ML113140275
| ML113140275 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 11/17/2011 |
| From: | James Kim Plant Licensing Branch 1 |
| To: | Entergy Nuclear Operations |
| Kim J, NRR/DORL, 415-4125 | |
| References | |
| TAC ME6248 | |
| Download: ML113140275 (5) | |
Text
Official Use Only Proprietary Information UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 November 17,2011 Site Vice President Entergy Nuclear Operations, Inc.
Vermont Yankee Nuclear Power Station P.O. Box 250 Governor Hunt Road Vernon, VT 05354
SUBJECT:
VERMONT YANKEE NUCLEAR POWER STATION - REQUEST FOR ADDITIONAL INFORMATION REGARDING CORE PLATE HOLD DOWN BOLT INSPECTION PLAN AND ANALYSIS (TAC NO. IVIE6248)
Dear Sir or Madam:
By letter dated March 18, 2011 (Agencywide Document Access and Management System (ADAMS) Accession No. ML110840068), Entergy Nuclear Operations, Inc. (Entergy) submitted a plant-specific analysis report of the core plate hold down bolts. In Amendment 11 of the license renewal application (LRA), Entergy committed to either install core plate wedges or complete a plant-specific analysis to determine the acceptance criteria for continued inspection of the core plate hold down bolts in accordance with Boiling Water Reactor (BWR) Vessel and Internals Project (BWRVIP), BWR Core Plate Inspection and Flaw Evaluation Guidelines (BWRVIP-25) and submit the inspection plan and analysis to the Nuclear Regulatory Commission (NRC) 2 years prior to the period of extended operation (PEO). By letter dated December 30, 2010 (ADAMS Accession No. ML110040117), Entergy updated the commitment to indicate the inspection plan and analysis would be provided one year prior to the PEO.
The NRC staff reviewed the portions of the subject request related to the core plate hold down bolt analysis and has determined that additional information is needed to complete its review.
The specific questions are found in the enclosed request for additional information (RAI). A response to the RAI is requested by January 6, 2012.
Official Use Only Proprietary Information When Enclosure 2 is detached, this letter and Enclosure 1 are no longer proprietary_
Offisial Use Only Proprietary Information
-2 Please contact me at (301) 415-4125 if you have any questions on this issue.
Sincerely,
/raj James Kim, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-271
Enclosures:
- 1. RAI (non-proprietary)
- 2. RAI (proprietary) cc w/encl 1: Distribution via Listserv Offisial Use Only Proprietary Information When Enclosure 2 is detached, this letter and Enclosure 1 are no longer proprietary.
REQUEST FOR ADDITIONAL INFORMATION REGARDING CORE PLATE HOLD DOWN BOLT INSPECTION PLAN AND ANALYSIS ENTERGY NUCLEAR OPERATIONS, INC.
VERMONT YANKEE NUCLEAR POWER STATION DOCKET NO. 50-271
[proprietary]
[proprietary]
Section 6.0 Loads and Load combinations: General Electric Hitachi (GEH) safety communication (SC) 09-03 issued on August 3, 2009, addresses the acoustic load (AC) load acting on the shroud in a postulated recirculation suction line break event, and its omission from shroud loads may be non-conservative. The core plate is attached to the shroud, and the AC load may have an impact on the stress analysis of core plate bolts. It is noted that Boiling Water Reactor Vessel and Internals Project (BWRVIP)-25 Appendix-A calculation for core plate hold down bolt stress analysis does not address AC load because it was issued prior to SC 09-03.
The licensee is requested to either re-compute the faulted stress in core plate bolts or provide a justification for not considering the AC loading in the faulted load combination in Table 6-2.
Sections 6.6 and 8.1 Friction: Entergy takes credit for friction between the core plate rim and shroud ledge using a friction factor of 0.2 in Vermont Yankee Nuclear Power Station (VY) core plate bolt stress analysis while BWRVIP-25 Appendix-A core analysis does not take credit for friction. It is noted that for the bounding case without any friction, all the lateral loads on the core plate will be resisted by the core plate bolts by bending and shear. When friction is considered, a portion of the lateral loads are resisted by friction at the rim and shroud ledge interface resulting in lower lateral loads on the core plate bolts. (a) The licensee is requested to quantify the impact on the core plate stresses for the bounding case without friction and (b) The licensee is also requested to quantify the impact of the additional load on the qualification of core plate when friction is considered.
[proprietary]
Sections 1.0 and 8.1 Finite Element (FE) Model differences: In Section 1.0, it was stated that GEH performed a plant-specific core plate hold down bolt stress analysis for VY, and in Section 8.1 it is mentioned that the analysis does not have a plant-specific FE model, and some calculations use scaled values from BWRVIP-25 data. (a) The licensee is requested to elaborate what items are scaled values from BWRVIP-25 data and (b) The licensee is also requested to provide a table of differences between BWRVIP-25 core plate FE model and VY core plate analysis model along with justification for not having a VY plant-specific FE model.
OffiGial Use Only Proprietary Information
- 2 Please contact me at (301) 415-4125 if you have any questions on this issue.
Sincerely, Ira!
James Kim, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-271
Enclosures:
- 1. RAI (non-proprietary)
- 2. RAI (proprietary) cc w/encl 1: Distribution via Listserv DISTRIBUTION:
PUBLIC RidsNrrDorlLpl1-1 Resource RidsRgn 1 MailCenter RidsNrrLASLittle RidsNrrDeEmcb Resource RidsNrrPMVermontYankee RidsAcrsAcnw _MailCenter Resource CBasanaraju ADAMS ACCESSION NO.: ML113140242 (proprietary), ML113140275 (non-proprietary)
OFFICE NAME DATE NRR/DORL LPL 1-1/PM JKim 11/16/11 NRR/DORL LPL 1-1/LA SUttle 11/16/11 NRR/DE EMCB/BC MMurphy 11/16/11 NRRIDORL LPL1-1/BC NSalgado 11/17111 OFFICIAL RECORD COPY OffiGial Use Only Proprietary Information When Enclosure 2 is detached, this letter and Enclosure 1 are no longer proprietary.