k4D4SC*56

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Jarmy 15, 1996

U.. Hadi 3 uy C loma.L ATM: Dommew Cued Ds Watskm. DC 2540t

ATIINTIow : MC Cpaorusm Cmr

Subj" t todbalm ofd F owdisdl uiEsma of Dolha Pamrsm i 0LCFR21

WeuI en hao Mindr d a posbe d6ect b a basic oaposer t * old prasu y cres a d*UMrl ly hbwed and fherr ib demWd rprouable der 10CIZ1.21(a).

Wr~ m wa remody amdfld of Solid mer Pah-edo Sys=. (OSPS) circals s vrwN a Mily ease delg usea~ri mu lnis Vaof a sylow. The dbia sor My mind ar Ik Fedwwear hdladomn Mmory Circk aid de P10 Soe Rae p Sock Maory Cheik. These cirakIs rely a pualti ft las o provide - outp wafbot allg d. rnuive aory. m oriminl tedag waames diM acw vrity tha bob of he p el lop=l we operalom because s sipdl (e.g., P4 hr Idwar A almdoe. di Wds dhe rehidve mumoy wa prws a dh logic pa pr during in A wop loic iA "olsbs diod, amy prvm *e dsired ep from dub logic gSa.

hr A pklW ad oshs a. SI. doss, l gIc sk palaidm fudwamr isosi on & lit b*Wjml abe r a Of.& l aowm g orr wr vdl sgi. Safty Ibtiosl Wdisess a neo ti ad. lr man pimm, a. higt -. geruior wayr levd ilas a arbines trip frough sodu logic whic lads as aector rip. This. .ido provie a 94 (resor rip) sigal so feudwar oios as ldad wis oaly a lit delay (milalieswdt). For Sequoya Usia 1 2 and Wa barw a turbine IA - fm Il.l sam Iesaor 'a lvl is Iw klmiad uprway md depeds oe dUe propr bSedm o a logs sg wis pua ll Ipus, wa dow sewa Is=ladoW. Th lack of uhedwm blim esud lead as r watcwgrryovv ha e lU or sb tu. plmas.

The m s t chienk is uMed 1r se IO Seow Rag Nock Soueles. Ibis is a bauk-p amedo *N aFdit W aO ai& M hMiM i wdd be damble by sbsuving as On ource rang. was as bies a pews leammed.

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SVIMMARY

Wwl.~g wa aedi o Solid SOW Pwdion SySMm yisis Iwest *"a Sally dod dsaing Sdiau~a assitg of Ib. syueam. This condidin ams discovmed by a .ally dhtes a geinerk rviiew of Logic Sysum murin. Tb. lskm4 av maly mes do wr IsolASam N-my Ciauv*t ed due PIO Sams BMW Slack Mimy CkgulL Wauiiioses rm ainma a vpoisl Mmmy busiDs m U vuily pv pOr opmetosof Ibm ckcubs. No ci*uk ..moi.m.ms m rusquwd * prsn tb. m 'iid ise.

SaarOmanaD IOLMATION

Winiagou~s **%s -odfed ofa Solid Sm Pmsmtion Sysma= on* d ws wo aWly WaWed durng SeMaadnoc uasing odse ysw. This ces.idm wu dimolu id #uimg a sric eviewbc olkgic sysama "ad*g

4Aii htudg. bIuml mm"" ow to Im U 6w. t*a hTm" C612^3MS (WsI) 3W.3

'am),,bm . I06Imr N I . w visap faCregseag.SAS Se1ss

thelmEs 5MearSis

WaplIAC9IC@giinCM

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Ak.. ý- almah'-L

Th io *vWmf Fad m losim ion W y amc a * PIG Sown Nor Block MmmMIs IsrA mQ cb eb IAwmW a Is inmmy hsW Nww 6A dome* also pwAY

- Is 60 nw mm

Tot amw sp-q au mw vsm i o I valo l iasa inudo ýIqcietm - visbl. (i Ip isr~utYlsom ~idade.I sclimb lami pa hvig.qedmps wi dmisr1 ?uaibl Sde do Wlin dw two Mamosy ftrcui whi Is m.11 Sre Iwuiom SyemM 0 Ua I-mo -h i OW Uso Mly mWd wA I S smcis mar.

