With few natural energy resources, maybe they decided to invest in nuclear energy because it gave them more independence, and well not have electric power plants that burn coal must contribute a little to there levels of CO2 be lower than other first world countries so that's an extra, but what happened in Japan sure had to put them to think it twice.
One factor that motivated the French to develop their nuclear industry was possibly the fact that they wanted to avoid any chance of being occupied like they were between 1940 and 1944 in the future. Perhaps the French wanted to use their uranium enrichment plants for both civilian and military purposes.
I had not thought about that a self-destruct button maybe? I don't know, I'm going to be realistic I don't think this project started for ecological reasons, I bet was around the oil crisis of the 70s so it was more towards the economic, but if it has deeper roots and they want to use a weapon that would be badass. Like Iran's nuclear program that was supposed to be to develop a nuclear power plant and then someone said it was to create bombs, I really do not know how that ended.
The same enrichment plants that produce weapons grade (high grade) enriched uranium can also be used to produce reactor grade enriched uranium (much lower).