ML19210C772

Summary of 790430,0501 & 09 Meetings of ACRS Ad Hoc Subcommittee on TMI-2 Accident Implications Re Nuclear Power Plant Design in Washington,Dc Re Nuclear Safety Design, Policy,Criteria Research & Plant Operation

ML19210C772
Person / Time
Issue date:	07/30/1979
From:	Advisory Committee on Reactor Safeguards
To:	Advisory Committee on Reactor Safeguards
References
ACRS-1635, NUDOCS 7911200085
Download: ML19210C772 (60)

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i MINUTES OF THE A0 HOC SUBCOMMITTEE MEETING y g7g 4ILE ISLAND 2 AOCIDENT - IMPLICATIONS RESAROINS

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NUCLEAR POWER PLANT DESIG*,

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ir,. s.or-the set.ence and timing o' the NR Sta" speakers f:- : e Mr. 2. Ross discusse:

co-nin; ree:in; witm tae Su:::rmittee.

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EVENTS OF TrE LAST SEVE', CAYS AT TM* (Transcri:t Pa;es 20-25?

Mr. :. Ross, NRC Sta",/ ti scusse: tne events Of tre last sevea days startin; ai t-tne Co--i s si:r. Teeti n ; c f Mcnday a 'te rr.ocr., A;ril 2 3r:.

uring that me e ti r. ;, "r - E. Case, %:." Sta'#, made a pers cai c:servatice t at Me tncu;9:

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on tne seasitivity Of feedaater transien*s, reliability, tre perf rmance as;ects Of a.xili ary fee aater, and :lart transient analysis diffi:wities.

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The Offi:e of Inspection and En'occement is :enductin; an investi;ati e and aill outlish a ne :nrenology of the TMI Ac:ident. This encon 10;y will n

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.v ur.til tne investi;ation is completed. The final re: Ort is n:w s:Neduled for publica-tice in August. The basis for the ISE Licensee Sulletins79-05A, 79-06A and 3 that aere issued t: licensees is the initial threnclogy that was developed early ir. tne at:ident review.

Mr. Jordan said that the basic facts of the ccident have nct 1372 274

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cha ge:, but the fine cetati is being cnanged anc refined.

The chr0nci gy is

sir; Ore:ared at t*e Region ! cffice and the ACES could get detailed informati r

- t e en re n:1 :;. at a t : f f t :e. In response to a cuestice from Mr. Michelsen.

• i r. Jerdan sai: trat i# any :# tne information gatnere: cnanges t e informatica Or:.1:e: ir t e 5E b.'leti 5. a :nange acult be issae:.

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1. :ne 15E investigati:-.

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an: !3. esalaati ; ins :e #ormar:e Of tne li:enses as a : asis fee cor-e:tive a:tice.

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envi rcr.msr* a ' r ati:* :;i:3 0:nditions from tne time c' t e beginning C until midnignt on March 31st, and (2) factual information concerning the condition of tne plant and the envircreent and the performance of tne licensee subsecuent to the peri:d investigated in part I.

In response to a question from tne Cnairman, Mr-Jor an said that tne investigation will not evaluate the NRC Staff actions but only state the fact of the NRC action.

In response to cuestions from Subcommittee

.i mem:ers, Mr. Jordan said he believes the Office of Inspection and Enforcement will be able to ascertain whetner the energency operating procedures carried out by the licensee were appropriate for the incident at that time. The review of the performar:S of operators will include all personnel directly involved in managing and supervision 13r72 27r3

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In response to a question from Mr. Ray, Mr. Jordan said that the auxiliary feedwateYvalves were locked and tagged in a locked position in tne C0 rte:

room, but that on :ne 22nd a licensing examiner noted nat the valves were not close:.

Several Committee membe s ex:ressed concern that the final enr nclo;y c' :ne accice t

.ill not be publishec artil A; gust an that in tne :eanti*e in':r ati:- t*at is needed for the s*J:. Of tre a: icent w111 ec t :e' a.a i ; aci d,

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Jceda" ::*tinued / cis:Ussi*g **e investigatica w*i:* tas C##1:e

1. In se:11 Y and E-f:r:re-t is : Orca:tir; con e-nia; the litersee's :13-; Of f-site are on-si te emerge-: res:0 se 13-Tais investigation ill als cevelc: a :etailed :nr n: :;,-

of *ne im;ieceata :i:r O' :ne emergency pl ans, witr e :ca s t s or 19e treliness 0 #

no ti fic a -i:n.

Mr. Mi:neisOn ex: esse: a cesies : discuss e Orc e ;-es f:- react:r tri:, less of rea:::r 00cl ant, an: s ation Ola:k:ut that were in e'fe:t :rior :: :ne at:icer.t.

He fel* *nat it is in:Ortart 10 track wnat the Ocera:Or was su0:Ose t0 na7e 00ne i" these situa* ions and to verify that he was a:carently following current ;recedure.

Mr. Jcrdan :encluded his presentation by reviewing the actions

• hat are no* being c0vered in the investigation. They are:

(1) evaluations of the actions Of the NRC Staff or its organizational components; (2) evaluation of tne action Of other agencies during the course of the accident or recovery peried; an: (3) :ne regulatgry process or the need for rules and regulaticns, changes, or safety resear:n, 2 276

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_m sG, o TMI-2 Implications LICENSEE RESPONSES TO ILE BULLETINS 79-05 AND 79 5. Var;a, NRC Sta#f Pages 60-91) that have Wr. Varga reviewed the ILE bulletins sent to licensees and the responses teen re:elved ue :: new. Sulletins 79-05,79-05A, and 79-05B aere sent to Babcock Wil::/, N555 licensees, and Bulletins 79-06, 79-C6:, anc 79-C6A, Rev. 1 went an:

Tants, an: Sulleti-79-:3 we-: ::

C:r:vstie Engineerir; and Westingnouse :

Ociling water react: cia-:s.

me ';:. 5:3" - as :: :l eted i ts re.i ev. :' : e res:enses :: Balleti-79-05A. The res: se na..e ;:. -

a ga sai: -a: ::rsi:eri ; :-e orce-s t a:

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"3 79-:55 ma be ::mtire:

B&W rea:::rs,

e Stafs evalua tier f:- Eulletins79-05A an:

T*e res enses to 5;11etin 79-05A have in gene a' :es sails'a:::

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r-howeve, there a-e s:re attitional cuesti:ns and sore additiera' deta'is that t*e re: aire fr:r tne li:ersess.

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free :ne Chairman regascing training :eing d:re On in-In res; ase :: a :uestier is n:t extensive.

S&W simsiat:r, Mr. Varga said tnat the training being condu::e:

It is a one day training and focuses on the general concerns as indicated in the chronology of tne TMI-2 accident.

The responses to Bulletin 79-C6A have been received and the Staff is beginning their As was The responses to Bulletin 79-065 are Oue Or Ma/

rev i ew of those res;onses.

tne case in the B&W review, there is some clarification required in tne responses /

and in one or two instances licensees have taken scce exceptiens to tne tulletins.

make sure tnat the In res:ense to a cuestion frem Dr. Catton regarding steps ::

c:erating roce is aware of these bulletins. *1r. Varga said that ILE inspectors have been dispatched to the plant with the intent to go over the bulletins witn control 1372 277

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G a TMI-2 Implications room operators and supervisory personnel.

Dr. Cat:0n also asked if operator He had come to the con-training with regard to, thermal hydraulics is adequa*e.

clusi0n :nat 10-12~- of the training is s;ent on things related to the Three Mile Islanc Accident. Mr. Varga responded that the grou reviewing the responses t0 and 5056 the Bulletins is making a list Of rec 0mmendations arising fr:e tne review of tnese rec 0m*encati0c5 are for im0 roved 00 era:Or trainia.g.

Dr. Kerr Ouestione:

a9 a titrary value an: suggestec *na:

the selection cf 10-12' as beirg 50menrat 0 i t i s creca *u-t t0 try to decide w9at percert ought t De devotec :: ther~al ny0rauli s *rai"ir;.

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NRC 571.~~ MEETINGS WIT" aESTINGHOUSE ANO COM5USTION EN3INEERINS A. Inada-i, N ~

(Transcri t Da;es 93-1 Q -- NOTE. Trans:-ip*. Pages 121-135 a-e misciacee, tnese pa;ei shcula Oe placed folloaing Dage 157.

Mr. Thade.' reported ina; tre NRC Staf# has met aith Westingh0use twi:e to discuss r

natural circula*icr, the cctential for transients which w0ald result in FCRV c;enings,

the influence of con *r01 systems On plant tenaviOr, an: Octential voids and n0r-condensi:les in the crimary c0clant system. Westingneuse nas estimated tha* tne

.25 er react 0r year.

potential for PORV opening as a result of transients is accut There has Oeen on *he order of SC DORV cpenings

• hat have been experienced in this country on Westinghouse plants. There have not been any reportings of stuck-opened PCRVs on Westinghouse plants in this country. The Staff understands that it has been at least one incident of a PORV stuck opened on a Wastinghouse designed piant in another country. It was isolated in about three minutes. About one-third of the,.

PCRY openings reported in this coun*ry have been the resul* of an*ici;ated transien*s.

one-third resulted from pro 0lems with instruments and controls, and one-third resulte:

The Staff is currently from low pressure operation under water-solid conditions.

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• studying how the PCRV openings on Westinghouse plants can be minimized further.

There is a potential for. reducing PORY openings by increasing the number of scram initiators, but the NRt Staff is still reviewing the data and alternatives to improve the system. They will be addressed in a report.

Westinghouse analy:ed two classes of small breaks. One class is t c inches or smaller, which is about the size of the PORV, the otner creek size is larger than tw: inches where the core could be cooled without steam generators.

In response t:

a question by Mr. Michelson, Mr. Thadani said for the break size of two inches, steam generators will be needed for an order of ten minutes or so and the dryout time for Westinghouse stear generators ranges from 25 to 45 minutes without any breaks in the syster.

In response to a question from Dr. Carbon, Mr. Thadani said that for break sizes smaller than two inches and a situation where their steam generator is not available, the Staf# is addressing this in their analysis and it will be reported on in the forthcoming re;crt. The report is due out about tne end of the week.

Mr. Thadani continued by saying, in general, Westinghouse plants can be cooled down even if significant voids are developed in the primary system, 'Jestinghouse believes that they can go to reflux boiling phenomenon that could potentially uncover the core but bulk boiling and condensation would take place on the secondary as long as steam generator auxiliary feedwater flow up to two or three feet is maintained and the core can still continue to cool in that mode of operation. Mr. Michelson asked how the operator would knew the water level in the primary side. Mr. Ross replied that based on arbitrary steam break in

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the pressurizer of a CE plant that while the pressure is dropping, the level in the pressurizer would be rising and the operator would have difficulty in deciding the status of the plant so he would have to look at the primary coolant pressure and temperature. Mr. Michelson agreed this would be true 1372 279

TNI-2 Implications.

in the short-tern but d,isagreed that it would be true af ter a few minutes. Dr. Kerr

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corynented on a statement made by Mr. Thadani that operator instructions in the future need to be much more specific than they have been in general in the past.

Dr. Kerr said that he feels that it is d nportant to train the operators to handle unexpected transients but that instructions should not be so specific that operat:rs are told exactly what to do in responding to a situation.

It mignt be that a situa-tion arises when an operator would be afraid to use their own judgment because NEC or someone else would check against these specific rules and would critisize hir because the rules wee not being followed exactly.

In response to a question from Mr. Michelson regarding the pressure that would be needed in the presence of noncondensibles to maintain natural circulation, Mr. Thadani and Mr. Ross replied that a 31W analysis indicated that hydrogen would start to come out fast when the tem:erature reached to within 10-15 degrees of saturation. This is about 440 standard cubic feet of nonnal dissolved hydrogen whien is about 15-20 cubic feet at the pressure involved.

