ML20024C545

Forwards Addl ECCS Small Break Analyses for B&W 177 Fuel Assembly Lowered Loop Nss.Analyses Are in Accordance W/Small Break Model Approved in Rev 3 to BAW-10104A, B&W ECCS Evaluation Model, Except Two Mods Proposed in

ML20024C545
Person / Time
Site:	Crane
Issue date:	07/20/1978
From:	Taylor J BABCOCK & WILCOX CO.
To:	Varga S Office of Nuclear Reactor Regulation
Shared Package
ML20024C535	List: ML20024C534 ML20024C545
References
TASK-07, TASK-7, TASK-GB B&W-0419, B&W-419, NUDOCS 8307120788
Download: ML20024C545 (25)

Text

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Babcocic&Wilcox n m..m.i m r.,u,..

F u. Laie.12M. Lynchburg. Va. 24505

c.na.i:a Luut Junail

.luly 18, 19711 l

Mr. S. A. Varga, Chief 1

Light Water Reactors 11 ranch f 4 l

Division of Project Management i

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.

20555

Dear Mr. Varga:

~

for Attached is additional ECCS swall break ana g1 36W's 177 Fuel Assembly Lowered-Loop NSS. Thesa 5.onlyses are in accordanc'e with the small b reak model as appoved in

m'a p t for BAW-10104A, Rev. 3, "B4W's ECCS Evaluation Moan 1."

two of the proposed modifications in my letter to you oi

?!.s M, U73. These analyses differ froia t.has..in ioy 3cti.n to you of June 19, 1978, in that the proposed Zaloudeh Corre-lation modification was not utilited and two addicim.a1 brcala were analyzed. These analyses, therefore, aru intended to replace those of June 19, 1978.

A power level of 2772 Mlft is assumed in these analyses, fl Credit is assumed for operator action as deuccibud li, say lutt.

055, 07,. 01r5',

to you of -M 7-1,1925.

Break sizes of.04, d analyses, along 2 are examined. These attache

.10 and.15 ft with the breck analyses in Da @D3 Wren -3 3 "PfTS Analysis of BriW's 177-FA Lowered-Loop FSS," constitute a couplete ti, bn t' holly spectrum of small break analyses which we bell ua in conformance with 10 CFR 50.46 and ID CFR 50, Appaudix r.

l Your expeditious review of this submittal it ec.tuc a t e d.

If you have any questions, please contact me or fienry Bailey l

(

(Ext. 2673) of my staff.

I Very-ruly you:j,.,

j f

1, f y..

f*/ -'

.f aues 11. Taylor Manar < r, Licenmm t

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JHT:dsf l

Attachment I

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bec:

J. P. Jones (t</o)

W. A. Cobb (w/o)

B. A. Karrasch J. C. Doddcas (w/o)

J. J. Stewart (w/o)

'G. N. Olds A. H. Lazar E. G. Ward L. J. Stanek (w/o)

J. T. Janis (4)

J. D. Phinziey

5. !!. Duerson J. J. Cudlin C. D. Russo11 (2)

R. C. Luken (2) ~

G. T. Fairbum (2)-

F. J. Levandotki E. R. Kan's J. D. Agar J. R. Concklin (w/c)

B. M. Dunn R. C. Jones L. R. Cartin J. H. Taylor (w/o)

H. A. Bailey Q. E. PaYks D. H. Roy L. R. Plotka (2)

H.'S. Muir R.

L,. Reed (2) i

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. ~., J t ec i t br uka at th: pump dischstge has becu performed

'the smil brenk evaluation model described uu tpla.i s e p t-te a.im.

nru' s yy v4 b.

.1 b >. n.

mM Fvalnation i ndel

• alour, with two of the pro-e., it.,o _ r e p # g, g -.. t N n tr.:

t!aa ruportsif Huy Zi. 1976 (.3.11. Taylor co S.A.

ponn.I melif.lcartmn @::cribed Jat action is wed to achieve suf f1-chin study. Operato.

VarEn) uns utilizud los cient and balauend Unn thruvah all four hig i pressure injection (UPI) lines.

(J.H.

Tha operntor nutloo is dancribad in dotail ii the report of Hay 1,1978 naa,.J.

