BN-600

The BN-600 reactor is a sodium cooled fast breeder reactor built at the Beloyarsk Nuclear Power Station, in Zarechny, Sverdlovsk Oblast, Russia. Designed for 600 MW (electric), it produces 560 MW (electric) dispatching energy to the Middle Urals power grid. It has been in operation since 1980.

The plant is a poll-type reactor, where the reactor, coolant pumps, and intermediate heat exchangers and associated piping are all located in a common liquid sodium pool. The reactor system is housed in a concrete rectilinear building, and is provided with filtration and gas containment features. There have been incidents involving sodium/water interactions from tube breaks in the steam generators, a sodium fire from a leak in an auxiliary system, and a sodium fire from a leak in a secondary coolant loop while shut down. All of the incidents were classified as the lowest level on theInternational Nuclear Event Scale, and none of the events prevented restarting operation of the facility after repairs.

The reactor core is 1.03 meters tall and has a diameter of 2.05 meter. It has 369 fuel assemblies, mounted vertically, which each consist of 127 fuel rods with an enrichment of 17–26% ²³⁵U. In comparison, the normal enrichment in other Russian reactors is between 3–4% ²³⁵U. The control and scram system comprises 27 reactivity control elements including 19 shimming rods, two automatic control rods, and six automatic emergency shut-down rods. On-power refuelling equipment allows for charging the core with fresh fuel assemblies, repositioning and turning the fuel assemblies within the reactor and changing control and scram system elements remotely.

The unit employs a three-circuit coolant arrangement; the primary and secondary circuits coolant is sodium. Water and steam flow over the third circuit. The sodium is heated to 550 °C in the reactor. This heat is transferred from the reactor core via three independent circulation loops each comprising a primary sodium pump; two intermediate heat exchangers a secondary sodium pump with an expansion tank located upstream; an emergency pressure discharge tank. These feed a steam generator which in turn supplies a condensing turbine which turns the generator.

There is a lot of international interest for the fast-breeder reactor in Beloyarsk. Both Japan and France have their own fast-breeder reactors in operation, though only as test versions. Japan has paid 1 billion for the technical documentation on the reactor in Beloyarsk. It is an international study in progress where Russia, France, Japan, and the United Kingdom participate.