ML20209G078

Part 21 Rept Re Possible Defect in Namco Contact Lever Assembly Part EA188-30007 for Series EA180 Limit Switches. Program Will Be Initiated to Determine If Cracks Caused Switch Failure

ML20209G078
Person / Time
Site:	Nine Mile Point
Issue date:	07/14/1986
From:	Swanson N NAMCO CONTROLS
To:	Zech G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
Shared Package
ML20209F986	List: ML20209F980 ML20209G078
References
REF-PT21-87 NUDOCS 8704300465
Download: ML20209G078 (2)

Text

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E MER W W Because e othong else works better.

July 14, 1986 Corrected Copy Mr. Gary Zech Chief - Vendor Program 1

U.S. Nuclear Regulator Commission Washington, D.C. 20555

Subject:

Notification of a possible product defect as required by 10CFR21.

Namco part #EA188-30007 Contact Lever i

Assembly for Series EA180 Limit Switches

Dear Mr. Zech:

We have been advised by Stone & Webster Engineering Corporation that their

, inspectors - at Niagara Mohawk's Nine Mlle Point have found cracks in plastic contact lever arms in 14 qualified Namco EA180 limit switches. We have ob-tained samples of these parts from the plant, and examined them on July 11, 1986. (See a copy of our drawing enclosed.)

The parts returned to us were taken from switches manufactured in 1979, accord-ing to the date code on the exterior of the switch housing. This is the first report of this condition that we have received from a field installation, and our records show that we have shi' p ped over 40,000 EA180 switches in the last 10 years.

Inasmuch as we do not know whether the cracked condition could lead to fracture and subsequent switch failure, we are proceeding as follows:

l. Proposing to Niagara Mohawk that they replace cracked contact lever arms in all Category I safety-related limit switches with new lever arms, which we will provide.

2. Initiating a test program of switches with cracked lever arms

returned from Nine Mile Point to . determine if the cracks even-l tually cause switch failure, and if so, after how many normal operations.

'3. Reviewing the specified plastic materials and production pro-cesses involved with these lever arms, to insure that the con-dition does not recur.

gass W41 S

AN ACW CLEWL ANO CHNw

. o NAuco ccWmor_s U. S. Nuclear Regulatory Commission July 14, 1986 Pending the outcome of our life e.esting in #2 above, we will advise the NRC and our utility customers what action we recommend be taken to insure that this problem is properly corrected, if corrective action is required.

Verv truly yours, tsis w N. E. Swanson President NAMCO CONTROLS NES/kg Attach.

cc: E. L. Laskowski E. L. Roob C. E. Crocker, Stone & Webster Engrg. Corp.

Nine Mile Pt. #2 P.O. Box 63 Lycoming, NY 13093 l

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