ML12187A154
| ML12187A154 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/10/2012 |
| From: | Doug Broaddus Plant Licensing Branch II |
| To: | Beach M - No Known Affiliation |
| Hall J | |
| Shared Package | |
| ML12187A133 | List: |
| References | |
| EDATS: SECY-2012-0298, G20120406, LTR-12-0255, TAC ME8868, TAC ME8869, SECY-2012-0298 | |
| Download: ML12187A154 (3) | |
Text
July 10, 2012 Ms. Miranda Beach 1160 San Dieguito Drive Encinitas, CA 92024
Dear Ms. Beach:
On behalf of the U.S. Nuclear Regulatory Commission (NRC), I am responding to your letter to Chairman Gregory B. Jaczko, dated May 13, 2012, in which you conveyed concerns about the safety of the San Onofre Nuclear Generating Station (SONGS).
As you noted in your letter, SONGS Units 2 and 3, are currently shut down due to excessive steam generator tube wear. On March 15, 2012, the NRC sent an augmented inspection team (AIT) to the site in response to the January 31, 2012, steam generator tube leak in Unit 3 and the subsequent discovery of significant tube-to-tube wear on both of the Unit 3 steam generators and significantly less tube-to-tube wear on one of the two Unit 2 steam generators.
For several months, this team of NRC inspectors, with assistance from other NRC experts, has been closely following the licensees actions to evaluate the causes of the excessive tube wear and to develop corrective actions to prevent further tube degradation. On June 18, 2012, NRC personnel met with representatives of Southern California Edison (SCE) in San Juan Capistrano, California, to present the NRCs issues and observations resulting from the AIT inspection. As discussed in that meeting, the NRC understands the steam generator thermal hydraulic conditions that resulted in the tube degradation; that the thermal hydraulic conditions in the steam generators were not accurately predicted during design; and that the licensee is evaluating and developing additional actions to fix and prevent any additional tube-to-tube degradation due to excessive vibration.
On March 27, 2012, the NRC issued a Confirmatory Action Letter (CAL) to SCE, identifying the specific actions the licensee has committed to take prior to returning the units to power operation. The CAL can be viewed on the NRC Web site, http://www.nrc.gov, in the Agencywide Documents Access and Management System (ADAMS), at Accession No. ML12087A323. Under the terms of the CAL, each unit will remain shut down until the licensee provides its written evaluations and responses to all of the CAL items for that unit. The NRC will perform additional related inspections and reviews of that information. Part of the information that the NRC staff will review will be the corrective actions taken by the licensee, including the plugging of additional steam generator tubes. The current safety analysis for the steam generators indicates that it is acceptable to operate with up to 8 percent (over 700) of the tubes plugged in each steam generator. If the licensee wishes to operate beyond this level of tube plugging, additional analyses would need to be performed by the licensee and these analyses would be subject to inspection or review by the NRC. In evaluating SCEs response to the CAL, the NRC will consider the effects of tube plugging on the ability of the steam generators to perform their safety function under a wide range of postulated accidents, including seismic events.
The NRC will not grant permission for restart until the agency is confident that the plant can be operated without undue risk to public health and safety, or the environment. The NRC will take as much time as needed in determining the appropriate actions to ensure the safety of the public, and will communicate its determinations to SCE regarding the restart of SONGS, Units 2 and 3, in writing.
You also expressed concern about whether SONGS would be able to handle a Fukushima-type event. Specifically, you were concerned about the plants response to a significant earthquake.
As part of the lessons learned from the Fukushima Dai-ichi event, the NRC recently issued a formal request for information to all operating reactor licensees to (1) reevaluate seismic and flooding hazards (including tsunami hazards) at their sites using applicable current methods and information, (2) conduct walkdowns of their facilities to ensure protection against the hazards in their current design basis, and (3) reevaluate their emergency communications systems and staffing levels. The NRC will evaluate the responses to the request for information in determining the need for plant modifications or further enhancements to address seismic and flooding hazards as well as emergency communications. You may find these orders and requests for information, as well as other information on the agencys response to the Fukushima event, at http://www.nrc.gov/reactors/operating/ops-experience/japan-info.html.
Thank you for conveying your concerns about these matters.
Sincerely,
/RA/
Douglas A. Broaddus, Chief San Onofre Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361 and 50-362
Pkg:ML12187A133; Incoming ML12164A196; Response ML12187A154 *via e-mail OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/PM NRR/LPL2-2/BC NAME LKGibson JBurkhardt JRHall DBroaddus DATE 7/5/12 7/5/12 7/5/12 7/10/12