Russia's Smolensk NPP begins loading improved nuclear fuel

On September 1, 2026, local time, Unit 1 of Russia's Smolensk Nuclear Power Plant began gradually loading improved nuclear fuel. The fuel assemblies feature adjusted uranium-235 enrichment and erbium oxide content, as part of the RBMK-1000 reactor modernization program aimed at enhancing unit operational safety and efficiency.

The Smolensk NPP is part of the electric power division of Rosatom and is operated by Rosenergoatom. The fuel assemblies loaded into the core this time use lower uranium-235 enrichment and lower erbium oxide content. According to relevant calculations, the new fuel can compensate for changes in core neutronics parameters following graphite stack repair, creating more favorable conditions for subsequent unit operation while maintaining reactor controllability and inherent self-protection capability.

Anatoly Karpinsky, Deputy Chief Engineer of the Smolensk NPP, stated that since the mid-2000s, the uranium-erbium fuel used at the plant has had a uranium-235 enrichment of 2.8% and an erbium oxide mass fraction of 0.6% as a burnable neutron absorber. As the units undergo graphite stack lifetime management to improve safety and extend operational life, the fuel composition also requires corresponding adjustments. Based on computational studies conducted separately by NIKIET (Dollezhal Research and Development Institute of Power Engineering), the Kurchatov National Research Center, and VNIIAES (All-Russian Research Institute for Nuclear Power Plant Operation), the final new fuel parameters were determined as uranium-235 enrichment of 2.7% and erbium oxide content of 0.35%.

Prior to fuel assembly loading, the plant analyzed various reactor operating modes, completed nuclear and radiation safety justifications for the use of the new fuel, and certified the relevant new software. During the certification process, specialists from the nuclear safety and reliability department and the thermal engineering automation and instrumentation workshop participated in bench tests. Amendments to the Unit 1 operating license conditions have also been approved.

The Smolensk NPP stated that data from the initial 200 fuel assemblies put into operation will be used for subsequent analysis to substantiate the feasibility of fully adopting this type of fuel assembly across all units at the plant, and to provide a basis for extending unit operational life to 50 years.

The Smolensk NPP is located approximately 150 km west of the city of Smolensk and currently operates three RBMK-1000 units, each with a capacity of 1,000 MW. The plant supplies more than 20 billion kWh of electricity annually to the Unified Power System of Russia.