A federal inspector says the Nuclear Regulatory Commission missed opportunities to spot potential trouble with an equipment swap that led to the installation of faulty machinery in a Southern California nuclear plant.
The San Onofre plant was closed last year by Southern California Edison after a battle over whether it was safe to operate. It had been idle since 2012, after a small radiation leak led to the discovery of excessive wear in tubing inside virtually new steam generators.
A report Tuesday by the NRC's Inspector General said a 2009 agency inspection failed to recognize "shortcomings" in the way the swap of steam generators was evaluated.
It also raises questions about why Edison was allowed to install the new generators without seeking a change in its federal operating license.