ML20005A593

Interim Deficiency Rept Re Vol Control Tank Level Instrumentation Control Sys,Initially Reported 810521.Plant Procedures Will Be Reviewed to Assure That Operator Will Be Alerted to Take Appropriate Action

ML20005A593
Person / Time
Site:	Seabrook
Issue date:	06/18/1981
From:	Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, SBN-164, SNB-164, NUDOCS 8106300482
Download: ML20005A593 (2)

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Attention: Office of Inspect ion and Enfo rc c,=nt 7.. f e r..n c e s : 1. "ocket ?;o . 50 t 4 3 a n d 50 ',' 4

?. Telecon of ?!ay 21, 1991 het-.en R. r; .21 10 , 'WC .nd .

D. Maidt nd , iAEC 10 CFR 50.55(e) Defici.ncy E. port on Control and P r o t e c t f .:, n S * ;m : tm Inte: ., c t ; o n Vol u.me Con t r ol ~a nk ' e vel Otar Sir:

On May 21, 1981 we reported that 'J. s t i nghou se had identi fied a control and prc.t ec t ion sys t em in te ra c t ion conce rn ir.volvi ng the Volume Control Tank (VCT) le vel ins t rumentation con t rol system. This report is bei ng fil-d in ai cordance with the thi r ty day repor ting requi rement s of 10 CFR 50.55 (e).

The f ollowi ng di scussion describes the system interaction concern. Mseme the plant is opera ting with a cent rif ugal cha rging pump performing the norral cha rgi ng f unct ion. (!;ormally one of the three a vai l a bl e cha rging pumps is ri.e.ing .!th another as standby.) A failure of the VCT level control syst-m c .e e s the letdown flow to be diverted to the li qud hol dup tank. The LCT liquid i nventory dec reaws due to normal cha rging sit hout any .<.. up to the VCT ef a Ie:dcwn. 'Ji t hou t ope ra t o r i nte rvention the VCT could pty <ausing the ep-ra ting cent rif ugal charging ptenp to he :3a. aged due to irss of soction fluid. If it is f urthe r assumed that one c% r;;ing pt:p is out of se rv ice , as alirwed by the Technical Specifications, there wcuid then be only one

r. ,ai ring .ndacated pu p available to prceide M eup to the r. actor coolant s;,4 t ea as r eq ui r ed by l e t d cwn and r oa. : v r .. <.o : an t ps -p t al ' ak ge .

The one r...u;ning ump daes not thcn eet the Cngle 'a!Iure c r i t ,- r i o n .

yolicwing the failure in the VCT level esnt rol systen, the opera t ur -oul d ha ve a;pr nirately ten minutes to transfer the chac3 ing pump suction froc the VCT i

c :' e 6T or to s Mply stop the 7:.np or to r .. s t o r e ie 2 wn to :he u.T ro

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U .S . %c: : r E< gelato ry Cormi ss *cn Fase 2 S E N--164 I f r.o e p. r a t o r .4 c t i o n . e c u r s a t this t i me , t'r.n the p u.rp in opera t ion c oul d be d- 43. d .' ae to loss of 'uction, snd t he pi ent wculd continue to lese i r. vent ory due to etdcwn. "o cver, this is a siev 'ess in wa t e r i nven t o ry. '.u t or.a t i c 1.- : ' r. vn iso'ation sh oul d c.c c u r . "v .:n e i t h ,u t : 9idesn i so a t ion or perator 2 : -- 3: 'm,  ;;pr .3: 21 y t eo .r ruid e .e ;. io r t o cc re .'c - r; . -~, e

-:vr mW, d L.,v e c o ' : ; .'. rai e t :e to 41?gn the 3- ndby ; - :p t o t*e .J ST .

It ' s 'l . s t. i j :se 's pos it ion 'd -e .v u r .4 t ti--21y ep- ator act n c.in

-ga t e t h i s sce:u r io ar.d pos i t ively dd re :s the idcntif'-d concern. Scibrcok is . c i! pr ed wi t h ins t ri.ta n t re:4 hut s ehich -nuld i ndi c at e the pro. ace of this sitestion, in addition, we have numercus alar:s which -ould be ectt ted at various tices in the event.

Plant procedures will be revie-ed to assure that the operator sould be prope rly aler t ed to this s it ua t 'on and would take the appropriate action r.ccescary to assure an adequa t e wa f e r supply to the charging penps in the e ent of a tCT evel cc nt rol svstra failure.

S' uld f urt l.er ct ion be r equi r. d as a .esult of ddit icnal NRC cc nce rns , -e sill cr ypraise e,ur positica and inforc you a . c o r s'i ng l y .

Very truly years,

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L 4,;g ((N's's

[/ / b John DeViacentis Project Manager D O!: see t

F P00R ORIGINAL

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