Kind of? I'm sure you can change a nuclear power plant so it doesn't rely on river or sea water but that's not something that can be done overnight.

Restoring river water levels can't be done through technical solutions though, they rely on the weather and we can't control that. The European river levels are largely influenced by inland rain, snowfall, and glacier forming/melting; snowfall and rain has been meagre this year, glaciers have been melting and receding for decades now.

Electricity costs by nuclear power is heavily subsidized by tax money in France, so the French are paying the higher costs anyway. Just saying. Maybe there's a technical solution involving nuclear but it's really expensive compared to the much cheaper technical solution: renewable energy.