ML20003C389
| ML20003C389 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 03/25/1974 |
| From: | JERSEY CENTRAL POWER & LIGHT CO. |
| To: | |
| References | |
| AO-50-219-74-23, NUDOCS 8103030284 | |
| Download: ML20003C389 (3) | |
Text
.
Renulatery Ede Cy.
l OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/23 77 Report Date
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.. a March 25, 1974
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Occurrence Date
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March 15, 1974 v
Identification of Occurrence Vioistion of the Technical Specifications, paragraph 3.1. A.3, the high flow isolation set point for the isolation condenser condensate line break sensors were found to actuate at differential pressures in excess of those as stated in Technic 1 Specification Table 3.1.1.H.2 (127 inches AP H 0).
This event 2
is considered to be an abnormal occurrence as defined in the Technical Specifi-cations, paragraph 1.15A.
Conditions Prior to Occurrence The plant was operating at steady-state power.
'Ihe major plant parameters at the time of the occurrence were as follows:
Power:
Reactor, 1902 MWt Electric, 661 NKe 4
Flow:
Recirculation, 15.3 x 10 gpm 6
Feedwater, 7.10 x 10 lb/hr Reactor Pressure:
1020 psig Stack Gas:
40,600 pCi/sec Description of Occurrence On Friday, March 15,1974, at 1852, while performing routine surv'eillance testing on the isolation condenser condensate high flow line break sensors, it was observed that two of the four sensors (located two each on the A and B isolation condensers) actuated at set points above the Technical Specification limit of 27 inches H 0.
The two sensors, IB11A2 and IB11B2, were both found 2
to actuate at 29 inches of H O differential pressure. The complete condensate 2
line break sensor surveillance results were as follows:
4 7/A3o2od
Abnormal Occurrence No. 50-219/74/23 Page 2 Isolation Condenser "A" Trip Reset Sensor (Inches H 0)
(Inches H O) 2 2
IB11A1 26.5 23 IB11A2 29.5 25 Isolation Condenser "B" Trip Reset Sensor (Inches H 0)
(Inches H O) 2 2
1B11B1 27 25.5 IB11B2 29 26.5 The-IB11A2 and IB11B2 sensors were recalibrated and were surveilled to function in the proper manner. The surveillance retest results were as follows:
Isolation Condenser "A" Trip Reset Sensor (Inches H O)
(Inches H 0) 2 2
IBilA2 27 23 i
Isolation Condenser "B" Trip Sensor (Inches H O)
(Inches H 0) 2 2
IB11B2 26.5 24.5 Apparent Cause of Occurrence The cause of the occurrence has been attributed to the lack of sensor repeatability.
Analysis of Occurrence The safety significance of this event lies in the inability of the redundant sensors to perform at the Technical Specification limit set point.
Had a condition occurred whereby the condenser would have been required to
_ isolate, the redundant sensors, IB11A1 and 1B11B1, would have performed the isolation function in the proper manner.
I
Abnormal Occurrence No. 50-219/74/23 Page 3 Corrective Action After an evaluation of the November 14, 1972 isolation condenser test data, it has been concluded that changing the trip set point of the isolation condenser condensate high flow line break sensors from the Technical Specifi-cations limit of 27 inches of water to 24 inches of water and the trip set point of isolation condenser steam high flow line break sensors from 20 psig to 15 psig will not adversely affect the isolation function of these sensors under transient conditions. The appropriate procedures are now being revised in preparation for implementing these set point changes.
Actual implementation will take place by March 27, 1974.
It is expected that these changes will help avoid creating abnormal occurrences as a result of the lack of sensor repeatability.
Failure Data Type:
Barton Differential Pressure Switch Range:
0-60 inches H O 2
Pressure Rating:
1500 psig Serial Nos.:
IB11A2 - 278-965 IB11B2 - 278967
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