As reported by David R. Baker in the San Francisco Chronicle, "Pacific Gas and Electric Co. replaced $842 million of equipment at the heart of the Diablo Canyon nuclear plant without first making sure the new gear could pass a vital seismic safety test required in the facility’s license, The Chronicle has learned." (See full text of article here.)
The systems, structures and components in question include new lids, as well as replacement steam generators, for the twin unit nuclear power plant. The revelation comes in the aftermath of the permanent shutdown of California's other operating nuclear power plant, San Onofre Units 2 and 3, due to widepsread damage from defective replacement steam generators. That fiasco has turned into a multi-billion dollar boondoggle. More.