Soviet Union. Four underground nuclear explosives (at depths of 975 to 1,060 m) were detonated in quick succession in the Astrakhan gas field in the USSR, creating four underground cavities. The blast yield ranged from 8.5 to 13.5 kilotons. This series of explosions was part of a large-scale Soviet program called “Vega” (Проект “Вега”), which lasted from 1980 to 1984 and consisted of 15 peaceful nuclear explosions to create underground natural gas storage facilities. The program was intended to be radiologically safe and environmentally friendly, and according to official reports, it was. However, due to a variety of factors, the condition of the storage facilities began to deteriorate in 1986, and by 1991, thirteen of them were officially recognized as being on the verge of failure. Since then, the cavities have remained a problem for many agencies that have succeeded in permanently closing the wells.