In Westinghouse plants the evolved hydrogen could block about a foot or two of pipe, but Westinghouse believes heat transfer can be maintained as long as there is some inventory on the secondary side, Mr. Thadani emphasized that these are only rough numbers provided by Westinghouse and no hard analysis has yet been made.

1372 280

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9-TMI-2 Implications Mr. Thadani continued by reviewing the information available about CE plants. The Staff has had one meetigg with CE to discuss natural circulation, calculations, and some comparisons of calculations with tests. Additional infantation will be provided On actual loss of off-site power occurrences and new procedures and con-siderations for ocerators in lignt of the TMI Accident. All CE lants exce:t Arkansas Nuclea-Ore, Unit 2 nave power 0:erated relie# valves and none o' tne plants nave recorted lif ting of PCP.V s as a result 7 of transients. The Staff is clanning :: est v:itn CE agaia :: discuss details of calculatices and analysis.

Dr. Ckrert aste: i' t e IRT cc:e, tnat Brockhaven Natier.al Laborata y nas cetained from C: :sstier En;ineering, can be used to simulate ancralous transients in CE pl ant s.

Mr.

H:iana, NRC Sta ", replied that the I; Ocde is si-ilar :: tne CE CESEC : de.

5:t :: es car be used for loss of feedwate-and ot er seconda y syste-traasiects Out neit e-nas the capability of looking at :hase change throughout tne syster, 5: ney could nct track tne TM: scenario.

Mr. holanan did not know if ne : de is being used currently to iearn more infernation a:0ut transien t.

• 4r. Ina:ani confirmed Mr. Michelson's observation that, in totn CE and Westingncuse plants, it is possible that a pressurizer could drain to the het leg after first being'neld u: in the pressurizer for a short period of tire.

Mr. Thacani saic :nat the N.RC Staf' nas not reached any firm conclusion on :nis but he believes it 00uld hapDen and the key is the words "significantly delayed" referring to the amount of time the steam generater water level would be neld up.

1372 281

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,, TMI-2 Implications NRC STAFF EVALUATION OF LONG-TER" POST ACCICENT CORE COOLING AT TMI C. B (Transcript Pages 149-130 -- Nc:e: Transcrip: Pages 121-135 are cut of place and snould :e put following Page 157)

Mr. Seriinger reviewed the Safe.ty Evaluation for the proposed transition to natural circu-latice an: cost-accident core c cling. The Conclusion of the recor is that natural circulation can be ac: m:lisned witn either one or twc steam genera: Ors operating in Or steamirg condition en tne seconda y side ;# the steam genera *:r.

eitner water-scii:

Mr. Berlinger sai t a; eve incuge t e : ant nas gcre :: natur al ci-cul atica, 9e inf:rmatier ir. ta.e cra#. re: rt :revice: some value t:,.:ne utilitj ar: tae NE: Sta

Considers the modifications being mace to One existing at the site. Tne re: r als F. : syste 3-: *-e

acks; c e :3.,

ea; re :.a. syster : sing desigrec art fatri:3te:.

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.cu': :e eking inro gn0ut One long-ter plant re::verj was es ecte: :: re~ air 'unt icani caring inis :eri::. Al erna e c: cling ecces, i' na* ural cie:ulatier :i: n::

0-i, ere als: stu:ie:. Tae NR: 5:a" investigate re#1;x :: cling anc rec 0m eace: n: nasti g tire t#ying :: 00:i-ize :Orciticas : ;se Tne ::re Oe:ris has bee" categ:ri:ed in tne cen*ral regi:n as more Or less this cde.

an inverte: pyramid tnat is postulated :: te a:Or ximately 5 #t. in ce: n extending out :: ne eri:neral regi0r.s O' the care. The NRC Staff tes: estimate c' core con-resistance factor) which figuration is a: cut 2CC times tne nominal "k" factor (ficw is e:uivalent := a oreximately 935 blockage. Natural circulation flow for 200 times Ncrmal natural the nominal "k' f actor is credicted to be about 231 lbs. per second.

circulation flow would be abcut 380 lbs. per seconc.

s.

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In rescense to questions from the Subcommittee members and consultants, Mr. Holahan and 'ir. Berlinger said that when the reacter coolant punp 1 A inadvertently tripped and rea-tor coolant pump *JA was started up, there were :hanges in core thermocouple readings indicating a redistribution of ficw and tre "k" factor is an average fact:r for ne core, and it stafed about the same although the-e was some local redistri:u-tion of material.

Mr. Welanan addec that even in natural circulati:n it 3 0:t...

that t9e-e is s;mt recistri:uti:n Of material Out One :re ave-age

'k" factor is about the same.

'tr. Se-iiage ::- 1.e: : ela::catir; on some c'.9e a::eriaace criteria for ;cir; int: r.a ;rai circula:i:-

e mest in:Ortant crit e-ia ere a li-i:3 tion c' 1:D-C'-

0 on in:cre t e :::.:les, a li-itation to remair at least 1 C ss:cocle: ir : e me, leg, an: t e ave age in: Ore 19erma:0uales re ain :elow satura-ion ::ncitiens.

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• i r. 3:ss reviewe: #:r : e Subcommittes :ne status cf system, ccmcenent, an:

i n s trume r.: c:e-a:ilit Tne tnree ressuri:er level instruments all rave failed. One react:r ::clant flow meter in ea:n loop 9as failed, and tue Of :ne reactor coclant pump seal pressure instruments have failed. There have also been failures in to n steam generator level indica: Ors, and it was tnis anc tne loss s#

pressari:er level indication :na: led to the decision :s proceed :: naturai convection on Fricay. At tne time of tne reactor coolant trip both steam generators were steaming Out inci:ations on tne 3 steam generator caused the licensee to isciate it arc currentif all heat rencvai is frce the A steam generat:r in tne steaming moce.

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In enswer to a question fror. Mr. Michelson, Mr. Ross said that feed flow was being changed on the B steam generator and since the licensee wanted to go tc water solid conditions es soon as possible, they decided to take the B steam generator off line.

At the present time, tnere are a::roxi: ately 425,0CC gallons c# aater in tne ::r-tainrent building ahi:- is at a level of a:0. 6 1/2 ft.

Tne : re inle, tem:erature 0

0 is about 2C5 F, and tne average c# the core exi: :ner ::u:les is a: cut 32 F rise, the peak exit the m:cou:le is accut 12,*F rise.

In ansae-t: a cues *' r :;. One Cnair an tencerning :~.e reasons f:r using ine R 3 system cri f as a last res '*., Cr. Mattson sait :~.at there was a ::ncern wi~.- :e leakage c tne RHR systee in tne auxiliary tuil:ing an: :nere's als t e poter.tial e

haza-: of han:lin; a 'lui: ::ntaining de:ris ani:n mi;-: acrse- : e leakage in :"e RSR syste'. t.re: er f a:::- i n:t as-tin; :: use RS: is :ne fa;; ina

ne fic.,

rate :nr:w;- :ne R. : syste-is a::r:ximately ecua'. :: tre fica ra.e ai:n na: ara' circulati:r.

A'te-sere r::ing by tne Chairman, Dr. 'ia:: son clari#ied tha: 9ere is some incication that RHR system leakage mignt have been nigner

• nan nor.al Orier to the acti:ert It is not known anetner One leakage was higner than :ne Tecn-Spec. limit or not.

DISCUSSICN WITH tiR. BRUCE WILSC? REGARDING CPERATCR LICENSING (Transcri; Pages 173-20g; Mr. Wilson stated that it is not a requirement for operators to attend simulater s;

training. Operat:rs that are trained on simulators experience a wide range of transients; the length of time at the simulator depends on wnether the training is in preparation for a license examination or requalification training.

In response 2

284

D**D "D N S.

we o

a TMI-2 Implicatier.s to a question frcm *he Cnairman, Mr. Wilson said tnat he *hinks 38W reactor opera *0t's are trained m0re on thermal hydraulics than cpera*ces from etner rea:*0r vendors.

He said tnat he routinely askr.ther questions about super heated, saturated and subccoled cor. itice:

In ansae- : a Ouestion from Dr. Lipinski, Mr. Wilser said that operat -s are routinely asked what tney woule de if a DORV valve stucked 00en er was leaking but he Cid nC*. k n 0 v. i# *Pis wal sce;ifi: ally in *ne *raiaing # 0r 00erators at Three Mll e li a".

I

• P t i O O

• I e

• .0 an:19e" Que5*iOr fr0- *he Chai" a", Dr. Ma*!s0F said tha *. Cgei n 015 :gi s 10ri.i tn 3a0CC k & Wil:0x. thef nad ike if a description of the 'Ordi*.i ~'

a *.raalitiOr fr0- for:ed-C0r.ve;* ice

• a na tg ra l c 09 s e c t i 0 r. v.'i *

• 0*ilir.; aal ~a:t ';

li~erseel s: *"at tne.' ~0.I develo: Or:Ced #es f0r follet.i ;

a smal' Octa-I:51 - O ' ~ ~ ~ l a " *. 3 " ~ i d e r. : ar: tne sainer aal ine nave n !.

H0we<e",

devel00Pe"; 0

• te a*a'y'.iCal requiremen*5 for 3;;* Or0:e:;rei are a Ore-re:gisite 10 tne "t*.;r"

• • "Cae' 0#

al' 35'.. rea

• r!

!" res:Crse *: a Ou ei*.i n f r 0.? tne Chair.ac.

Wils0r sai: !93 na.in; 00!c auxilia f fee:aate velves : lese: is a Vic<ia.<.

v.

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.c 4 <. n ~,. ; n. e.

e,v.-

o botn valves :1059: Crenta-ilj :.-in; tne Oerf0r aa:e Of 19e surveillar:e tests.

He Offeret : Or0vi:e tne in#0rmation at a later date.

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[ Transcript Pages 211-223)

.u;.

-s.

The ?G" S ta f # nas develocec a program for reviewing the 0ending CL 30Dlication reviews t9at will be Om0leted witnin tne next few months. Tne nex t six Olants are Westingneuse plants, t0*4rd tne end of the year tnere are two boilin; aa*er reactors anich will be ready for tneir o0erating license.

e 1372 283

D

}D *]D l'Y &

q w ju o Ju TMI-2 Implications A separate review grou: is studying Westinghouse reactors and developing a report on natural circulation, small break analysis, significance of and frequency of lifting of PORVs. There fi.a similar group doing the same thing for Com0ustion Engineering plants. 3ctn the utilities and the separate review grcups are re-viewing responses tc Bulletins 79-C5A and 79-C63 and they.ill be factoree int:

the reports being writtee - A!s: a management review grou: nas Oeen set u: to determine wha t T.atters sroul: be reconside e: for One coeratin-li:ense reviews,

however, no decision nas yet been made on tne li:ansing of any of the clants with cending CLs.

In -es: case :: a :vesti:r fre-Or Mark rega-cing e er; enc;.

planning, P<

5ea"s, N:~. Sta#f, sai:

t".a" as far as energe*:/ Olanning is Concern, in ordae :: ge*. a

e-ating 'icense, a plaat nas :: cr:ly witm ta,e ae.isices :

Apoendir E.

Taere is als: Regulat:r. Guice 1.lT revised in 1977 inere are ei t.e.

six or eig"t Dlants."Cse eme"gency clar.s 00m lf wit" Regulat:"y Guice I.l~l NRC Staff has n00 re;Ji#e: Oa (#itting Regulat:ry Gui:e 1.l7 to all Cf the 0:erating rea:t:-3. As a res.'t

1. t e ~ res "'le *slar: a::i:eet a : ta.irgs learae: f-:- it, a revision t: Regu'a t:ry Gui:e 1.1"I aill be made.