rVewoweboao mwais eiy acheim

b Oom plo do Clops Fgadwft Vulva vsWigA claOs bob do Foedwotf bcoS yaMS dw MofIuLi FdOWsM valves fom he Isoluloom upeL b oerw VOMOcNioU Fowdwvr busies vias -a Or Vsd by the Turbime ip#Foed W P* W ip sigaW .ad ds .EJ Fcjb OGy "pnow th mobai@6j vlva. TypicWl ducpos of debic sodr s peblm NO c v1od -J ihis Weriides. Ts deasios om'a do v yal *tqpiW- for m of bcm wO ms. Tbis dMaIf"m cam on d b of ip rioby mlg Al uam*un4 ia oagkW boad wed to pevid a y ficia. whiuim Oiw SM15. A mview ofdie SM s ucuiad shs = W =l diftlamm be&w 1 ioylemidom atrs foodwwr sokdo It wu she ud w two Immi IOc echms wmre mud to Imn e bdwsmr isolha ad I* seifi bmple(mu M dis cbs dallw for vunl in die qpsol~n Lh plume is GmooUged I* fview their SSP Sysm scheC10 to *mian w"h

-udois of *da olloing sd aply ft dkii applerim So*da .f ams U ogik sccbim .sainsd ua this bef& N* tm ftom "leda ISIS slcbscs

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TYPCAL PED WATER ISOLAT LOWA(l)I

T v logic di~a m rA ows d Obe wa vals m to be cod on dar admd m on a Sl Ia tio0 or a Snms Goemar HIsHI Wa level This close feedwer valve deend is Ichedl in as a

mmamry Iaruioa wboi tl N4 (UX Trip Bawkr Open) sia is presnt.

ThI d"and for Feedwa&r Valves los is a SI W"" IJ-HI War Level "O" r- nin memry Iatch os bused on N4 "AND" 4 Sual-b (Demd fesck). Feadwer valve r also closed by P4 "AND" Low Tavt It is dWe 5t "OMf" (SUSi I 1) tr the Allwia circui deriprioa dealls. The LOw TVI "AND"14 N clos ie lhbdwer valve i•lbs i raor is ipped (14) and th pl is atm Low Tav aid a eauWl reser clean tr *urwabrr deingd.

BUcdw tmoe circu it us p close bedwar valve ad with o .ou t b eaMive mory mclvd@, th logic byd amus be comuced li uwh a way us i pm the deinmd sigp1 widtou IbviWg

14 P4 sigal pse a te logic lkf. A mniel nmmry circukt aaut perfonm a 2/4 1 AmVdon btM *A iWgnl W IE p m b eu bs m y emu Umyibl sis Ps ovldd by a drmMand aMds

OW nld wahu by a sees paL. Ab oualm umiV mamid w ed th e SI or SO H-NKl povide ft o*n as wc s e lute mNmomyr legi= Y . The NeNd pu would bo provided by dw N lpeL The aQp would be dad back tora p o keep the rn-oy le"hed ul a P4 was rmsoved.

The imwleg Flp shws Fs ei66i" afaatt to iOmmns" Ib bogic f bowa in de abov blssb legis aipe ad dmudtcrio Beaam f t es PAMlm involves Osuig dft circukk S

hws Noi lpI eI Amesl is arte dm fWlld by si pu * amer and would be sletoteses " N .

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NOM. The abw. drafil dsw.t SI in SC "14 hdq OMW at

.Input isok mmy druL Sm qplrn wma i i uU. -1 -dro a "MO dma we ipb.

