During the Cold War the Soviet Union created at least ten closed cities, known as Atomgrads, in which nuclear weapons-related research and development took place. After the dissolution of the Soviet Union, all of the cities changed their names (most of the original code-names were simply the oblast and a number). All are still legally "closed", though some have parts of them accessible to foreign visitors with special permits (Sarov, Snezhinsk, and Zheleznogorsk).
| Cold War name | Current name | Oblast | Established | Primary function(s) |
|---|---|---|---|---|
| Arzamas-16 | Sarov | Nizhny Novgorod Oblast | 1946 | Weapons design and research, warhead assembly |
| Sverdlovsk-44 | Novouralsk | Sverdlovsk Oblast | 1946 | Uranium enrichment |
| Chelyabinsk-40 and later 65 | Ozyorsk | Chelyabinsk Oblast | 1947 | Plutonium production, component manufacturing |
| Sverdlovsk-45 | Lesnoy | Sverdlovsk Oblast | 1947 | Uranium enrichment, warhead assembly |
| Tomsk-7 | Seversk | Tomsk Oblast | 1949 | Uranium enrichment, component manufacturing |
| Krasnoyarsk-26 | Zheleznogorsk | Krasnoyarsk Krai | 1950 | Plutonium production |
| Zlatoust-36 | Tryokhgorny | Chelyabinsk Oblast | 1952 | Warhead assembly |
| Penza-19 | Zarechny | Sverdlovsk Oblast | 1955 | Warhead assembly |
| Krasnoyarsk-45 | Zelenogorsk | Krasnoyarsk Krai | 1956 | Uranium enrichment |
| Chelyabinsk-70 | Snezhinsk | Chelyabinsk Oblast | 1957 | Weapons design and research |