ML20211E884

Requests That Licensee Provide bldg-specific Justification for Use of Method A.1 at Locations Where Amplification Significantly Exceeds 1.5 Limit Above 8 Hz

ML20211E884
Person / Time
Site:	Vermont Yankee
Issue date:	08/25/1999
From:	Croteau R NRC (Affiliation Not Assigned)
To:	Wanczyk R VERMONT YANKEE NUCLEAR POWER CORP.
References
TAC-M69490, NUDOCS 9908300155
Download: ML20211E884 (3)

Text

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1 Mr. Robert J. Wenczyk

• Acting Director of Op:r.itions August 25, 1999 l Vzrmont Ycnkta Nucl: r Pow r Corpcration 185 Old Ferry Roid Brattleboro, VT 05301

SUBJECT:

VERMONT YANKEE NUCLEAR POWER STATION, REQUEST FOR ADDITIONAL INFORMATION REGARDING VERIFICATION OF SEISMIC ADEQUACY OF MECHANICAL AND ELECTRICAL EQUIPMENT (TAC NO. M69490)

Dear Mr. Wanczyk:

On August 11,1999, we held a telephone conference with members of your staff regarding unresolved safety issue (USI) A-46 at Vermont Yankee. One of the items discussed was your use of Generic Implementation Procedure, Revision 2 (GlP-2) Method A.1 for the comparison of seismic capacity to seismic demand. Additional information is needed in this area in order for us to confirm conformance with or assess the acceptability of deviations from the GIP-2 criteria.

GIP-2 provides for several methods of comparing seismic capacity to seismic demand. Method A.1 compares the Seismic Qualification Utility Group (SOUG) bounding spectrum to the plant's safe shutdown earthquake (SSE) ground response spectrum. GIP-2 places limitations on the use of Method A.1. These limitations are that the SSE ground response spectrum can be used for comparison to the bounding spectrum when: (1) the equipment is mounted in the nuclear plant at an elevation within approximately 40 feet of the effective grade; (2) the equipment, including its supports, has a fundamental natural frequency greater than about 8 Hz; or (3) the amplification factor between the free field ground response spectrum and the in-structure response spectra (IRS) is not more than about 1.5.

A review of the Vermont Yankee IRS to the ground response spectrum ratio at locations where GIP-2 Method A.1 was used indicates that the amplification factors, above 8 Hz, of some of these IRS appear to be significantly above the 1.5 limit set by GIP-2. We request that you provide a building-specific justification for the use of Method A.1 at the locations where the amplification significantly exceeds the 1.5 limit above 8 Hz.

Please provide a response to this request for additional information within 60 days of receipt of this letter, as discussed with Mr. Gautam Sen on August 19,1999.

Sincerely, RkcNrbNrM, Rdject Manager, Section 2 Project Directorate l Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-271 cc: See next page DISTRIBUTION { g l' C Docket File PUBLIC E. Adensam PDI-2 Rdg. K. Manoly J. Zwolinski/S. Black R. Croteau OGC ACRS C. Anderson, RI DOCUMENT NAME: G:\PDI-2\ Vermont \RA169490-2.wpd Tc receive a copy of this document, indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with rttachment/ enclosure "N" = No copy OFFICE PM:PDI-2 C LA:PDl-2 lC EMEB C SCdBDi-2 l NAME RCroteat@ TClark MP KManloy /"V JClifford I DATE 08F/99 ' 08/)d99 8/ M99 T h5 /99 OFFICIAL RECORD COPY n

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% ***** / August 25, 1999 Mr. Robert J. Wanczyk Acting Director of Operations Vermont Yankee Nuclear Power Corporation-185 Old Ferry Road Brattleboro, VT 05301 SU53 JECT: VERMONT YANKEE NUCLEAR POWER STATION, REQUEST FOR ADDITIONAL INFORMATION REGARDING VERIFICATION OF SEISMIC ADEOUACY OF MECHANICAL AND ELECTRICAL EQUIPMENT (TAC NO.

M69490)

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Dear Mr. Wanczyk:

On August 11,1999, we held a telephone conference with members of your staff regarding unresolved safety issue (USI) A-46 at Vermont Yankee. One of the items discussed was your use of Generic implementation Procedure, Revision 2 (GIP-2) Method A.1 for the comparison of seismic capacity to seismic demand. Additional information is needed in this area in order for us to confirm conformance with or assess the acceptability of deviations from the GIP-2 criteria.

GIP-2 provides for several methods of comparing seicmic capacity to seismic demand. Method A.1 compares the Seismic Qualification Utility Group (SOUG) bounding spectrum to the plant's safe shutdown earthquake (SSE) ground response spectrum. GIP-2 places limitations on the use of Method A.1. These limitations are that the SSE ground response spectrum can be used for comparison to the bounding spectrum when: (1) the equipment is mounted in the nuclear plant at an elevation within approximately 40 feet of the effective grade; (2) the equipment, including its supports, has a fundamental natural frequency greater than about 8 Hz; or (3) the amplification factor between the free field ground response spectrum and the in-structure response spectra (IRS) is not more than about 1.5.

A review of the Vermont Yankee IRS to the ground response spectrum ratio at locations where GIP-2 Method A.1 was used indicates that the amplification factors, above 8 Hz, of some of these IRS appear to be significantly above the 1.5 limit set by GIP-2. We request that you provide a building-specific justification for the use of Method A.1 at the locations where the amplification significantly exceeds the 1.5 limit above 8 Hz Please provide a response to this request for additional information within 60 days of receipt of this letter, as discussed with Mr. Gautam Sen on August 19,1999.

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't i Richard P. Croteau, Project Manager, Section 2 Project Directorate i Division of Licensing Project Management Othe of Nuclear Reactor Regulation Docket No. 50-271 cc: See next page

e . . i Vermont Yankee Nuclear Power Station cc:

Regional Administrator, Region i Mr. R::ymond N. McCandless 1- U. S. Nuclear Regulatory Commission . Vermont Department of Health 475 Allendale Road Division of Occupational King of Prussia, PA 19406 and Radiological Health 108 Cherry Street Mr. David R. Lewis Burlington, VT 05402 Shaw, Pittman, Potts & Trowbridge 2300 N Street, N.W. Mr. Gautam Sen Washington, DC 20037-1128 Licensing Manager Vermont Yankee Nuclear Power Mr, Richard P. Sedano, Commissioner Corporation Vermont Department of Public Service 185 Old Ferry Road 112 State Street Bratueboro, VT 05301 Montpelier, VT 05620-2601 Resident inspector Mr. Michael H. Dworkin, Chairman Vermont Yankee Nuclear Power Station Public Service Board U. S. Nuclear Regulatory Commission State of Vermont P.O. Box 176 112 State Street Vernon, VT 05354 Montpelier, VT 05620-2701 Director, Massachusetts Emergency Chairman, Board of Selectmen Management Agency Town of Vernon ATTN: James Muckerheide P.O. Box 116 400 Worcester Rd.

Vernon, VT 05354-0116 P.O. Box 1496 Framingham, MA 01701-0317 Mr. Richard E. McCullough Operating Experience Coordinator Jonathan M. Block, Esq.

Vermont Yankee Nuclear Power Station Main Street '

P.O. Box 157 P. O. Box 566 Governor Hunt Road Putney, VT 05346-0566 Vernon, VT 05354 G. Dana Bisbee, Esq.

Deputy Attorney General 33 Capitol Street Concord, NH 03301-6937 Chief, Safety Unit I

Office of the Attorney General One Ashburton Place,19th Floor Devaan, MA 02108 Ma Deborah B. Katz Box 83 Shelbume Falls, MA 01370

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