Yes, what I mean is that theoretically you could do something like have a very very wide base to passively dump heat into the ground (since we're still only looking at kW scale reactors in space), or actively cycle large amounts of regolith through the cooling loop (say, via a heat exchanger from a closed water loop) and dump it out. Depending on how much heat the system can handle, you could maybe even extract stuff boiling off from the regolith.

The nuclear plant nearest to me uses sea water, which is put back into the ocean.

Interesting. I had to look for more details. I found this link https://nuclear.duke-energy.com/2013/11/13/why-don-t-all-nuc...

Oversimplifiying: All new plnats have cooling towers, so the water they return to the environment is not too hot.