France, a rich, functional, liberal, western democracy, is more or less uncontroversially nuclear powered to a very high degree. There are no more practical difficulties than any other large, important project. The only problem is politics.

I wouldn't say uncontroversially. There are political issues around what to do with aging nuclear power plants (see Fessenheim: https://en.wikipedia.org/wiki/Fessenheim_Nuclear_Power_Plant) and whether to invest more. I don't know much about it, but nuclear energy was a talking point during the latests elections.

Personally, I think it would be an enormous mistake not to invest enough to at least assess the feasibility/practicality of cleaner nuclear sources. I really hope France keeps on investing in nuclear energy & research.

More or less uncontroversially ;)

Especially compared to the fate of nuclear in most other countries around Europe.

That's like saying that building a road is no more difficult than launching a rocket into orbit.

It turns out that nuclear physics is really quite hard. That is not a reason to not do something. But we shouldn't take these issues so lightly.

Of course it's hard. But it's not like we've never done it before and that operating nuclear power plants is this weird theoretical endeavour.

Or, put in another way: the hardness isn't why we're not doing it.

I don't agree. A lot of countries have been open to new nuclear developments. In the UK for example there is a supportive government, and schemes are even quite popular locally due to jobs. Yet the commercial and political risk is still huge. Despite the legacy of nuclear schemes it is still difficult to get schemes of the ground. And those kind of issues are in a large part due to the unqiue challenges that nuclear presents that are not relevant in other large infrastructure projects.

Despite those unique challenges, the French built 56 reactors in the 70s and 80s. GDP had quadrupled since then, while those unique challenges haven't gotten bigger -- but they have been amended with 40 years of rabid FUD. That is the challenge, and as long as politicians are repeating the FUD, it's not going to get easier.

So massive overuns in time and money are due to FUD? Does the explain design flaws? Politicians are used to taking flack for infrastructure projects, that is hardly unique to nuclear. But funding the next generation of reactor is hugely expensive and risky regardless of public perceptions.

Partially, yes. The reactors currently under construction are third generation, as opposed to tested, proved and wildly successful second generation plants (plus tweaks and updates). There are of course many good (and even more really bad) reasons to prefer a new and unproven design over a slightly older proven one, and few of them unique to nuclear projects -- but massive unwarranted fear (including conflation with nuclear weapons) has been the defining narrative of nuclear between 30-40 years ago when we were perfectly capable of building nuclear projects and today.

So why did they choose to not use proven designs? Honestly I don't have a problem using riskier designs if it could reduce costs. And increased complexity is a risk in itself.

It's difficult to say, but it's likely to be a factor that an official expressing a risk tolerance >0.00 would have a very short and unglamorous career ahead of him in the hostile climate surrounding anything nuclear, despite us casually accepting much, much higher risks in all sorts of areas.

I think we have the nuclear physics part figured out. It is more of an engineering challenge.

Implementing the practical considerations sensibly is political, though - see TEPCO's out of date contingency planning for a clear case of regulatory capture.