> OK. I'm kind of there: How about we fire off a classic fission device every 5 years, and power the electricity supply off the heat we soak into the surroundin

> OK. I'm kind of there: How about we fire off a classic fission device every 5 years, and power the electricity supply off the heat we soak into the surrounding rocks? That actually was the original plan, although you needed to detonate one every few days instead of every few years. The initial experiments detonated them in salt mines but the explosions did too much damage and couldn't be reliably contained, so the plan switched to a large steel cavity partially filled with water. Unfortunately the cost of nuclear weapons was far too high to produce power competitively and you'd get a substantial buildup of fission waste. This led to the idea of using lasers instead of fission to initiate the fusion reaction, which in turn developed into modern inertial confinement fusion (ICF). And yes, for tokamaks they are aiming for pulsed energy.