NNSA Administrator Jill Hruby in the KUCA reactor room with Professor Hironobu Unesaki, left, and Ken Nakajima, Director of the Institute for Integrated Radiation and Nuclear Science at Kyoto University. Courtesy/NNSA
Kyoto University and Y-12 National Security Complex technical experts prepare the highly enriched uranium shipping containers for transportation. Courtesy/Kyoto University
WASHINGTON, D.C. — Fulfilling a commitment made at the 2016 Nuclear Security Summit, the U.S. Department of Energy’s National Nuclear Security Administration (NNSA) and Japan’s Ministry of Education, Culture, Sports, Science and Technology (MEXT) have announced the removal of all highly enriched uranium (HEU) from the Kyoto University Critical Assembly (KUCA).
Over three years, NNSA, MEXT, and Kyoto University transferred 45 kilograms of HEU from Japan to the United States as part of their shared nonproliferation goal of minimizing HEU worldwide. This accomplishment follows the May announcement by President Biden and Prime Minister Kishida that NNSA and MEXT had removed 30 kilograms of HEU from three Japanese research reactors in March 2022.
The removal effort was primarily undertaken during the COVID-19 pandemic and required close collaboration to overcome numerous challenges – both technical and logistical. Notably, to accomplish critical work that could only be performed in person, U.S. technical experts underwent a 14-day quarantine upon their arrival in Japan on four separate occasions.
Following shipment to the United States, the HEU was securely transported to the Y-12 National Security Complex in Oak Ridge, Tenn., and the Savannah River Site in Aiken, S.C., where it will be downblended to low-enriched uranium (LEU) and/or dispositioned.
NNSA Administrator Jill Hruby and Senior Deputy MEXT Minister Takashi Yanagi marked this milestone in Tokyo.
“Completing this removal campaign was a monumental effort that demonstrates the close nuclear security relationship the United States and Japan enjoy,” Administrator Hruby said. “Minimizing the use of HEU in civilian applications allows facilities like KUCA to continue their essential training and research missions without risk that the fuel could be used to produce an improvised nuclear device. I want to thank the team for seeing the job through despite pandemic restrictions.”
DOE/NNSA, MEXT, and Kyoto University are continuing to pursue their goal of converting the KUCA to use LEU fuel by the end of 2023, allowing it to carry out its mission of nuclear research and training for Japanese students for years to come. This collaboration reached a major milestone with the April 2022 approval of the facility safety analysis report by Japan’s Nuclear Regulation Authority. This is the first approval of its kind since the Fukushima incident in 2011 and as such faced an unprecedented level of scrutiny.
DOE/NNSA’s Office of Material Management and Minimization works with partner countries and international institutions around the world to eliminate the need for, presence of, or production of weapons-usable nuclear material. To date, the office has worked jointly with domestic and international partners and successfully converted or verified as shutdown 108 research reactors and medical isotope production facilities and removed or confirmed the disposition of nearly 7,275 kilograms of weapons-usable nuclear material – enough for approximately 325 nuclear weapons.