Rosatom has announced that the BN-800 sodium-cooled fast neutron reactor at unit 4 of the Beloyarsk NPP in the Sverdlovsk district of Russia will operate using only mixed-oxide (mox) fuel by 2019. The plant currently uses a "hybrid" consisting of fuel based on uranium oxide and MOX fuel in two versions – tablet and vibro-packed. The share of mox fuel is about 20%. The unit was connected to the grid last December and will begin commercial operation by the end of this year. Mox fuel assemblies were tested earlier at Beloyarsk unit 3 which has a smaller BN-600 fast reactor. "About 100 of such assemblies in small batches have been tested in this reactor during a number of years," the plant said.

Meanwhile, A decision on whether to go ahead with the construction of a larger BN-1200 fast neutron reactor at Beloyarsk has not yet been taken and will depend on the results of operating Beloyarsk 4, Russian officials said. Nuclear utility Rosenergoatom had planned to build two BN-1200 units at Beloyarsk with commercial operation scheduled by 2025. The Russian government said in November 2013 that if the BN-1200 design was successful, two reactors of this type will be built at a new South Urals NPP in Ozersk, about 200 km southeast of Yekaterinburg.