The utility that operates a shuttered California nuclear power plant where a radiation leak occurred last year knew about design problems with generators before they were installed, Sen. Barbara Boxer and Rep. Ed Markey said yesterday.
Boxer (D-Calif.), the Senate Environment and Public Works Committee's chairwoman, and Markey (D-Mass.), ranking member of the House Natural Resources Committee, sent a letter to Nuclear Regulatory Commission Chairwoman Allison Macfarlane, urging NRC to launch an investigation.
The lawmakers questioned whether plant operator Southern California Edison and equipment maker Mitsubishi Heavy Industries (MHI) kept information about the generators quiet to avoid an in-depth review by NRC. The utility did not apply for a license amendment before installing the replacement units in 2010 and 2011. That process would have triggered court-like hearings.
"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," the letter from Boxer and Markey said.
"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," it added.
San Onofre has been closed for a year, following a January 2012 radiation leak inside the Unit 3 steam generator at the San Diego County facility. SCE has asked NRC for approval to partly reopen the plant, which provided power to 1.4 million households (Greenwire, Oct. 4, 2012). The utility wants to restart Unit 2 and run it at 70 percent capacity for five months. It then would be shut down and inspected. An NRC decision on that could come as early as March (Greenwire, Dec. 19, 2012).
An NRC investigation last year found that Mitsubishi Heavy Industries, which manufactured the generators, used a faulty computer model to gauge steam and water flow. That triggered vibrations that caused extensive wear on the tubes (Greenwire, June 19, 2012).
NRC in a statement yesterday said that "we have received the letter from Sen. Boxer and Congressman Markey and will respond in the normal course of business. As an independent safety agency, we will review all available information in making a judgment as to whether the plant would meet our safety standards if restart were permitted."
Edison in a statement last night said that "it is fully cooperating with the NRC review process and is complying with all requests for information and documents related to the company's San Onofre Nuclear Generating Station. SCE leadership takes very seriously all allegations raised by the letter."
The information about the generators is contained in a 2012 Mitsubishi Heavy Industries (MHI) document, "Root Cause Analysis Report for tube wear identified in the Unit 2 and Unit 3 Steam Generators of San Onofre Generating Station." The document is proprietary and cannot be shared, congressional aides said.
A confidential source gave the document to Markey, an aide said. The Massachusetts congressman is a longtime critic of nuclear power.
"Both Mitsubishi and Southern California Edison knew about the potential problems with the steam generator design and chose to ignore the suggestions of their technical design team in order to avoid regulatory scrutiny," Markey said in an email. "This wasn't just a reactor break-down -- it was also a regulatory break-down.
"The Nuclear Regulatory Commission, which has had this document since last fall, should utilize all the regulatory tools it has to ensure that San Onofre stays shut down until these problems are fully understood and fully remedied," Markey added.
Environmental groups including Friends of the Earth have charged that SCE should have gone through a license amendment before installing the new generators because there were extensive changes from the earlier model. SCE instead went through a process known as replacement steam generator or RSG.
The report obtained by the lawmakers 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 and MHI's decision to reject additional safety modifications contributed to the faulty steam generators and the shutdown of reactor Units 2 and 3.
Boxer and Markey in their letter to NRC said that the "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."
Friends of the Earth called the revelation a "game changer."
"We knew Edison attempted to avoid the license amendment process back in the mid-2000s, but we didn't know that it would go so far as to refuse needed safety changes to the flawed design in order to do so," said Kendra Ulrich, nuclear campaigner for Friends of the Earth. "This amounts to the willful endangerment of the lives and livelihoods of millions of people in Southern California. Given the massive safety and corporate malfeasance implications, we are calling for the immediate release of this document in its entirety."