It's complicated enough that I don't think you could have something fully automated unless it's an RTG.
It would all probably end like Antarctica, we had one reactor down there, but the cost of sending people there just to run it and the infeasibility of any repairs of upgrades ended the entire effort after one generation.
> It would all probably end like Antarctica, we had one reactor down there, but the cost of sending people there just to run it and the infeasibility of any repairs of upgrades ended the entire effort after one generation.
The decision to close McMurdo Station's "Nukey Poo" nuclear power station in 1972 wasn't just due to cost of running it, it was also due to environmental concerns. On the Moon, those environmental concerns don't exist – there is no living environment to be harmed.
Also, Nukey Poo was 1960s technology. State-of-the art nuclear reactors are more reliable and less maintenance-intensive than their 1960s forebears. So just because Nukey Poo required an on-site crew of 25 people, it doesn't necessarily follow a lunar reactor would.
The reactor could be remotely monitored and controlled from Earth, and some maintenance tasks could likely be performed by robots–not possible in Nukey Poo's day. There would still likely be some maintenance tasks that would require humans on-site, but that might require significantly less than 25 people.
For improved safety, a lunar reactor could be situated several kilometres away from the nearest human settlement, and left unattended most of the time. Humans (travelling in pressurised lunar rovers) could visit on those occasions when in-person maintenance was necesary.
Another factor which added to the cost of Nukey Poo – under the Antarctic Treaty, it is prohibited to dispose of nuclear waste in Antarctica, so the whole site had to be disassembled and cleaned-up and all waste shipped back to the US via New Zealand, at great expense. By contrast, a disused lunar reactor could likely just be abandoned in-place.
That's the biggest reason I prefer the Moon to Mars for anything in the next 25-50 years at least. The Moon is close enough to Earth to get supplies quickly in a crunch. Mars is not. It's going to take a long time for anything off-world to be industrially self-sufficient because as you point out supply chains are longer and more complex than people realize.
It would all probably end like Antarctica, we had one reactor down there, but the cost of sending people there just to run it and the infeasibility of any repairs of upgrades ended the entire effort after one generation.