During the plant’s first refueling outage, staff loaded 18 MOX assemblies into the reactor core – the first phase of a plan to replace all remaining uranium-based fuel at Beloyarsk-4 with MOX fuel by the end of 2021.
Tvel said another batch of 180 MOX assemblies is scheduled to be loaded into the BN-800 reactor core later this year.
In August 2019, Tvel delivered the first MOX fuel batch to Beloyarsk-4. The assemblies were manufactured by the Mining and Chemical Combine in Zheleznogorsk, Krasnoyarsk region.
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.
According to Tvel, the BN-800 reactor unit had already used a mix of experimental MOX assemblies and uranium fuel during its initial physical startup testing phase.
MOX fuel is nuclear fuel that 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.
State nuclear corporation Rosatom said the fuel pellets in the MOX assemblies were made of a mixture of depleted uranium oxides accumulated from enterprises connected to state nuclear fuel company 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.
Beloyarsk-4, near Yekaterinburg in central Russia, is an 820-MW fast neutron reactor unit of the BN-800 design. It began commercial operation in 2016.
There is another commercially operational reactor at the Beloyarsk station, the Beloyarsk-3 BN-600 fast reactor unit, a smaller version of the BN-800, and two permanently shut-down light-water cooled graphite moderated reactors.