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Technical Working Groups on Advanced Technologies for Light Water Reactors and Heavy Water Reactors (TWG-LWR and TWG-HWR)

The Technical Working Groups on Advanced Technologies in Light Water Reactors (TWG-LWR) and Heavy Water Reactors (TWG-HWR) are groups of international experts who provide advice and support IAEA programme implementation in the area of advanced technologies for water cooled reactors (WCRs) utilized for the production of electricity and/or heat.

The IAEA has been serving interested Member States as a focal point for information exchange and collaborative research and technology development for WCRs. The TWG-LWR was established in 1987, with the TWG-HWR following in 1997.  Both Working Groups address advances in national programmes, systems analyses and fuel utilization, including research and development, design, performance and cost related aspects of the reactor core, plant systems and components, and reactor and plant structures and containment.

More than 90% of the world's current nuclear power plants are LWRs and HWRs that will continue to play a major role in producing electricity and for non-electric applications. The continued and increasing demand for safe, clean, reliable and cost-effective electricity generation is a strong driver for technology holders to extend the operating life of nuclear power plants. The life of a nuclear power plant can be extended for several decades through refurbishment -modernizing and enhancing major equipment and systems to support long tenn operation. Over the next ten years, many Canada deuterium-uranium (CANDU) reactor refurbishment projects are planned and lessons from past refurbishments need to be shared for the benefit of all stakeholders. The work of TWG-HWR is extremely important in facilitating the development of the advanced technologies needed for safe, reliable, clean, and economic use of nuclear power. TWG-HWR provides a global forum for exchanging information on national nuclear power programmes, provide advice to the IAEA on its activities in technology development for HWRs, marshal support in the home countries for conduct of the agreed activities, and are a means for the IAEA to provide balanced <;l,nd objective information to all Member States on water cooled reactor technology status and advancements in a post-Fukushima world for near- and longer-term deployment. Members of TWG-HWR represent a global network of excellence and expertise in advanced technologies for HWRs providing the objective and professional advices throughout the year as well as during yearly TWG's meetings, so that the Agency might consider including meaningful new programmes and activities in their biennium planning of programmatic activities (coordinated research projects, technical meetings, training courses, development of new learning tools, databases and online platforms to preserve and share knowledge) in the field of advanced HWR technologies. Since the interest in Member States in advancements, refurbishment and deployment of HWRs is still there and growing, therefore, the continuation of TWG-HWR, is vital to provide continued support to Member States related to the scope of TWG.

Scope and Functions

The following technical areas are within the Scope of the TWG- Heavy Water Reactors:

  • Design and technologies for current and advanced Heavy Water Reactors;
  • Economics, performance and engineering systems safety for current and advanced Heavy Water Reactors;
  • Impact of the advanced fuel cycles and fuel options on reactor design for current and advanced Heavy Water Reactors;
  • Infrastructure specific to the development and deployment of Heavy Water Reactors;
  • Advances in national programmes;
  • Plant operation and maintenance;
  • Research, development, design, performance and cost related aspects of reactor core, plant systems and components, reactor and plant structures and containment.


The functions of the TWG are the following:

  • To provide advice to DDG-NE on specific topics of relevance to the IAEA's programmatic activities;
  • To share information and knowledge on national and international programmes;
  • To contribute to the development and/or review of selected IAEA publications, in particular from the IAEA Nuclear Energy Series, assess existing gaps and advise on the preparation of new publications ore-learning materials;
  • Upon request, to present to the Standing Advisory Group on Nuclear Energy (SAGNE) the key findings of the TWG meeting; and
  • To share experience and advice on increasing the participation of young professionals and improving the gender balance in the nuclear sector.


The members of the Technical Working Group are appointed by the IAEA Deputy Director General, Head of the Department of Nuclear Energy, following consultation with the respective national authorities or organizations.

Term Duration

4 years, 2021-2024

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