What is MBIR?
The MBIR is being built at the Research Institute of Atomic Reactors (RIAR) site at Dimitrovgrad, in Russia's Ulyanovsk region. It will be the most powerful research reactor in the world, at 150 MWt. It will be a multi-loop research reactor capable of testing lead, lead-bismuth and gas coolants, and run on MOX (mixed uranium and plutonium oxide) fuel. RIAR intends to set up on-site closed fuel cycle facilities for the MBIR, using pyrochemical reprocessing it has developed at pilot scale.
The MBIR is scheduled to begin operation in 2027 and replace the BOR-60 experimental fast reactor that started operations at RIAR's site in 1969. It will have a design life of 50 years and "will expand the study of dual-component nuclear energy technologies and closing the fuel cycle, and will also help accelerate and justify the creation of safe Generation IV nuclear power plants".
The pilot fuel
Specialists at RIAR have manufactured the pilot fuel elements with vibropacked MOX fuel. MOX - mixed oxide - fuel is a nuclear fuel consisting of isotopes of uranium and plutonium. Rosatom says the raw materials for the production of MOX fuel are plutonium oxide obtained during the reprocessing of used nuclear fuel from traditional reactors, and depleted uranium oxide which Rosatom says is "obtained by defluorination of depleted uranium hexafluoride - DUHF, the so-called secondary 'tails' of enrichment production".
Alexander Svyatkin, head of the fuel technology department at RIAR, said: "In the future, these fuel elements will be part of the standard fuel assemblies used in the active zone of the MBIR reactor being built at the institute's site. This fuel element design ensures a high neutron flux density in the active zone, which makes MBIR the most attractive device for conducting reactor tests."
What's next for MBIR?
The dome was installed on the reactor building in October 2023 and the scheduled start of operations is 2027. Rosatom calls it "the most important project for the long-term development of the experimental base of the domestic nuclear industry, which will ensure Russia’s leadership in the development of innovative reactor technologies for the next half century".
