BVY 06-099, 2006/11/06-Vermont Yankee License Renewal Application, Amendment 21 Response to Request for Clarification of SAMA RAIs

2006/11/06-Vermont Yankee License Renewal Application, Amendment 21 Response to Request for Clarification of SAMA RAIs

ML063170080
Person / Time
Site:	Vermont Yankee
Issue date:	11/06/2006
From:	Ted Sullivan Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
%dam200612, BVY 06-099, TAC MC9670
Download: ML063170080 (5)

Text

Entergy Entergy Nuclear Operations, Inc.Vermont Yankee P.O. Box 0500 185 Old Ferry Road Brattleboro, VT 05302-0500 Tel 802 257 5271 November 6, 2006 Docket No. 50-271 BVY 06-099 TAC No. MC 9670 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

1. Letter, Entergy to USNRC, "Vermont Yankee Nuclear Power Station, License No. DPR-28, License Renewal Application," BVY 06-009, dated January 25, 2006.2. Letter, Entergy to USNRC, "Vermont Yankee Nuclear Power Station, License No. DPR-28, License Renewal Application, Amendment 7," BVY 06-071, dated August 01, 2006.3. Letter, Entergy to USNRC, "Vermont Yankee Nuclear Power Station, License No. DPR-28, License Renewal Application, Amendment 18, Response to Request for Clarification of SAMA RAI Responses," BVY 06-095, dated October 20, 2006.Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)License Renewal Application, Amendment 21 Response to Request for Clarification of SAMA RAIs On January 25, 2006, Entergy Nuclear Operations, Inc. and Entergy Nuclear Vermont Yankee, LLC (Entergy) submitted the License Renewal Application (LRA) for the Vermont Yankee Nuclear Power Station (VYNPS) as indicated by Reference

1. On October 26, 2006, a teleconference was conducted with Entergy License Renewal Team representatives and the Nuclear Regulatory Commission (NRC) Environmental Auditors.

The NRC requested clarification for several of the responses provided in Reference 2 and 3. These issues are addressed Attachment 1 to this letter.This submittal does not contain new regulatory commitments.

Should you have any questions, please contact Mr. Dave Mannai at (802) 451-3304.

I declare under penalty of perjury that the foregoing is true and correct, executed on November 6, 2006.Sincerely, drt/tALAIrv, Ted A. Sullivd")Site Vice Przedt Vermont Yankee Nuclear Power Station Attachment 1 cc: See next page 4\q' BVY 06-099 Docket No. 50-271 Page 2 of 2 cc: Mr. James Dyer, Director U.S. Nuclear Regulatory Commission Office 05E7 Washington, DC 20555-00001 Mr. Samuel J. Collins, Regional Administrator U.S. Nuclear Regulatory Commission, Region 1 475 Allendale Road King of Prussia, PA 19406-1415 Mr. Jack Strosnider, Director U.S. Nuclear Regulatory Commission Office T8A23 Washington, DC 20555-00001 Mr. Jonathan Rowley, Senior Project Manager U.S. Nuclear Regulatory Commission 11555 Rockville Pike MS-O-1 1 F1 Rockville, MD 20853 Mr. Richard Emch U.S. Nuclear Regulatory Commission 11555 Rockville Pike MS-O-1 1 F1 Rockville, MD 20853 Mr. James J. Shea, Project Manager U.S. Nuclear Regulatory Commission Mail Stop 08G9A Washington, DC 20555 USNRC Resident Inspector Entergy Nuclear Vermont Yankee, LLC P.O. Box 157 (for mail delivery)Vernon, Vermont 05354 Mr. David O'Brien, Commissioner VT Department of Public Service 112 State Street -Drawer 20 Montpelier, Vermont 05620-2601 Diane Curran, Esq.Harmon, Curran, Spielberg

& Eisenberg, LLP 1726 M Street, N.W., Suite 600 Washington, D.C. 20036 BVY 06-099 Docket No. 50-271 Attachment 1 Vermont Yankee Nuclear Power Station License Renewal Application Amendment 21 VERMONT YANKEE NUCLEAR POWER STATION LICENSE RENEWAL APPLICATION ATTACHMENT 1 10/26/2006 Teleconference Clarification Items A teleconference was held on 10/26/06 with the NRC and VYNPS License Renewal Team. During this call, the NRC requested additional information pertaining to fire and flood risk contributors to ensure that VYNPS evaluated each of the contributors for scenario-specific remedies, and did not find any that were cost effective (with exceptions as stated below).RAI 5.e Clarification The clarification of response to the request for additional information (RAI) RAI 5.e in Amendment 18 indicated that there are now only 9 risk significant terms involving internal flooding initiators.

