Actually yes Soryn I think you must be right about the civil disorder because I was involved in a long war and I had many cities with the unhappy face on them over the war. Perhaps this is what made the meltdowns more likely. I just wish there was a way to control it since it really ruined my entire game once global warming struck.
Also another question, I tried replacing the reactors in my cities with Coal plants. Now in previous civ's I thought that if you build a coal plant and had another plant in there already like nuclear it would automatically replace it, however that didn't happen for me I just simply had a coal plant and a nuclear plant. I tried to destroy or sell the building like you could in civ 3 but wasn't able to. Is there a way to sell/destroy improvments in your cities?
Also another question, I tried replacing the reactors in my cities with Coal plants. Now in previous civ's I thought that if you build a coal plant and had another plant in there already like nuclear it would automatically replace it, however that didn't happen for me I just simply had a coal plant and a nuclear plant. I tried to destroy or sell the building like you could in civ 3 but wasn't able to. Is there a way to sell/destroy improvments in your cities?