ML13113A256

Request for Additional Information No. 73 Regarding Response to Confirmatory Action Letter

ML13113A256
Person / Time
Site:	San Onofre
Issue date:	05/10/2013
From:	Hall J Division of Operating Reactor Licensing
To:	Peter Dietrich Southern California Edison Co
Hall J
References
TAC ME9727
Download: ML13113A256 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 10,2013 Mr. Peter 1. Dietrich Senior Vice President and 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, UNIT 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING RESPONSE TO CONFIRMATORY ACTION LETTER (TAC NO. ME9727)

Dear Mr. Dietrich:

On March 27,2012 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML12087A323), the U.S. Nuclear Regulatory Commission (NRC) issued a Confirmatory Action Letter (CAL) to Southern California Edison (SCE, the licensee) regarding the San Onofre Nuclear Generating Station (SONGS), Units 2 and 3. The CAL confirms certain actions that SCE will take to address steam generator tube degradation issues at both units.

The CAL also confirms that SCE will not resume power operation at either unit until the NRC completes its review of those actions and formally communicates its permission to restart in written correspondence. SCE submitted its response to the CAL for SONGS, Unit 2 by letter dated October 3,2012 (ADAMS Accession No. ML12285A263).

The NRC staff is continuing its detailed review of SCE's CAL response for SONGS, Unit 2. The staff previously transmitted requests for additional information (RAls) containing 72 questions in letters to SCE dated December 26,2012, and March 18,2013, and in an electronic mail message dated March 15, 2013 (ADAMS Accession Nos. ML12361A065, ML13072A054, and ML13074A687, respectively). SCE provided responses to all 72 questions in multiple letters submitted to the NRC from January through April 2013, and the staff is reviewing those responses.

The NRC staff has determined that additional information is needed in order for the staff to complete its review and an additional question, RAJ 73, is enclosed with this letter. RAI 73 is a follow-up question based on the staffs review of SCE's response provided in a letter dated April 2, 2013, entitled "Response to Request for Additional Information (RAI 13), Revision 1,"

(ADAMS Accession No. ML13094A080, redacted version).

The enclosed RAI was discussed with your staff during the week of April 29, 2013. In order to complete our review, we request that you respond to the enclosed RAI by May 24. 2013.

P. Dietrich -2 If you are unable to respond to the RAI by the requested date, or if you have any further questions regarding this letter, please contact me at (301) 415-4032 or via e-mail at randy.hall@nrc.gov.

Sincerely, hV1ti£~A. 71J) des R. Hall, Senior Project Manager SONGS Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-361

Enclosure:

RAI73 cc w/Encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION ON SOUTHERN CALIFORNIA EDISON'S RESPONSE TO MARCH 27,2012, NRC CONFIRMATORY ACTION LETTER SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. 50-361 TAC NO. ME9727 By letter dated October 3, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML122850320), Southern California Edison (SCE, the licensee) submitted its response to the U.S. Nuclear Regulatory Commission (NRC) Confirmatory Action Letter (CAL) dated March 27,2012, for San Onofre Nuclear Generating Station (SONGS),

Unit 2.

The NRC staff is continuing its detailed review of SCE's CAL response for SONGS, Unit 2, and has determined that additional information is needed in order to complete our evaluation. The staff previously transmitted requests for additional information (RAls) containing 72 questions in letters to SCE dated December 26,2012, and March 18,2013, and in an electronic mail message dated March 15, 2013 (ADAMS Accession Nos. ML12361A065, ML13072A054, and ML13074A687, respectively). SCE provided responses to all 72 questions in multiple letters submitted to the NRC from January through April 2013, and the staff is reviewing those responses. In reviewing one of those responses, SCE's letter dated April 2, 2013, entitled "Response to Request for Additional Information (RAI 13), Revision 1," the staff identified the follow-up question provided below. For continuity, the numbering scheme for this additional question begins where the NRC's previous RAI questions regarding its review of the CAL response for Unit 2 ended.

RAI 73: Effects of Steam Generator Differences on the SBLOCA AOR In Section 4.2, "Impact of the RSGs on the SBLOCA AOR," of Reference 1, SCE assesses the effects of differences between the original and replacement steam generators on the small break loss of coolant accident (SBLOCA) analysis of record (AOR). Specifically, items (ii) through (vi) of Section 4.2 address the differences in tube geometry and material, primary and secondary side liquid inventory, elevation of components, and total metal mass, and provide the licensee's conclusions on the effects of each difference on the SBLOCA analysis, if any. The NRC staff reviewed available documentation for the S2M evaluation model (Reference 2) and did not identify a basis for these conclusions. Please provide the basis for these conclusions. If the basis is completely described by the RAI response, please qualify the conclusions with supplemental information.

- 2 REFERENCES

1. Letter from Richard J. St. Onge, SCE, to Document Control Desk, USNRC, "Docket No. 50-361, Response to Request for Additional Information (RAI 13), Revision 1, Regarding Confirmatory Action Letter Response (TAC No. ME9727), San Onofre Nuclear Generating Station, Unit 2," April 2, 2013; (ADAMS Accession No. ML13094A358, proprietary). [A non-proprietary version of this response is at ADAMS Accession No. NIL13094A080].

2. CENPD-137, Supplement 2-P-A, "Calculative Methods for the ABB CE Small Break LOCA Evaluation Model [S2M]," April 1998.

P. Dietrich -2 If you are unable to respond to the RAI by the requested date, or if you have any further questions regarding this letter, please contact me at (301) 415-4032 or via e-mail at randy.hall@nrc.gov.

Sincerely, IRAJ James R. Hall, Senior Project Manager SONGS Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-361

Enclosure:

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