Cost is also a factor, though (sorry, not throwing it in as a counter-argument late in the say). Cost of operation was a factor in us not going nuclear.She's one of only four classes of CVN ever built and the only nuclear-powered surface warship ever designed and built in W Europe. It's arguable that on that basis, she's been a roaring success. It's fair to say that aside from the shielding issue they had to redesign for, none of her other issues are related to her plant.
The French paid the UK £100M for the design rights to QEC, back in the day. A good point to start from whether they opt for kettles or not. Might be a bit tricky to work them in given QEC propulsive layout, but I'd be surprised if they haven't been thinking about it for a few years.