The USSR had a whole program to investigate peaceful nuclear explosions (PNEs), called Nuclear Explosions for the National Economy. [1] Sadly, some of these experiments went rather wrong, unexpectedly releasing lots of radioactive nasty near populated areas. The US also did this sort of thing from 1961 to 1973, and the program was cancelled in '77. [2]
[1] http://en.wikipedia.org/wiki/Nuclear_Explosions_for_the_Nati...