A new generation of nuclear fuel assemblies, designated TVS-5, has been loaded into the VVER-1200 reactor core at Unit 6 of the Novovoronezh Nuclear Power Plant, marking a significant step in Russia's transition toward a closed nuclear fuel cycle.

Developed as part of Rosatom’s strategy for a dual-component nuclear power system, the TVS-5 assemblies contain uranium-plutonium fuel and will undergo pilot operation over three 18-month fuel cycles alongside conventional enriched uranium dioxide fuel.

Manufactured by the Novosibirsk Chemical Concentrates Plant, a subsidiary of Rosatom’s Fuel Division, the new assemblies are designed for fully automated fabrication—an essential requirement for scaling up industrial production of uranium-plutonium fuel for VVER-type thermal neutron reactors.

Alexander Ugryumov, Senior Vice President for Research and Development at TVEL, Rosatom’s fuel division, emphasized the importance of this milestone.

“Introducing regenerated nuclear material into classical thermal reactors is key to closing the fuel cycle. To achieve this at scale, automation in fuel fabrication—similar to that for fast reactors—is critical. The launch of TVS-5 at Novovoronezh is a vital step in validating this approach,” he said.

Russia’s long-term nuclear strategy centers on a dual-component system integrating both thermal and fast neutron reactors, underpinned by a closed fuel cycle.

The approach aims to enable the recycling of spent nuclear fuel into fresh uranium-plutonium fuel, ultimately balancing fuel use between thermal and fast reactors as deployment scales up.

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