The BN-350 was a sodium-cooled fast reactor located at Aktau Nuclear Power Plant. The power plant was located in Aktau (formerly known as Shevchenko in 1964-1992), Kazakhstan, on the shore of the Caspian Sea. Construction of the BN-350 Fast breeder reactor began in 1964, and the plant first produced electricity in 1973. In addition to providing power for the city (150 MWe), BN-350 was also used for producing plutonium and for desalination to supply fresh water (120,000 m³ fresh water/day) to the city.
The project lifetime of the reactor officially finished in 1993, and in June 1994, the reactor was forced to shut down because of a lack of funds to buy fuel. By 1995, the plant's operating license had expired. The facility continued to operate far below capacity until reactor operations ceased in 1999, when plutonium-bearing spent fuel stopped being produced.