Dr. Ok eat aske: i# it would be practical to ask li ensees :: advise One NRC Staff if :neir current eme sea y :la" meets the a:crocciate Reg. Guide and what they tnink shculd be done in view of ne experience at Tncee Mile Island.

Mr. Sears replied tnat wnen t9e NRC Staff has tried tnis acor ach tney get a very, vague, general document. Professer Kerr commented that there is a significant difference new and Oerha s pec le rec 0gnize that emergency plans are very imocrtant.

s.

72 286

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J o o Ju TM1 2 Implications.

Dr. Siess comented tna; there are only a few states that have approved state emergency olans, and it seems difficult to improve emergency plans for a reactor

=.1 site wner there is no* an s;oreved sta*e plan. iie also commented that the emergency plan generalij Ola:es a lo more emphasis cc the local res;cnse than :ney do on a state res;0nse.

Mr. Sears res:endec :na: it is di'ficult to get concurrence on all enecklis: ite s ina: T.a s ce 00tained in cecer t have an 3:ar0ved state :lan. He c0 T 9"*.e"

• .*a*. ;earsf i v a ri a t ai 'la d a O' a

• si a e a:Ou

• I gM ar

• ae Bureau C #

Racici ;ical -sa'in and t e ~ivil Defense Organi:3 tion respencec a::r00riately t0

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s tne E. Sta## Or !99 5:e:i#i: i'.e s in :ne meeting 5:ne: le.

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witn regar: :: :lar s ari:- 3-e in :erati:-. 'i r. Sea-s res00nce: tna; all coerating rea:,0-5 ca 01, ai n A;;enci x E in order :: get an c;erating license.

The piants t a'. : n:t confor- :: Reg. 3ci:e 1.101 will be recuired to accrade tneir ere gency :lans :: ::c ly wi th Reg. Guide 1.1 1.

u.r. Sears acced

• hat the NRC Sta" regula-ly locks at regions deyond the LPZ and tne Chairman asked that ne NR: S ta f # Orovi:e Tcre details at a later date on how they will recuire licensees te comply ni n Reg. Guide 1.101.

s 87

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. J1 15 -

TMI-2 Implications II.A.I Procesal Recardir; Added Senier Ocerat:r in Control Rooms of S&W Reacters Mr. Matnis said tha* Ocone,e Units 2 & 3 will nave an additional reactor operator in and 19th of A ril the control room while trey continue operations througn the 12tn i

II.A.? NRC Reactica Ca:abili y and Role As it Delates :: Emercency 0: erat on Mr. Jcr:an saic tnat the. #irst tning that aas learne: from the inces "i' e Isl aa:

rm -icaticr.s f-:- ta.e li:erses, an: t r e *.: :

accident aas a nee: 0c more raci:

u manned on a 2a-ncur cuty : asis as weil as t e ir-Staff regional offices are nca cidert res::ase certer.

ers:ra'

ici:n tha* ir Or e' f;r tne NF: 5.a#* :: take 0.+-

Mr. Jor:3-en:-esse: "1i the 00eratic" c' a

'ar. i-ar e eagerty situati:", trey w0.1 ease 1: " ace a sta#-

trainec in tae ;1 art :: tae 53 e level as tre shif t su;ervisor, an: es #esis it is impra:tical for One NR'.

• take Over the c erati r 0 :ne s' a r t i n a n eme rgert,.

9*. Matais er:resse:

e 0:ini0n tra. t"e laat 00e5 no* be1 0r; :: *e Situatic".

NRC an: tnere# re in takin; Over 00erati0n O tre claat, tre *,R: Staf# P1;*t te liable

• law suits.

T9e Chairmar ex ressed cis C0ini:r that it woul: Se extre"el difficult for the NRC Sta## 00 have tne capability to take ove" each and every plant Hanauer commented tna* it is not reasona:ly Oro a:le in an emergency situation.

Dr.

that a government employees can d0 better operating tne plant tnan tne o erating In response to a Question fror. the Chairman, Mr. Mattson said that severai crew.

Suggestions have been offered concerning how NRC might have some kind o#master Ne one as yet nas C0mDuter in Bethesda

• hat monitors the status of each reat* r.

Dr. Siess asked thoughtfully gone over the suggestions that have been offered.

tnat at what point'in time could an NRC on-site crew done scrething to prevent damage Mr. Mattson replied that he feels most of the core damage was done in tne first hour or so after the pumps were turned off, so to prevent severe core damage

~ 72 288

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.:.... ~,.....;....

D * *

]D

1. lD'9' p' owN oNX.}Hs TMI-2 Implications.

the NRC Staff would have had to have someone there in the firs

• hour.

Mr. Mattson added in response to a question from the Chairman, it would be useful to have *he as-bui1* drawings en-nanc'in Bethesda for this kind of ar. incicent.

I I. B.1 Effects of Process tectrol System on Plant Safety Durin; Trarsierts Dr. Hanauer comreated

• hat non-safety ecuipment Can influence sa'ety in in0 nays:

(1) as an iritia: e

1. a* ever; anic s it Onen be c:ntrolle: :y sa'etj equi prer t,

anc (2) *ne managemea: Of the plant Ouring transients.

It was earlier tnougnt tra the Orovisicr of redundart sa#ety ecuiprent would a Comodate the PC'ential failure meces o' ner-sa'e: ec.i: e :.

Dr. Hanauer als: said that tne Trree "iie Islan:

accident : ::a:'

-:vi:ss an end ::

e ::licy ina t enij sa's:.-re' a.e: e:.i: e :

need :e revie e:.

-e a::e: tne c is c' nor-safety e;uip e : cr :lart cer'ormar:e during transiert is a to:i: ':r a great deal O' future investiga:ier Dr. r;e re conrente: that, i- : e future, cerna:s, instea: of talkin; a::a sa'e:j anc ::a-trol syste-s, 0-e a

'as e :: tal a::a: :: rte:' syste-s tnt: a-e :a:a:ie c' :: -

trolling clar: sa'e:f, aa a.e agreed witn Dr. Hanauer's : mments II.S.2 Frecuency

1. Chalierges to Sa'#ety Grade Systers Dr. Kere corrented that if COntPCI systems are made reliable, ther per9a:s tne safety system need not :e nearly sc reliable. One of tne rersons such a reliable safety system was needed in *Ne past was Oecause no at*ention was given to performance of control systems.

Dr. Mat

• son commented that ocening and :re:e* closing of DCP.V acuic not have challenged the ECC5. The opening and s*icking ocen of tne PORV makes it a.

small break 1.0CA that challenges the ECCS. In res:ense to a question from Dr. Siess, Dr. Mattson said tnat the Standard Review Plan dees not treat opening uc the primary system during a transient. There is a question as to whether or net the PCRV was a i.~ 72 289

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s. v.

n.... :n u.:.a.~.-

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gmm 7

g 9, 7

o o Ju o f

_ )l

. L TMI-2 Implications proper interpretation of the General Design Criteria when it was originally approved.

The question has not as yet been resolved.

In response to a cuestion from Mr. Michelsor

'ir. Mattson said that the :'ontr0l circuitry relating to the pCRV valve is non-seismic Cate;;rj i even thcug :ne valve itself is seismic Category 1 anc nat tne NR S ta f' is studying this situatica.

In res'::"s e 10 a Cuestior 'r:

t e C

• a i r-a r, Dr. Hanauer sai: :na; for a S&'.i plart tnere are sli gat'y :.e ta: fee: ater transients per reat Or jear. C ::ustion Engineerir; and Westingacuse PW:- ex:erience about 1 1/2 feedwater transients per year.

In the 35.. de:i;- : e-3 a.3 :33- :-ree irstaa:es wnen the 20:.7 nas stack ::er ca: c' a: r:ri-Tatelj 'i: 3:1 a.' :" I :# : e 00:'l e NR: Sta " has arrive: a t relia:ili t./ 'i;;re for tae es'ia: '

1. tre auxiliary fee:aater pa : failing :: s:3-manuall.

O' a:Pr:ri ate'..

ir 10:. Entra:01 a ti n; tri s #urtner, Dr. Hanauer said that Mr. Cent:t was tryi ; :: :a': 13:3 :~e er::a:ility of stea genera:Or cryou; aac that #:r :-= :nree 00:ree '.'- :s : e :r::a::,

as scre e-e :e: ee-I ard 2 :er yea-5 : 1 in 22 :e-year, ar: "

er :

a.aracte-ize: it as 1 in 10 :er year. The Cnairman suggeste:

that ne e na: u e : r'ssi:n ove inis num:e, particula-ly witr a 'ir. McCa rtr wne is t*e hea: c' the ajority party in the assem:1y in the state of California, and that the N:.: Sta" sncul: :e careful to make clear exactly anat it is tney were descricing.

II.B.3 adecua:y f Water Inventory in Once-thr:ugn Steam Generators Dr. Mattson ::mented that tnere is long-term question on whether B&W once-incougn stea generators can be o:erated with a higner water level than they have been ocerated in the past. A higher water level in the steam generator would result in less sucer heat.

1372 290

-....-....~.

l l

l

, -f ll T'i!-2 Implications.

II.B.a Shared Facilities - Degraded Condition; Dr. Mattson commented that he does not tnink there were any safety questions relayed by tne snared facilities at inree Mile Island.

In response t: a question from the Cnai an, Dr. Mattson said tna; it would have been an awkward situation had tne t.c T": units sharec tne auxiliary buildinc.

In response to a cuestion fec-

"r. "i: e'scr, Dr. Mattson sai: :nat wnea 00: nee finis es i;s mccificatiers nef w- 'l have e:e: -i; fee:~ater Ou.:s ':r ea:* uni: :: :- vi ce f:- *e:.ndar:;. an: cive-si..

al thcug h he did nc* know if tne electric-driven pum:s w:uld be snared amon-the units.

II.E.5 E'.d-:- e-ta' O.!'i'ica-i:-s c' *.: -Sa'e:- Grace I:ui: +--

Dr. Ma.:s: ::- ente: tra. tre $;a : in,s tr.3, --is is a ygr, 3r :r:ar;., :,

and di

be s Jd in-4: Very closel In res:Onse O 3 cuestice #r0F Dr. Li:insk',

Dr. Mat:s: sfi:

a. sesera'

rce: s regar:irg cualifi:Stiors C ncn-sa'e!,

e"ui 7 e.

a.e :ee s;; geste:, Ore w: '.: Os :: ex;ec: t e lis:

1. sa#et gra:i insteu e-tati:- a-: ar::ner *0ul

e t0 3:0 a anoiner grade 0 safety ecui: Pen,

Saj " lass I.*,

nCasse, n nin- # ire. ras beea done yet.

I:.2.5 Envir amental Quali'ita tions c' Ecui: ment in Ncn-Sa'e:j Buildi ngs Dr. Mattson repliec :na tnere are cuestions about the use of safety equipment in non-sa'ety buildings but the NRO Staff has not looked at them yet.

Dr. Hanauer c:mmente: tna: ne re-ninking :eing done regarding decay heat removal systems,

antici:atory scrams, instrumentation systems, and equipment cualification raises questions in all piants not just 5&W plants.

l372 29I

~

[) O 7

rt.

rl 3]I b

i ld i

TMI-2 Implications 20 -

II.B.8 Pressurizer Connection to the primary Syste-Dr. Mattson said that it is not clear that this is an im:ortant :arameter in re.;

ing tne sensitivity of 313 re, actors to upset conditions in the secondary.

It is, however, of long-term interest in standard designs for the future.

Dr. Plesse commented tha t a small rise over a 1:ng run in the connection between the pressurizer anc :ne het le-could give rise :: a seal just like a maneneter seal.

He was interested ir. finding out how a :Jratel. !ne Corne:*1ng line is Iace.

Dr. Lipinski aske: if :ne NRC Sta was exar.ining tne desiratilit/ for a separate dedicated mea re :.a' syster :na: coes nc: involse majcr plant ccm:Oreets.

