ML20136B064

Responds to 790604 Suggestion That Greater Release Might Have Occurred at TMI-2 If Purging Had Been in Progress During Incident.Discusses Containment Isolation.Purging & Venting Are Being Reviewed on Generic Basis

ML20136B064
Person / Time
Site:	Crane
Issue date:	07/16/1979
From:	Harold Denton Office of Nuclear Reactor Regulation
To:	Gilinsky V NRC COMMISSION (OCM)
Shared Package
ML20136B069	List: ML20136B064 ML20136B072
References
NUDOCS 7908150470
Download: ML20136B064 (3)

Text

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JUL 161979 i

F E.'-CPEDUf' FOR : Ccemissioner Cilinsky FRPf':

P. R. Penton, Director Office of *'uclear Peactor Reculation TI'PU:

Fxecutive Director for Operations (signed) T. A.Rehm SUFJECT:

TPI CPf!TAINf'EMT PUPGlf'C Ycur June 4 rcrorandun suggests that a substantially greater arount of radio-activity right have been released at TMI if purcing had been in procress at the tire e# the accident, t'e have conservatively estirated the release for this bypothetical case. The purne systen would have been isolated in this case by darpers actuated by radiation ronitors in the purce discharce lines.

The conitorinc syster perfoming this function is separate frcr the containnert isclation syster and is primarily designed to control discFarpes te levels consistent with 10 CFR part :'O lirits.

Parpers lccated both in the intake and exhaust of each of the two purce trains close upon receipt of a sicral fran the scintillation detectors which ronitor radicactivity in the rurge line dis-l charge. resed upon tFe real time scenario of the TUI-2 accident, these calcu-latiors show that insicnificant radioactive releases would have cccurred both j

rrior tn darper closure and free. leaFace around tFe darpers durinr' the twenty cinutes assured for ranual response by the operator to close the purge isola-tien valves.

?urirq ti.is toenty rinutes of assured relecse, t!'e leaFar'e past the intaFe Mr. rer 'eculd have been unfiltered, with recrEct to radioactivitu, except for a rarticulate irefilter. TFe leakace past the exhaust da'rer, bo"ever, veuld Fwe b(en #iltered by a particulate rrefilter, PEPA filters, cFarcoa.1 adsorbers, ard a 'inal rarF cf HEPA filters. All nomal purge extausts are treated by this

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Ccersis::ioner Gilinsky Indicator lights on Panel 25 in the control roon at FI-P provide a constant sin-nal showing the position of the purae line isolation valves. This display papel is not observable from positions nomally occupied by the operators. Powever, the containment purge radiation monitors alam both audibly and visually to the crerator and should provide sufficient warning to cause the operator to close the purae isolation valve within the twenty minutes the staff norrally uses for manual response.

Uith respect to automatic isolation of purge valves by biqh radiation signal in other operating reactors, the Division of Operating Peactors is presently revieM-inr' the contairrent purne and venting on a generic basis. The Pulletins and Orders and Lessens Learned task forces are also reviewinq containment isolation provi-sions, cenerally. The 00R review is addressing the need for purging nr venting at pmzer and includes consideratien of accidents during tFese operations.

Tt e need for diverse sinnal actuation of containment isolation for all,perating reactors has been identified by the Lessons Learned Tash Force. An action Feine recer ended for irplcrentation by this group will alleviate potential problems in the area you Fave identified. One of the sFort tem recommendations involves the backfit recuirerent for diverse and more selective containrent isolation pro-visions for PWPs and P'APs.

then implerented, this action vill assure that all operating reactors will 1) provide containment isolation on diverse sinnals in confomance with Fection 6.2.4 of the Standard Peview Plan, 2) review isolation provisions for nonessential systers and revise these provisions as necessary, and

2) rodify contairrent isolation designs as necessary to eliminate rotential 'or inadvertant reopening upon reset of the isolation sinnal.

