ML19351F678
| ML19351F678 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 04/19/1976 |
| From: | Crane P PACIFIC GAS & ELECTRIC CO. |
| To: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| IEB-76-02, IEB-76-03, IEB-76-2, NUDOCS 8102180099 | |
| Download: ML19351F678 (1) | |
Text
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y A A PACIFIC GA& AND ELECTR,IG C O M PANY I 't f '
I 77 BEALE STREET
- SAN F R A N C I S C O, C A l t F'O R N I A 9 410 6 * ( 41 $ ) 781 4211 somn C. MOR RI$$EY j'lj ;f,8;' ;,,,,,,,,
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April 19, 1976
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Mr. R. H. Engelken, Director Office of Inspection and Enforcement Region V l
U. S. Nuclear Regulatory Commission i
1990 N. California Boulevard Walnut Creek Plaza, suite 202 Walnut Creek, California 94596 Re:
Docket No. 50-133 License No. DPR-7
Dear Mr. Engelken:
In response to your letter dated March 17, 19'16 which en-closed I.E. Bulletins Nos. 76-02 and 76-03, we hereby inform you of the action we plan to take regarding HFA, HGA, HKA, HMA relay types made by G.E. prior to 1969 with nylon coil bobbins and G.E.
type STD relays which are in use in safety related systems.
There are no STD type relays installed or planned for use in safety related systems on Unit No. 3 at Humboldt Day.
There are many of the HFA, HGA, HKA, HMA types of relays in use in safety re-lated systems there, but none operate under the conditions which have caused coil failures as described in the G.E.
service letter.
The undesirable conditions are high relative humidity (greater than 60%),
direct current (DC) coil power, and intermittent operation.
All but three of the subject relays are alternating current (AC) coil power, all are located in the Unit No. 3 control room which is not generally subject to high humidity conditions, and all but nine of the subject relays de-energize to perform their safety function and these nine relays are AC coil power.
There have been no coil failures in any of the subje.ct relays.
In view of the operating conditions and operating record of the installed relays as discussed above, no immediate action is planned.
It is recognized that replacement of the nylon coil bobbins with Lexan l
coil bobbins is desirable, so the subject coils, or the entire relay as appropriate, will be replaced when the relays are routinely over-i hauled for preventive maintenance or worked on for other reasons.
ry truly you g
/
$002/$5
/
CC:
Office of Inspection and Enforcem t
l Division of Reactor Inspection Pr grams
(
U.
S. Nuclear Regulatory Commission Washington, D. C. 20555
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