Operators at Pacific Gas and Electric Company's Diablo Canyon Power Plant today announced the shut down of Unit 1 in order to perform necessary work on the back-up cooling system. Unit 2 continues to operate at full power.
PG&E made the decision to take Unit 1 offline after routine inspections detected a small buildup of boric acid on the Unit 1 Residual Heat Removal System. This system helps manage reactor coolant temperatures in the unlikely event of an emergency.
Unit 1 will be restored to service after repairs are complete. PG&E has informed the U.S. Nuclear Regulatory Commission and appropriate local and state officials.