The BN-800 fast neutron reactor was connected to the grid in December 2015 and will gradually be brought to full capacity after the completion of equipment and systems tests at the 50% power level.
The BN-800 reactor is a sodium-cooled fast breeder reactor, built at the Beloyarsk Nuclear Power Station, in Zarechny, Sverdlovsk Oblast, Russia. Designed to generate electrical power of 880 MW in total, the plant is the final step to the commercial plutonium cycle breeder. The plant started producing electricity December 10, 2015, with a reduced power of 235 MW.
The plant is a pool-type reactor, in which the reactor, coolant pumps, intermediate heat exchangers and associated piping are all located in a common liquid sodium pool. The design of this plant was started in 1983 and was completely revised in 1987 after the Chernobyl Disaster and to a somewhat lower degree in 1993, according to the new safety guidelines. After the second revision, the electric output power was increased by 10% to 880 MW due to the increased efficiency of the planned power generator steam turbines.
The reactor core is, in size and mechanical properties, very similar to the BN-600 reactor core, but the fuel composition is very different. While BN-600 uses medium-enriched uranium dioxide, the new plant will burn mixed uranium-plutonium fuel, helping to reduce the weapon-grade plutonium stockpile and provide information about the functioning of the closed uranium-plutonium fuel cycle. It was highlighted that the closed cycle will not require plutonium separation or other chemical processing.
The unit employs a three-circuit coolant arrangement; sodium coolant circulates in both the primary and secondary circuits. Water and steam flow in the third circuit. This heat is transferred from the reactor core via several independent circulation loops. Each comprises a primary sodium pump, two intermediate heat exchangers, a secondary sodium pump with an expansion tank located upstream, and an emergency pressure discharge tank. These feed a steam generator, which in turn supplies a condensing turbine that turns the generator.