There was a project to collect energy from thermonuclear bombs by blowing them up in an underground chamber cooled by a shower of molten salt. It was abandoned

There was a project to collect energy from thermonuclear bombs by blowing them up in an underground chamber cooled by a shower of molten salt. It was abandoned because the cost of making the bombs was too high, not the energy capture. https://en.m.wikipedia.org/wiki/Project_PACER https://en.m.wikipedia.org/wiki/Project_PACER