ML071620029
| ML071620029 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/21/2007 |
| From: | Hiltz T NRC/NRR/ADRO/DORL/LPLIV |
| To: | Mills G - No Known Affiliation |
| Kalyanam N, NRR/DORL/LP4, 415-1480 | |
| References | |
| TAC MD5573, TAC MD5574 | |
| Download: ML071620029 (4) | |
Text
June 21, 2007 Mr. Glen R. Mills P.O. Box 3393 Mission Viejo, CA 92690
SUBJECT:
RESPONSE TO YOUR LETTER DATED APRIL 24, 2007 - CONCERNS RELATING TO PRESSURIZER NOZZLES AND INTEGRITY OF THE REACTOR COOLANT PRESSURE BOUNDARY
Dear Mr. Mills:
By letter dated April 24, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML071380466), to the Office of the Inspector General (OIG) of the Nuclear Regulatory Commission (NRC), you described your concerns regarding the pressurizer surge line, safety and relief nozzles, and the integrity of the San Onofre Nuclear Generating Station, Units 2 and 3 (SONGS 2 and 3) reactor coolant pressure boundary (RCPB). You had suggested that SONGS Unit 2 should be shut down immediately and remain shut down until it meets the Material Reliability Program (MRP)-139 guidance and SONGS Unit 3 should be shut down immediately based on "unexpected defects" being identified within the initial weld overlay on the pressurizer surge line.
After reviewing the concerns raised in your letter and considering the most appropriate process to address your concerns, your letter was referred to the NRC Office of Nuclear Reactor Regulation (NRR), Division of Component Integrity (DCI). DCI reviewed your concerns and has concluded that current NRC requirements in conjunction with ongoing staff followup actions in response to reported instances of flaws in the RCPB will continue to ensure RCPB integrity during normal operation, transients, and accident events. The basis for this conclusion is discussed below.
The NRC has conducted discussions with the SONGS 2 and 3 licensee regarding the inspection and mitigation of Alloy 82/182 pressurizer butt welds, and issued a confirmatory action letter (CAL) to them on March 22, 2007. This CAL is available on the NRC public website (ADAMS Accession No. ML070800004). The CAL confirms the licensee's commitment that neither SONGS Unit 2 nor Unit 3 will operate past December 31, 2007, without mitigating the Alloy 82/182 Pressurizer butt welds by applying weld overlays. These actions will ensure that the SONGS units will continue to be in compliance with the MRP-139 guidance for pressurizer dissimilar metal welds.
Regarding the unexpected defect referred to in your letter, this flaw was encountered when the licensee applied a pre-emptive weld overlay on the SONGS Unit 3 pressurizer surge nozzle weld during the last refueling outage. The unexpected defect was associated with the first weld layer of the overlay. As a result, the first layer of the overlay was removed, along with the flaw, and the weld was restored to an acceptable condition.
G. Mills In addition, the licensee has informed NRC that it has inspected the pressurizer surge nozzle Alloy 82/182 welds at both Units 2 and 3 to the maximum extent possible using the state-of-the-art techniques and no indications or defects were identified during these inspections.
A response to your comments regarding leakage monitoring is contained in our letter to you from Michele G. Evans, Director, DCI, dated May 29, 2007 (ADAMS Accession No. ML071490099).
I hope that the information in this letter adequately responds to your concerns.
Sincerely,
/RA/
Thomas G. Hiltz, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361, 50-362 cc: See next page
I hope that the information in this letter adequately responds to your concerns.
Sincerely,
/RA/
Thomas G. Hiltz, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-361, 50-362 cc: See next page DISTRIBUTION:
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NRR/LPL4/BC NAME NKalyanam JBurkhardt TChan SRosenberg THiltz DATE 6/20/07 6/20/07 6/15/07 6/19/07 6/21/07
May 2007 San Onofre Nuclear Generating Station Units 2 and 3 cc:
Mr. Raymond W. Waldo, Vice President, Nuclear Generation Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 Mr. Douglas K. Porter, Esquire Southern California Edison Company 2244 Walnut Grove Avenue Rosemead, CA 91770 Dr. David Spath, Chief Division of Drinking Water and Environmental Management California Dept. of Health Services 850 Marina Parkway, Bldg P, 2nd Floor Richmond, CA 94804 Chairman, Board of Supervisors County of San Diego 1600 Pacific Highway, Room 335 San Diego, CA 92101 Mark L. Parsons Deputy City Attorney City of Riverside 3900 Main Street Riverside, CA 92522 Mr. Gary L. Nolff Assistant Director - Resources City of Riverside 3900 Main Street, 4th Floor Riverside, CA 92522 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 Mr. Michael J. DeMarco San Diego Gas & Electric Company 8315 Century Park Ct. CP21G San Diego, CA 92123-1548 Director, Radiologic Health Branch State Department of Health Services P.O. Box 997414, MS 7610 Sacramento, CA 95899-7414 Resident Inspector San Onofre Nuclear Generating Station c/o U.S. Nuclear Regulatory Commission Post Office Box 4329 San Clemente, CA 92674 Mayor City of San Clemente 100 Avenida Presidio San Clemente, CA 92672 Mr. James T. Reilly Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128 Mr. James D. Boyd, Commissioner California Energy Commission 1516 Ninth Street (MS 31)
Sacramento, CA 95814 Brian Katz Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92764-0128 Mr. Steve Hsu Department of Health Services Radiologic Health Branch MS 7610, P.O. Box 997414 Sacramento, CA 95899-7414 Mr. A. Edward Scherer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128