The absow flpre wasdW dw 01 wims dadbeck cdmI12 impo The swiasb ofm fw Ckrui ad% d combe dmwpqd hr dds dauscr The R dd is dadt bo* do I) Wpow4dt 14 -p Tk 14 opt =rnmw e&bsckis0s3 uiipewbA commanuaisa12 WpuL The SUUGomm HI4a bvd wm t d $ da aT4 impoLIfa WrnSWdApdis apumwdo14 40P

Uin U W ~~ S UTh.03 I. 12Ol ummd. bpams~ mwy usd. lcomu e Fssmdwum Wmi.dumW lobe pimeuW 5 h

01 mwpa m dmyw14 4wis uL Th umSl d=Wi ed ic m.Uimpsad busmo ofm a 01lom a I" ndo14 lopm is prmoL Tkh01OwIt dWbkio et 1 dNWrviuCIno Ac

UIf&lo mm..-1 lfso=m W i.dwss p um a ouT3 sd T4 Wpm% I 2/4Jo&isuoam ad AW

at01609%6dsshwwm vvdm 0 lm 1 0 ThOo liam b.soAMtN t SOkWiL Wds S

WO MM dmamdis enn a 60 bw qm N FFegjsw of vivowmin udrtVot Ifthe

Is* mudWusul aq bg a ouow pmb meguusa .W TW4 lpmw 0* if? lpNe A~~~~o hewing *u.MI.w 4wm (S1 wr SO 1141 is bsiq dwinuhd wil 6a. nmve mmy (sul

Thehellb winiby dob 'j od wi~ A so k m ol- Semco Toe hmL Toon swiltc 55 an on thpms ubI r M 6ItrnOPWA&L Toem m*we 4 do*svs of. a 6 SIT su

bM 0 do Ie~es&kik sb 35S3 UT V."o(dw voIsdui t o 441 bipw NoImxrbu wi1m u Grs~~OWN A*m C.wernsinuto ultUVP4wSiSUS pro

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01 ~~.WW).44ýl Thdo W f *A12 *0 aikr6 himmom" KWN at)

pop se oa hre rlim shW d2/4 Io wim hd SET wim*ch is ried. AkhltmI mat isam, the emoy Tem ieamp itfied te QsOl 01p.

Thu mreMi mM s am a i S1 dma4ow)J W a t14 ad 13 ip. Tm mmoay oepts mka % as ae aM d14 ip is aet Mai ldMi e Mlp via d O/ a 01 2 iqp iade t M( ESET). TL U13 lputs i bypmMed is M Bs ag d or a aLtolo acln i dr p rion. As log tb l4 lapo isa saiodul, te 03101 amale aemum dohe Ihdwsr volv closed dmad. If P4 occum drQ ah 14 dmd.t he 12 (14 03) ime ad ad I (P4) imp ma de 2/4 logic k lat the ammoy.

Loic cidoMi d•l pidp dips ia to dis ammmy micir am dr ir agion by d ma-i aSmmli r-ar. The Sah•wfre iver circubt is ta a t b01 oat b tmd by * Smiamanmde mrr. The Imry tamciC providd by ah ckrui is aWid by SET ad RESET

mamdIos ofdtb SMis .mner. The Iendi tiof thr SI a rS0 MI-HIm dmnd amiMu g FhdMwer val veo clom widtma P4 no M ly wiLd. The ollowim• descibesdi te, rcuit opetioe .

Whon dte memry circuit is sed, e 4 dman d is prem wuti teRESEr swic is psesaud. This *any grpvidd lfofe r2/4 logic x tme ommy lami. Aay bimp at T4or T will ME mmtb mamd hlrt tr 2/4 logic fr mmnxy opemio. For rnape if CJ1O is ope, the P4 (RESET) input aIt I is prmmt. TimS0 HI-W i inpl by presig te SET Swich. This inspa"pe to both ds T3 ad T4 iapu. CRl0 isput ofthe i olatdon frdw T inpK. TheT3 ip wotld he blocked by the opLn CRIO. HowevI , the T4 imar will pi throug tCRA ad IfUll te 24 logic for a Bmeh ory Amd io opm•e. The m as w if CR12 is op and dkde CR10 is opeauiouL Bau. of e 14.03.12,M ad 01 uaapm ar. he SI psa ins ratffeted bydt at arnsemmt. The D ips act like a plmel ilap Ihme affa d a circuit opUtimn. Only tb ciruit ',r th 14 iUpe rquis Crat astig. IfCt; (14) iepe were opea. th SET irput would b rie to oa/ 13 input The combtatoo of ta RESET (1 Il) ad thb SET input l 13 will allow dite may c:ui t to pass nis may ft ac . Ifonly a SI sigml wr peear at th• ! iapur ,b circuit would mt opeu uoail P4 becam pmme

