ML20042C518

Updated LER 81-025/01X-1:on 810914,during Automatic Depressurization Sys Valve Operability Surveillance,B Electromatic Relief Valve Failed to Open at Rated Pressure. Caused by Excessive Leakage on Threads

ML20042C518
Person / Time
Site:	Dresden
Issue date:	02/25/1982
From:	Speroff R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20042C513	List: ML20042C512 ML20042C518
References
LER-81-025-01X, LER-81-25-1X, NUDOCS 8203310477
Download: ML20042C518 (3)

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, , , , , g ity, per T.S. 3.5.C., an immediate shutdown began at 2240 hrs. Minimal effect upon l

,,,,, , public health and safety because remaining ADS valves and low pressure ECCS systems were  ;

,9 ,,g operable, and Reactor was at less than 90 psig within the required 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Last simi- g lar occurrence reported by R.O. 50-249/80-21.

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ATTACHMENT TO LICENSEE EVENT REPORT 81-25/OlX-1 COMMONWEALTH EDISON COMPANY (CWE)

DRESDEN UNIT ILDRS-3 DOCKET # 050-249 On September 14, 1981, while under normal operation and performing the rated pressure portion of the operating surveillar.ce, DOS 250-5, (Automatic Blowdown System at Low Pressure and Rated Pressure), the 3-203-3B electro-matic relief valve failed to open. There were three unsuccessful attempts made by operating personnel to open the valve. -

Due to an earlier discovery of water in the HPCI steam supply line, the HPCI system was declared inoperable. As required by the Technical .

Specifications, Section 3.5.C., the operability surveillances were begun on the ECCS systems: ADS, Core Spray, LPCI and Isolation Condenser. Since the station was unable to meet the operational requirements of the ADS system, an orderly shutdown of the Unit 3 reactor commenced at 2240 hours0.0259 days <br />0.622 hours <br />0.0037 weeks <br />8.5232e-4 months <br />. The NRC was informed, and an unusual event was declared per the Dresden Generating Station F.mergency Plan. The GSEP unusual event was terminated, NRC informed, and the reactor was at less than 90 psig et 1015 hours0.0117 days <br />0.282 hours <br />0.00168 weeks <br />3.862075e-4 months <br /> on September 15, 1981.

There was minimal effect upon public health and safety because the remaining four ADS relief valves were operable, the low pressure ECCS systems were functional, and the reactor was at a pressure less than 90 psig within

. the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> time limit. In addition, the HPCI system could have been made available to perform its required function if necessary by clearing the outage on the system. Previously completed surveillances indicate that the HPCI system was operational and would perform its intended function.

The apparent cause of the failure wae excessive leakage on the threads between the cage and the disc retainer plug. During the course of the outage, the entire 3-203-3B electromatic relief valve was replaced with a spare valve that had the threaded area welded to prevent leakage. During startup, the operability surveillance was performed satisfactorily on 3B electromatic relief valve. To prevent future occurrences, the valve threads will be seal welded until a more acceptable alternative is found. The electromatic relief valve is a Dresser, Model Number 1525VX.

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81 - 52 PART I iTITLE OF EVE!iT OCCURRE 81 2223 Failure of 3B Electromatic Relief Valve to Open DATE TIME REASON FOR SUPPLEMEliTAL REPORT -

Up date cause of failure and corrective action 6

PART 2 l ACCEPTANCE BY' STATION REVIEW 5 3n%,w/ M Mj DATE 3N f %2_, ch'((

SUPPLEllENTAL REPORT APPROVED l' 644/4

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