ML20137S438

Provides Addl Info GL 95-07, Pressure Locking & Thermal Binding of SR Power Operated Gate Valves

ML20137S438
Person / Time
Site:	Catawba
Issue date:	04/04/1997
From:	Mccollum W DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-95-07, GL-95-7, TAC-M93446, TAC-M93447, NUDOCS 9704150131
Download: ML20137S438 (4)

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, ;- ll l l l- Dukei\nrer Company WiluanR. 4ktatwat, Je l Catauha Nuclear Generation ikpartment Ske hesident i 4300 Concordhbad (SW101330 Offace

,  % t SC.5745 (803)DlJD6 Fax DUKE PO'NER l

l l April 4,'1997-U. S. Nuclear Regulatory Commission Attention: Document Control Desk l Washington,.D.C. 20555

Subject:

Catawba Nuclear Station, Units 1 and 2 i

Dockets Nos. 50-413 and 50-414 j l Request for Additional Information Regarding {

GL 95-07, " Pressure. Locking and Thermal Binding of i Safety Related Power Operated Gate Valves" (TAC NOS. M93446 and M93447) l l By letter dated February 19, 1997 the NRC requested additional information regarding the Pressure Locking and l

Thermal Binding of Safety Related Power Operated Gate Valves as discussed in conference calls on January 23 and February 10, 1997. Changes in some of the GL 95-07 commitments i required a response detailing the changes. The timeliness  !

of this response meets the requested period of 45 days. i Please review the additional information and contact Martha 1

. Purser (803) 831-4015 with any questions.

Sincerely, e

fY ~ W/W William R. McCollum, J .

g

(

.t c (with attachments):

L L.A. Reyes, Regional Administrator, Region II

i. P.S. Tam, Senior Project Manager, ONRR R.J. Freudenberger, Senior Resident Inspector, CNS 9704150131 970404 I*

PDR' ADOCK 05000413'

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Duke Power Company Catawba Nuclear Station, Units 1 and 2 March 31, 1997 Response to NRC Request for Additional Information ,

NRC GL 95-07: Pressure Locking and Thermal Binding of f Safety-Related Power-Operated Gate Valves  !

j Request dated February 19, 1997 i

l 1. Valves 1 (2) ND028A, 1(2)NI136B, 1 (2) NS001B , 1(2)NS018A,

! 1(2)NS038B, 1(2)NSO43A, 1 (2) NV252A, 1 (2) NV253B ,

1 (2) NI121A, 1 (2)NI152B, 1 (2) NIOO9A, and 1(2)NIO10B:

l Each of these valves will be modified to preclude pressure l locking. The refueling outage when each valve is currently ,

planned for modification is listed below:

1(2)ND028A and 1(2)NI136B RER Supply to Charging System Valve 1 ND 028A will be modified during U1EOC10 in the fall of 1997. Valve 2 ND 028A will be modified during U2EOC10. l l The modification to 1NI136B will be performed during i

U1EOC12. Valve 2NI136B will be modified during the U2EOC9 ,

refueling outage in the fall of 1998. l 1 (2)NS001B and 1 (2)NS018A Containment Spray Pump ,

Containment Sump Suction l l

l Both 1NS001B and 1NS018A will be modified during U1EOC10 in l the fall of 1997. The modifications to Unit 2 NS001B and NS018A will be made during U2EOC9.

1(2)NS038B and 1(2)NSO43A RER Containment Spray Header Modifications to preclude pressure locking will be made to 1NS038B and 1NS043A during U1EOC11. The Unit 2 valves in this same application will be modified during U2EOC10.

1(2)FV252A and 1(2)NV253B Charging Pump Suction Valves 1NV252A and 1NV253B will be modified during U1EOC12.

'Both 2NV252A and 2NV253B will be modified during U2EOC10.

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e l'(2)NI121A and 1(2)NI152B SI Pump Hot Leg Injection Tnese Unit 1 valves will be modified during refueling a

outage U1EOC11. Valve 2NI152B will be modified during

U2EOC9, but 2NI121A will be modified at the following Unit 2 outage, U2EOC10.

1(2)NIOO9A and 1(2)NIO10B Chemical and Volume Control Pump Cold Leg Injection Isolation Valve 1NI009A will be modified during the upcoming U1EOC10

} outage in the fall of this year. 1NIO10B will be modified during refueling outage UlEOC12. Both Unit 2 valves will be modified during U2EOC9 in the fall of 1998.

2. Valves 1(2) ND032A and 1(2) ND065B RHR Hot Leg Injection During Catawba's initial GL 95-07 response, these valves were not evaluated for PL/TB concerns because the current UFSAR licensing basis does not take credit for RHR Hot Leg Recirculation. The following is the PL/TB evaluation for these valves

VALVE TAG NUMBERS: 1(2) ND 032A, 065B

, Valve Application: Nuclear Decay-RHR (ND) Pump Hot Leg j Injection Isolation Gate design: Flex Wedge

Manufacturer

Westinghouse i

i Safety function: Normally open for cold leg injection;  !

closed for cold leg recirculation to provide train  !

i separation and passive failure protection in the manual  !

J alignment for cold leg recirculation. Note: Only the LOCA will be addressed, since Non-LOCA accidents do not require q sump recirculation.

Pressure Locking / Thermal Binding Evaluation: Once this valve is closed after transferring to cold leg recirculation, the only reason for opening the valve is to 1 align the ND System for hot leg recirculation in order to I prevent boron precipitation in the core. When the valve is l

, closed, ND pump discharge pressure is 210 psig (maximum),

and the temperature is 190 degrees F (maximum). When the valve is opened for hot leg recirculation 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> into an accident, there would be pump discharge pressure on upstream side of the valve, precluding hydraulically-induced pressure

. loeking. If the piping between the valve and the pump were to rupture, pressure could be trapped in the valve's bonnet.

However, in that scenario, there would be no need to open the valve since ' either NI pump is capable of providing enough recirculation flow. Additionally, at hot leg recirculation when the valves are required to open, the ND system temperature would not exceed the temperature at valve closure. Therefore, thermally-induced pressure locking is not probable. Also, since the conditions at valve opening do not exceed the thermal binding screening criteria, thermal binding of these valves is not probable.

Conclusion:

These valves are not susceptible to pressure locking or thermal binding.

l Corrective Actions: None.

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l 3 valves 1 (2 ) NS012B , 1 (2 ) NS015B , 1 (2 ) NS029A, and 1(2)NS032A Containment Spray Headers Isolation l The NS System Operating Prcrcdures, OP/1/A/6200/07 and OP/2/A/6200/07, are being revised to include steps that ensure these valves will be cycled after any evolution that could potentially pressurize the valves' bonnets. The procedure changes are currently being reviewed, and are in the approval process. Catawba PIP 0-C-95-1980 corrective l action #9 will track this item to completion.

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