ML060260498

(Songs), Unit 3 - Evaluation of the Response to Generic Letter 2004-01, Requirements for Steam Generator Tube Inspections

ML060260498
Person / Time
Site:	San Onofre
Issue date:	01/18/2006
From:	Terao D Plant Licensing Branch III-2
To:	Rosenblum R Southern California Edison Co
Kalyanam N,NRR/DLPM,415-1480
References
GL-04-001, TAC MC4850
Download: ML060260498 (5)

Text

January 18, 2006 Mr. Richard M. Rosenblum Chief Nuclear Officer Southern California Edison Company San Onofre Nuclear Generating Station P.O. Box 128 San Clemente, CA 92674-0128

SUBJECT:

SAN ONOFRE NUCLEAR GENERATING STATION (SONGS), UNIT 3 -

EVALUATION OF THE RESPONSE TO GENERIC LETTER 2004-01, REQUIREMENTS FOR STEAM GENERATOR TUBE INSPECTIONS (TAC NO. MC4850)

Dear Mr. Rosenblum:

On August 30, 2004, the U.S. Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-01, Requirements for Steam Generator Tube Inspections. The purpose of GL 2004-01 was to obtain information that would enable the NRC staff to determine whether licensees steam generator tube inspection programs comply with the existing tube inspection requirements (the plant technical specifications in conjunction with Appendix B to Part 50 of Title 10 of the Code of Federal Regulations).

By letter dated October 26, 2004 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML043020250), as supplemented by letter dated November 23, 2005 (ADAMS Accession No. ML053320210), Southern California Edison (SCE), the licensee for SONGS, submitted the response to GL 2004-01.

The NRC Staff has reviewed the SCE response to GL 2004-01 for SONGS, Unit 3. As discussed in the enclosed evaluation, the NRC staff concluded that the licensees overall response to the GL is acceptable.

If you have any questions, please call the Project Manager, N. Kalyanam, at (301) 415-1480.

Sincerely,

/RA/

David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-362

Enclosure:

Staff Evaluation cc w/encl: See next page

ML053320210), Southern California Edison (SCE), the licensee for SONGS, submitted the response to GL 2004-01.

The NRC Staff has reviewed the SCE response to GL 2004-01 for SONGS, Unit 3. As discussed in the enclosed evaluation, the NRC staff concluded that the licensees overall response to the GL is acceptable.

If you have any questions, please call the Project Manager, N. Kalyanam, at (301) 415-1480.

Sincerely,

/RA/

David Terao, Chief Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-362

Enclosure:

Staff Evaluation cc w/encl: See next page DISTRIBUTION PUBLIC LPLIV r/f RidsNrrDorl (CHaney/CHolden)

RidsNrrDorlLplg (DTerao) RidsNrrPMNKalyanam RidsNrrLALFeizollahi AHiser RidsAcrsAcnwMailCenter RidsOgcRp RidsRgn4MailCenter (TPruett) RidsNrrDorlDpr PKlein MYoder ACCESSION NO: ML060260498 OFFICE NRR/LPL4/PM NRR/LPL4/LA NRR/LPL4/BC NAME NKalyanam LFeizollahi DTerao DATE 1/12/06 1/12/06 1/18/06 EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RESPONSE TO NRC GENERIC LETTER 2004-01 SOUTHERN CALIFORNIA EDISON SAN ONOFRE NUCLEAR GENERATING STATION, UNIT NO. 3 DOCKET NO. 50-362 On August 30, 2004, the Nuclear Regulatory Commission (NRC) issued Generic Letter (GL) 2004-01, "Requirements for Steam Generator Tube Inspections." The purpose of GL 2004-01 was to obtain information that would enable the NRC staff to determine whether licensees steam generator (SG) tube inspection programs comply with the existing tube inspection requirements the plant Technical Specifications (TSs) in conjunction with Appendix B of Title 10 of the Code of Federal Regulations (10 CFR) Part 50.

Licensees who concluded that their SG tube inspections have not been or are not being performed consistent with the NRCs position on the requirements in the TSs, in conjunction with Appendix B of 10 CFR Part 50, were requested to submit a safety assessment. As part of the safety assessment, licensees were to address whether their safety bases for limiting inspections within the tubesheet constitutes a change to the "method of evaluation" for establishing the structural and leakage integrity of the tube-to-tubesheet joint. The NRC staff requested this information since it was expected that licensees safety bases relied on a mechanical expansion joint rather than the tube-to-tubesheet weld. Since the original tube-to-tubesheet joint was most likely designed by demonstrating that the stresses in the tube, weld, and tubesheet satisfy the allowable stress values in Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), or other similar standard, the NRC staff questioned whether the safety basis for limiting inspections relied on demonstrating that the expansion joint satisfied some criteria (e.g., minimum tube pullout load criteria, allowable leakage) beyond those specified in Section III of the ASME Code.

