PNO-V-92-024, on 920711,while Retesting Main Steam SRV at Approx 14% Reactor Power,Srv 3B Opened When Operated from Control Room But Would Not Close.Reactor Operators Reduced Reactor Pressure in Effort to Reseat Valve
| ML20203F341 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 07/13/1992 |
| From: | Johnson P, Johnston K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| References | |
| PNO-V-92-024, PNO-V-92-24, NUDOCS 9712170351 | |
| Download: ML20203F341 (1) | |
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pu*.iQ/Ujl PxtLIMINARY NOTIFICATION OF EVENT.0R UNUSUAL OCCURRENCE--PN59224 Date 07/13/92 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by Region y staff on this date.
FACILITY: WASHINGTON PUBLIC POWER SUPPLY SYSTEM Emergency Classification WNP-2 X Notification of Unusual Event DOCKET NO. 50-397 Alert RICHLAND, WASHINGTON Site Area Emergency General Emergency Not Applicable 4
SUBJECT:
FAILURE OF SAFETY / RELIEF VALVE 10 CLOSE (REACTOR SCRAM / UNUSUAL EVENT)
At1:40p.m.(alltimesPDT)onJuly 11, 1992, while retesting main steam safety / relief valves (SRVs) at approximately 14% reactor power, SRV 30 opened when operated from the control room, but would not close. Reactor operators reduced reactor pressure from 950 to 920 psig, and then to 900 psig in an effort to resent the valve. The plant was canually scrammed after two minutes, as p'rescribed by the Technical Specifications. The valve closed 12 seconds later. All rods fully,,Jsserted and the plant continued with a norgal shutdown. An Unusual Event was declared at 1:40 p.m. and terminated at 2:07 p.m.
. event is similar to a July 6, 1992 event, when SRV 3B was opened during testing and e:uld not close. At that time, WNP-2 was in the process of initial startup with the reactor at 14% power.
SRV 38 is one of four reworked SRVs which were installed dur:ng the refueling outage after having been sent offsite for setpoint testing by a contractor However, unlike the other three SRVs, SRV 3B rework included replacement of the valve stem and the bellows. The July 11, 1992 event followed inspection and testing of these four SRVs. The licensee replaced the actuator solenoid on the 3R SRV after investigation concluded this to have caused the earlier failure.
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The lic~ensee has taken the reactor to cold shutdown to continue investigation of SRV 38.
The licensee plans to remove SRV 38, with vendor supervision, and send it to an offsite contractor for investigation, refurbishment, and testing. A detailed root cause assessment plan is presently being finalized. The SRVs at WNP-2 are Crosby Model No. 6XRX10 Style HB-65B dual function vahes.
'The. Senior Resident inspector was in the control room monitoring SRV testing at the time of the event. The resident inspectors are following the licensee's ongoing investigation.
The licensee has issued a press release regarding this event.
I h l This information is current as of 10:30 a.m. on July 13, 1992.
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- Region V received initial notification of this occurence by telephone s all f w % e Senio Resident at 1:50 p.m. on July 11, 199?.
ACT:
P. II. Johnson (510) 975-0300 K. E. Johnston (510)975-0354
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