ML20211J731
| ML20211J731 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/02/1986 |
| From: | Tucker H DUKE POWER CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8611110240 | |
| Download: ML20211J731 (2) | |
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DUKE POWER GOMPm P.O. HOX 33180 CIIAHLOTTE, N.O. 28242 HALD. TUCKER TELEPHONE mm PRESEDFFF (704) 373-4531 wtuman Paomortion a ) d9gg u6 July 2, 1986 1
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er dDr.:-J.- Waleen Grace,3 Regional Administrator U.S. Nuclear Regulatory Connaission Region II 101 Marietta St. NW, Suite 2900
-Atlanta, Georgia 30323 Re: Catawba Nuclear Station,- Unit 2 Docket No. 50-414 [
Dear Dr. Grace:
Pursuantato3 Technical:sSpecificationr3.4.9.3, Action Statement c, please find gttached;a Spesial; Report concerning the automatic opening of a pressurizer power-operated relief valve.
Very truly yours, Hal B. Tucker RWO/ll/jgm 4
Attachment xc: Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 NRC Resident Inspector Catawba Nuclear Station V
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r SPECIAL REPORT LIFTED VALVE 2NC34 (NC PORV)
Circumstances Initiating The Transient:
I On June -2,1986 during performance of controlling procedure for unit shutdown _(OP/2/A/6100/02), step 2.61 placed valves 2NC-32 and 2NC-34
.(pressurizer PORV's) in the low pressure (L/P) mode. This reduced.the lift j
i setpoint of the PORV's to 400 psig. 2NC-32 was placed in the L/P mode i
without incident. When 2NC-34 was placed in the L/P mode, it insiediately lifted. The Operator at the controls immediately closed 2NC-34 by placing 7
i the valve in the " normal" mode. Pressure gauges being used during depressurization ranged in values from 380 to 360 psig.. Computer indication for B loop was 379 psig. Further depressurization commenced and 2NC-34 was again placed in L/P mode. Again the PORY lifted, so it was returned to z
" normal" mode. On the third attempt, with Reactor Coolant Syster. pressure at 320 psig, 2NC-34 was placed in L/P mode without incident.
Effect of PORV On The Transient:
No real transient existed for the PORV to mitigate. Reactor Coolant pressure was lowered to 320 psig and the PORY no longer lifted.
Corrective Action To Prevent Recurrence:
The valve's controlling circuit was thoroughly checked out and no problems were identified. The valve lifted at the correct pressures in the L/P mode.
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