ML19257A727

LER 79-037/03L-0:on 791116,diesel Generator Starting Air Supply Valves 1/2-4699-121 Locked in Closed Position.Caused by Operator Error.Generator Not Rendered Inoperable Due to Redundant Valve.Valve Opened & Locked

ML19257A727
Person / Time
Site:	Quad Cities
Issue date:	12/11/1979
From:	Wykoff D COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19257A724	List: ML19257A723 ML19257A727
References
LER-79-037-03L-01, LER-79-37-3L-1, NUDOCS 8001070473
Download: ML19257A727 (2)

Text

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LICENSEE EVENT REPORT

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CdNTRUL BLOCK: l l l l l l l (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 1 6 ITITl8 l9i l t lLICENSEE 7

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7 8 60 61 DOCK ET NUVS E R 68 69 EVENT DATE 75 REPORT DATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h '

O 2 l On November 16, 1979 one of the two Unit 1/2 diesel aenerator startino air supply l g; valves (1/2-4699-121) was found in the locked closed position. Valve 1/2-4699-121 is l-

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I T T i' l one of two starting air isolation valves which supply air to the diesel starting l o 3 l motocs. Because each diesel generator is designed with two separate starting air l g[ systems,-this event did not render the Unit 1/2 diesel generator inoperable.

O 7 l l o a i I 7 8 9 80 SYSTEM CAUSE CAUSE COMP. VALVE CODE COOE SU8 CODE COMPONENT CODE SUSCODE SUBCODE 7

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44 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i Ol The 1/2-4699-121 valve was not properly returned to service followina an October 31, I ii li; ! 1979 maintenance outage. The 1/2-4699-121 valve was immediately opened and locked. I

, , l The importance of properly returning a system to service was reinstructed to the l l

equipment operators. The Unit One and Unit Two diesel generator starting air l 3 , g isolation valves were also verified for proper line up. l 7 8 9 80 STA S  % POWE R OTHERSTATUS 015 0 RY DISCOVERY DESCRIPTION 1 5 l El@ l 0 l 7 l 5 l@l NA l lA]@l 00erational Event l ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE 1 6 l Zl @ l Z l g l NA l l NA I 7 8 9 10 11 44 45 80 PERSONNEL EXPO 3URES NUMBER TYPE DESCairTION -

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l;;;;;;;;;;;l; 7 8 3 to 68 69 3Ja E NAME OF PREPARER PHONE: 309-654-2241 ext. 180 f,

l. LER NUMBER: LER/R0 79-37/03L-0 ll. LICENSEE NAME: Commonwealth Edison Company Quad-Cities Nuclear Power Station Ill. FACILITY NAME: Unit One IV. DOCKET NUMBER: 050-254 V. EVENT DESCRIPTION: -

On November 16, 1979 one of the two Unit 1/2 diesel generator starting air supply valves (1/2-4699-121) was found in the locked closed position. The 1/2-4699-121 valve is one of two starting air isolation valves which supply a common air header to the diesel air starting motors. On each diesel generator there are two 100% capacity air starting systems. Closure of the 1/2-4699-121 valve subsequently did not render the Unit 1/2 diesel generator inoperable. The diesel starting air isolation valves are normally locked open valves which are closed only when the diesel is taken out of service for maintenance.

The Unit 1/2 diesel generator was last taken out of service on October 31, 1979 to resolve a problem concerning the governor and fuel filters. (R0 79-33/03L).

VI. PROBABLE CONSEQUENCES OF THE OCCURRENCE:

Although this event took away the redundancy designed in the starting of the Unit 1/2 diesel, safe reactor operation was still maintained. The redundant starting air supply system was available to start the Unit 1/2 diesel generator had the need arose. In addition the Unit 1/2 diesel generator was demonstrated to be operable after the maintenance performed on October 31, 1979, and again during surveillance testing on November 9, 1979 Vll. CAUSE:

THe cause of this occurrance was personnel error. The 1/2-4699-121 valve was not re-opened following the performance of maintenance on the Unit 1/2 diesel generator.

Vill. CORRECTIVE ACTION:

The 1/2-4699-121 valve was immediately opened and locked. All other diesel generator starting air supply valves were checked to verify that they were locked open. It was stressed to the equipment operators to make sure that any valve whose position has been changed for maintenance must be returned to its required position following the completion of maintenance.

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