Irradiated fuel will be transferred to Dimitrovgrad for examination
Russia has completed a pilot operation programme for its Remix uranium-plutonium nuclear fuel at Unit 1 of the Balakovo nuclear power station in the south of the country, a statement by Russian state nuclear corporation Rosatom said.
The statement said six lead test assemblies were loaded into the VVER-1000 pressurised water reactor unit in 2021 and have now completed three standard 18-month fuel cycles.
The final three assemblies were removed during a recent refuelling outage, concluding the test programme.
Rosatom said the fuel has demonstrated stable performance, with no deviations from design parametres observed during operation. The irradiated fuel will be transferred to the Dimitrovgrad reactor research institute for post-irradiation examination, which is expected to support qualification of the fuel for future use.
The Remix fuel is produced from a mixture of regenerated uranium and plutonium extracted from reprocessed spent fuel, combined with enriched uranium. The fuel contains up to 1.5% plutonium and has a neutron spectrum similar to standard uranium fuel.
Rosatom said the approach is intended to enable partial closure of the nuclear fuel cycle in light water reactors by allowing reuse of nuclear materials.
The test programme is a prerequisite for the commercialisation and wider introduction of VVER uranium-plutonium fuel, Rosatom has said earlier.
Alexander Ugryumov, senior vice president at Rosatom’s fuel division Tvel, said the next step will be the operation of assemblies containing depleted uranium and up to 5% plutonium.
Rosatom said Remix fuel will be able to be introduced into existing reactors without design modifications or additional safety measures.
As part of the programme, in early 2021, three fuel assemblies, each containing six experimental Remix fuel rods, completed pilot operation that started in 2016 at Unit 3 at Balakovo.
Traditionally, it is MOX (mixed-oxide) fuels that contain both plutonium from spent fuel and uranium. But usually, the plutonium content averages about 10% for use in pressurised and boiling water reactor and up to 30% for use in fast neutron reactors.
Closing the nuclear fuel cycle means irradiated fuel can be reused instead of stored, reducing environmental risks and the volume of radioactive waste requiring disposal.
