Japan to upgrade test facility for fast reactor research

The Yomiuri Shimbun

17:37 JST, January 10, 2022

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.

A budget of ¥900 million has been earmarked to improve AtheNa, a facility of the Japan Atomic Energy Agency, of which ¥600 million has been spent. Work is already underway.

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.

JAEA will sign this month a memorandum of understanding with U.S. nuclear start-up TerraPower, LLC over the technological cooperation. The fast reactor to be jointly developed would generate power by extracting heat from the core with liquid sodium.

AtheNa has no nuclear reactor of its own. It is one of the world’s largest test facilities to obtain such data as the change in temperature, and the way the sodium flows, by circulating high-temperature sodium in about 200 meters of piping.

By connecting the piping with devices of the same types as those to be used in a fast reactor, AtheNa can also conduct experiments to confirm durability and change in performance under varied temperature conditions. Yet to be developed, however, is a heating system to raise the temperature of sodium to over 500 C, close to the conditions when a nuclear reactor is in operation.

Therefore, the government has injected ¥600 million to begin work to install a heating system and modify the relevant piping and other components. In the budget for fiscal 2022, it has included an additional ¥300 million for related expenses. The government will improve the functions of AtheNa so it can be utilized from fiscal 2023 onward for the joint development of the next-generation fast reactor with the United States.

According to JAEA, there is no facility similar to AtheNa in the United States. Senior officials of TerraPower have conducted an on-site inspection and reportedly shown high interest in the technological development at AtheNa.

Joyo is a nuclear reactor that uses sodium as a coolant, as the next-generation fast reactor will. With Joyo, researchers can analyze what sort of impact high-speed neutrons will have on such elements as fuels and structures inside the reactor. Joyo is currently suspended due to safety screenings by the Nuclear Regulation Authority.

To accelerate the restart of Joyo, the government will hasten the preparations for work on safety measures that will be needed after it passes the screening, including reinforcing Joyo’s quake resistance. Of the total cost of about ¥14 billion, it has secured ¥4 billion in fiscal 2021, to restart Joyo from fiscal 2024 or later.