A'ter sore re:;i ; Cr "a::s: re::iec tna ae cid ne: kn:. :ns arsoer :: t.e :uestion but ir :.e

-ree " :s :s;ae: a:: ice : i: was :ne snai; rear icss-:f-::: ar a :icent tna was nc. Oea': uitn :re:erlj.

In ansaer :: a questier fr:

ne Chairraa, Dr. *at:scr. sai: :na: :ne NR Staf' mas net re:iied t: all tne vari:us cral an:

writtet re:Or.ren:ations tne A::5 has giver :: :ne Co--issier, noweve, :ne NR: 5:a

is aware :'

e a'

an: :nej are taxing :ne-inte ::rsi:erati:-

II.A.: Techni:al Ea:ka: at C:erating Utility an:

I;. A.s Te:trica' 53:*a: :: 0:erau ng utilij Dr. Mattson sai: :nat the NRC Staff is going to icok at the cuestion of tecnnical back;: at the ::erating utility for conducting sa'ety c: era icn over :ne life c' the lant, and tne NFC Staf' is also studying ne need for tne NDC Staff to have greater assurance and revide earlier cacability to the licensee in the early stages of an ac:icent.

.s.

The Chairman asked Dr. Mattson how one should approach what constitutes suitable technical backup, he replied that important elements include noise analysts with more sognisticated diagncstic ecuipment than normally available, principle NRC e

.......w>.......

2 TMI-2 Imoli cations Staf f decision makers and technical staf' ready for immedia*e mobilization, basic tecanical information about each of tne plants, and better preparation to cope with

.v He added that the organi:ation of an emergency emergency situations by tne licensee.

Mr. Ray force or swat team cy the utilities should be strongly suggestec.

tast added that not a'i utilities wili staf# themselves to take acs antage of c:erating experience, inej rely toc nea.iij or e-: t ;ec t-engi aee-fi-s II.A.6 Rcle of Cnsite ?m: Insce:t:rs_

Dr. Siess 3*ie: i' nere is a #eelir; inat tne 0:erators at T*.ree Vile Island are less ael.-trai-e: t a-tacse at ctae-rea:::-s aa.: is ina: somet-ia; taa: a resideat inspect:" w ; : e a:Ie *: 3 s ; e" *a i " Oe t*.E'

a*

!"' ug' r:;tirt i* ire:*.i r?

- J#:a' Or:;ra-gi,es 3 : e ci-e:t ::se-v ation O' licensee replie: trat t e resi:e**. insce:: r ac*ivities 3":

elie.es it a id :# vice a be*ter 0 * "tJnity.

In res:Onse : a remark t.a*.

• e resi: eat irs:ect:"; aill nave the same GuaIi-f ror D. S i e s ;, "- JO *:a a 30:e:

ficati;as as a se-i:- 0: erit:- li:erse al-c;;- taey :r'; te as kncwie:gea:le :#

te car *icu'ar clar*. 0: era *i r as **e

Iart 0

e#at:rs, nas an icea of 50. efeective tne onsite ar:

Mr. Ray asked Mr. Jor an if tne Na". Staf#

Mr. J0rdan replied that a review of offsite review and audit ::r:-ittees function.

eieren* of tne ins 0ection the intensity and frequency o# audi*s perform 9c is new aa and audit committees are new generally performing effectively program. The review but pr:blems have been identified as enfcreement mat *ers in *ne ins ection Oregram.

II.A.7 Clean-u: procedures and Ecui: ment Mr. Jordan said that tnere was little or no preparation for this size of clean-up and tnere are other plarts in better situaticns for

• hat kind of work than Three De cone in nis area The NRC Staf' has not yet decided if mere shool Mile Island.

i,r/?

293 for the future.

J TMI-2 Implications The Chairman reminded the Subcomittee members and consultants that the Subcomittee must make some specific recumendations to the full Comittee. He asked the Subcom-mittee members to reflect,or; how the Subcommittee should make these recommenda* ions,

~

and he asked the Subcomittee to think about what items on *ne meeting schedule should be deleted from the discussions because of a lack of time.

Dr. Siess suggested *.nat tne Subcommittee try to procose a program for future full Comnittee agendas whicn say what are the lessons learned 50 far, what needs to be cone by the NRC Staff, by *ne ACRS, are by incustry. 79e Corrit*ee shculd tnen concentrate on..at the ACRS mign*

do.

Dr. Car en acce: tnere wil' have t De cricrities on n'.at the fall Committee can do because the Three ile Island accident s*udy involves a Ic! c' additi0nal work by the Cormittee.

The Chair aa suggested inat tae Su:: nmi ttee snculd take u: i te- ::.3.1), "Ces i;"

Sasis f0" Cst-*-::ide"! -sa* Rem Val Syste*!,

f r Current 0:eratia.; rea *.;

5.

't asked *ne NE: S*af# i ' t r e,.

,l a a,

re-examine One design basii 0e Oost-at ice"*.

heat removal syste 3.

Dr. Mattson re: lied that the Sta'f Oces intan

re-examine tne design basis and 1 ck at their finw capacity neat renova' ca:a:ity anc seis.-i:

cesi;r as well as envir:n-' ental : alificatice of tae e;si: rent act sensing instrume-ts tnat are use in tne system, an also tne ca: ability :: :: maintecance er one loc:

while tne other loc: is in coerati:n.

II.B.11 Containment Isol ation Dr. Mattson said that the NRC Staf' is studying the inconsis*ency in containment isola

• ion signals that are present fr0m plant-to-plant. He said that the.1RC Staf#

did nct understand that the violation of containment isolation had occurred at Three Mile Island was possiale wnen the apolication was reviewed.

i*

I I. B.12 Vents on Reactor Pressure Vessel and System Hign points Dr. Mattson said that it seems reasonable to require these vents on plan *s ready to start up and/or operating plants at the next refueling.

Dr. Kerr asked how 1372 294

.w.

1. '*]D C DW N

D

&& du b$

5 TMI-2 Implications difficult it would be for piarts to provice this vent, Dr. M.attson replied tnat he thinks there are ways to do it on :ncs plants thr0ugn penetrations that are new capped off-

'277 295

)J

).

s D**}D *]D ]Y$

o o Ju o Ju SU Inl.m May 1, 1979 Cr. Okrent reconvened the meeting at 8:30 A. M.

The Subcomittee brie #1y discussed future actions which the Committee ray want to take.

If the Cemittee decides te carticloate er is asked to partici; ate in a review of the shutdown S&k plants, a mode of operatien will have to be selected.

Dr. Okrent requested the ACRS Staff tc collect rucn detailed information as is available regarding each of the issues a:

raisec in the shutdewn orde-s.

It was mentioned that the Comission has alreacy askec for the Cor:-ittee's thouchts on additional changes or fixes whien rignt be needed.

A ciscussion of the incident at TE deveicced.

The Subccc:-ittee seemed to agree tnat even if tre auxiliary feedwater sy; tem had ocerated fc11cwine the less of the main feecwater system, the PCRV would have ocened. As a result of tne stuck coen relief valve, throttling back the high pressure make-uc pumo and opening the letdown lines, the onset of a water inventory crisis may have been accelerated. Throttling back the high-pressure make-uo pumes and opening a steam generator letdown line were probably a response by the coerator to adjust pressurizer water level to the proper range.

A short discussion of operating procedures at TMI was held.

Itwasnote[

that the operator could have had sorne difficulty in assessing the situation.

However, there was no reason why the operator would have been reluctant to close the PORV block valve.

~.. 2 d b

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b 2-The NRC Staff noted that it is very difficult to say what the TMI operators might have dona differently if the auxiliary feedwater valves had not been closed. The Staff noted it was quite likely that the PORV would have opened, and quite likely it would have stuck ocen. But, the fact that the auxiliary feecwater system was not available created additional distractions (stear generators olewing dry, leak indication in the S stear generator, etc.) which might have made recognition of a stuck open PCRV more difficult.

The Staff stressed tnis was all speculation.

Dr. Carten discussed the t :ic of future actions by the ACES.

He excressed ti e cesire to see the T"I-2 Accident Im lications Subcorrittee develop a course of action to direct the full Corrittee and various Subcomittees.

The directi0n shoulc consist of tocics for review anc priorities.

The Subcc rittee ciscussec tne topic of water level instrumentation in the react:r cressure vessel.

Dr. Hanauer of the NRC Staff noted this is one cf the most important subjects the Staff has for long-ter study.

There is no such instrument now, nor hr.s the Staff (or.e a sicnificant amount of short-term work towards developing one.

Such an instrument seems feasible in principle, but other questions such as, "would a RPV level instrument introduce additional problems?", needs to be addressed.

Dr. Hanauer :nentioned even more far reaching ideas such as, an overall 6

primary system inventory instrument and a system energy content instrument.

These ideas could deserve technical study.

1372 2H

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3 The subject of water level in the containment was introduced.

It was noted that the:5taff has not devoted much time to this topic. One problem area for such a monitor is the intense radiation field in which it might have to perform.

!!r. Ray asked abcut the current inventory of water within tre containment.

He note: tae"9 hat been several different reports on the arount of water witnin containment.

Dr. Mattson noted that an atterpt to measure the centain en: water level is underway at tne site. There had been no bi:

5;ill er acditicn to the containrent water inventory to his knowledge.

The Subconrittee discussed the tecic of the indication of the status of valves and other cceconents.

Dr. Hanacer noted tnis area recuired study.

Additional indication available to the oceratcr may be useful, but cautioned tnat tne ootential for everkill exists.

Dr. Okrent introduced the topic of short-term corouter assistance to the He defined "short-term" as something which could be implemnted o;e-atsr.

in the near future. The Staff has no program to lock into th1s area.

The corrent was made that the computer at TMI-2 was not as heloful as it could have been. This subject has the potential to become a research project for NRC or EPRI.

The next tcoic introduced was the use of flow meters in the hot or cold 'e'c of the primary systern.

None of the flow meters currently in use could measure flcws associated with natural circulation. The Subconmittee noted it is important to give an operator as much unambiguous information as 1372 298

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possible, that does not require inter pretations or ji.xdgement on the par t o.f. an operator. A flow meter located in the primary system could be a useful devi:e. Dt. Siess cautioned against giving the opet atot too much infor nation and cited the need for man-m.achine intei action studies.

A discuss.-.f the adequacy of pr ocedu es f t na ur al

ula:10-cocling 10ck place. Dt. Mattson noted that foi the condition of single-;i.ase not.al natut al circulation r esulting ft:m a less of off-s::e pr.,w: and rear:.r st ip, a fair a: :.u.: is k..ow..

Ocer a rs ar e

a ned a.i syste-s designed for suc". a si tua. :r. A question at ises f;i natur al cit rulation that occur s in an ac:: den situa-ion.

In an ace: den situa:1,n, natut al cir :u a-ion

.a. include :citiple pr.ase fic.c. Ocet at:1 s.af n:,: have tee instr ucted as to how i ea : s sue. a s::ua:ic...

Eher gency procedut es fet such a s;;ua ::n in B&,-

pla.:s wte reques ed :: te developed ever the nex: :.c :: theee we<s.

Ci. CK: ent cited tne need for additional investigations in the area of natural circulation cooling. As an exanple, he ;csed the question of a W1 ECCS injecting cold water frec the top of :he vessel. Could this modify or interrup the nor na1 flow cf natura1 circulat:en? Could Y

the nitrogen system associated with the W: - ECCS malfunction and introduce noncendensibles into the trimary system?

• hat effect.culd a

this have on natural circulation cooling?

1372 299

The Succon:.i::ee took up the topic of the pt essui e-spike in the conta irce.ad,.

It is believed to have been caused by a local hydtogen explosion. The only facts in de matter ate da one ptessure in-d :ator in the centaircent read as high as 2S psi.

