The US Department of Energy’s National Nuclear Security Administration (DOE/NNSA) said on 22 September that the last remaining batch of unirradiated highly enriched uranium (HEU) in Kazakhstan has been eliminated.

This activity fulfilled an agreement worked out between the two countries at the 2019 International Atomic Energy Agency (IAEA) General Conference.

NNSA and the Kazakhstan Ministry of Energy worked together to remove 2.9kg of unirradiated HEU from the IGR research reactor in Kurchatov and transport it more than 200 miles to a secure facility for processing, and downblending to low enriched uranium (LEU).

“The world is a little bit safer now that this material has been downblended into a less dangerous form,” said Lisa E Gordon-Hagerty, NNSA administrator and under secretary for nuclear security of DOE.

After being removed from the IGR research reactor, the unirradiated HEU fuel was shipped by truck in 25 special transportation casks to the Ulba Metallurgical Plant in Ust-Kamenogorsk.

Once delivered, the downblending process involved crushing and grinding the graphite/uranium blocks, oxidising the graphite material, dry mixing with LEU powder, dissolving the uranium, and adjusting to get the uranium oxide to 19.8% enrichment. The entire process was conducted following International Atomic Energy Agency (IAEA) safeguards.

“The uranium can now be used as fuel for LEU research reactors, further supporting NNSA’s HEU minimisation efforts,” NNSA said.

Building on this cooperation, the USA and Kazakhstan signed a Joint Statement during the 2020 IAEA General Conference, committing to convert the IVG.1M research reactor at Kazakhstan’s National Nuclear Centre from the use of HEU to LEU fuel in 2021. The international team has already completed testing of the IVG.1M LEU fuel and the statement marks the transition to the final phase of conversion.

The USA and Kazakhstan have been collaborating on conversion of Kazakhstan's research reactors from HEU to LEU for more than a decade. Previous accomplishments include the elimination of all HEU from the VVR-K reactor, including the downblending of 49.3kg of unirradiated HEU and the removal of 158.3kg of irradiated HEU.