ML20207G953

Corrected Part 21 Rept Re Cracks in Plastic Contact Lever Assembly EA188-30007 in Series EA180 Limit Switches. Replacement of Contact Lever Arms in All Category I safety-related Limit Switches Proposed.Tests Initiated

ML20207G953
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
ML20207G948	List: ML20207G943 ML20207G953
References
REF-PT21-86 NUDOCS 8607230262
Download: ML20207G953 (2)

Text

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Namco Conttis 7567 Tylu Boulevnd Mentor, Ohio 44060 (216) 946-9900 g g g g gg e Telex 24-1566 seca,se nouung wse works derra July 14, 1986 Corrected Copy Mr. Gary Zech Chief - Vendor Program U.S. Nuclear Regulator Commission Washington, D.C. 20555

Subject:

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

Namco part FEA188-30007 Contact Lever 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 Mile Point have foand 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.) i Tne 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 shipped over 40,000 EA180 switches in the 1 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:

1. Proposing to Niagara Mohawk that they replace cracked contact lever arma 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-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.

8607230262 860714 PDR ADOCK 05000410 S PDR AN ACMF CLFvFL AND COwuNv

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e' NAMCO OONTRot S U. S. Nuclear Regulatory Commission July 14, 1986 Pending the outcome of our life testing 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.

i Verv truLy yours,

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bMMr N. E. Swanson President NAMCO CONTROLS NES/kg Attach.

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

Nine Mlle Pt. #2 P.O. Box 63 Lycoming, NY 13093 i

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