SAN DIEGO – The chief of the Nuclear Regulatory Commission said today that it is investigating whether information provided by Southern California Edison on the San Onofre Nuclear Generating Station has been complete and accurate.
NRC Chairwoman Allison MacFarlane made the comment in a response to a letter from Sen. Barbara Boxer, D-Calif., and Rep. Edward Markey, D-Mass. sent Wednesday.
The elected officials alleged that a document provides ”alarming” evidence that the utility and Mitsubishi Heavy Industries knew that steam generators installed at the plant in northern San Diego County in 2009 and 2010 were problematic.
They said the manufacturer, MHI, authored the cited document.
A steam pressure tube in one of the reactors sprang a small leak a little more than a year ago, forcing the unit to be shut down. The other reactor wasn’t operating at the time due to scheduled maintenance.
Neither has been restarted.
”On September 28, 2012, the NRC’s Office of Investigations initiated an expansive investigation of the completeness and accuracy of information that Southern California Edison provided to the NRC regarding the steam generators at SONGS,” MacFarlane wrote. ”This NRC investigation is ongoing, and includes examination of the MHI report along with other evidence.”
She said the agency is using a variety of regulatory actions, including inspections and investigations, to address the plant’s issues. A study of the MHI document is being evaluated as part of a review of SCE’s replacement of the steam generators.
Opponents of a plan to restart the reactor that had been undergoing maintenance at the time of the leak contend the utility should have had to go through a rigorous license amendment process before the new steam generators were installed, because they were of a different design.
Boxer reacted to MacFarlane’s response by saying the investigations were a ”critical factor” in determining whether it was safe to restart the reactors. An NRC decision on a restart is scheduled for late April or early May.
SCE said Wednesday that it is taking the allegations in the Boxer-Markey letter seriously.
”SCE is fully cooperating with the NRC review process and is complying with all requests for information and documents related to the company’s San Onofre Nuclear Generating Station,” the utility said in a statement. ”The plant has provided voluminous records, data, information and other accurate reports as requested in the months since the plant was safely shut down.”