Boxer Calls for Justice Department Investigation Into San Onofre
[This story has been updated: see end for details.] U.S. Senator Barbara Boxer, a long-time critic of the troubled San Onofre Nuclear Generating Station north of San Diego, has asked the Justice Department to look into whether plant operator Southern California Edison (SCE) deliberately misled regulators as the utility replaced aging steam generators at the plant's two remaining units.
San Onofre has been shut down since January 2012, when a leak of radioactive steam occurred in the steam generator in it's Unit 3. The utility is seeking federal approval to restart Unit 2 at reduced capacity.
In a press conference Tuesday, Boxer described a letter her office had obtained sent in November 2004 by SCE Vice President Dwight E. Nunn to Akira Sawa of generator manufacturer Mitsubishi Heavy Industries. She said the replacement generators, installed in 2009 and 2010, were signed off on by the Nuclear Regulatory Commission (NRC) under a procedure that allows streamlined review of so-called "like-for-like" equipment replacements in nuclear power plants. Utilities can certify their own equipment replacements as "like-for-like," meaning that any differences between old and new equipment are minimal. The certification allows plant operators to avoid the time-consuming license amendment process, in which the NRC scrutinizes more significant proposed equipment modifications over the course of many months.
Nunn's November 2004 letter to Mitsubishi includes a passage saying that San Onofre's steam generator replacement was in fact not a "like-for-like" equipment swap. The statement was made in the context of modeling seismic response of the new generators in time to make a 2008 delivery deadline:
However, those models aren't ready for use at this time and the design effort must proceed to meet the 2008 delivery date for the steam generators for Unit 2. Consequently, the design of the new steam generators is currently proceeding using the existing steam generator seismic response based on a like-for-like replacement concept (although the old and new steam generators will be similar in many respects they aren't like-for-like replacements). Should there be a significant difference in the seismic response of the old and new steam generators, changes in the steam generator design may be necessary. [Emphasis added.]
Boxer noted that Nunn's letter described the new steam generators as "one of the largest steam generators ever built for the United States," pointing out that this seemed to contradict SCE's "like-for-like" assessment of the new steam generators.
Boxer's charges echo those of the anti-nuclear group Friends of The Earth, which has long accused SCE of playing fast and loose with its self-certification.
Given the phrasing in the letter, it's unclear to ReWire whether Nunn meant to distinguish the size of the new generators from the older ones, or merely from the generators in use throughout the United States. That said, the old and new steam generators at San Onofre did differ in size, with hundreds of new steam tubes designed into the replacement generators, which made the replacements significantly heavier.
In the letter, Nunn points out different ways in which the scale of the new generators may make them more susceptible to the type of wear that led to the January 2012 leak, adding that experimental "Anti Vibration Bars" seemed to actually hasten tube wear at another, unnamed U.S. reactor. "Our discussions with Mitsubishi Heavy Industries to date have not resulted in a plan that will successfully address this industry concern," wrote Nunn. "Both San Onofre and Mitsubishi Heavy Industries are having difficulty in formulating such a plan."
The NRC is now considering an SCE request that San Onofre Unit 2 be restarted at 70 percent of its capacity, a strategy the utility says will "prevent" the vibrations which investigators say was responsible for the tube wear leading to the leak in Unit 3. In all, tube wear was found in about 15,000 places in 3,401 of the replacement generators' steam tubes after the leak was noticed in January 2012.
Boxer says she's provided the Nunn letter to the Justice Department as well as state and federal regulators, and is asking investigators to determine whether SCE's staff "engaged in willful wrongdoing."
"We have a situation here where SCE certified that its steam generator replacement project was a like-for-like," Boxer told reporters Tuesday. "The letter clearly states the project is not like for like. It's extremely disturbing that they would self-certify that this was like-for-like, deceiving the public and the regulators."
Boxer noted that in his letter to Mitsubishi, Nunn described the effect of any leaks in the steam generators as "disastrous." The passage in question:
Based upon these observations, I am concerned that there is the potential that design flaws could be inadvertently introduced into the steam generator design that will lead to unacceptable consequences (e.g. tube wear and eventually tube plugging). This would be a disastrous outcome for both of us.
"Now that there has been leakage from tube wear," said Boxer during the Tuesday press call, "SCE acts as if it's no big deal."
ReWire has offered SCE the opportunity to reply to Senator Boxer's announcement, and we'll update you when they do. Until then we'll have to make do with a response provided to the Associated Press in which SCE's Chief Nuclear Officer Pete Dietrich defended the utility. "These documents demonstrate the type of careful oversight that SCE exercised during the replacement steam generator project," Dietrich said, "and also served to establish our expectations of {Mitsubishi]. SCE would never, and did not, install steam generators that it believed would impact public safety or impair reliability."
UPDATE: SCE has responded with a statement and accompanying background material on NRC procedures. ReWire will cover SCE's response in some depth on Wednesday morning.
