BN-800 is a sodium-cooled fast neutron power reactor with an electrical output of 800 MW, forming the core of the fourth power unit at the Beloyarsk Nuclear Power Plant in Sverdlovsk Region. It entered commercial operation in 2014; on September 22, 2022, it was brought to full design power for the first time with a complete loading of MOX fuel.[1] The reactor's Nizhny Novgorod connection is its developer, OKBM Afrikantov, located in Nizhny Novgorod.

Principle of operation and fuel

Unlike conventional "thermal" reactors, the BN-800 uses no neutron moderators — neither water nor graphite — which is what the term "fast neutrons" refers to. The coolant is liquid sodium, which, however, reacts violently with water and burns in air, complicating any accident involving a leak.[1]

From the outset, the reactor was designed for MOX fuel (Mixed-Oxide fuel) — a mixture of plutonium and uranium oxides produced at the Mining and Chemical Combine in Zheleznogorsk, Krasnoyarsk Krai. At the initial loading in 2014, MOX fuel made up only 16%; in January 2021 its share rose to one third, in early 2022 to two thirds, and in September 2022 the core was switched to 100% MOX fuel.[1]

The fundamental advantage of fast neutron reactors is their ability to close the nuclear fuel cycle: spent fuel is converted into new fuel, which in theory eliminates the problem of nuclear waste. Besides plutonium, the reactor can use uranium-238, whose reserves, according to specialists' calculations, would last for more than three thousand years.[1]

Global context

The first sodium-cooled fast neutron reactor was the American EBR I, started up on December 20, 1951, but it was never connected to the power grid and was shut down in 1965. Attempts to build commercial fast reactors were made by France (the Phénix reactor, which entered commercial operation in 1974 and was finally shut down in February 2010 without ever reaching its design power), Japan (the Monju reactor — a major sodium leak in 1995, after which, following years of repairs and a repeat accident, the reactor was shut down), and India (the PFBR-500 demonstration reactor, whose startup has been repeatedly postponed). Private nuclear plant owners in the United States see no commercial advantages in fast reactors over thermal ones.[1]

The Nizhny Novgorod connection: OKBM Afrikantov

The lead developer of the BN-800 reactor is OKBM Afrikantov — the Nizhny Novgorod experimental design bureau of mechanical engineering, specializing in reactor plants for nuclear power stations and ships. It was this enterprise that designed the reactor plant, and it is responsible for its technical support throughout the entire life cycle.[1]

Sources

  1. all-pribors.ru — 52763-13: BN-800 Sodium Flow Measurement Systems through the Reactor's Main Circulation Pump 1 (GTsN-1) — Manufacturers, Suppliers, and Verifiers
  2. spktb.ru — To the Fast Guy
  3. urfu.ru — The BN-1200 Reactor Will "Fit" Within the Dimensions of the BN-800 Building
  4. institutcl.cz — Russia Takes a Step Toward the Energy of the Future
  5. atomic-energy.ru — The Launch of the CEFR Reactor Is the Result of Many Years of Cooperation with China — Atomic Energy 2.0
  6. epumps.ru — Joint-Stock Company "Afrikantov Experimental Design Bureau of Mechanical Engineering"