Temperatures above 50C used to be a rarity confined to two or three global hotspots, but the World Meteorological Organization noted that at least 10 countries have reported this level of searing heat in the past year: the US, Mexico, Morocco, Algeria, Saudi Arabia, Kuwait, Iran, Pakistan, India and China.
In Iran, the heat index – a measure that also includes humidity – has come perilously close to 60C, far above the level considered safe for humans.
Heatwaves are now commonplace elsewhere, killing the most vulnerable, worsening inequality and threatening the wellbeing of future generations. Unicef calculates a quarter of the world’s children are already exposed to frequent heatwaves, and this will rise to almost 100% by mid-century.
The problem is that there a major, major shortage of one of the isotopes needed to re-enrich weapons grade uranium (pu 238). Thats before you get to the vast energy inefficiency of doing it which isn't a problem, if you're just decommissioning them anyway and you don't care about energy consumption. However, in this instance, you would need to worry about energy consumption as well as the isotope there won't be enough of to convert even a fraction of it.
Again, even if you had 100 years, there aren't enough of the specialist minerals needed for hydro storage and renewables.