Russia expects to load the reactor core of the BN-800 fast neutron reactor at Beloyarsk-4 entirely with commercial mixed oxide uranium-plutonium (MOX) fuel in 2022, according to station director Ivan Sidorov.
In February 2021, a third of the reactor core was loaded with commercial MOX fuel in what Moscow said was a step closer to Russia’s goal of closing the fuel cycle. Operator Rosenergoatom said at the time that from then on only MOX fuel would be added to the BN-800 core.
MOX fuel contains more than one oxide of fissile material, usually plutonium oxide blended with natural uranium, reprocessed uranium or depleted uranium oxide. MOX fuel can also use weapons-grade plutonium from military sources.
The industrial production of MOX fuel in Russia is part of a federal programme to develop a new generation of nuclear technologies. The MOX fuel project was led by Tvel. Production began in late 2018.
The fuel pellets in the MOX assemblies were made of a mixture of depleted uranium oxides accumulated from enterprises connected to Tvel and plutonium oxides separated during the reprocessing of spent nuclear fuel.
Recycling fissile material in this way is known as closing the nuclear fuel cycle. The overall toxicity, fissile content and volume of the waste produced is reduced while the fissionable residuals are recycled for energy production.