In the Soviet and other totalitarian systems the government could build wherever the hell they wanted, so their decision making is really far from exemplary. I have no idea why would you build an NPP so close to densely populated areas these days, if you have other options. I can see the issue in a smaller and densely populated country like Netherlands, but not in France which is quite more spacious.

A hundred years ago you could happily buy all sorts of drugs in your local pharmacy, but it doesn't mean it was healthy for people. We came a long way with the safety standards and general attitude towards safety. So, the point here is: embrace it instead of looking for excuses. There really were better sites to build the Belarusian NPP, but they built it in violation of the Espoo convention instead of embracing safety and cooperation with your neighbours.

P.S. It is an official recommendation by the Association of Regulators of Western Europe (WENRA) to avoid building NPPs closer than 100 km to the big cities. WENRA was established in 1999, though, so it's relatively recent.