On the Moon, I mean.
The US's current plan is emplace a crewed habitat at the lunar south pole [1]. The habitat will need power. Solar power on the Moon has the drawback that the Moon has long nights, two weeks long. The poles offer the option of building a distributed system where at least some of the arrays are in daylight, but this probably involves more infrastructure than an early effort may be able to afford and will involve low sun angles. Nuclear is an obvious solution but atoms scare Americans (Yes, we could work to re-educate the Americans on this but this would undermine sales of Canadian oil to the US and so is clearly counter-productive).
At the same time, the base is going to cost a bundle. Dumping some of the costs on foreign partners may be necessary (The choice may be between a multinational base or no base at all, given that the US is unlikely to deviate from their historical spending levels on space [2]).
Now, which space-faring nations are more comfortable with nuclear power than the US? Let's define "more comfortable" as being willing to get twice as much of their power from atomic energy than the US.
These are the nations which as of last year got 40% of their electricity from atomic reactors:
nation Fraction of electricity
generated by nuclear power
Belgium 55%
Bulgaria 42%
France 78%
Lithuania 72%
Slovak Republic 55%
Sweden 52%
Switzerland 40%
Ukraine 51%
The only nation on that list with the ability to build launchers is France.
If we eliminate the former Warsaw Pact nations (on the basis that their atomic technology tends to be "nightmarishly poorly designed Soviet legacies"), the list is
nation Fraction of electricity
generated by nuclear power
Belgium 55%
France 78%
Sweden 52%
Switzerland 40%
All which are ESA members [Hastily edited because for some reason I thought the Swiss had stayed out of the ESA]. Of those four nations, three have substantial numbers of Francophones.
The way I see it, there's a good chance that the dials on a lunar reactor will have French words on them.
1: 14+ years from now, or as far from us as the Cold War. Continuity of funding is an interesting issue.
2: Which are atypically high for Earth.