to its benefits and risks. Whether you are interested in exploring the environmental impact of nuclear energy or its role in sustainable development, there is no shortage of topics to delve into. So pick a topic that interests you, conduct thorough research, and start writing your essay on nuclear energy today!

Want to create a presentation now?

Instantly Create A Deck

Let PitchGrade do this for me

Hassle Free

We will create your text and designs for you. Sit back and relax while we do the work.

Explore More Content

• Privacy Policy
• Terms of Service

© 2023 Pitchgrade

Create an account

Create a free IEA account to download our reports or subcribe to a paid service.

Nuclear Power in a Clean Energy System

About this report.

With nuclear power facing an uncertain future in many countries, the world risks a steep decline in its use in advanced economies that could result in billions of tonnes of additional carbon emissions. Some countries have opted out of nuclear power in light of concerns about safety and other issues. Many others, however, still see a role for nuclear in their energy transitions but are not doing enough to meet their goals.

The publication of the IEA's first report addressing nuclear power in nearly two decades brings this important topic back into the global energy debate.

Key findings

Nuclear power is the second-largest source of low-carbon electricity today.

Nuclear power is the second-largest source of low-carbon electricity today, with 452 operating reactors providing 2700 TWh of electricity in 2018, or 10% of global electricity supply.

In advanced economies, nuclear has long been the largest source of low-carbon electricity, providing 18% of supply in 2018. Yet nuclear is quickly losing ground. While 11.2 GW of new nuclear capacity was connected to power grids globally in 2018 – the highest total since 1990 – these additions were concentrated in China and Russia.

Global low-carbon power generation by source, 2018

Cumulative co2 emissions avoided by global nuclear power in selected countries, 1971-2018, an aging nuclear fleet.

In the absense of further lifetime extensions and new projects could result in an additional 4 billion tonnes of CO2 emissions, underlining the importance of the nuclear fleet to low-carbon energy transitions around the globe. In emerging and developing economies, particularly China, the nuclear fleet will provide low-carbon electricity for decades to come.

However the nuclear fleet in advanced economies is 35 years old on average and many plants are nearing the end of their designed lifetimes. Given their age, plants are beginning to close, with 25% of existing nuclear capacity in advanced economies expected to be shut down by 2025.

It is considerably cheaper to extend the life of a reactor than build a new plant, and costs of extensions are competitive with other clean energy options, including new solar PV and wind projects. Nevertheless they still represent a substantial capital investment. The estimated cost of extending the operational life of 1 GW of nuclear capacity for at least 10 years ranges from $500 million to just over $1 billion depending on the condition of the site.

However difficult market conditions are a barrier to lifetime extension investments. An extended period of low wholesale electricity prices in most advanced economies has sharply reduced or eliminated margins for many technologies, putting nuclear at risk of shutting down early if additional investments are needed. As such, the feasibility of extensions depends largely on domestic market conditions.

Age profile of nuclear power capacity in selected regions, 2019

United states, levelised cost of electricity in the united states, 2040, european union, levelised cost of electricity in the european union, 2040, levelised cost of electricity in japan, 2040, the nuclear fade case, nuclear capacity operating in selected advanced economies in the nuclear fade case, 2018-2040, wind and solar pv generation by scenario 2019-2040, policy recommendations.

In this context, countries that intend to retain the option of nuclear power should consider the following actions:

• Keep the option open:  Authorise lifetime extensions of existing nuclear plants for as long as safely possible. 
• Value dispatchability:  Design the electricity market in a way that properly values the system services needed to maintain electricity security, including capacity availability and frequency control services. Make sure that the providers of these services, including nuclear power plants, are compensated in a competitive and non-discriminatory manner.
• Value non-market benefits:  Establish a level playing field for nuclear power with other low-carbon energy sources in recognition of its environmental and energy security benefits and remunerate it accordingly.
• Update safety regulations:  Where necessary, update safety regulations in order to ensure the continued safe operation of nuclear plants. Where technically possible, this should include allowing flexible operation of nuclear power plants to supply ancillary services.
• Create a favourable financing framework:  Create risk management and financing frameworks that facilitate the mobilisation of capital for new and existing plants at an acceptable cost taking the risk profile and long time-horizons of nuclear projects into consideration.
• Support new construction:  Ensure that licensing processes do not lead to project delays and cost increases that are not justified by safety requirements.
• Support innovative new reactor designs:  Accelerate innovation in new reactor designs with lower capital costs and shorter lead times and technologies that improve the operating flexibility of nuclear power plants to facilitate the integration of growing wind and solar capacity into the electricity system.
• Maintain human capital:  Protect and develop the human capital and project management capabilities in nuclear engineering.

Executive summary

Nuclear power can play an important role in clean energy transitions.

Nuclear power today makes a significant contribution to electricity generation, providing 10% of global electricity supply in 2018.  In advanced economies 1 , nuclear power accounts for 18% of generation and is the largest low-carbon source of electricity. However, its share of global electricity supply has been declining in recent years. That has been driven by advanced economies, where nuclear fleets are ageing, additions of new capacity have dwindled to a trickle, and some plants built in the 1970s and 1980s have been retired. This has slowed the transition towards a clean electricity system. Despite the impressive growth of solar and wind power, the overall share of clean energy sources in total electricity supply in 2018, at 36%, was the same as it was 20 years earlier because of the decline in nuclear. Halting that slide will be vital to stepping up the pace of the decarbonisation of electricity supply.

A range of technologies, including nuclear power, will be needed for clean energy transitions around the world.  Global energy is increasingly based around electricity. That means the key to making energy systems clean is to turn the electricity sector from the largest producer of CO 2 emissions into a low-carbon source that reduces fossil fuel emissions in areas like transport, heating and industry. While renewables are expected to continue to lead, nuclear power can also play an important part along with fossil fuels using carbon capture, utilisation and storage. Countries envisaging a future role for nuclear account for the bulk of global energy demand and CO 2 emissions. But to achieve a trajectory consistent with sustainability targets – including international climate goals – the expansion of clean electricity would need to be three times faster than at present. It would require 85% of global electricity to come from clean sources by 2040, compared with just 36% today. Along with massive investments in efficiency and renewables, the trajectory would need an 80% increase in global nuclear power production by 2040.

Nuclear power plants contribute to electricity security in multiple ways.  Nuclear plants help to keep power grids stable. To a certain extent, they can adjust their operations to follow demand and supply shifts. As the share of variable renewables like wind and solar photovoltaics (PV) rises, the need for such services will increase. Nuclear plants can help to limit the impacts from seasonal fluctuations in output from renewables and bolster energy security by reducing dependence on imported fuels.

Lifetime extensions of nuclear power plants are crucial to getting the energy transition back on track

Policy and regulatory decisions remain critical to the fate of ageing reactors in advanced economies.  The average age of their nuclear fleets is 35 years. The European Union and the United States have the largest active nuclear fleets (over 100 gigawatts each), and they are also among the oldest: the average reactor is 35 years old in the European Union and 39 years old in the United States. The original design lifetime for operations was 40 years in most cases. Around one quarter of the current nuclear capacity in advanced economies is set to be shut down by 2025 – mainly because of policies to reduce nuclear’s role. The fate of the remaining capacity depends on decisions about lifetime extensions in the coming years. In the United States, for example, some 90 reactors have 60-year operating licenses, yet several have already been retired early and many more are at risk. In Europe, Japan and other advanced economies, extensions of plants’ lifetimes also face uncertain prospects.

Economic factors are also at play.  Lifetime extensions are considerably cheaper than new construction and are generally cost-competitive with other electricity generation technologies, including new wind and solar projects. However, they still need significant investment to replace and refurbish key components that enable plants to continue operating safely. Low wholesale electricity and carbon prices, together with new regulations on the use of water for cooling reactors, are making some plants in the United States financially unviable. In addition, markets and regulatory systems often penalise nuclear power by not pricing in its value as a clean energy source and its contribution to electricity security. As a result, most nuclear power plants in advanced economies are at risk of closing prematurely.

The hurdles to investment in new nuclear projects in advanced economies are daunting

What happens with plans to build new nuclear plants will significantly affect the chances of achieving clean energy transitions.  Preventing premature decommissioning and enabling longer extensions would reduce the need to ramp up renewables. But without new construction, nuclear power can only provide temporary support for the shift to cleaner energy systems. The biggest barrier to new nuclear construction is mobilising investment.  Plans to build new nuclear plants face concerns about competitiveness with other power generation technologies and the very large size of nuclear projects that require billions of dollars in upfront investment. Those doubts are especially strong in countries that have introduced competitive wholesale markets.

A number of challenges specific to the nature of nuclear power technology may prevent investment from going ahead.  The main obstacles relate to the sheer scale of investment and long lead times; the risk of construction problems, delays and cost overruns; and the possibility of future changes in policy or the electricity system itself. There have been long delays in completing advanced reactors that are still being built in Finland, France and the United States. They have turned out to cost far more than originally expected and dampened investor interest in new projects. For example, Korea has a much better record of completing construction of new projects on time and on budget, although the country plans to reduce its reliance on nuclear power.

Without nuclear investment, achieving a sustainable energy system will be much harder

A collapse in investment in existing and new nuclear plants in advanced economies would have implications for emissions, costs and energy security.  In the case where no further investments are made in advanced economies to extend the operating lifetime of existing nuclear power plants or to develop new projects, nuclear power capacity in those countries would decline by around two-thirds by 2040. Under the current policy ambitions of governments, while renewable investment would continue to grow, gas and, to a lesser extent, coal would play significant roles in replacing nuclear. This would further increase the importance of gas for countries’ electricity security. Cumulative CO 2 emissions would rise by 4 billion tonnes by 2040, adding to the already considerable difficulties of reaching emissions targets. Investment needs would increase by almost USD 340 billion as new power generation capacity and supporting grid infrastructure is built to offset retiring nuclear plants.

Achieving the clean energy transition with less nuclear power is possible but would require an extraordinary effort.  Policy makers and regulators would have to find ways to create the conditions to spur the necessary investment in other clean energy technologies. Advanced economies would face a sizeable shortfall of low-carbon electricity. Wind and solar PV would be the main sources called upon to replace nuclear, and their pace of growth would need to accelerate at an unprecedented rate. Over the past 20 years, wind and solar PV capacity has increased by about 580 GW in advanced economies. But in the next 20 years, nearly five times that much would need to be built to offset nuclear’s decline. For wind and solar PV to achieve that growth, various non-market barriers would need to be overcome such as public and social acceptance of the projects themselves and the associated expansion in network infrastructure. Nuclear power, meanwhile, can contribute to easing the technical difficulties of integrating renewables and lowering the cost of transforming the electricity system.

With nuclear power fading away, electricity systems become less flexible.  Options to offset this include new gas-fired power plants, increased storage (such as pumped storage, batteries or chemical technologies like hydrogen) and demand-side actions (in which consumers are encouraged to shift or lower their consumption in real time in response to price signals). Increasing interconnection with neighbouring systems would also provide additional flexibility, but its effectiveness diminishes when all systems in a region have very high shares of wind and solar PV.

Offsetting less nuclear power with more renewables would cost more

Taking nuclear out of the equation results in higher electricity prices for consumers.  A sharp decline in nuclear in advanced economies would mean a substantial increase in investment needs for other forms of power generation and the electricity network. Around USD 1.6 trillion in additional investment would be required in the electricity sector in advanced economies from 2018 to 2040. Despite recent declines in wind and solar costs, adding new renewable capacity requires considerably more capital investment than extending the lifetimes of existing nuclear reactors. The need to extend the transmission grid to connect new plants and upgrade existing lines to handle the extra power output also increases costs. The additional investment required in advanced economies would not be offset by savings in operational costs, as fuel costs for nuclear power are low, and operation and maintenance make up a minor portion of total electricity supply costs. Without widespread lifetime extensions or new projects, electricity supply costs would be close to USD 80 billion higher per year on average for advanced economies as a whole.

Strong policy support is needed to secure investment in existing and new nuclear plants

Countries that have kept the option of using nuclear power need to reform their policies to ensure competition on a level playing field.  They also need to address barriers to investment in lifetime extensions and new capacity. The focus should be on designing electricity markets in a way that values the clean energy and energy security attributes of low-carbon technologies, including nuclear power.

Securing investment in new nuclear plants would require more intrusive policy intervention given the very high cost of projects and unfavourable recent experiences in some countries.  Investment policies need to overcome financing barriers through a combination of long-term contracts, price guarantees and direct state investment.

Interest is rising in advanced nuclear technologies that suit private investment such as small modular reactors (SMRs).  This technology is still at the development stage. There is a case for governments to promote it through funding for research and development, public-private partnerships for venture capital and early deployment grants. Standardisation of reactor designs would be crucial to benefit from economies of scale in the manufacturing of SMRs.

Continued activity in the operation and development of nuclear technology is required to maintain skills and expertise.  The relatively slow pace of nuclear deployment in advanced economies in recent years means there is a risk of losing human capital and technical know-how. Maintaining human skills and industrial expertise should be a priority for countries that aim to continue relying on nuclear power.

The following recommendations are directed at countries that intend to retain the option of nuclear power. The IEA makes no recommendations to countries that have chosen not to use nuclear power in their clean energy transition and respects their choice to do so.

• Keep the option open:  Authorise lifetime extensions of existing nuclear plants for as long as safely possible.
• Value non-market benefits:  Establish a level playing field for nuclear power with other low carbon energy sources in recognition of its environmental and energy security benefits and remunerate it accordingly.
• Create an attractive financing framework:  Set up risk management and financing frameworks that can help mobilise capital for new and existing plants at an acceptable cost, taking the risk profile and long time horizons of nuclear projects into consideration.
• Support new construction:  Ensure that licensing processes do not lead to project delays and cost increases that are not justified by safety requirements. Support standardisation and enable learning-by-doing across the industry.
• Support innovative new reactor designs:  Accelerate innovation in new reactor designs, such as small modular reactors (SMRs), with lower capital costs and shorter lead times and technologies that improve the operating flexibility of nuclear power plants to facilitate the integration of growing wind and solar capacity into the electricity system.

Advanced economies consist of Australia, Canada, Chile, the 28 members of the European Union, Iceland, Israel, Japan, Korea, Mexico, New Zealand, Norway, Switzerland, Turkey and the United States.

Reference 1

Cite report.

IEA (2019), Nuclear Power in a Clean Energy System , IEA, Paris https://www.iea.org/reports/nuclear-power-in-a-clean-energy-system, Licence: CC BY 4.0

Share this report

• Share on Twitter Twitter
• Share on Facebook Facebook
• Share on LinkedIn LinkedIn
• Share on Email Email
• Share on Print Print

Subscription successful

Thank you for subscribing. You can unsubscribe at any time by clicking the link at the bottom of any IEA newsletter.

• Frontiers in Energy Research
• Nuclear Energy
• Research Topics

Novel Nuclear Reactors and Research Reactors

Total Downloads

Total Views and Downloads

About this Research Topic

With the innovation of nuclear energy technology, Generation IV reactors, small nuclear reactors, and fusion reactors have received widespread attention and research. The Generation IV reactors, such as ultra-high temperature reactors, liquid metal fast reactors, molten salt reactors, etc., have made ...

Keywords : Novel Nuclear Reactors, Research Reactors, Reactor Physics, Thermal-Hydraulics, Reactor Safety, Nuclear Fuel and Materials

Important Note : All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.

Topic Editors

Topic coordinators, recent articles, submission deadlines, participating journals.

Manuscripts can be submitted to this Research Topic via the following journals:

total views

• Demographics

No records found

total views article views downloads topic views

Top countries

Top referring sites, about frontiers research topics.

With their unique mixes of varied contributions from Original Research to Review Articles, Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author.

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

• Publications
• Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

• Advanced Search
• Journal List
• v.45(Suppl 1); 2016 Jan

Nuclear power in the 21st century: Challenges and possibilities

Akos horvath.

MTA Centre for Energy Research, KFKI Campus, P.O.B. 49, Budapest 114, 1525 Hungary

Elisabeth Rachlew

Department of Physics, Royal Institute of Technology, KTH, 10691 Stockholm, Sweden

The current situation and possible future developments for nuclear power—including fission and fusion processes—is presented. The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come. There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors, a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity has been set out in a focussed European programme including the international project of ITER after which a fusion electricity DEMO reactor is envisaged.

