PNO-I-93-061, on 931104 & 1106,EDG Number 1 & 2,failed auto-load Test When Loads Did Not Sequence on Emergency Bus During Simulated Loss of Offsite Power W/Safety Injection Signal.Ait Sent to Review Circumstances

PNO-I-93-061:on 931104 & 1106,EDG Number 1 & 2,failed auto-load Test When Loads Did Not Sequence on Emergency Bus During Simulated Loss of Offsite Power W/Safety Injection Signal.Ait Sent to Review Circumstances

ML20059J767
Person / Time
Site:	Beaver Valley
Issue date:	11/09/1993
From:	Lazarus W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
References
PNO-I-93-061, PNO-I-93-61, NUDOCS 9311150041
Download: ML20059J767 (2)

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. DCS No: 50412931106 g Date: November 9,1993 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PN1-9361 This preliminary notincation constitutes S.AR1,Y notice of events of POSSIBLE safety or public interest significance. The information is as initia0y received without verification or evaluation, and is basically all that is known by the Region I staff on thk dc.

Facility: Licensee Emergency Classincation:

Duquesne Light Co. Notification of Unusual Event Beaver Valley 2 Alert Shippingpon, Pennsylvania Site Area Emergency -

Genem! Emergency  !

X Not Applicable Docket No. 50-412 1 License No.. NPF-73 Event No.: 26326 Event Location Code: POW

Subject:

EDG LOAD SEQUENCER FAILURES While the plant was in the Cold Shutdown Mode, both the No. I and No. 2 emergency diesel generators (EDGs) failed the auto-load test on November 4 and November 6,1993, respectively. The test failed when loads did not sequence on to the emergency bus during a simulated loss of offsite power with a safety injection signal.

The Duquesne Light Company (DLC) was evaluating Automatic Timing & Contmis Company, Inc.

(ATC) Model 365A Long Range Timer relays that they pmliminarily concluded may have caused the sequencer failure. The relay malfunction was intermittent; and, the relays wem commercial grade items that were dedicated by Wyle l2boratories.

DLC uses the ATC Model 365A relays in several safety related applications at Unit 2; however, the specific configuration of the EDG circuitry which affected the operation of the miay was unique. The affected relays were installed during the last refueling outage. DLC has evaluated the impact of the failure on the plant in the Cold Shutdown Mode and has concluded no impact on plant safety. Unit 1 does not use the ATC Model 365A mlays.

Region I has sent an Augmented Inspection Team (AIT) to review the circumstances and evaluate the safety significance of the recent failures of the EDG load sequencers. The AIT was initiated because of the common-mode failure identified in the emergency diesel generator system, the possible generic implications which may exist for the design and operation of the relays used in the sequencer circuit, and the complexity related to the root cause(s) of these failures.

The Commonwealth of Pennsylvania has been notified. Region I is issuing a press release. The NRC was notified of this event at 3:27 p.m. on November 6,1993, by licensee emergency notification. This preliminary notification was current as of 11:00 a.m. on November 9.

Contact:

William L Lazams 215-337-5232 9311150041 931109  !

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f DCS No: 50412931104

- Date: November 9,1993 i i

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PN1-9361 DISTRIBUTION: .

OWFN MNBB L-St. NL Mail: ADM:DMB -

Chainnan Selin AEOD PDR RES DOT; Tans only** - .,

Comm. Rogers IRM Comm. Remick OIG NRC Ops Ctr Comm. de Planque .o ..'

OCAA INPO** Z 7'" '

OlP NSAC** [f _$ev#< m Phillips OCA EDO. ACRS i OGC NMSS ,

OPA NRR** (Phone Verif: A. Byrdsong 964-1168 or 964-1166) ,

SP Regional Offices RI Resident Offi 'M sww  ;

OIG L.icensee: / 2: 3/m (Reactor Licensees) r

• • Orncral Un1 ftw wmtmg PNs t*y FAX Region I Form 83 'f (Rev. August 1993)

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