SAN ONOFRE REPORT FAULTS OVERSIGHT BY REGULATORS -- ’09 inspection cited as ‘missed opportunity’ to identify weaknesses in generator project
Union Tribune (2014-10-08) Morgan Lee
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U.S. nuclear safety regulators missed red flags in 2009 when they agreed to pre-approve steam generators at the San Onofre nuclear plant without a thorough review, leading to the installation of faulty equipment, according to a federal inquiry released Tuesday.
San Onofre was permanently shut down last year by plant operator Southern California Edison because of the rapid degradation of newly replaced steam generators.
In a 55-page report, the Office of the Inspector General at the Nuclear Regulatory Commission said a 2009 inspection by the agency failed to recognize “shortcomings” in the way the replacement of the huge steam generators was evaluated. It also raised questions about why Edison was allowed to install new generators without seeking a change in its federal operating license.
The inspection team from the Nuclear Regulatory Commission reviewed a decision by Edison to replace San Onofre’s steam generators without prior approval from the agency, the report said. No objections were raised by the nuclear commission at the time, and installation of the new generators began in September 2009.
Edison installed the generators under a frequently used rule that allows plant operators to replace equipment without prior approval, provided they can show the switch does not cause significant changes to plant operation or safety.
A subsequent review, after the plant broke down, turned up questions about shortcomings in Edison’s evaluation of changes to the original generator design and whether there was sufficient evidence to sidestep a license amendment, which can take months or years to complete.
The inspector general’s report characterized the 2009 inspection as a “missed opportunity” to identify weaknesses in Edison’s screening of the project, and said there was “no assurance the NRC reached the correct conclusion” when it agreed that a license amendment wasn’t needed to replace the generators.
Edison is reviewing the report and had no immediate comment.
Elmo Collins, the former regional administrator overseeing San Onofre until March 2013, told investigators that if a lengthier license amendment review had been conducted, it is unlikely the steam generators would have been approved.
“The steam generators as designed were basically unlicensable,” he said. “We wouldn’t approve them.”
He said a more thorough review may have prompted probing questions about predictions on steam velocities. Rapid wear among generator tubes at San Onofre was linked to dry, fast-moving steam.
“Some reviewer would have said this is an outlier and we need to understand that,” the inquiry report said, paraphrasing Collins.
Sen. Barbara Boxer, D-Calif., faulted both Edison and the nuclear commission and said a hearing is planned before the Senate Environment and Public Works Committee. Boxer heads the committee, which oversees safety regulations for U.S. nuclear plants.
“When Southern California Edison decided to completely replace their steam generators in order to increase their profit margin, they failed to apply for an amended license as they are required to do, and the NRC stood by and did nothing,” Boxer said in a statement.
The inquiry report shows that some inspectors on the 2009 team were in the midst of training on how to evaluate whether a major reactor component replacement, such as a steam generator, can go forward without a re-evaluation of the plant’s safety systems. Many experts within the agency said better training and guidance is needed.
Steam generators are routinely replaced at nuclear reactors because of corrosion and wear and tear. Since 1989, 53 of the 65 plants that utilize steam generators have replaced their generators without prior approval by the commission.
Six replacements have been made following the license amendment process.
NRC spokeswoman Lara Uselding said the agency was reviewing the report.
Federal authorities traced the generator problems at San Onofre to botched computer codes used to design the generators.
Previously, the commission cited Mitsubishi Heavy Industries for flawed computer codes used in the design of the steam generators. Edison was cited for failing to properly check the design.