ML16341C353
| ML16341C353 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/07/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7912200237 | |
| Download: ML16341C353 (10) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLAZA WALNUTCREEK, CALIFORNIA94596 December 7,
1979 Docket Nos.
50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:
ter. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
Enclosed is IE Bulletin No. 79-28 which requires action by you with regard to your power reactor facility(ies) 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, cC-R.
H. Engelken Director
Enclosures:
1.
List of Recently Issued IE Bulletins cc w/enclosures:
J. Worthington, PG&E W.
Raymond.
PG8E R.
- Ramsay, PGSE, Diablo Canyon
1 fr UNITLD STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 December 7,
1979 SSINS No.:
6820 Accession No.:
7910250505 IF. Bulletin No. 79-28 POSSIBLE MALFUNCTION OF NAMCO MODEL EA180 LIMIT SWITCHES AT ELEVATED TEMPERATURES Description of Circumstances:
The NRC has been recently advised through a
10 CFP. 21 report from NAMCO Controls that a malfunction of a NAMCO Model EA180 stem mounted limit switch (SflLS) occurred at the Cooper fluclear 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 manufacturer, the problem was traced to a batch of top cover 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 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 oroblem 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.
NAMCO recormends that any EA180 series switch with a date code between 02-79 through 08-79 should have its top cover qasket replaced.
Also, licensees should request 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 NAMCO 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 installed or plans to install flAMCO FA180 switches in any safety-related equinment located inside or outside containment, including valve position indicating circuitry related to containment isolation valves.
V
IF.'Bulletin No. 79-28 December 7,
1979 Page 2 of 2 2.
If such switches are identified, examine the four digit number stamped on the conduit boss of the switch housing.
If this number falls between OR-79 and 08-79, replace the top gasket of the switch in accordance with the manufacturer's recommendations provided in the enclosed letter.
3.
Submit your plans and programs, including schedules for corrective action, regarding your findings in response to Items 1 and 2 above.
4.
Provide the resoonse in writing within 30 days for facilities holding an operating license and within 60 days for those holders of construction permits.
Reports should be submitted to the Director of the appropriate NRC Regional Office and a copy should be forwarded to the U. S. Nuclear Regulatory Comnission, Office of Inspection and Fnforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
Approved by GAO, B180225 (R0072); clearance expires July 31, 1980.
Approval was given under a blanket clearance specifically for identified generic problems.
Attachment:
Fxtract of NAHCO Controls Letter dated 8/30/79
EXTRACT N A H C 0 CONTROLS August 30, 1979 Attention:
Subject:
Gentlemen:
Possible malfunction of Namco Model EA180 limit switches at elevated ambient temperatures Namco Controls has determined 'that the EA180 series limit switches shipped against your purchase order(s) b may h~ve top cover gaskets which will emit a resin vapor at temperatures above 175~ F.
This vapor could condense into deposits on the normally open contacts, possibly causing a swi tch malfunction.
We have reported this situation to the NRC, and we are contacting each customer who has received switches with gaskets from the questionable production lot, with the following recommendations:
a)
If the switches have not been put into service, and the ultimate ambient temperatures are
- unknown, the top cover gasket should be replaced.
b)
If the switches are in servi~e and are subjected to a continuous ambient temperature of more than 175 F, they should be inspected for deposits, the contacts cleaned if necessary, and have the top cover gasket replaced.
c)
If the switches are in service, (or scheduled for service) in a continuous ambient temperature of 175 F or less, no action is necessary.
We will provide you with whatever number of new top cover gaskets you may require, free of charge.
Or, if you prefer, we will accept switches returned to our Jefferson plant freight collect, for gasket replacement and/or cleaning.
We sincerely regret any inconvenience this remedy may cause.
If you have any questions, please contact either Robert H. Kantner, 216-268-4200 or John R.
Bendokaitis, 216-576-4070.
IE Bulletin No. 79-28 December 7,
1979 RECENTLY ISSUED IE BULLElINS Enclosure Bulletin No.
Subject Date Issued Issued To 79-27 79-26 Loss Of Non-Class-1-E Instrumentation and Control Power System Bus During Operation Boron Loss From BWR Control Blades 11/30/79 11/20/79 All power reactor facilities holding OLs and to those nearing licensing All B!AR power reactor facilities with an OL 79-25 Failures of ltestinghouse 11/2/79 BFD Relays In Safety-Related Systems All power reactor facilities with an OL or CP 79-17 (Rev.
1) 79-24 79-23 Pipe Cracks In Stagnant Borated Mater System At Pl!R Plants Frozen Lines Potential Failure of
'mergency Diesel Generator Field Exciter Transformer 10/29/79 9/27/79 9/12/79 All PMR's with an OL and for information to other Dower reactors All Dower reactor facilities which have either OLs or CPs and are in the late stage of construction
- All Power Reactor Facilities with an Operating License or a construction permit 79-14 Seismic Analyses For 9/7/79 (Suoplement 2)
As-Built Safety-Related Piping Systems All Power Peactor Facilities with an OL or a CP 79-22 Possible Leakage of Tubes 9/5/79 of Tritium Gas in Time-pieces for Luminosity To Fach Licensee who Receives Tubes of Tritium Gas Used in Timepieces for Luminosity 79-13 (Rev.
1)
Cracking in Feedwater System Piping 79-02 Pipe Support Base Plate (Rev.
1)
Designs Using Concrete (Supplement 1)
Expansion Anchor Bolts 8/30/79 8/20/79 All Designated Applicants for OLs All power Reactor Facilities with an OL or a CP
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