.9

1tW houwcg Oassm di &0 for d oeond logI mpaum %ad to dol tm OWuIWr v-cm ,

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TVPICAL pIDWATUR MOLATIMO LOGIC(S)

The move logic is sila io drn logiA dsripedoc The mml dMlWU 6 = ahis logic U0DW0110 is thL h UninAtm o@f dig P4 sad Low TanV. Low Two Nor FeaaSck ho mhe wkh F4 uW-n can hrb On samoy fliardom Tb. L wv Tavg 'AND" P4 will logtm dohedwarw ah This is sLails ro dw Amt to&c bem. If the tm r is vW (p04) ad 6@ hopnisat Low Tavj. ,6c6dW-tw vaulv willU dos Tbh logio* uramqpm al far fswck of do tel Fedwmr vaves ummd (14 al-min) fip.1 "OR" Low Tavg in colnmideac wIth IM to lach d muamy Biactom

Ths biwing ciqci dumipties "1fa 15 dim lode dIkSem ad a McointAl s&WnuoO JiI Abm od. As beOr, becvme the ctwwu mpiblam Ii&vo tn g di. crcuit shows the t a sMesauu Miii wip Ad da at W P amio Wpmt would be pm11. to tdowt inputs and m iAdfd

an dw lawig by s*W amLu

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_. .. _ . . i. . . .~ .*- . .. .... .

NOTE: Tlwhe Iohe cifrt shows M ll where dhe SI mad SG HI4l algMls we *O"Rtd"* e a pram logic circuit sid ier to the meory drarit O th. same Igapt m. SUeM applustms tOR thus trwo apuu as she lput

Sthe memory circiL.

Thi p mrlle na n of4 and12 are similar to the fir oher loic arungnt discussed For

passing StSG HHI signals immdlay, only CR6 mut be capable of conduction. The 14 nlput ties

to tbh 03 outpu whick to boh thd T3 input nd 01 output. This anuraa nt bypa etihe 12 input as lo a CiCM viable. The circu quir aoutput asoon a n SI or SO HI.HI input isst This is ai..pIird by14 o 03 toT3 and 12. If CR6 ui ope, te cint will not output on jut SUSG HI-W

dened because tf 12 input does not meet thb 24 logic iaput for the msmory tmtion. If CRIU is opn, tha cicuit will provide a output toem th14 input alon. The 12 inpuc semes no ftrrtion a long a 14 inpuT ca be pocesscd.

Tbe tding B s uses mwo Meaory function ts to vri the cicuit operaio The RESET is applied o thu iapur ad simulam P4 being prsnt a all times. The Irt I emoIP at ppli a SET to 1412

end simsules SISO HI-HI imput. The second mnmoy t a pplics a SET to13 and simuaes the Low

tavg inputs. This as ar ueme does not test th CR6 and CR3 diodes.

Pr1 SIrce RamI Slck MemOr Circult

T7 other mn wet bthat has the sam type ofappliation is fbund i the Source Rang Block circuit. ThiT a Uaar is psas a t he 0 ipusi Os Logi cad A4MO in the Sorse Range Block ciruit ta thi c , p10tl i lid bob cu 1 ad I2 apu ofte SR Bock elmory cd 6 is applied at T4 ad th awmu l blct A" n iio aiiippled b iap. The 01 output is tied back to tT3 input to

p-vii~ ~r•dlv uMrawy rmcdoe

Sof tdh iwo Iaemry i l fr bis cicuii ppulis a SET a thi PO iput 10 provip an e a imic

Saleockf lBOt Wthis o bsr ier ti ni l9powerflevelis nd, i SialTasddlob ia

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W pMs* heeWgoSgiFVolp dbngisd. T inptuussoedby? ?10ameetthe2/4 *A- as s is e Te W r sst d oeppooals1ipus s oowadt ht in

r k gi*l, hilO•p emra IiN d& cveLT a cI or C bedn opgsM y be Kbn cd by o mpuusoy amcim oest

