ML19302F298

Forwards Analysis of 800523 Trip & Subsequent Safety Injection at Facility.Some Operating Nuclear Plants Lack Controls Restricting Starting of Electrical Motors While Emergency Diesel Generator Is Undergoing Load Tests

ML19302F298
Person / Time
Site:	North Anna
Issue date:	08/20/1980
From:	Michelson C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
References
TASK-AE, TASK-E008, TASK-E8 AEOD-E008, AEOD-E8, NUDOCS 8009240202
Download: ML19302F298 (3)

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, De~ A AUG t0 980 AE0WE0%

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l MErDRANDPt FOR:

EdwaM L. Jorden. Assistant Director for Technical Prograr:s t

Division of Reactor Operations Inspection

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Carlyle titchelsen. Director Office.for Analysis and Evaluation of Operational Data

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StBJECT:

OPERAT!0RAL ESTRICT1015 DURING $URYEILLMCE TESTING OF D1ERCtNCY DIESEL SDERATORS l

L lased on a review of an event t. hat occurred at North Anna. Unit 1. on May 23,1st

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(LER D-47/01T-0 the north Anna Onit 1). it can be concluded that some operzting nuclear plants de not have specific administrative controls restricting the.

' starting of large electrical actors dile as emergency diesel generator (EDG) is undergoing partedic load test sysrating in parallel with the ac,rual power supply.

AIDD believes that there is a need for infbraing licensees of operating reacters regarding the possibility of certajn unreviewed interaction between the onsite g

electrical distribution sys.m and an emergency diesel generater (ED ) underr iy perledic load test that could affect safssty related systas. We consicer ite L

en IE Circular er Inforsstion Notice should be issued requiring licer.stu t; e

twyfer their pleet easite electrical distrihrtion system to assure tSc. the inir p

of the systen has wasidered the effect of electrical transients caused by th-p starting of large electrical autors dile an emergency diesel generater is eperating Sq the test mode. If such considerattens have not been addresed tr.

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me plant design.then the plant operating procedures should be reviset t: ce : i.:-

I spainst starting and tripping of large electrical noten or other ele: -f:c 'cr that would adversely affect the operation of an EDG undergoing perted' 1

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testing.

A brief description of ths event at North Anna Unit 1 and our cc:: cent:

tb emt are provided in the enclosed report.

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l crigi,s.1 Signac ty Osrlyle rich *

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Enclosure:

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• ch el s en, Di et : t: - '..

fa Ste ed Office ich 'calysis and Evalu '

of Operational Data cc w/enclosurt:

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'. CM haview of the Event'st North Anna-1 en May Z3.1930 J'

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";%MWs safety tajestiga hSI).1980. vbile Unit 1 and Unit I were at hot s

.escurred es unit 1 due to high stean< line flow sigt.n f;DhM maleset 4fth leW,T everegs le De Reacter Coolant System (RCS) loops.

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tilewleg a reactor trip that occurred at 2M7 d*l

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,IS M es e sensequence failure of a steam generator feed-t t tess.

ing pre-initial. criticality testing f

lL 45 V.beth sei was bein Os nagentagiAed $enstbruers (RSTs)g e

bst stattse.tr thit l'has two Reactor

@.,;iQ nit I has all three RCPS operating.

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. #lesem generater se htt 1 was undergoing surveillance test

'. aparettag te pere 11el et t 'I P bus.

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Ibe event pas feltleted when the operator started 'A' RCp en Unit 1 at 0135 he eenseguest soltage foduction en "A" BT.,which was tied in'.o "IJ" bus, cau

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1. 38 to plot og land. 'The pesv1taat flew of current caused the normal feed 4Au

[p d y% rester to See *17 but to se directlemal overleed relay actuation.

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E paperienced a Serge 14ed te

' The Itcenses has postulated that this los ijf

',fejection.eessed a voltage serge utteh was transmitted through the battery L,

earner end hattsfles te f !!! taverter skich bles two fuses causing a lost of g?.'y:

ggtef gas.-3.lfle tess~ef Mtel'9as I.!!! removed power from the feedwater fic CJ steen. flew enesareter 9er.e11 three steam genersters producing a high steen li 6^*

fles signe1D Mtal ')es 1-!!! else provides power to the valves in the conp:ne ese11ag water llees te the MPs. An the less of cooling water flow, the op:re tripped all three RCP's' as seguired et 0141 hours0.00163 days <br />0.0392 hours <br />2.331349e-4 weeks <br />5.36505e-5 months <br />. This cauhd the tempernu:

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Se the At3 leaps to drop to.the 1ew law T everage setpoint, which together wti high stees ites. flew at 1 produced the 51 signal. The safety injection syst perfismed as designeds

, during St. the. fellering abnomalities occurn f l

1. upee' receiving en SI signal, the *1N' emergency diesel generater L

estematically started as designed; however, it tripped shortly thereafter en eversf. The licensee has determined that this was due to the genereer.s fa11ere to operate properly.

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.t. A *ht-hi sentalement pressure" alare was locked in due to a fdle:

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temperator eerd due to blown' fuses, apparently when at terr.:15

e c-was restered, to Mtdles.!-!!! at 0148 hoves.

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.o, 81'stpsai uns reset et 4149 hers and $1 was terminated 'at 0151 heum u.er r letdown was este611 stood and eeld leg injectf an was stepped.,

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,c @> 'De principal corrective action taken by the licensee, that' of reyisi c

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)Fr.gr ather large loads if an amergency diesel generator is operating ingperatin

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,i Ifperallel with the onsite electrical distribution systes.'is applicabh te iN,a.tet), operating reactor plants.

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'Lhe generic oncers aristag free such a etrev~tance is that the ED6 uf t :

sver' oeded la responding to the electrical transient causei by the stertiq t has met been.designes.to seasiderinch e,cheme of' the Class 1E emergen the acter.1f the B'erload protection a 1

parational requirements, then the Ex b",s.l._ Anna Iler 89mse.the EM evtput breaker to trip a everleed sty either eense the mersal feeder breaker to the bus to. trip ot

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,f directional'overleed relay actuation, whos provided (as was the case at N u u-ht Q[L;eagertence en overload and subsegment load rejection transient w

-T f;jesuptestse Se safety-related equipment eennected to them (e.g., loss cf vito 1

A' I-III.10pptog the IIerth Anas Onit 1 event). 'If a loss of offsite oc<er even:

4 aos.postsloted and if(the second EM fails to operato (during the Norih k:na RA'd, 41 event, tat setend EM started automatically on a $1 signal. but int *edhtd

?;. ipped ae eserspepds however. effsite power was available), then that woad len M&s itr N.4 (caly eae division of $1888 lt emergency. power source, with some o yfi

$effety related equipment la a degraded. condition, possibly unable to perbra 4.. % 18000ssary esteestic safe shutdown functions.-

g!p;&, P V1 + Sesh possible ietsractions between the soarpency diesel generator and the emite 7

4istribstica systes sesid be sinistaed by the imposition of operational res -ict'

. A z. Mas was done at Ilorth Anna tait 1.

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