05000254/LER-1979-037-03, /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

/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: 05000254/LER-1979-037, Forwards LER 79-037/03L-0 05000254/LER-1979-037-03, /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
References
LER-79-037-03L-01, LER-79-37-3L-1, NUDOCS 8001070473
Download: ML19257A727 (2)

LER-1979-037, /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

Event date:
Report date:
2541979037R03 - NRC Website

text

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LICENSEE EVENT REPORT

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7 8 9 LICENSEE CODE 14 15 LICENSE NUMetri 25 26 LsCENSE TYPE J0 57 CAT 68 CON'T 3g,% l L l@ 0 l 510 l0 l0 l2 l5 l 4 l@l 1 l 1 l 1 l 6 l 7 l 9 l@ll 12 11 Il 17 lo l@

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60 61 DOCK ET NUVS E R 68 69 EVENT DATE 74 75 REPORT DATE 80 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

motocs.

Because each diesel generator is designed with two separate starting air l

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systems,-this event did not render the Unit 1/2 diesel generator inoperable.

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7 8 9 80 SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE COOE SU8 CODE COMPONENT CODE SUSCODE SUBCODE l El El g l Al g l Bl g {Z lZ lZ lZ l Zl Zl g lZ [ g g g O

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10 11 12 13 18 19 20 SEQUE NTI AL OCCURRENCE RSPORT REvlSION LE R/RO EVENT YE AR REPORT NO.

CODE TYPE N O.

@ REPORT l 7l 9l l_l l0l3 7l lpl l0 l3 l lL l l_l 0l 21 22 23 24 26 27 26 29 30 31 32 TKN A ON O PLANT U

HOURS 22 58 IT E PhR 8.

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3b 36 37 40 41 42 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i O l The 1/2-4699-121 valve was not properly returned to service followina an October 31, I

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1979 maintenance outage. The 1/2-4699-121 valve was immediately opened and locked.

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

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equipment operators. The Unit One and Unit Two diesel generator starting air l

g isolation valves were also verified for proper line up.

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7 8 9 80 STA S

% POWE R OTHERSTATUS 015 0 RY DISCOVERY DESCRIPTION l El@ l 0 l 7 l 5 l@l NA l

lA]@l 00erational Event l

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ACTIVITY CO TENT RELEASED OF RELEASE AMOUNT OF ACTIVITY LOCATION OF RELEASE l Zl @ l Z l g l NA l

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7 8 9 10 11 44 45 80 PERSONNEL EXPO 3URES NUMBER TYPE DESCairTION -

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PEnSONNE L INJLRIES OESCRiPTiONh Nuv8ER l0l0l0l@l NA jgOl 7En l

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'dU 33 LOSS OF OR DAVACE TO FAC;LITY Q TYPE DE SCRIPTION

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8 3 10 80 PUB LICITY NRC USE ONLY N)) 0 (QQQ ISSUED

DESCRIPTION

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8 3 to 68 69 3Ja E 309-654-2241 ext. 180 f,

NAME OF PREPARER PHONE:

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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.

1693 359