This is a bit far fetched but…
imagine a giant steel container. A hollow sphere, say 5 miles in circumference filled with water. In the center you set of an H-Bomb. The H bomb vaporizes the water and now you have a giant sphere with steam at very high pressure. Then release the steam to power generators.
I know there is no practical way to build a sphere to contain such an explosion. But say we had some type of exotic material that could. And the material was a good insulator so that the heated steam would not radiate the heat from the steam through the material as a metal would. Would using an H bomb to vaporise vast quantities of water to build a giant steam engine be a good energy source?
Is there any way to calculate how many megawatts of energy could be obtained from a 1 megaton H bomb converting its heat energy to steam?