ML19345G103
| ML19345G103 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 03/26/1975 |
| From: | Crane P PACIFIC GAS & ELECTRIC CO. |
| To: | Goller K Office of Nuclear Reactor Regulation |
| References | |
| 3457, AO-DPR-7-75-1, NUDOCS 8103020379 | |
| Download: ML19345G103 (2) | |
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PACIFIC GAS AND E LE C T RIC C F)M PANY FOW3 l
77 B E ALE S T R E ET. S A N F R A N CISCO, C A LIFO R NI A 94106 (415) 781-4211 I *II
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Docket No. 50-133 -
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License No. DPR-7 Humboldt Bay Power Plant Unit No. 3 s
Dear Mr. Goller:
This report is submitted in accordance with Section IX.H.2.
- a. (4) of the Technical Specifications of License No. DPR-7.
Notifica-tion of this occurrence was made via telephone to Mr. R. T. Dodds of the Region V Office of Inspection and Enforcement on March 17, 1975, the day of the occurrence.
This notification was confirmed by tele-copier on March 18, 1975.
Abnormal Occurrence Reoort Number:
DPR-7/75-1 Report Date:
March 26, 1975 l
l Occurrence Date:
March 17, 1975 1
Facilit_y:
Humboldt Bay Power Plant Unit No. 3 Eureka, California Identification:
The d-c motor operated emergency condenser condensate return valve did not respond to a remote signal to open during the performance of a routine test.
At the time of the occurrence, the reactor was operating at 193 MNt.
==
Description:==
On March 17, the routine test of the drywell automatically initiated motor. operated isolation valve, required by i
Table IX-1 of the Technical Specifications, revealed that the emergency condenser condensate return valve could not be operated from the control room.
An operator was imnediately dispatched to open the valve manually.
The valve was then closed electrically from the control room and the valve f/030303'Y5 P00R ORIGINAL.=
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Mr. Earl R. Goller 2
March 26, 1975 test was then conducted satisfactorily.
Approximately ten hours after this occurrence the valve was again tested and operated successfully in all respects.
Designation of Apparent Cause:
An inspection did not reveal any ap-parent condition which could cause the valve to stick shut.
The motor operator torque switch was checked and found to be set properly.
The motor running current was checked and found to be satisfactory.
The valve had been exercised satisfactorily following the last Unit startup on February ll, 1975.
Analysis:
If an isolation trip had occurred, the reactor safety valves would have operated to limit the reactor pressure transient and to remove decay heat.
The emergency condenser would then have been manually initiated in order to remove decay heat.
Since only the open-ing operation was affected, the valve would have closed automatically when required (on high refueling building pressure) if it had been previously opened.
There are no other motor operated valves at the plant that use the same operator.
Therefore, this malfunction has no safety implications other than these analyzed above.
Corrective Action:
A testing program has been initiated to reduce the probability of the incident recurring.
The valve will be exercised daily for at least one week.
At the end of this period, the frequency of testing will be evaluated and reduced to weekly if the results are satisfactory.
Routine monthly testing will be resumed when the results of the weekly tests are satisfactory.
Very truly yours, Ak kW)
CC:
Mr. R. H. Engelken, Director Office of Inspection and Enforcement Region V P00R ORIGINAL
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