ML20125E310

R0 2-80-1/1P:on 800103,drywell Ventilation Isolation Valve Was Fully Open at Time When Valve Should Have Been Limited to 37 Degree Opening.Caused by Lack of Proper Control to Maintain Valve at Less than 37 Degree Opening

ML20125E310
Person / Time
Site:	Peach Bottom
Issue date:	01/03/1980
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
References
RO-2-80-01-1P, RO-2-80-1-1P, NUDOCS 8002060628
Download: ML20125E310 (2)

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Pil( t,ADEI, Pill A fil.CCTRIC C&F ANY / l Peach Bottom Atomic Power Star ton k Delta, Pennsylvanin 17314 1

%@ . January 3, 1980 l

Mr. Boyce 11. Grier Office of Inspection and Enforcement l Region 1 United States Nuclear Regulatory Commission l 631 Park Avenue King of Pruss Ln, PA 19406 l SUBJECr: REPORTAllLU OCCURRENCE - PROMPT NOTIFICATION l

Confirming W. T. Ullrich's crmversntion with Mr. Greenman, Region L. United States Nuclear Regulatory Cummi ssion on 1/3/80.

Re ference : Docket No. 050-277/278 Peach Rottom Units 2 and 3 Technical Specification

Reference:

6.9.2a(6) 10 Report No. 2-79-1/IP Occurrence Date: January 3,1980 t

Identification of Occurrence:

l Review of operation found that a drywell ventilation isointion valve had I been allowed to f%tily open at a time when the valve should have been limited to an opening of 370 Conditions Prior to Occurrence:

l l Unit 2 operating at approximately 92% power. Unit 3 operating at full power.

Apparent Cause of Occurrence:

Lack of proper control to ensure that drywell ventilation isolation valves are maintained at less than 374 open during renctor operation, Analysis of Occurrence:

As identified in a previous LER (2-79-11/IP), t he drywell ventilation isolation valves cannot be assured of closing a6minst 1.oCA pressure if they are open more than 370 . While de-inerting the drywell in preparation for a pisoned shutdown of Unit 2, the air nupply pressure t o A0-25218 was raised to a pressure which opened the valve more than 370 Corrective Action:

1he occurrence was identified approximately R hours after the occurrence, and the opening of the valve was immediately reduced to less than 37". Informat!on tags stating the correct pressure have now been placed on the air supply regulator for each drywell ventilation isolation val.ve on Unit 2 and Unit 3.

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2-79-11/IP 77*NAd W. T. Ullrich Station Superintendent m : cat i

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