Three Mile Island. Perhaps the most famous nuclear accident in the US On March 16, 1979, the movie China Syndrome, based on the effect described in the last slide, was released.
The tank that collected the discharge from the PORV overfilled and the sump pump in the containment building filled and sounded an alarm. This, plus abnormally high PORV T and higher than normal containment building Temperature and Pressure readings were ignored by the operators.
A failure in the quench tank caused radioactive coolant to be pumped into a building outside the containment building.