ML12311A438

Requests for Additional Information for the Review of the South Texas Project, Units 1 and 2, License Renewal Application - Set 25 (TAC Nos. ME4936 and ME4937)

ML12311A438
Person / Time
Site:	South Texas, 05000599
Issue date:	11/19/2012
From:	Daily J W License Renewal Projects Branch 1
To:	Rencurrel D W South Texas
Daily J W, 415-3873
References
TAC ME4936, TAC ME4937
Download: ML12311A438 (6)

Text

UNITED NUCLEAR REGULATORY WASHINGTON, D.C.

November 19, 2012 Mr. D. W. Rencurrel Chief Nuclear Officer STP Nuclear Operating Company P.O. Box 289 Wadsworth,TX 77483 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION

-SET 25 (TAC NOS. ME4936 AND ME4937)

Dear Mr. Rencurrel:

By letter dated October 25, 2010, STP Nuclear Operating Company (STPNOC or the applicant) submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54, to renew operating licenses NPF-76 and NPF-80 for South Texas Project, Units 1 and 2, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review. These requests for additional information were discussed with Arden Aldridge, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me by telephone at 301-415-3873 or bye-mail at john.daily@nrc.gov.

Sincerely, John W. Daily, Sr. Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-498 and Requests for additional cc w/encl:

SOUTH TEXAS PROJECT, UNITS 1 AND REQUEST FOR ADDITIONAL INFORMATION, SET (T AC NOS. ME4936 AND RAI Follow-up on Operating Experience Implementation (3.0.5) Background By letter dated June 14,2012, STP Nuclear Operating Company (STPNOC or the applicant) revised license renewal application (LRA) Section A 1, which is part of the updated final safety analysis report (UFSAR) supplement, to provide a more detailed description of how operating experience will be reviewed on an ongoing basis to address operating experience concerning related degradation and aging management during the terms of the renewed licenses.

This summary description identifies several enhancements that will be made to the existing Operating Experience Program and the Corrective Action Program. LRA Section A4 describes the license renewal commitments and is also part of the UFSAR supplement.

Commitment No. 41, as revised by letter dated June 14, 2012, addresses the enhancements that will be made to the Operating Experience Program and the Corrective Action Program and states that they will be implemented by December 31, 2014. LRA Section A 1 describes the same enhancements but does not state an explicit implementation schedule.

Therefore, the staff is unclear with respect to the applicant's intended implementation schedule.

In addition, the staffs position, as described in Final License Renewal Interim Staff Guidance, LR-ISG-2011-05, "Ongoing Review of Operating Experience," is that any enhancements to the existing operating experience review activities should be put in place no later than the date the renewed operating licenses are issued and implemented on an ongoing basis throughout the terms of the renewed licenses.

The December 31,2014, implementation schedule could be after issuance of the renewed operating licenses.

As such, it is not clear how operating experience on age-related degradation and aging management will be considered during the terms of the renewed operating licenses prior to full implementation of the enhancements.

Request Clarify the UFSAR supplement regarding the implementation schedule for the enhancements that will be made to the Operating Experience Program and the Corrective Action Program. If implementation will be after issuance of the renewed operating licenses, provide a justification and include any relevant practical considerations that would impact the implementation timeframe.

RAI 4.3.2.11-6 Follow-up on STPNOC CASS LBB Analysis (060A) Background The staff notes that the applicant's current position on the leak-before-break (LBB) evaluation of cast austenitic stainless steel (CASS) piping is that it is not a time-limited aging analysis (TLAA) for STP. Regarding the fracture mechanics calculation in the LBB evaluation of CASS piping, the applicant's response to Part 2 of the request for additional information, (RAI) 4.3.2.11-2 states, in part: Although the fracture mechanics calculation considers aging of the material property, aging is not based on the plant life. Aging is based on the minimum material properties possible and the value used by the calculation will be the same whether the plant life is 40 years, 60 years, or 100 years. Therefore, fracture mechanics calculation is not a TLAA in accordance with 10 CFR 54.3(a) Criterion

3. The response to Part 3 of RAI 4.3.2.11-2 cites a technical report from 1983 Westinghouse Report WCAP-1046, "The Effects of Thermal Aging on the Structural Integrity of Cast Stainless Steel Piping for Westinghouse Nuclear Steam Supply Systems" as the basis for the saturated fracture toughness assumed in the analyses.