Introduction

All countries have a common interest in securing sustainable, low-cost energy supplies with minimal impact on the environment; therefore, many consider nuclear energy as part of their energy mix in fulfilling policy objectives. The discussion of the role of nuclear energy is especially topical for industrialised countries wishing to reduce carbon emissions below the current levels. The latest report from IPCC WGIII ( 2014 ) (see Box 1 for explanations of all acronyms in the article) says: “Nuclear energy is a mature low-GHG emission source of base load power, but its share of global electricity has been declining since 1993. Nuclear energy could make an increasing contribution to low-carbon energy supply, but a variety of barriers and risks exist ”.

Demand for electricity is likely to increase significantly in the future, as current fossil fuel uses are being substituted by processes using electricity. For example, the transport sector is likely to rely increasingly on electricity, whether in the form of fully electric or hybrid vehicles, either using battery power or synthetic hydrocarbon fuels. Here, nuclear power can also contribute, via generation of either electricity or process heat for the production of hydrogen or other fuels.

In Europe, in particular, the public opinion about safety and regulations with nuclear power has introduced much critical discussions about the continuation of nuclear power, and Germany has introduced the “Energiewende” with the goal to close all their nuclear power by 2022. The contribution of nuclear power to the electricity production in the different countries in Europe differs widely with some countries having zero contribution (e.g. Italy, Lithuania) and some with the major part comprising nuclear power (e.g. France, Hungary, Belgium, Slovakia, Sweden).

Current status

The use of nuclear energy for commercial electricity production began in the mid-1950s. In 2013, the world’s 392 GW of installed nuclear capacity accounted for 11 % of electricity generation produced by around 440 nuclear power plants situated in 30 countries (Fig.  1 ). This share has declined gradually since 1996, when it reached almost 18 %, as the rate of new nuclear additions (and generation) has been outpaced by the expansion of other technologies. After hydropower, nuclear is the world’s second-largest source of low-carbon electricity generation (IEA 2014 1 ).

Total number of operating nuclear reactors worldwide. The total number of reactors also include six in Taiwan (source: IAEA 2015) ( https://www.iaea.org/newscenter/focus/nuclear-power )

The Country Nuclear Power Profiles (CNPP 2 ) compiles background information on the status and development of nuclear power programmes in member states. The CNPP’s main objectives are to consolidate information about the nuclear power infrastructures in participating countries, and to present factors related to the effective planning, decision-making and implementation of nuclear power programmes that together lead to safe and economical operations of nuclear power plants.

Within the European Union, 27 % of electricity production (13 % of primary energy) is obtained from 132 nuclear power plants in January 2015 (Fig.  1 ). Across the world, 65 new reactors are under construction, mainly in Asia (China, South Korea, India), and also in Russia, Slovakia, France and Finland. Many other new reactors are in the planning stage, including for example, 12 in the UK.

Apart from one first Generation “Magnox” reactor still operating in the UK, the remainder of the operating fleet is of the second or third Generation type (Fig.  2 ). The predominant technology is the Light Water Reactor (LWR) developed originally in the United States by Westinghouse and then exploited massively by France and others in the 1970s as a response to the 1973 oil crisis. The UK followed a different path and pursued the Advanced Gas-cooled Reactor (AGR). Some countries (France, UK, Russia, Japan) built demonstration scale fast neutron reactors in the 1960s and 70s, but the only commercial reactor of this type currently operating is in Russia.

Nuclear reactor generations from the pioneering age to the next decade (reproduced with permission from Ricotti 2013 )

Future evolution

The fourth Generation reactors, offering the potential of much higher energy recovery and reduced volumes of radioactive waste, are under study in the framework of the “Generation IV International Forum” (GIF) 3 and the “International Project on Innovative Nuclear Reactors and Fuel Cycles” (INPRO). The European Commission in 2010 launched the European Sustainable Nuclear Industrial Initiative (ESNII), which will support three Generation IV fast reactor projects as part of the EU’s plan to promote low-carbon energy technologies. Other initiatives supporting biomass, wind, solar, electricity grids and carbon sequestration are in parallel. ESNII will take forward: the Astrid sodium-cooled fast reactor (SFR) proposed by France, the Allegro gas-cooled fast reactor (GFR) supported by central and eastern Europe and the MYRRHA lead- cooled fast reactor (LFR) technology pilot proposed by Belgium.

The generation of nuclear energy from uranium produces not only electricity but also spent fuel and high-level radioactive waste (HLW) as a by-product. For this HLW, a technical and socially acceptable solution is necessary. The time scale needed for the radiotoxicity of the spent fuel to drop to the level of natural uranium is very long (i.e. of the order of 200 000–300 000 years). The preferred solution for disposing of spent fuel or the HLW resulting from classical reprocessing is deep geological storage. Whilst there are no such geological repositories operating yet in the world, Sweden, Finland and France are on track to have such facilities ready by 2025 (Kautsky et al. 2013 ). In this context it should also be mentioned that it is only for a minor fraction of the HLW that recycling and transmutation is required since adequate separation techniques of the fuel can be recycled and again fed through the LWR system.

The “Strategic Energy Technology Plan” (SET-Plan) identifies fission energy as one of the contributors to the 2050 objectives of a low-carbon energy mix, relying on the Generation-3 reactors, closed fuel cycle and the start of implementation of Generation IV reactors making nuclear energy more sustainable. The EU Energy Roadmap 2050 provides decarbonisation scenarios with different assumptions from the nuclear perspective: two scenarios contemplate a nuclear phase-out by 2050, whilst three others consider that 15–20 % of electricity will be produced by nuclear energy. If by 2050 a generation capacity of 20 % nuclear electricity (140 GWe) is to be secured, 100–120 nuclear power units will have to be built between now and 2050, the precise number depending on the power rating (Garbil and Goethem 2013 ).

Despite the regional differences in the development plans, the main questions are of common interest to all countries, and require solutions in order to maintain nuclear power in the power mix of contributing to sustainable economic growth. The questions include (i) maintaining safe operation of the nuclear plants, (ii) securing the fuel supplies, (iii) a strategy for the management of radioactive waste and spent nuclear fuel.

Safety and non-proliferation risks are managed in accordance with the international rules issued both by IAEA and EURATOM in the EU. The nuclear countries have signed the corresponding agreements and the majority of them have created the necessary legal and regulatory structure (Nuclear Safety Authority). As regards radioactive wastes, particularly high-level wastes (HLW) and spent fuel (SF) most of the countries have long-term policies. The establishment of new nuclear units and the associated nuclear technology developments offer new perspectives, which may need reconsideration of fuel cycle policies and more active regional and global co-operation.

Open and closed fuel cycle

In the frame of the open fuel cycle, the spent fuel will be taken to final disposal without recycling. Deep geological repositories are the only available option for isolating the highly radioactive materials for a very long time from the biosphere. Long-term (80–100 years) near soil intermediate storages are realised in e.g. France and the Netherlands which will allow for permanent access and inspection. The main advantage of the open fuel cycle is its simplicity. The spent fuel assemblies are first stored in interim storage for several years or decades, then they will be placed in special containers and moved into deep underground storage facilities. The technology for producing such containers and for excavation of the underground system of tunnels exists today (Hózer et al. 2010 ; Kautsky et al. 2013 ).

The European Academies Science Advisory Board recently released the report on “Management of spent nuclear fuel and its waste” (EASAC 2014 ). The report discusses the challenges associated with different strategies to manage spent nuclear fuel, in respect of both open cycles and steps towards closing the nuclear fuel cycle. It integrates the conclusions on the issues raised on sustainability, safety, non-proliferation and security, economics, public involvement and on the decision-making process. Recently Vandenbosch et al. ( 2015 ) critically discussed the issue of confidence in the indefinite storage of nuclear waste. One complication of the nuclear waste storage problem is that the minor actinides represent a high activity (see Fig.  3 ) and pose non-proliferation issues to be handled safely in a civil used plant. This might be a difficult challenge if the storage is to be operated economically together with the fuel fabrication.

Radiotoxicity of radioactive waste

The open (or ‘once through’) cycle only uses part of the energy stored in the fuel, whilst effectively wasting substantial amounts of energy that could be recovered through recycling. The conventional closed fuel cycle strategy uses the reprocessing of the spent fuel following interim storage. The main components which can be further utilised (U and Pu) are recycled to fuel manufacturing (MOX (Mixed Oxide) fuel fabrication), whilst the smaller volume of residual waste in appropriately conditioned form—e.g. vitrified and encapsulated—is disposed of in deep geological repositories.

The advanced closed fuel cycle strategy is similar to the conventional one, but within this strategy the minor actinides are also removed during reprocessing. The separated isotopes are transmuted in combination with power generation and only the net reprocessing wastes and those conditioned wastes generated during transmutation will be, following appropriate encapsulation, disposed of in deep geological repositories. The main factor that determines the overall storage capacity of a long-term repository is the heat content of nuclear waste, not its volume. During the anticipated repository time, the specific heat generated during the decay of the stored HLW must always stay below a dedicated value prescribed by the storage concept and the geological host information. The waste that results from reprocessing spent fuel from thermal reactors has a lower heat content (after a period of cooling) than does the spent fuel itself. Thus, it can be stored more densely.

A modern light water reactor of 1 GWe capacity will typically discharge about 20–25 tonnes of irradiated fuel per year of operation. About 93–94 % of the mass of typical uranium oxide irradiated fuel comprises uranium (mostly 238 U), with about 4–5 % fission products and ~1 % plutonium. About 0.1–0.2 % of the mass comprises minor actinides (neptunium, americium and curium). These latter elements accumulate in nuclear fuel because of neutron capture, and they contribute significantly to decay heat loading and neutron output, as well as to the overall radiotoxic hazard of spent fuel. Although the total minor actinide mass is relatively small—20 to 25 kg per year from a 1 GWe LWR—it has a disproportionate impact on spent fuel disposal because of its long radioactive decay times (OECD Nuclear Energy Agency 2013 ).

Generation IV development

To address the issue of sustainability of nuclear energy, in particular the use of natural resources, fast neutron reactors (FNRs) must be developed, since they can typically multiply by over a factor 50 the energy production from a given amount of uranium fuel compared to current reactors. FNRs, just as today’s fleet, will be primarily dedicated to the generation of fossil-free base-load electricity. In the FNR the fuel conversion ratio (FCR) is optimised. Through hardening the spectrum a fast reactor can be designed to burn minor actinides giving a FCR larger than unity which allows breeding of fissile materials. FNRs have been operated in the past (especially the Sodium-cooled Fast Reactor in Europe), but today’s safety, operational and competitiveness standards require the design of a new generation of fast reactors. Important research and development is currently being coordinated at the international level through initiatives such as GIF.

In 2002, six reactor technologies were selected which GIF believe represent the future of nuclear energy. These were selected from the many various approaches being studied on the basis of being clean, safe and cost-effective means of meeting increased energy demands on a sustainable basis. Furthermore, they are considered being resistant to diversion of materials for weapons proliferation and secure from terrorist attacks. The continued research and development will focus on the chosen six reactor approaches. Most of the six systems employ a closed fuel cycle to maximise the resource base and minimise high-level wastes to be sent to a repository. Three of the six are fast neutron reactors (FNR) and one can be built as a fast reactor, one is described as epithermal, and only two operate with slow neutrons like today’s plants. Only one is cooled by light water, two are helium-cooled and the others have lead–bismuth, sodium or fluoride salt coolant. The latter three operate at low pressure, with significant safety advantage. The last has the uranium fuel dissolved in the circulating coolant. Temperatures range from 510 to 1000 °C, compared with less than 330 °C for today’s light water reactors, and this means that four of them can be used for thermochemical hydrogen production.

The sizes range from 150 to 1500 MWe, with the lead-cooled one optionally available as a 50–150 MWe “battery” with long core life (15–20 years without refuelling) as replaceable cassette or entire reactor module. This is designed for distributed generation or desalination. At least four of the systems have significant operating experience already in most respects of their design, which provides a good basis for further research and development and is likely to mean that they can be in commercial operation well before 2030. However, when addressing non-proliferation concerns it is significant that fast neutron reactors are not conventional fast breeders, i.e. they do not have a blanket assembly where plutonium-239 is produced. Instead, plutonium production happens to take place in the core, where burn-up is high and the proportion of plutonium isotopes other than Pu-239 remains high. In addition, new reprocessing technologies will enable the fuel to be recycled without separating the plutonium.

In January 2014, a new GIF Technology Roadmap Update was published. 4 It confirmed the choice of the six systems and focused on the most relevant developments of them so as to define the research and development goals for the next decade. It suggested that the Generation IV technologies most likely to be deployed first are the SFR, the lead-cooled fast reactor (LFR) and the very high temperature reactor technologies. The molten salt reactor and the GFR were shown as furthest from demonstration phase.

Europe, through sustainable nuclear energy technology platform (SNETP) and ESNII, has defined its own strategy and priorities for FNRs with the goal to demonstrate Generation IV reactor technologies that can close the nuclear fuel cycle, provide long-term waste management solutions and expand the applications of nuclear fission beyond electricity production to hydrogen production, industrial heat and desalination; The SFR as a proven concept, as well as the LFR as a short-medium term alternative and the GFR as a longer-term alternative technology. The French Commissariat à l’Energie Atomique (CEA) has chosen the development of the SFR technology. Astrid (Advanced Sodium Technological Reactor for Industrial Demonstration) is based on about 45 reactor-years of operational experience in France and will be rated 250 to 600 MWe. It is expected to be built at Marcoule from 2017, with the unit being connected to the grid in 2022.

Other countries like Belgium, Italy, Sweden and Romania are focussing their research and development effort on the LFR whereas Hungary, Czech Republic and Slovakia are investing in the research and development on GFR building upon the work initiated in France on GFR as an alternative technology to SFR. Allegro GFR is to be built in eastern Europe, and is more innovative. It is rated at 100 MWt and would lead to a larger industrial demonstration unit called GoFastR. The Czech Republic, Hungary and Slovakia are making a joint proposal to host the project, with French CEA support. Allegro is expected to begin construction in 2018 operate from 2025. The industrial demonstrator would follow it.

In mid-2013, four nuclear research institutes and engineering companies from central Europe’s Visegrád Group of Nations (V4) agreed to establish a centre for joint research, development and innovation in Generation IV nuclear reactors (the Czech Republic, Hungary, Poland and Slovakia) which is focused on gas-cooled fast reactors such as Allegro.

The MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) 5 project proposed in Belgium by SCK•CEN could be an Experimental Technological Pilot Plant (ETPP) for the LFR technology. Later, it could become a European fast neutron technology pilot plant for lead and a multi-purpose research reactor. The unit is rated at 100 thermal MW and has started construction at SCK-CEN’s Mol site in 2014 planned to begin operation in 2023. A reduced-power model of Myrrha called Guinevere started up at Mol in March 2010. ESNII also includes an LFR technology demonstrator known as Alfred, also about 100 MWt, seen as a prelude to an industrial demonstration unit of about 600 MWe. Construction on Alfred could begin in 2017 and the unit could start operating in 2025.

Research and development topics to meet the top-level criteria established within the GIF forum in the context of simultaneously matching economics as well as stricter safety criteria set-up by the WENRA FNR demand substantial improvements with respect to the following issues:

• Primary system design simplification,
• Improved materials,
• Innovative heat exchangers and power conversion systems,
• Advanced instrumentation, in-service inspection systems,
• Enhanced safety,

and those for fuel cycle issues pertain to:

• Partitioning and transmutation,
• Innovative fuels (including minor actinide-bearing) and core performance,
• Advanced separation both via aqueous processes supplementing the PUREX process as well as pyroprocessing, which is mandatory for the reprocessing of the high MA-containing fuels,
• Develop a final depository.

Beyond the research and development, the demonstration projects mentioned above are planned in the frame of the SET-Plan ESNII for sustainable fission. In addition, supporting research infrastructures, irradiation facilities, experimental loops and fuel fabrication facilities, will need to be constructed.

Regarding transmutation, the accelerator-driven transmutation systems (ADS) technology must be compared to FNR technology from the point of view of feasibility, transmutation efficiency and cost efficiency. It is the objective of the MYRRHA project to be an experimental demonstrator of ADS technology. From the economical point of view, the ADS industrial solution should be assessed in terms of its contribution to closing the fuel cycle. One point of utmost importance for the ADS is its ability for burning larger amounts of minor actinides (the typical maximum in a critical FNR is about 2 %).