..Qs Farold C. renten, Director Office cf Fuclear Peactor Peculatico cc: CFair'.an Pendrie rov"issioner Kernedy Distribution:

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i 3-Commissioner Gilinsky DISTRIBUTION:

T. Rehm E. Cornell H. Denton E. Case R. Boyd i

R. Mattson V. Stello PSS

0. Muller W. Kreger R. Vollmer D. Eisenhut i

G. Knighton W. Butler J. Collins G. Lainas i

B. Grimes L. Nichols i

R. Bangart NRC PDR Central File NRR Reading File (P-428)

ETSB Reading File ETEB Subject File 20.9 G.Ertter(ED0-06462)

M. Groff C. Paul A. Ferguson i

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H. P. Penton, Director Cffice of t'uclear Peactor Reculatiog

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TFI C0rTAITENT PUFGING

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activity nicht have boon releasc<th purging had been in pregress at t In r=rc~a i t At of the accident,ils have ti " conservativ4 cal =? ; tin te est ra <

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ould have release for this byrotbetical case. 'A Miaec/TFe purge sys er> t in t! e porce been isolated in tSis rase by darpers actuated by radiction ronitors The tronitoring syster, perfonsinq this <unctien is separate i

'ren the containrent isciation systm and-is primarily designed to c dischar"e lines.

rar ners located both Part 2n lirits.

i s close uren receipt o#

ctarccs to levels consi<, tent uith 10 CFD in the intake and exhat.tt of each of the two purge tra t in tbc a sienal frm the scintillation detectors which roritor r.nHeactivity S I-r accident, Ll rased upon the real tire scerario of the

+ese calculations show that insicnificant radioactive re

r rers i ucinn rurce line discFarge, l

recurred Soth prior to dcrrer closure artresrense by tro crerater *c cicse t'o for parual

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?urinc this toonty rinutes of assur.ed release, tSe leakc9e past t'el

1. cr a r arrnr tculd have been urfiltered, vitTFe ledage past the extaust r'arrer, Forever, t i

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Irdicate'r,14Fts on Panel 20 in the control recr at TF'I-? rrovide a constant sic-nal showinh the pcsition of the purne lire isolation valves. This d4rlav rarel is net obser;vable fro" Positions ncrrally occupied by the operators. !'crever, tre contain-ent purge radittien monitors alann both audibly and visually to tFe orerator and shhuld provide sufficient warnine to cause the orcrator to close tFe rurge isolation valve within the twenty minutes the staff nomally uses for manual response. \\

t ith respect to autenatic isolation of rurce valves by birt radiation sinnal in otter oceratinq reactors, the staf# is Presently reviewinc the certainrent nur<]e and ventinc on a pencrik basis. The Fulletins and Orders and Lessons Lcarred task fcrces are also reviewing tFe containc ent purge and ventirn. This review is ad-dressinc the need for purc4ro or ventirq at power and includes corrideration of accidentsdurinatresecreragiens.

The Containrent Systers "ranck. Pes primary restaansibility fer containrent isola-tien licensino review. The T"I-0 conteinrent rurce syster has ':ren evaluated ccccrdinc to the recuirerent set 'forth in FrancF 7echnical Position (PTP) F t.,

"Contairrent Purcing Purinc "crral Tiant Prerations", which recuires in Part t! at ti.e irstrurentation and control syster.s previr'ed to isolate the purne syster lines should he actuated by diverse parareters. The cortainrent porco renitorirn sycte s are renuired by Standard Ocvieu Plan P.rP) Eection 11.E, ""rncess and r"luent Padiological onitorinc and Sarrlinq Svsters", and are reviewed hv the cfunnt Treatrent Systees Franch.

S'arold P.' Perten, Piractrr Office nf Yucicar enacter erulation ec: &airran Pondrie e& rissionar "ennedv Co-n'issioner " rad #nrd err-issioner Mearne

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7"I C"': TAI'M?'T PUPGIFC Vcor Jure 1 renorandur su" costs that a substantially qreater arcunt c' rc'fic.-

i activit[e o#y richt have been releated at 3'! if reroirg bad been in procrets at tFe tir t5c accident. Ye kave conservatively estirated the releate for

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tFit Nyrett sical case. The rurce syster would have been isolated it thi!

case 'v errers actuated Sy raciatien reniters in tSo perce discharce lines.

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Tic rcnitcrirq svstor Perferrine this function is serarato frc~ the centattrort isciation syttrr' and is prirarily desicned to enntrol ditc' arces tc invels r

consistent 5,ith tr CT*' nart 70 lirits.

