The full text of the letter is below:
The Honorable Allison M. Macfarlane
Nuclear Regulatory Commission
11555 Rockville Pike
Rockville, MD 20852
Dear Chairman Macfarlane:
We have become aware of new information contained in a 2012 Mitsubishi Heavy Industries (MHI) document entitled "Root Cause Analysis Report for tube wear identified in the Unit 2 and Unit 3 Steam Generators of San Onofre Generating Station" (Report).
We strongly urge the Nuclear Regulatory Commission (NRC) to promptly initiate an investigation concerning the troubling information contained in this Report.
The Report indicates that Southern California Edison (SCE) and MHI were aware of serious problems with the design of San Onofre nuclear power plant's replacement steam generators before they were installed. Further, the Report asserts that SCE and MHI rejected enhanced safety modifications and avoided triggering a more rigorous license amendment and safety review process.
For example, the Report states that although SCE and MHI accepted some adjustments to the replacement steam generators, further safety modifications were found to have "unacceptable consequences" and were rejected: "Among the difficulties associated with the potential changes was the possibility that making them could impede the ability to justify the RSG [replacement steam generator] design" without the requirement for a license amendment. The Report also indicates that SCE's and MHI's decision to reject additional safety modifications contributed to the faulty steam generators and the shutdown of reactor Units 2 and 3.
This newly-obtained information concerns us greatly, and we urge the NRC to immediately conduct a thorough investigation into whether SCE and MHI did in fact fail to make needed safety enhancements to avoid the license amendment process.
All people in our nation, including the 8.7 million people who live within 50 miles of the San Onofre plant, must have confidence in the NRC's commitment to put safety before any other concern.
We believe this alarming Report raises serious concerns about SCE's and MHI's past actions. Safety, not regulatory short cuts, must be the driving factor in the design of nuclear facilities, as well as NRC's determination on whether Units 2 and 3 can be restarted.
We look forward to your prompt response detailing how public safety will be assured in light of this information. If you have any questions, please have your staff contact Dr. Michal Freedhoff of Rep. Markey's staff at 202-225-2836 or Grant Cope of Chairman Boxer's staff at 202-224-8832.
Barbara Boxer Edward J. Markey
Chairman Member of Congress
Senate Committee on Environment and Public Works