As indicated in revised Environmental Report (ER) Table E.1-3, two of the flood scenarios are addressed by Phase II Severe Accident Mitigation Alternatives (SAMA) SAMA 47, "Shield injection system electrical equipment from potential water spray." Flood-specific improvements identified by the Individual Plant Examination for External Events (IPEEE) have already been implemented to address specific flood scenarios.

The flood scenarios were systematically reviewed as part of the 2002 Probabilistic Safety Assessment (PSA) model update (in which the internal flood events model was updated) to determine if additional improvements could be identified to reduce the internal flood Core Damage Frequency (CDF) contribution.

With the exception of the improvement which has been included as Phase II SAMA 47, no additional cost-beneficial alternatives were identified.

RAI 5.q Clarification There are eight (8) dominant fire initiated events. All of the associated fire compartments are equipped with fire detection, and all except two (2) of the fire compartments are protected by an automatic fire suppression system. The exceptions are the control room (control bldg 272' elev.) and the Control Rod Drive (CRD) repair room (reactor bldg 252'-south elev.).The control room is continuously occupied.

An auto-suppression system would need to be acceptable with regard to health risks associated with continued occupation of the space. Some thought was given to use of a fixed auto-suppression system for the control room utilizing FM-200 (a replacement for the ozone depleting Halon) for the suppression agent. However, the current fire detection system may or may not be usable for actuation.

In addition, some amount of sealing of the cabinets would be required.Also, migration of the suppression agent within the panel enclosure would need to be considered.

For example, on the main bench-board, there may be undesirable consequences associated with filling the entire enclosure with suppression agent because non-fire affected electrical contacts and circuits could be damaged. For these reasons an auto-suppression system for this space was judged to be inappropriate.

Rerouting of cables or relocation of equipment out of the control room is not practical due the need for a centralized control location.Page 1 of 2 BVY 06-099 Docket 50-271 VERMONT YANKEE NUCLEAR POWER STATION LICENSE RENEWAL APPLICATION ATTACHMENT 1 The CRD repair room is located on the south side of reactor building, on the 252'elevation.

A water suppression system would not be practical since the main steam tunnel communicates with this room through an open door. A High Energy Line Break (HELB) which occurred in this room would likely cause the water suppression system to discharge, resulting in a flooding hazard. Likewise a C02 suppression system would require sealing of the room, which would have undesirable consequences in that this path is credited for pressure relief for a HELB within the main steam tunnel. For these reasons an auto-suppression system for this space was judged to be inappropriate.

Control cables for both emergency diesel generators and control cables for 2 of the 4 Safety Relief Valves (SRVs) are routed through this room. Since rerouting control cables would require extensive modifications, it was judged to be not cost beneficial.

Additional Clarification As noted in revised ER Table E.1-3, Phase I SAMAs including improvements to plant procedures, and installation of instrumentation to enhance the likelihood of success of operator action in response to accident conditions, have already been implemented.

No additional Phase II SAMAs were recommended for this subject because potential improvements would involve major, and very costly, design changes. To automate these functions, significant design changes would be necessary to upgrade the Structures, Systems and Components (SSCs) relied upon for alternate injection from non-safety-class to safety-class.

The firewater system components and support system relied upon for alternate injection would need to be upgraded to comply with seismic safety-class standards.

Similarly, the John Deere diesel generator electrical switchgear would need to be upgraded to comply with electric safety-class standards.

For these reasons, automation of the alternate injection system was judged to be not cost beneficial.

Page 2 of 2 BVY 06-099 Docket 50-271