ML20134G166

Forwards Suppl Response to GL 95-07, Pressure Locking & Thermal Binding of SR Power Operated Gate Valves

ML20134G166
Person / Time
Site:	Mcguire, McGuire
Issue date:	02/03/1997
From:	Barron H DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-95-07, GL-95-7, NUDOCS 9702100302
Download: ML20134G166 (5)

Text

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• Dukehutwr Company y y jw;m, l McGuar Nudear Gmeration ikpartnus:t g ;(., p,gj,,y 127% Magn RnyRoad(MG01>F) (p;g5549, j lhmtmt sue, NC280M31f)  ;

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DUKEPOWER February 3, 1997 l U. S. Nuclear Regul.1 tory Commission ,

Document Control Desk  !

l Washington, D.C. 20555 t

Subject:

McGuire Nuclear Station Docket Nos. 50-369, 370 Generic Letter 95-07, " Pressure Locking and Thermal Binding 9 i

of Safety-Related Power-Operated Gate Valves"  ;

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On August 17, 1995, the NRC issued Generic Letter 95-07, " Pressure  !

Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves  !

to request that licensees take actions to ensure that safety-related k power-operated gate valves that are susceptible to pressure locking or i thermal binding are capable of performing their safety functions. l I

Duke Power responded to the Generic Letter per M. S. Tuckman's letter  !

dated February 13, 1996. On July 31, 1996, McGuire provided an  !

additional response to the NRC's Request for-Additional Information l dated July 1, 1996. Please find attached a supplemental response to i

Generic Letter 95-07 as a result of recent NRC inspection activities.

McGuire commits to implement the corrective actions as outlined in the L

amended response. i' i

Questions or problems should be directed to Kay Crane, McGuire l Regulatory Compliance at (704) 875-4306. i l

a Very truly yours, i H. B. Barron, Vice President 1 j McGuire Nuclear Station Attachment i i

9702100302 970203 PDR ADOCK 05000369 i p PDR l

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t U. S.11uclear Regulatory Commission '

09cument Control Desk  ;

Page 2  ;

j cc: Mr. Victor Nerses, Project Manager  !

l U. S. Nuclear Regulatory Commission [

l Office of Nuclear Reactor Regulation i l

Washington, D.C. 20555 ,

t Mr. Luis Reyes  !

Regional Administrator, Region II  ;

U. S. Nuclear Regulatory Commission j 101 Marietta St., NW, Suite 2900 i Atlanta, GA 30323 Mr. Scott Shaeffer i Senior Resident Inspector l McGuire Nuclear Station l l

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McGuire Nuclear Station NRC Generic Letter 95-07 Pressure Locking and Thermal Binding Amended Response Previous Responses (1) Original Response - February 13,1996 (2) Request for AdditionalInformation Response - July 31,1996

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o McGuire Nuclear Station Generic Letter 95-07. Pressure Locking and Thermal Binding l Amended Response IFW0027A & 2FWOO27A Valve Apolication: Refueling water storage tank supply isolation Corrective Actions: In order to avoid long term reliance on check valve leak tightness to prevent pressure  !

locking, these valves will be modified during the 1/2EOClI refueling outages to preclude any potential pressure locking effects.

l ILD0108A,ILDell3B,2LD0108A & 2LD0113B I

Valve Anolication: Diesel generator full flow lube oil filter bypass isolations ,

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( Corrective Actions: In order to avoid long term reliance on calculation methods, these valves will be i

modified during the 2EOClI and IEOCl2 refueling outages to preclude any potential pressure locking i 1

effects.

l INC0031B,INC0033A,INC0035B,2NC0031B,2NC0033A & 2NC0035B i l

Valve Annlication: Pressurizer PORV Block Valves Corrective Actions: INC0031B, INC0033A,2NC0031B and 2NC0033A will be modified during or before the 1/2EOCl3 refueling outages to preclude any potential thermal binding effers.1/2NC0031B and 33A, the block valves for pressurizer PORV's 1/2NC0032B and 34A, are required to be open during Low Temperature Overpressure Protection (LTOP) conditions. The concern is a fast shutdown where the valves f are closed and must be re-opened prior to attaining LTOP conditions. Tech Spec 3.4.9.3 requires that two l PORV's (1/2NC0032B and 34A) with a lift setting of less than or equal to 385 psig be operable during  !

mode 4 when the temperature of any RCS cold leg is less than or equal to 300 degrees F, mode 5, and mode 1 6 when the head is on the reactor vessel. No corrective actions are planned for 1/2NC0035B since these

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valves are not required for LTOP protection. i i

IND0058A & 2ND0058A ; IN10136B & 2N10136B i

Valve annlication: Low head injection pump discharge to high & medium head injection pump isolation.

Corrective Actions: These valves will be modified during the 1/2EOCl1 outages to preclude any potential i pressure locking effects.

IN10009A, INI0010B,2N10009A and 2NI0010B Valve Apolication: High head injection pump discharge to cold leg isolation Pressure Lockine Evaluation: In accordance with the Duke Power Company pressure locking screening criteria, these valve applications are potentially susceptible to pressure locking since they are of the flex wedge design. In the previous response, dated 7/31/96,it was indicated that these valves are not subject to pressure locking since they would open with NV pump discharge pressure acting against one side of the wedge. Since this submittal there has been a discussion concerning the time differential between pump start and valve opening. To further clarify th,; icenario, for a LOCA coincident with a LOOP event, the power to the NV pumps and these valves would be restored at the same time. The most recent ESF Actuation Test results show that the slowest starting NV pump develops full pressure within 1.8 seconds. Based on past bench testing experience, these MOV's can be expected to operate at locked rotor for 4-5 seconds.

Corrective Action: For the short term, the data from future ESF tests will be reviewed to ensure the NV l pump start does not extend beyond the ability of the valve to survive at locked rotor conditions. For the

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, McGuire Nuclear Station ,

Generic Letter 95-07. Pressure Locking and Hermal Binding l

- Amended Response l

long term, these valves will be modified during the 2EOC1I and IEOCl2 outages to preclude any potential  ;

occurrence of pressure locking. '

i INS 0001B, INS 0018A,2NS0001B & 2NS0018A I 1

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Valve Application: Containment spray pump suction containment recirculation sump isolations 5

Corrective Actions: In order to prevent long term reliance on calculational methods, these valves will be  !

modified during 1/2EOCl1 to preclude any potential pressure locking effects. j l

l 1NS0012B,1NS00158,1NS0029A,1NS0032A,2NS0012B,2NS0015B,2NS0029A & 2NS0032A l

Valve anchcation: Containment spray header isolations l l

l Corrective Actions: ne controlling procedures for quarterly running of the NS pumps will be revised by i 4/30/97 to include stroking open these valves after completion of the applicable train's pump run. His will I

eliminate the mechanism for inducing any potential pressure locking effects.

] 1NS0038B,1NS0043A,2NS00388 & 2NS0043A j Valve Application: Low injection pump discharge to auxiliary containment spray isolations Corrective Actions: Rese valves will be modified during 1/2EOCl1 outages to preclude any potential

pressure locking effects.

INV0221 A, INV0222B,2NV0221 A & 2NV02228 Valve Application: liigh head injection pump suction refueling water storage tank (FWST) isolations Corrective Actions: He 7/31/96 response to GL 95-07 indicated that either modifications or procedural changes would be made to satisfy the long term pressure locking concern for these valves. Modifications ,

will be made during the 1/2EOCl1 outages to preclude any potential pressure locking effects.

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