meltdown

English Thesaurus

1. a disaster comparable to a nuclear meltdown (noun.event)

hypernym	:	calamity, cataclysm, catastrophe, disaster, tragedy,
definition	:	an event resulting in great loss and misfortune (noun.event)

2. severe overheating of the core of a nuclear reactor resulting in the core melting and radiation escaping (noun.process)

hypernym	:	overheating,
definition	:	excessive heating (noun.process)