Southern California Edison (SCE) has responded to charges by Senator Barbara Boxer that the utility may have misled regulators about the scope of the steam generator replacement at its San Onofre Nuclear Generating Station, and the utility's characterization of the events leading to the replacement couldn't be more different from the Senator's.
In a series of statements this week, Senator Boxer said that a November 2004 letter from SCE Vice President Dwight E. Nunn to Akira Sawa of generator manufacturer Mitsubishi Heavy Industries (MHI) offered evidence that SCE had later misled regulators at the Nuclear Regulatory Commission (NRC), which agency was charged with ensuring that changes to San Onofre wouldn't pose a public safety risk.
Those new steam generators, which were substantially larger than the ones they replaced, caused big problems for SCE and San Onofre. Premature wear in the generators' steam tubes apparently contributed to a leak of radioactive steam from one of the new generators in the plant's Unit 3 in January 2012. Unit 2 was shut down for maintenance at the time: both units have remained offline since.
The Boxer announcements come as SCE is waiting on a decision from the NRC over a proposed low-power restart of San Onofre's Unit 2, which the utility says will "prevent" the vibrations that caused the unexpected degree of tube wear.
In the letter, Nunn states that the new steam generators MHI was designing for San Onofre would not be a "like-for-like" replacement of the generators being retired. Boxer charged this week that SCE had subsequently described the steam generator replacement as a "like-for-like" replacement, a term of art that allows nuclear plant operators to avoid seeking a costly, time-consuming license amendment from the NRC.
But SCE says that the Senator has made a "fundamental error" in her reading of the history of the plant. Rather than certifying that San Onofre's replacement generators were a "like-for-like" replacement, says the utility, SCE sought and obtained a permit to replace the generators under a section of the NRC's rules covering Changes, tests and experiments in nuclear power plant design.
"In the November 2004 letter," said SCE in a statement released Tuesday, "SCE emphasized the care that would be needed during the design phase because of the differences between the new and old units. These differences -- which were intended to improve the overall performance of the new units -- were permitted under the NRC's 50.59 process, which allows changes to a nuclear facility if certain criteria are met. Contrary to Sen. Boxer's suggestion, Section 50.59 does not require that replacement equipment be 'like for like' or identical to the equipment being replaced."
The weeds get a little thick in the regulatory jargon here, so bear with us. The "changes, tests, and experiments" rule -- the above-mentioned Section 50.59 -- offers plant operators a way around the license amendment process if it can show NRC that changes to a nuclear power plant neither require a change to the plant's technical specifications nor increase safety risk from operating the plant.
Technical specifications for nuclear power plants offer some leeway in actual performace. This means that renovation of a nuclear plant under Section 50.59 is a bit less restrictive than going for a like-for-like replacement, inasmuchas the NRC's parameters for signing off on a like-for-like replacement is that the equipment at issue be -- in the NRC's blunt definition -- "identical."
"SCE advised the NRC that the San Onofre steam generators contained a number of different features from the previous design," SCE said yesterday. "At no time did SCE hide the differences from the NRC, nor did it seek to mislead the NRC concerning the applicability of Section 50.59 to the project. Any suggestion that seeks to draw from the November 2004 letter a contrary conclusion is simply incorrect and relies on the fundamental error of viewing Section 50.59 as applying to identical, or "like for like" replacements."
SCE's got the upper hand on this particular conflict, it would seem: their use of Section 50.59 is a matter of public record. In fact, the antinuclear group Friends of the Earth petitioned the NRC a year ago to request a hearing on the possibility that SCE violated Section 50.59 by not fully disclosing design changes in the steam generators.
In other words, It would seem at first glance that the facts are on SCE's side in the "like-for-like" issue.
Senator Boxer announced yesterday that her office had referred the Nunn letter to the Department of Justice and state and federal regulators, suggesting that further investigation might be prudent. Unless the Department of Justice broadens the scope of an investigation considerably beyond the Nunn letter, it's unlikely that more than a form letter thanking the senator for her interest will result.