Each of the batch of six fuel assemblies consists of Remix fuel rods with uranium-plutonium pellets instead of the traditional enriched uranium dioxide. Each VVER-1000 assembly contains 312 fuel rods.
The fuel pellets were manufactured at the Mining and Chemical Combine, a facility belonging to state nuclear corporation Rosatom in Zheleznogorsk.
The Remix assemblies will undergo a full operation cycle in one of the Russia’s VVER-1000 reactors.
Since 2016, three fuel assemblies, each containing six experimental Remix fuel rods, have been undergoing pilot operation at Unit 3 of the Balakovo nuclear power station. The third 18-month cycle of their irradiation began in 2020 and was completed this year.
Since 2016, Remix fuel assemblies have been in test use at the Balakovo-3 VVER-1000 nuclear power unit, about 900km southeast of Moscow, where a testing programme was completed in 2021.
Tvel said that unlike uranium-plutonium fuel for fast reactors, Remix fuel has a lower plutonium content, up to 1.5%, but its neutron spectrum does not differ from standard enriched uranium fuel, which makes it usable in existing reactors without changes to their design or additional safety measures.
