PNO-II-93-037, on 930820,unscheduled Shutdown in Excess of 72 H Occurred Due to Need to Repair Leak in Joint on SG B. RCS Temp Reduced Below 200 Degrees F.Licensee to Inspect Drain Valve Assemblies on Sg.State of VA Notified
| ML20056F933 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 08/23/1993 |
| From: | Belisle G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| References | |
| PNO-II-93-037, PNO-II-93-37, NUDOCS 9309010041 | |
| Download: ML20056F933 (2) | |
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~ August 23, 1993 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-II-93-037 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region II staff on this date.
j Facility Licensee Emercency Classification Virginia Power Co.
Notification of Unusual Event Surry 1 Alert Surry, Virginia Site Area Emergency Dockets: 50-280 General Emergency X Not Applicable
Subject:
UNSCHEDULED SHUTDOWN IN EXCESS OF 72-HOURS At 9:00 p.m.
on August 20, 1993, a normal shutdown of Unit 1 fron 100%
power was commenced to repair a leak that appeared to be coming from a mechanical joint on the
'B' steam generator (SG) primary side manway cover. The leak was first noted on June 26, 1993 by an increase in containment radiation monitor readings. The leak was subsequently classified as a 0.2 gpm identified leak.
Since the leak identification, the licensee had monitored the leak with closed circuit TV. A slight increase in leakage was noted by the closed circuit TV monitor on August 15 and preparations to shut down the unit were initiated.
After Unit 1 was taken to hot shutdown on August 21, 1993, and radiation levels reduced, a closer visual inspection of the leakage indicated that it was ccming from a non-isolable leak in a 3/4 inch weld joint on the SG channel head drain valve assembly. This drain valve assembly is in close proximity to the SG manway and the leakage was directed up towards the manway and deflected out of the insulation seams.
At 4:43 a.m.,
on August 21, 1993, the licensee declared a Notification of Unusual Events (NOUE) based on non-isolable Reactor Coolant System (RCS) pressure barrier leakage. Technical Specification 3.1.C.4 required the unit be brought to cold shutdown condition. The NOUE was terminated at 2:43 a.m.
on August 22, 1993 after RCS temperature was reduced below 200 degrees Fahrenheit. A small amount (a few drops) of leakage continued as the licensee proceeded with closing the loop stop valves and draining of the loop for repairs. Reduced inventory is currently not scheduled. The licensee is planning to inspect the drain valve assemblies on the other two SGs.
Shutdown for the RCS leakage repairs and other minor maintenance is anticipated to last approximately 12 days.
The resident inspectors are following the shutdown and repair activities.
The State of Virginia was informed.
Initial notification of the decision to shut down Unit I was provided to the resident inspector and the Region II's Director of Reactor Projects by the Station Manager and the Vice President of Nuclear Operations on August 18, 1993. This information is current as of 10:00 a.m.,
on 9309010041 930823
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August 23, 1993.
Contact:
G. A.
BELISLE (404)331-4196 i
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