WASHINGTON — In 2016, Japan and the U.S. made a commitment to reduce the amount of highly enriched uranium in many Japanese facilities. It can be produced for research reactors or to be used in submarines.
This kind of uranium can also be used in nuclear weapons, and the agreement to get rid of it was part of a worldwide effort to prevent more devastating weapons from being made.
Over the course of 3 years, Japan sent around 45 kilograms of highly enriched uranium to the U.S. That includes 30 kilograms of highly enriched uranium that was removed from three Japanese research reactors in March 2022. In the U.S., it was downblended at facilities like Y-12.
Downblending is a process to make uranium less dangerous and incapable of producing the enormous blasts needed for nuclear weapons. It results in low-enriched uranium, which is then used in places like power plants.
The National Nuclear Security Administration works to remove weapons-grade uranium from civilian facilities across the world. Most recently, they announced that highly enriched uranium was removed from the Kyoto University Critical Assembly, used for studying reactor physics.
“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," said NNSA Administrator Jill Hruby. "I want to thank the team for seeing the job through despite pandemic restrictions.”
Crews had to navigate complex COVID-19 restrictions while also transporting highly enriched uranium from Japan to the U.S. Technical experts going to Japan had to be quarantined for 14 days when they arrived in the country, four separate times.
So far, the NNSA's Office of Material Management and Minimization has converted or shut down 108 research reactors and reported that around 7,275 kilograms of weapons-grade nuclear material had been dispositioned so far — enough for 325 nuclear weapons.