U.S., Japan near end of HEU-to-LEU transition, plan expanded fusion partnership

During a state visit to the White House by Japanese prime minister Fumio Kishida on April 10, the Department of Energy announced that U.S. and Japanese agencies had cooperated to remove all high-enriched uranium (HEU) from the Japan Materials Testing Reactor Critical Assembly (JMTRC) of the Japan Atomic Energy Agency (JAEA) two years ahead of schedule.

One day earlier, U.S. deputy secretary of energy David M. Turk and Japan's minister of education, sports, science, and technology Masahito Moriyama met in Washington, D.C., to discuss the two nations' collaboration on fusion energy. On April 10, they released a joint statement announcing a strategic partnership to accelerate the demonstration and commercialization of fusion energy.

HEU removal: In December 2023, the Department of Energy's National Nuclear Security Administration worked with Japan's Ministry of Education, Culture, Sports, Science, and Technology (MEXT) and the JAEA to transport the remaining HEU from the JMTRC to the United States. The removal fulfills a commitment made by NNSA administrator Jill Hruby and MEXT former deputy minister Takashi Yanagi in November 2021, and according to the NNSA it was completed with financial support of the Defense Threat Reduction Agency.

The news underscores the two countries' continued commitment to minimize the use of HEU in civilian applications. Work is ongoing under an agreement reached in September 2022 to convert the Kindai University Teaching and Research Reactor-Japan's last remaining HEU-fueled research reactor-to high-assay low-enriched uranium (HALEU) and remove its remaining HEU to the United States for downblending into LEU.

Fusion past and present: The United States and Japan have a long history of collaboration in fusion, including exchange programs and joint research under the Coordinating Committee on Fusion Energy (CCFE), which was created in 1979 and is implemented under an agreement on cooperation in research and development in science and technology.

The new partnership will "leverage" the CCFE, according to the joint statement, and advance the U.S. Bold Decadal Vision for Commercial Fusion Energy and Strategy for International Partnerships in a New Era of Fusion Development, as well as Japan's Fusion Energy Innovation Strategy. The two nations will pursue complementary fusion resources and facilities, including in universities, national laboratories, and private companies.

Fusion pillars: The DOE and MEXT plan to develop their fusion partnership through the CCFE, which is cochaired by both agencies and is expected to meet in the coming months. The CCFE will "identify and delineate priority U.S.-Japan collaborative opportunities to realize our shared vision for fusion energy as an integral part of the world's future energy supply." The partners intend to include six "pillars" in their partnership:

• Address the scientific and technical challenges of delivering commercially viable fusion energy systems.
• Explore opportunities for shared access and/or development of facilities for fusion research and development, and investigate how a coordinated, strategic approach could maximize value for the United States and Japan.
• Promote the international harmonization of regulatory frameworks and codes and standards by leveraging the NRC's rulemaking efforts as well as ongoing discussions carried out through the International Atomic Energy Agency and the Agile Nations Fusion Energy Working Group.
• Identify and support the development of resilient global supply chains that facilitate commercial fusion deployment, and consider discussions among fusion industry groups in the respective countries.   
• Support public engagement to facilitate a social license for deploying fusion energy and to support an equitable clean-energy transition.
• Promote skills development to ensure a robust, inclusive, and diverse workforce for the fusion sector in the next decade and beyond.