Taylor to n.L.

The analysis contained huraiu, coupled with :he analyses of BAW-10103A.

"F.CCS Analysis of Bl.*E'n 177-TA Loworod Loop DSS." provide an appropriate sp The results of crea of brinks for tha avaluation of a sen12 leak transient.

2 tha pinuta can be ops rated up to a power level of 277 i.ha analyen shnu tb 9-Hut uithin tha critaria of 10 CFR 50.46 and Appendix K of 10 CFR 50, J. liethod of Am trqia, h

5 Tha nualysis machod uced for this ovaluation is that described in C apter "llt.U's ECCS Evaluation Hodel," along with two of the modi-of DAW 10106, as 3 1978 (J.H. Taylor to S.A. Varga).

3 lications deucthi la the raport of May 26 Iha two modificatione utilised were the two mode inner vess l volumes tha phasa distriburinnel multipliers for buuble rio in til contro The CRATf2 code is used to develop the history of

[

uithin the reactor vnsmal.

che CRAN *imodel uses 20 nodes to systou hydrodyuemics.

the reactor coulant simulnto the reactor cuoinut nyatow, 2 nodei for the secondary ' system, and A schematic diagrama of the model is shoun in noda for tho'rsacter building.

Control volumes (nodes) in and Figura 1 alo,ub u.i th i.hs nods dascriptions., - ::11 cumtected by a

sound th *raml hsc ha snolysed in this report are assumed to be located at l

Oucrant flov. s t.:

93 piping hotunen t he reactor coolant pucip discharge th. hnttu d - ::.

. h1

'the Ullson, Granda; and Pattersou average bubblu rise t

l r.no the m ehu w pl.

Within the rcastor vassal, howaver, multiplicro eodal la unnd for all nodas.

of 2.38 and 2.0 sra applied to the calenlat.ad bubble rise velocity in the c The justification for the noda and the remaining vassai modes, respe;tively.

10104 use of 2.33 wultip.tiac value in cura node J.s given in Appendix y of BAW fa The report of Hay R 1910 (J.D. 'faylor to S.A. Varga) justifies the use o

-nd the upper plenum regions.

iu!tipilci ci 2.0 i.a iba J suacomr, louer alanum, i I

r M

er

r' + + ;,. r

.*'de for condit ions and syncem responses durius rr.:

.ns#r.., int, n ilu-arc %it :

'ths r, recor in.uine"L.ity at 102% of the a teedy-state powe'r level of 2772 1Mt.

d..outsinmninly, and a d'achargo coef'ficient of 1 0 is h

rhn If nle iren. <= bi liernoulli'n equation was used for the sub-m t d for the v..tJ n-nualysis.

cooled portion of thn transient, while H oody's correlation was used in thn two-phasu puti.luu.

c.

Llo of f sica pourn, fu availabla.

d.

The rent: tor trips mi lou pressure at 190 ) psia.

The carnty cods laugin autoring the core ifter a 0.5 second delay from the a,

tima the ynneter trip air,nal in reached.

The Itc puwes trip and coast down coincid int with reactor trip.

f.

una coinplata train of the amargency safc3uards system fails to operate, D,

lanvius tuu CWc.nd only one HPI and ot a LPI sy tem available for pumped fujaetion to wLeignta the consequences cI a cold leg areak.

'4hs au::lliury Is idwater (FU) system is z saused to be available during the h.

Ita tein function is to terc ye beat from the upper half of the transisnt.

/[

When the sec-vinvine, tha initial stagrs of the transient.

atnam genernem enda$ y cide of t ha nr:ims ganavator becot es a source of heat to the primary cysten, the assunction of auxiliary yU tiaximizes the energy that must be

relieved,

i. ESTAS signal error band is considered it: the analysis to signal the actua-tion of tha UpT syctmit.

h Tha penh liunt hant ganaration rate in the hot pin is the maximuci allowed hv thn ench i nni en:>cifications at the :10.5 ft lovel.

i aparatnr nedou in cakan to increase thrHP1 flous to the intact cold logs h.

t 10 uluutso follouing ths ECCg inattacies signal. This action is ex-piniuad taora fully in the Hay 1,1978 report (i.B. Taylor to R.L. Baer)

