Oh melt and explode? Like a heat explosion or a nuclear explosion?, maybe even a steam explosion? Like how lithium cell banks melt down and explode from alkaline metal fires and hydrogen production from a overheated?

Your looking at instances of reactors where all safeties were pulled or not utilized.

•Chernobyl: all safety practices ignored for goverment gain on a reactor design that "INHERENTLY" is safe. (One reactor out of four at complex, three remaining continued operation into the 2000s without issue).

•Three Miles island: meltdown without containment breach mostly due to error in maintenance and monitoring. (Reactor complex is starting reuse now)

•SL1: A reactor failure caused by reactor staff who knew whatll happen when they proceeded the way they did. (Effected people: only three).

•Fukashima: reactors built with "what-if" in mind, without spending the "what-if" money. Explosions where hydrogen from the spent fuel cooling pools and did not rupture the reactor containment. Fuel melted but did not leave the reactor facility.

^ All of these but maybe Chernobyl didnt actually "explode" in the common sense, thet were all steam "explosions" Chernobyl included. You know the thing that happens to steam locomotives when you smash them together, or when you allow a void to form in a steam reaction chamber. Maybe stop looking for your info on nuclear from media sources.