ML20097J635

Part 21 Rept Re Intermittent Failure of DG Relay Mfg by Amerace Electronic Components.Suspect Relays at Plants Identified & Replaced.Amerace Indicated That Operators & QC Personnel Made Aware of Need for Proper Soldering

ML20097J635
Person / Time
Site:	Byron, Braidwood
Issue date:	01/30/1996
From:	Kofron K COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-96 BYRON-96-0023, BYRON-96-23, NUDOCS 9602050070
Download: ML20097J635 (4)

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g. Commonwealth Edimu Onnpany

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II)run Generaung Station ~

. 4150 North German Church Road liyron. IL 610ln9M 6

'; Tcl Hi&2M544i January 30,1996 LTR: BYRON 96-0023 FILE: 2.01.0703

' U. S. Nuclear Regulatory Commission Washington, DC 20555 -

Attention: Document Control Desk ,

Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2 L

10 CFR Part 21 Notification Intermittent Failure of Diesel Generator Relay NRC Dockets 50-454 and 50-455 NRC Dockets 50-456.and 50-457 )

i Applicability This notification is submitted in accordance with the requirements of 10 CFR Part 21, l Section 21.21(b),21.3a(3), and 21.3d(4). i l

I Identification of Facilities and Components Byron Nuclear Generating Station Units 1 and 2 Braidwood Nuclear Generating Station Units 1 and 2 130 Diesel Generator Electrica: Relays procured from Amerace Corporation  !

Part #: EGPDRC2017003, date coded #9245 i

..ldtntification of Component Manufacturer /SupplicI

- Amerace Electronic Components 7474 Utilities Road Punta Gorda, Florida 33982 9602050070 960130 PDR- ADOCK 05003454 S PDR- //

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Byron Ltr:' 96-0023 January 30,1996 Page 2 Naturg..qf_D_gfsg1 f

The' defect is related to a'n incomplete solder process on the coil termination to the transient suppression assembly board on the subject relays. The relays were manufactured by Amerace and provided specific to Comed. The defective relay consists of a nuclear dedicated relay "EGPD" with the commercial"R" option. ' The commercial grade option is an add-on board to the relay which consists of an internal diode which suppresses a coil deenergization transient. The defective solderjoint occurred at the interface between the relay and the add-on board. These relays were provided to Comed for use as replacement parts in the Emergency Diesel Generator (D/G) local control panels at Comed's nuclear stations.

On November 16,1995, an attempt was made to start the 1 A D/G at Byron Station. The l A D/G started; however, the D/G did not come up to full speed. The D/G then shutdown with no trip indications. A second start attempt was performed and the D/G started and operated normally. An investigation determined that a relay in the D/G local control panel was intermittently failing to energize. This intermittent failure was the apparent cause of the D/G to come up to full speed.' The suspect relay was replaced and

- the 1 A D/G ran normally aller the relay replacement. The failed relay and two (2) previously replaced relays from the same date code (#9245) were sent to Comed's System Material Analysis Department (SMAD) for evaluation. SMAD subsequently determined that two (2) of the three (3) analyzed relays were intermittently failing due to a cold solder joint. Comed determined that all relays from the date code, #9245, were potentially suspect. All relays from the suspect date code were confirmed to be installed only at Byron and Braidwood Stations. Subsequent testing performed by Comed on the suspect relays from the 9245 date code has revealed that approximately 50% of the relays were improperly soldered and subject to the intermittent failure mechanism. 1 Time of Discoverv The failure of the l A D/G during its surveillance run occurred on i1/16/95. Comed determined that the failure was a potential defect subject to the provisions of 10CFR21 on 12/5/95. Final determination that the defect was reportable per 10CFR21 was made on 1/26/96, i

Number and Location of All Defgtive Components: ,

Per the vendor, date code #9245 for part # EGPDRC2017003 consisted of 130 relays, all of which were provided to Comed. Of the 130 relays in lot #9245,100 were installed at 1 Byron Station and 21 were installed at Braidwood Station at the time of the interrupted >

surveillance run on the Byron l A D/G on 11/16/95.

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, . ' Byron

Ltr? 96-0023?-

' January 30,1996 -

t Page 3 Concqtive Actions; 21mmediately upon identification that the entire #9245 date code of relays was suspect, iComEd initiated replacement activities at Byron and Braidwood Stations. All suspect -

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' relays at Byron and Braidwood Stations have been identified and replaced with fully.1 p l qualified'relaysJ Note that some relays from date code #9245 were removed from their u respective D/G control panels and subsequently reinstalled after shop testing was

- performed to ensure that the relays were properly soldered.

Per Comed's request, Amerace conducted an extensive investigation on the subject relays.

' Amerace's investigation included a visit by Amerace representatives to Comed's SMAD testing facilities. In a 1/10/96 letter from Amerace to Comed, Amecace indicated that they had identified the root'cause of the defect, defined the scope of the relays affected and taken corrective" action to prevent similaro' ccurrence. Amerace also indicated that no other similar failures had been identified over the past three years for their various relay configurations. The scope of Amerace's review included over 18,000 relays provided to

-both nuclear and non-nuclear customers. Amerace's conclusion is that the failure is L isolated to date code #9245, all of which was provided to Comed. As furtherjustification

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for the conclusion that the defect is isolated to the #9245 date code, Comed has - ,

- performed extensive testing of 37 similar relays from another date code (#9448) and no defective relays were identified.

' In 1995, Amerace moved the assembly of the relay product line from Control Products Corporation in Grafton, Wisconsin to Amerace's in-house facilities in Punta Gorda, Florida. In the 1/10/96 letter to Comed, Amerace indicated that their operators and QC

s . personnel have been counseled on the nature of this defect and have been made aware of

' the need for proper soldering techniques.

10 CFR 21 Evaluation d

The identified defect directly led to the interrupted surveillance run of the 1 A D/G at Byron' Station on 11/16/95. The defective faulty relay did not lead to an incident of E . significant magnitude. However, there was potential for a more significant event in a circumstance where Emergency AC power was needed. Therefore, Comed has

1. determined that the improper solder process on the subject relays does constitute a defect per the requ' irements of 10CFR21land is reportable to the NRC.

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• Byron Ltr: 96--23

. January 30,1996 Page 4

-Contact Questions pertaining to this notification should be addressed to:

BradleyJ. Adams

' Site Engineering Comed Byron Station 4450 N. German Church Road Byron, Illinois 61010 '

(815) 234-5441 x2979 Since ely, K. L. Kofro Station Manager Byron Nuclear Power Station KLK/BA/rp cc: H. Miller, Regional Administrator-Rill H. Peterson, Senior Resident inspector (Byron)

C. Phillips, Senior Resident Inspector (Braidwood)

G. Dick - NRR R. Assa - NRR Office of Nuclear Facility Safety - IDNS (p:\96byhrs'960021docW12996')

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