ML19345G151
| ML19345G151 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 11/25/1975 |
| From: | Graves R CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | |
| References | |
| AO-50-213-75-4, NUDOCS 8103060828 | |
| Download: ML19345G151 (2) | |
Text
.C0kRECTEDCOPY i
ABNORMAL OCCURREf'CE REPORT Report Number:
50-213/75-4 (Erroneously numbered 50-213/75-3)
Report Date:
11/25/75 Occurrence Date:
11/18/75 facility _:
Connecticut Yankee Atomic Fower Company Haddam Neck Plant Identification of Occurrence:
Interrupted Service Water Supply To Containment Recirculation Fan Coolers Conditions Prior to Occurrence:
Steady state power; Operator conducting routine valving operation Description of Occurrence:
In accordance with Section 3.llD of the Connecticut Yankee Technical Specifications three of the four air recirculation units shall be operable whenever the reactor is critical. On November 18, 1975 during normal rounds an auxiliary operator found the "A" service water filter to be not operating properly and reported the problem to the Shift Supervisor.
The Shift Supervisor instructed the auxiliary operator to remove this equipment from service and to place the redundant piece of equipment
("B" service water filter) into service. The auxiliary operator observed that the "B" filter was turning and assumed it had been operating in parallel with the "A"
filter so he orocceded to isolate the "A" filter only, assuming that the "B" filter was already in service.
The operating shift was alerted to the problem when the containment Hi temperature and cooler low flow alarms were received.
The Shift Supervisor directed the auxiliary cperator to check tha valve lineup and the discharge valve was found closed.
The "B" filter had been on backwash and was turning, but was not in parallel operation as the auxiliary operator assumed.
The service wate'r was interrupted to all four containment recirculation fan coolers
.for a period of approximately 45 minutes thus rendering them not fully operable for this period of time.
Designation of Apparent Cause of Occurrence:
Operator error.
Analysis of Occurrence:
The loss of service water to all four containment recirculation fan coolers caused the cantainment recirculation fan coolers to be inoperable for containment temperature control during this period. Containment average temperature increased by 13 F and this presented no problem to normal operations. The fans and filter units were still operable but the entire recirculation fan cooler unit was not cperable due to the coolers be'ng without cooling water.
The results of accident analysis show that there is a substantial margin between the maximum pressure reached and the design pressure with all four fan cooler units lost and only one deluge pump operating. Also the conclusion of the hypothetical accident analysis shows that the limits of 10CFR100 would not be exceeded if all homo #
P00R ORIGINAL
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e ABriORMAL OCCURREtiCE REPORT 50-213/75-3
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Analysis of Occurrence (Continued) 4 filtration units were lost.
Corrective Action:
The operating department supervisor will issue an Operating Department Instruction (ODI) which will restate in writing a policy for lining up redundant equipment not in service. The policy will state that the inlet valve will be left open and the outlet valve vill be closed.
Also the importance and use of the shift passover sheet will be re-emphasized.
The operator will be reminded to perform a thorough check of valve lineups following even a routine valving operation.
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' A rm g Plant Superintendent
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