The concept of partitioning and transmutation (P&T) has three main goals: reduce the radiological hazard associated with spent fuel by reducing the inventory of minor actinides, reduce the time interval required to reach the radiotoxicity of natural uranium and reduce the heat load of the HLW packages to be stored in the geological disposal hence reducing the foot print of the geological disposal.

Advanced management of HLW through P&T consists in advanced separation of the minor actinides (americium, curium and neptunium) and some fission products with a long half-life present in the nuclear waste and their transmutation in dedicated burners to reduce the radiological and heat loads on the geological disposal. The time scale needed for the radiotoxicity of the waste to drop to the level of natural uranium will be reduced from a ‘geological’ value (300 000 years) to a value that is comparable to that of human activities (few hundreds of years) (OECD/NEA 2006 ; OECD 2012 ; PATEROS 2008 6 ). Transmutation of the minor actinides is achieved through fission reactions and therefore fast neutrons are preferred in dedicated burners.

At the European level, four building blocks strategy for Partitioning and Transmutation have been identified. Each block poses a serious challenge in terms of research & development to be done in order to reach industrial scale deployment. These blocks are:

• Demonstration of advanced reprocessing of spent nuclear fuel from LWRs, separating Uranium, Plutonium and Minor Actinides;
• Demonstration of the capability to fabricate at semi-industrial level dedicated transmuter fuel heavily loaded in minor actinides;
• Design and construct one or more dedicated transmuters;
• Fabrication of new transmuter fuel together with demonstration of advanced reprocessing of transmuter fuel.

MYRRHA will support this Roadmap by playing the role of an ADS prototype (at reasonable power level) and as a flexible irradiation facility providing fast neutrons for the qualification of materials and fuel for an industrial transmuter. MYRRHA will be not only capable of irradiating samples of such inert matrix fuels but also of housing fuel pins or even a limited number of fuel assemblies heavily loaded with MAs for irradiation and qualification purposes.

Options for nuclear fusion beyond 2050

Nuclear fusion research, on the basis of magnetic confinement, considered in this report, has been actively pursued in Europe from the mid-60s. Fusion research has the goal to achieve a clean and sustainable energy source for many generations to come. In parallel with basic high-temperature plasma research, the fusion technology programme is pursued as well as the economy of a future fusion reactor (Ward et al. 2005 ; Ward 2009 ; Bradshaw et al. 2011 ). The goal-oriented fusion research should be driven with an increased effort to be able to give the long searched answer to the open question, “will fusion energy be able to cover a major part of mankind’s electricity demand?”. ITER, the first fusion reactor to be built in France by the seven collaborating partners (Europe, USA, Russia, Japan, Korea, China, India) is hoped to answer most of the open physics and many of the remaining technology/material questions. ITER is expected to start operation of the first plasma around 2020 and D-T operation 2027.

The European fusion research has been successful through the organisation of EURATOM to which most countries in Europe belong (the fission programme is also included in EURATOM). EUROfusion, the European Consortium for the Development of Fusion Energy, manages European fusion research activities on behalf of EURATOM. The organisation of the research has resulted in a well-focused common fusion research programme. The members of the EUROfusion 7 consortium are 29 national fusion laboratories. EUROfusion funds all fusion research activities in accordance with the “EFDA Fusion electricity. Roadmap to the realisation of fusion energy” (EFDA 2012 , Fusion electricity). The Roadmap outlines the most efficient way to realise fusion electricity. It is the result of an analysis of the European Fusion Programme undertaken by all Research Units within EUROfusion’s predecessor agreement, the European Fusion Development Agreement, EFDA.

The most successful confinement concepts are toroidal ones like tokamaks and helical systems like stellarators (Wagner 2012 , 2013 ). To avoid drift losses, two magnetic field components are necessary for confinement and stability—the toroidal and the poloidal field component. Due to their superposition, the magnetic field winds helically around a system of nested toroids. In both cases, tokamak and stellarator, the toroidal field is produced by external coils; the poloidal field arises from a strong toroidal plasma current in tokamaks. In case of helical systems all necessary fields are produced externally by coils which have to be superconductive when steady-state operation is intended. Europe is constructing the most ambitious stellarator, Wendelstein 7-X in Germany. It is a fully optimised system with promising features. W7-X goes into operation in 2015. 8

Fusion research has now reached plasma parameters needed for a fusion reactor, even if not all parameters are reached simultaneously in a single plasma discharge (see Fig.  4 ). Plotted is the triple product n•τ E• T i composed of the density n, the confinement time τ E and the ion temperature T i . For ignition of a deuterium–tritium plasma, when the internal α-particle heating from the DT-reaction takes over and allows the external heating to be switched off, the triple product has to be about >6 × 10 21  m −3  s keV). The record parameters given as of today are shown together with the fusion experiment of its achievement in Fig.  4 . The achieved parameters and the missing factors to the ultimate goal of a fusion reactor are summarised below:

• Temperature: 40 keV achieved (JT-60U, Japan); the goal is surpassed by a factor of two
• Density n surpassed by factor 5 (C-mod,USA; LHD,Japan)
• Energy confinement time: a factor of 4 is missing (JET, Europe)
• Fusion triple product (see Fig.  4 : a factor of 6 is missing (JET, Europe)
• The first scientific goal is achieved: Q (fusion power/external heating power) ~1 (0,65) (JET, Europe)
• D-T operation without problems (TFTR (USA), JET, small tritium quantities have been used, however)
• Maximal fusion power for short pulse: 16 MW (JET)
• Divertor development (ASDEX, ASDEX-Upgrade, Germany)
• Design for the first experimental reactor complete (ITER, see below)
• The optimisation of stellarators (W7-AS, W7-X, Germany)

Progress in fusion parameters. Derived in 1955, the Lawson criterion specifies the conditions that must be met for fusion to produce a net energy output (1 keV × 12 million K). From this, a fusion “triple product” can be derived, which is defined as the product of the plasma ion density, ion temperature and energy confinement time. This product must be greater than about 6 × 10 21  keV m −3  s for a deuterium–tritium plasma to ignite. Due to the radioactivity associated with tritium, today’s research tokamaks generally operate with deuterium only ( solid dots ). The large tokamaks JET(EU) and TFTR(US), however, have used a deuterium–tritium mix ( open dots ). The rate of increase in tokamak performance has outstripped that of Moore’s law for the miniaturisation of silicon chips (Pitts et al. 2006 ). Many international projects (their names are given by acronyms in the figure) have contributed to the development of fusion plasma parameters and the progress in fusion research which serves as the basis for the ITER design

After 50 years of fusion research there is no evidence for a fundamental obstacle in the basic physics. But still many problems have to be overcome as detailed below:

Critical issues in fusion plasma physics based on magnetic confinement

• confine a plasma magnetically with 1000 m 3 volume,
• maintain the plasma stable at 2–4 bar pressure,
• achieve 15 MA current running in a fluid (in case of tokamaks, avoid instabilities leading to disruptions),
• find methods to maintain the plasma current in steady-state,
• tame plasma turbulence to get the necessary confinement time,
• develop an exhaust system (divertor) to control power and particle exhaust, specifically to remove the α-particle heat deposited into the plasma and to control He as the fusion ash.

Critical issues in fusion plasma technology

• build a system with 200 MKelvin in the plasma core and 4 Kelvin about 2 m away,
• build magnetic system at 6 Tesla (max field 12 Tesla) with 50 GJ energy,
• develop heating systems to heat the plasma to the fusion temperature and current drive systems to maintain steady-state conditions for the tokamak,
• handle neutron-fluxes of 2 MW/m 2 leading to 100 dpa in the surrounding material,
• develop low activation materials,
• develop tritium breeding technologies,
• provide high availability of a complex system using an appropriate remote handling system,
• develop the complete physics and engineering basis for system licensing.

The goals of ITER

The major goals of ITER (see Fig.  5 ) in physics are to confine a D-T plasma with α-particle self-heating dominating all other forms of plasma heating, to produce about ~500 MW of fusion power at a gain Q  = fusion power/external heating power, of about 10, to explore plasma stability in the presence of energetic α-particles, and to demonstrate ash-exhaust and burn control.

Schematic layout of the ITER reactor experiment (from www.iter.org )

In the field of technology, ITER will demonstrate fundamental aspects of fusion as the self-heating of the plasma by alpha-particles, show the essentials to a fusion reactor in an integrated system, give the first test a breeding blanket and assess the technology and its efficiency, breed tritium from lithium utilising the D-T fusion neutron, develop scenarios and materials with low T-inventories. Thus ITER will provide strong indications for vital research and development efforts necessary in the view of a demonstration reactor (DEMO). ITER will be based on conventional steel as structural material. Its inner wall will be covered with beryllium to surround the plasma with low-Z metal with low inventory properties. The divertor will be mostly from tungsten to sustain the high α-particle heat fluxes directed onto target plates situated inside a divertor chamber. An important step in fusion reactor development is the achievement of licensing of the complete system.

The rewards from fusion research and the realisation of a fusion reactor can be described in the following points:

• fusion has a tremendous potential thanks to the availability of deuterium and lithium as primary fuels. But as a recommendation, the fusion development has to be accelerated,

Fusion time strategy towards the fusion reactor on the net (EFDA 2012 , Fusion electricity. A roadmap to the realisation of fusion energy)

In addition, there is the fusion technology programme and its material branch, which ultimately need a neutron source to study the interaction with 14 MeV neutrons. For this purpose, a spallation source IFMIF is presently under design. As a recommendation, ways have to be found to accelerate the fusion development. In general, with ITER, IFMIF and the DEMO, the programme will move away from plasma science more towards technology orientation. After the ITER physics and technology programme—if successful—fusion can be placed into national energy supply strategies. With fusion, future generations can have access to a clean, safe and (at least expected of today) economic power source.

The fission nuclear power continues to be an essential part of the low-carbon electricity generation in the world for decades to come. There are breakthrough possibilities in the development of new generation nuclear reactors where the life-time of the nuclear waste can be reduced to some hundreds of years instead of the present time-scales of hundred thousand of years. Research on the fourth generation reactors is needed for the realisation of this development. For the fast nuclear reactors a substantial research and development effort is required in many fields—from material sciences to safety demonstration—to attain the envisaged goals. Fusion provides a long-term vision for an efficient energy production. The fusion option for a nuclear reactor for efficient production of electricity should be vigorously pursued on the international arena as well as within the European energy roadmap to reach a decision point which allows to critically assess this energy option.

Box 1 Explanations of abbreviations used in this article

Biographies.

is Professor in Energy Research and Director of MTA Center for Energy Research, Budapest, Hungary. His research interests are in the development of new fission reactors, new structural materials, high temperature irradiation resistance, mechanical deformation.

is Professor of Applied Atomic and Molecular Physics at Royal Institute of Technology, (KTH), Stockholm, Sweden. Her research interests are in basic atomic and molecular processes studied with synchrotron radiation, development of diagnostic techniques for analysing the performance of fusion experiments in particular development of photon spectroscopic diagnostics.

1 http://www.iea.org/ .

2 https://cnpp.iaea.org/pages/index.htm .

3 GenIV International forum: ( http://www.gen-4.org/index.html ).

4 https://www.gen-4.org/gif/jcms/c_60729/technology-roadmap-update-2013 .

5 http://myrrha.sckcen.be/ .

6 www.sckcen.be/pateros/ .

7 https://www.euro-fusion.org/ .

8 https://www.ipp.mpg.de/ippcms/de/pr/forschung/w7x/index.html .

Contributor Information

Akos Horvath, Email: [email protected] .

Elisabeth Rachlew, Email: es.htk@kre .

• Bradshaw AM, Hamacher T, Fischer U. Is nuclear fusion a sustainable energy form? Fusion Engineering and Design. 2011; 86 :2770–2773. doi: 10.1016/j.fusengdes.2010.11.040. [ CrossRef ] [ Google Scholar ]
• EASAC. 2014. EASAC Report 23—Management of spent nuclear fuel and its waste. http://www.easac.eu/energy/reports-and-statements/detail-view/article/management-o.html .
• EFDA. 2012. Fusion electricity. A roadmap to the realization of fusion energy. https://www.euro-fusion.org/wpcms/wp-content/uploads/2013/01/JG12.356-web.pdf .
• Garbil, R., and G. Van Goethem. (ed.). 2013. Symposium on the “Benefits and limitations of nuclear fission for a low carbon economy”, European Commission, Brussels, ISBN 978-92.79.29833.2.
• Hózer, Z. S. Borovitskiy, G. Buday, B. Boullis, G. Cognet, S. A. Delichatsios, J. Gadó, A. Grishin, et al. 2010. Regional strategies concerning nuclear fuel cycle and HLRW in Central and Eastern European Countries. International conference on management of spent fuel from Nuclear Power Reactors, Vienna, Conference ID:38089 (CN-178).
• IEA (International Energy Authority). 2014. World Energy Outlook 2014. http://www.iea.org/ .
• IPCC. 2014. Summary for policymakers WGIII AR5, SPM.4.2.2 Energy supply.
• Kautsky, U., T. Lindborg, and J. Valentin (ed.). 2013. Humans and ecosystems over the coming millenia: A biosphere assessment of radioactive waste disposal in Sweden. Ambio 42(4): 381–526. [ PMC free article ] [ PubMed ]
• OECD. 2011–2012. Fact book: Economic, environmental and social statistics. Retrieved from http://www.oecd-ilibrary.org/economics/oecd-factbook-2011-2012_factbook-2011-en .
• OECD/NEA. 2006. Potential benefits and impacts of advanced nuclear fuel cycles with actinide partitioning and transmutation. ISBN: 978-92-64-99165-1, http://www.oecd-nea.org/science/reports/2011/6894-benefits-impacts-advanced-fuel.pdf .
• OECD Nuclear Energy Agency. 2013. Minor actinide burning in thermal reactors. A report by the Working Party on Scientific Issues of Reactor Systems, NEA #6997. http://www.oecd-nea.org/science/pubs/2013/6997-minor-actinide.pdf .
• Pitts R, Buttery R, Pinches S. Fusion: The way ahead. Physics World. 2006; 19 :20–26. doi: 10.1088/2058-7058/19/3/35. [ CrossRef ] [ Google Scholar ]
• Ricotti ME. Nuclear energy: Basics, present, future. EPJ Web of Conferences. 2013; 54 :01005. doi: 10.1051/epjconf/20135401005. [ CrossRef ] [ Google Scholar ]
• Vandenbosch R, Vandenbosch SE. Nuclear waste confidence: Is indefinite storage safe? APS Physics and Society. 2015; 44 :5–7. [ Google Scholar ]
• Wagner, F. 2012. Fusion energy by magnetic confinement. IPP 18/3, http://hdl.handle.net/11858/00-001M-0000-0026-E767-A .
• Wagner F. Physics of magnetic confinement fusion. EPJ Web of Conferences. 2013; 54 :01007. doi: 10.1051/epjconf/20135401007. [ CrossRef ] [ Google Scholar ]
• Ward DJ. The contribution of fusion to sustainable development. Fusion Engineering and Design. 2009; 82 :528–533. doi: 10.1016/j.fusengdes.2007.02.028. [ CrossRef ] [ Google Scholar ]
• Ward DJ, Cook I, Lechon Y, Saez R. The economic viability of fusion power. Engineering and Design. 2005; 75–79 :1221–1227. doi: 10.1016/j.fusengdes.2005.06.160. [ CrossRef ] [ Google Scholar ]

Nuclear Energy

Nuclear energy is the energy in the nucleus, or core, of an atom. Nuclear energy can be used to create electricity, but it must first be released from the atom.

Engineering, Physics

Loading ...