Sinec tha citAPI enleulatinus shound partial core encovery for some of the breal:?, speci f f r,Ils tbn 0.05.%, 0.07, and ti.085-fts br. *:s. a TOMI analysis uns perforned to daitumine th inner vessel nr.ixture heirbt. The FOMI

-->v

\\

.;~

.ois t-a us oceau pi aducth u irliidu the 'vassati, i.e,-

...;..,.....,,..-...,s..i h.u.e h..: c, Elanhtna, n.91 isr6ory metal hhat. TocN-

~

tl..

i.n p,..ite r. +.no g..n! t i u. w: L td.il..e \\ *.

i hu.ticLcf.bution 1 i. Lh3 ULamrPouccOS uns chuDen tu tha en epia is y nt tha Juput enicoli cinun.nuJ,-na descritad 'in the sub-M ol nt; 1.ianunitarprodccionoftoysuojiIo' val. By sp-

.. s i n

..n.,o p;i.. p wii.

.ia uci taight,.the e ore othasiing rata vilrals' be un-d.4. a 8..mI.inq v b. -

iran 1rinh in nu overe cf(ktion of the steau superheating d n, p e r i tan t ed; thereby 1nd the peak cladribys tmapeenturo. j Jn Figure 2 was prd su t3N h AM calcalacio. and

~

the rt::i n) puue,.:b: p. dunni s

. s, s

'cix-unr inpinuv.nrnd niih r.:rdin1. peaking facto of T.O.

Thsn, the 1csultar.

N turn height is reprasnuentive of the averago channel rendi.tions and is 'cM-s w

w s

servative relative to that for the hot chast:el. To.utiliza EM l'over shape in Q

)UMI, the shapa uan divided inn.o 26 axial ti. des. '"

s

.g

~

Sennm production rina to prinaary metal heatlag and Gaihiis within the inner As J

.v -'\\

vassal was aestuned to have a distribution aWar to that for deu, y heat.

b such, the complexity in the input generatic s for10AM vas reduced to finding

• x so "equivalcut. doeny pount" which would gen erata the Mae amount of steam s.*

.-N 4x that which is proituced Irdu all sourcsa. ' U is of this steam ypduction' shape p-s s

z.

m s

iuulta la enuannativa cara bixtare hsicht s for the following rests &st s

M 7

V N

y 11han tha cura is ue.avared, scane of the pestas produccica f.ue -to primary.

s

,N s

s, matal haating and finshlug would not bs used in esiculati?g the miFhrt% w' yy t e

Invol. Thus, ib:., mixture height would 'as underestimated.),

~

/

A.

lly using thL shop., the ouid fraction at the core,,!.nlet is sf N.*

In act h.

i.nality,,dus Lu ::tusus p1.uduction in thi Iowar plenu.o anak statamquen bubble risa int.u tha coca, a void fract ton %M11 exist at the core inlet.,,,

,s thin initia3 cora void fra etim tesults in additional bubbles v

w*

Turthermera:

rising thront;hout ths core sifsture and isssradras the entire cas voidj a 'y w

<.ha assuuma shapA tmdtkott1(atns the core void Jyaction, ficcYinn." Sie i.ha reintira b.d nht in uudarssticate'd[

D

,s 1

e Sines the s::131 pouar distribution is' $oirs tetrardgthq top of the core I

f

2) the e.njority c f the s:si.m prodnesion 1:112 be calculated to (asa Figent T

i.

occur tousrds tha outlet of the core. Astlist,1@/,thagtotsisteau, production due tu primary escal heat sud flahirs,%nid be haved towards j

thn bottne ni the e.om.

'fhn distributrun an lytrynill yupstini:ico the t

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s N

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h regb>pa of t! 1 corn oust, 81htilarly to.:ho dis-gu t,i f. neo t e.o :.. h 4%.

.im o n o 8 0 carm tt 'in a couansvative mixture height.

e.ac ie n Li.dm rinq.ictoried using the VIETA code in tha mannar do-

!iamdg0 fm bn : N T h:1 ew ' imipe.

ha ful.eular, mhlic tua.it nusumptions aru ilmit %

.:.r g o..