It is awamed that at one pint det ing the accident ther e was enough hydrogen to cause a. explosi

,r..

Cutten: estima:es at e dat between 30 and 40 cet ce.: Of the core oxid::ed. A the present time, ther e is no r eason to dout:

ner e was a hydr ogen explosion.

is one wa, :: r eccneile the pr ese :

/dr agen concenti at::n with the high degt se Of exida:::. the Staii

= t e.:.; cel:e.es :00'< place in de core.

te pr essur e spi <' e did actuate de contaim.ent spr ays.

Se contain:en:

had isciated (at 4 psi), W.id was t oughly 5 hcut s int: de ac:: den:.

Se pt essa e spi <e occur t ed 9 hout s inic de a :: den..

is :elieved tha: :ne scd:r. hydr:xide (a spt ay additive; actuated wid the spr ay.

Se Suberci::ee discussed how to pursue rea :ot cpetating experience.

Se ACRS 2R Subereittee was cited as a test mechanism to see t.at can ce learned from ERs.

r. Mattson mentioned that the scre notacle 2Rs at e elevated to de status of abnetmal occut rence rep:r:s and pr ovided to Congress. Abnormal Occurrence re,:x:,rts are cercughly disse-inated witnin the Staff.

Dr. Okrent noted that in addition to de GR Subeccmittee, the ACRS may need to develop other mechanis?.s for dealing wi 2 ERs a.-d oper-ating experience in general. He noted that ACRS concerns -hich -ere T

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. raised a numb,a4 of years ago in licensing reviews in soce cases are finding their way into I.ERs.

He emphasized a better system for incot; orating operating exper f ence and r e-view items is needed.

Or. She.ccr discussed.he subje:: of the apptopt: ate de :." of knowledge recuit ed by the NRC Staff. C:. Shewmon mentioned the ar ea of che s:t y t e' ating to oxycen-hydrogen reconcination r.d pi imat y sys e water chenis ty as an exa ple. He wished to k.ow how ex ertise 1.- :.e Staff is organized. 7. Ma s n noted :nat i-ar eas wher e weae. esses ar e ap at en:, Staff excer tise is br oadened.

He noted ne Staff nad good expet tise a.d consultation ir the at ea of che :str thr oughout the a::iden: at N1.

He did ncte, however,

ina conce: r r aised over the explosive ;ctential of the hydt oge-bu::ble inside One vessel was undeserved.

Ray noted that now euld be a good time to push for the expeditious wt.

resolution of generic items. A new effort to resolve them should be mad e.

Ot. Okt en noted that he ttx:ught there had not been enough studies of various pestulated scenarios following a violation of the single

.g failure criterion. Such scenarios should be followed to see if gu can recover from them with existing equipent. "esign impt ovenents which could mitigate such situations may result from these stt. dies.

~2 301

0 1 0

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~ ~ n MUM-d Dr. Siess noted that a reexamination of the pt iorities placed He felt it would be in-on genei ic iEems may be worthwhile.

d :: the Staff's teresting to see if additional itecs might be afde list of 19 generic safety issues (NA% 0510, W.ich was sent to as a iesult of the ?~ accident.

Congtess) ite-s cocid be in the resolution Of genei::

Industry inv'.,1vecent.

S;ch industry assistance to the Staff could help ::

valaa.ne.

exced:.e -he i esclati:n Of :enet ic ite-s.

suggestions f2 x the Sacconn:::ee On ways ::

?. CK: en as<ed ft cocid be made to re fall 00--

pr oceed and t ec:rrendations tha:

of sucgestions:

Sless resp ded with a nc.te:

m:--ee.

confirn in wt iting the et al recx-enda-W.e Cm-ittee shoulu 1.

ens made en.N:t il l'.

~he Cormi::ee should establisn procedut es for handling 0;et ninc 1.

applications.

license applications and construction per ni:

i es Assignments should be made to the various ACRS generic subc 3.

ident.

to work on var ious aspects arisirq fr:rn the E acc Dcamples ineld ed:

ECOS subcommittee - lock at small-br eak LOCAs (a)

Cper ating Reactors - study natural circulation and ma.-

(b) machine interfaces. Also study plant operations review cern-mittees, incident evaluation and respnse, inservice i.y spection and testi:x; could be censidered.

1372 302

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Plant art angements - study the uses of nonsafety grade equi.pment.

(d; te radiological effe::s and site evalua::en suberci :ee stMy p:st-a: iden monitet ing, emet gency plans, and s :ing =c11:y.

te Tne t ese :t saf ety i esear:n suber :::ee :11 need :: lock at a num:er of at eas.

' f '.

T.e Class 9 A: ident Scber,mi tee - r.ay lock a: emer gency a-5 :ontingency plan-ing.

t; Tne single-f a;.ut e et itet ion s cr. :::ee and de i el:a::1::y and pt bab:'istic assessmen suber.it:ee - s: ri,. :ne fr e-quency of :na11enges ::. vaiicus sys ems, and the use f e sing;e fallut e et ::et i:n ver sus t elia:il::y evaluations.

Ci. Siess concluded -.a: many of the isssues at ising ft r the N' a::: den:.ay be more effectively reviewed _

• Saccor-ittees, than by the Cor at::ee as a whole.

0:. Ckrent suggested that the topics listed in the schedule be d:-

vided ancn; various subconmittees. Some topics may be shar ed rerg succcomittees or grouped to reduce the nunter of subecc=1::ee mee:ings requited. Cthet topi:s may require a recreendation from the Crnit:ee ;.

that studies be conducted arx! not require subermittee meetings. De Com.ittee's timing on issues may have to be paced some*.at to the Staff's 1372 3'03

Df}I

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pace. Dt. Okt en: alsc roted the Cor.mittee will have to give attentd$n to the future operation of S&W plants in the months aheai.

By the June ACRS meeting,.Mi. Michelson will attempt to et e-par e his cw. Chi onology cf the events a: ? '.:.

Mt. Maris no:ed i =ay be instructive for scme of the Com-nittee me-ber s s visi the B&W simulatet in :.y.chbutg, Va.

? :s w i d give Com.mittee mer.bers a feel for scme of :he tra:.:q

lant 0;er a:;r s e eive.

Prof. Kert rc:ed that a r eview of coera ot qualift:a.icns, sta:ning, licensing and re:jalif::ations may te of intet es..

He noted :: wuld e Of interes: :c determine how the syste-of licensine ard exr-i.-

ation is kept.y._ to-da e.

It may also be useful tc cry and devise a me-hed to measur e me effe::iveness of :ne oper atot licensing syste.

Ot. Ckt en noted the need for better centingency measut es.

He cited schedule topic 1:.: which gives a few examples of contingency measures.

Dr. Carbon mentioned the fact that the ACRS has already rec:rar. ended that there be instrunents to follow the course of a serious acciden..

i.

He noted it may be beneficial to reccccend analytical stadies to follow the cout se of serious accidents. Such studies ceuld act as maps if a serious accident were to occur and better pt epare those involved for the p:ssible direction such an accident could take.

1372 304

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Dr. Carbon ut ged the ACRS look at the broadet pnilosophi:al appicaches t;. safety design.

A reevaluation of the single failut e et itet ion e.ay be in ot det. Passive safe y syster.s, he noted, may desetve fut thet attention.

In the at ea of isk analysis, it was nc ed.na: if the conse-quences fi or a si.gle f ailut e at e h:g." enoug"., per haps a tv.

f ailui e et itet ion should ce used. Such a tw failute critetion wuld impr ove the sys er.s t e'iability.

t. Oste.

as<ai Cis. Meti a-d Siess :s :t. 3.d piep.ete ge e s_

gu: dance he the 7'.:-2 Accident !.?.pli:ations Set:or. :::ee and f.!

tne full Cor.-ittee.

C:het mec::et s pt esen. wet e as<ed to wt ite individua'. dis;r.,sitions c.c schedule 1: ems or other :: ems they feel a t e sa ' : e..: i

• .e i t at us :f intet est.

Regat di.; G eviews, it was noted tha. reviews Oculd. axe a specifi apprca:h and address events whi:h direc:1y relate to the ?d:

acciden. On the othet hand, the Com.ittee could address bicader issues, such as, emergency planning and contingency plans as a re-sult of 'N:, although they are not related to a specif:: type of accident.

2e possibility of a ::ero power critical license for Sequoyah was raised. Currently the Staff has no pcsition on such an item and its usefulness is questionable. ?ae possibility of additional instrtr.entation for Sequoyah was raised.

Se meeting was adjourned at 3:00 P.M. to be reconvened at 8:30 A.M. on May 9, 1979.

1377 30-3

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O h

h If AD HOC SUBCOMMITTEE Die THE THREE MILE ISLAND NUCLEAR STATI0d ViiIT 2 3.

ACCIDENT IMPLICATIO::S Tr.IRD CAY, MAY 9, 1979 rir. Grimes fre, ne Civisien Of 0:erating React:rs reviewe: :ne current status of TX.-E.

nea; was Oeing rencve: fr:r :ne primary system uncer natural circulation :: tne A s team genera:Or.

The primary sice pressure was ceing cro::e: frer 300 :si to SCO psi and was at 775 :si.

The highes:

taerm:::.:le rea: n; measure: IEC F, a: cut four in:nes a::ve ne center cf U

.R ::".

'o:ine releases measure: cn su::lemen:al filters anien nave ceen installed are near : a minimur cete::a le level.

Envi ronmental c'fsi te reasurerents are at :a sgr:. : ievels.

Ra:iation levels inside One ::ntainmen are in :ne neign:cen::: Of a few nuncre: R/nr.

Tne ce:a/ nea: remcval system is being u: grace.

TV cameras nave :een in-stalle: for rem;;e leakage menitoring. Acceler: meters nave been installe:

cn tne pumps for remote vibration determination. The B loop has been leak testec, one gasket neecs to be replaced.

Contain en: sure level measure-ments are cianne. Ine a s team generator locc is expected to be availacle in aceut one week.

Roger Boyd cescricec tne current licensing aporcacn to 0:erating licenses in lign: of tne Tnree Mile Islanc Accicent. He noted tne current eff r:s in culletin preparation and review and feecwater transient assessment.

s Special studies are also being c nducted en operator training, emergency respense and erergency planning. He described the general patn of the review and noted there was no special organization set up to deal exclusively with pending OLs.

kb

Om o D D

- dy3 TMI-2 m

4/9/79..

Mr. Boyd noted tna; stre::n power increases are not being deferred. The Millstone-2 stretch pewer increase is scheduled for Connittee review in June.

A list of pencing OLs was given. Listed aere plants witn ACRS re: orts, onese wita ACRS revie. :endin, and cine OLs. The ex:ectec construction ccm:letion date ae s giver f0- ea:-. Tnose plaats nearint :ne erd :#

cons: actice nave :een aske: :: res:en: :: tae :5E tulistins.

Inf:rratier deve10:ed as a res 1: c' T": aill

= fact: red"in : an SER su::leren: alen:

.itn the resolutice of c ec Sta#' review items for tnase plants with OLs

r C.. re r

:se ve: tr.at tre Staff sneuld give care' i atte. i:- :: ;ia-:s wnien nave nc ye: :een sta te: :: see if certain me:ifica-icrs whi:n migr:

resait f r:r ne TM: ex:erience coulc ce im:le er. ed ere easil, A: :ne mcrer: :ne 5:aff :lans :: im lerent A'Ri re :rrendations On new CLs, :: :ne exter: :ne ::- ': tee tr. inks necessary an: :ractical :e':re plants ;; : ;cwer. Tnere is n ian y ne Staff f:r an A*R5 re-revie<.

1. plants aitn ACR5 lL letters unless ne Committee re;uests a re-reviev.,

as a guess, Mr. Scyd did not think tna: Secuoyan wculd be issued an OL in July, tne ex:ecte: : nstruction com letion date.

