All together, the Program 7 conducted 115 nuclear explosions. Among them:
39 explosions for the purpose of geological exploration (trying to find new natural gas deposits by studying seismic waves produced by small nuclear explosions)
25 explosions for intensification of oil and gas debits
22 explosions for creating underground storage for natural gas
5 explosions for extinguishing large natural gas fountains
4 explosions for creating channels and dams (including the Chagan test in Kazakhstan, and the Taiga test on the potential route of the Pechora-Kama Canal)
2 explosions for crushing ore in open-pit mines
2 explosions for creating underground storage for toxic wastes
1 explosion to facilitate coal mining in an underground mine 19 explosions were performed for research purposes (studying possible migration of the radioactivity from the place of the explosions).
These explosions were financed by various ministries: 51 explosions were financed by the Ministry for Geology, 26 explosions were financed by the Ministry for Natural Gas, 13 explosions were financed by the Ministry for Oil, 19 explosions were financed by the MinSredMash itself (the predecessor of the Federal Atomic Energy Agency). There were two large explosions of 140 kilotons and 105 kilotons; all others were relatively small with an average yield of 12.5 kilotons. For example, one 30 kiloton explosion was used to close the Uzbekistan Urtabulak gas well in 1966 that had been blowing since 1963, and a few months later a 47 kiloton explosive was used to seal a higher pressure blowout at the nearby Pamuk gas field, successful experiments later cited as possible precedents for stopping the Deepwater Horizon oil spill.[3][4][5][6]
The last nuclear explosion by the Program 7, codenamed Rubin-1 was performed in Arkhangelsk oblast on September 6, 1988. The explosion was a part of a seismic program for geological exploration. The Soviets agreed to stop their PNE program at the end of 1988 as a result of then president Mikhail Gorbachev's disarmament initiative.
There are proponents for continuing the PNE programs in modern Russia. They (e.g. A. Koldobsky) state that the program has already paid for itself and saved the USSR billions of rubles and can save even more if it would continue. They also allege that the PNE is the only feasible way to put out large fountains and fires on natural gas deposits, and it is the safest and most economically viable way to destroy chemical weapons.
Cold Heat, you are the man!
It is funny how few of the USSR tests ever get talked about.
I was surprised the that the only LIVE ICBM test was an SS18 and a +1MT warhead.
We launched a live sub missile but the warhead and range was much less.