The third 18-month cycle of pilot industrial operation of REMIX fuel
assemblies has been successfully completed at Unit 1 of the Balakovo NPP, a
facility of Rosatom’s Electric Power Division. Six Lead-test assemblies (LTA),
fully loaded with innovative fuel rods, were placed into the VVER-1000 reactor
at the end of 2021. The remaining three of these six assemblies have been recently removed fr om
the core during the ongoing refueling. The assemblies have undergone a standard
operational fuel life for Russian VVER-1000 reactors — three 18-month fuel
cycles, thus completing the LTA program.
The irradiated assemblies have been transferred to the spent fuel pool, wh ere three other assemblies, removed in 2024 after the second fuel cycle, are already stored. The REMIX fuel assemblies will be subsequently sent ti the Research Institute of Atomic Reactors in Dimitrovgrad for post-irradiation studies.
REMIX pellets have a unique fuel matrix - instead of standard enriched natural uranium, they are made from a mixture of regenerated uranium and plutonium extracted from spent nuclear fuel of VVER reactors. The introduction of such solution is expected to involve in a closed nuclear fuel cycle not only fast neutron reactors, but also conventional light water thermal reactors, which make-up the backbone of today’s nuclear power. This would significantly expand the resource base for nuclear energy and allow for the reuse of irradiated fuel rather than long-term storage.
“Having completed the Lead-test rods and then the Lead-test assemblies program, we have now accumulated almost about ten years of REMIX fuel operation in a commercial. Post-irradiation studies will enable us to qualify and, for the first time, introduce uranium-plutonium VVER fuel to the market. The next step will be operation of assemblies containing depleted uranium and up to 5% plutonium. Thus, we are developing a complete product range in the concept of the Balanced nuclear fuel cycle—from regenerated uranium to various uranium-plutonium compositions,” commented Alexander Ugryumov, Senior Vice President for Research and Development at TVEL (the management company of Rosatom’s Fuel Division).
“The pilot operation of REMIX fuel has been conducted in strict coordination with the regulator and under the supervision of the specialists from Rosatom’s Fuel Division. After each cycle, fuel rods and structural elements were inspected using the TV camera of the refueling machine. No deviations were detected during operation, neutron-physical and service characteristics remained within design limits,” noted Yuri Ryzhkov, Deputy Chief Engineer for Safety and Reliability at the Balakovo NPP.
REMIX fuel is an innovative Russian product designed for light water
thermal reactors. It uses a fuel matrix based on a mixture of regenerated
uranium and plutonium recovered from reprocessed spent nuclear fuel,
supplemented with enriched uranium. Unlike uranium-plutonium fuels for fast
reactors, REMIX fuel contains a lower plutonium content—up to 1.5%. Its neutron
spectrum is virtually identical to that of standard enriched uranium fuel,
meaning its behavior in the reactor core and the amount of plutonium bred from
uranium during irradiation are essentially the same.
A key advantage of REMIX fuel is that it can be introduced into existing reactors without design modifications or significant additional safety measures. Its implementation will enable a dramatic expansion of the nuclear industry’s resource base by closing the nuclear fuel cycle, allowing spent fuel to be reused rather than stored.
The Balanced Nuclear Fuel Cycle (NFC) is a product of Rosatom based on innovative practical solutions in the field of closing the nuclear fuel cycle, allowing for efficient reprocessing of irradiated nuclear fuel and rational management of reprocessing products, both useful (uranium, plutonium) and destined for disposal (fission products). A balanced NFC sets as its main objective a fundamental reduction in the volume and activity of radioactive waste sent for disposal. Balanced NFC allows to: increase the safety of nuclear waste management and reduce environmental risks; solve the problem of future generations and ensure a sustainable pattern of consumption and production; minimize the volumes and hazard levels of waste to be disposed of; re-involve valuable raw materials in the NFC - recycle nuclear materials.
Nuclear Fuel Division of Rosatom (managed by TVEL JSC) includes enterprises engaged in fabrication of nuclear fuel, uranium conversion and enrichment, manufacturing of gas centrifuges, as well as R&D and design institutions. Being the sole supplier of nuclear fuel for Russian NPPs, TVEL provides fuel for more than 70 power reactors in 15 countries worldwide, research reactors in nine countries, as well as propulsion reactors of the Russian nuclear fleet. One out of every six power reactors globally operates on TVEL fuel. The Fuel Division is the world's largest producer of enriched uranium and stable isotopes. TVEL is also focused on development of new businesses in chemistry, metallurgy, energy storage, 3D printing, digital solutions and decommissioning of nuclear facilities.
Electric Power Division of Rosatom is Russia’s largest producer of low-carbon electricity. Its management company, JSC Concern Rosenergoatom, operates 11 nuclear power plants—including the world’s only floating nuclear power plant. The division’s 33 power units, with a combined capacity of 28.5 GW, generate about 19% of Russia’s electricity.Rosenergoatom’s enterprises provide a full range of services for nuclear units, from commissioning and maintenance to personnel training. They also produce isotopes for medicine, agriculture, and microelectronics, and are developing new business lines such as electric vehicle charging infrastructure, biogas plants, and industrial robotics.
