The successful transfer of the material was announced by the US Department of Energy’s National Nuclear Security Administration, in partnership with Japan’s Ministry of Education, Culture, Sports, Science and Technology and the Japan Atomic Energy Agency, and was completed in close partnership with the UK’s Nuclear Transport Solutions and Civil Nuclear Constabulary. It is the largest single international shipment of uranium in the history of the National Nuclear Security Administration and signifies a continuation of the long-standing nuclear security and nonproliferation cooperation between the two nations, it said.
HALEU – uranium enriched to contain between 5% and 20% uranium-235 – is crucial for next-generation nuclear fuels and will be used by many advanced reactors. The USA is working to build up its supply chain for the material: the Energy Act of 2020 directed the establishment of the to ensure access to HALEU for civilian domestic research, development, demonstration, and commercial use, and an Executive Order issued by President Donald Trump in April 2025 mandates the Department of Energy to ensure a long-term supply of the material and to reduce reliance on foreign sources of fuel. The material from Japan will – once processed – help bridge the gap between supply and demand under the programme, the NNSA said.
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Matthew Napoli and Japanese Ambassador Shigeo Yamada celebrate the transfer (Image National Nuclear Security Administration)
The HALEU that has been shipped to the USA had originally been intended to fuel the Japan Atomic Energy Agency’s Fast Critical Assembly – a facility which had operated since 1967 to study the neutronic characteristics of fast reactors. In March 2014, then-Japanese prime minister Shinzo Abe and US president Barack Obama pledged to remove and dispose of all the highly-enriched uranium research reactor fuel from the reactor under the auspices of the Global Threat Reduction Initiative set up by the USA in 2004, with the Fast Critical Assembly itself being converted to use low-enriched uranium and reassigned to transmutation and disposition of wastes.
The material will be reconstituted into a form usable for US industry at the National Nuclear Security Administration’s Y-12 National Security Complex in Oak Ridge, Tennessee.
“This milestone accelerates our progress towards a secure and independent energy future, while reaffirming our commitment to nuclear nonproliferation,” said Matthew Napoli, National Nuclear Security Administration’s Deputy Administrator for Defense Nuclear Nonproliferation. “Through this partnership with Japan, we are fuelling the next generation of nuclear power, and solidifying America’s energy dominance.”