Considerable information has been developed since 1983 to provide improved understanding of thermal embrittlement of CASS materials by O. Chopra of Argonne National Laboratory, C. Faidyof Electricite de France, and others. See, for example NUREG/CR-4513, Rev. 1 (1994), "Estimation of Fracture Toughness of Cast Stainless Steels During Thermal Aging in LWR Systems";

Appendix A of draft EPRI report 1024966, "Probabilistic Reliability Model for Thermally Aged Cast Austenitic Stainless Steel Piping"; and ASME paper PVP201 0-25085, "Flaw Evaluation in Elbows Through French RSEM Code" by C. Faidy. Although the RAI response states that the material property aging is based on the "minimum material properties possible," the RAI response does not provide justification to support that statement in light of additional information on thermal aging of CASS over the last 29 years, and, in particular, does not demonstrate that the aging after 60 years of operation is bounded by the thermal embrittlement saturation values assumed in the existing analysis.

Request Provide justification that the assumed saturated fracture toughness in the CASS LBB evaluations bounds the expected toughness at 60 years of operation, considering the information sources cited above and others as necessary. Specify the information sources used in response to request (1). Given the response to request (1), identify whether STPNOC will retain its current disposition of the LBB evaluation of CASS piping, or will instead treat it as: (a) a TLAA evaluated under 10 CFR 54.21 {c){1 )(i) (Le., the analysis "remains valid for the period of extended operation");

or (b) a TLAA evaluated under 10 CFR 54.21{c)(1)(ii) (Le., the analysis "has been projected to the

-end of the period of extended operation");

or (c) other determination (please describe in full). Provide the justification for your disposition of the thermal aging aspect of the LBB evaluation for CASS material.

RAI B2.1.9-3d (021) Background RAI B2.1.9-3 and several follow-up RAls have addressed aging management issues associated with coating degradation in the essential cooling water system. In the RAI response dated August 21, 2012, STP provided a comprehensive approach toward addressing this issue. The response states that the current inspection interval of 5 years is being increased to 6 years based on industry and STP operating experience, and that this interval aligns with vendor inspection guidance for in-service coatings and with the 6-year major equipment outage and inspection interval.

The response also listed a new component type of "coatings," a new intended function of "maintain coating integrity," and a new aging effect requiring management of "loss of coating integrity." Further understanding of the operating experience cited in the previous response is needed to validate the bases for increasing the inspection interval from 5 years to 6 years. NRC resident inspectors noted that, for most of the heat exchanger coating inspections they have witnessed, the coatings required at least some "touch-up," with the "turnaround" areas requiring more repair than other areas. In addition, the scope of STP's operating experience reviews is not clear, given that the RAI response dated March 29,2012, states that procedures need to be enhanced to require that protective coating failures be documented in the corrective action program. The staff noted that the new "maintain coating integrity" intended function was not integrated into LRA Table 2.1-1, "Intended Functions:

Abbreviation and Definitions." Request Provide a summary of the inspection results and repair efforts associated with the five sets of components (Le., water boxes, coolers, and piping) discussed in RAI response dated August 21,2012. Provide the approximate amount of missing coating material, including the number of locations requiring repair, and the range of repair sizes. Confirm that the operating experience reviews included inspection results and repair efforts beyond those captured in the corrective action program. Ensure that the appropriate tables in the LRA have been updated to reflect the creation of a new intended function of a new component type with a new aging effect requiring management.

November 19, 2012 Mr. D. W. Rencurrel Chief Nuclear Officer STP Nuclear Operating Company P.O. Box 289 Wadsworth,TX 77483 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION

-SET 25 (TAC NOS. ME4936 AND ME4937)

Dear Mr. Rencurrel:

By letter dated October 25, 2010, STP Nuclear Operating Company (STPNOC or the applicant) submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54, to renew operating licenses NPF-76 and NPF-80 for South Texas Project, Units 1 and 2, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review. These requests for additional information were discussed with Arden Aldridge, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me by telephone at 301-415-3873 or bye-mail at john.daily@nrc.gov.

Sincerely, IRA! John W. Daily, Sr. Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-498 and Requests for additional cc w/encl: Listserv DISTRIBUTION:

See next page ADAMS Accession No. ML

• concurrence via email OFFICE PM: DLRlRPB1 LA: DLR/RPB2 BC: DLRlRPB1 PM: DLRlRPB1 NAME JDaily IKing* DMorey JDaily DATE 11/19/12 11/8112 11/19/12 11119112 OFFICIAL RECORD COpy Letter to D. W. Rencurrel from John W. Daily dated November 19, 2012 REQUESTS FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE SOUTH TEXAS PROJECT, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION

-SET 25 (TAC NOS. ME4936 AND ME4937) DISTRIBUTION:

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