The Mayak Production Association (Russian: Производственное объединение «Маяк», Proizvodstvennoye ob′yedineniye "Mayak", from Маяк 'lighthouse') is a nuclear facility near Ozyorsk, Chelyabinsk Oblast, Russia, with production reactors and a reprocessing plant. Its reprocessing capacity, at 400 tonnes of heavy metal per year, is the second-largest in the world, following the La Hague site in France. It is currently used for military and civilian radioisotope production, and was historically central to the Soviet nuclear weapons program. Lavrentiy Beria led the Soviet atomic bomb project. He directed the construction of the Mayak plutonium plant in the Southern Urals between 1945 and 1948, in a great hurry and secrecy as part of the Soviet Union's atomic bomb project. The plant had a similar purpose to the Hanford Site of the Manhattan Project. Over 40,000 gulag prisoners and POWs built the factory and the closed nuclear city of Ozyorsk, called at the time by its classified postal code "Chelyabinsk-40". The first reactor, A-1, operated from 1948 and fuelled the first nuclear test RDS-1 in 1949. During the Cold War, 10 nuclear reactors were constructed, with a combined power of 7,333 MWth. Of these, four were used for plutonium production, yielding 31 tons of weapons-grade plutonium, out of the Soviet Union's all-time production of 145 tons. The other six reactors primarily produced tritium for thermonuclear weapons. In 1990, weapons-grade plutonium production was ceased. As of 2025, Mayak is still active, with two reactors in operation at 1,900 MWth. Today the plant primarily produces tritium for domestic weapons maintenance, and plutonium-238, used by many space programs for radioisotope thermoelectric generators. Many other radioisotopes are commercially sold worldwide, including 14C, 60Co, 137Cs, 147Pm, 193Ir, 237Np, 241Am. Polonium-210 produced at Mayak was reportedly used in the 2006 poisoning of Alexander Litvinenko. It also reprocesses the spent nuclear fuel from civilian reactors, and manages plutonium from decommissioned nuclear weapons. In recent years, proposals that the plant reprocess waste from foreign nuclear reactors have given rise to controversy. The site has had many radiation accidents and radioactive contamination. In 1949–1951, 76 million m3 of toxic chemicals and 3.2 million curies 750 km2 (290 sq mi) of radioactive waste were released into the Techa river. In 1957, the Kyshtym disaster occurred at Mayak, releasing 20 million curies in a radioactive cloud across the eastern Urals. It was the worst nuclear accident in history until the Chernobyl disaster, and is still the third most severe. Mayak is also widely suspected to be the source of the ~200 TBq (~5400 curies) airborne radioactivity increase in Europe in autumn 2017. Between the first two accidents, 38,000 people were evacuated. Many other communities remained exposed, suffering long-term effects of radiation poisoning.
Location
The nuclear complex is 150 km south of Ekaterinburg, between the towns of Kasli and Tatysh, and 100 km northwest of Chelyabinsk. The closest city, Ozyorsk, is the central administrative territorial district. As part of the Russian (formerly Soviet) nuclear weapons program, Mayak was formerly known as Chelyabinsk-40 and later as Chelyabinsk-65, referring to the postal codes of the site.
Design and structure Mayak's nuclear facility plant covers about 90 square kilometres (35 sq mi). The site borders Ozyorsk, in which a majority of the staff of Mayak live. Mayak itself was not shown on Soviet public maps. The location of the site together with the plant city was chosen to minimise the effects that harmful emissions could potentially have on populated areas. Mayak is surrounded by a ~250 square kilometres (97 sq mi) exclusion zone. Nearby is the site of the South Urals nuclear power plant.
Reactors
Notes
History Built in total secrecy between 1945 and 1948, the Mayak plant was the first reactor used to create plutonium for the Soviet atomic bomb project. In accordance with Stalinist procedure and supervised by NKVD Chief Lavrentiy Beria, it was the utmost priority to produce enough weapons-grade material to match the U.S. nuclear superiority following the atomic bombings of Hiroshima and Nagasaki. Little to no consideration was paid to worker safety or responsible disposal of waste materials, and the reactors were all optimised for plutonium production, producing many tons of contaminated materials and utilising primitive open-cycle cooling systems which directly contaminated the thousands of gallons of cooling water the reactors used every day. Lake Kyzyltash was the largest natural lake capable of providing cooling water to the reactors; it was rapidly contaminated via the open-cycle system. The closer Lake Karachay, too small to provide sufficient cooling water, was used as a dumping ground for large quantities of high-level radioactive waste too "hot" to store in the facility's underground storage vats. The original plan was to use the lake to store highly radioactive material until it could be returned to the Mayak facility's underground concrete storage vats, but this proved impossible due to the lethal levels of radioactivity (see Pollution of Lake Karachay). The lake was used for this purpose until the Kyshtym Disaster in 1957, in which the underground vats exploded due to a faulty cooling system. This incident caused widespread contamination of the entire Mayak area (as well as a large swath of territory to the northeast). This led to greater caution among the administration, fearing international attention, and caused the dumping grounds to be spread out over a variety of areas (including several lakes and the Techa River, along which many villages lay).
Kyshtym disaster
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