WISTRIOUMSo RCOMMINDAT1ONS

Wsiad oue b• h drind r thmt ckruit modiflad m iir tdid m a I WO e mab rwreled enidaow Wedhoue does mrmmmd thtoa specl M noy actio tst be 0ccOP4Wse o wify

dte oprsmtoo of dlu tsoaid diodesin dw c

WutinghouM urconUne te each is review their specifc app6liwion and imp&. Siof th Feedwmar Isolaom cicuitL SOOUt appOIato show he S S O M a to circ Otedr a due ip top bem ory dci. OWL erpp ca5othb SI Ss sr ORcdA on a per lofic cimcuit asId e l 10 ihe aw ry circuit o dr me inut line' . For th

sppliaons whers dt St ad SG -HI inputsm u "OR" a di mcoy i rcuit inpu, to spe al

SM•"y tN are requied because both siogl tinpu we pWldl ip• to the Beroory circuit (see di

fA r Typical Logic Board ComectioNs () i thi blletn). The applicaios that use a scpara

Io*i cicm to "MO dr the ad SO -HI sipals p quire only cr special m•noy test. Te sing"le input is the oy pralel input (,see fir Typical ogic Board ConsGnno (2) in thi bulletin).

For SI and S H-H circuit, opening the P4 input while opaing the SET inputs will low oaly

die SI and 5/0 HWI iLput to operae dwh 01 output Opening P4 can be accomplished by pressing the RESET switch when prfodsinIg tis memory unction te.

Special M ry Tts

Th special mnmy t can be peformed as port of the bi-only sviliace ar dY prfoed O dwe SSPS. Eac pls mu review dhe SSPS s etics and Tcnial Mul d a Sdermuie which piiom(s) of the Mommy Test switch are used to test the A213 mmory circwit. When ,lped to perform the dMumy ftin test for do A213 memosy circuit pes th S

hold t down. At e same de pro the SET switch ad veri•y ta mBmry t=Yest lap lights. Release di SET switch ad vfrif bt • memoiry test np off. Releae RESET switch and

coplet de nor emory fmm ctico atM t for thu poitioa

By holdig th RESET switch. d 2/4 to& fcdr moma y circu* is ony m by the two WPM fom the

Sr~T sitch. If *thdr ofthe two imput diod m opme dhs dlr wil • l o l• t he output eem my u•

emp. This tet must be copled fcra of th s tht povide p l ipu to h logc ccuit.

For dh Source Rap Chirt. a the May Scton for t10 inpt (e.. S506-4 Prms USLT swicb ad old dwt. t At Ah-- Ano dm *timn tb$ SET swirob ad vri dw M ory an

aImp Mms .Mlam M d SET swtch nd veiy he MaOmy t est Ip o .RA t h do RESI T

Iswlb ad coQpl anoml nmoy acion a T. moy•• o e tmp will not lih eihtCRl or

CRu amo9pn le o Ad40 Logi owd.

Fotr sddo"el iairmhem qasdom or ofmmasm plas comma b appropria Wesiibgouse CeAunmml Piedut MW (CPM) for h as o spl• d The CPM will fmrd all infmtdoni to

do ppropitsa podct He syra ebo w.

IINA

IC- ~ L-r ii -I-·~- -~~---- T '- '·I~-F -* l-~- c1-rr

I·

AL INFORMATION or OTHER IVET NUMBER: 33542

LICEXERB: MBSTINGHOUSE ELECTRIC COMPANY CITY: PITTSBURGH REGION: 1

COMITY: STATE: PA LICNSE: AGREEMENT: N

DOCKT:

NRC NOTIFIED BY: HQ OPS OFFICER:

"DURtBNCY CLASS: 10 CFR SECTION: CCCC 31.21

JOHN GALEMBUSH BOB STRANSKY

NOT APPLICABLE

UNSPECIFIED PARAGRAPH

- _Y

NOTIFICATION DATE: NOTIFICATION TIME: EVENT DATE: EVENT TIME: LAST UPDATE DATE:

