ML20207A854

Forwards RAI Re Licensee Listed Responses to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves. Response Requested within 90 Days of Submittal Date

ML20207A854
Person / Time
Site:	North Anna
Issue date:	05/20/1999
From:	Kalyanam N NRC (Affiliation Not Assigned)
To:	Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
References
GL-95-07, GL-95-7, TAC-M93490, TAC-M93491, NUDOCS 9905270342
Download: ML20207A854 (5)

Text

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May 20, 1999 Mr. J. P. O'Hinlon Senior Vice Pr;sident Virginia El ctric end Power Comp;ny 5000 Dominion Boulevard Glen A!!en, VA 23060 S"UBJECT:

GENERIC LETTER (GL) 95-07," PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES,"

REQUEST FOR ADDITIONAL INFORMATION, NORTH ANNA POWER STATION, UNITS 1 AND 2 (NAPS 1 AND 2);(TAC NOS. M93490 AND M93491)

Dear Mr. J. O'Hanlon:

On August 17,1995, the staff issued Generic Letter (GL) 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 power-oprated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions. You responded to the GL on October 16,1995, November 15,1995, February 7,1996, and July 3,1996. The last letter was in response to our request for additional information (RAl) dated June 6,1996.

The staff has reviewed your responses contained in the letter dated July 3,1996, and requires further information to complete its review of your responses. The enclosure to this letter forwards staff's inquiries in the form of an RAl.

The staff ~ r sts a response to the RAI within 90 days of the submittal date. This submittal date was oiscussed with Mr. Tom Shaub of your staff on May 14,1998, who later indicated that VEPCO will be able to meet this date. The staff appreciates the efforts expended with respect to this matter.

Sincerely, or'iginal signed by:

N. Kalyanam, Project Manager, Section 1 Project Directorate ll Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos.: 50-338 and 50-339

Enclosure:

Request for AdditionalInformation i

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May 20, 1999

' Mr. J.- P. O'Hanlon Senior Vice President Virginia Electric and Power Company 5000 Dominion Boulevard Glen Allen, VA 23060

SUBJECT:

GENERIC LETTER (GL) 95-07, " PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES,"

REQUEST FOR ADDITIONAL INFORMATION, NORTH ANNA POWER STATION, UNITS 1 AND 2 (NAPS 1 AND 2); (TAC NOS. M93490 AND M93491)

Dear Mr. J. O'Hanlon:

On August 17,1995, the staff issued Generic Letter (GL) 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 power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions. You responded to the GL on October 16,1995, November 15,1995, February 7,'1996, and July 3,1996. The last letter was in response to our request for additional information (RAI) dated June 6,1996.

The staff has reviewed your responses contained in the letter dated July 3,1996, and requires further information to complete its review of your responses. The enclosure to this letter forwards staff's inquiries in the form of an RAl.

The staff requests a response to the RAI within 90 days of the submittal date. This submittal date was discussed with Mr. Tom Shaub of your staff on May 14,1998, who later indicated that VEPCO will be able to meet this date. The staff appreciates the efforts expended with respect to this matter.

Sincerely, N. Kalyanam, Project Manager, Section 1 Project Directorate ll Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos.: 50-338 and 50-339

Enclosure:

Request for AdditionalInformation cc w/ encl: See next page

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b Mr. J. P. O'Hanlon Nor1h Anna Power Staton Virginia Electric & PowerCompany Units 1 and 2 cc:

Mr. J. Jeffrey Lunsford Mr. W. R. Matthews CountyAdministrator Site Vice President Louisa County North Anna Power Station P.O. Box 160 P. O. Box 402 Louisa, Virginia 23093 Mineraf. Virginia 23117 Mr. Donald P. Irwin, Esquire Mr. E. S. Grecheck Hunton andWisams Site Vice President Riverfront Plaza, East Tower Surry Power Staton 951 E. Byrd Street Virginia Electric and Power Company Richmond, Virginia 23219 5570 Hog Island Road Surry, Virginia 23883 Dr. W. T. Lough Virginia State Corporation Robert B. Strobe, M.D., M.P.H.

Commission State Health Commissioner Division of Energy Regulalon Office of the Commissioner P. O. Box 1197 Virginia Department of Health Rider &d, Virginia 23209 P.O. Box 2448 Ridsvgd, Virginia 23218 Old Dominion Electric Cooperative 4201 Dominion Blvd.

i Glen Allen, Virginia 23060 Mr. J. H. McCarthy, Manager Nuclear Ucensing & Operatons Support Virginia Electric and Power Company irmnM TechnicalCenter 5000 Dominion Blvd.

