Have some fun ...
A cooling dome on the image at the first post .... in the vacuum ... is everything all right, I guess so ...
Then ... each and every nuclear station on earth , fall under basic Carnot Cycle , where active body , transfer energy from hot side to the cold side, release energy, that transformed, and then cool down even more for efficiency, by water or air cooling such as dome .... That Carnot Cycle give you about 30-40% efficiency , the rest dissipated in a thin air. so - 1000 kW electrical nuclear unit about 4200 kW Thermal power, and 3000 kW dissipating as a waste
Space reactors - same principles, atoms divided , emits energy and absorb by active body, usually liquid metal, then a difference, instead steam turbine, a thermoelectric generator. due to not much temperature different , overall efficiency quite mediocre ... for 1000W thermal power probably 70W electrical .... the rest 900+ watts need to dissipate , usually by emitters, due to vacuum ...
technically gases can be used to spin turbines in a space, Problem A- gas will be lost , need replenish, B- low efficiency due to gas masses, C- heavy spinning turbine not for a long time. D - everything sealed as part A. E- deal with hot gases , that a headache, metals absorb it and changing internal structure , etc ...
if ... thermoelectric .... then 40kW electrical transfer to 500 kW thermal , and rather heat the core of the moon , I have no clue how to dissipate it ...
I think It great, and absolutely doable project, with minimal investment (pen and paper don't cost much), with very solid result ...