ML12201B519

Supplemental Request for Additional Information for the Review of the Davis-Besse Nuclear Power Station License Renewal Application Related to Pressure Temperature Limits

ML12201B519
Person / Time
Site:	Davis Besse
Issue date:	07/26/2012
From:	Harris B License Renewal Projects Branch 1
To:	Allen B FirstEnergy Nuclear Operating Co
Harris B 301-415-2277
References
TAC ME4640
Download: ML12201B519 (5)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 26, 2012 Mr. Barry S. Allen, Vice President Davis-Besse Nuclear Power Station FirstEnergy Nuclear Operating Company 5501 North State Route 2 Oak Harbor, OH 43449

SUBJECT:

SUPPLEMENTAL REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE DAVIS-BESSE NUCLEAR POWER STATION LICENSE RENEWAL APPLICATION RELATED TO PRESSURE-TEMPERATURE LIMITS (TAC NO. ME4640)

Dear Mr. Allen:

By letter dated August 27,2010, FirstEnergy Nuclear Operating Company submitted an application pursuant to Title 10 of the Code of Federal Regulations, Part 54 for renewal of Operating License NPF-3 for the Davis-Besse Nuclear Power Station. The staff of the U.S. Nuclear Regulatory Commission (NRC or the staff) is reviewing this application in accordance with the guidance in NUREG-1800, "Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants." During its review, the staff has identified areas where additional information is needed to complete the review. The staff's requests for additional information are included in the enclosure. Further requests for additional information may be issued in the future.

Items in the enclosure were discussed with Steven Dort, of your staff, 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 301-415-2277 or bye-mail at brian.harris2@nrc.gov.

Sincerely, Brian K. Harris, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket No. 50-346

Enclosure:

As stated cc w/encl: Listserv

DAVIS-BESSE NUCLEAR POWER STATION LICENSE RENEWAL APPLICATION SUPPLEMENTAL REQUEST FOR ADDITIONAL INFORMATION RELATED TO PRESSURE-TEMPERATURE LIMITS RAI 4.2.2 Pressure-Temperature (P-T) Limits

Background:

The Davis-Besse License Renewal Application (LRA), Section 4.2.4 describes the time-limited aging analysis for the pressure-temperature (P-T) limit curves at Davis-Besse. As stated in LRA Section 4.2.4, the Davis-Besse P-T limit curves are established in a P-T Limits Report (PTLR),

the contents of which are controlled in accordance with Technical Specification (TS) 5.6.4 requirements. The current Davis-Besse PTLR contains P-T limit curves that are valid through 32 effective full power years of facility operation. LRA Section 4.2.4 states that the P-T limit curves, as established in the PTLR, will be updated as necessary in accordance with TS 5.6.4 requirements and managed for the period of extended operation, as part of the Reactor Vessel Surveillance Program (LRA Appendix B, Section B.2.35), in accordance with the requirements of Title 10 of the Code of Federal Regulations (10 CFR) 54.21 (c)(1 )(iii).

10 CFR Part 50, Appendix G, Paragraph IV.A states that, "the pressure-retaining components of the reactor coolant pressure boundary [RCPB] that are made of ferrific materials must meet the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code [ASME Code, Section III], supplemented by the additional requirements set forth in

[paragraph IV.A.2, "Pressure-Temperature (P-T) Limits and Minimum Temperature Requirements"]... " Therefore, 10 CFR Part 50, Appendix G requires that P-T limits be developed for the ferritic materials in the reactor vessel (RV) beltline (neutron fluence O'!: 1 x 1017 nfcm2, E> 1 MeV), as well as ferritic materials not in the RV beltline (neutron fluence < 1 x 1017 n/cm2, E > 1 MeV). Further, 10 CFR Part 50, Appendix G requires that all RCPB components must meet the American Society of Mechanical Engineers (ASME) Code,Section III requirements. The relevant ASME Code,Section III requirement that will affect the P-T limits is the lowest service temperature requirement for all RCPB components specified in Section III, NB-2332(b).

P-T limit calculations for ferritic RCPB components that are not RV beltline shell materials may define P-T curves that are more limiting than those calculated for the RV beltline shell materials.

This may be due to the following factors:

1. RV nozzles, penetrations, and other discontinuities have complex geometries that may exhibit significantly higher stresses than those for the RV beltline shell region. These higher stresses can potentially result in more restrictive P-T limits, even if the reference temperature (RT NDT) for these components is not as high as that of RV beltline shell materials that have simpler geometries.

2. Ferritic RCPB components that are not part of the RV may have initial RTNDT values, which may define a more restrictive lowest operating temperature in the P-T limits than those for the RV beltline shell materials.

ENCLOSURE

- 2 Request:

Describe how the P-T limit curves to be developed for use in the period of extended operation, and the methodology used to develop these curves, consider all RV materials (beltline and non beltline) and the lowest service temperature of all ferritic RCPB materials, consistent with the requirements of 10 CFR Part 50, Appendix G.

Letter to Barry S. Allen from Brian K. Harris dated July 26,2012

SUBJECT:

SUPPLEMENTAL REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE DAVIS-BESSE NUCLEAR POWER STATION LICENSE RENEWAL APPLICATION RELATED TO PRESSURE-TEMPERATURE LIMITS (TAC NO. NlE4640 DISTRIBUTION:

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ML12201B519 OFFICE LA:DLR/RPB1 PM:DLR/RPB1 BC:DLR/RPB1 PM: DLR/RPB 1 NAME YEdmonds BHarris DMorey BHarris DATE 07/26/12 07/26/12 I 07/25/12 I

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