RE: What France plans to do with its nuclear waste
Several have suggested that nuclear waste at 194 F could be used to generate useful power. This is unlikely. The waste would reach this temperature over a long time without significant removal of heat to the surroundings. Thereafter, it would stay at or near this temperature for an even longer time (until the radioactive materials have significantly decayed). This nearly constant temperature condition would occur when the rate of heat generation, and the rate of heat dispersal to the surroundings are the same. Both are relatively small. If one tried to remove enough heat from these to do something useful with it, the temperature would drop below 194 F, and the opportunity would be lost. To use something at 194 F to generate useful energy, it would have to maintain 194 F even as heat is removed from it. (And as several have commented, even this is inadequate to do much.) This would requre a heat generation rate that greatly exceeds that of the radioactive waste.