Mr. Scyc conciuced witn a lock at tne future ACRS scnedule.

?-

Dr. Mattson noted there was no new information on the Three Mile Island chronology He did note that I&E currently intends to issue two preliminary recorts en the results of tneir investigations, one in mid-May and anctner in mid-June.

It was noted that Warren Minners of the Staff is trying to put together a chronalegy of wnat happened at TMI, using a cause and effect ty;e aporcach.

'377 507 i

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5/9/79 g The Staff plan ed to out together a package of infor-a:icn containing letter responses to StaffIncerns from utilities relating to the voluntary shutdewn of B&W olants, signed confirmatory shutdown letters, and analyses submitted by Bt.. A Oriefing was planned to give tne Committee an overview of tne review werk unceraay en the snutdown 3&W plants.

Alse to be included were c:cies of ne A:ril 25, 1979 JRR Status Report to :ne C:crissi:n er Feedwater Transients.

Cecies of tne Staff's evaluation of tne long-term pcst-at:icent coolin; at inree vile Islan: ae re di stri:..:d.

Tne recort incluces a sectier cc ::-e c::la:ility nrau;- natural circulaticn, a secti:n en :ne status c' tre a se::i:n ces:-i:ing lar;-ter syster mccifi:ati rs :: r:r::s ce,a:

c clic;.

The Sub Or-i::ee reviewed Orc:csals for ACRS activities in lign cf :ne TM:-2 ac:icen:.

Dr. Kerr :egan witn a list of suggestions. He ma:e One scin. :ne C:r-1::ee shculd conce-trate On icn;-terr ac*ivities ra:ner :na-snce:- e ma tte-s.

re felt tne Ccrrittee snould nc mare an e#f:- ::

recesign all react:rs :: resist ne T".*-2 ty:e of accident, if such an effort is necessary, it snculd :e ac:Ortiisi.2j in th: near term by a cor:eter.: gr u of full-time cesign engineers. He noted The Committee snould give careful and icng-term attentien to the training and licensing process of operators.

A careful and long-term examination may be aporcpriate to study the criteria The reli-for separating systems into safety and nonsafety grade classes.

acility of nonsafety grace systems may warrant i:Trevement.

Finally, Dr. Kerr noted it may be accr0eriate to reassess tne priorities given to various cen-tributors to serious accidents in lignt of the accumulation of ex;erience and analytical studies whien have teen performed since the large LOCA was picked

as the incident of egnasis.

Mr. Micnelsen discussed his ideas for the scope of work in the short-term.

He noted it is necessary to learn in a timely fashion what hacoened at Three An accurate chronology that gives a definitive picture of :ne Mile Islanc.

1372 508

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ddao 11/AL TMI-2 5/9/79 4

incident is net:ssary. c:a notec I& 's plans to release a preliminary in-vestigative re;;crt i.1 mic-May. Mr. Micnelson tnought it was important to cevelc: an aceouat1r'ancerstanding of very small break less of coolant accidents.

ne tncugnt additional infoemation is needed in the way of natural circulatien benavior and reliacility. He noted the need to develc: information on the trar;ient cehavior of main and auxiliary feecwater systems. C erator training anc tne cuality of c erating Orocedures were cited as areas which deserve care-fel attention.

Finally, he felt tne subject of vessel level indicati:n recuire:

1 r e: 3:e atienti:-

~i-::c ga.e a lis; of Or::: sed re::=en::ations.

re ::is:ussed tne :::ic c'

ass.a sa'e:. systrs ari:n 0:e-a:e regar less c' c erator acticn or ecui: e -

fail.re. ce 5:e:if1:aily n :e: attention te given :: ::ntainment syste s.

A se::n. :::': ncte: ::ern: training.

-e singled : t tne ualifications

1. :ne senice :: erat:r en site rescensi le for :ne :lants c;eration, su:n as, a shif t sa:en s:r.

.-e acnce re: if an a::re:1a:le u:;rading of :ni

ersens cualific'

1:ns isc' t a::r::ri ate.

Dr. ;.rten 's tl.i rc :::i: sug;es te: tn a: :ne "CRS

09s' er ' rgi"; :na*. stu0' as :e CarriEC out ';r a idents wni!" gC Dey:nd ne Cc.

-e "el' eve: ar. i m::c r* an * ::a r* o f *.n i s wo ul 0 D e *C 9cor00 rate as much Or ::a:ility analysis as Oractica', anc to again rec 0xend instrumentati:n 4 i ns ta lle: : f ell ev. tne course of a bey 0nd design casis a :i:ent. iiis fina!

tnougn: was tnat tne ACRS shoulc try and put mest of its incugnts in writing.

Part II of Dr. Carton's suggestions dealt with the ACRS tak'ng actions on its cwn. He suggested the Cem.ittee review its annual report to Congress on Rf R an i ts generi items list to adjust pr'orities and take such actions as n<t ces-sary to accomplish hign priority items en a timely basis.

e suggested more time be devoted to advice fecm operating grou::s at user o'rganizations.

Dr.

Carben suggested ferming a team of fellcws, consultants, and staff to do independent studies of tnermal hydraulic aspects of PWRs and SWRs to see if they can observe prcblem areas that have been overlocked. He noted more attention might be needed in the area of sabotage. A reevaluation of tne 1372 309

THI-2 5/9/79.

single-failure criterien may be in orcer. A long term technical review of the entire regulatiry system lasting one year may prove beneficial.

Mr. Levine gave a briefing en implicatiens of tne Three Mile Island Unit-2 accident as tney relate to reactor safety researen.

One area whien is being addressec is resear:n on :ne recovery of Three Mile Island from the accident.

This prograc is cesignec to address six large areas wnicn relate prin:ically to tnings ina ougn: t: be ::ce :: understand wna na::enec and t: get data that aculc c:nerwise be lost.

The six areas wnicn a e currently planned t:

De addresfec are:

1.

C:rs Examinat4:n 2.

rina ry Sys te an: C clan: Analysis 3.

E 5: ear Generat:r Failure Examination C:n:sinre : ( Auxiliary Building toc) Examina:icn 5.

Camage t: electrical corpenents and instrurents (ca:ie c:nne:::rs, ccxes, etc., particularly ECC5 relate:)

6.

Total Fissi:n :codu:: Material Balance.

Mr. Levine als: r.cte : :na a recuest for an amendment c :ne FY-30 RES bucge:

will e ser.: :: :ne Commission.

It will include re:uests for funes :: : ver TM;-2 recove ry resear:n in ava tion :: other areas suggested cy ne TM'-2 ac:icent.

Ine list of researen needed is divided into 10 sucject areas.

1.

Imcroved Safety Research (Imoreved diagnostics Of accident, safety system interlocks, imcreved methods for qualifications testing) 2.

Studies of transient and small LOCA events 3.

Plant rescense to accident conditions 4

Fes: Accident Examina:icn 5.

Improved Instruments for accidents 6.

Fissien Product release and transport 7.

Primary Coolant and Centainment Chemistry during Accicen 8.

Hydrogen Behavior 9.

Plant Data Bank 10.

Risk Assessment 1372 310 f

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5/9/79 a

JL

.:, Dr. Ckrent corrrented tnat now might be the appropriate time to investigate potential improvements in containmen design, such as vented containments.

He suggested a vigo'rcus lock at containment designs ey research.

In respense to a question concerning the augmented research budget for FY SC, Mr. Levine noted tnat the current plan was to re-establish oriorities for the total NR*, resear:r effort Out not redire : this effort. He cid not foresee drom:ine any curran-easaar:n croje::s.

Dr. Siess gave scme suggestiens for recomendations to tne full Committee.

A grou: Of suggestions were intenced f r tne very snce:-tem, shcr:-ter and nea r te r.

These items ne :ncugn: were ne consisten aitn etner suggestions tne Sw::o :-ittee na: re ce i ve :.

fartner gr:u: of sug;estions indicate: i te s wnicn re:uired sh:rt-terr atten:icn or are narr w in ran;e. These ite s relate :: TMI-2 s;;e:ifically, er to etner 31, rea:::rs.

Three a:ner areas wni:n he ::csicere: treader in se ;e and of longer-:ec were matters relatin; to LJs in general, NR~ 5:aff procedures and :nilesc:ny in licensing, and A~R5 pro:edures and aniiose:ny.

Dr. Siess thougn: :ne Cor:.ittee sneul: we ri witn tne Sta" in :ne reactive mo e (providing acvice as nee:e:) for tne short-ter-im:11:a tion ma tters. Su: for ne icnger-term items he fel

ne Comittee sncule clay a mere active role, using Succomittees to devel: information in the customary manner.

Finally, Dr. Siess suggested some Sub: mmittee assign-ments to consicer tne implications of tne TMI-2 accident.

Dr. Lipinski reviewed nis list of suggestions for recommendations to tne full Comi ttee. The suggestions were divided inte crevention, mitigation, and re cove ry.

The suggestions included:

Preventien 1.

Status Indication / Interlocking of All Safety Systems 2.

Valve Positien Indicators 3.

Measurerent of Core Outlet Temperature 4

Measurement of Pressure vessel Level

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AT Meter (an indication of 6T between saturation tem erature corresponding to system pressure and the hottest core exit tnermcc0uple reasurement) 6.

Pesitive Ind. :atien that Natural Circulation has Taken Place 7.

Use of Control Systems to Mi*.igate Transients E.

Use of Coccuters to Perform Diagnostics t: aic 0:e rat:rs 9.

Cesign Basis fer Centainment !sclation 10.

Pcwer to Pressurizer Heaters 11.

C.C. Power Su: lies 12.

Revie..

1. Residual Heat Removal Syste :

' 3.

Ir.te;ri:y of Trimary Syster 3:un:ry 14 Single Failure Criterien (review its at:lica:ilit '

15.

Ancic.alous Transients (studies :e c:ndue:ed.-

15.

Environrentai Qualificaticr. Of Sa'ety Syster C:nte:'

Ci r:ui ts 17.

Interf ace Between a555 anc 5CP 15.

5:::e of.iRC Review 13.

Im;criance of Wormai Orocess E:ui:rer.: Du ri r. ;

Emer;encies 2C.

Systems Interactions 21, Operster Training Mi ti ca ti on 22.

Instrumentation to Fo11cw the Course of an Accident 23.

Reactor Shutdown on Secondary System Signals 24 Remote Ocerated Vents on Primary System 25.

Instrumentation to Cetect Boiling in Core Recove ry 26.

Measurement of Water Level in Containment 27.

Post Incident Recall of Operating Date (comouter storage of selected variables) 13])-

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8 Dr. Catton described suggestions he had for recomendatiens to the full Com.i t tee. He note.d. the proolem with the pressurizer loop seal. He also r.entioned tuc uncertainty associated with tne long-t:r. use of tne RHR sys tem. re stressed tna need to examine tne filter arrangerent in ne auxiliary cuildings. A cetter metnod to obtain :rimary system water systems under a::ident conditions merits attention. Dr. Catton suggested a stacy into tne :ene#its Of a E 03 cacacie of ocerati:r. at system operating p re s s u re. C ne' t0:ics Dr. Catt:n suggeste: c:ul: te ne sg je:: f:e stucies ne ra :

1.

5:ucies on Vaintenance 0.*.

5:acies er :: lin; a C re in a Cegraded 5:ste 2.

na:;rsi Circulatice (can it te inni:ite: :y cissclve: ;ases, new d:es tne elevati:n O'

r:enents at a s:ecific plant affe:: natural circulati:n, an a tem;erature boundry :ei:..

wnicn natural circulati:n is net usec)

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Sncul; an Engineer :e presen carin; a sni#ts 5.

Set te r C: rte:1 Rc r Human Engineerin; A;TER. 00.. SE55::..