.. I i L.a.o. k J + ! r w.o ii.n i un :

ylvtw ! uns used wi h a radial power factor of 1.67.

(

e s 3 hn y m.,

ump.. J s

a.

Win mazigiaco ncenia uuperheating and s ts the peak local poucr at 10.5 i s

~ s

-T E

. I. nrt ic e nclinkil ntweifiention LOCA 31ait.

a l

.s 4

Coolan2"f4m and enlatura loval were tak a dirac ly f.om the FOAM calcula-

- b.

Asdidussedabove,themethodsutilizedinthePOAHcalculations s

tiosos.

'\\icetnt 'in con.yrvative values for these parameters.

y N..,

End of liIc viu possures were used to :ouservatively predict the inci-s

't.,

s  ;,

dancysof.fudi pi" wpture.

v

' i u

M r

I

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3 'llres(Mtrots :QiResults Topical Ecport NAh 10103A *Rev 3, presents che analysis of a CIT line break,

_Q braak th. cha RC puay discharge and the spectrum of breaks at the s

V :ba O 3 ft2 i

g

,1 Ac pulp suctiod. AuYubcua in that report, the results of those analyses are

/

vholl'y in coup 11aucYbith the criteria of 3 0 CFR 50.46 and Appendix K of 10 Those analysss are still valid sat conservative in light of th's in-s

' ~

l t,

,.. ja 50.

1. f 4 pect of,the mudaJ modifications. The repoit of Hay 26, 1978 (J.H. Taylor to

,d S. A. Vargo), N.uibac the impact of the at difications.

\\s la thc pranuumnlysis, braaks of 0.04, 0.055, 0.07, 0.085, 0.10, and 0.15 c, A

$5 at ths RC puap dinharga are evaluated. Figur 3 shows the RC pressure y

182 l

A_s shown, each accident init'ates CFT flow within Yespense for each brsak.

2 break.

POO secentla :er apt 84h U.04 f t t

4 zho.m frMrr) wixt,ure haight as a function cf time for each break of

, ? %:,,,

Mm :

\\ q tper n uw.

• u. sy byrina from tho'lir.ere$ minor core uncovery was ca 2.brasks. For tha 0.04, 0.1, and l

13eedjor the th(th,r1.07, and 0.085-f t 2.brsen as@ cogs udIovary was calcu'.ated and, thus, no temparature ex-l 0.13 _f t e

cUrsioDU Uc 'My [

brack cehiayss a as uh op of affective ECCE (the HPI injected

\\

s J'isID404f tf

. s 1

~ '

\\[^ itgha Pitert.o$'12pl with tl>a core d nay heat and the uCs met After 3000sucen[s, '1hs'rh a 'h' ara ' mixture beit:it of 13.5 feet at this tiai.

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mi atiw jevais will. cop siuvecs chas, fur all smaller T n. i,1 e.ned tira r o, nn.mul inid the itPI nirnia r.sm pittigate the tran-i n....i t r. 6 n.,

.ui i.

..e

. n ot.

mall br'.sk soectrum (0.04, 0.07,

in : ariorning the n.wif tnia, thu historical As slun n by Figure 4, only U.J, :md 0. idii' b..nka) win parfuneed fi st.To further assure that the the 0.0/ it ' in uih e :o:ot tad in coro smcover t.

2 breaks were analyzed.

bs.1 fi:" o nt.r,ine I, tha 0.055-an l the 0.005-f t 2

s.,,.: e e we.

'these ca' son tnsuJ rnd tu nenne cura uncovery inut less than that for the 0.07-f t All then. cens were analysed for t.saperature response by utilizing hrenh.

The peak TIIETA cpdel Finnrn 5 shows the cladding temperature responses.

thrt 2 break, was only claddinr, teeparatura for the worst case brs.ake the 0.07-ft Thus, the analy-1092F i.hich is weil bolow the 2200P criteri 2 of 10 CFR 50.46.

cia demousstutes chac alLu'a 17NA louered loop plants can ba operated

.Lavels up cu 2772 IMc nnd satisfy the BCC8 seceptasse criteria.

