ML20084K320
| ML20084K320 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 07/18/1974 |
| From: | COMMONWEALTH EDISON CO. |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084K292 | List: |
| References | |
| AO-50-254-74-8I, NUDOCS 8305190275 | |
| Download: ML20084K320 (2) | |
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REPORT NUMBER: A0 254/74-81 REPORT DATE: July 18, 1974 OCCURRENCE DATE: July 9, 1974 FACILITY: Quad-Cities Nuclear Power Station Cordova, Illinois 61242 l
lDENTIFICATION OF OCCURRENCE:
l Excessive leakage on cleanup Isolation valve M0-1-1201-5.
CONDITIONS PRIOR TO OCCURRENCE:
Reactor in cold shutdown condition for refueling outage, reactor water cleanup system out of service, and piping drained.
I DESCRIPTION OF OCCURRENCE:
Local leak rate testing of the Unit One primary containment clean-Up System valves was in progress on July 9,1974. Valves M0-1-1201-2 and M0-1-1201-5 were placed in the closed position by actuating the control room switc i
The leak rate test was performed by pressurizing the volume between the valves l
through the pressure test valves 1-1201-120 and 1-1201-121 to a pressure of 68 psig to overcome the static head of water on the reactor side of the M0-1-1201-2
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valve. The leak rate was in excess of the limit of 18.36 SCFH (5% L o) for any t
(
primary) containment isolation valve as given by Technical Specification 4.7.A.2.
i.(2)(b.
The 1201-5 was taken out of service and repairs were performed.
A subsequent leak test was performed at an elevated pressure to overcome the reactor static head and the leakage was found to be reduced to below the maximum of 18.36 SCFH as required by Technical Specification 4.7.A.2.1.(2)(b).
DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:
The excessive leakage is attributed to cuts found on the valve gate.
ANALYSIS OF OCCURRENCE:
Al though the leakage of the M0-1-1201-5 valve was in excess of Technical specifi-cation limitations, the consequences of the failure of this valve are minimized by the fact that the MO-1-1201-2 did not fall. Since the operation of the 1201-5 valve does not effect the operation of the 1201-2 valve, the 1201-2 valve would have performed its isolation function during en accident situation. Since this would have isolated the reactor and the reactor would not have lost its water i
inventory, the only additional water that could have escaped to the environment l
0305190275 740718 DR ADOCK 05000254 PDR
A0 254/74-81 July 18.1974 was the 4.80 ft of water that could have been trapped between the 1201-2 and 1201-5 valves. This water would have been reactor water.
Because this piping is contained in the Clean-Up Regenerative heat exchanger room, the consequences to public health and safety and personnel exposure are minimal.
CORRECTIVE ACTION:
The valve gate was relapped and reinstalled.
FAILURE DATA:
This is the first time the valve has been tested since the initial pre-operational leak test.
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