Nuclear energy is the energy in the nucleus , or core, of an atom . Atoms are tiny units that make up all matter in the universe , and energy is what holds the nucleus together. There is a huge amount of energy in an atom 's dense nucleus . In fact, the power that holds the nucleus together is officially called the " strong force ." Nuclear energy can be used to create electricity , but it must first be released from the atom . In the process of  nuclear fission , atoms are split to release that energy. A nuclear reactor , or power plant , is a series of machines that can control nuclear fission to produce electricity . The fuel that nuclear reactors use to produce nuclear fission is pellets of the element uranium . In a nuclear reactor , atoms of uranium are forced to break apart. As they split, the atoms release tiny particles called fission products. Fission products cause other uranium atoms to split, starting a chain reaction . The energy released from this chain reaction creates heat. The heat created by nuclear fission warms the reactor's cooling agent . A cooling agent is usually water, but some nuclear reactors use liquid metal or molten salt . The cooling agent , heated by nuclear fission , produces steam . The steam turns turbines , or wheels turned by a flowing current . The turbines drive generators , or engines that create electricity . Rods of material called nuclear poison can adjust how much electricity is produced. Nuclear poisons are materials, such as a type of the element xenon , that absorb some of the fission products created by nuclear fission . The more rods of nuclear poison that are present during the chain reaction , the slower and more controlled the reaction will be. Removing the rods will allow a stronger chain reaction and create more electricity . As of 2011, about 15 percent of the world's electricity is generated by nuclear power plants . The United States has more than 100 reactors, although it creates most of its electricity from fossil fuels and hydroelectric energy . Nations such as Lithuania, France, and Slovakia create almost all of their electricity from nuclear power plants . Nuclear Food: Uranium Uranium is the fuel most widely used to produce nuclear energy . That's because uranium atoms split apart relatively easily. Uranium is also a very common element, found in rocks all over the world. However, the specific type of uranium used to produce nuclear energy , called U-235 , is rare. U-235 makes up less than one percent of the uranium in the world.

Although some of the uranium the United States uses is mined in this country, most is imported . The U.S. gets uranium from Australia, Canada, Kazakhstan, Russia, and Uzbekistan. Once uranium is mined, it must be extracted from other minerals . It must also be processed before it can be used. Because nuclear fuel can be used to create nuclear weapons as well as nuclear reactors , only nations that are part of the Nuclear Non-Proliferation Treaty (NPT) are allowed to import uranium or plutonium , another nuclear fuel . The treaty promotes the peaceful use of nuclear fuel , as well as limiting the spread of nuclear weapons . A typical nuclear reactor uses about 200 tons of uranium every year. Complex processes allow some uranium and plutonium to be re-enriched or recycled . This reduces the amount of mining , extracting , and processing that needs to be done. Nuclear Energy and People Nuclear energy produces electricity that can be used to power homes, schools, businesses, and hospitals. The first nuclear reactor to produce electricity was located near Arco, Idaho. The Experimental Breeder Reactor began powering itself in 1951. The first nuclear power plant designed to provide energy to a community was established in Obninsk, Russia, in 1954. Building nuclear reactors requires a high level of technology , and only the countries that have signed the Nuclear Non-Proliferation Treaty can get the uranium or plutonium that is required. For these reasons, most nuclear power plants are located in the developed world. Nuclear power plants produce renewable, clean energy . They do not pollute the air or release  greenhouse gases . They can be built in urban or rural areas , and do not radically alter the environment around them. The steam powering the turbines and generators is ultimately recycled . It is cooled down in a separate structure called a cooling tower . The steam turns back into water and can be used again to produce more electricity . Excess steam is simply recycled into the atmosphere , where it does little harm as clean water vapor . However, the byproduct of nuclear energy is radioactive material. Radioactive material is a collection of unstable atomic nuclei . These nuclei lose their energy and can affect many materials around them, including organisms and the environment. Radioactive material can be extremely toxic , causing burns and increasing the risk for cancers , blood diseases, and bone decay .

Radioactive waste is what is left over from the operation of a nuclear reactor . Radioactive waste is mostly protective clothing worn by workers, tools, and any other material that have been in contact with radioactive dust. Radioactive waste is long-lasting. Materials like clothes and tools can stay radioactive for thousands of years. The government regulates how these materials are disposed of so they don't contaminate anything else. Used fuel and rods of nuclear poison are extremely radioactive . The used uranium pellets must be stored in special containers that look like large swimming pools. Water cools the fuel and insulates the outside from contact with the radioactivity. Some nuclear plants store their used fuel in dry storage tanks above ground. The storage sites for radioactive waste have become very controversial in the United States. For years, the government planned to construct an enormous nuclear waste facility near Yucca Mountain, Nevada, for instance. Environmental groups and local citizens protested the plan. They worried about radioactive waste leaking into the water supply and the Yucca Mountain environment, about 130 kilometers (80 miles) from the large urban area of Las Vegas, Nevada. Although the government began investigating the site in 1978, it stopped planning for a nuclear waste facility in Yucca Mountain in 2009. Chernobyl Critics of nuclear energy worry that the storage facilities for radioactive waste will leak, crack, or erode . Radioactive material could then contaminate the soil and groundwater near the facility . This could lead to serious health problems for the people and organisms in the area. All communities would have to be evacuated . This is what happened in Chernobyl, Ukraine, in 1986. A steam explosion at one of the power plants four nuclear reactors caused a fire, called a plume . This plume was highly radioactive , creating a cloud of radioactive particles that fell to the ground, called fallout . The fallout spread over the Chernobyl facility , as well as the surrounding area. The fallout drifted with the wind, and the particles entered the water cycle as rain. Radioactivity traced to Chernobyl fell as rain over Scotland and Ireland. Most of the radioactive fallout fell in Belarus.

The environmental impact of the Chernobyl disaster was immediate . For kilometers around the facility , the pine forest dried up and died. The red color of the dead pines earned this area the nickname the Red Forest . Fish from the nearby Pripyat River had so much radioactivity that people could no longer eat them. Cattle and horses in the area died. More than 100,000 people were relocated after the disaster , but the number of human victims of Chernobyl is difficult to determine . The effects of radiation poisoning only appear after many years. Cancers and other diseases can be very difficult to trace to a single source. Future of Nuclear Energy Nuclear reactors use fission, or the splitting of atoms , to produce energy. Nuclear energy can also be produced through fusion, or joining (fusing) atoms together. The sun, for instance, is constantly undergoing nuclear fusion as hydrogen atoms fuse to form helium . Because all life on our planet depends on the sun, you could say that nuclear fusion makes life on Earth possible. Nuclear power plants do not have the capability to safely and reliably produce energy from nuclear fusion . It's not clear whether the process will ever be an option for producing electricity . Nuclear engineers are researching nuclear fusion , however, because the process will likely be safe and cost-effective.

Nuclear Tectonics The decay of uranium deep inside the Earth is responsible for most of the planet's geothermal energy, causing plate tectonics and continental drift.

Three Mile Island The worst nuclear accident in the United States happened at the Three Mile Island facility near Harrisburg, Pennsylvania, in 1979. The cooling system in one of the two reactors malfunctioned, leading to an emission of radioactive fallout. No deaths or injuries were directly linked to the accident.

Articles & Profiles

Media credits.

The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit. The Rights Holder for media is the person or group credited.

Illustrators

Educator reviewer, last updated.

October 19, 2023

User Permissions

For information on user permissions, please read our Terms of Service. If you have questions about how to cite anything on our website in your project or classroom presentation, please contact your teacher. They will best know the preferred format. When you reach out to them, you will need the page title, URL, and the date you accessed the resource.

If a media asset is downloadable, a download button appears in the corner of the media viewer. If no button appears, you cannot download or save the media.

Text on this page is printable and can be used according to our Terms of Service .

Interactives

Any interactives on this page can only be played while you are visiting our website. You cannot download interactives.

Related Resources

• Future Energy Systems Center
• Studies and reports
• Funding opportunities
• Carbon Management
• Electric Power
• Energy storage
• Low-carbon Fuels
• Transportation
• Undergraduate education
• Graduate & postdoctoral
• Online education
• Education research
• Current members
• Energy Futures
• In the media
• Affiliations

Nuclear energy

The Future of Nuclear Energy in a Carbon-Constrained World

A new look for nuclear power

The future of the nuclear fuel cycle, nano-structured alloys against corrosion in advanced nuclear plants.

Understanding corrosion in power plants & other systems

The Future of Nuclear Power

Publications.

September 2018

The benefits of nuclear flexibility in power system operations with renewable energy

Center for Advanced Nuclear Energy Systems Reports

January 2018

Related news

Selecting the right metal can alleviate the corrosion problem.

FUSars program offers undergraduates in-depth research opportunities in fusion science and energy.

DOE awards research funds for offshore nuclear generation

The U.S. Department of Energy has granted funding to the MIT Energy Initiative, Core Power, and the Idaho National Laboratory for a three-year study. The study will look into the development of offshore floating nuclear power generation in the United States.

Department of Nuclear Science and Engineering

Plasma Science and Fusion Center

Nuclear Reactor Laboratory

Office of the Provost

MIT Energy Initiative

Sloan School of Management

Office of the Vice President for Research

Help | Advanced Search

Nuclear Experiment

Title: experimental study on deuterium-deuterium thermonuclear fusion with interface confinement.

Abstract: Nuclear fusion is recognized as the energy of the future, and huge efforts and capitals have been put into the research of controlled nuclear fusion in the past decades. The most challenging thing for controlled nuclear fusion is to generate and keep a super high temperature. Here, a sonication system, combining with micro-scale fluid control techniques, was built to generate cavitation within a limited region. As bubbles being rapidly compressed, high temperature plasma generated interior leads to particle emissions, where a Cs2LiYCl6: Ce3+ (CLYC) scintillator was used to collect the emission events. The pulse shape discrimination methods applied on captured signals revealed that only gamma ray events were observed in sonication with normal water as excepted, while obvious separation of neutron and gamma ray events was surprisingly identified in sonication with deuterated water. This result suggested that neutrons were emitted from the sonicated deuterated water, i.e. deuterium-deuterium thermonuclear fusion was initiated. This study provides an alternative and feasible approach to achieve controllable nuclear fusion and makes great sense for future researches on the application of fusion energy.

Submission history

Access paper:.

• Other Formats

References & Citations

• INSPIRE HEP
• Google Scholar
• Semantic Scholar

BibTeX formatted citation

Bibliographic and Citation Tools

Code, data and media associated with this article, recommenders and search tools.

• Institution

arXivLabs: experimental projects with community collaborators

arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website.

Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them.

Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs .

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

• View all journals
• My Account Login
• Explore content
• About the journal
• Publish with us
• Sign up for alerts
• Open access
• Published: 22 May 2024

Observation of a promethium complex in solution

• Darren M. Driscoll   ORCID: orcid.org/0000-0001-8859-8016 1 ,
• Frankie D. White 2 ,
• Subhamay Pramanik 1 ,
• Jeffrey D. Einkauf 1 ,
• Bruce Ravel   ORCID: orcid.org/0000-0002-4126-872X 3 ,
• Dmytro Bykov 4 ,
• Santanu Roy   ORCID: orcid.org/0000-0001-6991-8205 1 ,
• Richard T. Mayes 2 ,
• Lætitia H. Delmau 2 ,
• Samantha K. Cary 2 ,
• Thomas Dyke 1 ,
• April Miller 2 ,
• Matt Silveira 2 ,
• Shelley M. VanCleve 2 ,
• Sandra M. Davern 2 ,
• Santa Jansone-Popova   ORCID: orcid.org/0000-0002-0690-5957 1 ,
• Ilja Popovs   ORCID: orcid.org/0000-0002-9767-3353 1 &
• Alexander S. Ivanov   ORCID: orcid.org/0000-0002-8193-6673 1  

Nature volume  629 ,  pages 819–823 ( 2024 ) Cite this article

1 Citations

218 Altmetric

Metrics details

• Chemical bonding
• Chemical physics
• Nuclear chemistry

Lanthanide rare-earth metals are ubiquitous in modern technologies 1 , 2 , 3 , 4 , 5 , but we know little about chemistry of the 61st element, promethium (Pm) 6 , a lanthanide that is highly radioactive and inaccessible. Despite its importance 7 , 8 , Pm has been conspicuously absent from the experimental studies of lanthanides, impeding our full comprehension of the so-called lanthanide contraction phenomenon: a fundamental aspect of the periodic table that is quoted in general chemistry textbooks. Here we demonstrate a stable chelation of the 147 Pm radionuclide (half-life of 2.62 years) in aqueous solution by the newly synthesized organic diglycolamide ligand. The resulting homoleptic Pm III complex is studied using synchrotron X-ray absorption spectroscopy and quantum chemical calculations to establish the coordination structure and a bond distance of promethium. These fundamental insights allow a complete structural investigation of a full set of isostructural lanthanide complexes, ultimately capturing the lanthanide contraction in solution solely on the basis of experimental observations. Our results show accelerated shortening of bonds at the beginning of the lanthanide series, which can be correlated to the separation trends shown by diglycolamides 9 , 10 , 11 . The characterization of the radioactive Pm III complex in an aqueous environment deepens our understanding of intra-lanthanide behaviour 12 , 13 , 14 , 15 and the chemistry and separation of the f -block elements 16 .

Similar content being viewed by others

Polyoxometalates as ligands to synthesize, isolate and characterize compounds of rare isotopes on the microgram scale

Structural and spectroscopic characterization of an einsteinium complex

Structure and bonding of a radium coordination compound in the solid state

One reason promethium (Pm) was so elusive for many years, despite a relatively low atomic number, is that it is the only element in the lanthanide (Ln) series (elements with atomic numbers 57–71) with no stable isotopes. Nowadays, mostly synthetic radioisotope 147 Pm (with half-life τ 1/2  = 2.62 years) is produced and isolated in small quantities through nuclear fission in reactors and subsequent tedious purification steps for many applications. Promethium uses range from long-life nuclear batteries used in space craft to radiation therapy 7 , 8 . A key obstacle impeding the efficient recovery of this critical element resides in our limited comprehension of the Pm coordination chemistry. In contrast to other lanthanides that favour the +3 oxidation state under ambient conditions, even the most fundamental characteristics of Pm in aqueous solution, including the bond distances and coordination number, remain unexplored. This valuable information is exceptionally challenging to obtain due to its radioactivity, synthetic nature and lack of availability. Only a few simple inorganic Pm III solids, such as halides 17 , oxide 18 , oxalate 19 , molybdate and tungstate 20 have been prepared and characterized by X-ray powder diffraction to determine the lattice parameters. Furthermore, the absorption bands in the visible spectrum 17 , 21 , 22 , Raman spectra 23 and magnetic susceptibility 24 of the Pm III oxide and halides were reported. Beyond these examples, the fundamental chemistry of Pm is virtually unknown, and there are no experimental data to benchmark theoretical models for predicting Pm chemical bonding, structure and reactivity in solution. In addition, it is well known that the gradual population of the 4 f electron shell in conjunction with relativistic effects cause a continuous decrease in the size of the ionic radii along the lanthanide series, leading to structural changes in Ln complexes. Whereas this lanthanide contraction phenomenon taught in general chemistry textbooks has been inferred mostly from theory 25 , 26 , 27 , 28 , 29 and Shannon’s effective ionic radii database 30 , it still lacks experimental structural evidence for a complete set of lanthanides in solution that includes radioactive Pm 31 , 32 , 33 , 34 , 35 , 36 . Advancing our fundamental knowledge in this field is critical for rationalizing and predicting the structurally diverse coordination chemistry shown by lanthanides 1 , 3 , 12 .

Towards this goal, we report our experimental and computational efforts to investigate the Pm ion binding by a multidentate ligand in an aqueous solution, taking advantage of the recently enhanced isotope separation techniques ( Methods ), which have enabled the production of 147 Pm in sufficient quantities and purity levels necessary for fundamental studies (Fig. 1a ). A new, water-soluble complexing agent, bispyrrolidine diglycolamide (PyDGA) (Fig. 1b ) was synthesized and used for Pm complexation. The DGA family of neutral ligands is well established for efficient lanthanide and actinide chelation and separation 9 , 10 , showing stable binding mode for Ln III ions 37 , 38 . These characteristics enabled the detection and characterization of the homoleptic [Pm(PyDGA) 3 ] 3+ complex by X-ray absorption spectroscopy (XAS) measurements at the National Synchrotron Light Source II (NSLS-II). The experimental results corroborated by the quantum chemical calculations provide the missing piece necessary for a comprehensive study of the impact of f -electron count on Ln contraction in the entire isostructural series of Ln complexes. This discovery reveals distinctive structural and electronic characteristics extending beyond the gradual ionic radii changes.

a , Photograph of purified Pm III compound prepared in this study. The depicted pink-coloured 147 Pm(NO 3 ) 3 · n H 2 O ( n  < 9) solid residue was obtained after several purification steps and used in a Pm III complexation. b , Each PyDGA ligand molecule consists of two amide carbonyl oxygen groups and one ether oxygen atom, enabling high aqueous solubility. This chelator coordinates with the promethium cation in a tridentate fashion to form the 1:3 complex by providing nine metal-binding O donor atoms in the first coordination sphere of Pm III .

