Fuel assemblies (FA) of PWR-1000, containing experimental fuel elements with REMIX fuel, were operated in the reactor of power unit No. 3 of the Balakovo NPP for three fuel campaigns - about 5 calendar years. The unloading from the reactor took place as part of the scheduled preventive maintenance of the power unit, which is being performed at the nuclear power plant these days.

REMIX fuel is designed to reduce the consumption of natural uranium in the nuclear power industry and to reuse the components of already irradiated fuel. The main advantage of a closed nuclear fuel cycle is the possibility of using plutonium formed during irradiation of uranium-238.

“The pilot industrial operation of the innovative fuel at the Balakovo NPP was successful,” said Yury Ryzhkov, deputy chief engineer for Safety and Reliability. In total, three fuel assemblies were loaded into the reactor of power unit No. 3 along with standard fuel assemblies, each of which, along with standard fuel elements, contained six fuel elements with REMIX fuel. During all five years of testing, our specialists monitored the neutronic and life characteristics of experimental fuel assemblies - there were no deviations from normal operation, which confirms the design properties of the new nuclear fuel."

After unloading from the reactor, the fuel assemblies with innovative fuel were moved to the spent fuel pool to remove activity and residual heat from the fuel to allowable values for its transportation.

In 2023, they will be sent to the Research Institute of Atomic Reactors (Dimitrovgrad) for post-reactor research.

In 2021, Rosatom established a pilot production of full-scale fuel assemblies with REMIX fuel in cooperation between FSUE Mining and Chemical Combine, where REMIX tablets are manufactured, and the Siberian Chemical Combine (JSC SCC, an enterprise of the Fuel Company of Rosatom TFE), at the site of which fuel elements are manufactured and REMIX-FA are assembled.

“Experimental fuel assemblies with REMIX fuel at the Siberian Chemical Combine are manufactured in the FA-2M design - this very design is used in the PWR-1000 reactors at the Balakovo NPP. We expect that the next step in the implementation of the program for the development and commercialization of Russian uranium-plutonium fuel for PWR should be the pilot operation of several fuel assemblies with all fuel elements with REMIX fuel, ” noted the Vice President for Science and Technology TFE Alexander Ugryumov.

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REMIX fuel (REMIX - regenerated mixture) is an innovative Russian development for light-water thermal reactors, which form the basis of modern nuclear power. Its fuel composition is made from a mixture of reprocessed uranium and plutonium, which is formed during the reprocessing of spent nuclear fuel, with the addition of enriched uranium. Unlike uranium-plutonium fuel for "fast" reactors (MNUP and MOX), REMIX fuel is characterized by a lower plutonium content (up to 5%). Its neutron spectrum does not differ from standard enriched uranium fuel, so the behavior of the fuel in the reactor core and the amount of plutonium generated from uranium as a result of irradiation are generally identical.

For the NPP operators, this means that in the future, REMIX fuel can be introduced without changes in the reactor design and additional safety measures. The use of such fuel will make it possible to expand the resource base of the nuclear power industry many times over by closing the nuclear fuel cycle, as well as to reuse the irradiated fuel instead of storing it.

The strategic objective of the prospective introduction of REMIX fuel is to close the nuclear fuel cycle using thermal reactors.