The first full refuelling of Russia’s BN-800 fast reactor at unit 4 of the Beloyarsk NPP with only uranium-plutonium mixed oxide (mox) fuel was completed during the recent scheduled maintenance outage, fuel company TVEL (part of Rosatom) announced on 24 February. The unit, which was shut down on 8 January, has been reconnected to the grid and has resumed electricity production. The first 18 serial mox fuel assemblies were loaded into the reactor in January 2020, and another 160 fuel assemblies have now been added to them. Thus, the BN-800 core is now one-third filled with innovative fuel and in future only mox fuel will be loaded into the reactor.
“Beloyarsk NPP is now one step closer to implementation of the strategic direction for the development of the nuclear industry - the creation of a new technological platform based on a closed nuclear fuel cycle,” said Ivan Sidorov, Director of the Beloyarsk NPP. “The use of mox fuel will make it possible to involve in fuel manufacture the isotope of uranium that is not currently used. This will increase the fuel base of the nuclear power industry tenfold. In addition, the BN-800 reactor can reuse used nuclear fuel from other NPPs and minimise radioactive waste by “afterburning” long-lived isotopes from them. Taking into account the planned schedule, we will be able to switch to a core with a full load of mox fuel in 2022.”
The fuel assemblies were manufactured at the Mining and Chemical Combine (MCC, Zheleznogorsk, Krasnoyarsk Territory). Unlike enriched uranium, which is traditional for nuclear power, the raw materials for the production of mox fuel pellets are plutonium oxide produced in power reactors and depleted uranium oxide (obtained by defluorination of depleted uranium hexafluoride - DUHF, the secondary "tailings" of the enrichment plant.
“In parallel with loading the BN-800 core with mox fuel, Rosatom specialists are continuing to develop technologies for the production of such fuel at the MCC,” said Alexander Ugryumov, vice president for research, development and quality at TVEL. “In particular, the production of fresh fuel using high-background plutonium extracted from the irradiated fuel of VVER reactors has been mastered: all technological operations are fully automated and are performed without the presence of personnel in the immediate vicinity. The first 20 mox-FAs incorporating high-background plutonium have already been manufactured and passed acceptance tests, and they are planned to be loaded in 2022. Advanced technologies for recycling nuclear materials and refabrication of nuclear fuel in the future will make it possible to process irradiated fuel instead of storing it, as well as to reduce the amount of high-level waste generated.”
Serial production of mox fuel began at the end of 2018 at MCC. To achieve this, broad industry cooperation was organised under the coordination and scientific leadership of TVEL, which supplies the mox-fuel to Beloyarsk NPP. Initially, the BN-800 reactor was launched with a hybrid core, partly equipped with uranium fuel produced by Mashinostroitelny Zavod in Elektrostal (Moscow Region), and partly with experimental mox assemblies manufactured at the Research Institute of Atomic Reactors (NIIAR) in Dimitrovgrad, Ulyanovsk region).