There is also an abundance of He3 in the upper crust of the moon. You could centrifuge that out and use it to fuel a D-He3 fusion reactor (assuming you could m

There is also an abundance of He3 in the upper crust of the moon. You could centrifuge that out and use it to fuel a D-He3 fusion reactor (assuming you could make such a reactor work terrestrially, ship millions of tons, and assemble such a facility on the moon). D-He3 is the lowest temperature aneutronic fusion reaction. Not all fast neutron hardening problems go away because a small cross section of reactions will be D-D even at the higher temperature (and potentially short bursts of higher fast neutron flux if temperature control is inadequate and low). However, most of the energy comes out as fast charged particles, which is open to direct conversion. Ditching the steam cycle is a big deal in terms of plant size and weight.