Our motivation for probing the Pm complexation in the solution phase arises from the absence of crystal lattice effects that could affect the measured bond distances. Also, a dilute aqueous environment is generally free from the heat and damage inherent to radioactive materials, which are more pronounced in the solid state. Thus, for XAS investigations, the sample was prepared in 0.01 M HNO 3 solution containing 147 Pm (90 µl, 8.5 mM) complexed with PyDGA at a roughly 1 to 20 metal ion-to-ligand ratio to ensure the full ion chelation and formation of the [Pm(PyDGA) 3 ] 3+ complex (Fig. 1b ). The solution was then triply contained and secured in a rigid aluminium sample holder (Extended Data Fig. 1 ). The L 3 - and L 1 -edge XAS spectra were acquired at room temperature in fluorescence mode using a Vortex four-element silicon-drift detector at beamline 6-BM of NSLS-II (Fig. 2 ; L 1 -edge XAS results are shown in Extended Data Fig. 2 ). The X-ray absorption near-edge structure (XANES) indicates that the Pm spectral features are consistent with the XANES data measured for other adjacent lanthanides having +3 oxidation state (Extended Data Fig. 3a ). The position of the L 3 -absorption edge (the inflection point) was determined to be at 6,464.4 eV (calibrated to the K-edge of an Fe foil, 7,112.0 eV, and measured with an instrumental uncertainty below 0.1 eV). The XANES spectrum can be separated into four distinct regions (Fig. 2a ). On the basis of our density functional theory (DFT) restricted open shell configuration interaction singles (DFT–ROCIS) and multiple scattering theory calculations (Extended Data Fig. 3b,c ), region I corresponds to transitions from Pm 2 p to 4 f /5 d orbitals, and the most intense peak II is dominated by 2 p core electron excitations to 5 d but with some PyDGA orbital contributions. Less visible peak III can be attributed to transitions involving Pm 4 f /5 d /ligand orbitals, whereas the origin of broad feature IV is complex with leading components from 2 p to 5 d /ligand and Pm 4 f dz 3 orbitals.

a , Pm L 3 -edge XANES spectrum (black line) and its interpretation using DFT–ROCIS calculations (circles). E is the incident photon energy and the corresponding orbitals participating in the core electron excitations are shown in Extended Data Fig. 3b . b , c , Pm EXAFS data (squares), the fit (pink line) representing model scattering paths associated with the Pm complex and the AIMD simulated EXAFS (turquoise dashed line). b , L 3 -edge EXAFS spectrum of the Pm complex in solution where k is the energy of the photoelectron in wavenumbers and k 3 χ ( k ) is the k 3 -weighted EXAFS function. Data between 2.3 and 7.8 Å −1 were Fourier transformed using a Hanning window to obtain real-space information. c , Magnitude of the Fourier transform (FT) (black squares) and the real component of the Fourier transform (empty squares). The data were fit over the range from 1.4 to 3.2 Å. Spectra are not phase adjusted. d , Snapshot of the Pm complex surrounded by water molecules from the AIMD simulations. e , Formation of the dative Pm–O bond in the Pm complex in terms of overlapping amide carbonyl oxygen lone pair, on the right, with the Pm 5 d acceptor orbital, on the left. Only the local Pm–ligand environment is visualized for clarity. f , The resulting Pm–O bonding NBO that includes roughly 4% Pm character. The Pm hybrid’s nodal character in the bond is not visible because its amplitude is below the 0.035 amplitude cut-off for the orbital visualization.

To investigate the local coordination structure around the Pm III ion, we analysed the extended X-ray absorption fine structure (EXAFS) of the [Pm(PyDGA) 3 ] 3+ complex. The Pm EXAFS data in Fig. 2b show the expected sinusoidal-like behaviour; however, a sharp feature can be seen at 8.2 Å −1 , which is attributed to the presence of a small amount of Nd III (L 2 -edge) and 147 Sm III (L 3 -edge), a decay product of 147 Pm. Hence real-space functions (Fig. 2c ) were produced using a Fourier transform of the EXAFS data that contain only Pm information (2.3 ≤  k  ≤ 7.8 Å −1 ), giving a physical description of the atomic arrangement around the Pm ion. The Fourier transform of the EXAFS reveals two intense features at 1.9 and 2.8 Å (non-phase corrected), presumably corresponding to the inner-sphere Pm–O and more distant Pm–C scattering correlations originating from Pm III complexation by PyDGA. A two-shell oxygen-carbon model based on the Pm surrogate crystal structure (Extended Data Fig. 4 ) was developed to fit the EXAFS data. According to this representation, the first shell comprised six amide carbonyl and three ether O donors, and the second shell at longer distances accounted for the six sp 3 -hybridized (ether moiety) and six sp 2 -hybridized (carbonyl moiety) C atoms from the PyDGA scaffold. However, given the limited k- space data, affecting the interatomic resolution, and the dynamic nature of the solution phase at room temperature, amido and ether O, as well as sp 3 - and sp 2 -C distances, could not be resolved and were each fitted in a conservative manner with the Ln–O and Ln–C single scattering paths. This resulted in an average Pm–O bond distance of 2.476(16) Å (Debye–Waller factor σ 2  = 0.006(1) Å 2 ) and an average Pm–C distance of 3.38(7) Å ( σ 2  = 0.02(1) Å 2 ), consistent with Pm III chelation by three PyDGA ligands (Extended Data Table 1 ).

To further gain insights into the dynamic structural behaviour of Pm III complexation in an aqueous environment, we performed ab initio molecular dynamics (AIMD) simulations. The theoretical EXAFS spectrum and its Fourier transform (Fig. 2b,c ) were simulated directly from the AIMD trajectory and show very good agreement with the experimental data, validating the formation of a homoleptic [Pm(PyDGA) 3 ] 3+ complex (Fig. 2d ). Key structural parameters align well with those determined by the EXAFS experiments, as can be judged from the analyses of radial distribution functions (RDFs), with the AIMD predicted Pm–O bond length of 2.48 Å (Extended Data Fig. 5 ). Beyond the inner-sphere Pm–O correlations, the AIMD results also indicated some water structuring around the complex at 4.43 Å through transient hydrogen bond interactions with the O donor groups of the PyDGA ligands. It is also worth noting that, like in the experimental EXAFS data, the amide carbonyl and etheric Pm–O bonds could not be resolved in the AIMD and thus appeared as a single peak in the corresponding RDF, pointing to the dynamic nature of the first-sphere ligand-metal interactions in aqueous solution (Supplementary Video  1 ).

Next, we performed natural bond orbital (NBO) calculations to examine the nature of Pm–O bonding. Natural population analysis indicates that the promethium 5 d and 6 s orbitals are substantially populated (0.82 electrons |e| and 0.17 |e|, respectively), with a non-negligible population of the vacant 4 f orbitals (0.07 |e|). The dative Pm–O bonds originate from a characteristic σ-type donation of electron density from O lone pairs to the Pm centre. Figure 2e shows the representative leading orbital interaction that stems from an overlap of the O lone pair with an acceptor orbital of primarily 5 d character on Pm, resulting in the Pm–O NBO, which is predominantly localized on the oxygen atom (Fig. 2f ). The strength of interactions involving amide carbonyl O groups was found to be only slightly higher than that involving ether oxygens. This was confirmed by the comparable calculated values of Wiberg bond indices for the amidic (0.12) and etheric (0.08) Pm–O bonds, pointing to their prevalent ionic nature and explaining their dynamic behaviour in aqueous solution. As a result, these bonding characteristics do not exert substantial ligand field effects, leading to the challenges that are frequently encountered in the selective recovery of Pm and other rare-earth elements 1 .

Having established promethium coordination and bond lengths, we studied the remaining lanthanide (La III , Ce III , Pr III , Nd III , Sm III , Eu III , Gd III , Tb III , Dy III , Ho III , Er III , Tm III , Yb III , Lu III ) complexes with PyDGA using XAS (Fig. 3 and Extended Data Fig. 6 ) to understand how the solution structure of the coordination complex transforms across the lanthanide series. The Fourier transform-EXAFS results in Fig. 3a,b show that the positions and intensities of the main features corresponding to the Ln–O distances vary slightly between the lanthanides. This is expected on the basis of the different harmonics generated from the shortening of the inner-sphere bonds caused by the Ln contraction. Furthermore, the shrinkage of the Ln–O bonds is corroborated by the trend in the relative energy positions of the Ln L 3 -edge XANES spectral features (Extended Data Fig. 3a ), consistent with the results of a recent study 39 on some isostructural Ln compounds using high-energy-resolution fluorescence-detected XANES 40 , 41 measurements.

a , b , One-dimensional profiles ( a ) and 2D intensity map ( b ) of the real component of the Fourier transformed EXAFS data for the lanthanide complexes, visualizing the contraction of the first shell across the lanthanide series. Spectra are not phase adjusted. c , The dependence of the Ln–O bond distances on the number of 4 f electrons, revealing accelerated contraction from La III to Pm III followed by a steadier Ln–O bond shortening for the heavier lanthanides (1 σ error bars associated with each data point are based on EXAFS fitting uncertainty).

Good fits to the Ln-PyDGA EXAFS data were obtained with the model used for promethium, giving physically sound parameters (Extended Data Table 2 ) and suggesting that the [Ln(PyDGA) 3 ] 3+ species prevail in the aqueous solution across the series. Figure 3c represents the most comprehensive view of the Ln contraction phenomenon obtained from experiments and shows how the inner-sphere Ln–O bond distances change depending on the number of 4 f electrons in the electronic structure of Ln III . By monitoring the decrease of Ln–O bonds from La (2.560(21) Å) to Lu (2.329(12) Å), a quadratic dependence across the series was observed and fitted by a polynomial regression (Extended Data Fig. 7 ). Filling the 4 f orbitals apparently influences shielding of the nuclear charge and according to our data this effect was most pronounced early in the series from La to Pm, accounting for as much as roughly 36% of the overall Ln contraction. After Pm, there was a steadier shortening of the Ln–O bonds. This behaviour is in line with Shannon’s effective ionic radii decrease (at coordination number of nine) 30 , which is larger at the beginning of the series than at the end. It is also worth mentioning that the observed accelerated contraction parallels well with the Ln extraction performance of lipophilic diglycolamides in a liquid–liquid extraction process, where better separation between adjacent lanthanides was achieved for the light (La–Nd) than for the heavy (Er–Lu) members of the series 9 , 10 . Moreover, by adapting the modified Slater theoretical model 36 to our experimental dataset, we derived a value of the shielding constant for f electrons ( s  = 0.74), which is in good agreement with the previously reported and generally accepted value of 0.69 obtained from the Ln ionization energies 42 . We note, however, that accurate fully relativistic quantum mechanical calculations using a new generation of supercomputers will be important to further investigate the observed Ln contraction behaviour in future studies.

After almost eight decades since the discovery of the element Pm, its coordination complex has been synthesized and characterized in solution using modern synchrotron spectroscopy tools. The determined Pm–O bond distance of 2.476(16) Å is in line with quantum chemical investigations and originates from a σ-type donation of electron density from the ligands to the primarily 5 d vacant orbitals of Pm. Finally, this previously inaccessible piece of information allowed us to complete structural studies of a full lanthanide set of isostructural complexes in solution, ultimately establishing and confirming the Ln contraction phenomenon solely based on the experimental structural data. These results are expected to contribute to our fundamental understanding and prediction of the coordination chemistry of lanthanides and scarce f -block elements 43 , 44 , 45 , 46 , 47 , 48 , with pertinence to emergent rare-earth separation and radiopharmaceutical technologies.

Materials synthesis

The PyDGA ligand was synthesized according to the following procedure. In a round-bottom flask equipped with a stir bar, pyrrolidine (11.68 ml, 2.5 equiv.) was combined with anhydrous CH 2 Cl 2 (120 ml) and Et 3 N (19.58 ml, 2.5 equiv.). The reaction mixture was stirred for 15 min in an ice-water bath. Diglycolyl chloride (6.67 ml, 1.0 equiv.) was added dropwise under an inert atmosphere (Argon), and the reaction mixture was allowed to warm up to room temperature, followed by stirring for the next 12 h. Afterwards, CH 2 Cl 2 was evaporated to dryness under reduced pressure, and the residue was dissolved in 100 ml of methanol and treated with K 2 CO 3 (23.32 g, 3.0 equiv.) to convert Et 3 N·HCl to KCl and free triethylamine. The reaction mixture was filtrated through a short Celite plug and rinsed with excess methanol to separate the solid salt, and the filtrate was concentrated to yield a crude product. The crude product was purified on CombiFlash R f automated flash chromatography system using normal phase silica gel as a stationary phase and gradient 0–20% MeOH in CH 2 Cl 2 as an eluent to yield a white crystalline solid (12.00 g, 89%) (see Extended Data Fig. 8 for spectra from 1 H nuclear magenetic resonance, 13 C nuclear magenetic resonance, Fourier transform-infrared spectroscopy and electrospray ionization with mass spectrometry).

147 Pm experimental preparation

Caution! 147 Pm ( τ 1/2  = 2.62 years) has potential health risks due to its β emission. Processing, preparation and handling were carefully performed in a radiological facility with gloveboxes and fume hoods equipped with HEPA (high-efficiency particulate absorbing) filters. The preparation of samples was carefully surveyed and monitored for contamination by trained radiological control technicians.

The promethium was harvested from the waste solutions generated by the production of 238 Pu from irradiated 237 Np targets. The concentration and initial crude separation of promethium was done using a separation column 49 in the hot cell. This had the advantage of obtaining the Pm in a manageable volume and rejecting most other fission products. A careful gradient separation substantially decreased the amount of the high gamma-emitting lanthanide fission products, specifically 141,144 Ce and 154,155,156 Eu. The solution was further purified by repeating separation cycles in smaller columns within shielded caves or gloveboxes, leaving essentially a Pm solution still containing traces of curium as these two elements typically co-extract and costrip during this process. The separation between promethium and curium was accomplished using a TALSPEAK-based solvent extraction system 50 with several scrubs to reach the desired purity.

A 70 mM 147 Pm III stock solution in 0.01 M HNO 3 was prepared for distribution into the XAS sample after the dilution. To ensure the complete complexation of promethium, a solution (roughly 90 µl) of 8.5 mM 147 Pm(NO 3 ) 3 containing 180 mM PyDGA was prepared. The obtained solution was then loaded into a polyimide capillary (1.8 mm inner diameter by 5 cm long, 0.05 mm thickness, Cole-Parmer) using a Hamilton syringe and then sealed twice with Devcon 2 Ton epoxy (Extended Data Fig. 1 ). Once the epoxy had dried completely, the sample was transferred from a glovebox to a radiological fume hood for further decontamination. The sample was then surveyed and doubly contained for shipment to the XAS beamline.

The radiochemical purity of the recovered 147 Pm(NO 3 ) 3 used for the [Pm(PyDGA) 3 ] 3+ sample preparation was more than 99.9%. The residual concentration of 151 Sm was assessed at below the detection level. A small quantity of 146 Nd was present in the sample due to challenging separations of the adjacent lanthanides using the aforementioned techniques. Traces of Sm present in the sample on the moment of XAS measurements originated from the radioactive decay of promethium to the daughter samarium according to the following process: 147 Pm (β − →) 147 Sm. Roughly 77 days had passed between the Pm purification and XAS data collection. On the basis of the τ 1/2  = 2.62 years of the radioactive decay, up to 5.632% of the starting 147 Pm had decayed into 147 Sm at the time of the sample measurements at NSLS-II.

XAS data collection and analysis

XAS measurements were acquired at the Ln L 3 - and L 1 -edges at beamline 6-BM of the NSLS-II. For the dilute solution of Pm, measurements were performed in fluorescence mode using a four-element silicon-drift detector with no beam-induced changes to the sample being detected. This was checked by comparing individual XAS scans, which did not show any abnormal changes. For all other Ln (La–Nd, Sm–Lu), aqueous solutions of 0.1 M Ln(NO 3 ) 3 (prepared from commercial solid Ln III nitrate salts with 99.9% metal purity) and 0.4 M PyDGA were combined in 0.01 M HNO 3 , and then placed into polyether ether ketone (PEEK) liquid holders of varying thickness with polyimide windows and sealed with epoxy, affording XAS data collection in transmission mode. The data for Ln, except Pm, were energy-calibrated to the main edge from the spectra of Ln oxide standards. The Ln dataset consisted of three scans, which were averaged and background subtracted. For the Pm, 20 (L 3 -edge) and 30 (L 1 -edge) individual scans were merged with first derivative maxima at 6,464.4 and 7,441.4 eV, respectively (calibrated to the K-edge of an Fe foil, 7,112.0 eV). Data normalization was performed using the Athena software package 51 .