Dr. Ox rent ce;a-tne afterncer sessi:n by geing :nr:ugn suggestiens he hac for orcering itecs into categories for review. Several categories focusse:

en areas wnere tne Cornittee might make early recomendations. Ano tne r categcry would be fcreed oy topics wnich must first be studied before tne ACRS could catemine whe:ner a reccmendatien need be made. A further category of topics includes items which must or should be reviewed by the ACRS as part of ongoing licensing activities.

Finally, some topics mignt be dealt witn in ACRS testimony. These to:ics were assigned to tne varicus headings J

in the THI-2 Implications Subconnittee senedule of April 30 anc May 1,1979.

Dr. Ckrent briefly discussed draft reccmendations for emergency procedures, coerating experience, contingency design measures, station blackout, water ham.er and the single failure criterien.

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5/9/79 9-v.r. Adaman'.iades fr - EMI gave a brief presentation on projects they have uncen.ay as a result of tne TMI-2 incident. A Nuclear Safety Analysis Center nas been forme: tc al:k as a clear iighouse of informati r; it will also produce re::r:s or wnat na::ened, why it ha:cened, and a re: Ort t: outline tne im:li-cations of e a :ident for etner reactors. The Center will rovide techni:ai assistan:e :: G a end Kate::clitan Edison during ne clean-a: an: recove ry c:eratiers.

Tne Cente* w'll produ e a cocument dealing witn c:ti:ns tne in-c s "y -i; : na#t t 00rsi er c ing as a nex* s*e: i"-Iwdic;:

e rat '" te! E-in;, cual'#i a* ions, C.A., an Diant Cons *ry icn.

s :s:- c:te: :na: tre 5:a" nas n:: yet finisned :T ars re uirin; C:-

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v.ne' a::r:s >' c res ney ir en: :: 10:6 at s;;* i*.e 1 a s. : -' ;a :. :-5 7 ;- e as.,re s.

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- 5:~e areas.

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Siess n::e: -e nee: :: :Or.#i r-tne :C:5 Oral comer.:s (Of ::rii IE, 1973; 1r. or ti ; : rin; :ne a, A C:.5 eeti n ;.

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ne :.:-i ties :: 1: ala::ca e Or :ne :: t e exten Of sa in; wnat sr;u ce ::ne, v. - it sncul: :s d:ne, and when it sneui: ce : ne.

Mr. Micnelson saic :na reactor vessel level indication is tne firs: item On nis list of priorities.

he felt this device would preclude the neec f r scce Of the special c:erational emergency procedures recuired by tne staff fellowing TM:-2. He noted tnat vessel level indication wculd provide useful infer.ation f r a nuceer of transients. Mr. Michelsen said that he favered het le; level inci:ation only; ne did not advocate a full range level indi-ca:icn for tne reac:ce vessel.

Tne Subcormii ttee tock u: the topic of "philosognical a:preacnes" to safety.

Sucn topics as the merit of tne single failure criterien should be re-examined. The use of three trains of safety equipment versus two could form a part of this study. Otner areas which may require examination include 1372 314

TM1-2 0**

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tne events wnich woul,c follcw tne 1055 of a vital syste-A c m;1ete station blackout witn tne it'st~ 0f all AC power forms anctner event wnien may recuire study.

Dr. Carten noted ne tncugnt it was im:crtant to : nsi:er cesigns wni:n would im: rove containments.

re wcult lice :: see tne effe:tive ess :# ine ::n-tainment against all ain:s :# ac:icents a::re:ially in:-=ase:, inclucin; accidents OeyOn: tne ces1;r asis.

C. Law :1' s.;;5;te:

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c# a tertic", i r:ve-e-:s : 19e a:-i e :- i :-:.ia; e ::e-et:-i.

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It was n :e: nat nct antil a::st one n0ur ci: tne station 0: erat:rs ask fcr assistance.

Dr. Okrent tncught it woul: De benefi ial if a quantitative casis could be set for taking various actions sucn as shutting dcwn plants. Nume ri:al guidelines for different acticn tnresholds would be an aid to regulators.

He noted further tnat an accectacle level of safety snould :e set for all tecnnologies.

Dr. Siess re-er.pnasizen nis viaw o' recommencati:ns to t9e full C:--i ttee ;

ha felt the Connittee sh0uld act in the rasctive mcde (keep informed of tne Sta"'s thinking and clan and advise them as needed) for the snort-term studies e

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and fixes. Tne majcrity o# ine Committee's attention should be devoted tc the longer range, nonspec:fic, more generialized implications. He mentioned the nee: :: confirm the oral recommendations formally to the Comrission and amplify ther as necessary.

Finally, Dr. Siess stated the need to de:ide what action to take on cending CE anc CL reviews and these

lints anien have been reviewed by ACRS but as yet have not receivec at c.:

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mate"ial provide: :: t e Sa:::m.-it.et f:0 E ;

't:3:te: 3re lists 0 for tnis meeting.

i.

NOTE: For additienal details, a complete traric.-ict of tne meeting is available in the NRC Public Docu.ent Room,1717 H Street, NW, Washington, DC 20555, or from Ace-Federal Reporters, Inc.,

444 North Capitol Street, NW, Washington, DC.

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SCHEDULE WREE MILE ISIAND LNIT 2 ACCIDENT IMPLICATIONS REGARDING NUCLEAR PCWER PIANT DESIGN APRIL 30 - MAY 1, 1979 (Tentative Extension Date: MAY 9, 1979)

~

1717 H ST., NW, WASHINGTON, DC - ROCM 1046 8:30 a.m.

I.

SPECIFICS OF THE 'IMI-2 ACCIDENT A.

Iatest information on the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the Accident i.e., latest chronology and interpretation of chronology B.

Report by NRC Staff on the conclusions from R. Tedesco's Task Force (concerning feedwater transients) and Licensee's response to NRC Bulletins 79-05,79-05A, 79-05B, 79-06,79-06A, ~79-06B, and 79-08 C.

NRC Staff comments on ACRS written and verbal recommendations D.

Comments by NRC Staff regarding Status of Natural Circulation Cooling (not limited to 'IMI-2), what analyses are available, procedures for natural circulation, documentation available on this topic from the different vendors and operators such as Davis-Besse E.

Discuss NRC recommendations regarding B&W plants F.

Other intnediate implications of MI-2 12:00 noon

• • • • • • • • • • • • • • • • • • LUNCH ********************

1:00 p.m.

II.

OPERATIM3 PIAN'IS A.

Dnergency Planning /Cperations 1.

proposal regarding added senior operator in control room of B&W reactors 2.

emergency procedures (onsite & offsite) 3.

NRC reaction capability and role

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. 4.

technical backup at operating utility 5.

techneial backup to operating utility 6.

role of onsite NRC inspectors 7.

clean-up procedures & equipnent 8.

others 2:00 p.m.

B.

Safety Design Questions From MI 1.

effects of process control system on plant safety during transients 2.

frequency of challenges to safety grade systems 3.

adequacy of water inventory in once-through steam generators 4.

shared facilities - degraded conditions 5.

enviromental qualifications of non-safety grade equignent 6.

enviremental qualifications of equipnent in non-safety building 7.

importance of normal process equipnent durirg emergencies 8.

Pressurizer connection to primary system, e.g., location, position 9.

Arrangement of primary system a.

" candy-cane" b.

vertical U-tubes

10. Design basis for post-accident heat removal systems

11. contalment isolation 1372 318

. 12.

vents on reactor pressure vessel and system high points

13. others C.

Instrumentation and Monitoring 1.

water level in reactor pressure vessel 2.

water level in containment 3.

indication of the status of valves and other components 4.

short-term computer assistance to operator S.

long-term developnent of computer assistance in evaluation of plant status 6.

flow meters in hot or cold leg of primary system 7.

others 3:00 p.m.

• • • • • • • • • • • • • • • • • • • • • • • BREAK **************************

D.

Mministration - Operator Action 1.

start-up check list 2.

operations check list 3.

adequacy of procedures for natural circulation cooling & other modes of operation 4.

improved operator training 5.

others E.

Mministration - NRC ktion 1.

how to pursue reactor operating experience a.

ANO-2 situation

~

b.

BG stress corrosion crackirg experience 1372 319

. 2.

appropriate depth of knowledge in NRC Staff a.

chemistry b.

system hardware c.

system behavior d.

others 3.

expeditious resolution of generic items 4.

others F.

Contingency Design Measures 1.

filtered vented contaiment 2.

remotely operated contalment flooding 3.

hot sampling capability 4.

instruments to sense and follow degraded conditions 5.

problems arising from H2 generation and behavior under abnormal conditions 6.

portable emergency equignent 7.

containment shielding 8.

others G.

Other Safety Issues Which Warrant Emphasis 1.

station blockout 2.

adequacy of de power supplies 3.

consideration of systems interacti n 4.

water hammer 5.

other generic items applicable to operating reactors 6.

provisions to preclude sabotage 7.

others 5:00 p.m.

AIUOURN 1372 320

. MAY 1, 1979 8:30 a.m. -

III. WHAT WOULD BE DONE DIFFERENTLY FOR PUWTS UNDER CONSTRUCTICN?

A.

Emergency Planning B.

Safety Design C.

Instrumentation and Monitoring D.

Administration - Operator Action E.

Administration - NRC Staff F.

Contingency Design Measures G.

Other Safety Issues hhich Warrant Emphasis H.

Effect on Neighboring Units I.

Improved Contingency Planning J.

Design Measures to Reduce Accident Probability K.

Applicability of Single Failure Criteria L.

Others 10:00 a.m.

• • • • • • • • • • • • • • • • • • • • • • • • BREAK **********************

IV.

WHAT WOULD BE DCNE DIFFERENTLY FCR PLANTS IN UIE DESIGN STAGE (PRE-CONS'IRUCTION)

A.

Philosophical Approaches to Safety 1.

broad approach to protect against future accidents 2.

siting policy (future policy) 3.

How does the 9tI-2 accident effect the estimate of risk - use of risk assess-ment vs. deterministic approach 4.

Do standard plants inhibit safety?

B.

Emergency Planning C.

Safety Design 1372 321

, D.

Instrumentation and Monitoring E.

Mministration - Operator Action F.

Mministration - NRC Staff G.

Contingency Design Measures H.

Other Safety Issues hhich Warrant Emphasis I.

Effect on Neighboring Units J.

Improved Contingency Planning K.

Siting Practices - examples:

1.

hydrological conditions assuming core melt 2.

population densities L.

Passive Safety Systems M.

Criteria for 3-Train vs. 2-Train Systems N.

Acceptability of Single Failure Criteria 0.

More Conservative Seismic Design for Selected Portions of Plant if the Likelihood of Exceedence of the DBE is Greater Than 10 1 Per Reactor Year P.

Others 12:00 noon LUNCH *********************

V.

IMPLICATIONS FOR FEDERAL SAFETY RESEARCH What research is needed to support the iMI recovery process?

Others a.

b.

1372 322

. VI.

HOW TO PROCEED & PRIORITIES A.

Recommendations to ACRS Regarding MI Recovery

' B.

Recommendations to ACRS Regarding Short-Term Action Applicable to B&W, W, CE, and GE C.

Recommendations to ACRS Regarding General Plan of Attack - hhat Should the ACRS Review?

hhat Should ACRS Subermittees Review?

D.

ACRS Procedures 1.

procedures for dealing with ACRS letter recommendations e.g., WI-2 letter 2.

procedures for the Conmittee's response to accidents a.

completion of MI review arx3 evaluation b.

other cases e.g., Browns Ferry fire, NR overpressurization incidents 3.

recommendations to the ACRS regarding the Cx.mittee's approach to CL review e.g.,

Sequoyah 4.

recommendations to the ACRS regardirg the Committee's approach to CP review e.g.,

Palo Verde 5.

other license reviews e.g., Millstone, Unit 2 stretch power VII. CIEER TCPICS 4:00 p.m.