By letter dated October 26, 2004 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML043020250), as supplemented by letter dated November 23, 2005 (ADAMS Accession No. ML053320210), Southern California Edison, the licensee for San Onofre Nuclear Generating Station (SONGS), Unit 3, submitted a response to GL 2004-01. In the response, you concluded that the safety basis used to support the tube inspection practices does not constitute a change to the method of evaluation. This conclusion appears to be based, in part, on an assumption that the GL was implying that the selection of non-destructive evaluation techniques define the limits of the reactor coolant pressure boundary. The GL's discussion of the original design basis, however, was related to the "safety analysis" performed by certain licensees to support a conclusion that flaws located a certain distance below the top of the tubesheet do not have any safety implications. This safety basis relies on a mechanical interference fit between the tube and the tubesheet for establishing the ENCLOSURE

tube-to-tubesheet joint (i.e., forming the reactor coolant pressure boundary). However, for many plants (if not all), the original design of the steam generator gave no credit for this interference fit since the weld between the tube and the tubesheet ensured the integrity of the tube-to-tubesheet joint. In fact, the design rules (ASME Code,Section III) do not address the use of an interference fit for maintaining pressure boundary integrity. As a result, the NRC staff questioned whether licensees were using a different method of evaluation for assessing the adequacy of the tube-to-tubesheet joint.

Although your response to the "method of evaluation" item did not focus on the NRC staff's area of concern, we conclude that your overall response to the GL is acceptable. You indicated that your tube inspection practices at SONGS, Unit 3, are not consistent with the NRC staff position, and that this has been entered into your corrective action program. You further indicated that you plan on submitting a license amendment to clarify your steam generator tube inspection practices in the tubesheet region. This license amendment request was submitted on November 3, 2005, and is currently being reviewed by the NRC staff. In the event that a different method of evaluation for the tube-to-tubesheet joint is in use at SONGS, Unit 3, it will be reviewed as part of the license amendment process.

Principal Reviewers: P. Klein M. Yoder Date: January 18, 2006

San Onofre Nuclear Generating Station Units 2 and 3 cc:

Mr. Daniel P. Breig Resident Inspector/San Onofre NPS Southern California Edison Company c/o U.S. Nuclear Regulatory Commission San Onofre Nuclear Generating Station Post Office Box 4329 P. O. Box 128 San Clemente, CA 92674 San Clemente, CA 92674-0128 Mayor Mr. Douglas K. Porter, Esquire City of San Clemente Southern California Edison Company 100 Avenida Presidio 2244 Walnut Grove Avenue San Clemente, CA 92672 Rosemead, CA 91770 Mr. James T. Reilly Mr. David Spath, Chief Southern California Edison Company Division of Drinking Water and San Onofre Nuclear Generating Station Environmental Management P.O. Box 128 P. O. Box 942732 San Clemente, CA 92674-0128 Sacramento, CA 94234-7320 Mr. James D. Boyd, Commissioner Chairman, Board of Supervisors California Energy Commission County of San Diego 1516 Ninth Street (MS 31) 1600 Pacific Highway, Room 335 Sacramento, CA 95814 San Diego, CA 92101 Mr. Ray Waldo, Vice President Eileen M. Teichert, Esq. Southern California Edison Company Supervising Deputy City Attorney San Onofre Nuclear Generating Station City of Riverside P.O. Box 128 3900 Main Street San Clemente, CA 92764-0128 Riverside, CA 92522 Mr. Brian Katz Mr. Gary L. Nolff Southern California Edison Company Power Projects/Contracts Manager San Onofre Nuclear Generating Station Riverside Public Utilities P.O. Box 128 2911 Adams Street San Clemente, CA 92764-0128 Riverside, CA 92504 Mr. Steve Hsu Regional Administrator, Region IV Department of Health Services U.S. Nuclear Regulatory Commission Radiologic Health Branch 611 Ryan Plaza Drive, Suite 400 MS 7610, P.O. Box 997414 Arlington, TX 76011-8064 Sacramento, CA 95899 Mr. Michael Olson Mr. A. Edward Scherer San Diego Gas & Electric Company Southern California Edison Company P.O. Box 1831 San Onofre Nuclear Generating Station San Diego, CA 92112-4150 P.O. Box 128 San Clemente, CA 92674-0128 Mr. Ed Bailey, Chief Radiologic Health Branch State Department of Health Services Post Office Box 997414 (MS7610)

Sacramento, CA 95899-7414 November 2005