Ejected photoelectrons are defined by their wavenumber ( k ) in relation to the absorption edge energy ( E 0 ) through the equation

where m e is the electron mass and ħ is the reduced Planck’s constant. The experimental EXAFS oscillations of each sample, χ ( k ), were extracted from the normalized XAS data using subtraction of a spline and a cut-off distance ( R BKG ) that varied between 1.2 and 1.0 Å. For analysis of the EXAFS region, we used the EXAFS relationship given by

where the index i is considered the path index and the χ ( k ) is calculated as the summation over all paths. For fitting of the EXAFS, FEFF6 within the Artemis software package 51 was used considering the experimental χ ( k ) data weighted by k 3 . In equation ( 2 ), F i ( k ), δ i ( k ) and λ ( k ) represent the effective scattering amplitude, total phase shift and mean-free-path of the photoelectron and each are derived from the FEFF6 code. The many-body amplitude-reduction factor, S 0 2 , was fixed to 1. Furthermore, N i values, the degeneracy of the path and therefore the coordination numbers for single scattering paths, were held constant (9 and 12 for the first and second coordination shells, respectively), as inferred from the stable 1:3 complexation and the respective Ln-DGA crystal structures 37 . Therefore, the parameters still to be fit included R i , the half-path length; σ 2 i , the Debye–Waller factor; and C 3, i , the asymmetry of the distribution. Variation of C 3, i was found to provide negligible improvements on the single scattering paths and thus was not included in the fitting process. Furthermore, a single non-structural parameter for all paths, Δ E 0 , was varied to align the k  = 0 point of the experimental data and theory. Fits were performed in R space using a Hanning window for k -space data. For the EXAFS fits, we focused on the Ln–O and Ln–C single scattering paths originating from the binding of three PyDGA ligands. For all lanthanides, both the L 3 - and L 1 -edge spectra were simultaneously fit with only the addition of a second Δ E 0 variable for the L 1 -edge data. The L 3 -edge dataset included both the single scattering paths for Ln–O and Ln–C, whereas the L 1 -edge used a restricted R -window and only the Ln–O scattering path was fitted. This approach allowed the number of variables (six) per fit to stay below the number of independent data points (ten) available in the primary Pm data with k max  = 7.8 Å −1 .

X-ray diffraction studies

Crystallization of [Sm(PyDGA) 3 ][Sm(NO 3 ) 6 ]·3C 2 H 5 OH: a solution (1.0 ml) of Sm(NO 3 ) 3 (56 mg, 125 mM) was added to 1 ml of CH 3 OH:C 2 H 5 OH (1:1) solution of PyDGA (60 mg, 250 mM), followed by vapour diffusion under isopropyl ether inside a refrigerator at 5 °C. After 7 days, plate shape (monoclinic, P 2 1 /c) crystals were obtained. Crystallization of [Er(PyDGA) 3 ] 2 [Er(NO 3 ) 5 ] 3 ·2H 2 O: a solution (1.0 ml) of Er(NO 3 ) 3 (110 mg, 250 mM) was added to a 1 ml of CH 3 OH:H 2 O (9:1) solution of PyDGA (120 mg, 500 mM), followed by vapour diffusion under diethyl ether at room temperature. After 3 days, triclinic ( P –1) crystals were obtained. X-ray diffraction data were collected at 100 K on a Bruker D8 Advance Quest diffractometer equipped with a graphite monochromator using Mo K α radiation ( λ  = 0.71073 Å). The frames were integrated with the Bruker SAINT software package using a narrow-frame algorithm. An empirical absorption correction using the multi-Scan method SADABS was applied to the data. The structure was solved by direct methods using the Bruker SHELXTL Software Package, v.2018/3. Non-hydrogen atoms were refined anisotropically. Hydrogen atoms were calculated and placed in idealized positions. The CIF files within this report were archived in the Cambridge Crystallographic Data Centre (CCDC) under CCDC depositions 2279633 and 2279634.

Computational details

The Vienna ab initio simulation package (VASP) 52 , 53 was used to conduct AIMD simulations using spin-polarized DFT. The valence electronic states were expanded on a basis of plane waves, whereas the core valence interactions were described using the projector augmented wave approach and standard f -in-valence projector augmented wave potential was used for Pm 54 , 55 . The plane-wave kinetic energy cut-off was set to 650 eV and the Perdew–Burke–Ernzerhof (PBE) GGA functional 56 was used to describe the exchange-correlation interactions. The Brillouin zone was sampled using the gamma point approximation. The DFT-D3 approach of Grimme 57 was used to account for the van der Waals interactions. The initial structure of the Pm complex–water system (a periodic cubic box of 18 Å length containing one complex and 144 water molecules) was pre-equilibrated for 5 ns in a canonical ensemble at a temperature of 300 K using the extended polymer consistent force field (PCFF+) 58 supported in MedeA-LAMMPS 59 , 60 . As the nitrate counterions are expected to be completely dissociated and/or screened from [Pm(PyDGA) 3 ] 3+ in a dilute aqueous environment 38 , they were not explicitly introduced in the molecular dynamics simulations and the +3 charge on the Pm complex was instead compensated by a uniform background charge. AIMD simulations at 300 K were performed using the Nosé–Hoover thermostat 61 , 62 with a time step of 1 femtosecond (fs). After equilibrating for 10 picoseconds (ps), the AIMD trajectory was collected for 50 ps and used for the RDF analysis. Furthermore, the evenly spaced 1,000 configurations from the last 10 ps of the AIMD trajectory were used to compute and simulate AIMD-EXAFS spectra using the Green’s function-based approach implemented in the FEFF9 package 63 . Before running the FEFF9 code, a coordinate transformation procedure was performed to ensure that the absorbing ion, Pm, was at the centre of the simulation box and the other atoms were arranged according to their distances from Pm in the ascending order. The multiple scattering path expansion within 8.5 Å of Pm was used during the self-consistent cycle. All multiple scattering paths were included within the plane-wave approximation except the ones with the mean amplitude below 0.01%. XANES and projected density of states calculations of the Pm complex were also performed using FEFF9 (ref. 63 ). The XANES spectrum was computed using the full multiple scattering, self-consistent field and Hedin–Lundqvist energy-dependent exchange-correlation potential, considering both dipolar and quadrupolar transitions. The ground state potential was used for the background function. For the projected density of states calculations, a Lorentzian broadening parameter of 0.05 eV was applied.

Cluster model calculations in the gas phase were performed with the Gaussian v.16, Revision A.03 program package 64 . Geometry optimizations enlisted unrestricted Kohn–Sham methods, with the aug-cc-pVTZ basis set for the light atoms 65 . The small-core f -in-valence quasi-relativistic ECP28MWB/ECP28MWB_ANO effective-core-potential/basis-set 66 was used for Pm and the complex was treated as a triply charged quintet with four unpaired f electrons. The optimized structure at the PBE0-D3 level of theory 67 was confirmed as a true minimum by analytical frequency calculations. The Pm first- and second-sphere bond distances agreed well with the EXAFS (Extended Data Table 1 ) and AIMD data (Extended Data Fig. 5 ), and this structure was used for our subsequent analysis. The Pm L 3 -edge XANES calculations were performed with the ORCA v.5.0 program 68 . The ROCIS method was used on top of the DFT wave function (DFT–ROCIS) 69 , 70 . The B3LYP functional 71 was deployed together with Douglas–Kroll–Hess (DKH) Hamiltonian to account for relativistic effects. The DKH-optimized all-electron TZ-quality basis set was applied to all elements except for Pm, in which segmented all-electron relativistically contracted basis was used (the dkh-def2-tzvp and sarc-dkh-tzvp in ORCA notation, correspondently). Spin–orbit coupling as well as lower and higher multiplets were accounted for. The analysis was done using the natural difference orbitals 72 . To account for systematic errors in the calculation of transition energies, the simulated spectrum was uniformly shifted by 175 eV to match the experimental absorption edge energy. The bonding in the Pm complex was examined by using the NBO methodology 73 , as implemented in the NBO7 program 74 , 75 . Molecular orbital diagrams were drawn with an isovalue of 0.035 a.u. Model representations in the figures were prepared using the UCSF Chimera software 76 . The Slater shielding constant for 4 f electrons was derived based on the methodology described by Seitz et al. 36 .

Data availability

All data supporting the findings are available within the paper. Additional details are available on request to the corresponding authors. The X-ray crystallographic data for the Sm and Er-PyDGA structures reported in this study have been deposited at the CCDC, under deposition numbers 2279633 and 2279634 , respectively. These data can be obtained free of charge from the CCDC via www.ccdc.cam.ac.uk/data_request/cif .

Code availability

All in-house code used in this study is available via Zenodo at https://doi.org/10.5281/zenodo.10045182 (ref. 77 ).

Cheisson, T. & Schelter, E. J. Rare earth elements: Mendeleev’s bane, modern marvels. Science 363 , 489–493 (2019).

Article   ADS   CAS   PubMed   Google Scholar  

Cockell, C. S. et al. Space station biomining experiment demonstrates rare earth element extraction in microgravity and Mars gravity. Nat. Commun. 11 , 5523 (2020).

Article   ADS   CAS   PubMed   PubMed Central   Google Scholar  

Cotruvo, J. A. The chemistry of lanthanides in biology: recent discoveries, emerging principles, and technological applications. ACS Cent. Sci. 5 , 1496–1506 (2019).

Article   CAS   PubMed   PubMed Central   Google Scholar  

Kostelnik, T. I. & Orvig, C. Radioactive main group and rare earth metals for imaging and therapy. Chem. Rev. 119 , 902–956 (2019).

Article   CAS   PubMed   Google Scholar  

Liddle, S. T., Mills, D. P. & Natrajan, L. S. The Lanthanides and Actinides: Synthesis, Reactivity, Properties and Applications (World Scientific Publishing Europe Ltd, 2021).

Marinsky, J. A., Glendenin, L. E. & Coryell, C. D. The chemical identification of radioisotopes of neodymium and of element 61. J. Am. Chem. Soc. 69 , 2781–2785 (1947).

Cantrill, S. Promethium puzzles. Nat. Chem. 10 , 1270–1270 (2018).

Elkina, V. & Kurushkin, M. Promethium: to strive, to seek, to find and not to yield. Front. Chem. 8 , 588 (2020).

Sasaki, Y., Sugo, Y., Suzuki, S. & Tachimori, S. The novel extractants, diglycolamides, for the extraction of lanthanides and actinides in HNO 3 – n -dodecane system. Solvent Extr. Ion Exch. 19 , 91–103 (2001).

Article   CAS   Google Scholar  

Ellis, R. J. et al. ‘Straining’ to separate the rare earths: how the lanthanide contraction impacts chelation by diglycolamide ligands. Inorg. Chem. 56 , 1152–1160 (2017).

Baldwin, A. G. et al. Outer-sphere water clusters tune the lanthanide selectivity of diglycolamides. ACS Cent. Sci. 4 , 739–747 (2018).

Cotton, S. Lanthanide and Actinide Chemistry (John Wiley & Sons, 2006).

Thiele, N. A., Fiszbein, D. J., Woods, J. J. & Wilson, J. J. Tuning the separation of light lanthanides using a reverse-size selective aqueous complexant. Inorg. Chem. 59 , 16522–16530 (2020).

Johnson, K. R., Driscoll, D. M., Damron, J. T., Ivanov, A. S. & Jansone-Popova, S. Size selective ligand tug of war strategy to separate rare earth elements. JACS Au 3 , 584–591 (2023).

Yin, X. et al. Rare earth separations by selective borate crystallization. Nat. Commun. 8 , 14438 (2017).

Sholl, D. S. & Lively, R. P. Seven chemical separations to change the world. Nature 532 , 435–437 (2016).

Article   ADS   PubMed   Google Scholar  

Wilmarth, W. R., Haire, R. G., Young, J. P., Ramey, D. W. & Peterson, J. R. Absorption spectrophotometric and X-ray diffraction studies of the trihalides of promethium in the solid state. J. Less Common Met. 141 , 275–284 (1988).

Wilson, A. S., Roberts, F. P. & Wheelwright, E. J. Promethium oxide structure. Nature 198 , 580 (1963).

Article   ADS   CAS   Google Scholar  

Weigel, F., Ollendorff, W., Scherer, V. & Hagenbruch, R. Strukturuntersuchungen an lanthanidenoxalaten. I. Einkristalluntersuchungen an neodym (III)‐oxalatdekahydrat und samarium (III)‐oxalatdekahydrat. Die elementarzelle von promethium (III)‐oxalatdekahydrat. Z. Anorg. Allg. Chem. 345 , 119–128 (1966).

Article   Google Scholar  

Weigel, F. & Scherer, V. Die chemie des promethiums: VIII. Promethium (IIΙ)-molybdat und -wolframat. Radiochim. Acta 13 , 6–10 (1970).

Parker, G. W. & Lantz, P. M. The absorption spectrum of element-61, promethium. J. Am. Chem. Soc. 72 , 2834–2836 (1950).

Meggers, W. F., Scribner, B. F. & Bozman, W. R. Absorption and emission spectra of promethium. J. Res. Nat. Bur. Stand. 46 , 85–98 (1951).

Wilmarth, W. R., Begun, G. M., Haire, R. G. & Peterson, J. R. Raman spectra of Pm 2 O 3 , PmF 3 , PmCl 3 , PmBr 3 and PmI 3 . J. Raman Spectr. 19 , 271–275 (1988).

Sheppard, J. C., Wheelwright, E. J. & Roberts, F. P. The magnetic susceptibility of promethium-147 oxide. J. Phys. Chem. 67 , 1568–1569 (1963).

Pyykko, P. Relativistic effects in structural chemistry. Chem. Rev. 88 , 563–594 (1988).

Pyykko, P. Dirac-Fock one-center calculations Part 8. The 1 Σ states of ScH, YH, LaH, AcH, TmH, LuH and LrH. Phys. Scr. 20 , 647–651 (1979).

Clark, A. E. Density functional and basis set dependence of hydrated Ln(III) properties. J. Chem. Theory Comput. 4 , 708–718 (2008).

Bagus, P. S., Lee, Y. S. & Pitzer, K. S. Effects of relativity and of the lanthanide contraction on the atoms from hafnium to bismuth. Chem. Phys. Lett. 33 , 408–411 (1975).

Kuchle, W., Dolg, M. & Stoll, H. Ab initio study of the lanthanide and actinide contraction. J. Phys. Chem. A 101 , 7128–7133 (1997).

Shannon, R. D. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr. Sect. A. Cryst. Phys. Diffr. Theor. Gen. Crystallogr. 32 , 751–767 (1976).

Article   ADS   Google Scholar  

Allen, P. G., Bucher, J. J., Shuh, D. K., Edelstein, N. M. & Craig, I. Coordination chemistry of trivalent lanthanide and actinide ions in dilute and concentrated chloride solutions. Inorg. Chem. 39 , 595–601 (2000).

Persson, I., D’Angelo, P., De Panfilis, S., Sandstrom, M. & Eriksson, L. Hydration of lanthanoid(III) ions in aqueous solution and crystalline hydrates studied by EXAFS spectroscopy and crystallography: the myth of the ‘gadolinium break’. Chem. Eur. J. 14 , 3056–3066 (2008).

D’Angelo, P. et al. Revised ionic radii of lanthanoid(III) ions in aqueous solution. Inorg. Chem. 50 , 4572–4579 (2011).

Article   PubMed   Google Scholar  

Yamaguchi, T., Nomura, M., Wakita, H. & Ohtaki, H. An extended X-ray absorption fine-structure study of aqueous rare-earth perchlorate solutions in liquid and glassy states. J. Chem. Phys. 89 , 5153–5159 (1988).

Shiery, R. C. et al. Coordination sphere of lanthanide aqua ions resolved with ab initio molecular dynamics and X-ray absorption spectroscopy. Inorg. Chem. 60 , 3117–3130 (2021).

Seitz, M., Oliver, A. G. & Raymond, K. N. The lanthanide contraction revisited. J. Am. Chem. Soc. 129 , 11153–11160 (2007).

