The State : Shutdown at Rancho Seco

A brief loss or fluctuation in the control room electrical supply is suspected of triggering the second shutdown this year of the controversial Rancho Seco nuclear power plant. Sacramento Municipal Utility District spokeswoman Karen Wilson said the 900-megawatt plant shut down automatically when malfunctioning pumps let abnormal pressure build in the primary coolant system. Initial inspections traced the problem to an “upset to main feedwater pump controls.” Wilson interpreted this as “a fluctuation in (electrical) power” in the automatic system that siphons heat from the nuclear reactor and uses it to drive steam turbines and generate electricity.