The San Onofre Nuclear Generating Station is seen from the beach south of San Clemente, California.
The manufacturer of steam generators at California's shuttered San Onofre nuclear power plant and the utility that runs the facility will be cited by federal regulators for a flawed design.
Southern California Edison says it was told Friday by the Nuclear Regulatory Commission to expect a citation for failing to make sure computer modeling and analysis were adequate for the design of the steam generators.
The NRC also plans to issue a notice of non-conformance against the manufacturer of the steam generators, Mitsubishi Heavy Industries.
The Southern California plant was shut down last year because of excessive wear in tubes that carry radioactive water and has since been formally retired.
NRC inspectors found a computer code used to model the movement of heat and steam through the generators was flawed.