Parrers !ccatov bcth in t'e intMe and c?aur.t of each ce the tre purce trairt close uron receirt of a ':icral 'rar t'e scir.tillatten detectors vtic$ rcritor radicactivity in tFe rurae lina ' f :-

c' arce. ate' teren the real tire scerario c# the T' !-? accident, these calcu-latfors sboit that insicni'icant radicactive releaces muld have cccurred t.cth

,"h cutts assurcdrict to dar rer closure and 'rcr lealace arcund tFe tarpers durire the twenty i

for rarual rectr'nse by the crerater to close the curae i'cla-tien valves.

e r i r o tHs b enty "inutes of a,sured relecse, tre Inatace rest t' 9 frtake c rer sculd tave been unfiltered, with retrect te rer.iractivi'v, orcurt #ce a rart icul.3te trafilter. ibe leatar;e part ;Fe c,eanst dar rer, Wever, veule tavo Penn 'iltered ':y a r:rticulate rrr#ilter, FfM filtars, c! arccal af'torbers, and j

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-T-Irdicator lir hts on nanel r' in the control roor at TI-P rrevide a constant sin-ral sForine t'e position of the rurce line isolatien valves.

This dis;1ay p.1rel is r,ct c5servallo fry: positions rer ally nccupirni by the operators. Fettever, the certainrent per e radiation ronitors alare both cudibly and visually to the crrrator and should Provide'sufficier.t warnity to cause the operator tc close tFe i:crae isolation valve uitbin the twenty rinutes the st3'f norrally uses fer canual resrorse.

':ith respect to autoratic isolation n' purce valves by hich radiation sinnal in other creratinn reactors, the rivision of f'reratinq onactors ie. creeoatly revier-irc tPa containe ent pur"e arr' ventina en a qeneric basis. The "u11etins and r ders r

end lessens Learner' task forces are also reviewinc contaireant isclaticn trovi-l sions, -ontrally. Tbo cro revieu 1e, addressico tFe need fer nurcino er ventire at rever and includes consideratien cf accidents durinn those conrations.-

iPe aNd for diverse stenal ectnetion c# containrent isobtion 'cr all creratirc rnactors ! as S ecn identified by tFe LMecns Learard Tett rcree.

f.n action Feir" rvr ' ended for irpiecntation by this creen will allevia+c retential rrchiers in t' e arca.%u bave icentified. One of. the sFort terr recorrendations involves the ! ecLfit recuirerent 'cr <11 verse and ~ ore telective containrent isclaticn irc-visions for P.rs and Ors. tren irplerented, this action will assure that all ornratinc reacters uill 1) r.revide contain ent isolation er divers,r si~nals in cen'orearce with "ection 0.2.a cf the Starr'arr* revice Plan, 7) revicu iscicticn

revisiens fer nonessertial systers aad revise these provisiers as nneessary, and

) "cdify contair: rent isolation desinns as necessary to elirirate poter.tial 'or inMyertant recpening u;on reset cf the ise.latica sienal.

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T. Rehn E. Cornell P. Denton E. Case R. Ecyd P. t'attson

v. Stello DSS C. "uller Krecer P. t!allrer D. Eisenhut C. Kniobton

'.J. Putler J. Collins G. Lainas C. Crires L. "ichols P. Pangart t'pc prp Central file f.rP Peadinc file (P-42P)

ETER Peading File ETSP Sutrject File 20.9

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FROM:

ACTION CONTROL DATES CONTROL NO y gg(geggy Gjjj g y COMPL DEADLINE t;/111[73 06462 ACKNOWLEDGMENT DATE OF DOCUMENT INTERIM REPLY b[d((.8 TO:

PREPARE FOR SIGNATURE OF:

liarold Denten FINAL REPLY /

O CHAIRMAN FILE LOCATION

/

O EXECUTIVE DIRECTOR OTHER:

M ten DESCRIPTION O LETTE R. C MEMO C REPORT C OTHER SPECI AL INSTRUCTIONS OR REMARKS Qwstions on unat would nave nappened if tin contairasent ventilation valves had been opm for containasnt p; tug at the time of the mi accident CLASSIFIED DATA OOCUMENT/ COPY NO.

CLASSIFICATION l NUMBER OF PAGES CATEGORY POSTAL REGISTRY NO.

C NSI C RD C FRD ASSIGNED TO:

DATE INFORMATION ROUTING LEG AL REVIEW G FINAL C COPY 9,

gj f79 gggjg ASSIGNED TO:

DATE G AL OBJECTIONS DE C EDO ADMIN & CO ARES BR

(,Uffdl] }

EXT.

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COMMENTS NOTIFY:

l EXT.

f JCAE NOTIFICATION RECOMMENDED:

O YES O NO NRC FORM 232 EXECdTIVE DIRECTOR FOR OPERATIONS '

00 NOT REMOVE THIS COPY PRINCIPAL CORRESPONDENCE CONTROL l