ML18136A305
| ML18136A305 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 12/07/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Proffitt W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 7912200070 | |
| Download: ML18136A305 (6) | |
Text
In Reply Refer To:
RII:JPO 50-338, 50-339 50-404, 50-405 69:280, so-UD UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA ST., N*.w., SUITE 3100 ATLANTA, GEORGIA 30303 DEC 7 1979 Virginia Electric and Power Company Attn:
W. L. Proffitt Senior Vice President, Power P. 0. Box 26666 Richmond, Virginia Gentlemen:
23261 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.
Enclosures:
- 1.
IE Bulletin No. 79-28 w/its Attachment
- 2.
List of Recently Issued IE Bulletins Sincerely, James P. O'Reilly Director 7 912200070
Virginia Electric and Power Company cc w/encl:
W.R. Cartwright, Station Manager Post Office Box 402 Mineral, Virginia 23117 P. G. Perry Senior Resident Engineer Post Office Box 38 Mineral, Virginia 23117 W. L. Stewart, Manager Post Office Box 315 Surry, Virginia 23883 DEC 7 1979 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 December 7, 1979 SSINS No.: 6820 Accession No.:
7910250505 IE 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 CFR 21 report from Namco 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 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 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.
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 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 Namco EA180 switches in any safety-related equipment located inside or outside containment, including valve position indicating circuitry related to containment isolation valves.
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 02-79 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 response 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 Commission, Office of Inspection and Enforcement, Division of Reactor Operations Inspection, Washington, D.C.
20555.
Approved by GAO, Bl80225 (R0072); clearance expires July 31, 1980.
Approval was given under a blanket clearance specifically for identified generic problems.
Attachment:
Extract of Namco Controls Letter dated 8/30/79 j
Attention:
Subject:
Gentlemen:
EXTRACT e
N A M C O C O N T R O L S August 30, 1979 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) #
may have 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 switch 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 service 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 Bulletin No.
79-28 79-27 79-26 79-25 79-17 (Rev. 1) 79-24 79-23 79-14 (Supplement 79-22 79-13 (Rev. 1)
- 2)
RECENTLY ISSUED IE BULLETINS Subject Possible Malfunction of Namco Model EA180 Limit Switthes at Elevated Temperatures Date Issued 12/07/79 Loss Of Non-Class-1-E 11/30/79 Instrumentation and Control Power System Bus During Operation Boron Loss From BWR 11/20/79 Control Blades Failures of Westinghouse 11/2/79 BFD Relays In Safety-Related Systems Pipe Cracks In Stagnant 10/29/79 Borated Water System At PWR Plants Frozen Lines 9/27/79 Potential Failure of Emergency Diesel Generator Field Exciter Transformer Seismic Analyses For As-Built Safety-Related Piping Systems Possible Leakage of Tubes of Tritium Gas in Time-pieces for Luminosity Cracking in Feedwater System Piping 9/12/79 9/7 /79 9/5/79 8/30/79 Enclosure Issued To All power reactor facilities holding OL or CP All power reactor facilities holding OLs and to those nearing licensing All BWR power reactor facilities with an OL All power reactor facilities with an OL or CP All PWR's with an OL and for information to other power reactors All power 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 All Power Reactor Facilities with an OL or a CP To Each Licensee who Receives Tubes of Tritium Gas Used in Timepieces for Luminosity All Designated Applicants for OLs