Introduction: The Manprint Philosophy

On March 28,1979, the central control room operators were alerted to a loss of feedwater to the pressurized water reactor (PWR) of the Three Mile Island Unit 2. The safety injection pumps came on automatically to pump in auxiliary water to the reactor vessel. The indicators for the pressurized vessel, however, showed a dangerous “water-solid” condition for the pressurized vessel. In an attempt to reduce the pressurizer water level, the operators turned off the safety injection pump. Consequently, the reactor core water cover became depleted, leading to a near meltdown. As a result, the nuclear industry radically changed its management and organizational approaches to nuclear safety, but has never fully recovered from the effects of the accident or alleviated the public concerns with nuclear energy.