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P.o. Sea 12so.LynsNewrg.va. 24505 Tensmann missa.stit July 18, 1973 Mr. 5. A. Varga. Chief Light Water Reactors Branch #4 Division of Project Management Office of Nuclear Reactor Regulation

~

U.S. Nuclear Regulato.y Cozaission Nashington, D.C.

20555

Dear Mr. Yarga:

Attached is additional ICCS small break analyses for 34W's 177 Fuel Assembly Lowered-Loop N35. These analyses are in accordance with the small break model as approved in 3AW-10104A, Rev. 5, "B&W's ICCS Evaluation Model," except for two of the proposed modifications in my letter to you of

, n 'o.

These analyses differ from those in my letter to you of June 19, 1978, in that the proposed Zaloudek Corre-i 1stion modification was not utilized and two additional breaks were snalyzed. These analyses, therefore, are intended to replace those of June 19, 1978, A power level of 2772 )Rft is assumed in these analyses.

i Credit is assumed for operator action as described in my letter to you of :, *,

1"**.

Break cizes of.04,.055,.07,.08T, f are examined. These attached analyses, along

.10 and.15 ft with the break analyses in...

.w m a, "ECC5 Analysis l

of 34W's 177-FA Lowered-Loop N35," constitute a complete spectrum of small break analyses which we believe to be wholly t

in confotsance with 10 CFR 50.46 and 10 CFR 50, Appendix K.

Your expeditious review of this submittal is requested.

If you have any questions, please contact me or Henry Bailey (Ext. 2673) of ny stsif.

Very" ruly your,s Vf y.>. ': ' W. og, u. -

t a

James H. Taylor Mana{ct, Licensist JHT:dsf I

Attachnent cc:

R. 3. 3otsus (38W) l s

Th, Basteth I.Wh8tes Cemessee # Estachemse !S$7

.t bec:

J. P. Jones (w/o)

W. A. Cobb (w/o)

3. A. Earrasch J. C. Doddens (w/o)

J. J. Stewart (w/c)

'G. M. Olds A. H. Lazar I. G. Ward.

L. J. Stanek (w/o)

J. T. Janis (4)-

.7.

D. Phinney S. H. Duerson J. J. Cudlin C. D. Russell (2)

R. C. Luken (2) "

G. T. Fairburn (2)

7. J. Levandotki I.R.Ede J. D. Agar J. R. Concklin (w/c)

3. M. Duna R. C. Jones L. R. Cartin J. H. Taylor (w/o)

H. A. Bailey C. I. PaYks D. H. Roy L. R. Plethe (2)

H. S. Muir R. L. Reed (2) e O

4 e

OS 8

9..

O

.9 e

k I

1.

Introduction Analysis of a spectrum of small breaks at the pump discharge has beca performed The small break evaluatios andel described for Ba's 177-FA lowered loop plaats.

is 3AN-10104, 3ev 3, "3W's ICC3 Evaluation Model," along with two of the pro-l 25, 1978 (J.E. Taylor to S.A.

pened modifications described in the report of May Verge) was utilised for this study. Operator astica is need to achieve suffi-

,, cient and balanced flow through all four high pressure injection (EFI) 11 ass.

The operator action is described in detail in the report of May 1,1578 (J.E.

Taylor to 1.L. Iser).

The analysis aestained herois, coupled with the analyses of 3AW-10103A, Rev.3, "ECCS Analysis of 3&*i's 177-yA !avered Imop NSS.'" provide sa appropriate spee-The results of trum of bre'aks for the evaluation of a small leak stansient.

the analyses show that the plaats can be operated up to a pesar level of 2772 Mit withis the criteria of 10 CFR 30.44 and Appendia E of 10 Cy130.

2.

Method of Analveis The analysis method used,for this evaluation is that described in Chapter 3 of SAU-10104, lev 3. "3W's ECCS Evaluation Medal," alang with two of the modi-fisations described in the report of May 26, 1978 (J.E. Taylor to S.A. Yarga).

