Research reactor VVR-K at Kazakhstan’s Institute of Nuclear Physics of the National Nuclear Centre (INP NNC) has been upgraded and converted to use low enriched uranium (LEU) fuel. The first criticality of VVR-KN using new fuel enriched to 19.7% U-235 took place on 24 May. LEU fuel for VVR-K reactors was designed as a joint effort involving Russia’s NN Dollezhal Research & Development Institute of Power Engineering (NIKIET) and the Novosibirsk Chemical Concentrates Plant (NCCP), which is part of Russian state nuclear corporation Rosatom’s Fuel company Tvel. The project was undertaken within the framework of the Russia-US Reduced Enrichment for Research and Test Reactors (RERTR) programme under the auspices of the International Atomic Energy Agency.

The pool-type VVR-KN reactor was put into operation in 1967 using highly enriched uranium fuel. Design work on new LEU fuel began in 2003. In 2009 development of the fuel assembly was completed and preproduction and testing of the assemblies began the next year. The first batch of VVR-KN fuel, made by NCCP, was delivered to Kazakhstan in 2012. INP NNC director general Sayabek Sahiev said the new fuel will make it possible to double the neutron flux in the reactor. Russian company CNIIP-Systenatom designed a new control and protection system as part of the reactor upgrades.