ML20151T417

Requests Relief from Quarterly Stroke Test Requirement for Eight ERCW Valves on Plant Containment Spray Hxs.Revised App C to Util Valve Test Program Encl

ML20151T417
Person / Time
Site:	Sequoyah
Issue date:	04/22/1988
From:	Gridley R TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8804290010
Download: ML20151T417 (5)

Text

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TENNESSEE VALLEY AUTHORITY CH ATTANOOG A. TENNESSEE 37401 SN 1578 Lookout Place APR 221988 U.S. Nuclear Regulatory Comission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:

In the Matter of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 - RELIEF REQUEST FOR EIGHT ESSENTIAL RAW COOLING WATER (ERCW) VALVES ON SQN'S CONTAINMENT SPRAY HEAT EXCHANGERS By letter dated October 23, 1987, from John A. Zwolinski to S. A. White, NRC transmitted to TVA the Safety Evaluation Report (SER) for the SQN In-Service Testing Program (IST) for Pumps and Valvas. This SER granted relief from certain requirements of the American Society of Mechanical Engineers (ASME) Boller and Pressure Vessel Code,Section XI.

Eight ERCH valves that provide. cooling water to SQN's containment spray heat exchangers are currently exercised each quarter to comply with the ASME Section XI code (IWV-3411 of the 1974 Edition through Summer 1975 Addenda [ Uni' il and 1977 Edition through Summer 1978 Addenda (Unit 2]).

Experience has shown that exercising these valves causes raw water to be introduced into the containment spray heat exchangers while they are in wet layup. These heat exchangers are normally kept in wet layup for the purpose of preserving structural integrity (prevent tube pitting and microbiologically induced corrosion). When the introduction of raw water causes chemistry limits to be exceeded, the heat exchangers must be drained, flushed, and refilled with demineralized water and corrosion

. Inhibitors. This is undesirable in tha& (1) the heat exchangers must be declared inoperable during the cleanup /layup operation, and (2) the plant l must enter a Limiting Condition for Operation while in modes 1, 2, 3, or 4.

i Based on the above information, relief is requested from the quarterly stroke test requirement (IWV-3411) for eight ERCW valves on SQN's

, containment spray heat exchangers. The enclosure contains (1) a revised l Appendix C to SQN's valve test program (reference SQN's Final Safety Analysis Report, Section 6.8), and (2) the associated request for relief l

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8804290010 880422 PDR ADOCK 05000327 An Equal opportunity Employer DCD _ _ _ _ , - ,_ _ _

g gg ]ggg U.S. Nuclear Regulatory Commission If you have any questions concerning this issue, please have someone telephone D. V. Goodin at (615) 870-7734.

Very truly yours, TENNESSEE VALLEY AUTHORITY N \ .

R.Gridey, Dire {cto-Nuclear Licensing and Regulatory Affairs Enclosure cc (Enclosure):

Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech, Assistant Director for Projects '

TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379

e . .

a ENCLOSURE Revised Appendix C to Sequoyah Nuclear Plant's (SQN's) In-Service Test Program (SQN Final Safety Analysis Report, Section 6.8) and the Associated Relief Request

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Pt!-23 S_vs tem : Essential Raw Cooling Water' System (ERCW)

Valve FCV-67-123, FCV-67-124, FCV-67-125, FCV-67-12 6 Class: 3 Category: B-Active Function: Open to provide ERCH cooling water flow to the containment spray heat exchanger shell side.

Impractical

. Requirement: Exercise valve on a quarterly basis.

t Basis for Relief: The raw water of the ERCW system contains chlorides which can cause heat exchanger tube pitting, and organisms which can produce microbiologically induced corrosion in the heat exchanger piping and shell. To preserve their integrity, these heat exchangers are placed in wet layup with demineralized water and corrosion inhibiters, and their chemistry is monitored. Whenever.the chemistry specifications are exceeded, the heat exchangers are drained, flushed, and again piteed in layup.

During modes 1, 2, 3, and 4, Technical Specification 3.6.2.1 requires that the plant maintain two independent Containment Spray Systems operable or enter an LCO. When a containment spray best exchanger is drained during the cleanup /layup ,

operation, that containment spray loop is declared inoperable placing the unit in an LCO.

Chemistry data demonstrates that the quarterly cycling of the inlet and outlet heat exchanger valves increases the ingression of raw water, thus forcing the plant to enter the LCO more often to preserve the integrity of the heat exchangers. ,

Alt Testing: Full stroke exercise these valves as required on an alternate frequency.

e i Freguency for l Alt. Testing: Full stroke exercise these valvess i

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1. at least once each refueling outage l

l 2't each time ti.e heat exchanger chemistry requires .

cleanup /layup operations, but at a frequency not to exceed l .once per quarter (92 days).

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