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Technical Working Group on Fast Reactors (TWG-FR)

The Technical Working Group on Fast Reactors (TWG-FR) is a group of international experts who provide advice and support IAEA programme implementation in the area of advanced technologies and research and development (R&D) for fast reactors and sub-critical hybrid systems for energy production and for utilization/transmutation of long-lived nuclides.

The first IAEA technical working group, TWG-FR was established in 1967, as the keystone of IAEA activities in the field of fast reactor technology development. For over 50 years, the IAEA has been serving interested Member States as a focal point for information exchange, and collaborative research and technology development for fast reactors.

The members of the TWG-FR are appointed by the IAEA Deputy Director General and Head of the Department of Nuclear Energy, following consultation with the respective national authorities or organizations.

Scope and Functions

The TWG-FR assists in formulating an international vision applicable to current and advanced fast reactors, and to sub-critical hybrid systems (e.g., accelerator driven systems and fusion/fission systems), including improved economics, which is fundamental to all successful technology advances; sustainable development, in which resource utilization and waste management strategies lead to advanced fuel cycles, including those based on the full utilization of natural uranium and also thorium; and enhanced safety, by maintaining current high safety levels with increased design simplification, and passive safety systems.

The scope of the TWG-FR is broad, covering all technical aspects of R&D, design, deployment and operation, including:

  • Design and technologies for current, evolutionary and innovative fast reactors (experimental, prototype or demonstration, and commercial size fast reactors) and subcritical hybrid systems, including non-sodium cooled fast reactors and sub-critical hybrid systems;
  • Economics, performance and safety of fast reactors and sub-critical hybrid systems;
  • Advanced fuel cycles and fuel options for the utilization and transmutation of actinides and long-lived fission products, including the utilization of thorium.

Many specific technologies are addressed in detail by other projects within the IAEA and in other international organizations. The TWG-FR keeps abreast of such work and cooperates and coordinates its activities with other IAEA projects, especially those of the Technical Working Group on Nuclear Fuel Cycle Options (TWG-NFCO), the International Project on Innovative Reactors and Fuel Cycle (INPRO), and the Department of Nuclear Safety and Security, in interfacing areas, as well as with related activities of other international organizations (e.g. OECD/NEA, GIF, EC/JRC, ISTC, JINR).


Full members:  

Belarus, China, France, Germany, India, Italy, Japan, Kazakhstan, Republic of Korea, Netherlands, Russian Federation, Slovakia, Sweden, Switzerland, United Kingdom, Ukraine, United States of America and two international organizations: OECD’s Nuclear Energy Agency (OECD/NEA) and the Joint Research Center of the European Commission (EC/JRC).


Argentina, Belgium, Czech Republic, Mexico, Romania, Spain and the Generation IV International Forum (GIF).


The TWG-FR meets at regular intervals but no more than once in a year with each meeting lasting up to five workings days. Extraordinary meetings may be called when required.

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