First serial batch of MOX fuel loaded into BN-800

28 January 2020

Unit 4 of the Beloyarsk nuclear power plant in Russia's Sverdlovsk district has been restarted after being loaded with the first serial batch of mixed-oxide (MOX) fuel. By 2021, the BN-800 fast neutron reactor should be operating with a full core of MOX fuel assemblies.

The BN-800 reactor at Beloyarsk (Image: Rosatom)

Beloyarsk 4 was initially fuelled with a hybrid core containing both uranium and MOX fuels. The uranium fuel assemblies were produced by Elemash, fuel manufacturer TVEL's major fabrication facility in Elekrostal, near Moscow, while the experimental MOX fuel assemblies had been fabricated at the Research Institute of Atomic Reactors in Dimitrovgrad, in the Ulyanovsk region.

Workers have now loaded 18 MOX fuel assemblies - manufactured by the Mining and Chemical Combine (MCC) in Zheleznogorsk, in the Krasnoyarsk region - into the reactor's core. The production line - located in a mine 200 metres underground - was built as part of Russia's 'Proryv', or Breakthrough, project to enable a closed nuclear fuel cycle. The ultimate aim is to eliminate production of radioactive waste from nuclear power generation. The facility completed tests on putting together the first nuclear fuel assemblies for the BN-800 reactor in August 2015. Serial batch production of MOX fuel started at MCC in late 2018. The basic technology for manufacturing the MOX fuel pellets was developed by TVEL subsidiary AA Bochvar Research Institute of Inorganic Materials. The fuel pellets are manufactured from a mixture of oxides of depleted uranium accumulated at TVEL facilities and oxides of plutonium extracted during the reprocessing of used nuclear fuel.

Plant operator Rosenergoatom and TVEL plan to load another batch of 180 MOX fuel assemblies into the BN-800 during this year. Russian state nuclear corporation Rosatom said it is committed to replace all the remaining uranium-based fuel assemblies in its core with MOX fuel by the end of 2021. "Thus, for the first time in Russian history, a fast neutron reactor would start operations with a full load of MOX fuel only," it said.

"Rosatom's strategy is aimed at the dual-component nuclear power system with both thermal neutron and fast neutron reactors, and closing the nuclear fuel cycle, which would solve a number of highly important tasks," said Vitaly Khadeev, vice president for the development of closed nuclear fuel cycle technologies and industrial facilities at TVEL. "Firstly, this would exponentially boost the feedstock for nuclear power plants. Secondly, this would enable the recycling of used nuclear fuel instead of storage. And thirdly, we once again involve into the nuclear fuel cycle and utilise the accumulated ground stocks of depleted uranium hexafluoride and plutonium."

The BN-800 reactor was brought to minimum controlled power for the first time in June 2014, at which time commercial operation was planned for the end of that year. However, in December 2014 operator Rosenergoatom announced that nuclear fuel for the unit would first be developed further. It was brought again to the minimum controlled power level in August 2015, and again in November 2015, eventually being connected to the grid on 10 December 2015. The 789 MWe reactor entered commercial operation on 31 October 2016.

Fast reactors, fuelled by MOX, vastly increase the efficiency of the nuclear fuel cycle and feature heavily in Russia's long-term nuclear energy plans.

Researched and written by World Nuclear News