The two modifications stilized were the tuo mode immer vessel staulation an f

the phase distributional sultipliers for bubble rise is all control volumes The CIAyT2 eede is used to develop the history of within the reactor vessel.

the reactor coolant systen IfuMi--'as. The CIAyT andel uses 20 nodes to staulate the reactor coolant system, 2 modes for the secsadery 'systes, and one made for the'r'eactor buildias. A mab=atic diagram of the andel is shova is Control volumes (modes) in and yigure 1 along with the nede descriptions.

around the vessel are all connected by a pair of flow paths to permit counter-d to be located at

... The breaks analysed in this report are assume serrent.. flow.

~

th6 bottom of the cold les pipias between the reactor seelaat pump discharge The Wilsea, Grunds, and patterses average Imbbia rise and the reacter vessel.

Withis the resstor vessel, however, amitip1(ars model is used for all modes.

of 2.34 and 2.0 are applied to the calsalated bubble rise velocity is the core mode and the raesining vessel medes, respectively. The justificaciae for the use of 2.38 nultiplier value in aere made is given in Appendia y of 3AW-10104.

26, 1978 (J.E. Taylor to S.A. Yarla) justifies the use of a The report of May amitiplier of 2.0 in the douncouer, lower plenus, and the upper plenum resions. e l

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The following assumptions are ande for conditions and system responses during the accidents, The roaster is operating at 102% of the steady-state power laval of 2772 s.

Wt.

b.

The laak occurs lastantanosasly, and a discharge coefficient of 1.0 is used for the entire analysis. Seraes111's equation was seed for the sub-cooled portion of the transiest, while Hoody's correlation was used in the two-phase portion.

e.

No offsite power is available.

d.

The reactor trips on low pressure at 1900 psia.

The safety rods begia entering the core after a 0.5 sessed delay from the e.

time the reactor trip signal is raashad.

f.

The RC pumps trip and coast down coincident with reactor trip.

One asuplete train of the emergency safeguards system fails to operata, 3

leavingtwoCFTsandonlyseeIF1andoneLPIsystesavailableforpumped injecties to mitigste the, sensequeuses of a sold les break.

The s==414ary feedveter (FW) system is assumed ta be available isring the b

Its asia fumatica is to remove best free the upper half of the transient.

When the see-steam generator during the faitial stages of the transiast.

endary side of the steam generator becomes a sourse of heat to the priasty systes, the assumption of M14ary yW anzinises the energy that anst be relieved.,

error band is considered in the asalysis to signal the actua-

. 1.

ESyAS si l

ties of the EFI system.

l The peak linear beat generaties rata is the bot pia is the assians allowed J.

by Sie ' technical specificat' ions at the 1053 ft level.

rator acties is takaa to sacrease the EFI flows to the intact cold legs L

at 10 mientes following the ICCS initiatism signal. This action is en-plaimed more fully in the May 1,1978, report (J.R. Taylor as 1.L. Baer)

Since the CIAFT calculatione showed partial core uncovery for some of the t br. *:s. a TcAM analysis treaks, specifically the 0.055, 0.07, and 0.085-ft The 70AM was perfora'ed to deternise the inner vessel sincere bed;4t.

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,<w.

l calculation included all sources of steam production within the vessel, i.e.,

stesa production due to decay hast, flashing, and primary metal heat. To es-pedita the 70AM analysis, the distributica of the steam sources was chosen to

=4=4ed*a the complexity of the input calculations and, as described da the sub-eequent paragraphs, results in sa underprediction of the swell level. 37 un-derestis. sting the core sixture height, the core steaming rate will also be m-detestinsted; thereby resulting in as overestiastion of the steam superheattag and the peak cladding temperetare.

The saial power shape shown La Figste 2 ms used in the 30AN calculation and was isolensated with a radial peaking factor of 1.0.

Thus, the resultant mix-ture height is representative of the average channel conditicas and is son-servative r, elative to that for the het channel. To utilise the power shape in 30AM, the shape was divided into 26 asial modes.

Steam production due to primary antal heating and flashing within the inner vessel was asemed to have a distributism similar to that for decay heat. As sech, the complexity in the input generation for 30AM was reduced to finding as " equivalent decay power" which would gaaerata the some amount of steam as that which is produced from all eeurces. t!se of this steam production shape resalts in conservative sore mixture heights for the following reasons:

When the core is uncovered, seen of the steam productisa due to primary a.

metal heating and flashing would set be used La calculating the sizture Thus, the mizture height would'be underestiasted.'

