ML20093K942
| ML20093K942 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 10/11/1995 |
| From: | Hagan R WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ET-95-0111, ET-95-111, GL-95-07, GL-95-7, NUDOCS 9510250104 | |
| Download: ML20093K942 (4) | |
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WG) NUCLEAR OPERATI LF CREEK I
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Robert C. Hagan Vce President Engineerag October 11, 1995 ET 95-0111 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 Washington, D. C.
20555
Subject:
Docket 50-482:
Response to Generic Letter 95-07 Gentlemen:
Generic Letter 95-07, " Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves," dated August 17, 1995, requests certain actions be taken by licensees regarding the susceptibility of power-operated gate valves to pressure locking and/or thermal binding.
In response to Generic Letter 95-07, Wolf Creek Nuclear Operating Corporation (WCNOC) will implement the requested actions of Generic Letter 95-07 by providing; 1) the screening criteria for valve susceptibility to pressure locking / thermal binding; 2) the results of this screening, and 3) descriptions of corrective actions taken, or other dispositions.
This will be completed by the 180 day response date of February 14, 1996.
Justifications for extension of this schedule to perform any remaining corrective actions will be provided at that time.
In addition, WCNOC is maintaining involvement with the Westinghouse Owner's Group Pressure Locking / Thermal Binding Subcommittee to monitor valve testing and susceptibility evaluations for Westinghouse Pressurized Water Reactors.
Based on the preliminLry screening evaluation required by Generic Letter 95-07, there are no gate valves at Wolf Creek Generating Station (WCGS) with safety-related opening functions that are equipped with hydraulic or air operators.
The scope of valves affected by the pressure locxing/ thermal l
binding phenomenon at WCGS is limited to motor-operated valves.
Solenoid operated valves and valves in air systems were not considered to be within the scope of this generic letter.
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4 9510250104 951011 4
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PDR P.O. Box 411/ Buriangton, KS 66839 / Phone: (316) 364-8831 An Equal Opportunity Employer WF/HC/ VET
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ET 95-0111 Page 2 of 2 To supp" ort the closure of Generic Letter 89-10, " Safety-Related Motor-Operated Vdive Testing and Surveillance," a complete review of WCGS safety-related motor-operated gate valves was performed during 1994 to the Generic Letter 89-10, Supplement 6,
guidelines.
Of the 79 safety-related motor-operated ge'.
valves, 13 valves were found to be susceptible to pressure locking and/or thermal binding and would have an adverse impact on plant safety upon failing to open.
A basia for current operability or corrective actions taken to ensure operability are provided in the attached table.
If you have any questions concerning this submittal, please contact me at (316) 364-8831, extension 4553, or Mr. Richard D. Flannigan at extension 4500.
Very truly yours, e~
S o
Robert C.
Hagan RCH/jra Attachment cc:
L. J.
Callan (NRC), w/a D.
F.
Kirsch (NRC), w/a J.
F.
Ringwald (NRC), w/a J.
C.
Stone (NRC), w/a l
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STATE OF KANSAS
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SS COUNTY OF COFFEY
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' Robert C. Hagan, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and.-
correct to the best of his knw? edge, information and belief.
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ANGELA E.WESSEL NotaryPublic Stateof Kansas By My Appt.Espires 7-J-99 Rdbe t C. Hagas Vic President Eng neering SUBSCRIBED and sworn to before me this
//04 day of 6 ct.
1995.
Ab Y1 1dde{
NotaryPplic Expiration Date c'
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Current Onerability Basis for Motor-Onerated Valves and Corrective Actions
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"i Valve Number i Valve Function Findings Corrective Actions and Justifications
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EJHV8840 Residual Heat Found to be Plant test procedures have been revised to eliminate the conditions Removal System to susceptible to inducing pressure locking during testing. During operation, valves may E
Hot Leg pressure locking be susceptible if back leakage from RCS occurs through redundant check g
Recirculation only.
valves. Operating procedures currently address generic actions if hot g
Isolation leg recirculation valves fail to open.
The consequences of not Z
achieving Residual Heat Removal hot leg recirculation has been evaluated and the single failure of EJHV8840 alone has no adverse safety impact.
EMHV8802A & B Safety Injection Found to be Plant test procedures have been revised to eliminate the conditions Pump Discharge to susceptible to inducing pressure locking during testing. During operation, valves may RCS Hot Leg pressure locking be susceptible if back leakage from RCS occurs through redundant check Isolation only.
valves. Most recent surveillance indicates back leakage to be insignificant and below the previously evaluated limits for valve function. Operating procedures currently address generic actions if hot leg recirculation valves fail to open.
BBPV8702A & B Residual Heat Found to be No modifications or procedural changes will be made for corrective EJHV8701A & B Removal System susceptible to action because redundant means exist to provide the safety-related Suction from RCS thermal binding function of core cooling and system pressure relief.
Hot Leg Isolation and pressure locking.
ENHV0001 & 7 Containment Spray Found to be A temporary plant modification has been performed to fill the Pump Suction from susceptible to containment recirculation sumps with water in order to insulate the Containment pressure locking valves from LOCA fluid impingement and preclude the temperature change Recirculation Sump only.
that would induce pressure locking.
In addition, WCNOC has planned a Isolation potential modification to these valves during the eighth refueling outage immediately following the 180 day response date.
The potential EJHV8811A & B Residual Heat Found to be modification will eliminate the susceptibility to pressure locking Removal System susceptible to without having the sumps filled with water.
WCNOC will monitor industry suction from pressure locking tests to possibly justify nc, permanent modification. Thermal binding of Containment and thermal EJHV8811A&B is prevented by procedural restrictions.
Recirculation Sump binding.
Isolation EJFCV0610 &
Residual Heat Found to be WCNOC has planned a modification to these valves during the eighth EJFCV0611 Removal Pump susceptible to refueling outage immediately following the 180 day response date.
The Minimum Flow thermal binding modification that may occur after the 180 day period is changing Recirculation under specific electrical control circuitry to close the valve on limit with Valves plant heat-up soft-seating to preclude thermal binding.
The susceptibility of mode transitions.
EJFCV0610 and 611 occurs only on power ascension.
The primary safety function of these valves is to close following a design basis accident.
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