What is Three Mile Island and what really happened?

Three Mile Island Disaster Nuclear Three Eyed Fish Mutation

The US Nuclear Regulation Commission states that the the plant experienced a failure in the secondary non-nuclear section of the plant, one or two reactors on the site. Either a mechanical or electrical failure prevented the main feedwater pumps, component in the animated diagram, from sending water to the steam generators that remove heat from the reactor core. This caused the plant’s turbine