ML20040B202

Final Deficiency Rept Re Short Circuit Bracing in GE Metal Clad Switchgear Determined by GE Not to Have Intended Momentary Short Circuit Withstand Capability,Initially Reported on 811203.No Reportable Deficiency Exists

ML20040B202
Person / Time
Site:	Shoreham File:Long Island Lighting Company icon.png
Issue date:	01/07/1982
From:	Milligan M LONG ISLAND LIGHTING CO.
To:	Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, SNRC-653, NUDOCS 8201250264
Download: ML20040B202 (2)

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l LONG ISLAND LIGHTING COM PANY

.v 14t'O a%veuru SHOREH AM NUCLE AR POWER STATION P O HOK 61N, NORTH COtJNTRY ROAD e WADING HIVE H. N.Y.11792 January 7, 1981 S tJI1C- 6 5 3 Mr. Ronald C. Ilaynes Regional Administrator, Region 1 U.S. !Juclear Regulatory Conmtssion 631 Pa rk Avenue 'gr.g (

17 King of Pruncia, PA 19404 -

LO!JG ISLAIJD LIGIITIIJG COMPAIJY Shoreham IJuclear Power Station - Unit 1' '

Docket IJo. 50-322 '

Dear Mr. I!aynes:

l On December 3, 1981, in accordance with 10 CFR50. 5 5 (e) , we leported verbally to Region 1 a potential deficiency concerning the short circuit bracing in our General Electric 4160 Volt metal-clad switchgear which were determined by General Electric nt to have their intended momentary short circuit withstand capability of 80,000 amperes. This letter serves as our ?O-day written report of this potential deficiency.

Doncription of Deticiency Re' { ua 1. f icit t ion LesLL by G.E. have i.ndicated that the electrical bun suliports and bracing in some of their vertical lift metal-clad taitch.Jear do not have their intended momentary short ci rcu i.t withstand capability of 80,000 amperen. These tests showed that

'he mai.a an! runback bus supports in nome of these switchgear ta u unable to withstand the full short circuit duty of their rettin, without oxperiencing some damage to the bun supports and potenti.il additional problema due to the weakening of such supports.

(; . U . Informed us that this deficiency was discovered during factory ,

testing and that they have no record of an,r field failures caused  !

by short circuit currents. They also informed us that no I modificati.on would be necessary unless the t.otential short circuit d u t.y to our switchgear was in excens of 66,000 amperes.

A t. the time of our verbal report to Region 1, we had determined that Shoreham's seven 4,160 volt metal-clad switchgear were subject to the dorating of short circuit capability described in G.E. Service Advice Letter. Our preliminary f ault duty calculations l l

I O201250264 820107 PDR ADOCK 05000322 S PDR 460

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SNRd-653

_ January. 7, 1982 l

Page Two 1,

i i i also showed that the required short circuit capability for Shoreham's three Cat IE 4,160 volt switchgear (the remaining four 4,160 volt switchgear are all Cat II) might be in excess of the newly imposed 66,000 ampere rating.

These calculations have been finalized by our Architect Engineer and it has been determined that the maximum short circuit duty available to Shoreham's three Class IE switchgear is less than their 66KA rating. It has, however, been determined that two of Shoreham's four Cat II switchgear have potential maximum short circuit duties in excess of their new 66KA rating and will, th ere fore , require that additional and stronger bus supports be installed.

Corrective Action Since the short circuit withstand capability of Shoreham's Cat IE netal-clad.switchgear has been determined to be greater than the calculated maximum potential fault currents, we have concluded that a reportable deficiency under 10CFR50.55(e) does not exist

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in this instance. Ele are, however, pursuing G.E. to obtain the parts and engineering necessary to install the supports needed to restode the short circuit ' rating for two of our Cat II switchgear to their intended rating of 80KA. We are also pursuing G.E. to obtain the parts and engineering necessary for a future restoration of the remaining Cat II and Cat IE switchgear to their intended rating of 80KA to provide adequate short circuit withstand capability margin for future load additions.

Very truly yours,

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M. II . Milligan Project Engineer Shorbham Nuclear Power Station TJS/pd cc. Mr. Victor Stello, Director NRC Office of Inspection and Enforcement Division of Reactor Operations Inspection Washington, D.C. 20555 Mr. J. liiggins Site - NRC Trailer

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