James Krellenstein, co-founder of Alva Energy, explains precisely what happened at the Three Mile Island accident, in which an ordinary reactor trip cascaded into a partial meltdown due primarily to errors in the human-machine interface. Krellenstein discusses how the 1979 incident, despite its severity, actually showed the effectiveness of the “defense in depth” principle and led to significant improvements in plant operations and nuclear safety culture. Watch the episode on YouTube to follow along with visuals.