01/15/98 14:07 [B'.] 01/15/98 00: 00 [EST] 01/15/98

NOTIFICATIONS

VERN HODGE NRR

EVENT TEXT

10 CFR PART 21 REPORT REGARDING TESTING OF SOLID STATE PROTECTION SYSTEM LOGIC

WESTINGHOUSE WAS RECENTLY NOTIFIED OF SOLID STATE PROTECTION SYSTEM (SSPS) CIRCUITS THAT WERE NOT FULLY TESTED DURING SEMI-AUTOMATIC TESTING OF THE SYSTEM. THE CIRCUITS NOT FULLY TESTED ARE THE FEEDWATER ISOLATION MEMORY CIRCUIT AND THE P-10 SOURCE RANGE BLOCK MEMORY CIRCUIT. THESE CIRCUITS RELY ON PARALLELING EACH INPUT TO PROVIDE AN OUTPUT WITHOUT UTILIZING THE RETNTIVE MEMORY. THE ORIGINAL TESTING ARRANGEMENT DID NOT VERIFY THAT BOTH OF THE PARALLEL INPUTS ARE OPERATIONAL BECAUSE THE SIGNAL (E.G., P-4 FOR FEOEWATER ISOLATION) THAT INITIATES THE RETENTIVE MEMORY WAS PRESENT AT THE LOGIC GATE INPUT DURING TESTING. AN OPEN LOGIC INPUT ISOLATION DIODE MAY PREVENT THE DESIRED OUTPUT FROM THE LOGIC GATE,

FOR ALL PLANTS THAT UTILIZE THE SSPS, THIS LOGIC GATE INITIATES FEEDWATER ISOLATION ON A SAFETY INJECTION SIGNAL OR A HI-HI STEAM GENERATOR WATER LEVEL SIGNAL. SAFETY INJECTION INITIATES A REACTOR TRIP AND, FOR MOST PLANTS, THE HI-HI STEAM GENERATOR WATER LEVEL INITIATES A TURBINE TRIP TROUGH SEPARATE LOGIC WHICH LEADS TO A REACTOR TRIP. THESE FUNCTIONS PROVIDE A P-4 (REACTOR TRIP) SIGNAL SO FEEDWATER ISOLATION IS INITIATED WITS ONLY A SLIGHT DELAY (MILLISECONDS). FOR SEQUOYAH UNITS 1 AND 2 AND NTTE BAR THE TURBINE TRIP SIGNAL FROM HI-HI STEAM GENERATOR WATER LEVEL IS NOT IITIATED SEPARATELY AND DEPENDS ON THE PROPRR FUNCTIONING OF THE LOGIC ATE WITH PARALLEL INPUTS, AS DOBS FEEDWATBR ISOLATION. THE LACK OF

FEMXTER ISOLATION COULD LEAD TO WATER CARRYOVER INTO THE STEAM LINES FOR Tl5U PLANTS.

t SAM( TYPE OF CIRCUIT IS USED FOR THE P-10 SOURCE RANGE BLOCK FUNCTION.

(Continued on next page) ^fl u.

4j^'^1TT-: *.*.**C-ni·-C·ICTri*T---T-.--------------- -

ICErSE: WESTINGHOUSB ELECTRI PAGE # 2 OF EVENT NUMBER: 33542

TuIl IS A rACK-UP FUNCTION TO P-6 AND IF BOTH OF THESE MALFUNCTIONED IT LD BE DETECTABLE BY OBSERVING THAT THE SOURCE RANGE WAS NOT BLOCE'D AS

POWER INCREASED..

WESTINGHOUSB HAS DETERMINED THAT CIRCUIT MODIFICATIONS ARE NOT REQUIRED TO TEST BOTH PARALLEL INFUTS. BY PRESSING THE RESET SWITCH, THE RETENTIVE NMORY SIGNAL (E.G., P- 4 FOR FEEDWATER ISOLATION) IS DEFEATED AND THE ABILITY TO OBTAIN AN OUTPUT FROM THE LOGIC GATE CONFIRMS THAT BOTH INPUTS ARB FUNCTIONING. WESTINGHOUSE HAS COMMUNICATED THIS INFORMATION TO ALL PLANTS UTILIZING THE SSPS VIA TECHNICAL BULLETIN ESBU-TB-97-09, DATED DEDCEBER 17, 1997.