I level.

In ac-h.

By using this shape, the void fraction at the core inlet is sero.

tuality.,due to steam production la the lower plenus and the subsequent bubble rise into t's core, a void fraction will exist at the core inlet.

Furthermore, this initial core void fraction results in additional bubbles rising throughout the core mixture and increases the entire rote void frac ~rion** Since the assumed shape underaatiastas the core void fraction, 1

the mixtu're height is underestiansed.

Since the axial power distributism is skewed towards the top of the core, c.

(see Figure 1) the anjority of the steam production will be calculated to escur towards the outlet of the core. Raalistically, the total steam production due to primary metal heat and flashing would be skaved towards the bottaa of the core. The distribution analysed will underestimate the 3-4 1

i i

l void fracties la the lever regions of the core and, similarly to the dis-aussies in ites b above, will result is a cesservative airture height.

The best-up calculatime was perfereed using the TIETA sede in the meaner de-scribed sa section 5 of BA9-10104 The following additional assumptions are stilised in the TIEIA evaluations The power shape of 71gure 2 was used with a radial pesar faster of 1.67.

a.

This amaisiscs steam superheatias and sets the peak iceal power at 10.3 ft at the t=*h=4e=1 specificatima loCA limit.

b.

Coolmat flow and aiature level were taken directly from the FOAM calcula-tions. As discussed above, the anthods stilised in the FOAH calculations result in cesservative values for these patsasters.

End of life pia pressures were need to senservatively predict the inci-s.

dance of fuel pia ruptare.

3.

Break Spectrum and Results Topical report IAH-10103A,1sv 3, presents the analysis of a CFT line break, the 0.5 ft2 break at the RC ymp discharge and the spectre of breaks at the EC pump sostiosi. As shown in that report, the results of these analyses are wholly in sempliance with the eriteria of 10 CFR 30.44 and Appendia 1 of 10 CFR 30. These analyses are still valid and conservative is light of the in-pact of the model modificatisas. The report of May 26,1973 (J.E. Taylor to S.A. Targs), describes the impact of the modifications.

In the present analysis, breaks of 0.04, 0.053, 0.07, 0.083, 0.10, and 0.15 its at the EC pump discharge are evaluated. Figure 3 shove the RC pressure roepease for each break. As shows, each accident tattiates CFT fisw within 2 break.

2200 seconds easept the 0.04 ft Figurs 4 shows (CIAFT) usatore,beight as a fuastion of tian for each break of A

As saa be seen from the figure, ainor core uncovery was calsv-the spectr a.

latedf'sItst$ 0.053, 0.07, and 0.085-ft8 breaks. For the 0.04, 0.1, and 0.13-fts breaks as sore usesvery was calculated and, thes, as temperature ex-earsists escur.

The 0.04 fg2 break achieves a antah up of effective ICCS (the IFI injected into the intact as1d less) with the core decay heat and the 1CS metal heat at 3000 seconds. The core has a mixture height of 13.3 feet at this time. After

4

r 4

For 3000 seconds the sixture level will rise in the core due to ascess EyI.

breaks smaller than 0.04 ft the secah up will occur at approzinately the I

same time and the sore misture levels will drop slower; thus, for all smalist breaks the core will remain covered sad the EFI a'one saa mitigate the tran-siest.

In performing the analysis, the historical small break spectrum (0.04, 0.07.

2 breaks) was performed first. As shown by yigure 4. only 0.1, and 0,15-ft the 0.07-ft2 break resulted in core uncovery. To further assure that the 2 breaks were analysed.

worst case had been obtained, the 0.035-and the 0.085-ft 2

These cases resulted in some core uncovery but less then that for the 0.07-ft break. All three cases were analysed for temperature reopease by utilizing The peak ths TEETA cpdes Figure 3 shows the cladding temperature responses.

2 break, was caly sladding temperature for the worst case break, the 0.07-ft 1092F which is well below the 22007 criteria of 10 CTE 30.46. Thus, the analy-sia demonstrates that BW's 177-FA lowered loop plaats esa be operated at power

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