Check out this 1970s project that proposed extracting electricity from thermonuclear explosions.

https://en.wikipedia.org/wiki/Project_PACER

> A series of 50-kiloton bombs would be dropped into the cavern and exploded to heat the water and create steam. The steam would then power a secondary cooling loop for power extraction using a steam turbine. Dropping about two bombs a day would cause the system to reach thermal equilibrium, allowing the continual extraction of about 2 GW of electrical power