>>12967635There is a design for a nuclear fusion reactor that requires no new technology, which is the PACER nuclear power plant. This involves exploding low-yeild H-bombs in an underground cavity, and transferring the heat to molten salt. This type of plant is politically difficult, because it requires plutonium bombs, full nuclear explosives, so it makes a proliferation nightmare, but it works to produce fusion energy.
The fusion bombs produce neutrons as a side effect, and this can be used to clean the reactor of dangerous medium half-life isotopes, and do additional transmutations too, and breeding of fissile materials to close the cycle. It is 95% fusion energy even for small bombs. It is economical and practical, but it requires getting our act together regarding safety and politics, so that there is no danger of misuse of the bombs.