ML12097A306
| ML12097A306 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 04/11/2012 |
| From: | Lyon C F Watts Bar Special Projects Branch |
| To: | |
| Lyon, Fred | |
| Shared Package | |
| ML12097A293 | List: |
| References | |
| TAC ME8200 | |
| Download: ML12097A306 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 11, 2012 LICENSEE: Tennessee Valley Authority FACILITY: Watts Bar Nuclear Plant, Unit 1 SUBJECT: SUMMARY OF MARCH 29,2012, PRE-APPLICATION MEETING WITH TENNESSEE VALLEY AUTHORITY ON CHANGING THE LICENSING BASIS FOR HYDROLOGIC ENGINEERING (TAC NO. ME8200) On March 29, 2012, a Category 1 public meeting was held between the U.S. Nuclear Regulatory Commission (NRC) and representatives of the Tennessee Valley Authority (TVA) at NRC Headquarters, One White Flint North, 11555 Rockville Pike, Rockville, Maryland. The purpose of the meeting was to discuss TVA's planned submittal of a license amendment request to revise the licensing and design basis for hydrologic engineering as described in the Watts Bar Nuclear Plant (WBN), Unit 1 Updated Final Safety Analysis Report (UFSAR). A list of attendees is enclosed. The licensee presented information on the background and content of the proposed request (see Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12097A312, public version). The licensee described its proposed technical changes to UFSAR Section 2.4, "Hydrologic Engineering," and other subsections. The original probable maximum flood (PMF) level at WBN was 738.1 feet, as reviewed and approved by the NRC in the UFSAR. In 1998, based on a revised flood analysis following several changes to dams upstream of WBN and changes to the assumptions about which dams would fail in certain events, TVA used the process in Title 10 of the Code of Federal Regulations, Section 50.59 to lower the PMF level in the UFSAR to 734.9 feet. The net effect of the revision was to lower predicted flood levels at WBN for all postulated flood and combination seismic/flood events. Based on a revised flood analysis in 2009, which used updated historical flood information and hydrologic models, TVA now proposes to revise the hydrologic engineering design basis, including the PMF level, which would also conform the WBN Unit 1 design basis to the design basis proposed for WBN Unit 2 in FSAR Amendment 108. The proposed new PMF level is 738.8 feet. The licensee stated that the proposed revision was also based on changes in river operations that were made in 2004. The changes had not been fully evaluated at that time, so the effect on PMF level was not recognized until the 2009 revised flood analysis. TVA also noted (1) that it had not yet completed analysis of recently identified potential Watts Bar reservoir overflow areas that could raise the new PMF level an additional 0.2 feet, (2) potential impacts from Order EA-12-049 related to Fukushima-Dai-ichi, and (3) potential impacts from any Chickamauga lock modifications, which were not included in the revised analysis since they are not funded up to 2016.
-The NRC staff queried TVA about several aspects of the proposed changes and recommended that TVA consider addressing the following issues in its submittal: The chronology and basis for the changes made to the hydrologic engineering design basis from 1995 to 1998 to 2009. An update of the status of TVA's resolution of long-term hydrology issues, per the staffs request in the NRC letter dated January 25, 2012. The relationship and use of the 25-year flood level versus the May 2003 flood level in TVA's new analysis. The justification for the proposed combinations of dam failure scenarios used in TVA's new analysis. The purpose of the finite element analysis on the Fontana Dam. Discuss whether approvals for the dam and river operations modifications are required from other agencies (e.g., U.S. Army Corps of Engineers). Discuss the overall uncertainties in TVA's revised analysis calculations. Justification for the use of any compensatory measures as a result of TVA's revised analysis. Discuss the temporary modification to the thermal barrier booster pump flood barrier protection in the UFSAR. 10. Discuss any impact on TVA's individual plant examination of external events or final environmental impact statement due to the revised flood analysis. 11. Discuss whether any flood barriers at the plant are impacted by the revised PMF level. 12. Discuss the use and control of sand baskets (e.g., at the WBN recreational area). 13. Discuss the impact on any safety-related equipment other than the thermal barrier booster pumps. 14. Discuss the impact of TVA's five proposed combinations of dam failure scenarios within its revised flood analysis. TVA acknowledged the NRC staff's questions and comments and stated that they would be considered as the licensee continues to prepare its submittal. No regulatory decisions were made at the meeting. A member of the public was in attendance by telephone. Public Meeting Feedback forms were not received.
-Please direct any inquiries to me at 301-415-2296, or Carl F. Lyon, Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. List of cc w/encl: Distribution via LIST OF MARCH 29,2012, PRE-APPLICATION MEETING WITH TENNESSEE VALLEY ON CHANGING THE LICENSING BASIS FOR HYDROLOGIC ENGINEERING WATTS BAR NUCLEAR PLANT. UNIT G. Arent J.Shea G. Watkins R. Cole P. Gaillard P. Selman* T. Morgan* L. Raghavan P. Milano S. Campbell J. Poole M. Murphy J. Gwo* S.Lingam S. Shaeffer* E. Brown R. Monk* R. Haag F. Lyon URS D. Klett* *by telephone Enclosure Please direct any inquiries to me at 301-415-2296, or Fred.Lyon@nrc.gov. IRA by Patrick Milano forI Carl F. Lyon, Project Manager Watts Bar Special Projects Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. List of cc w/encl: Distribution via DISTRIBUTION: PUBLIC RidsRgn2MailCenter Resource SShaeffer, RII LP-WB Branch Reading TWertz, NRR RHaag, RII RidsAcrsAcnw MailCTR Resource PMilano, NRR EBrown, NRR RidsNrrDorlLp:Wb Resource JPoole. NRR RMonk, RII RidsNrrPMWatts Bar1 Resource LRaghavan, NRR RidsNrrDeEmcb Resource RidsNrrLABClayton Resou rce JGwo, NRR MKotzalas, EDO Region 2 RidsOgcRp Resource SLingam, NRR ADAMS Accession No. PKG ML 12097A293. Meeting Notice ML 120750109, Meeting Summary ML Public Handouts ML12097OFFICE DORULPWB/PM DORULPWB/LA DORULPWB/BC DORULPWB/PM NAME FLyon BClayton SCamp bell (PMilano for) FLyon (PMilano for) DATE 04/11/12 04/11/12 04/11/12 04111112 OFFICIAL RECORD COPY