Glen Alen, Virginia 23060 Office of the Attomey General Commonwealth of Virginia 900 East Main Street Richmond, Virginia 23219 Senior Residentlispevg North Anna Power Staton U.S. Nuclear Regulatory Commission 1024 Haley Drive Mineral, Virginia 23117 e

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3 SECOND REQUEST FOR ADDITIONAL INFORMATION NORTH ANNA POWER STATION RESPONSE TO GENERIC LETTER 95-07.

" PRESSURE LOCKING AND THERMAL BINDING OF SAFETY-RELATED POWER-OPERATED GATE VALVES" 1.

Your submittal dated July 3,1996, stated that calculations were used to demonstrate that the high head safety injection (HHSI) pump discharge to attemate reactor coolant system (RCS) cold leg valves,1(2)-SI-MOV-1(2)836, and the HHSI pump discharge to RCS hot

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leg valves,1(2)-SI-MOV-1(2)869A/B, would operate during pressure locking conditions.

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Verify that the temperatures of the valves do not increase during the recirculation phase of a postulated accident and that the 0.3 valve factor and 0.2 stem factor used in your pressure locking calculations are consistent with GL 89-10 Program valve and stem factors.

2.

Your submittal dated July 3,1996, states that the boron injection tank outlet valves, 1(2)-SI-MOV-1(2)867C/D, are not susceptible to pressure locking because it is acceptable for the actuators to operate for a short period of time under locked rotor conditions. The

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actuators will operate at locked rotor until an HHSI pump develops full discharge pressure and the boron injection tank inlet valves,1(2)-SI-MOV-1(2)867A/B, partially open.

NRC Inspection Report 50-338,339/97-01 states that the actuators for the casing cooling pump discharge isolation valves 1(2)-RS-MOV-1(2)00A/B and the quench spray pump discharge valves 1(2)-QS-MOV-1(2)01 A/B, may operate at locked rotor conditions until the casing cooling and quench spray pumps develop full discharge pressure.

The NRC has accepted operation of motor-operated valve motor actuators for approximately 1 second at locked rotor conditions because testing performed by Idaho National Engineering and Environmental Laboratory (NUREG/CR-6478) demonstrates that the capability of the actuator does not degrade for that period of time.

Explain how long valves 1(2)-SI-MOV-1(2)867C/D,1(2)-RS-MOV-1(2)00A/B and 1(2)-QS-MOV-1(2)01 A/B would operate at locked rotor conditions. If greater than approximately 1 second, then explain how any reduction in actuator capability due to operation at locked rotor was accounted for or describe any testing that demonstrates that actuator capability will or will not degrade after operating at locked rotor for greater than approximately 1 second.

ENCLOSURE

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Explain why the pressurizer power-operated relief valve (PORV) block valves, 1-RC-MOV-1535,1-RC-MOV-1536 and 2-RC-MOV-2535, are not susceptible to thermal binding when the valves are shut at approximately 650*F to isolate a leaking pressurizer PORV and then cool down after the loop seal reforms (2-RC-MOV-1536 is not susceptible to thermal binding because it is equipped with a compensating spring pack). These valves are required to be capable of opening during a steam generator tube rupture event.

Discuss any operational experience that demonstrates that the valves are not susceptible to thermal binding.

4.

In Attachment 1 to GL 95-07, the NRC staff requested that licensees include consideration of the potential for gate valves to undergo pressure locking or thermal binding during surveillance testing. Valve stroke time testing is considered a surveillance test. During workshops on GL 95-07 in each Region, the NRC staff stated that, if closing a safety-related power-operated gate valve for test or surveillance defeats the capability of the safety system or train, the licensee should perform one of the following within the scope of j

GL 95-07:

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a.

Verify that the valve is not susceptible to pressure locking or thermal binding while

closed, b.

Follow plant technical specifications for the train / system while the valve is closed, c.

Demonstrate that the actuator has sufficient capacity to overcome these phenomena, or d.

Make appropriate hardware and/or procedural modifications to prevent pressure locking and thermal binding.

Verify that normally open, safety-related power-operated gate valves, which are closed for surveillance but must retum to the open position, were evaluated in accordance with one of these criteria.

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