The US Department of Energy (DOE) National Nuclear Security Administration (NNSA) said Japan and the US had removed all highly enriched uranium (HEU) from Japan Atomic Energy Agency (JAEA)’s Japan Materials Testing Reactor Critical Assembly (JMTRC) two years ahead of schedule.
The JMTRC at the Oarai R&D Centre was built in 1965 in advance of operation of the adjacent Japan Materials Testing Reactor (JMTR). It was used to perform various critical experiments to collect data on characteristics of the JMTR core and in-core irradiation facilities. The JMTR, now in permanent shutdown, began operation in 1968. The decommissioning plan of JMTR was approved in 2021 and it is now awaiting decommissioning.
The news of the HEU removal was welcomed by Japanese Prime Minister Fumio Kishida and US President Joe Biden during Kishida’s state visit to Washington. According to NNSA, the announcement also highlighted their continued commitment to minimise the use of HEU in civilian applications and noted progress since Biden’s state visit to Japan in May 2022.
In the two years since Biden and Kishida announced the removal of HEU from three Japanese sites, the two countries also have removed all HEU from the Kyoto University Critical Assembly and committed to convert the Kindai University Teaching & Research Reactor, Japan’s last remaining HEU-fuelled research reactor, to high-assay low-enriched uranium (HALEU) and remove its remaining HEU to the US.
In December 2023, NNSA, Japan’s Ministry of Education, Culture, Sports, Science & Technology (MEXT) and JAEA transported the remaining HEU from the JMTRC to the US. NNSA noted that this fulfils a commitment made by NNSA Administrator Jill Hruby and MEXT former Deputy Minister Yanagi Takashi in November 2021 and was completed more than two years ahead of schedule with financial support from the Defense Threat Reduction Agency (DTRA).
“This most recent removal highlights the shared commitment of the United States and Japan’s to minimise highly enriched uranium and the close partnership between our countries,” said Corey Hinderstein, Deputy Administrator for Defense Nuclear Non-proliferation. “The Defense Threat Reduction Agency helped our teams achieve this milestone years earlier than would have otherwise been possible.”
Most of JMTRC’s HEU was repatriated to the US between 2003 and 2009 following its decommissioning in 1996. The removal represents ongoing coordination between NNSA, MEXT, JAEA, and the Y-12 National Security Complex in Oak Ridge, Tennessee, which provided technical support for the project and received the HEU, which will be down-blended to low-enriched uranium.
NNSA’s Office of Material Management & Minimisation works with partner countries and international institutions to eliminate the need for, presence of, or production of weapons-usable nuclear material. To date, the office, jointly with domestic and international partners, has converted or verified as shut down 109 research reactors and medical isotope production facilities and removed or confirmed the disposition of over 7,340 kilograms of weapons-usable nuclear material.
In August 2022, NNSA said jointly with MEXT it had removed 45 kilograms of HEU from Japan’s Kyoto University Critical Assembly (KUCA) and returned it to the US, fulfilling a commitment made at the 2016 Nuclear Security Summit. The project was implemented over three years. This followed a May 2022 announcement that NNSA and MEXT had removed 30 kilograms of HEU from three Japanese research reactors in March 2022.
Image: The Japan Materials Testing Reactor