Okumura, S., Kawasaki, T., Sasaki, Y. & Ikeda, Y. Crystal structures of lanthanoid(III) (Ln(III), Ln = Tb, Dy, Ho, Er, Tm, Yb, and Lu) nitrate complexes with N,N,N′,N′-tetraethyldiglycolamide. Bull. Chem. Soc. Jpn 87 , 1133–1139 (2014).

Brigham, D. M. et al. Trefoil-shaped outer-sphere ion clusters mediate lanthanide(III) ion transport with diglycolamide ligands. J. Am. Chem. Soc. 139 , 17350–17358 (2017).

Zasimov, P. et al. HERFD-XANES and RIXS study on the electronic structure of trivalent lanthanides across a series of isostructural compounds. Inorg. Chem. 61 , 1817–1830 (2022).

Hamalainen, K., Siddons, D. P., Hastings, J. B. & Berman, L. E. Elimination of the inner-shell lifetime broadening in X-ray absorption spectroscopy. Phys. Rev. Lett. 67 , 2850–2853 (1991).

Kvashnina, K. O., Butorin, S. M. & Glatzel, P. Direct study of the f-electron configuration in lanthanide systems. J. Anal. Atom Spectrom. 26 , 1265–1272 (2011).

Waldron, K. A., Fehringer, E. M., Streeb, A. E., Trosky, J. E. & Pearson, J. J. Screening percentages based on Slater effective nuclear charge as a versatile tool for teaching periodic trends. J. Chem. Educ. 78 , 635–639 (2001).

Pagano, J. K. et al. Actinide 2-metallabiphenylenes that satisfy Huckel’s rule. Nature 578 , 563 (2020).

Ferrier, M. G. et al. Spectroscopic and computational investigation of actinium coordination chemistry. Nat. Commun. 7 , 12312 (2016).

Goodwin, C. A. P. et al. Isolation and characterization of a californium metallocene. Nature 599 , 421–424 (2021).

Silver, M. A. et al. Characterization of berkelium(III) dipicolinate and borate compounds in solution and the solid state. Science 353 , aaf3762 (2016).

Poe, T. N. et al. Isolation of a californium(II) crown-ether complex. Nat. Chem. 15 , 722–728 (2023).

Carter, K. P. et al. Structural and spectroscopic characterization of an einsteinium complex. Nature 590 , 85–88 (2021).

Mayes, R. T. et al. Combination of DGA and LN columns: a versatile option for isotope production and purification at Oak Ridge National Laboratory. Solvent Extr. Ion Exch. 39 , 166–183 (2021).

Weaver, B. & Kappelmann, F. A. TALSPEAK: A New Method of Separating Americium and Curium from the Lanthanides by Extraction from an Aqueous Solution of an Aminopolyacetic Acid Complex with a Monoacetic Organophosphate or Phosphonate. ORNL– 3559 (Oak Ridge National Laboratory, 1964).

Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12 , 537–541 (2005).

Kresse, G. & Furthmuller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comp. Mater. Sci. 6 , 15–50 (1996).

Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47 , 558–561 (1993).

Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50 , 17953–17979 (1994).

Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59 , 1758–1775 (1999).

Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77 , 3865–3868 (1996).

Grimme, S., Antony, J., Ehrlich, S. & Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT-D) for the 94 elements H-Pu. J. Chem. Phys. 132 , 154104 (2010).

Sun, H., Mumby, S. J., Maple, J. R. & Hagler, A. T. An ab initio CFF93 all-atom force field for polycarbonates. J. Am. Chem. Soc. 116 , 2978–2987 (1994).

MedeA(R)-2.20; Materials Design, Inc. (Angel Fire, 2016).

Plimpton, S. Fast parallel algorithms for short-range molecular dynamics. J. Comput. Phys. 117 , 1–19 (1995).

Nose, S. A Unified formulation of the constant temperature molecular dynamics methods. J. Chem. Phys. 81 , 511–519 (1984).

Hoover, W. G. Canonical dynamics: equilibrium phase-space distributions. Phys. Rev. A 31 , 1695–1697 (1985).

Rehr, J. J., Kas, J. J., Vila, F. D., Prange, M. P. & Jorissen, K. Parameter-free calculations of X-ray spectra with FEFF9. Phys. Chem. Chem. Phys. 12 , 5503–5513 (2010).

Gaussian 16, Revision A.03 (Gaussian Inc., 2016).

Dunning, T. H. Jr. Gaussian basis sets for use in correlated molecular calculations. I. The atoms boron through neon and hydrogen. J. Chem. Phys. 90 , 1007–1023 (1989).

Dolg, M., Stoll, H. & Preuss, H. Energy‐adjusted ab initio pseudopotentials for the rare earth elements. J. Chem. Phys. 90 , 1730–1734 (1989).

Adamo, C. & Barone, V. Toward reliable density functional methods without adjustable parameters: the PBE0 model. J. Chem. Phys. 110 , 6158–6170 (1999).

Neese, F. The ORCA program system. Wires Comput. Mol. Sci. 2 , 73–78 (2012).

Roemelt, M. & Neese, F. Excited states of large open-shell molecules: an efficient, general, and spin-adapted approach based on a restricted open-shell ground state wave function. J. Phys. Chem. A 117 , 3069–3083 (2013).

Kubas, A., Verkamp, M., Vura-Weis, J., Neese, F. & Maganas, D. Restricted open-shell configuration interaction singles study on M- and L-edge X-ray absorption spectroscopy of solid chemical systems. J. Chem. Theory Comput. 14 , 4320–4334 (2018).

Becke, A. D. Density-functional exchange-energy approximation with correct asymptotic-behavior. Phys. Rev. A 38 , 3098–3100 (1988).

Plasser, F., Wormit, M. & Dreuw, A. New tools for the systematic analysis and visualization of electronic excitations. I. Formalism. J. Chem. Phys. 141 , 024106 (2014).

Glendening, E. D., Landis, C. R. & Weinhold, F. Natural bond orbital methods. Wires Comput. Mol. Sci. 2 , 1–42 (2012).

NBO v.7.0 (Theoretical Chemistry Institute, Univ. Wisconsin, 2018).

Glendening, E. D., Landis, C. R. & Weinhold, F. NBO 7.0: new vistas in localized and delocalized chemical bonding theory. J. Comput. Chem. 40 , 2234–2241 (2019).

Pettersen, E. F. et al. UCSF Chimera—a visualization system for exploratory research and analysis. J. Comput. Chem. 25 , 1605–1612 (2004).

66santanu/FEFF-Input-MD-EXAFS: Create_FEFF_Input. Zenodo https://doi.org/10.5281/zenodo.10045182 (2023).

Download references

Acknowledgements

This research was supported by the US Department of Energy (DOE), Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division and Materials Sciences and Engineering Division under award number DE-SC00ERKCG21 (D.M.D., S.P., S.R., S.J.-P. and A.S.I.); the DOE Isotope Programme, managed by the Office of Science for Isotope R&D and Production (F.D.W., R.T.M., L.H.D., S.K.C., T.D., A.M., M.S., S.M.V., S.M.D. and I.P.); and the DOE, Office of Science, Office of Basic Energy Sciences, Chemical Sciences, Geosciences, and Biosciences Division under award number DE-SC00 ERKCC08 (J.D.E.). Use of the NSLS-II (NIST beamline 6-BM) was supported by the DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract no. DE-SC0012704. This research used resources of the Oak Ridge Leadership Computing Facility (OLCF) and the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the DOE under contract no. DE-AC05-00OR22725. This research used the hot cells and glovebox laboratories and other resources of the Radiochemical Engineering Development Centre, a DOE Office of Science research facility operated by the Oak Ridge National Laboratory. D.M.D., B.R., I.P. and A.S.I. thank K. Wehunt of Brookhaven National Laboratory for her help with handling radioactive samples at NSLS-II and E. Jahrman of the National Institute of Standards and Technology for critically reading the manuscript and providing helpful suggestions. I.P. and A.S.I. thank R. Copping, L. Harvey, N. Sims and M. Du for helpful discussions.

Author information

Authors and affiliations.

Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA

Darren M. Driscoll, Subhamay Pramanik, Jeffrey D. Einkauf, Santanu Roy, Thomas Dyke, Santa Jansone-Popova, Ilja Popovs & Alexander S. Ivanov

Radioisotope Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA

Frankie D. White, Richard T. Mayes, Lætitia H. Delmau, Samantha K. Cary, April Miller, Matt Silveira, Shelley M. VanCleve & Sandra M. Davern

National Institute of Standards and Technology, Gaithersburg, MD, USA

Bruce Ravel

National Center for Computational Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, USA

Dmytro Bykov

You can also search for this author in PubMed   Google Scholar

Contributions

I.P., A.S.I. and S.J.-P. acquired funding. I.P. and A.S.I. conceived and led the project, conceptualized the study and wrote the first draft. S.P., S.J.-P. and I.P. synthesized the ligand. F.D.W., R.T.M., L.H.D., S.K.C., T.D., A.M., M.S., S.M.V. and S.M.D. produced, purified and prepared the Pm XAS sample. S.P. and D.M.D. prepared non-radioactive lanthanide samples. D.M.D. and A.S.I. acquired XAS beamtime at NSLS-II. D.M.D., B.R. and A.S.I. designed and conducted XAS experiments. D.M.D. analysed, fitted and summarized XAS data. S.P. obtained single crystals of Ln-PyDGA complexes. J.D.E. collected and refined single-crystal X-ray diffraction crystallographic data. A.S.I. and D.B. acquired computational time on the OLCF. A.S.I. performed and interpreted AIMD simulations and chemical bonding analysis. S.R. simulated AIMD-EXAFS and XANES spectra using FEFF9. D.B. performed and interpreted XANES calculations using DFT–ROCIS. All authors discussed the results and contributed to the final manuscript.

Corresponding authors

Correspondence to Ilja Popovs or Alexander S. Ivanov .

Ethics declarations

Competing interests.

The authors declare no competing interests.

Peer review

Peer review information.

Nature thanks Kristina Kvashnina and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data figures and tables

Extended data fig. 1 pm sample preparation and transportation steps for x-ray absorption spectroscopy measurements..

a , (left) 147 Pm(NO 3 ) 3  ∙ nH 2 O (n < 9) solid residue; (middle) 70 mM 0.01 HNO 3 147 Pm(NO 3 ) 3 stock solution; (right) 147 Pm-PyDGA sample being epoxied before removal from glovebox. b , (left) fully sealed Kapton capillary with solution of 147 Pm-PyDGA; (middle) capillary sealed within one polypropylene bag; (right) capillary sealed within two polypropylene bags. c , Shipping preparations: (left) folded triple bagged Kapton capillary with solution of 147 Pm-PyDGA inside pipe nipple along with absorbent material; (middle) folding in of absorbent material for cap placement; (right) cap hand tightened, and then radiological label applied. d , Shipping preparations: (left) pipe nipple wrapped in absorbent material and then placed inside of cardboard insert; (middle) cardboard insert put inside of 5-gal drum along with absorbent packaging material; (right) wire looped through drum ring. e , (left) demonstration of empty capillary within polypropylene bag held by the aluminium sample holder designed for the 147 Pm-PyDGA measurements; (middle) 3D drawing of the sample holder used for the 147 Pm-PyDGA measurements; (right) the Pm sample photograph from the beamline camera taken during XAS measurements.

Extended Data Fig. 2 L 1 -edge XAS data for the [Pm(PyDGA) 3 ] 3+ complex in solution at room temperature.

a , Pm L 1 -edge XANES spectrum (black line). b-c , Pm EXAFS data (squares) and the fit (pink line). ( b ) L 1 -edge EXAFS spectrum of the Pm complex where k is the energy of the photoelectron in wavenumbers and k 3 χ( k ) is the k 3 -weighted EXAFS function. ( c ) Magnitude of the Fourier transform (black squares) and the real component of the Fourier transformed EXAFS data (empty squares).

Extended Data Fig. 3 Comparison of L 3 -edge XANES data for the selected lanthanide [Ln(PyDGA) 3 ] 3+ complexes in solution and Pm L 3 -edge XANES spectrum and its interpretation using DFT/ROCIS and multiple scattering (FEFF9) calculations.

a , Nd III and Sm III spectra are compared to the Pm III data, confirming the +3 oxidation state. The energy separation between the white line (II) and the first postedge feature (III) decreases, whereas the energy separation between the white line (II) and the second postedge peak (IV) increases across the Ln series. The obtained trend is consistent with a previous study 39 using HERFD-XANES, where the shift to higher energies of peak IV was attributed to lanthanide contraction (shortening of the inner-sphere bonds across the Ln series). The plot is presented as a function of Δ E (the difference between the photon energy E and the peak in the first derivative of the data E 0 ). The spectra are scaled to the same maximum height and offset for clarity. Dashed lines are guides to the eye. b , Experimental (black line) and simulated XANES spectra using DFT/ROCIS calculations (circles) with the representative orbitals participating in the core electron excitations, which correspond to different regions of the XANES spectrum. Band assignment was performed based on natural difference orbitals (NDOs), drawn with 0.03 au isosurface value. Only the acceptor NDOs are visualized. c , Comparison of experimental (black line) and simulated XANES spectra using FEFF9 calculations (circles) with the projected density of states (PDOS) related to the Pm III d and f orbital contributions. To compare the results on a common energy scale, the maximum of the absorption edge has been set to zero. The spectra are offset for clarity.

Extended Data Fig. 4 X-ray crystal structures of the Pm surrogate [Sm(PyDGA) 3 ][Sm(NO 3 ) 6 ]·3C 2 H 5 OH and [Er(PyDGA) 3 ] 2 [Er(NO 3 ) 5 ] 3 ·2H 2 O complexes.

a , Thermal ellipsoid plot (50% probability level) of [Sm(PyDGA) 3 ][Sm(NO 3 ) 6 ]·3C 2 H 5 OH crystals (CCDC:2279633). Hydrogen atoms and solvents are omitted for clarity. b , Thermal ellipsoid plot (50% probability level) of [Er(PyDGA) 3 ] 2 [Er(NO 3 ) 5 ] 3 ·2H 2 O crystals (CCDC: 2279634). Hydrogen atoms are omitted for clarity.

Extended Data Fig. 5 Structural parameters for the [Pm(PyDGA) 3 ] 3+ complex in aqueous solution obtained from AIMD simulations.

Radial distribution function ( g ( r ); red curve, left axis) and its integration (coordination number, CN; blue curve, right axis) of ( a ) oxygen atoms, including PyDGA donor atoms and water molecules, ( b ) PyDGA carbon atoms, and ( c ) PyDGA nitrogen atoms around Pm III . Water structuring around the complex at 4.43 Å can be observed due to transient hydrogen bond interactions with the O donor groups of PyDGA ligands. As can be seen, the amide carbonyl and etheric Pm–O bonds could not be resolved at room temperature due to their dynamic nature in solution. However, the simulations show distinct Pm–C correlations with the peaks corresponding to the sp 3 - and sp 2 -C positions relative to Pm III , pointing to their more rigid behavior upon complexation. The AIMD average bond lengths (Pm–O distance of 2.48 Å and Pm–C distance of 3.44 Å) agree well with the results of static DFT calculations (Pm–O distance of 2.47 Å and Pm–C distance of 3.44 Å) and the EXAFS data in Extended Data Table 1 .

Extended Data Fig. 6 EXAFS data (squares) and the fit (red line) for the entire set of isostructural [Ln(PyDGA) 3 ] 3+ complexes in solution.

a , L 3 -edge EXAFS spectra of the lanthanide complexes in solution where k is the energy of the photoelectron in wavenumbers and k 3 χ( k ) is the k 3 -weighted EXAFS function. The apparent features in the experimental EXAFS data at approximately 5.7 Å −1 to 6.0 Å −1 for the light lanthanides are due to multi-electron excitations. b , The real component of the Fourier transformed EXAFS data and corresponding fits for the lanthanide complexes, indicating shortening of the average first-shell distance across the Ln series.

Extended Data Fig. 7 Plot of the Ln–O bond distances against the number of 4  f electrons, with the quadratic fit shown as a red line.

The obtained parameters ( b  = -0.02053 and c  = 0.000350921) and a value for \({Z}_{0}^{* }\)  = 15.42 (5 p electrons) were used to calculate the shielding constant for f electrons ( s  = 0.74), based on the modified Slater model 36 . 1 σ error bars in Ln–O bond distance are computed from the covariance matrix of the non-linear minimization of the EXAFS fit 49 .