ADJOURN 1372 323

e SCHEDULE 1HREE MILE ISIAND UNIT 2 ACCIDENT IMPLICATIONS REGARDING NUCLEAR POWER PLANT DESIGN May 9, 1979 1717 H St., N.W. WASHINGTON, D. C.

8:30 A. M.

I.

Meet with NRC Staff on:

A.

Current status of TMI-2 B.

Latest information on chronology (any new inform tion since May 1, 1979).

C.

Licensing approach to 0.L. applications.

1.

Rose with ACES letter but not 0.L.

2.

Those with ACRS letter pendirg (Sequoyah) 3.

Other 0.L.s D.

Licensing approach to CP applications such as Palo Verde.

II. Discuss Ptoposals of Subcommittee Members (Siess, 9:30 A.M.

Kerr and Okrent) re action plan for full ACRS.

BREAK 11:30 A.M.

11:45 P.M.

III.

Implication for Reactor Safety Research What research is needed to support the TMI recovery process?

Others a.

b.

12:15 P.M.

IV. Contingency Design Measures 1.

Filtered vented containment 2.

Remotely operated containment flooding 3.

Hot sampling capability 4.

Instruments to sense and follow degraded conditions.

5.

Problems arising frcm H generation and behavior unde:

2 abnormal conditions 6.

Portable energency equipnent 7.

Containment shieldirg 8.

Others 1372 324

1:00 -2:00 LU?CH 2:00 V.

Other safety issues which warrant emphasis for operating reactors A.

Station blackout B.

Adequacy of de power supplies C.

Consideration of systems interaction D.

Water hammer E.

Other generic items applicable to operating reactors F.

Provisions to preclude sabotage G.

Others 2:30 VI. Wat would be done differently for plants under construction?

A.

Emergency planning B.

Safety Design C.

Instrumentation and monitoring D.

Administration - Operator Action E.

Administration - NRC Staff F.

Contingency design measures G.

Other safety issues which warrant emphasis H.

Effect on neighboring units I.

Improved contingency planning J.

Design measures to reduce accident probability K.

Applicability of single failure criteria L.

Others 3:00 P.M.

VII. Proposals for Dispsition of Specific Iterrs.

4:55 P.M.

BREAK 5:00 P.M.

VIII. Discuss propsed plan of action for full ACRS.

6:00 P.M.

IX.

Develop Recommendations for Full Committee to Condider 7:00 P. M.

X.

ACCOURN

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b ACP.3 AD HOC SUBCOMMITTEE MEETING ON TMI-2 ACCIDENT IMPLICATIONS WASHINGTON, DC APRIL 30, MAY 1, & MAY 9,1979 ATTENDANCE LIST APRIL 30,1979 ACRS NRC STAFF D. Okrent, Chainnan D. Ross M. Carbon L. Crocker W. Kerr L. Tong C. Mark G. Edison M. Plesset S. Varga C. Siess W. Lyon W. Mathis J. Ray C. Michelson, ACRS Consultant McGRAW HILL / NUCLEONICS WEEK W. Lipinski, ACRS Consultant I. Catton, ACRS Consultant S. Wynkoop R. Wright, ACRS Staff R. Major, ACRS Staff D. Johnson, ACRS Fellow WESTINGHOUSE ELECTRIC CORP.

DEPARTMENT OF ENED.GY T. Turniman B. Washburn A. Rizzolo BABC0CK & WILCOX HEDL R. Borsum A. Schade EBASCO SERVICES D. Simpson T. Raney DUKE POWER CO.

S. Lewis JAPAN EMBASE A. Yaki CATALYTIC INC.

Y. Fujii-e W. Johnson WASHINGTON POST HARRISBURG FATRIOT J. Omay 13/2 j2b M. Spivak

_g.

TENNESEE VALLEY AUTHORITY SHAW, PITTMAN, POTTS & TROWBRIDGE T. Tyler A. Weisbard BECHTEL CORP.

PUBLIC SERVICE COMM. OF MD

~~

W. Smith R..Hollis MAY l,1979 ACRS NRC STAFF D. Okrent, Chairman E. Jordan M. Carbon R. Mattson W. Kerr S. Hanauer C. Mark H. Ornstein W. Mathis L. Tong M. Plesset R. Bursey J. Ray P. Shewnon C. Siess WESTINGHOUSE ELECTRIC CORP.

C. Michelson, ACRS Consultant W. Lipinski, ACRS Consultant T. Turniman I. Catton, ACRS Consultant A. Schade R. Major, ACRS Staff R. Wright, ACRS Staff BECHTEL CORP.

DUKE POWER CO.

W. Smi th S. Lewis DEPARTMENT OF ENERGY NATIONAL DEPT. OF ENERGY B. Washburn A. Rizzolo EBASCO SERVICES HARRISBURG PATRIOT T. Raney M. Spivak TENNESSEE VALLEY AUTHORITY T. Tyler 1372 327

. MAY 9,1979 ACRS HRC STAFF D. Vassallo D. Okrent, Chairman R. Mattson M. Carbon B. Grimes W. Kerr C. Thomas S. Lawroski W. Minners H. Etherington R. Boyd C. Siess R. DiSalvo W. Mathis M. Nixon D. Moeller C, Michelson, ACRS Consultant TENNESSEE VALLEY AUTHORITY I. Catton, ACRS Consultant W. Lipinski, ACRS Consultant D. Wilson R. Major, ACRS Staff J. Bynum P. Tam, ACRS Staff M. Burzynski W. LaRoche TOKYO ELECTRIC POWER BECHTEL CORP.

H. Hamada W. Smith STONE & WEBSTER PHILADELPHIA BULLETIN J. Coombe R. Taylor SHAW PITTMAN GENERAL ELECTRIC CORP'.

E. Solomon Noel Shirley BABC0CK & WILCOX~~

EPRI R. Borsum A. Adamantiades ACE-FEDERAL REPORTERS, INC.

DEPARTMENT OF ENERGY D. Hoffman J. Taylor B. Washburn NUS CORP.

A. Papadopoules 1372 328

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ITEMS PASSED OUT DURING THE APRIL 30-MAY l,1979 AD H0C SUBCOMMITTEE MEETING ON THE THREE MILE ISLAND UNIT 2 ACCIDENT 1.

I&E Bulleting Resoonses (a) SMUD, April 11,1979 letter, responds to I&E Bulletins 79-05 and 79-05A, responds to items 1, 2, 3, 4a, and 5 -- remaining responses will be sent by April 16, 1979.

(b) Omaha Public Power District, April 23, 1979, response to I&E Bulletin 79-06B - Fort Calhoun Station.

(c) Florida Power Corp., April 9,1979, response to Bulletin 79-05A, remaining items by April 16, 1979 -- regarding Crystal River 3.

2.

TMI-2 Emergency Procedure 2202-1.5 - Pressurizer System Failure 3.

Transcript of Commission's Friday, April 27, 1979 Mee ti ng.

Subject:

Con-tinuation of Factors Relating to Current Status of Operating Reactors.

4.

D. F. Ross: Viewgraphs (a) Schedules, Past Events (b) System / Component Operability Status (4/29/79) 5.

Draft Report (NRC - Staff Report - Evaluation of Long Term Post Accident Core Cooling of TMI-2). This is a draft SER.

1372 329

BACKGROUND INFORMATION PASSED OUT AS AN INFORMATION PACKAGE BEFORE THE APRIL 30-MAY 1, 1979 AD HOC SUBCOMMITTEE ON THE TMI-2 ACCIDENT. THESE DOCUMENTS ARE ON FILE IN THE ACRS OFFICE.

1.

Schedule for the Meeting 2.

ACRS letters and recommendations relating to the TMI-2 Accident (1) April 7,1979 (2) April 18,1979 (3) April 20,1979 3.

Chronology of Events A.

April 25,1979 Current Status of NRC Chronology of Events During TMI-2 Accident.

B.

GPU Service Corporation - Preliminary Sequence of Events Report (also includes emergency procedures for: reactor trip, loss of reactor coolant / reactor coolant system pressure, station block out.

C.

(A chronology is also given - Bulletin 79-05A see below) 4 NRR Status Report on Feedwater Transients in B&W Plants, April 25, 1979.

5.

IE Bulletins relating to T!!I-2 Accident: 79-05,79-05A, 79-05B, 79-06,79-06A, 79-06A (Rev.1),79-06B, and 79-08.

6.

Additional Comments by P. Shewmon 7.

Package of Recommendations by the Industry Advisory Group - Three Mile Island 2 8.

Criteria for Performance of Control Systems (Canada).

1372 0

THE FOLLOWING MATERIAL WAS PASSED OUT DURING THE MAY 9,1979 AD HOC SUBCOMMITTEE ON THREE MILE ISLAND, UNIT 2 ACCIDENT IMPLICATIONS. COPIES ARE AVAILABLE IN THE ACRS OFFICE.

1.

Report to _the TMI-2 Review Subcommittee, May 8, 1979 - I. Catton 2.

Memo from J. Ray to D. Okrent, May 8,1979 Re. TMI-2 Accident Review 3.

TMI-2 Accident Implications Subcommittee Work, !1ay 2,1979 - C. Michelson 4

General Comments on Scope of Work, May 2,1979 - C. Michelson 5.

Recomendations Resulting from Review of Three Mile Island Unit 2 Incident, May 9,1979 - Memo from 11. Lipinski to D. Okrent 6.

Handouts - R. Boyd - May 9,1979, " Staff Review of Pending OLs" 7.

Partial List of Suggested Subcommittee Assignments to Consider Implications of the TMI-2 Accident, May 9,1979 - C. Siess 8.

Implications of TMI-2: ACRS Approach and Procedures, May 7, 1979 - C. Siess 9.

ACRS Activities ia Relation to T'il-2 Accident, May 9,1979 - C. Siess

10. Supplement to memo of April 27,1979, " Preliminary Appraisal of the TMI-2 Accident, May 9,1979 - H. Etherington

11. Memo to ACRS from A. Bates, "

Subject:

Oconee Response to TMI-2 Accident,"

May 8, 1979

12. Should the ACRS recommend the following to NRC? Proposed for Subcommittee Discussion, May 9,1979 - M. Carbon

13. USA-NRC: Crder - Rancho Seco Nuclear Generating Station - Received May 8,1979

14. USA-NRC: Order - Oconee Nuclear Station, Units Nos.1, 2 and 3 - Received May 8, 1979 15-15a.

Information from S. Levine: Research Related to Recovery of TMI-2 (2 pages)

Single page of Budget Information

16. April 26,1979 Memo from R. Mattson to H. Denton, E. Case, D. Eisenhut, etc.,

Re: B&W Transient and Accident Analysis Methods

17. ACRS Activities in Light of TMI-2 Accident, May 9,1979 - W. Kerr

18. List of Recommendations, May 9,1979 - D. Okrent

19. Schedule of TMI-2 Subcomittee Meeting, April 30-May 1,1979 Showing Workload Division and Possible Action Sequence

20. Copy of ACRS Future Agenda, May 7,1979 - R. Boyd 21. Reactor Safety Research, FY 1980 Budget Amendment, Description Items, May 9,1979 (Draft) - T. Murley IS/z 531

..., 22. Improved Power Plant Availability Through Advanced Infonnation Handling Methodology - G. F. Popper and W. C. Lipinski, June 9,1978

23. Applicatkm of an On-line Digital Computer at EBR-II (ANL/EBR-082), R. W. Hyndman, M. R. Tuck, and K. D. Tucker, January 1975

24. NUREG-0557, Nuclear Regulatory Comission Staff Report:

" Evaluation of Long Term Post Accident Core Cooling of Three Mile Island Unit 2," April 1979 1372 332

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