Fast reactors
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| Fast reactors | |
|---|---|
| Name | Fast reactors |
| Type | Nuclear reactor |
| Fuel | Mixed oxide, metallic, nitride |
| Moderator | None |
| Coolant | Liquid sodium, lead, lead-bismuth, gas |
| Status | Operational, Experimental, Decommissioned, Planned |
Fast reactors are a class of nuclear reactors that operate with a neutron energy spectrum dominated by high-energy (fast) neutrons rather than thermalized neutrons. They are central to strategies for efficient fissile material utilization, plutonium management, and closing nuclear fuel cycles pursued by institutions such as the International Atomic Energy Agency, World Nuclear Association, Rosatom, Idaho National Laboratory, and national programs in France, Russia, United States, Japan, China, and India. Fast reactors interface with fuel fabrication facilities, reprocessing plants, and repository programs including initiatives by European Commission, Oak Ridge National Laboratory, and Commissariat à l'énergie atomique et aux énergies alternatives.
Introduction
Fast reactors were developed in the context of mid-20th century projects like Manhattan Project-era research, BORAX experiments, and Cold War programs such as Project Pluto and efforts at Argonne National Laboratory. Early commercial and prototype systems include installations at Dounreay, Phénix, Superphénix, BN-350, BN-600, and Monju. Key organizations in development history are United Kingdom Atomic Energy Authority, Power Reactor and Nuclear Fuel Development Corporation, Kurchatov Institute, and the Comisión Nacional de Energía Atómica.
Design and Technology
Fast reactor designs eliminate moderators used in designs like Magnox and Pressurized Water Reactor to avoid slowing neutrons; they instead rely on coolants such as liquid sodium used in EBR-II, Sodium-cooled Fast Reactor programs, lead or lead-bismuth eutectic in SVBR-100 and BREST concepts, and high-pressure helium in gas-cooled fast prototypes. Structural and materials research is driven by laboratories including Oak Ridge National Laboratory, Bundeswehr University Munich collaborations, CEA, and Japan Atomic Energy Agency, focusing on irradiation effects, swelling, and creep in alloys such as 316 stainless steel, ferritic-martensitic steels, and innovative oxide dispersion-strengthened alloys developed at MIT and University of Cambridge. Core layouts range from compact pool-type vessels as in Monju to loop-type systems like Phénix; neutronics and thermal-hydraulics modeling employs codes from Argonne National Laboratory, CEA, IAEA CRP efforts, and software frameworks originating at Los Alamos National Laboratory.
Fuel Cycle and Fuel Types
Fast reactors accommodate diverse fuels: mixed oxide fuel (MOX) containing plutonium and uranium studied at La Hague and Sellafield, metallic fuels pursued at ANL and in EBR-I/EBR-II tests, nitride fuels investigated by Kurchatov Institute and JAEA, and carbide fuels researched by Oak Ridge National Laboratory and CEA. They enable breeding of fissile isotopes (conversion of U-238 to Pu-239) and support transmutation strategies for long-lived minor actinides like Np-237, Am-241, and Cm-244—topics of programs at European Commission facilities, JRC, and multinational initiatives such as GIF and OECD NEA. Reprocessing technologies include PUREX used at La Hague and advanced pyroprocessing developed by Argonne National Laboratory and KAERI in South Korea.
Safety and Passive Features
Passive safety approaches in fast reactors draw on features demonstrated in EBR-II tests, sodium-cooled natural circulation designs in PRISM proposals, and in-service experience from BN-600. Decay heat removal strategies leverage natural convection within pool-type vessels as tested at Phénix and modeled by research groups at University of California, Berkeley and Imperial College London. Sodium chemistry understanding informed by lessons from Monju incidents is supported by teams at Cadarache and KIT. Containment and safeguard measures interact with international regimes like Non-Proliferation Treaty commitments and IAEA safeguards protocols administered by the IAEA Department of Safeguards.
Advantages and Challenges
Advantages highlighted by proponents such as Rosatom and CEA include improved fuel utilization compared with thermal reactors like BWR and PHWR, potential for reduction of high-level waste inventories advocated by OECD NEA studies, and proliferation-resistant fuel cycles explored by GIF task forces. Challenges include materials degradation under high fast-fluence conditions studied at INES and ITER-adjacent facilities, coolant chemistry hazards documented in Monju reports, high capital costs noted in evaluations by World Nuclear Association and International Energy Agency, and licensing complexity encountered by US NRC and ONR in the UK. Public acceptance debates have involved stakeholders such as Greenpeace and national parliaments including French National Assembly.
Global Development and Operational Reactors
Operational fast reactors and prototypes include BN-600 and BN-800 at Beloyarsk Nuclear Power Station managed by Rosenergoatom, CEFR in China at China Institute of Atomic Energy, and historical units like Superphénix and Phénix in France. Experimental reactors such as EBR-II at Argonne-West contributed to the Integral Fast Reactor concept supported by US Department of Energy programs, while Monju in Japan and Dounreay Fast Reactor in Scotland demonstrated practical challenges. Current projects include deployment plans by Rosatom for BN series, China National Nuclear Corporation initiatives, India’s Prototype Fast Breeder Reactor at Kalpakkam managed by Indira Gandhi Centre for Atomic Research, and collaborative efforts under Generation IV International Forum.
Future Prospects and Research Directions
Future research priorities are coordinated through frameworks like Generation IV International Forum, OECD NEA, and bilateral agreements between France and India, Russia and China. Key directions include advanced fuels developed at Oak Ridge National Laboratory and CEA, passive safety validation in testbeds at Idaho National Laboratory, advanced reprocessing methods by KAERI and RIAR, and deployment models assessed by International Energy Agency scenarios. Demonstration programs funded by entities such as European Commission Horizon 2020 and national ministries in Japan, United States Department of Energy, and Ministry of Atomic Energy of the Russian Federation aim to resolve economics, licensing, and supply-chain integration issues with industrial partners like EDF, Mitsubishi Heavy Industries, and Westinghouse.