Natrium, a 345-MWe sodium fast reactor with a molten salt energy storage system, was developed by TerraPower and GE Hitachi Nuclear Energy. TerraPower is planning to build the first Natrium demonstration reactor by 2028 with 50-50 cost-shared funding of about $2 billion from the Department of Energy’s Advanced Reactor Demonstration Program. And for the requisite data and testing of reactor components to support that deployment, TerraPower is looking to Japan—a country with decades of experience developing sodium fast reactor designs and testing infrastructure.
TerraPower has signed a memorandum of understanding with the Japan Atomic Energy Agency (JAEA), Mitsubishi Heavy Industries (MHI), and Mitsubishi FBR Systems to share data and resources on the testing of sodium fast reactor components in an agreement that the parties anticipate will support the deployment of advanced reactors in both countries.
“As a nuclear innovation company, we value mutual learning with the broader global nuclear community and applying this expertise to ongoing efforts,” said Chris Levesque, president and chief executive officer of TerraPower, in a press release issued on January 31. “We appreciate the expertise that JAEA will bring to our project, and we are confident that our program will help them as they consider advanced reactors in Japan.”
Japanese capabilities: “This cooperation with TerraPower will contribute to further development of U.S.-Japan cooperation on sodium-cooled fast reactors,” said Toshio Kodama, president of JAEA. “We believe that it can provide a good opportunity for Japan to advance our SFR technologies toward carbon neutrality.”
Japan has experience developing sodium fast reactors dating back to the mid-1980s. Levesque noted that there are several differences between the Natrium reactor and previous sodium fast reactors in Japan. The Natrium reactor is a commercial power source that will utilize once-through high-assay low-enriched uranium fuel and is not intended for either breeding fissile material or for pairing with a reprocessing program.
Talking it through: In November 2021, the Washington Office of the Japan Atomic Energy Agency organized the Symposium of U.S.-Japan Nuclear Energy Research Cooperation, with participation from the DOE, the Nuclear Regulatory Commission, national laboratories, and U.S. companies, including TerraPower.
Levesque, speaking at the symposium, mentioned that JAEA and TerraPower were “considering cooperation” and described his tour of JAEA’s Oarai Research and Development Institute in January 2020, according to a report prepared by the JAEA. The Oarai site houses the Joyo test reactor and other facilities, including AtheNa, a large-scale sodium test facility for component development and demonstration.
During the symposium, Izuru Kobayashi, deputy commissioner for international affairs at Japan’s Agency for Natural Resources and Energy, explained that “following the conclusion of the memorandum of understanding for cooperation on [the Versatile Test Reactor], discussion on the cooperation in the Natrium reactor project with TerraPower is under way.”
The Versatile Test Reactor, a sodium-cooled fast reactor planned to test materials and components for multiple reactor types, is based on GE Hitachi’s PRISM reactor design. The DOE has identified Idaho National Laboratory as the preferred location for the VTR, but no funding was allocated to the project for fiscal year 2022.
Japanese research reinvestment: In early January, an article in the Japan News stated, “The government will significantly improve the functions of the AtheNa sodium experimental facility for fast reactor research in Ibaraki Prefecture, in connection with a next-generation fast reactor development project to be conducted jointly with the United States. . . . Work on safety measures will also be carried out swiftly at the Joyo experimental fast reactor, in order to restart the currently suspended facility. The government will use these two facilities as the common base for its joint fast reactor research with the United States.” A reported budget of ¥900 million (about $7.8 million) has been earmarked to improve AtheNa.
MHI sees possibilities: A January 27 post on the Japanese language website of Mitsubishi Heavy Industries Group indicates that the agreement with TerraPower was signed on January 26. According to MHI, the partners will use knowledge held by Hitachi-GE Nuclear Energy, Toshiba Energy Systems, Fuji Electric, and others involved in the construction of Joyo and Monju.
“With this memorandum, it will be possible to collaborate with domestic industries under JAEA,” MHI said. “In the future, through cooperation with TerraPower, we would like to develop cooperation in the development of fast reactors between Japan and the United States and to maintain and improve our technological capabilities related to the development of fast reactors.”
According to MHI, its work with TerraPower will focus on equipment design and manufacturing technology unique to sodium-cooled reactors, including refueling machines and damaged fuel detection systems.