Sen. Barbara Boxer (D-Calif.) on Tuesday called for a federal investigation to determine whether Southern California Edison (SCE) intentionally misled regulators regarding the installation of faulty steam generators at the beleaguered San Onofre Nuclear Generating Station.
Sen. Boxer released a November 2004-dated letter from SCE to Mitsubishi Heavy Industries (MHI), the manufacturer of the replacement steam generators, that she alleges indicates SCE misled regulators to avoid a lengthy and costly review of its plans to install the new steam generators. She also released a June 2005 letter that she alleges suggests the company had raised concerns about aspects of the generator design that could impact tube wear.
The senator said she plans to provide that correspondence to federal and state officials, including the U.S. Department of Justice, so they can determine whether Edison engaged in willful wrongdoing.
"The correspondence shows that Edison knew they were not proceeding with a simple ‘like-for-like’ replacement as they later claimed," Boxer said. "In Edison’s own words, ‘[t]his will be one of the largest steam generators ever built. . . . It will require Mitsubishi Heavy Industries to evolve a new design beyond that which they currently have available’. . . [they] aren’t ‘like-for like-replacements’. . . . Ultimately, Edison asserted that the replacement was ‘like-for-like’, enabling them to avoid a full license review and a public hearing."
Boxer also alleged that the letters show that Edison acknowledged a failure of the steam generators due to tube wear and the need for tube plugging would be a "disastrous outcome."
"Now that this precise failure has occurred, and there has been a leak of radioactive material, Edison claims that it could simply restart the nuclear plant at 70 percent capacity, and once again circumvent the full safety and licensing process. How could they first assert that tube failure would be a ‘disastrous outcome’ and now claim that it is no big deal?" she said.
In a statement on Tuesday, SCE countered that the letters showed it exercised "responsible oversight" of the vendor of the San Onofre nuclear plant replacement steam generators before any designs were completed or approved.
“In response to Sen. Boxer’s statement, we believe that the determination for restart must be made based on technical merits, through the established nuclear regulatory process,” said Pete Dietrich, SCE senior vice president and chief nuclear officer.
“SCE’s own oversight of MHI’s design review complied with industry standards and best practices.” He added: “SCE would never, and did not, install steam generators that it believed would impact public safety or impair reliability.”
The letters "emphasize the importance of careful attention to the design of the steam generators," SCE said. Recognizing that SCE was not the designer of the steam generators and that there were limitations on the assistance SCE could provide, the letters identify a number of design issues that SCE asked MHI to focus on to ensure that design flaws were not inadvertently introduced, it said.
The twin-reactor plant’s Unit 2 has been shut down since Jan. 9, 2012, for a planned refueling and maintenance outage; SCE operators performed a rapid shutdown of Unit 3 on Jan. 31, 2012, after a leak was detected at one of that unit’s steam generator tubes.
For both units, this was the first cycle of operation with new replacement steam generators from MHI that cost $671 million: Unit 2 replaced its steam generators in January 2010 and Unit 3 in January 2011. Each steam generator has 9,727 steam generator tubes, and the new equipment is intended to last until the plant’s license expires in 2022.
MHI last year told POWERnews that its top priority is the safe and reliable operation of all the plants and components it designs, engineers, and supports. "The steam generators in Units 2 and 3 at San Onofre were designed in line with our customer’s specific needs and with customer input, using the best-available data and established industry standards," it said.
The utility proposed to the Nuclear Regulatory Commission (NRC) restarting Unit 2 and operating it at a maximum of 70% power for five months, then taking it down and inspecting it. The utility’s decision on whether or not to retire one or both units hinges on the NRC’s decision on that proposal. Units 2 and 3 use Combustion Engineering pressurized water reactors and have total generating capacities of 1,172 MW and 1,178 MW.
Sources: POWERnews, EPW Committee, SCE