Russia begins trial operation of new nuclear fuel for VVER units

The first unit of Russia’s Balakovo nuclear power plant has begun operating with a new type of fuel for VVER reactors. Some of the fuel assemblies contain MOX fuel, and the fuel rods also have an additional chromium coating. Besides its safety function, this coating makes it possible to automate nuclear fuel production. The use of hybrid fuel made from secondary products will reduce natural uranium consumption over the nuclear power plant’s entire lifetime. 

Russian nuclear fuel producer TVEL announced that its parent company Rosatom has begun testing new fuel for pressurized water reactor units of the VVER type. At Unit 1 of the Balakovo nuclear power plant (VVER-1000) with an installed capacity of 1000 MW, technicians loaded fuel assemblies containing accident-tolerant MOX nuclear fuel into the reactor.

“The selected combination of fuel and structural materials is key to achieving the strategic goal of integrating not only innovative fast reactors but also conventional light-water thermal reactors into a closed fuel cycle. MOX technology enables secondary nuclear materials—depleted uranium and plutonium extracted from spent nuclear fuel—to be used to produce fresh fuel,” TVEL said in a press release.

The new fuel batch comprises three fuel assemblies, each made up of 312 fuel rods. These have a chromium coating over the conventional zirconium-tin alloy cladding. 18 rods contain MOX fuel made from a mixture of plutonium oxides and depleted uranium.

“Chromium-coated fuel rod cladding, originally developed for accident-tolerant fuel, not only enhances safety and resilience in severe accident scenarios, but also enables fully automated, ‘lights-out’ fuel production, eliminating manual intervention and minimizing radiation exposure for personnel,” TVEL added, outlining the benefits of the new fuel.

20% lower uranium consumption

Rosatom has been testing REMIX fuel at Balakovo Unit 1 since 2021. It also uses fuel assemblies made from a mixture of uranium and plutonium oxides. However, compared with REMIX fuel, MOX contains several times more plutonium and uses depleted uranium instead of enriched uranium. According to calculations by Rosatom experts, a combination of MOX fuel (25%) and REMIX fuel (75%) contains the same amount of plutonium, meaning VVER reactors could begin using it without further modifications. The estimated saving in natural uranium over the power plant’s entire life cycle is 20%.

“Rosatom’s strategic goal and our vision for the future is a two-component nuclear power system in which fast and thermal reactors operate in a closed fuel cycle, with spent fuel from some units becoming feedstock for fresh fuel in other reactors. Everything we do in our research and development projects on VVER fuel is primarily aimed at achieving this goal,” said Alexander Ugryumov, senior vice president for research and development at TVEL.