Extended Data Fig. 8 PyDGA characterization.

a , 1 H NMR spectrum of PyDGA in CDCl 3 . 1 H NMR (400 MHz, CDCl 3 ) δ H 4.17 (s, 4H), 3.39 (t, J  = 6.9 Hz, 4H), 3.34 (t, J  = 6.8 Hz, 4H), 1.87 (p, J  = 6.8 Hz, 4H), 1.76 (p, J  = 6.6 Hz, 4H). b , 13 C NMR spectrum of PyDGA in CDCl 3 . 13 C NMR (101 MHz, CDCl 3 ) δ C 167.54, 69.83, 45.86, 45.57, 26.21, 23.95. c , FT-IR spectrum of PyDGA. 2880 (C-H), 1645 (C = O), 1150 (C-O). d , ESI-MS ( + Ve) spectrum showing the molecular ion peaks (m/z, Daltons) 241.1 [M + H] + ; 263.1 [M+Na] + ; 503.4 [2 M+Na] + of PyDGA using Advion expression compact Mass Spectrometer. Exact mass for [C 12 H 20 N 2 O 3 ] was M = 240.1 Daltons.

Supplementary information

Peer review file, supplementary video 1.

Video showing the molecular dynamics of the PyDGA ligand–Pm interactions in an aqueous environment. H atoms on the ligand are not shown. Only the nearest water molecules within 5 Å from the metal centre are visualized for clarity

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ .

Reprints and permissions

About this article

Cite this article.

Driscoll, D.M., White, F.D., Pramanik, S. et al. Observation of a promethium complex in solution. Nature 629 , 819–823 (2024). https://doi.org/10.1038/s41586-024-07267-6

Download citation

Received : 17 October 2023

Accepted : 04 March 2024

Published : 22 May 2024

Issue Date : 23 May 2024

DOI : https://doi.org/10.1038/s41586-024-07267-6

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

This article is cited by

Element from the periodic table’s far reaches coaxed into elusive compound.

• Mark Peplow

Nature (2024)

By submitting a comment you agree to abide by our Terms and Community Guidelines . If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Quick links

• Explore articles by subject
• Guide to authors
• Editorial policies

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Breakthrough discovery uses engineered surfaces to shed heat

When it comes to cooling equipment like nuclear reactors, every degree counts.

Splash a few drops of water on a hot pan and if the pan is hot enough, the water will sizzle and the droplets of water seem to roll and float, hovering above the surface.

The temperature at which this phenomenon, called the Leidenfrost effect, occurs is predictable, usually happening above 230 degrees Celsius. The team of Jiangtao Cheng, associate professor in the Virginia Tech Department of Mechanical Engineering, has discovered a method to create the aquatic levitation at a much lower temperature, and the results have been published in Nature Physics. Alongside first author and Ph.D. student Wenge Huang, Cheng's team collaborated with Oak Ridge National Lab and Dalian University of Technology for sections of the research.

The discovery has great potential in heat transfer applications such as the cooling of industrial machines and surface fouling cleaning for heat exchangers. It also could help prevent damage and even disaster to nuclear machinery.

Currently, there are more than 90 licensed operable nuclear reactors in the U.S. that power tens of millions of homes, anchor local communities, and actually account for half of the country's clean energy electricity production. It requires resources to stabilize and cool those reactors, and heat transfer is crucial for normal operations.

The physics of hovering water

For three centuries, the Leidenfrost effect has been a well-known phenomenon among physicists that establishes the temperature at which water droplets hover on a bed of their own vapor. While it has been widely documented to start at 230 degrees Celsius, Cheng and his team have pushed that limit much lower.

The effect occurs because there are two different states of water living together. If we could see the water at the droplet level, we would observe that all of a droplet doesn't boil at the surface, only part of it. The heat vaporizes the bottom, but the energy doesn't travel through the entire droplet. The liquid portion above the vapor is receiving less energy because much of it is used to boil the bottom. That liquid portion remains intact, and this is what we see floating on its own layer of vapor. This has been referred to since its discover in the 18th century as the Leidenfrost effect, named for German physician Johann Gottlob Leidenfrost.

That hot temperature is well above the 100 degree Celsius boiling point of water because the heat must be high enough to instantly form a vapor layer. Too low, and the droplets don't hover. Too high, and the heat will vaporize the entire droplet.

New work at the surface

The traditional measurement of the Leidenfrost effect assumes that the heated surface is flat, which causes the heat to hit the water droplets uniformly. Working in the Virginia Tech Fluid Physics Lab, Cheng's team has found a way to lower the starting point of the effect by producing a surface covered with micropillars.

"Like the papillae on a lotus leaf, micropillars do more than decorate the surface, said Cheng. "They give the surface new properties."

The micropillars designed by Cheng's team are 0.08 millimeters tall, roughly the same as the width of a human hair. They are arranged in a regular pattern of 0.12 millimeters apart. A droplet of water encompasses 100 or more of them. These tiny pillars press into a water droplet, releasing heat into the interior of the droplet and making it boil more quickly.

Compared to the traditional view that the Leidenfrost effect triggers at 230 degrees Celsius, the fin-array-like micropillars press more heat into the water than a flat surface. This causes microdroplets to levitate and jump off the surface within milliseconds at lower temperatures because the speed of boiling can be controlled by changing the height of the pillars.

Lowering the limits of Leidenfrost

When the textured surface was heated, the team discovered that the temperature at which the floating effect was achieved was significantly lower than that of a flat surface, starting at 130 degrees Celsius.

Not only is this a novel discovery for the understanding of the Leidenfrost effect, it is a twist on the limits previously imagined. A 2021 study from Emory University found that the properties of water actually caused the Leidenfrost effect to fail when the temperature of the heated surface lowers to 140 degrees. Using the micropillars created by Cheng's team, the effect is sustainable even 10 degrees below that.

"We thought the micropillars would change the behaviors of this well-known phenomenon, but our results defied even our own imaginations," said Cheng. "The observed bubble-droplet interactions are a big discovery for boiling heat transfer."

The Leidenfrost effect is more than an intriguing phenomenon to watch, it is also a critical point in heat transfer. When water boils, it is most efficiently removing heat from a surface. In applications such as machine cooling, this means that adapting a hot surface to the textured approach presented by Cheng's team gets heat out more quickly, lowering the possibility of damages caused when a machine gets too hot.

"Our research can prevent disasters such as vapor explosions, which pose significant threats to industrial heat transfer equipment," said Huang. "Vapor explosions occur when vapor bubbles within a liquid rapidly expand due to the present of intense heat source nearby. One example of where this risk is particularly pertinent is in nuclear plants, where the surface structure of heat exchangers can influence vapor bubble growth and potentially trigger such explosions. Through our theoretical exploration in the paper, we investigate how surface structure affects the growth mode of vapor bubbles, providing valuable insights into controlling and mitigating the risk of vapor explosions."

Another challenge addressed by the team is the impurities fluids leave behind in the textures of rough surfaces, posing challenges for self-cleaning. Under spray cleaning or rinsing conditions, neither conventional Leidenfrost nor cold droplets at room temperature can fully eliminate deposited particulates from surface roughness. Using Cheng's strategy, the generation of vapor bubbles is able to dislodge those particles from surface roughness and suspend them in the droplet. This means that the boiling bubbles can both move heat and impurities away from the surface.

• Nature of Water
• Thermodynamics
• Nuclear Energy
• Spintronics
• Severe Weather
• Environmental Issues
• Lake effect snow
• Speed of sound
• Temperature
• Solar panel
• Surface tension

Story Source:

Materials provided by Virginia Tech . Original written by Alex Parrish. Note: Content may be edited for style and length.

Journal Reference :

• Wenge Huang, Lei Zhao, Xukun He, Yang Li, C. Patrick Collier, Zheng Zheng, Jiansheng Liu, Dayrl P. Briggs, Jiangtao Cheng. Low-temperature Leidenfrost-like jumping of sessile droplets on microstructured surfaces . Nature Physics , 2024; DOI: 10.1038/s41567-024-02522-z

Cite This Page :

Explore More

• Cold Supply Chains for Food: Huge Savings
• Genetic Mosaicism More Common Than Thought
• How Killifish Embryos Survive 8 Month Drought
• Simple Food Swaps to Cut Greenhouse Gases
• Fossil Porcupine in a Prickly Dilemma
• Future Climate Impacts Put Whale Diet at Risk
• Charge Your Laptop in a Minute?
• Caterpillars Detect Predators by Electricity
• 'Electronic Spider Silk' Printed On Human Skin
• Engineered Surfaces Made to Shed Heat

Trending Topics

Strange & offbeat.

Quick links

• Climate change
• COVID-19 research
• Staff profiles

GenCost: cost of building Australia’s future electricity needs

Each year, CSIRO and the Australian Energy Market Operator (AEMO) collaborate with industry stakeholders to update GenCost. This leading economic report estimates the cost of building new electricity generation, storage, and hydrogen production in Australia out to 2050.

GenCost 2023-24 report released

The latest release was shaped by an unprecedented level of industry participation.

What’s new?

• Renewables (solar and wind + firming) remains the lowest cost new build electricity technology.
• Large-scale nuclear technology costs included for the first time.
• Future wind costs revised upwards.
• An extensive FAQ section addressing common questions from current and past consultations.

What is GenCost?

GenCost is a leading economic report for business leaders and decision-makers planning reliable and affordable energy solutions to achieve net zero emissions by 2050.

Published annually in collaboration with the Australian Energy Market Operator (AEMO), GenCost offers accurate, policy and technology-neutral cost estimates for new electricity generation, storage, and hydrogen technologies, through to 2050.

GenCost is highly collaborative and transparent, leveraging the expertise of energy industry stakeholders and involving extensive consultation to ensure accuracy prior to publication.

Transcript to be supplied

CSIRO is committed to ensuring its online content is accessible to everyone regardless of ability.

Request accessibility assistance

• View transcript
• Copy embed code

Share & embed this video

https://vimeo.com/896412073?share=copy

<iframe src="//player.vimeo.com/video/896412073?share=copy" width="640" height="360" frameborder="0" allow="autoplay; fullscreen" allowfullscreen></iframe>

GenCost 2023-24 report

Explore key insights from the latest report.

GenCost projects the cost of electricity generation and storage for a wide range of technologies up to the year 2050.  

Renewables remain lowest cost

The report highlights wind power’s slower recovery from global inflationary pressures, resulting in upward revisions for both onshore and offshore wind costs over the next decade.

Despite this, updated analysis reaffirms that renewables, including associated storage and transmission costs, remain the lowest cost, new build technology out to 2050.

This competitive position reflects a decade of cost reductions in wind, solar photovoltaics (PV) and batteries before the pandemic. This is in contrast with costs of mature competitors which have remained flat.

Large-scale nuclear costs introduced

The inclusion of large-scale nuclear costs this year was prompted by increased stakeholder interest in nuclear technology following the updated cost estimates for SMRs in the 2023-24 consultation draft.

Applying overseas costs to large-scale nuclear projects in Australia is complex due to the lack of a domestic nuclear industry and significant global differences in labor costs, workforce expertise, governance, and standards. The GenCost 2023-24 report team estimated large-scale nuclear costs using South Korea’s successful nuclear program. They adjusted for differences in Australian and South Korean deployment costs by comparing the cost ratio of new coal generation in each country. GenCost found nuclear power to be more expensive than renewables and estimated a development timeline of at least 15 years, including construction. This reflects the absence of a local development pipeline, additional legal, safety and security requirements, and stakeholder evidence. Achieving the reported nuclear costs depends on Australia committing to a continuous building program like South Korea’s. Initial units are likely to incur higher costs, and a first-of-a-kind premium of up to 100 per cent is possible, although not included in the cost estimates for nuclear or other new electricity technologies in the report.

Explore answers to commonly asked questions about GenCost.

• 2023-24 GenCost report
• 2023-24 GenCost media release
• 2023-24 GenCost infographics
• 2023-24 GenCost report (text version)
• GenCost project data and previous reports

Our in-depth explainers take a closer look at Australia’s evolving electricity sector. What are the challenges and opportunities that lie ahead in Australia's energy transition?

Understanding the cost of Australia's energy transition

Understanding the costs of new-build electricity generation technologies is essential if we are to evolve Australia’s energy system to limit emissions.

The question of nuclear in Australia’s energy sector

In Australia's transition to net zero emissions, the electricity sector has a major role to play. But does nuclear power have a place in our future grid?

Latest news

There are no news releases to show.

Find out how we can help you and your business. Get in touch using the form below and our experts will get in contact soon!

CSIRO will handle your personal information in accordance with the Privacy Act 1988 (Cth) and our Privacy Policy .

Enter a valid email address, for example [email protected]

A Country value must be provided

First name must be filled in

Surname must be filled in

Please choose an option

Organisation must be filled in

Please provide a subject for the enquriy

We'll need to know what you want to contact us about so we can give you an answer

We have received your enquiry and will reply soon.

We're Sorry

The contact form is currently unavailable. Please try again later. If this problem persists, please call us with your enquiry on 1300 363 400 or +61 3 9545 2176. We are available from 9.00 am to 4.00 pm AEST Monday - Friday.

Our Privacy and Cookies Policy

We use cookies to provide the best experience for you. To find out more check our cookies and privacy policy

Nucleareurope calls for expansion of EU hydrogen output

22 May 2024

Nuclear trade body Nucleareurope has highlighted the benefits of European-based hydrogen production from nuclear energy in a new position paper.

Nucleareurope noted a recent survey by McKinsey found that intensive gas buyers expect to reduce their gas demand in the future, largely by switching to hydrogen or synthetic gases produced via hydrogen.

"For the time being, the European Commission's focus is primarily on hydrogen produced exclusively from renewables, with a significant share of this hydrogen being imported from third countries, notably from the global south," the position paper says. "This will result in an important increase in energy demand due to transportation and losses while potentially exploiting countries where energy poverty is high and affecting Europe's energy sovereignty by creating a dependency on imported renewable hydrogen."

The European Commission's REPowerEU plan - adopted in May 2022 to rapidly reduce EU dependence on Russian fossil fuels - foresaw 10 million tonnes of domestic hydrogen production complemented with 6-10 million tonnes of imported hydrogen by 2030. However, following the communication in February this year on the 2040 climate targets, this plan has been downsized to 3 million tonnes, "perhaps to align it with the realistic forecasts of domestic production via renewables," Nucleareurope said.

"This is where other low-carbon energy sources, such as nuclear, could fill the gap and help meet the original ambitions, as the main target remains unchanged: net-zero by 2050," it added.

According to Nucleareurope, the main advantage of hydrogen production via nuclear is that the load factor of the installed electrolysers will be maximised with baseload production - possibility to reach 8000 hours per year with nuclear and improve the lifetime and payback of the installation.

One existing nuclear power plant with a capacity of 1000 MWe and a capacity factor of over 90%, coupled with 1000 MW of electrolysers, could produce about 0.16 million tonnes of low-carbon hydrogen per year, providing an uninterrupted supply to end-users, it noted. This output could increase further by up to 20% if coupled with high-temperature electrolysers capable of using nuclear steam.

In order to support the deployment of domestic hydrogen production, Nucleareurope recommends that the EU focus on: encouraging a diversified approach to hydrogen production that recognises the potential of all net-zero technologies; emphasising the importance of energy sovereignty in the context of hydrogen production; developing policies to support the growth of domestic hydrogen industries, recognising their role in reindustrialisation and job creation; advocating for strategic investments in infrastructure that support domestic hydrogen production, storage and distribution; and allocating resources for research and development initiatives focused on improving the efficiency and cost-effectiveness of hydrogen production technologies, including nuclear-based methods.

"Domestic production of hydrogen can help solve some of the challenges which the EU is facing in terms of energy security, environmental sustainability, and economic competitiveness" said Nucleareurope Director General Yves Desbazeille. "Reimagining how hydrogen, a versatile and clean energy carrier, can play an important leading role in transforming the energy system is key in this respect."

Researched and written by World Nuclear News

Related topics

Tackling microplastics in antarctica using nuclear tech - chile and iaea sign mou, italy sees role for nuclear in hitting climate goals , says minister, large-scale nuclear included in australian cost report, google, microsoft and nucor team up on clean energy development, grid challenges add to need for more nuclear , wec side-event told, doe releases community guide on coal-to-nuclear conversion, nuclear output to reach new record by 2025 , says iea, indian net-zero will need nuclear, report finds.

WNN is a public information service of World Nuclear Association

Related Stories

Related information, related links.