ML19256F691
| ML19256F691 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 12/10/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Hines E DETROIT EDISON CO. |
| References | |
| NUDOCS 7912200115 | |
| Download: ML19256F691 (1) | |
Text
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UNITED STATES 8 " ',,, ( '[,,n NUCLEAR REGULATORY COMMISSION E
REGION 111
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799 ROOSEVELT ROAD 0
i-o GLEN ELLYN,ILLINols 60137 Docket No. 50-341 DEC1C1979 The Detroit Edison Company ATTN:
Mr. Edward Hines, Assistant Vice President and Manager Quality Assurance 2000 Second Avenue Detroit, MI 48226 Gentlemen:
Enclosed is IE Bulletin No. 79-28 which requires action by you with regard to your power reactor facility with an operating license or a construction permit.
Should you have questions regarding this Bulletin or the actions required of you, please contact this office.
Sincerely, A&
James G. Keppfer Director
Enclosure:
IE Bulletin No. 79-28 cc w/ encl:
Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commission Eugene B. Thomas, Jr.,
Attorney 1775 039 7 912200 lI N
UNITED STATES SSINS No.: 6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250505 WASHINGTON, D.C.
20555 December 7, 1979 IE Bulletin No. 79-28 POSSIBLE MALFUNCTION OF NAMC0 MODEL EA180 LIMIT SWITCHES AT ELEVATED TEMPERATURES Description of Circumstances:
The NRC has been recently advised through a 10 CFR 21 report from NAMC0 Controls that a malfunction of a NAMC0 Model EA180 stem mounted limit switch (SMLS) occurred at the Cooper Nuclear Station.
Investigation into the switch failure by the licensee revealed yellow and brown " crystal-like" resin deposits on the internal components of the switch. The affected switch is located inside the drywell containment at this facility and was being used as the replacement switch for an unqualified SMLS previously identified in IE Bulletin Nos.
78-04 and 79-01.
According to the nanufacturer the problem was traced to a batch of top cover gaskets of which s ne were over-impregnated and insufficiently heat cured.
It has been determined that this condition can leave an uncured residue of " Loctite" in the gasket, which vaporizes at sustained temperatures above 175 F.
To correct the problem, the manufacturer has revised production techniques beginning September 1979 in order to better control the impregnation process and to properly heat cure the gaskets following impregnation.
This problem is unique to all NAMC0 Model EA180 series switches received by licensees after March 1, 1979.
According to the manufacturer, the suspect switches can be identified by checking the date code which is a 4 digit number st:mped on the conduit boss of the switch housing.
NAMCO recommends that any EA180 series switch with a date code between 02-79 through 08-79 should have its top cover gasket replaced.
Also, licensees should raquest from their suppliers of equipment on which NAMCO EA180 series switches are used that they check their inventory and replace top cover gaskets on switches date coded between 02-79 through 08-79.
The enclosed letter from NAMC0 further describes the high-temperature environ-mental problem with the top cover gaskets used in their EA180 switches and provides recommendations to correct the problem.
According to NAMCO, this letter has been sent to each customer who was shipped EA180 switches between February 21, 1979, and August 24, 1979.
Action to be Taken by Licensees of Power Reactor Operating Facilities and Holders of Construction Permits:
1.
Determine if your facility has ins switches in any safety related equi DUPLICATE DOCUMENT containment, including valve positi containment isolation valves.
Entire document previously entered into system under:
ANO 1773 040 a
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