ML19256F686
| ML19256F686 | |
| Person / Time | |
|---|---|
| Site: | Zimmer |
| Issue date: | 12/10/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Borgmann E CINCINNATI GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7912200099 | |
| Download: ML19256F686 (1) | |
Text
{
e en arcoq'o, UNITED STATES
+
8
P,n NUCLEAR REGULATORY COMMISSION
}
{
.,E REGION lli 799 ROOSEVELT ROAD o,
g b
GLEN ELLYN, ILLINOIS 60137 o
Docket No. 50-358 DEC 101979 Cincinnati Gas and Electric Company ATTN:
Mr. Earl A. Borgmann Senior Vice President Engineering Services and Electric Production 139 East 4th Street Cincinnati, OH 45201 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, 1 M*
na--
JamesG.Keffer Director
Enclosure:
IE Bulletin No. 79-28 cc w/ enc 1:
Mr. J. R. Schott, Plant Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Harold W. Kohn, Power Siting Commission Citizens Against a Radioactive Environment Helen W. Evans, State of Ohio 1775~049 ~
7 012200 0 9 9
UNITED STATES SSINS No.: 6820 NUCLEAR REGULATORY COMMISSION Accession No.:
0FFICE 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 NAMCO 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 insida 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.
Accordingtothemanufacturer)theproblemwastracedtoabatchoftopcover gaskets of which some 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 vaporiles 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 NAMCO 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 stamped on the conduit boss of the switch housing.
NAMC0 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 request from their suppliers of equipment on which NAMC0 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 apd Holders of Construction Permits:
1775 030 1.
Determine if your facility has i switches in any safety-related e containment, including valve pos1 DUPLICATE DOCUMENT containment isolation valves.
Entire document previously entered into system under:
ANO No. of Pages: