Text

Draft Rept, Decay Heat Removal Problem Associated W/Recovery from Very Small Break LOCA for C-E Sys 80 Pwr
	ML19254E918
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	05/31/1979
From:	Michelson C; TENNESSEE VALLEY AUTHORITY
To:	;
Shared Package
ML19254E915	List: ML19254E914; ML19254E918; ML19254E923;
References
	NUDOCS 7911050061
	Download: ML19254E918 (50)
	v • d • e

{{#Wiki_filter:.- ....,-....a....... .........c. .~ ENCL esu2W... A / .. ~,.. Am ,. _ W 2 7_ ea's e=,gere .De cas Meaf 2-n / AsA/w A. c w s 4/ M M y % ~ .5 // Be f AscA A&-n Fm o. V ~ V fu CE %,_ A m 20 P/#/2 ( ~ /44, / %fn,- A alsa Se c %- /~- / A1.c o N77 r A f-sJ269 '77 gotjfgg7gggj

2 .. ~,.. L-nt/- o/ C m & r2 ~ 1 z ndacAw 2. /% stea / Artaxesref as#' i Asraskna/es V .e Rdis6/ At-/scA A & A s-of Bear Af B~/ c/ 4 Ars //s//e Gusx fafire fesu//s <C Arta si [ne&drr: /S. Addifitsa/ 6xsirlem/rsus [.a As<sndie A Od,ks As.sse ts /sd w,& Asf-lotA As Ar ci &n A4 / Pms va/ /s-v Yms.%s# Brn k' LocA v Aussd/x 6 3r>w// R<nf L osA A+<4sn As. n y y re Lska &g;xen/qs s 1269 '78

s . 1,} f,,,.,{,; a '.:.. cal 'a. h.h.% a ..... W.. -:.' :,,m '~. : ' - e 3 .. ~... c. t 1. zsAJm AdsA- /x-An .Xhu.6 Ado .sm n s g r u sd/ (s' J-ar&h &f.u.- y 27-27 )?f if7s' er aba of +r~f cen-A.1 v~rA M, J s i o On b A O C /l N /b. p W.4/.'At.le*. -8/ JWA Q. D r 12/d d /2rst I s-6 esn os d & A m a>-'A n d v or 1/ cru f.J-d.) a w / Wu-md,fAJ . -i C E SSA /2 00 y D Agyd - ~ dem /.a A f As A X y pmo afb pp.

6 es n m-n -aa.

an-A 4 &M3 L 1. a n *. - JA G G V J/s T/] -CE--/ 4 / l.A/-%% /2 s '7J~) a w /g f D' +

.AJd a,

qpn'y B i La a -AL-A a~ yJazt*. rya a> > m-rrA o -o / p a L-A a dey-f M e.e r - - 23 _AW xA as& duvh at-McA /s,-r ua g s&X .aea n k. -s&d rd,L and v r. it ~2d'. rdyA AA es x4 + 2 et j M ep-A 7 1269 '79 \\

\\ a ~ \\\\ \\\\ ~~ ~ \\J p.- c A.un/ kemnas a& - c3-%dys ~ u v -1,d,_ J a-- - J s,1 A x w s ~_~.-- nu fn as p ~~ 3~,a' nn 4-a f G f 4-, i. J4,& 4 4 .,[ - . a. a ;2-eurai% m2 Af

a. /s;A.//t Ax__

a v y R"~ - cra.u-m ( o a4) J 2,., </&/ A., ~ ~ ~ ~ Wr*c ~~ Q A 1 2 / so ~ A) n. A < s a 4 c. A A-gg_ /-M h ad c-> & ' 1. 24 p-a ajs L... ~~ 3 -y f 44 4t j fp p o-- &~ Ads-g , ~, ,&,, /. n ed L 2 mp- ~ ~ ~ ~ z<.e.- -L d Ak h$.;"A b4 A& WWfY l5! f,xf

Y

~j~4-J /~ y' "q- ~~~ A,das sA~Lu e -z-w p d n, p pesAJ zWo /.~a-en.- ccedeef eq-7x-. , b~ ~ m _G.. %K L. e4 m2 aA-ur' ~ - a, -x- ~~,-s-- c4-J J% M-f mf w ~

y

~,t,. - 6 n. 1269 '80

....,.>..m._. . g,,,; ,, g.,. c ... ~,..: c. w 3. Ldu/J &6 LeM Ahde: si_2n Jhdhaw/ u WYY //Y , $"YYY ld"~ &r/h. s ~# s .n1 e -a - A~ A - sM s>r-Lod A cd a y s d2 3-A d & w d4 N --- /Ag s_4 A. K &L2-a e.s & s e - .c-e a 9'. # w A f / S 6. / W -) g/n Ad A ./- M yA-q- .-A jfR f.4 r s-r a s 7 ~ sm a d m' M

ri%

ao -m A & J.sa, A s s u ms S -e-.o

t? AM,a. A pA: -//wk&'<

e a &@= m,aV' 3 n a.ds' A C E ->- m 7. 4 J J ' f / A-- A d //. A as-s m. JAd% /-t w d

2 m bs (/g/~A pm a.s _syA

/mMa' ) a s u. - - ~,.- i <w g ny m3 WJ dg' x a.< dm ( cw

w.s a.n r e.e w a

,,.-J a ad as gx>csC&- a7 4 A coMea_t:>vsyabj L A,n Axer # m.A-4yd y & -- f g & A A / f s _. ??Xck. /- 7 1269 '81

4 4 a s,.. '.., k..' ;* g r ;,,,. - ^'r ,s.. ';. ;,,

~'

s '^ --*#'*-"~"2-#* ~' ' 'n.. aa.*g i og s 'p i, 6___., . n, ..mn. ..n e.m. ..n _l h ( Y l f G f AWs Ce lc.s/Y.Ce./- b s. D UxA & /d v a p y a a w.J'- LosA /1wd. 24a c<.4 dse au v Ya A 0 J% eds-e-A f DfA /-2 yp a .s#sph,%./ a/Af-f & -n-qd #- m e-- x a ns n n sx +/ (/ Ad$2 MM' , nd ~ mmM.t41 s r/ i/ // 141 A - p A N A .dss.a 4.e r eg 6 u~6ay eq a os 4-2 -a ~ n m- ~ y y ys A. F4. rn seAC4 a/.46-A /d / sea ec'A A9 sf-os.dsm u u !~ ' JJ4MJ E-4.. Y.c~ A Y 4c JfSPS'" $1" (/ L mA n J M. 28-6 r 2 224 m&' s A-M,-w7 f 1269 '82

........:.=.~......... PdA 444 4tN CIS 3 7h 7 n//-a-Ah ,sawL1 J A JJ 294 -M .<n y & 74 4 6 w & -h &dM s 6-A d~ &./ o .e n/M /b a w dx] mdsda ema/d / $ WA m A. . 995 //-,/n //7% /// Jk V ~ f J/ V D J A- -s,A A -JJ v v e -//wdf ///m! /E~ se /!bz ' dm 8 & 3 v-p / MA A ,m>A s d o.# A%J 2< a - j-A z M 6 1 x -- O A' -7d4d# A-wa ~ d () / V VV V z'A mm A"d Ms~>/A. A r+m m v ur .-u--~/d 541 Ja g sq k & ~-r-J eAa onJA da -a~ 7Jha /%A e.-M v v y c,4, J A a M d-A : d --sd 4- . 9->m-cem e a-A --J >Adai d) d'- J/a n 4 w&A a / es Ek-

6 rA & s.s.>4-/dV /raZu~d O-M

% Ai /n.1 4d.a % s A s. 2 -s ~ u m 3 s_Af pro 6 r_ sin: a n A-f % )

2 A

.e- % p.-~ 2 1 4.. p/./ ap M a.d 126S '83

n.~ ..-,.s... .a..... ..v.? . w '. . ;'.. s'. 4 ~ .w. '.. s. y...'*% 2. a.. v.. I saast or coneewers oatt

e. r-s b

CwttstS Saf* // h / Y lY ---- ao /* d U d' LJ mAA'm A r A s_w7 s L A, .n. t/ Jn~z /d L / f xaA~ Ja. -%G ~ m ~ o / A!W Aky}n AYN/.rd 29$ def A's nwm 27/ e r gvv g A/./ wJs DA 26 &=d.J.Ae o-p % pq 9 p-p-na aa s 3d cyryLA muuMsa f ~J m-wd A y A & yrs //-- Edx. dd. e--A /wr-cedsx d-6 ~~-. / f f .sde a 'smsAfd ng&L.0 alms -O/wd >Y# /// &) Yk w -m &A wswm) y /f 4%64 w -~ -72 Ad/:-fdJ <r7' x.# s Y/ /#4 Jm /),fY/ b N- -- Y d G' Ja d A a f n ff. 4 / n p :c 2-pec6e-L w, ay 4 ~,apaq+upp ^ /~z A s d s/a w; 4,s f JA, n 1269 '84

z..z........s-.

+- ~. : -= e w. ; -+...... : e..a. c.~.

.. ~,.. 7.. c_ C R 6 A.,. /s a ) c a b A J -s a /4 1 yv~ p / r /s L22). Sda m 2+ A, Z/. A 7 m, Js 4 M A AA & & 1/ D M - 6 ~ // ~s -J',a J M ~ct A /- 2 -uni o Ls f // / w J / A sj.Wab> s A m.s m,L..,% ,py A r/fy/ n.adh -n-m u-zKs/ o m A m /.J J 2 ' b A;' aA 2/d e/_-2/ d) A gd47n~ oLn M e e s y mAk ms/. w//d xxco6. g 7 e ~ d. 6,;L u. 6%. Mn fndk Ad-4 n,_ a &AA-> %A. / d V ama % A A4 &/Af A &s LocA 4 a 4-kso o~ / / / pfa //-c&/J a Gr n d ],G..M aft A o "d' jn AA AMw o./ soe x s e g ~~/ o osrn/Mn &,, f a n s 4 3 o-J i a g u o4 4-s-a ua: ), XeQ ~ g -e. x% o-s h.x n-n 4 a?/ cd ~ f] 'V y V 1269 '85

. - - - - ~ - ............. - - ~ ~ - in._.. .. ~. n w' e re.e cave // >>n- ~1A a~/ n .nh y.Al, / c 4 o a m.m. A 6 so-.m_u ,Jx . a. a-a.7' 2s' ssbb p-, ng-xg a .re' Aad af,A a A m, 'b L / i or,,. ;, ) u y L a M & a,, .L -,.i s cL A->a a s a i d 4 A-AJ A && nJ Jud</Jd-e dr n2 auA 16 A As Ax a <f/ B h WA . d.2 > s s s W.dr /[ $ 30,-)7<Nu k ///./ S s $s -L- -m / y. Ad M/x - L di

A s A-A),m,_

/ V .4 A AM e A J'swnAn

c. M /

o e p e r -:a &n>Jx A M MA 4 - As >S? n er /s/]/ A.+ E-C&&Y Q7 05 A x /jl 4 c/ -Bfd, 4 o-w L. e Arn en d A /> o-A --nJ /2-f - e% c-a a~,.Ja eoJ /A oA-i- p 62 p<c, dN A. s'? n,,'d's> ndlWe/ m f f V ff / %3mi- " 1269 '86

..... >..............,....... ~..,........... .... - ~. >........ ............:. x... .., x s. A Os of&m n 3/, L b /6x w d r-M- s s kJ / V n i.4 % -c-Au% h mad / i dy A t'%M] + a / .4= e.ca1 d w a m A n 2 J J.- n-V f a se-mJ AwA s2/ T',,1, A~ ' L.- /- g a . A7' Als . J -,,, n, s M-nk /n-IR). /// ~b sd /Aw jw /EN' da * ? 'A' A.- t' au,>. 2AAJ m?MA 2 a AM a-~t n ..z. j j - e y s v s/w O s m ~- f f ] A s W s ,A s s. n r - / >* b-4,me i _n4.. / 4 -f ALy-A s-# w 3L4J, d.w/ xurm-4//s o. A mA Ad-4ach V / r m w w 1 d,d #sJ m'J <>J, a#AMG' s:a.HJ & r s 43! J J-- / GdA< 2-Ans e/~.~ 2 7A m=-M j e a-:-eM,oA/ A-+-m ->ex.-J M A sh // ~~ m A L ww A 2/a e d A 4k g AG_ ^ o ? O v' 7 DJeJ14 w n :-/s, A /c% s/x2'A # L ffs,- o s a/ ,sx.ds8) f.r-- /M &,- 02 & !. 6 8 /:4-A d. s:e d s/> ~ 1269 '87

.... c'. ' r-t:c &:i.=l...,?),.:q^. :

r- :-

.~ *:- .., 2.s.. .-r- . l

h.

s. 9-Nl eo ... 4.. - C-) ~

=cev e o

6 c,,. e '~' / eL &r - s, ~ s. Q.. w a c/ z V f } e w '~~ a ~ l h_. ~, m ~wW i a a ~, I / mn. &s ~ -c-o-s d 1269 'BB

~~ ~ -> ' +- L a..%...w. ;:- = > - -~ =~ s x ~ a ^- - ~ -' -~ - o.. .. 2,. ..m / Y / Ad /~ J H/ &WD d r r f / ,W $ /U./x / k-AJ /< &bSA-) / wd-~- . ~/ / f V c/ sdALJ . LJ e ~&&- - /J/t -d. -JJ aA: 6 nsad A%7'Jns-K e c/ 2esm -, Ps.-JJ s/s.2-w AAnJi ///A / wor 4 r ,8 sju%~ C/4'fsAs n o Y -7,ux ]. w}m r j i / .,.s'--sE- /$wsr 8s /:c b,s/m od /d'ol d /;-s f V /k /- ~ 2d4 - o,1 o//n.,J1 ka A s9 s c u Nu b/M/d //' ?d. t +"< V /de's/>$L. ' s 6 y /m,n n~- si.-> n J J,u / d/ sw- .2/ o.- o i/ / 6DA lb a./)J $.h. ) b r-b b::s-i sl<.--s ue). n / /r -M' m n.A,L,. A, #9 n, w h x 4 /% _/ &sfA d$ ./- -$ /Ms. s / s $ /?" "I Adf /~~Y Y f / V $$/*9 $2JJJWJ 0f> d" JA W8 NJ D 43 1 :2/. 2 4 S L J P r.ea g / 4 6 - 3& J 3 A 12 ra, w m. / d- // /M Z /M-udw /h//x /Wb / /ss A / i / y 1269 '80

~~c. ..;.. c..................... - ~.. ...., M. e.un.~~

~~u. *;~~
~~six/A2 MA.dd,' s k /L A d y n- /scs) o,~ w / g / '/ // sa m es:~r- /n n-AA-v' C/~~
~~a em~~
~~,wk a X/~d,Anh vy d L 1--sw dn /n,~- ./nd J a o v 7~~' A-s1 a% adAC/>. A /Aaf m-, ^ s Aka n -u -K /%,- & A 4+ trAA v p A-4.a sk &m A /-~. A/62 Ar- / s / g '~y~ &, M~~
~~A~ 42 JL mA A~~
-A -- - e,Jd s n wAh. r }A r.//fs-/m //' jk s e -- &i$2/And A m s'/ ,/ 9 p' n d es-d Jr -J. / A w. b,,. f /nk ne nWJ mw sA a 4 as -n n-m u -- g fr-y , A. nf Os-d bsl 8.,$.b W.-uN ->-: J >$ A YA. 67 + A-3 J Ap'- hy on '-.:.J,nna ~ x # eAab a a C1~ A q. 2A s-s ,y 4 - 4.c/6 /m dz-e, o n & f d4 m-C/ s &Js f J A h-da a u b m A ;. w, a G, s f'Y /' /j w' Ys-YYj]s $49 FW/Y/.A5' //U0Yn./s s_ d / 1269 '90
~~.. 'v.4]:'isw.. ?.a..:.R;c.c..?:;L :4.*.,.3'.M.!.' 42.2..;a1.:.i.d..:' ': :.. :J.:. E..;t:.: :."l. J.W' '~~
/ g. ... ~,.. w A jag 4-/,// && .c -7' sy3 1 % # A s /)' A.se /3 2 /J.~ b-M.e t A p / fj d y r m& c sL~,s a f ~ o J!-e-J Gio.- /M. &Jn A L / N R a u-x s rw w s n a v / A,) a A mzh.s d. -u Af~n.2J &l' K ~ // P a dan n #1 ~- aJ~LA-J-4 -C A g iu. /k &2d rm A AJs.-/ 4x & e y i A J A s/> m.~i~ _ d fr --n yA V / '- (/ ) Q ' -j 4 *A s c. w ] A.!-n A S~00 e...
~~o..~~
/ V Q 4sa// //L1, m -ee m c-s-J //. 79-5 ' W f / A " g u ~-l/ ,4-A /h 2) A & sz.ern .h./ A os #4s e v .r/ - s/er /m 14 sHo. -//? wk/Ls) mA A // o i s A% nA em%# p,s mA'su/-9A JAE - ,M dx-c f y.7 ~ mpww af x dG/- oa go /w1 a&t 2&ywL ~ L ,m w11 1%J & gnAM n.<-/ - m) p i WJ/A f /'~ W ///JA2./ / Y/Mo 2 / 2 / r 4 <; 1269 '91
... =.............. . ~..... u ... ~,.. g dg tee e. o ee Y Y O NF WNM = '/ _ JA J j /1,/ 3 n f r A 1 6 J Jg g a /.a 4 k s o-m d4, J/% '-J'82. D-AM m / ,/ '/ A ./f A gm22, mlef,M b w) sn'L t;- n - > mad -A ed w f a . 2. s,/ fs r W A-- Jd i A cucc ~ T ' Mis s-vv c/ ~ or aMGLJ />x-66.=;.<9 pA. eff oithxs /,/o-s s < s < a, st ,2 >x j .g sdd>YA - Yp AM ww f 5 ./*- f J.~.# s s s o--- j.-m sA d 2nd. e Yjt' s #/--- rd)' lJ. 4** /s.s'
~~7) /s "7 $m' e~~
/ / $ A h.-,r/$. -/ W s *> -'.s )' M sl o..w / fV/ - 67l.A; * // L. ' A,*k- -W' 9 O C-Y F- *- 1. .* G ~ d /~ s, c. Y p ) s h lN. llrwp /Y. / ta4 A s / /~ Y / J" $1= f M /./' m s; ~~."s' ' M J s ( .n 4- ~ o.Al 265 ~ s .7 %,n 1 J/ D. - w J G A', . 6m e.LJ / sh/ m 2f121-l2 J-i.a. -es a p w s a 6WJ f'2/ss)b /w1-- s/,) b~/$sL-s/$d //// ~ . / '. s , j v / J. , g-y.- c svm m ,,,,,s v w - - Q ) 9 f D' O / L... - - i
cc-- -- - - ~ ' - 1T t- - EJE%Nt *"N"-4r m - w m,*g.71,, -. -
~~- A es t ' EN Of S 3 ??)~~
~~smart /7 or / ~ comewtse SATs eweewre e~~
~~TT Ebh_.$~~
~~Pias4< Ms/ni .5. < na E/wskmr / .V - Cr omb A rsb'w b2) As = a v ; -e s~~
~~ffe w / //. 4 A,'ui /',kside )~~
r7s %x2-/ L$w Psi f (iks,de) f5? He 4 b- % - e /.'e.- 5/a G // hww !b'a 5 v 1e ve / SS'l PA* / Se n u (J/ah / Ltvp/ ffY %s nf 4 A 7.s F29 r A/ seism fo/ Jurst Ass /ro/r/) f/ 9 s {.- sw c.,,a : sew m anA -> cri V /s oi n ? %/w (i*!" /?r) M? ii/ R w_w t/jsfr/ L.n/ res 70_lg#Assh /4 u) _r/ 7 P n 4 / Ve.cs e /.' %ss-/ Find Als ?' finsta'e ) no a + Lu h wb-(A a4 cs u /) rn A4A 1 ~# A&? p-]s ( /s# po'%f ) r0 2. $~ us A-liv ? Fue/ /hi /& priN5l J ~D C / $in u,x?) ? 99. 5~ )w', ss av-/ / I g _q l D 'i Y] s
.,g.j g, gg,.;.m._.,.s s...mm,.. .e. v. m.. c............ _.. r._m.:.. : e... n.w . ~... s.asr /P .r ....m. urn g L. ' e..e... Ed/s d2 8 .f / 4, &// )%ty 7~r.usn fuws (Of) e O r/ 5 /vn .S~&S~ ^' ~ /%WrS/w e93 ro eo an 3/ a s ai 9/><su rize Liou,d Sr4 StG .3 Sea:/ ff3 S c. Geodusa.hs 'r 4J;~o AM/ Bu s &s.suve f psia ) : FC Pun; Dreg .23/9 n,re Rib /w . 2ss ne esa mo .x G Mesw so vo ( - g S6L Vs 6 5 %, c f,osio. ) : .Pressue;se/ a Too / _c y'e c m A' au n.bo v- / ;;2. 25 a rt.S$ U v; e *v ISAnw 3,92a ] ]4lvrM3 [lE~ ] /O 9sd h/$f u Y? "E-~* J fd bd t/_' k#A e6 l%~d 0 / ./. bo Nlh n 0/sce.r vi '-es /9A0 . &.. 47.br/ ll9efAl O $9VP Bf lf,M hj$C J- /va //w 8/,? cu vr_c lyris).' Sa /s h I,,,'echts Lqe /600 G 41 ' ~,% % G r< 4to AN /7 70 m L-W c yp r.r p n x i e n 7n. y II ' O i. J,
e ,s 1 ';aa5& En;t%3 h = ~ I? .. m { *.. .. ~n, en s 7216 3 a & f-/o&A / % dos of Dua~ &si Pe~sv / U sw .c s 7 L-p,.. f, j-o,i s A,/,- Gd./im 1mt 7 - ve l Pnss. Dw/ 1 /4 Airs / C;<eu/,kis, " p-Dn, -
~~.it/~~
R-Dew n // .i ? As7%/ /';<a /s krl S -I,a S- % ? 36lb >=, // _2 ka;/ en Dxpin .9 -Doen 7AL/> Drsir7 A /%,- Ba:/ks E n.-A, .7 -Dser Sfshb Emoh f V f ~7"vap < s'//o EvsA. S - E e r. S-C-ex RsA// ' W s.Y 4 //sMs/ ArsLAw /b A*// s-Lex 5 -Dscn Fu// 7 x.//,.,d r:n~/s Aw fu// vh.}b _T-Dn x 5// P-es.s. Lerr/_is pwsawan-bre/. ~ ~d. M>us-e/a An-PV Le.ve/ is re.as Av vsste/ h w /. ._Se h/~A fr / <f. i5 <* < kis' f!_LC f:)vf. p . c a m, 1:r,/ i e_ < Asw amw h/ 7%- /-n/. E Der r; /. s/>enar:n.. se _p.lso >o e,'y 0 S-Oser. s'< < /c:.<.dy/,% e r.*a si% a. <-/sw <-J}cy. .s ' b'c d t b y,_,_e. .5hrh/o le r;s <~/,s i ^ q W f / d ~ 5 .E. w, M ~ e /s / xies u / _pzs.t.1:/ e c.edwA2p _d fsu /w var s-/ < 4 n_. 4_y_jll-8.u__ Sw J. e 1 ?'5 ?
~~9 5~~
~~e +a 4 =.. "...r. ~.e.t'... ,.,gg.~~
. 4 e o' e *.

e.
~~s.4.' e* S a'E ET O or CatePUTES O'TE 7 etstCetO SAM 6 e e& <-ss,i s-s 6s <~Ld 6 f M k es: v a/ A. $/s c/.rv p rrrt/ /ser/ iv,'// rs.r.eS o r>2/rirs o w 34& 4 ;ner~_ss. e. x-~, suun a hu.~~
~~s.. M.~~
v y n m k 1269 '96
.'. :... :..... s.... J... :: *. ..... *.a. u.. a.:. a.:.w .. %....r.. ,..i.. .. c~ s. ;. :.. z ' '.~ .': a;. - .2/ = b Y. h<6 r .w 2 E. C D 8 il 3 3 F1 !3 C g-7: 3 /g y d5 i i g 0 g o" Sl: e m , ; bo
~~8 be 5~~
h) g U l :. S S 9 ja di3 E E l .\\ .,k 2m cxn i P_. r 9; - ..,,,a 3 m, ., ~ g - e [,n -- -J y'E.E~=-~E ,]{V,, s M-e t .s ~, m___ ..__..i a .c c. .a s.. s f--- - -,,..., w.s [ gr\\ --N """ ~ k N' ~?d r i / ~ -f - a 5 (,,,e,. [ g ::, -- t,, l .{ = 2 ,a e .ae s ge rs iaa - ti = F. 3 v p gg i sg p-- % y e,- 9-sa y, /. --a [i hy .= 3 M 2 5 / n wJs ( dus'
~~.N g~~
~~3 2 la y 9~~
~~i..~~
~~ehVq e C= - -- r- . i. K, ? Q a :/ nl[l ~ ,i~~
~~i. i.~~
~~3 f ;l !y" .cd'/tj}ll ^lI l l ~ -~ ll lj l l 1l 1 ! 11..e y, J 5 a w l, %g } F d gC r.- u , g l b .; suli j m ii i 3 c=1 i ic:e a%m w. u n g g W C h l' b#g [ M i, ' ', $2 T._ Y:,.e @n. c u~~
y
~~-uu 1 hs s \\ .g' N .e " ,, t D' 5 I 8' k .. x* a 2 ~ W a 5 Y 5 Y o% { 6 \\ E 4 8 a w T~~
~~y P00R ORGINAL 1269~~
'97
...., x.. e=te.e can kna% A VU AAbs Asscis 4d us:% Poc +- Loa L-Modos o+ Do a. nJ 6-vd U ay Sv Von.,. Stua // ErssE /ACA v' L J+ d e A 2.. K:1_ d M / of w J _ ty y.sy,_ 1269 '98
d : s o :.J '* ^.'a.a :. ,.. ;.. %.,. '. au :.i..::* :s.' w. % s
s. * *.~o e s

a... :r L..
.h a.w a. ;; . L. .s'.1.....>.'. ..v s.; s 's.t. Wa 4ts tee 085 3 ??' ...., n.. n o, M e-eeves este 2 As4 1 6 As / 6- / A~ H, A<r.+/ Ora.W ~ V O' u,; M Lwi w ksm 66/A,, ._v P-9 4-- JJ-/4 /w-> a Jm a. An% o--> w/mb' 3 a-A y v mJ 4 A-- xB A L A % stu f/ // / f upnJ& b p mf (ptb-a, J Y emzynb. /?- m a A d w J o n - ws dwww-e e u - Aay [/Kr N !-8.b p/ )62,8U -Ace x/mA Ad&& a.ex/.-a. A s-6 6 / / V cy/}.
~~e. a,4 mm,-g,m n~~
w' h ~ ( A j e A j) 4 n a7%, a' 4 'sm>&& e A f p x w /. / a _ A 6 <- % J &A% Au~4. /V lp0'o 'og ~ 7, e
mi8 e e ** 'e ', a 'ema..h g ' 6 e', e 4 4 e*ge' < 4. '*
~~Eb ' e's.e W d N 4 e.'h o'e aP fM *v e de' # e h* e ge e e 'b ' r~~
~~$ dd 'ee *.= b # ed 6e L8 e~~
~~D e*EP b e' e f e ed "ea8e e~~
~~a 8 e. o "la su i(* CIS 4 77. ..m _2 9' .(~~ ..,vn. om es, w em d. 2-sm, An A-#4 1 wDL & a y yw- & 'f'b " N # d"#W"Jg 7 w-JA. y~~
~~e. %As' -~~
Q _ a t. >e / f l f A A ,d-A w w w % e Jo/ & es,<> J -A Ad dd e e r .52 r-med. /m Af d i 8 r w x A->+ h ) g/ / / r i n e d ' A E f /2 L:1. &W awNu b o m .x s a -.( - whiv h d:o ea-n-m A. m A o% t/ U </ MM 3D&r. ir W Y HM Jg./sY3p)$ hmm ~ & r>9 j nJnA/ sm as ~K J enK _ d V A A n)neAA'~ f N wLfwml u .w% 2 A4 4f Jg ga .y 2 b aus_AW &vd 6 &Aa-LavaA6n, ' v v Mn B 99116/ %;;s / if.ki_.t.syp_ tfghe/Aw ~ c/ \\pn oqq
... ~,.. m.c.
~~n...~~
a. .A 444 f'- u m2 s~"/> ~fn nm, />-wa d w' m A A &-, A a okh wme wme-4~. n A d%- <a y v v .Ak.d / A ss.a t e. p -A. 6 6'% MJ 61 AA A w ./en, y 9o- /% AJA &/_,-/ ) dua Rdif 2 2-e-e A~A d4 Aw/a a, <A-=u - Amsd - G f / m c.[ -c. 2,.A / J rn Jun-LDa r r i 6 % AL # d a rr.s & f ek.d-. & - ) i ga c) c/ V _p ' x -n A a & n d y.u m-m A cL /JM om' A. ie
~~. h' l w 2 4,/ )~~
Y 0s Yf //' HYw 62:W' <. ~ y / o a en y A p.44 A s m -J A f e 39 rr ~ J Q,2 Lad m ay 5 7~y 96-g s4 n - ~ n.k w-,) en n L r p r s y A fr6 " "i sal 2 A-l'ex sA.:& /21-f g i .... ;. =. :. a ;..:..... .~ ..~ -..=.,.. w. 1269 '01
...c,,,,s,.-.-.................~...........-.....~.......... ...., x y - x4 s&4 ch~L AA d's% /xf Q 7 d // 6 Addb, // 2' A+1 A> A su dsu f M A ~.c.d
~~A M6 M.~~
/ P. Ik w* j Y2 > bh J/Y d A > so c v 4s.ru' -m6nf Ju U /JU A1 &}ds~ p r u s As, 14 m A m ) 4 (A.- s& b-A -,.:./ k s 4 u dk 7,' /w // / S< - /m / &7uA ds ,c-a w s. Ads A-J'm f Q ,A A:w'ys /p 23m,1 fm.-ts //A 3g. A A J.A6 re m- -a a -r-4 -s m-n nJ2-a a d <>4-A du wan M-f- d c/ wd /2y~- AwV4 pu~_,_ e_ad a weg' 2'Ag wL%y- ((mny-dw e ' dg- ,yx.i n " ~,;&.: m-&_ x '"=ny,) m-M m. A W4-es Ja.-d n A pmq s p lJ et a pA - 6?? c-n-n-..7, .1267 '0?
' ',.a.a t, u u m - - - - - ~ - ' ~ - ' ..., 2 7 g.= m 2 s/w ;/ J.n.- b-A >>A a-<.,_,, ? A//WP E Eus. Ak/ B.rseva/ Deeing Trec;A r-Frw u V //ahm/ /*;rn/s Aw '~ A, [w &U;" ' Ab u / m )./5 ls)s-}u $ l$ A Q. W $1 v cr ./7*#s /R O /' A &b' 8 J~W::.Y / /Y~ $b ~ of d sh n y d x 2. kt s u w s A D A c A w 2-vv-a e j / y A />> Yng Cef g we -a n s m,x + ny Auy amdp.e-4 t ndh aew.-u o d-m A ~~ -a s. x/; ma =f. / G p&endl
~~ALD a vd 'ws ufas-j W~~
~ ?,. - S 5 9. *::~.l Y- '<.* [. f 1.260, ' O 7,
...., 2y_... courvTro sa's ..m.. o w , f N/ bN/h /AD // / A -g a>d s% .pu M a s by_2 e. 94J3 L A x & ws/J.aA ec.A-/ n,wkJ. d uo x 1% e // s.o76 d L A c J A / d e~w &L. G Afsh A ' 9 Af 8,na/ b~ avs L% e _ L. -' U (/ (/ a. A,2 A .f>J JL n 2 dnn, rk r A L.; / /s a AnA 2% du-4 i / / &~ fAm W& - s. f6~~2 4 a n s J.ea n As4 /m s
~~A"d' /*^'~~
* "f"j " ^ s d s--/6/ <6fA 4>Y L uA.s ws a y d A sn Av~ J M./, 3 s o7 e A ~ r sLX k c e w _~ A-w%Udek ~ r J/4 a f, a %,- c a z w j a A s,. e !269 '04
2:..; :......:.,- - - -- ~ ...., _--. e p. .. ~,.. ~ 2r zA djbx AsL LAA 4 2 r (/ 6/ f c/- e/Af A Aw did /dda, N h // - / ~ O m. / L J L A 1 A s d, .* x4 nL / ~ ?)$ // w /b. 2. 1/2 Am wA& ' n2 J~ ~ / / OC&2$ $m - 'O .s' A Y b s2ss $ s &'-/). f r. n A. 'o1 ~l rru., &d4v/- Ofm J/s sAWss:s of ar j r, g s onA MA62 /4JQ As7~~A -,L a J 2~- - e j g-p r/ - 4 an, d A4/- 3 A x- /m cA / ,/ /~ V / / A O// 2% m g ar f$ %s/w b j & l / W 2l ste n f W f/les 8*- OA/ dMMs f/ % l}J6 p.xxx> /-+ YA A y qw--sa2 Auf<s, n. /d Jm 22-a N JA n---~ <>s/ Asf bye' /6 4 3 e./ m 2 2 - w p uu A /wsc _d 126? ^'05
..., yo y_ c :.- Anfa i A mm /od o or w / m L,1 A n ;6-AJA 2 A.smn 4 7 A-}es/ f2 A i;&n,L- </ &A A, x au c6-A (A/re 2-ei-i e t s.d. 5 ~c d.s a./ A,4 /J b>, cw & - s p-jss s e "'y 7 9 "^} "5W" A "'A obg6 a~/ A Mn A .7 ~~ wnA & /s4 WM. -rik n. a k.. R,.: rsdm e. %M Js, AnA AL .d-u.A-A /mm t y ? --Aa inn-6 x a~/ mas y . vAAs. .-a A/A -ld-ra m a A. $ W h // !d d Y-Ac-') $ 1 b $ AAYJ'-se Ces,_
~~A c-upAAf &&,4%W -m' 3~~
A - A Af~ d-yA. -/ 7 ~. . _ _... -. ~. _ _ _~-- - _. 1269 '06
.n..,.1. ;..:.a.,:n.w., aa.,.w.a.a. a r...,. a.... a.: &.:.......:.. :... u ~.... : i....,: w ... ~,.. e ~ AG6 ,( /M A/6mm/ /LM- %;Aw R-r U C/ S,, Ar, %
s
~~d s/ dua,/nha ~ As'.ch e~~
G. 4--.C, ns) 6) cn &-- -zt: mn A // dd A. m/> s. Am w.a / R m o / 6' // An.A. d/A Au /.ffsul /d. r s dA/2 a b. 2.&-- a n A wrJA a>- (. / a e.,.-e. A c/AJ. A .s,J.J, ~/ &Aw' -,,ss g/ O' 0' -rX~s/,, <A/.r - f a fx .J D.rbd hk. d d / e. AleA w./JJ /% e d-> ad saw wd%. f f ( sin 2 n-es.-u) #m AM xms &A Asm a m, .-@ aG w k # < L p
~~s,-. # A C X a /- e.~~
/ d. Re-a dk -ew-]JJ A' d w'w, a s '* ' As._../ J A d P' sp s e'f y,s p /. r * ./.o / j w / s-s /* - 'e -s / / / /Y./.2&m m/bssj/Yssf /*
~~s' s ~"~~
~~"4lfA / C. * ' J cl d } L- (s 7 0 1 7 v / I~~
.3
~~. a a:....:.. :;,. a.:...... aa n..; n...e. 22 ::.. ;..~~
~~.:: a :.2.n.,.w. ge. :.w:-~~
~~g v . c A /k n. -6 M. 7 n fa /n)-A AA o~ JJ A V wnMs n J~J A A / a ~2 AYAJ. X-r' a~./ wJ s. 57" 6 t-t. p~~
~~a. L A w R x4-1 A~~
~~. o~ (l / V il / /W- /14 /sv .J-n~# A d K-D s e m /s a~/~~
~~a..su e~L-A~A A of v~~
~~i T A-- M a d A <- J # ~ asa. er i e E. Bassi n2 / / a%m /,w Aan ) x1 & --D 4~~
~~a. u-- L -A &d V~~
/ /m fsed u .knA,2. -) a~/ A-6sacov p g e i W&A / 4*Y*,.s // 't.'" 0.L "M TJ. / s o V / // ~ ni.=2A 1A ,W &JM.J //s a mA m m oen- - & 2 % -- ~ o e f A e-4-w/ud M.e% mi i / m? / / sd s~ AJA s/A -% sn n-nz. / V A A4 - 1 4 4=- n-c,-Mt sL' hv j r i e 1269 '08
= - u := ns-i.....=~~-w----"<-----'-- ~ - - ....,.23 r cessevvte sa,a _ au,
~~e.. e.,e n~~
~~, ( san'd as/ w i I 4 m & J e A A ~ / / A b f / f/ t) d & w_ / mlh A d.sNdAid 7 a- < rt z.wx r~~
~~j p~~
Es) d>> > Omnd22./ stJA/./,dw" sx _,,s sk A4 dn sa m 1 4/- A A d,n 2 u /91b~*i,l Aisswh-A A / >* ?) /k6 a.) () / G~ 0 ,.'/.~ s?In-- s;A J m-, nkih. ~ /2 v o w d - b af A4 A,A/4? A 4 2 h ,/W k Ws*/ YY sdsW S. /7* / s Od Abd Jd W"W s/-.a$ ) $ s d j n~ s c/ 2. /~ n/ n ext) W / D 4 /.rA Aman / b% A m AJ/.rba 44e/ o v Crn44- ~ Ys,7'$ 0.eS/w I/ssy/ 8;s uw 0/1% //ae., / / O 8 / /*J - e-5 } b W J x.r-/- W 0 /nw/$ m) /& 126V '09
~ ,s. : .,,... J.,*,.;g..b. S.'If,,
,

.. r...,..
4.,,.%.6.t 1...,. .,,,P ..,.c-- tra e..rtN *t13 77: s=*rv er e .. ~,.. w .., n, i. Af/a k/ 6J.A ~r/s A PA / J I e 2.4.a_...s. - 2/"f]2_wfm Adm &mx2 a.- //b d* & d' W ffs. -$._$,.- fJ4~a' sy, / a - war m 2xa se s r .fv -M/w O. r s J / ' W N Y sjs w Y 0. -f d -c - a f g-ScCAdL// y Ad /d / y / :- M-W-rof sn k na s wa a s & d V d j. m->,6 /<3f a oA+ -s - A b_,L w 77 .+ i AAJ C-<'. Ym pad 6%P A - [WA $f fAfP8 W 16 &q AAv cuid~ < -w a -w a n/ --a yoA / /<n ds s x M M /da ~ r e a-u a
~~'2L -,ArYYxd f #^"h27~~
~~&O e d. J-- J-A # 4,,~~
WJr- //n_6 m f r / W _ e /, A.. $ w p >- b -) 1wXo ' 10( U /
) g*s.3
* " ~ *

~ * *

~
t 'a e's PV ....? 9 = C OM PUTis Daft .I ~ h e=ecer; e#t a d /. A A 5 sde A hf J> om v v szi~a wsA xxA AJ d kJ. a r s s b. Pse/& #d JJ w&-x b h/m (A sla w - w % d-JA u2 4 ) u a &~ cm422 A A JD & V / / / /Ybs<. -A A A>A. / C A A/>b b bY Ess/D._ o /D*-/'/ 4 -(- / e,n-n,A 21 A snk ma / el-2-#A ano - 6A -4 x v Mnu n a A d u c.-. do%& A.7Jm f Q &Asm-- ad dd as A, 7A 4 V D s s e x 2 s $ 1. Os d-W/-ssd W de-d. J e / Gl. Osn.n /, sw m 6o 1 ON x$ JnD sr r e o tow $' /57 M PA /fA m %d e owsm,/,- u kJ YJ /. / b Y / 4n /,,/~_.Jffs / /J33 's + e o s. x.# -d /n A w J o % .A ddd. / 1269 'll
.............. =........ .............w u .. ~... e. s?-na J~~ AJS A enL%e.~t/ ~ ow,an,, -. a 4 s ts 2 eAnj v r at, ,1 n&A s wA x2 AJ //x
~~- &n%.~~
c. L, s y) an L JA AJJ J Ji D r- ,/ v o n AL.,>3) 4 - -cwd A on d / A &. u.- s% AA enk ~ s c A 's s 4 7 - / Da m /-4d /2,msa/ L r%./f,6/d,m~ U V H<-he-Jhrdw C c // b S-ennt u g ,% A J r i J h .Jn' An, nA / a. y > :2A&'/J x2 mZe s + J-J J oJa 33 a d Ay Ad J u,.-fAA A n JXJ n.# &,J / r 2 n 4 n. n-j A j- //n' do- &&LA.; j d' A cX d-*-sal,.- c./x?]E /% m J g g j ^ a g i 1269 '12
.. * ~ n::; ' ud.. ; ;,,*.;. :sO .'.d.'i..: i6%Kt ?h,:;.s'$.'s.',.9. 3. :.". ~.. >.w.... :,..,.-a:..,r. ;...~.; ; ~ ...., j_., ot .g { e... .an hsY /M >yb h Y> b4 V / ~ d - %a e w d a.e h-m. /# M O '_*s W W W 15 e c/ a smin-a% AM si >>VM a-g 2.2-s) N / f' 4 &wmo c. Ark d.-8 J y % ( s c s),;, 4 </w h z w,-e:.4 A / d e w J-4>sb Ass.a~4 / o bm /b sA W 4. / I, LA s.sm) ' d. 3% rV>m de mA.8 V / 41/z/ M( & ds//A J m L b i 8/-4tts y n b. ~Y' _.f:z:2 n A d /J'". Z *' *'*J --- - s g n L, ( A m p. u - e-p cr =- + - s 2) 4 Jn MARJ). 1 fuL~A -nj > A '- scs ym o d cu/<-&c4 .bcL m enz-zh /mm a v' J s-0 /M$ &#sm-.'d
~
'.'/Y~ !..Gb"-w Y c/ //d Ae-p-c-- ax. c.f, A & 2' /s u /w -. Bo ;-m zW'n] A:2sA m/ / .~1~ r:r) /-r A ScS. Y l I l m) b' n 3I;
.....e%...;...=,. m:. man-:.w.r.. r. as. : <.: =z... :.u x~..a:. c:.w n., Als l~eS A 0 sp% um)) /$2.m/fl lDCA Id 6.1 W fw CE] d ~ ..a e,.o 4 AJ A s% as->A ad / V
~~f b~~
~~Y22.d-w l /A' A &#W O / N*/7'r a s o e //pA~~
~~50.///.ke_~~
~~Alas 8~ ed sf & L s s a N J LCA_w) Q h/> W /u'd N/W Y D h.A" /2 xa -~JJ g,hM6.A4 A3sf A 1//w' Y v/"* JJJ JA** / O 7. Omma~~
~~o. m A//4..wh o A J~~
~~G ,A j f-o A _ p - x o u y d ' un A- ~x =_ - a x.n-s w y- / num x% M/ A. ',L*/<2+- c/ m_.i_/9 d G f / /19s) sws sdsb PJ$ esW4$w s L-/} O/ // O A W/ ' Mh2 Of 2= nyW #~/x AgA (u 4~ ~ y-2di y~~
~~x4,47 sp e u - - A a~~
~~ p Anp. Sb ] 3 l il
...x......... ..n,,............,.........~.~.....-......-..........;....... ... w Ad n--,J .2 A. s-i.J ekoafk. v u c/ /ssa, A/N xisA WJ .%) wDs.- p.o$- LA e tf 44 ese sj.a' n e,k tak-l22 Y Y A l As / /Ax43 AD An.L > #AAJ. 4 M4 y /i s du-AJnx- & m22-an& M c/ >&s3A w.d Me,r././ aq. t M-. \\- .s. Dn JufAfsw.)A b Adk dei C/ 1/ / 1/x.A a #b w ~%f 5% M r 4X/xMk7' Aft.et.df m$ m)/9- +/Ys-m / / .M1 sus <8s_ s/W Crbesm & Y //$ / d n -- ( ) (/ f - ~ _ gw) 8 /$ yf /2r J' Ox L-a
~~a. /m a~ef 44 A x-a~~
/ () l--A A "n,gJ'A _p'A-es y'~2 f /As /.maa/ dsm gf/nm -# n~ i. / / 3 y_... - JJ.A% ;d s1Y/M WL A A':E'd' 0A'f / [' st" r n -, e A //s, s.a.) g m o - w -/ - c/ 126? '15
b'a..o'.
[ m,..;,,1..',,: ::;.n. M.'t ~...:;, d. p,. :^4 h.,:~.~..'
~~2. ..... c,.. ~..;.",., ;,, f.J~~
~~s ~ -~~
.a ssa.t= cts s ??: ...., - =0 p, .Sc f d b l "#x 2 mis a s-a n s -n v i r {y 4. . M //d m d a A. d-A &db G V/ f/ m A. Ys AJo'Z ex.s c~/ SCC //d v shAnm wh S cC rms A 46 s/M% i g u v e Yd/.' s /r~' Y' k 4#"f.7./ E J.// $~ kb d**1) $Y A .J y o o A m-is faAu-wn) A-A AmA v 4 'Y SDf*' A&' N N#Y ' ffM" / / E A M kC J A Xho /j s.- s / 9 E e d M e d G/ 0 4m/ w> erg Af Adp ns/ Akd /- / / & //w M. U e ele m M I 2 D '/ O
.::.. a ?.:.u.
~~. i ?.u..:.r..'.i.. ~:..~~
~~..... ~...w n.:. a... .1l, ; .. ~ t.;'...:. <* ;. 2:.. aim.. ,.m ness a m ..., _ E d..~~
~~4..~~
~~.. ~,.. e=ecero 9 Amas'n B // (:. c % // B os /r LDcA A>1s l-et r / 0 0 0 6 me. ILU/ l/ ~ sj u II I~~
~~g. :..... a.. -.....~~
~~f/ r e... 9 l. y r a-C E Power Systems Tcl 203/CCR 1011 r..~~
~~i..~~
Com!a;:wn Cngm.:enng. inc. Telex: 9-9207 1003 Pruve<:t ibit Ibn(t n. Winc:,os. Connect' cut CC005 _j i <.(3 j. 7POWCR Nex2,50 d ? l - 4... J SYS i i.:MS -l i ~ Septenber 18, 1975 l ~[N TD-C2-l g. l 3 k% vy ZI' T'ennessee' Valley Authority I///A.T /;",n */; *.*, 204 Union Building & I Knoxville, Tennessee 37902 ,,.7g-b Attention: Mr. D. R. Patterson I'M Chief Mechanical Engineer J C" * ' ' Centlenen: Sebject: Nuclear Steam Supply Systens TVA X-24 and X-25 Installation TVA Order No. 60-84640 CE Centracts 14074 and 14174 i SMALL EnEAK LOCA i Ref. (A) : D.V. Craf to D.R. Patterson, c TD.C2-117, 6/11/75, subj ect: ' L' Meeting Minutes of 5/27 & 5/28 in Windsor During the Energency Feedvater Meeting of 5/27 and 5/28,1975, C-E agreed to pro-vide nore infor=ation concerning our analysis. of the subject accident. This cor=itnent was docunented in Iten 23 of Reference (A). The attached report de-scribes the results of our analysis and we expect that it should s'acisfy your concerns. If you desire :. ore infornation on this subject, please contact Mr. F. Z. Seiteler in Knoxville. SEP 101m --r.nP: AH CO: U;'.':-le. 401 U3-K Very 7 uly yours, F.:Tdod;e:. 100 '3-K f) SKo:1cr..*07 T3-K Nf I:.:'o:r:l;:n.v. 401.3.3-K e R. Lunp %un, JGW 1 1 ...............,2 a.r.;. (, ) E0htt:11, 423 "L;.g Project Manager i l .,, L'79.!91 T.::h P:. C3 t!!3-K 1 F.ZS.,: no.-.... ic, 07 1.. K N .c.. - Act. om=:AH g_p 191975 00: 17
~~3. **ade, TVA, v/o a::~~
~~7.7, ['.; l-f--j.rJ_' !...d.- - - ~ ~ i H. 3::.:n, C", w/o :t:: n.a.f.:'. "l. " ~]j,___,j._ _.. --{.- '. Cindc:, CC, w/c at: M--,i - ~"- - ' i ' ~ t s y.. r~~
~~' Q { __.~~
~~..t '".," a, . t..., ....-----".,--W!- i j \\ g< ....e. e. mm p y r, %*. * ' t =' i 'g /l J.. l}~~
1
\\.' l' ' c v j7/n 710 ILCi I 0
,..........:......-...,... a.%,,;.,,2 a,m. ,;,. w, a, ;,s, q,,,..,,,,..,..,, ,s ,,.3,., .,/ 'l 27 2L ./.. ~ ( '.' SMALL EREAK LOCA .N In:roduction In a meeting held in 'a'indsor on 5/27-5/28/75, Mr. Sabin of T"A expressed a concern for a class of small break LOCA's whose depressuri:ation rates 1 are relatively slow co: pared to those s=all breaks prescated in CESSAR, Section 6.3.3.3. He worried about the possibility of inadequate EPSI ficw for such brer.ks 'and also asked about the LOCA require =en:s for I:- ergency Teedwa:er and operator ac' ions. t This trans=ittal constitutes a respense to action 1:e= nu=ber 23 of Ref-erence 2. f.: d Sureary The results herein demonstrate that for any cold leg break less than or equal to 0.1 ft2 in siae, adequate liquid inventory is =aintained in the reactor vessel to keep :he active fuel ec=pletely c=vered at all ti=es. - The'.results shown in CESSAR de=enstrate that for those small breaks in which se=e degree of core uncovery is p ndicted, the ECCS criteria 3 are =et and peak clad ce:peratures are less than 120007. I: has been assuced that for all breaks no cperator actions are perfor:ed. A: so:e later ti:e following the LOCA, operator p ccedu ' ; for 1:ng ter= cooling will be irplemenced. This =e==, hcwever, d..s not address the lens :er: c: cling phase of the accident. Long :er= cooling perfor:ance and opera c: precedures vill be discussed in a future sub=it:al. . 1269 '19
..... r...,. a. . i.. .................w,su,...- .:... n :: :. a...v.s... :... c;,.. .'. ~. a. 4; y.;.v. 'Since NRC requires the assumption of lo. ss-of-of f site power, main f~ i' ' f ei dwater flow is not available. 7.or breaks lar:;c t'han 0.1 ft2, those presented in CESSAR,' E=crgency Feedwater (EFW) was not represented and_ indeed was found to have little influence on the performance of such-relatively large break si:es. However, for breaks equal to or smal.ler than 0.1 ft2, EFW wa~s found absolute'ly necassary. 7er these smaller' breaks,. the. steam generators must remove a significant part of t'he. ~ decay energy ge'erated in the core'. If they'do not, then primary side n re-pressuri:ation occurs since 'the break is too small c: emit all of the steam boiled off in the i: ore. . Discussion
~~6 Calculations of breaks 0.1 ft2 and smaller have been perf or=ed t.-ith the CEl.IVEL code. This" cede was specifically written for applicatien to such s=all breaks.~~
I The. predicted two-phase level transients for several breaks.0.1 f t2 and w smaller are shown in Figure 1. The corresponding pressure transients are given in Figure 2. These results demonstrate that although the depres-surization, rates for such small sized break si:es are gradual,' adequate HPSI pu=p inflow is provided to keep the core cevered at all. times. The Saf eiiy Injectica Tanks (SlT) become activated at approximately 900 seconds for the 0.1 ft2 case. Neither the.05 f t2'nor the.005 f 2 cases resulted in SIT activation before the level transient is turned around. For both breaks, the level transient bottens out at an elevatien above the top of th's active fuel and recovers frc= there via HPSI inflev alone. s For all of these breaks, steam generator heat transfer plays an important role. Since ETN is supplied to each stea: generater, an adequate secen. d::y liquid inventory is maintained to suppert heat removal by condensa-tien of the seca: in the l'-tubes en the primary side. The secondary 1267 '20
I gg /. o g
~~3.,~~
= inventory is assumed to be safurated at a temperature corresponding V(, to :he lower setpoint of the s,afety valves (1.70 psia). The con-2 densatica film coef ficient used was approxi=ately 200 BT /hr-f t _oy, - This is a' censervctive value which properly accounts for the in-fluence of non-cendensibles. , To cicarly indicate'the influence.of EW, Figure 3 has been included. *
Results are shown for the reactor vessel pressure and level transients for cases with and without, emergency feedwater. As shoun, if-EFW 'is not available a re-pressurizacica occurs 'which in turn rede.:es H?SI inflow and :he level transient is significantly aggravated. ::either case shown
}in. Figure 3shouldbe.construedtospecificallyrepresent the performance of. System 80. E7W is available on all System 80 plants. The case without ET'd is ishown enly f or demonstrative purpcses. For be:h cases.shoun, the HPSI capaci:ies assumed were much less than these of System 80..Thus,, the icvel transient are more severe. -(.. Q )!aior Assumottens As required by NRC, the following conservative assuinptions were " applied 2 in analy:ing all small' breaks (< 1.3 f t ): 1. Lossofoff'sitepowerassumed'uponascramsignal.\\ 2. The worst single f ailure of emergency ecuipment was assumed (f ailure of ene,energency diesel generator.to start). 3. An uncertainty =argin of +20" was added to the calculated decay heat genera:ed in the reactor. 4. "onservativ'e setpoints and delays were assuded for scram, SIA5 and equipnent startup. Assumptica (1) results in a description of the accident in whic'n the reae:or coolant pumps begin coas:dewn,the nain steam isciation valve.; shut, and the main f:edva:er pumpc s:cp upcn receipt of a scram signal. Y.ain s:ea.= and feeduater ficus are ramped to =cro in 0.5 secends. e 3 a. l 2.(;, g c-
t ...s.- e '.%..,... .;*h.... wae. 4... ..u 5.4 e L s *.: n..ie. C "CL%.... a '.' ...: 1 :. s.,;. d. 4..* ?l;~o.% ,/ " - 4$ e
^
i o ' Assu:ptien (2) allows credit for only one train of ECCS pumps end,ene p train of C=ergen y Teeduster (EW). Thus., only one HPSI pcmp snd one EW pump are available ~ to satisfy LOCA requirements. I.t.was addition, ally- ~ . assumed that 25% o.f 'the EPSI inflow spills ouc through the. break. g "he ficu capacit'y requirements for the HPSI and E W pud:ps are proportional io values of decay. heat. Assumption (3)', therefore, results in a proper-tionate increas'e in "tihese require 5ents. The EPSI pump capac3.ty assumed 's shown in Figure 4. The EN capacity was_ assumed to be 875 gym (minimum). i Assu=p' tion (4) resulted in the folicwing setpoint and delay assumptions: a) Reactor scram occurs upon a low pressurizer pressure (L??) indication of '1728 psia (minimum). Upon receipt of the L?? signal there is a 0.9 second delay before the control re. ds . begin =otien folicwed by a 3.5 second interval to fully Insert the rods. b) SIAS occurs upon a pressuri:er pressure indication of ~ -(._ 1550 psia (minimum). The SIAS automatically starts the emergency diesel generators which provide p'ower to the HPSI pu.mps and.the E W pe=ps. The total time from receipt ~ of an SIAS to the time t? e EPSI pumps provide flow is 30 ~ _ seconds-(maximum). The total ti:ne delay from SIAS until EW reaches the steam generators is 45 seconds (maximum). References 1. Combustion Engineering, Inc., Standard Safety Analysis Report (CESSAR), Docket No. SIN-50-470, Amendment No. 31, Section 6.3.3.3. 2. D. V. Craf to D. R. Pattersen, TI-CE-117, subject: " Meeting s Minutes of 5/27 and 5/23 in Windscr." 3. Acceptance Criteria for Emergency Core Cooling Systems for Light-k'ater-Co' led Nuclear Power Reacters, Federal Ker,ister, Vol. 39, No. 3, Friday, January 4,1974. .i _.,/c;c e~ qq, 120(n /._ 1 /
4- ....t-,...r.... . _.a...n.. r.r _,. w.. ,..*,.,,.*...,,.,v. .ra... t.w s :..... l /,. 1.* : .r . l... e,. d. l. t g .l t /., t .e - i g ( * *:".*.!. ..I.".*
l. ' *
~""* - *"..... " * ' /. g. ,/ g...u,.~ ~ ~. - ~. * * *.,,.**['""***""""****** .e. i s 3 !.... g..... l. .~. ..s....._..._. ...I.......... -.....!.. ) ...g. .... l f ...c..!.m _ ..._.._...i..... s,. ..g........... t ...l !.._m . e.... 8 ....... - [. 1. . I......_1... .................._...I....!....._.. . l.. c...+........... r. (. _ J. a l..... ....g._...g. .s ....g..... l..... .e 1..........l..... .l. l.. -.f 1.. .g J.. 4........ 3. _ l.. --...-.f.... L. L.. 1.. -....... ...., 3 l.. ..t _ l..
~~1..~~
~~........._........1_.. 1.... ... _... 2 _...- _.-._.,......m.f...- ......a.3._......... ..1. ]'. l....l.. ..,.1~~
~~1..~~
1...-.....!.-,.. __.....,..I .. ~.. .1 .l.. .i ...1...._ . -.........<. t.-... .1 ...J.......l..... .3.- 4.. . ~. ...>..l.~.. ....m...-... I. ............. f. ...........L..............._..l.. .l.... ..l,....... _...._.v..l.>.. . ~...... _ _. ........:....-.1 ..4. _1..... f _3....--- ......,_~.t4... . O. ._l,. .......l..l....._.... ..,.l.._...... _... [.. ..I.... . _..... 3. s. ..3.... = N. .l_... - l. 4 ....,..,......l......u.......- ..1...._1_........._...... i. -... .<.d....... .4... ._...f._.. s.....,_..._ ......l....... .t. .n .....J.. ..m.__..--.~.4.._.._..._._..l._-............p.._-.. .._....1_.................;....f... E. ,t. .~ ..........._.... 3.. ,,. -.... I f... ._1.._........_... .._......l,.._......4.. .6 _... ,. _ _.. 1,..... .., >, c,.,.s ..m .(n...q t., _... g ...l. 1,.... ,a ..-.....J. . N. . s. ....--..L....... ..'._1.._.. ......_..t......\\......~....... I. w. . _.......... l.a.. !. _.,.. ...)_.a._..T............._..... .i. ... _..t....,> _... -") ~ ._-.1.... .,..,.l_.... w 1......... ...g.._..4...... ..~. .,al f _ _ 1.....I_1-. .g .s ...l....... ....J. _ w .1 L........._..1 ..".N. ..r......._....l._......,
~~...._,.g..~~
~~. I ~~!. W h., .. _. _.. -. _.. ~ -. _. _. .-_). 2 .m . _ a. !, .m ..=, ...I N,. ..j... y...~~
~~4.. J W~~
c .,.F,. . I.._.. ..g.. ...... - =... _... _. e4 m ....g g ..) _..i. ..._.1.._ w . s. ..a.. ......O........,. ...\\- t_. .d ....,.._..._...,,,..,...._....8., 4 . ( .............T, 6 D, >.._f..... _...,. m ..(,, W Q......... s.w, ....t _._...J. l. y. m u ........_J..._,,...1,~_..t_... .e .a,...... 1.. sQ ,.....J. .s' W j\\; . l,.._..... _. _..........._! _-._-1.., H ......._.4*._.._..._ l...-._. ............t.. s 1.. .....................p. De .m ............:-.!...e -4~ p: =. ( O .m ......,-.6....J_.._.....!...,...(. i _... _.... ~- ..._....I 4...,. ._.l..!...,..... p .s. s i. . t ._.1.,_.._._..........[._.._...........,.......... ,...t........ _....I ....... _.....-.......f..4.-..,.
1...

9......
~~.---.l ....t ...,.... 1.... i ._3,.._..J......g._.. ....,. _.......,.J.... ...t... ....J.~~
~~7...~~
~~....l_. .... -....$....._._._.g ._.....1.. .. !. "a _.1... l..._... _. .s ...n..,.. -..1._...-_. e ...t....!......_..........._. .. I. 1 ..._........_1._...... .a........ 1,. _~~
~~7.._.. ~.. I.~~
. ~: _ 3. _. _..... -....._ 3.,.... .. _......._.1..<.. ...l......._. ...._.*t..._.~. t.. .... { .,l_........,... .._.......1.......!. ,i. ._.._.__..1..._...._..,.._._.._._.._._........ ...... _. _.........J..... .. 3_ ....-1..<........ .c l. ...s ... ! i........... _. _ _.... -... ._.!._.._-1.......___..._._..,................... .!..........1_. ......... _....f ........_.._f_._L..._.._[*. l.
~~1.._.....~~
..J. .,../... _. .. _....j..,._:.... ...l._,...... ..._.T..... r s ...,.I._... .........,./...... .....Il.\\. ...._....!..........j...- _._..l.<.. _........._...........1......... -...... . _....l. _. \\w... ..!.... _.1- _..l_............ _.... _.._..... .._r%..._...._...--... 1... _f. ......1......._... .m L. .= 1,. ....i.__.._ _ ...... 1. ..:.t.~__........_. ....._.l........N.- - _. _....
~~1....~~
r.. ..4... L. N. t. 1._.. = ............. _......._..f_. ...l.._,.,.. .l _.. ~ .....) a f. .=. .....L._.... .a ..l. .I M l. ..g..........t._...... _ l-n...l. .i. .1... . Q....- ... -.. - -... ~ ..i......... .g ....... N, _...6; l _ . _........_.__.1 ....l..... ..,_.h.. ,-.._......\\... - Q _........._.....,.. . J.. s. ..,...,). ....v. .. ru... _. . l..r _... g g. 1.. . I,g. -. _. --4...... b.s...,_ ts......l,. g. i ,g g -.., \\.r ... I.. l _.- [.. .( ...1.~.,I. .g..,....f.. .. 1.. ..I .............. 1 ...t...t.*,,,,..,.!..,.,,r..,.I.,,.,,,,,,..... _.g..._.._....... ,j,.... 8 7.f ....... 1 _.t.- /... t,. . /,. _y _... .,... _.~. 7. .g. 4..,,, .l.. t. _ .......j._..... .) .e
~~1.. 1..~~
~~. _ = 1 f..1~~
~~1. _...l.-.-.~~
~~f._.....~~
~~4..:........__~~
s. .._._.............l.. ....I. ._..._f. . 4 .s.. (. _. _.l .t...I. .l.-_....I.. t... . r-. ,..e. ..I ..r.... ......l.. . m. e, ,..l.-. r: 3 ..l. .g.,... so s.. P00R DEMb m
/.,,,,,. .. a -..-.7. -. 5 ...,. 3.-.. _ -. -,.....j i I y .t / ..l ..i .f .I. e i f. .I e + 4. g. s t 1....!.. e......... e .!.,... I e.,d. t ..... i... ....t ,......I.,....l.,. l...s. . l.. ...I... e. ..I. (....._...
~~e..~~
~~.. 4. 1 8 Ie s.1 e p .I ...8.l. . t l... 1. ...L ....t_~~
~~e.....~~
~~..... L. - . e.. .l.......,....... . 3.- .,s. .i... ........... L.. 8.. -,..l....,. ,.1... 3... ..ed............ l..-. J.. .g ......J.... e t,,._ ...,. L, l -..... - -,.. ...............I i.~~
~~3....~~
c. 1,. .j....-. .31 l.... t .t...... .l... \\.J ..f. 4... l .=. ").. .....=...... 1 . J.. ..,. 8.. l.. .., =.....-. - ...f... .I...... f............. s.%. ,_..l 1 1 .. r... l. f......... .. t. .........l...... s. ...l.... . 2....~.1...- ...,.<...._........__..............o,... -......... -.... .._.a ...c..-..1.. ..l... _...... _. ...a.... .,1 ..f .l... 1.-. -J... ..1.........,..._-...l.-. .... -... 3..... _................l. .. 1.... j .m,.. ....--.I... ....,..........6.. .. \\,). ;., p......... o .3. .l .1 .-0............ Q...l .t.. ..m.m. 4 .g,_ , e. e.1... e.- il.i... .."."1_...(. g. m .u.. ge s.- w.- s. .m. mm.. ....mmmm.....mm_ ..8 f.. .y ....g....... - .l....................... ... 2. --. 1. ..... -.... ~. ..)... ........ '.., ::b..8. ..T*..~ q.........$.....l............... . m m.. e n.. l...h_. r...... 4- .. 8. _. .m m. .. l..... e... =;. e-e np m. ...I. #....e.,.... ). !..u 1.e.ms 4 ..s a. .!...)., ...l_.......l.,._. l. ...l.g. _.....! .'3*..( . f. l. g. .. :J. s._ _. I.-_. I.. g .. ~. e .l.._>_......,. .g ............C...d.*= ..I .\\ ..I ......_...._.6 s.... . 3 .(. ..\\ .. l......4..... -...... p_..4.. ..... l . e.- t I.s f* m. p... _..J .a......s......i ...f*.......t. l*.e....1....6 .....e...... t. ...-.1..._........... .,.......l__._.,_J_.... ... 1,.1 <.._4 . = ~..................... -. .... 4... .g l.4.....a.d-.... ,._ _._ i..... -......... 1... ..J. ...L......,... h L...~....._....._ _....._... _.. _.....,.......,...... . _.......;-.l.._ 4.... ., J.. l. l........... ;_- 1g r.......l........_3.... ,l. ...I..._........... :..... 6.. .... _........_.1..... .. 1, ..,.,...l m l. ..-..} ._.,...--1..,.......... m .,..1.._.._............ . J.. \\.. ......_..._%,- i.. l_.- v 1 ........4,.>... lr ..)... N ,f" g ....... ~...... ~.. - _. % 7\\, .. ~. _,... _..., _.. .c c., .w.....s....._"1...._......, l.. g... i.- -.. ['"..q.._...._........ g14..._
~~y.......~~
............t.....~. ...4..n.... .r.- .g g '3........_.,....... ....4... . ~. d ,.........._.4. ........1.... g.< p. .vj . l.. 't............-..-l,. 1.._......... ...V,.. ... _. l W. la (.. .=. .......1......,4..._,...,,.- ....-.e-.-~ .....m........ f.A. >= w _._.u.y-J._...,.. .,....,....... l.. -..... p y. ,.. 4 ..).. m.c........ -.. _ .s ...l....., yy .T.. .........-..,.....1.. ....t..1....., 1.... .....]...<..._!~...,.....
~~a... 6............. i,......-.... --....,......~~
.......l...l..... ... !.. 1.. g .w.. _.i g. ... _...t... .g......m..... s .y. p,. 1 g.... H. _....-... gg.. -._-l. . _..... =.. .t...1.-... 1 F ... 1. *l... 1.. g.... ....1 -..g 4.. ,,. 1 ............, _ _.... _.....l..... .J.....,.[........J.. ] ......__....l...<.... -....l... f........-..-.,.. ../.. .g .l....... ...l_...._,... ..,s.. 1 ). .._ G.... g --..._...!...l.. .............. e f q .g .e ...a... .p. p.. ... ( ....,/. e.. 1 .....l.....,- 4..... l... ......... _..,. _.........t 3.. .........s. 1... .s ..-...........l._...._.. -.. < ) ...,,.. e.,..-..........,. _.... .c 6 .e,......,...... .....l..... ..4..._....... ""L _.s .e i._._.....(~.~...l......s........%....... ............lj...J...._ ....,e.... ..o .e.... .......J....... ....<.f...*_.....N....._ a. .A f. l. .. V. t .l .f. y . l.. .-...........t...,........ .......g........... .l .p #. ..I __... ~. . 11 ..l... ..._.f ,........._.. t. I.. _ 1...J..... ....l... .l..~.......... .l ..._........{./.. .-...,....,.l.. ., 9, y.-.-.-. .,1.. . =........ ....{. ...i .1....e-. .......1...T......_../..
~~l..... _...~~
~~l, .......f . l.........fl... .l..~~
~~s...~~
~~a..,.. r.".~~
~~.i..~~
.g. ..l .s.. ...._1.....,,../. 1. ....1 ..s. .g.-.. - - .)._ ....-.....*l...-.. 4. .....l./.. l... .,.4 ..._-.g................... -.w.... .ve .4 ..g. -.. 3 ..--..._q..~- ..i .g.,,........ ,.. ;..... _.....,7.,... ,.w.. 1 ...g... .j ...Q...l . (%,. .l... 9 .........,.1. }... l. ._ m^. .e. ..e. .I i+!. .s.-..1........ 4 .J_ .-.-.6 D. 1 .. -...----.9- \\, ,. I 3.. .. ("J, .] 3,, g J.. . ;... s. ..... s
~~3..l.~~
g m.- .N. l. g . -.'i. [ l. l. i i.. t .......... 1 . i.... ..J/t...'."b...>.,../.... .1 ...... l.. s .).. a....-.4 e. 3 /*,,. ..'".L._ /. /"... j... .o..... i. ..l ......~...;...........).,i.8.... . =. -.. .s. .i. e..
~~. ~ ~ ~... - --.~~
~~4 ,.....l. ....1.. _:. t .p.....l.....,...,...t :... d .,3 ..a.. . I. e.. _3 .... - -.. c. i.~~
~~1..~~
~~I....._, .... l .. l, ....-...l.. . p. .,q I.-.. .l.. .l-g. l. . '.t. 1-g.~~
~~...g.~~
m
%. ^.. s 4..,....s. .,,...g .... m.4,. \\. *. 1"' b e % ). 1 ..I* 3 e 4 i 4., f. yT s. J'..
~~s...~~
%.} ..e ,J. .h ,j .,I. A. L. .s w .s. d, g.g. .a ..8- .i .g. g.. . I.. /.- ... 1..:. ,a s. .J. .e. ...g. g g.- s.. ,. I.. ~.e 6 I,......... "... g t .g. ,l .-.g. .e E.. l .. - -... -....J ...c. e e
~~g.,..~~
~~,... I. g... 3 l... ..1... ..s.... g ...e........ l .s..~~
~~s..e g~~
.... } ..,. a.. l. <...g.. .g .>= . e, a g. ...s .....e,., yo ...g.. - -........ = .......4.,. c a co \\.. t.- 4. c *** U - *^... i*.\\.. =.. .1. -,.,..,.$...,s... .a. 4- _.l...,...l.,,... ,.... 1.s... w ..-.I....=.~. ..l... n.;.a e',. E ...., 1. u .. l.. 4....l . g.....::..,.1.>...l.......,....., J.. 4.._. ....... -.. ~.. .g. ..t..=.. 3
~~- g th0 u r3 w~~
..,e.e.i.......... . l......... - - ..,,4 gg e . _..\\. l 1..........l 4. .,2. ......f....i,1.... g,4 c x. ,. a.,,. l.... 4 m 6 t/3 . g 4, .. m ... J..... l. - e. .,...,[..l... .(g. g g g p gM ..a .e ..g... . g ('*. .-.i .,4
~~3 c,~~
..3 ... = - p... -... 3 ._. s g. ... \\. C. O..o .g( g3.. .o..... ,....i...... ........l.......l.... .......s y ..-} l J... ,.. -......g.u ...\\. m. Sa C ...[~. ./1. =......- c a ~... e.,. 4. l.......=.._,... [ p + e o .........C. .a. l.. ..!...I ........j_ .s ,4 c ~ ... (.. L.,.. ..g p, 6 g. ..7......._ .._....C.. ....l. 4 ...l... =.s. g g y a f. ....?. . g .g g g ... _. l 3,._. )...... .. J.. o o e.. c .....,l... -... l...... ...1...,,-...... . mw a y,,.e .C A m, s,2. ~, c ....s.....; '... /.,e.... a. .g. .e. el . (%. cav .a_...__ mU be ...........1...,1.,.t........ <. T. .....a.... ,t .a
~~l3 s o c.o~~
~~...s u ; u, ... 1.... l .. s... e 4 .3 co E C %v ....1 .......i..._~ ..r. ....J .s. a 3 E ~ s (, . n.~~
~~4.......... _~~
~~~4............ >n oU s ...e o a C,*, v .4 ._..I ~...... g.... g u. . u p.a c ..*..l~~
d
..l..4............,......_..-.3.e p.l..... V,') c g3 y2 W ..a..1...!........,._...I__.4,.. ~..W.. .c o.3 d c a .[ s...$, H "O U3 - J V ..4 g D. c. ..........l....J_...s. g c .g -.. _.g e.. U P t:f u. w, u ..1......_..,_.._._,..__......i.. . T 5..,._.t.. !._.. - e, .................j-... _. C, L H u.s .l . \\s .,.-""4..._..s-g. g:. m .__..._..J,...._,....._.. p .u w N ........s....,......g.... _.. s .....I . s. 6._._.:. C. y, U"J s.. 6 i y.. ..... -......-..\\. g g,; .,,g .l..__._ .l N . -............_).. c.c v. + -.I_. s.._.. 1..... . :. t.... N. .. _. 3. ...n..... .-.,,,4
E.
~~H 3 _ a e t.+.i.... -.l_.- /*- C.~~
~~D w~~
~~. -~... -.... ..e ..%..,..._.fc..- .C C; es~~
~~l..,~~
~~).. ...._._..}.,...I........, g ,\\ .. 1.., '7.".. 4 I.1. _ !* _...... L... -_.._...J..~~
~~p...~~
4 ... ~... . V." .c 1.............. w .{:.,._... p_ g4 g gg y ..............l.._...__- - -....,.. _ ..... L.3 -.. _.../....... s-A '\\ .j .i d. g.1 l.._ .s ..... 1.... N..... 1 ....s .rd .q .... w,......- p c y s. C .c. ....7.<.........!.._ ....s.g.>.. . %..,%.!,9q.J ....,a.. v v C c ._J~...,r...... g y C,. R ....... _...,.... J...._.._.!........_..
~~s..~~
~~.. _....J...........%... - -....,,,..~~
~~1..~~
~~.l _.. w ga .,.... ___c. w g m .s._.. , sr. .p _ t~~
~~n..-~~
......._.3..a ...........s...,.... .d .s ._..... _... 1 _... ...t .... y. _......... n J. .._2.. ..N 1 ...*%..,,..........t..._... _..... ,i . _...... 1.,._.... .t............ .i.. 6. ...4. _.f...... .-._..f.. l........ ... l.. O t_ ..i. t,y ....J.._.....,... _._.._...........l... -a 4 _..T ...._T........ 4..... _.. _.v.. ..i 6. ,a ..+ .... *A..... .-........ _.._......-.......l. _,..../.. i ...r ,...._.b._ . _... _.l.. t ._. - /.. f. c - _ m... n ........e..,..,p.. s.. t....,...1._... ... _.. _.. _. _..,.. _.... -.,_1.. .X..._..n_,. ........ _..........t.._.._. .n....,.
~~1..~~
~~........s _.s. i.. ....s.. p. ......l._._...,. .s TN 1. 6.. 1. l.......-__.f.......,, _. _-.. _..-..... _..... l. ..l . r** .l..... s.. ...1 ,.J...~~
~~2..~~
S.. ..-j........._J.....1......l s..... _.)... .f................... a.-................_-.l......... .{.. i._.. 7._._. .,..4... .\\.j:. ./....t......_...... /*.s. . '.s.p.__. 1,. _.../.",'.g..... 1.......,.. ...=.... ..N.,...../...- ,s .I. /...._... _.....l.........._- t., a. ..s ...t... y *...._._ a. ..t. .a _l. /.. l . %nf.,e l [..,....
~~t. _ _g.=..!...../.._.......~~
.,.g..,........ q-i g ..,.....J L.._..i=...... c 1 .... =.. ...p. i ,.. _. f a s..e. _=. .._.l....... .... I .._J...._...7._..!._. s..... a,...t...,. .-..............p t ,t i.-._......_.. I. , -... -...l. t s= <... -+. i ..J...- ~ _- A,>_%.-.....,.,., .e .i........ ...l....- s ..g.. i.... nI. 1 -..l........ I.
~~......I..-.. -....~~
f_. ,._.i.... e ...I ..1*.. .s. v g... a. -..... . !... s/"*, _._,,......... .1. g. g. ..r .. t t, v.1 , ti 1 ...... Q. .g. t 1. . _.. Q._. g, j.. s...N.,.. g.. g ..,....h .--._._1... .T. .. d,.. ..e...- s .....J. ..I ..l. .-.g. ..: - : g.= _....;..l ~==f =,,.. r
4
~~...",,'.,,,..e==.k_*.y 7*.j .y =. - _ _._ .1~~
* ' * ~ ~ -
~~r...._. y. =. y"e._..,_,.fU s g / *s' \\ 's~~
~~Qs.,;*,.j..f., *)~~
/~ l .g ~. * * =* m q I) J=l 21.)b 'q / / L, J
.~ FIGPI. 4 fp i g = 4 .W. tot 80 6....
~~J..,..~~
F. PSI Pl!!IP CAPACITY. ..s... .r. .F.ini:.u:i Capacity f. o'r One Pub 2 .._t. .. _ l.._ n....... ...._.1.... .. =,..... ...t... .t w.. i.._ i.... .i.... ..s. ..i. . -.........._......s,._................... ....i......... _.... ........1... ..i-..... _.. .......~.. _.. _. _3, ._..t......._._.< .......-.i....... r.. 1.
~~r...~~
.. _.........t.._.. =..... _ ...i. . _._ _.._........,.. s .._J_....~...L_-...._.... . _J... =._.t... _ _.. =............ _..r _.._..... _. _... .1..............,....,.. .. ~... ..... _...._ 4.....,........._......_..:.. _... -1._._....... ...r._._.__.. __.4__ .._t._..... 3_,..... _.. _. _................ _._.i......._. .._...u...._.,.._..._-....,._.i t.... .i..._..=...i........._.._._...._......, ..-...l.,_. ..1._.... t.._.._..._. ~. .t._...__._.... _. _ _.. _. T.1ou o ore. ssur::es ...._.._..._..._..._....._y. .e.w,.,, a e.
~~2. r ou.~~
rea a s .. _. _......s. r. .:t. _. _ _. = ...t ..,_.a__.:............._...__--...,_._..... _...........,._..J._.. ..t._._._.-....,._..,_ ._...._.i._.___ ....._n_._......_........._.. ._= ... -.....r..._,. .._.._.1..........m.._... ..........,_.. _..i _.... _..... _,..... _...... _...L_......._ .m ._ s ..._._l._...._........... .= ........ _..........._.._ i..... _. .s. _.. :.......... _.... 4_.__.._.__..,_._.a_..__ .....__.t.._._ ...... =. _ _J. ___._-_ _._..... ._t....___._.1................s .,....._.._.1........- i_.... ..i. ... _....... =.......:. 4.. r. ...-.......i... .....i. i..... s. .i_... _.. _i......_...... . _.. ~ .s._....-. ..... ~. - i..._ _.r.. _..t. ._..i....... _. _ _. _. - l .i i. -.. _....__ _ ;.t._... ..._._...s_...
~~t..~~
i. ..i. =.. _. . = _... i i .l. e .s. 1.,.., ...s. ../..>. .........,9 ,.......t. E. .1- _. \\. 1 ...l . n... e v..' e c.: C.,,J_.,__,.G.:. L, :...: !.. > t.A~t. O [b ' /d L _. O,
ENCLOSu22 8 W t t DECAY ?iEAT RE!* OVAL-DURING A VERY SMALL g3_h3K I.CCA FOR A_3DU 20}- 5_EL-33g g PLY PWR s C. Michelson January, 1378
~~SUMMARY~~
This report gives an account of some initial considerations o'f a class of very small creak LOCA's (probably 5 0. 05 f t2) for a 3DW 205-Fuel-Assembly PWR which may have an associated decay heat _ t removal problem. The results indicate that one or more impedinents to decay heat removal appear to exist which need to a be better understood if proper operato'r response and adecuate mitigation are to be assured. Of particular concern is the acceptability of intermittent natural circulation following the postulated LCCA, and system repressuriration following the loss Also of concern is the possibility of of nat' ural circulation. break isolation by operator action resulting in reeressurization and slug or two-phase flow through a presurizer safety valve. These uncertainties may reflect on the adequacy of crocosed emergency operating procedures and operator training for a very 7 small break LOCA. __yj...n :. Ca n ) Y
~~n i n.. n wl cw n,y. i g~~
3
~~a. d e~~
v 7 q 06 62_0\\ 5 1269 '27
I ~ CONTENTS
1. 0 II;TRODUCTION 2.0 LOCA CHARACTERISTICS 2.1 Mass Flow Rate Through 3reak 2.2 Decay Heat Renoved Through 3:eak 2.3 Reactor Vessel Top Plenum Drain Time 2.4 Steam Generator Drain Time

2. 5 Steam Generator Refill Time

3. 0 MODES OF POST-LOCA DECAY HEAT REMOVAL 3.1 Natural circulation 3.2 Transition fiom Natural Circulation to Pool Soiling

3. 3 Pool Boiling 3.4 Transi' tion from Pool Boiling to Natural Circulation 3.5 Shutdown Cooling 4.0 WORST CASE LOCA CONSIDERTAIONS 4.1 Discharge Coefficient and 3re'ah Location 4.2 Decay Hedt Removal

4. 3 Level Turnaround and Energy Iquilibrium 4.4 NSSS Vendor Calculations 4.5 3reak Isolation and Pung Shutoff Effects 4.6 Pressurirer Level Indication
~~5.0 CONCLUSION~~
S TABLE FIGURES 3 e fi o e .*v. T . ~...
t.
~~1. 0 ISTRCDUCTION There appears to be a class of very small break LOCA's (probably S 0 0.05 ft2) for a BSW 205-Fuel-Assembly PWR which may~~
~ have an associated decay heat renoval problen. For this discussion, a very small break LOCA is one for which the steam generator must remove',a significant portion of the decay heat during the initial phase of blowdown; otherwise, reactor coolant system repressurization occurs since the break is too small to facilitate the transport of all decay heat to the environs. For this class of IOCA's, depressurization rates are relatively slow Iwhen ccrpared to these normally analyzed as small breaks) and thus may seriously limit the makeup available from the high pressure injection pumps. An ongoing qualitative consideration j of this problem now predicts the. development of one or more impediments to decay heat re=cval during a 'very small break LOCA. This has become a concern that needs to be understood. ~ The physical arrangement of. the reactor coolant system for a ~ . ~ ~ typical 205-Tuel-Assembly plant such as the.TVA Bellefonte . Nuclear Plant is shown in Figure 1. Plant elevations corresponding to various points in the reactor coolant system are indicated. Decay heat removal considerations during the post-LOCA period are based on the usual ECCS rules such as loss of offsite power, minimum ccre cooling (one train) response, and no sho r t-te r.m. recuired operator actions. e O \\?69 L-
~~N.mam~~
., u 2.0 LOCA CHARACTERISTICS g A few elementary calculations can be helpful in develeping a better understanding of the various modes of post-LOCA decay heat removal and the role which steam generators must play during a very small break LOCA; of particular interest is the mass flow rate through a costulated break, its capability to remove decay and the makeup rate to the reactor coolant system required
~~heat, Also of interest is the time to co..pensate for any lost mass.~~
s e required to drain the reactor vessel top plenum and steam generator tubes during a transition to. pool boiling, and the minimum. time required to refill the steam generators if a level turnaround occurs. For nost calculations it is a,ssumed. that a quasi-steady-state. 4 condition exists with the reactor coolant system at 1270 psia (574.coF)' and' the s[econdary. s1de of the steam generators relieving steam to atmosphere _through a safety valve. Where ^ applicab'le, iE is assumed that a sufficient temperature . differential exists across the" steam generator tubes to transfer. .. ~ 4. all decay heat not. removed by.the break. The decay hea,t is, based on the ANS decay heat curvel using a 20 percent margin. The reactor power is 3572 Mwt. The fluid upstream of the break The flow areas is assumed' to be saturated water or stream. (potential single-ended flow break areas) corresponding ro a nunber of nominal pipe sires of interest are listed in Table 1. ?0DR01BlNAL i26"' '30 1 Proposed American Nuclear Society Standards " Decay --Ener:y Release Rates Following Shutdown of Uranium _,
The pipe schedules indicated are typical for the reactor coolant pressure boundary. It should be recognized that calculations included in this sectf.on are based on general considerations of energy a'nd mass cons ( vation under ideal fixed conditions. Fine structure ef f ects ' have been ign'ored to -f acilitate simple hand calculations. HoJaver, the re,sults should still be useful for general guidance if the simplifying assumptions and calculational limitations are appreciated. Detailed transient calculations based en appropriate system heat transfer and fluid flow models and' core thermal-hydraulic models are required to put these cencepts on a firm basis. / 2.1 Mass Qgw_ Fate Throuch 3reak .s T! e mas's flow rate through a break assuming saturated water or steam.upstreap of th.e break i.s sho.wn in Figure 2e. The saturated-water and'sbeam~ curves are based onJ:oody's2 Figure 1 ^ ~h.m for. stacnstica pressures of__ 1270 psia and.2500 psia with. < ~_. ;. -.u, m. _.2 Moody discharge saturatei liquid a'nd_ vapor entrance properties. coefficients (C3 = _ actual flow / Moody calculated flow) of 0.6 and ... a.
~~7.... _..~~
,;~ :,. i.,... y. 4.......... g"_ . 1.0 were " elected for. calculating the saturated water case. The actual coefficient might be sc.ewhere between as determined by such co:isideratiens as the break Senf'iguration and whether'it is in a large or sea.1 pipe. The discharge coefficient.for steam is assu..ed to be 1.0. P00RORSNAL ,g ,20< 3, 1 2F. J. M:ody, ":.:aximum Flow 3 ate of a singie component, Two-Phase Mixture," Journa_1 of Eaat Transfer, Transactions of the ;. erican society of Mechanic.ai Encineers 87u No. 1, n t
~~'abruarv. 1955..~~
4 The makeup rate available to the reactor coolant system to through the postulated break is shown in compensate for mass lost Figure 2 as that available from one high pressure injection (HPI) pump at the indicated system conditicas. The water available for makeup is assumed to be at 700 F. Removkd Throuch Break 2.2 Decav Meat The decay heat which is removed by mass flow through a postulated break at 1270 psia (assuming saturated water or steam upstream of s the break) is shown in Figure 3. The heat removed is based on the mass flow rate given in Figure 2 and a stagnation enthalpy corresponding. to the designated upstre'am condition, i.e., saturated water or steam. A minimum value for Cp (0.6) was selected to yield a conservative (minimum) value for the heat = a The decay heat removed is shown as b percent of total removed. decay heat generated',a,t the indica.ted time following the break. - t I' It should be noted that saturated' steam l upstream of the ~ ~..;:.... .a r -.. :..:-r p'ostulated ' break will" remove a little larger percentage of the ^
s
~'.L. z- -a.1:3 ~ ' - . decay *F. eat than saturated water. This will not be the case for ~ ' ,4 =w p with saturated water upstream.' The larger - 1arger values ~of C3 ~~ mass flow rate for water.can more than compensate for the t difference in saturation enthalpy at the indicated upstream >= " ~ "~ ~ P00R B H M The time after a break before all decay heat can be removed ~~' through the creak (with saturate $ upstream conditions) is indicated in Figure 4. This is the time required for the break to be in energy ecuilibrium with the decay heat. The effect of I269 '32
values fcr uater is higher pressure and a range of possible CD also shown.. 2.3 Peactor vessel Too Plenum Orain Time The time required to drain the reactor vessel top plenum down to The drain the top of the hot leg pipes.is shown in Figure 5. time is assumed to start after reactor trip. Pressuri er level is assumed to remain at the le el achieced immediately after trip. The pressure is assumed to be a constant 1270 psia. In i reality, the pressurizer pressure _will be somewhat higher during ~ a portion of the drain time thereby., reducing the drain time indicated. Although some additional. pressurizer draining may occur, it is most likely that_a refilling will commence shortly af ter, the reactor vessel stear. bubble starts to form and become. /_ -. ~. controlling - Therefore, the drain time' giyen in Figure 5 is - r-thourght to' be"a good estimate of thepaximum time _ tliat natural m circulation can be custained for.a given break size af ter reacto'r c. .c g .ujffT. .g .... y ; y
~~s:,~~
~~- gy$pf M,~~
~~p 1..,. :.. i-p a m,; c r.,.~~
~~. e '. -. 5'. a.. .-.. i-.; A.5.. jf._n %l. ab,b'. :J... L,9 f.. 4...: '. --- m. ~ ~, u. ,- ~~~
~~2. 4 ' Stea m Gene rator Dra in Time 'W.'. z, (L.:-~~
-e S' -7 .u.: .... f .w. 4.3.-- m g.e..j.... ,.;....r.,..,_..y.. .c -~... - - ~.. The: time required to orain the: steam.--. generator inlet piping, ......,z... and tubes down to the secondary side water level is shown plenum,. -t- : in Figure 61 "This drain time is calculated to start when natural circulatio~n is assumed to be lost indefinitely, i.e., wh en the water level at the top of the steam generator drops to below the inside dianeter of the U-bend high point and restoration of leve'. is not expected. The crain rate is assuned to be the mass flow rate through the postulated treak (Figure 2). System makeup is from one high _ pressure injectica (HPI) pump delivering a constan: - _ h..D'.n,.._.').. ) n
e the indicated system, conditions upstream of the mass flow at .The secondary side water level is assumed to be break. increasin: at a rate of 1.75 f t/ min which is attributed to a 600 The initial secondary side water gp:- auxiliary f eedwater flow. level is assumed to be 26 ft. above the bottom tube sheet when the steam generator drain is started. The effect of upstream pressure and initial secondary side water An initial level on steam generator drain time is a 1so shown. secondary side level of 6 ft. is the ncrmal auxiliary feedwater s control, point until an engineered safety features actuation. sign $1 (F.SFAS) is initiated at 1600 psia. It is likely that the at the steam gere f ator level will be in the range of 6 to 26 f t. time natu: al circulation is lost. The eff ect' of an initial level of 48.5 ft (top of SG shroud) is included., This is an upper r I-limit f'or cractical..; con,.sidera. tion since the overflos enters the- '.fhe effect of 2500 psia'. reactor coolant. ~ ~ ra in' s.te am 13.n, es.. a g. (set:' point'.of-pressurirer safety valvps). is included for pressure q. . y*;~ Yefe:e'nce. F,.'~~ E~*h5. Y ~~ $ 3 @.'*4 ~. -Lu. "; ~ ~ '~ )_ . +. - ^.. :.:: :,,:.;.2;.:: u..'.7my- . pyr..;. _. n Y. = %.3 .~. l p :_q ". J ~.L-. +.;-..: c.,,"a. m c;. 5.e-p g.e .;,.w.-a.a .... g.,:. - n --.. ^ -'2
~~n.,,::.. i c;. as :-~~
~~.vgW ~ll Tim, e' 2. -.. ~ W~~
~~2. 5 steam c enerator-Refi~~
... ~ 0 . -r.. ~. . v..5.:, ; 4.~.. z:.~ 4:w.v..,- ..r y. --r _r'g~~Q^. : y,*:,7.*j(!Y.* rj ?::'- y ill tine is the " time ~ requir ed to ref ill - ~-J'.' s.A K The steam generato (ref ~ the inlet pip'e and plenum and s, team generator tubes if a level ,7 turn'around should occur when the primary side water level first reaches the secondary side water level. Typical times are shown ~ ~ in 7igure 7 for saturated water at 1270 psia upstream of the The inirial steam generator level is that level which break. .s. existed when the steam generator drain started, i.e., when natural circulation was lost. It is likely that the initial )20/ n ') ! in . t ..,.,s.
4 The steam generator level will be in the range of 6 to 26 ft. F curves all start at 12 minutes because this is the minimum time s" required to refill the inlet pipe and plenum a'nd that portion of the steam generator tubes which is above the shroud.
~~3. O MODES OF POST-LOCA DECAY JiEAT REMOVAL i~~
Af ter the loss of offsite power and reactor coolant pump coastdown, the two basic modes of post.OCA decay heat removal from the reactor core for very small breaks are natural circulation' and' pool boiling. Decay heat is removed from the system by single or.two phase bloado'wn through .e...y... c. y.. reactor coolant ~ the post'ulatec break and by a release of s'.eam on the secondary --e ~ side of the steam generators. Any decay hea lost to the ..s ~ ens-i.ro.ns through thermal insulation is small by comparison and is ~.'. -:. 7, ..;. (.1. y.,. j.,. u.;,..reak si.ze is..a.s.su.ed to be sufficiently .:.f. th e b... 'I ~ neele.cted. ~: largeE %...n..w...mmoi e.of ~ the foll'o gi.g ' phases, of.operat, ion ma .. ~... .....,. f <..:,. ..two.ori T . +.,:..n.:..- u.r..;; q
~~m.x.;.-=...+... : ;~~
.w ex. =a.r_1.en c ed, - e e.,..-s. c. s n-a ... q. g. 3,fq-.., t .,r- ..y . -w 3,,. l1 .., +.r,.. u.ss...,,. : 2 ; 1.,.... .... _w - .: =.. :;.. .gr.3 p...:c..m:::p -:c - '.. g.,..... - ?;;.:. w_ y;.. )[g. ..s. M. + g ..a t. Natu ral circulation '
~~y.. :~~
~~j.,. D 3.1 c . +..... s.~~
~~,... zy.v. e. a..: r.~~
x .:e .r... c#:,v, 3..e e;.,. 2p .mm. ..... i t.. .. :.-r n. __,.-.... m. y< . c-. - -natural circulation starts. witl.i,;the pres suri:er still' controlling - .r..... .,.:. - c a r.....:. a ~.. _.. "~ svstem' pressure at'acproxir.ately 2250 esia. tiowever, without an. .~ , ~..,.... effective, heat iriput [other than the pressurizer r.etal) to .w. r. c., :... . 2 .._u, c:. pensate for heatf.rer.oved by flashing the pressurizer liquid, the pressurizer level and pressure decrease rapidly as the steam bubble expands to fill the veid created by fluid lost through the break exceed'ing liquid makeup capability {LCCA condi tion). could create Figure 2 indicates a break area exceeding 0.005 ft2 this initia5 confition at high pressure. J;n 13r
[ ' A significant system volumetric contraction and corresponding b' - i:er bubble expansion occurs when reactor trip is presst initiated ati 1945 psia. The bubble superheats to the pressurizer effective metal temperature. The bubble nay expand until superheated stream is voiding and condensing in the vertical hot leg pipe of the reactor coolant syste=. The engineered safety features actu.ation s'ignal (ESFAS) initiates at 1600 psia thereby. assuring maximum availability of one high pressure in-Jection (P.PI) pump wituout flow control, and inclation c the letdown system.- -. r. A new steam bubble forms at the highest ' temperature / lowest' . pressure' location.in the reactor coola'nt system when the pressurize'r pressure becomes l'ess than the vapor pressure of the .a w., .r '( - ' ' '... ' liquid-'phit'se Tt the new location.. Since there is no significant -
~~..,.,.,=..t.p:2e ay :g;.4 p.g...:...z.. :. y:. ;.. '~~
~~heat si.n.v..i:i'ih.e to't' 1'eg pipes between the reactor vessel' and -~ k x..a., >.. . m... . : s.,. n. . -. ^:. ..,-:'~. .p..m-...c.~ s w..~~
~~e..:~~
.t
n.
r 'iteam'ge'nir,atBrsahe7 highest _ temperature / loves t pressure.. .s. +:. +. 4 *.r.%4;": :'.l:.9.,. : X: -f. =;:.:.... k ~ . locaticn. 'could. be in the U-bend pipe. at the top of each steam ~.9..:.p,g.rc;.:a;;.y. r. ;. ::.,,.. ..c -: ,....w....e.e... -- : mer -.w-a :.s).: 9-{m :--- cen ra tor -(Fig ure -1 ~." ,W-W ;;.p..c s.q.,. "n. +'..'.. -5,E.. -....::o ~ v .<g,. .....;-.. :. ~.',.;.; ..v m. .w Wl;s - e-~ 2 ., s. ;, -::.,S.t E'- -v .c .sa .... s. --a.:... ;m, -.... m,. . ".k.4..v. c - .P' .:.- s y.!,:. 4.0 3 Yh.': a f. :: 9...-
~~2.. Y. ;. n. %. s~~
~~- c ?. 2 it interruptY. natural '. ..ubbl.,e forms in the U-bends.G f- - : . /,. If a s te,.:am.n.' . s: u'-~~
~~C'.~~
~~s:,..: .. '^ 3 s ) :.' -~~
~~q?. % :y ;.;.- '~~
.. o~ - M .1. : - ?- ~. ci rc'61atio,n.~.y,="Wat er i'n'.t de ~r'ea c. tor *c.x '-*
~~..- w... :.a~~
.. : a.- vesse1~ starts to boil ' ~ ~ ~ ~. .. = -.. m.,. w... m 7 ,e acressively due. to loss' of circulatin flow. The reactor core t.. .n exit ten era.tu.re and, correspond:..ng. va.cor pressure increase until r .,- o ~ ~.:. a.s.- a ..z. .. e . ~ - the reactor vessel top plenum becomes the cc. trolling high - ~~ temoerature l'o' cation for steam bubble formation. This occurs when the top plenum temperature is abou 1 to 2 F above the U-bend ten.ceratu re. P00RORGNAL ~ 126? '36
temperature continues to increase due to loss of The core exit f flow to the steam generators and inability of the break to remove Figure 3 indicates that this is likely to sufficient decay heat. The occur in the short term fo'r breaks up to about 0.035 ft2.. reactor vessel level which is established in the top plenum when a steam bubble forms continues to decrease due to fluid loss 4 The ste~am through the break exceeding liquid makeup capability. bubble is at a saturation pressure corresponding so the g .h. bend increasin9 core exit te.mcerature. '. The steam bubble in the U- ~ t is compressed and conde'nsed by the increasing reactor pressure. f-The U-bend is refilled with liquid and natural circulation should 3 3: ..e. The restoration of natural circulation reduces core be restored. temperature and corresponding top plenum pressure until a exit g c. . y... new steam bubble 'again forms in the lower pressure U-bend region- ,:.~ ;. w...... .. ;g:.. 3 _.;... y'... .<9-P ~ r and the proces s, repeats,,4,. 1,. ,r, _,. T_ ? .. ~.,..,.,...;. . ?.::.- a .h. ~ ~ -...a.. @_.d:;. x.. -;:. f.. i.e.. once formed, t.1 n],;d.m.E.s.. vessel steam bubble should be sustain
~~4. ~C.~~
~~..the. reactor. ^ J -.f.3w. p>q, .... y r..,....:.;....., :,. y. r.:... g. -.. ,~.~~
~~e. l "n'~~
~~.h.. ^:. 7 andf grow.: larger 'to'.*acco:.moda,t.e the net b'.owdown of fluid from n v.: n, .- e ? w. + ~,. t,v %.s.n.::.m n.w.; c. z... ~:;.m~~
~~3. -~~
.. u.s c:, ~. - =.+y -p.-.c -s i t blished may.- . ~.. s;.z-Q.:,-%=.~Q:.lfip'pg f)g.sisel level which- }s es a ~ sy s t'ein.; ' The reactor ve ..._,-}.. ~,. %?;;}yp_Kl.-);- [. f . experience se.=e small..additicnal pertubations as the steam.... " ;.. -- y ..,,.... c. .m... '. s.. ra.. :sn : ~..- :,.,., %,,..,,, v. ...~~....~~..e.u....'3..,..a...>. ....u-..., w .a ~n in the.rl U-b'end s,Y.t. the..short-term..., v 1
~~u 1es form' 'a d~~
.,.s; q.nd Obnd sse:.% n -..,,,,.;; .7 3. p..,,,,,. 33..;, bub.'5 .,;. p., 3*.~;f.-_ = ., y .,.y,;. g y, A continuatic6 of' decay c. o:. ~ trend should b. e. f.or.-.a. ;;.d.ecrea' sing level'. .....n .7 -n~ should be hea.t removal b..v 'i.nter.mittent natural circulation. ..c m -. .. m.. -. !;.it :- ; h:.,.3 -n.. .a. as sured.' until.' th.e. U.:. bends"can' n.o..1criger be'. refilled with liquid. + v ~
~~g..~~
.,.-3 v +.. s. c.. During the natural circulation phase f ollowi.ng a water-side break, _ the pressurizer surge line and vessel slowly refill with se..i-qui e sc en t liquid. The pressurizer steam bubble is in equilibrium wi.th'a slo:1y decreasing reactor vessel steam bubble P003 BREM }. ' '.._ 7
~~,,.... f,,.,~~
~~. 4~~
~~r... w. ;.,~~
i pressure and is mostly likely. slo *1y contracting as steam from the bubble condenses on the pressurizer walls during cooldown. For a steam-side break such as at the pressurirer top, the break vents the overpressure and flashes any saturated licuid in the pressurirer in a similar fashicn to a water-side break, but the level loss rate will. be lower due to t icwer mass flow rate for steam through the break (Figure 2). When the pressurizer steam bubble reaches pressure equilibrium w!.th the reactor vessel steam bubble, it ' starts to contract rapidly as steam continues to be removed through the break. Fluid entering the pressurizer is at system' saturation co'nditionsi, but some ' pre'ssurizer ~ metal heat ^ input r'emains to reduce the pressuriser le'.el rise rate. The entire steam bubble is' removed' cuickly through the. steam-side break,and it beco.+,es a. water-.si:fe br'eak'. The. reactor vesisel e ..e. A . u. .- v.p-. .._.n. _ 4 4.. =;.., ..r ..,3 g.p drain time should be much sh'cr'ter than given in Figure 5 because. this ficure i's bas.a.ed 'on' a co.n.s. tant p.res.surizer. leve.l.which"is'a -:. ;,:. '^
;L,..r.g. ;g.,.

, :. : y valid assum= tion cniv if the 'steamside. break lis' not at the '..
.: :. c.,,,, ... - g.p'*. z. m'.- ;. %,, 5.~'; n. --.,q,:,., -. e 7.:.' a.. -.;.. pres sura :e r ! top. :.,.f'.f *.g, eN..;g. 9,7...,q, '}. ,.1 ;., g - w..r;.; . y,,p :. - m -.- ~....,;,. - .. :. s --r. q m.. - ~~ :- .s
~~z...-. -~~
..:. t - c..... :.. c- ^ ....;g. .;9 -- ,~ ..=- *.- ':y ~ fio6~ha t o rs1"ci'rculatioD to Pool ' F0iIinC... -~ w . y,; ": ~ w-f-:;.,i,. . ~, .c 322 Trihsition ~ ~ ~ ,a-c ~ -. n -..:. - =.m ; u.: .-b:~.
~~... q- :..... -. -. a..~~
~~. s. -. ....2.,....x.....:.-. ._..y.~ .. _. ~. Natural circulation.' clearly ceases if' the reactor vessel level reaches.the to.o o.f th.e.h.ot le: c. ices..t nd reactor steam startr. to n. o ]. '~~

...g

S y.g
.n, break away ar.. bubble through,the pi;nes and accu =ula'te at the. high points (which are the U ': ends). Water in the reactor vessel starts to boil agressively due to less of circulating ficw. The reactor core exit terperature and corresponding top plenu. steam bubble pressure increase. The hot leg pipe pressure remains '~ essentially ecualired with the cold leg pipe pressure by -eactor ] }.{ } -- ~1 %.....- -. g
vent valve actuation. The reactor coolant pump loop seals inhibit reactor steam entry into the steam generators through the cold leg piping. The water level in each vertical hot leg pipe decreases due to fluid loss through the break exceeding _ liquid makeup capability. Since natural circulation is no longer possible, the core must be cooled, in part, by pool boiling in the reactor vessel with conf ensation inside the steam generator tubes and pool boiling on the secondary side. The steam generatcrs are assumed to be w isolated and pressurized on the s'econdary side to the lowest a sa fety ialve set point. ' The initial ~ seiendary' side liquid level' ' ~ is determined by plant operating conditions at the time of r~ reactor trip.. It will most likely be in the ran Je of 6 to 26 f t above the bottom tubesh P plus any 7.et addition from auxiliary _ ...s. ~ f.re dwater. - -~....,v-n ~
~~f...~~
. n., z.. c .,.e -? 1 The transition, from natural circulatic.. to pool boiling may be .g "troubidso~ne because of' the time de' layi-icurred.while waitinct for-- .i.; ..^ ~ 4 -:- .... s. .. ~ ~ .c ~~~ thI UEt'er leirel"in the'U-b'end. region.~of e'ach hoti' leg' pice and 'in'.# -^
.,v..g ;.

r.
the stea'm lcenerator tubes to drain.belev the secondarv side.wate = Y. . level.- -)uring this ' tide, no apprecia'::le heat is removed by the 3 steam generators. The steam generator frain time is giver. in Figure 6. By definition, this drain 'ti..e starts af ter natural circulation is lost. The drain time' represe..ts the minimum time during which system repressurization e:.11 occur if all decay heat is not being removed through the break. P00RBRIBkl 1269 99 h*be..
~~.e==em m.m~~
...e..em .w
Figure 5 indicates how 1cng it will take for the reactor vessel top plenum to drain af ter a break. The actual higher pressure during a portion of the. drain phase will decrease the drain time. Figure 4 shows how long after a break before all decay heat can be removed through the break. For the range of s:. aller breaks, reactor vessel drain time for a given break size is somewhat shorter than the energy equilibrium time. This means thct natural circula' tion ce'ases"before the break can remove all decay heat. system repressurization will occ.2r as required to remove ~ the excess decay heat while waiting for the steam generators to drain.following the loss of natural circulation. Increasing the
~~q pressure increases flow thurugh the break and thereby decreases energy ervilibrium time for a given break size.~~
It should be ./~- noted from Figures 4 and 5 that repressurizat. ion to 2500 psia appears unlikely since all other curves are to the right of the .r -. .n. 250d psia curve for CD = 1.0 which is the boundi_ng_ condition. ~- ~., %:,...=_,...._-^r.y.,-. ._ in -c .? +. . %. ' ~. - . v- . m '.. ..n u 2;.;. xy. 7 s, p.y. ~. w : %.. - .. -"..+ = .u i i i.s, - ..Although the...results' indicate that..-full repressur zat on ..,.. f.. 4.q .s ..g. t -n ' ' "ir:like. ly7.. it..should.. En... underr. cod t. hat...th'. .. -c.c. ..e,f f. e cts of; ra.r.tia.l.-'.. - -. e' t..... =. ..:...e,,.., s, ... e.,, c- .... n. u =..,. repressurization have not been evaluated in..-~-te rms o f. :- e. v ~. minimum cor..
~~.s. :..~~
~~..a ..:........u e ..( . w.~~
~~~. - -..~~
c. 4. . ;c :.. .w... .'. level. and peak.. clad t..emperature effects... The, cal.culations wh.ich'.. .. =.... c,..,........ we r e per r or me d...,,...,.c, on,.irm t..at..,. u..,......; ,~. merely. c re..ressurl:ation may occur in - ~ order to remove decay heat when natut 'l circulation is lost. Increasing system p: essure increases flow thr~ough the break and i ..e decreases makeup available f rom the high pra-<ure injection pump. This will probably result in a icwer ultimate core level and a_ higherpeakcladtemperature i' the core is uncovered. An ECCS type analysis based on an appNriate..cdel for the very sinall~ break LOCA is required to determine the nunbers. 126? 40 300R ORGINAL ..-.w--... ....~
.d e t During the transitica to pool boiling following a water side break, the' pressurizer surge line loop seal inhibits steam entry into the pressurizer. The pressurizer slowly fills as the remaining steam bubble in the pressurizer is compressed.to system pressure and condenses. The water level in the vertical hot leg pipe eventually drops below the surge line connection to the pipe (Figure 1). Any further increase in pressurizer level comes f' rom water remaining in the loop seal. The, loop seal is soon purged and steam from the ve$tical hot leg pipa passes to the i pressurizer void space as required to compensate for condensation of the steam bubble.. The level.:hould stabilize.. For a stean-side break such as at the pressurizer top, the .g pressurizer may refill before the reactor */essel top plenum is 'drairie'd ' an d'. n a tura l;, circulation. cea s es. It should remain filled ~ (' .~
~~u...~~
~~unless the vertical hot leg pire drains to below the surce line - = ". ^;. s.w ... - ~~~
_
1.- . connection.'..in.this event, water.. flow through., he. surge line to .a.. t 7,..a , ?. gf.v. '.,g..,.,... g ~ the. break changes td stean flow and water in the pressurizer. and.' ' ._..e- ,.w............. ...c..s v v.. h ea te . ch ..... ~. ,~ - -...-.d t. o satu r a ti. n. tem oe r.a..bde 'an.d..pur.ged fro.m. surce..l.s.ne is.w' i .z,.. . ::ii r - ;.i.s +.- ~ Steam, bubbling. through 'the water to reach 'the break '. .,. ::/ ~ the ' system...u ..:. ~ t. t e. -o ~ .e.== =.e .. ns ..T-.'.1;i..,.... ~ .may creite hy.drau.lic.: instabilities. -. n 3
~~3. 3 ' ? col Boilino J~~
~~1V ~ -.;m. y... ~~~
~~h. order to condense' steam inside the steam generator tube it is necessary to d:cp the pri..ary side water level inside the tubes to somewhat belcw the er.isting seco::dary side water level.~~
~~Si. e hot and cold leg pressures are virtually equalized by~~
~~eactor vent valve actuation (..inimum a? of 0 15 psi to open),~~
the primary side water level is the same as in the vertical hot 1w26I '47 / g
leg pipes (except for a density diff erence correction). A porrion of the steam which is generated within the reacter core will seek its way into the vertical hot legs and undergo bubble disengagement at the water-steam interface. T.:is steam is then free to condense inside that portien of the steam generator tubes which is above the primary si'de water level and below the secondary side. water level. Condensate insi6e the steam generator tubes is retu[ned to the reactor vessel by gravity flew through the pump loop seals a. . cold leg pipes. The reactor vessel level (two-phase) fluctuates above an .~ n. elevation corresj:onding to the top of the horirontal hot leg pipes until the level. in the vertical '.ot leg pipes drops to the horirontal hot leg elevation. At that tine the reactor vessel ~ . ~. - :.. ~ 1svel e.itends into the hotflegs. It then decreases until any-I,j.., ,?... fluid lost through the, break no longer exceed i the liquid makeup ' - *.e .n...~.....y..-.. capability. J., er.certain small break I,00A's, the reactor' vessel. level turnaround may r.ot be rea..ed until the upper portion of - o ..,.....m.......
~~4..-- -the core has-been' uncovered for a prolenced time..I'or certain.~~
~~~ Isna11er..' breaks, tu'rnaround might' be reached during the natural~~
~~=. ' %,,~~
~~. =* s !.~~
~~,t'.*.,~~
~~t t* s e. 'y =.'. ;r -,, cliculafion ph'ase or tra'nsition fred natural circi~aticn to pool' ~ i 1 boiling..~~
~~3. 4 mransition ' fro- : col Eoiline to natural ci: culation~~
.rcllowing reactor vsssel level turnaround, the level starts to increase and eventually returns to the tcp of the horirontal het leg pipes. A water'1evel then appears in the vertical het leg pipes. A corresponding level (except for e density dif ference correction) appears in the stean generator tubes due to pressure 9l7 174.0 / r_ Icu/ T
ec.uilization by the reactor vent valves. Anv further. net p. addition of licuid goes into filling the vertical hot leg pipes and steam generator tubes. A portion of the steam which is generated by decay heat within the reactor core seeks its way into the vertical hot legs, disengages at the water-steam ~ interface, and condenses inside the cooled region of the unfilled portion of the steam. generator tubes. The reactor vessel. level fluctuates abo ce an elevation corresponding to' the' top of the hor 3. rental hot legs. The level ~ should slowly increase as the large steam bubble in the upper plenu.m is condenr..under the influence of the hydrostatic head produced by the rising water level inside the vertical hot leg .'i 91 pes.: r t. ~.. '-*- ' ~ . ' ~. De. cay.h. eat.. remo. val.' is acconplished, in part, by condensation ......w..-- inside the steam generator tubes if the prin_ry. side water level c .w.... -y+ 3 - w: r... is su.f ficien.t'ly,. b' blow th..e sec,o.ndarv.' side water level and the - ......u 3.:. _.g.,.S.. nonc onde ns lole.c... ...w.. .. ~ any gases in the. steam generator accumulatio n..o f. -s a .v.. q.( -r.,g;. es. not-inhibi%. d'acuite co$dcniaticn. .. S c tubes do. ..j.." heat renoval. Deca
a'
. p...~ ;;..p; ;.r,,s., t: +~n.g-r;.; -.;.- : ~._ n. ...,.. u. ,.~.. -......,.. ~ e. by;$on'de6 sat'i'o'n 'i:daies'.when 'the' wa'ter 1evel inside the steam ~ ...... =v ;. w ,z generator' tubes.'becomes greater than the secondary side water.
~~- -. ~.,;~~
. - - :... r - - water in the c.- level. If the. break cannot remove all decay heat, reactor. vessel'.. starts to boil more agressively due to loss of one '. p..,.e.... :... of 'the requiEAI heat sinks. 3he reacter core exit te perature n and correspcnding vapor pressure i-crea se until.the reactor vessel top plenum stean bubble becomes the controlling high pressure. F.akeup water continues to fill the vertical hot leg pipes and steam generator tubes. The steam bubble which is trapped inside the U-bend pipe above each steam generator is " "l" F U U H. U n" b M' 126.9..'.43 L.4,.. .J
sicwly compressed and condensed b'y the higher reactor vessel However, the U-bend may contain noncondensible gases pressure. which have ac. cumulated at this system high point. If sufficie.nt (- nonconfensible gases are present, it will be impossible to refill the U-bend with fluid and establish natural circulation. v If natural circulation is re-established, the reactor vessel level is above the horizontal hot leg pipes and increasing, and ' the reactor coolant p.iping and steam gtnerators are full of water..The reactor vessel leve1~continuet so increase until 6 operator action is 'taken to trim back on the makeup rate. ' If r. natti' al" cifc61ation ii'not' re-established and the break cannot r remove suf ficient, decay heat,.the reactor coolant system pressure increases until' adequdte heat removal can he achieved through the s. brea,.k : c:..the..... su.riz e.r s af e. ty.valv. es o pen. '. -4 pres . p....:~...,.s &. -. z. ....w.-...~,.e.:.. ~. -2 At..s.o. e "cointT op>er.at.or action may.be invoked to open the.- .. ~ ~ e.- ..m. . ;. +. :=. :.. ,l.... %. :. -. :..
~~^....~~
pressurizer. electromatic relief valve to assure cc..tinuation of:- - ". i.-dK. q.'~ A W -f X. M ':'.: - i ' ? N' ~ : '., '.* n - ^ th.~e rore.stabl'e ~ mode' of".'poo.l. boiling f or decay heat. removal or-.. .. :.,. :. 1.a. v..e.i.. -.,....,.......... provide suffiefent ~dhpre~ssurization~ ~to 'go 'on shutdown coolinen. - ... ~' v- ~ ~ " - " ~ %:.;.?.;:.;yc.;.. u.::. 9 ;+ '. M.,.- .~..;x..y.p... , : ; a.. y -= - 1. However, r.thi.s valve.,m.has, not, been qualified. -(cla ss, ;I power, etc.) y ..a.-'... .u ,..z.._.m_...._.. ... to perforW an1' essential' mitigating function'and ca: be ._ r .4._. inactivated by a postulated single failure.
t.
u -.2 g. During the transition frc-pool boiling to natural circulation, m...... the vertical hot leg pipe starts to redill and cover the surge line connecticn to the pressurizer. The prescuri:sr completely fills (except fcr noncendensible gases) as the tra. ped / cressurizer steam bubble condenses or is vented through a steam-i k \\p(f '4A
3.5 shutdown _ Cooling ~ In the long term, reactor coolant system pressure will be reduced to below 350 psia by blowdown ef fects of the postulated break. If the horizontal hot leg pipes are full of water at that time,- it should be possible to remove all decay heat through operacion of the Decay Heat Removal (DHR) system. There appears tc be adequate availa'ble net positive suction head (NPSH) at each DHR pump suction to assure acceptable operr. tion at saturation conditions.if the flow rate is kept low. Any fluid still being lost through a break can be rade up by one of the DHR pump loops taking' suction fromthe refue' ling water stora'ge tank or by a high pressure injection pump loop if a postulated single failure (:- - involves one of the DHR loops.- ? 2
~~4. O WORST CASE I.CCA CONSIDERATIONS~~
.- _c.' . ~ ~. n:..e Af ter identifying 7certai.n c.5aracteristics of a very. small_ break. t. g__. LOCA' and' the various modes of pcst CCA' decay heat' renoval, sone. .. a..;. ... r th'ou=h h.- .~..;. - identifi5a'ti'o$o.f $, hA' proba.b. l@ v.[.o:i.s~t case ..was gi.v5n.t "~ ". ~~ _s for. safety analysis purposes.i.-. A. number. of_ consi. der.a tio. ns were ,... x. ?.n. ^ c r. c.
~~. c s c.~~
n -' in'vestig'sted briefly to evaluate' their 'likely influenc6 on.. the ~- worst case selection. The more important of these are detailed be lo w.- &.*..-=- ...w -< n n n 'aa p a ( '.1 Disch::rce Cee f ficient and credk Location ~ Figure 5 indicates a Moody coef ficient of.1.0 inctead of 0.6 for water-side breaks shortens significantly the reactor vessel ?op
~~_enum drain time for a given break size, but Figure 4 shows a conpensating reduction in energy ecuilibrium time also occurs due~~
- 1269 '45
to increased mass flow. The net ef f ect is that only for water-side breaks lers than 0. 02 f t2 with Cp = 1.0 will reactor drain time for a given break sire be somewhat shorter than energy equilibrium time. For this case, natural circulation ceases before the break can remove all decay heat and some system repressuriration occurs. For a water-side break with CD
~~0. 6~~
= ~ the comparable situation develops for breaks which are less than 0.035 ft2 In both cases, the dif ference between drain time and energy equilibrium time is about the same. From the viewpoint of 1 reactor vessel drain time and energy equilibrium time for a given break area, the..co.nser..vative cho. ice;. bye. r.the range examined appears to be op =0.6.- Figure 6 indicates.that a Moofy coefficient of 1.0 instead of 0.6 ~ 'for water-side ' breaks decrea'ses the stea:[cenerator drain time ~ . v..s :, :,.:...... for a given break sire. This assu'res an,e'arlier uncovery of a .q1 condedsin: 5urf ac'e' inside the steam gene'r tor tubes; therefore, a .a
..n the conservat'iv'e ci.oice over the range ex'aE5.ned again appears to
f.
~~be Cy =a. L.'.':.4!. -;:.u;. : a 84:-.u M ": -i..lU <. .. A...4' 0 .U'.~: + }~~
~~C. :.;-,7..~~
~~.' K, a. -... ?. %, '...z... '.l; ~ w...... 'In applying. Figures.3f a:.d 4,.t.o a specific.. break, it should be . =. .r.~~
~~-~-~~
~~.w E ". dater.f.ined that th'e fluid lost throuch We' break remains ' N.~~
~
representative of the fluid at the~ core exit. An arrangement for n. 7 adequate mass transport (wa t er, s te a.m,' 'o r.,two-pha s e) from the -r. ~ m.. u. core exit to the break leratio,n must be assumed if the deray heat o is to be removed effectively by the break. For certain water-side break locations, the high pressure injection mpI) pump flow ay bypass the core and any decay heat generated within the core ..ly not ef fectively communicate with the submerged break or stea.- 126? '46 e .. mo e m =..mm 4
e genera tor tubes. There may be no significant decay heat removal while this condition persists. 4.2 Decav Heat Pemoval Cecay heat can be removed from the reactor coolant system by blevdoun through the postulated break and by a release of steam on the steam ge,nerator secondary side. The break is effectiv6 for heat removal at all times unless it becomes isolated. The s' team generators "are' ef fective only during natural circulation or, af ter the primary side water has drained to below the secondary c. side.' water level. and condensation has become effective.. Natural.. circ 61ation is lost after the reactor.. vessel top plenum has drained (Figure 5). The steam generators become effective again /~' af ter thei, tubes are. drained sufficiently,(Figure 6). The stean I generators are.no _ longer ree'uired after all decay heat can be m removed. throqgh the break trigure 4). m ,... r ., y.,a.,..n....~....,. .,n.. o ~ + The' various modes of p,ost-.LcCA decay he at' re:. oval' discussed in s. ~- ..(.,.. . ection. 3:0(cccur'.unles.s leyel turnaracund develops,.nefore.he . ~
~~s.. -~~
..w .r. .*.:.i. ~ es =:. . pool 'boilirig' stage. [' F.ost water-side' breaks which ca'n be ~ .... g. 9.,._........ s cla,.ssif_i,ed...a.s..:a. LO.CA lose natural circulatien and reach the pool. m boiling st' age before. level turna rounf. Many of these breaks reach. energy ecui.li..brium through the break with perhaps some preicnged re~pr'essurintien hafcre the steam g2.erater can drain sufficiently to become a condenser fc11cwing the 1 css of natural circulation. As a result, corp;etion of the reactor vessel top plenun drainag e through the break (which cul..inates in a loss of .a tural circulation) appears to mark the end of any essential usefulness of the stean generators for very small break LOCA 1269 '47 '$$ $N k
r.itigation. 1:ote that the natural circulatica phase appears essential.
4. 3 Level Turnaround and Enerev Equilibrinn Level turnaround occurs when makeup a/ailable from the high pressure injection (HPI) pump exceeds mass flow rate through the break at the existing system pressure.
Figure 2 shows that at 2500 psia the Ilow from one HPI pump exceeds the mass flow rate through a 0.00 4 ft2 water-side break (CD= 1.0) or a 0.008 ft2 s a steam-side break. Level turnaround should be immediate for these break sizes. If the break is larger but less than 0.01 ft2 for a water-side break or 0.035 ft2 for a s, team-side break, level turnaround occurs' before the system pressure reaches 1270 psia.. Brd'aks exceddi:ig"this range lead to a prolongad" loss of fluid ~ s_ ..n...g.. through the, break with~ pool boiling at 1270 psia until. ll decay a heat'can..be.rencved through the' breSk (uergy equilibrium time) ....yu,>... and thereby further depressurire the sy' stem. Steam generators r r.~....,., ;.-' ~ point cf ca,-d,.ot,[dep'r,e'ssuri, i th's pri.try syrten to ty1:n the. set .~ ... un ..~;.~..--... the secondar ~ side'~ safety valve unless operator action is invoked ., 3._ .,, to?op'en[.'aN.cspheric dump talv.es.. 'The dela'ying dffects of reverse ~I ~
~~v. -~~
n hea transfer from the steam generators must be accounted for when depressurizing through a break at below 1270 psia. Figure 4 '- - } * *" - S -.. show's the energy} eq.:ilibrium tine for a 0.01 f t2 water-side break with C3= 1. 0 o r a 0. 0 2 f t 2 water-side break with CD = 0.6 is over 30 ninutes. A 0.035 ft2 stean-side break reaches equilibrium in about 5 ninutes.
~~atural circulatien must be assured while awaiting energy equilibrium if repressurization is to be avoided.~~
~~P00R DENAL -**6WW-me e e gum.~~
e men..e-

=e
-. enim ,m,.,m
t It is asse.ed that natural cir.culation can be maintained until the reactor vessel top plenu= is drained. Figure 5 shows reactor vessel drain time is about equal to energy equilibrium time for 0.01 ft2 water-side break with Cp=
~~1. 0.~~
Therefore, when natural circulation is lost the break should be able to remove all decay heat with no further need for'the steam generator as a heat sink. For water-side breaks in the range of 0.01 - 0.02 ft2 with C.= 1.0 the reactor vessel top plenum drains and natural D 5 circulation is lost up to 5 ninutes before energy equilibrium is achieved.,, Figure 6_shows the steam generator drain time to be. from 10 to over 30 minutes. Therefore, energy equilibrium is established before' the steam generator becomes an effective heat 'g. sink. Some syste,m repressurization will occur during the 5 s ~ E.' : - minute delay.- "For' breaks larger than 0. 02 'ft2, 3= 1.0, with C energy equilibrium is, reached before the reactor ~ vessel top- .y...\\ .. p.. 4 ,....- 2. plenum drain is completed. + . ' ;- - :.): .y A s'imi1~ar'."5ituation siis ts f or. wa.te.r--sid e breaks in the range of.... ... y... ~ a....w....... ., y. _.. .O.02[..O.03[ft$ wkth 'Ch = 0.6._,The delay times are about the ~~ ...,_. same._. For, breaks larger. than 0. 03 5 f t2.with CD. =. 0. 6,'. e ne r.gy equilibrium is reached'before the reactor vessel top plenum drain. is completed. For all steam side breaks up to 0.05 ft2, the ene: equilibrium r time given in Figure 4 is always much less than the reactor vessel top plenum drain time given in Figure-5. In every case, the b'reak should be able to rencve all decay heat well before natural circ'alation is lost.
Fany postulated breaks change from a water-side break'to a stean-p side break (or the converse) sometime during the accident scenario. For the case of a water-side break changing to a steam-side break, Figure 5 indicates the reactor drain time increases considerably if the change occurs while the top plenum is still draining. Figure 4,shows the decreased cass flow rate through the break when steam starts to flow does not have a detectable ef f ect on the energy equilibrium time if the previous 1.0, water flow is 'for Cp '= 0.6. If the water flow is f or Cp ^ = the energy equilibrium time after steam starts to flow increases noticably; however, s.conparison of Figures 4 and 5 indicates ,-. ~ energy, equilibrium time during the steam flow phase is always ~ very sh. ort wh.en con =ared to reactor vessel drain time.so no ~ reOressurization bfect is ahticipated.. g ....,...x, ., n.. If the postulated break changes from a steam-side break to a ..\\; .. c.d, :, m, ' water. side break..,during the. ac.cidgn. t scenario, Figure 5.shows. p.- ...;,.=. ...... ~.:..... reactor vessel drain ti=e,de. creases narkedly. Th'e break .. mm - c'. :-, -. chara~cteristics b'ecame those associat=d with a water-side break r . _.,, e,.... c. r f T 'and some system'repressurization may occur., This is the type of . _~ ~ m. w -....:.... ~ ~.- s accideni.'se p ence which develops.during a break'at the -' .r=qg - p. ? . r:,- ...g gx. g o-pressurizer tope It initially vents the steam overpressure and 3 eventually passes water.. ,s; m 1.
~~4. t N S S S 'J e n d_o r C?. l c_ul._a t.io._n s A 0.05-ft2 break at the pump discharge is th'e smallest break analyzed and reported by 3 & W using their URC approved ICCS~~
~ evaluation nodel. Their results indicate that one HPI pung alen-is suf ficient to handle a break of this size. Although the P00R ORGINAL 9 D/ . V
reactor vessel liquid volume is shown to drop to the core top within about 10 minutes following the break, the results confirm that the core remains virtually covered with two-phase fluid at all times and the fuel cladding temperature never exceeds its prebrea'< value. Figure 2 indicates the water ' flow from a 0 05 f t2 break at the pump discharge,is considerably greater than the capacity of one HPI pump at 1270 psia. Figure 4 shows hat energy equilibrium through -the. break is reached within two minutes and Figure 5 L chows the reactor vessel top plenum drains in about the same time. Therefore, the steam generator'do'es not have to function as a heat sink beyond this point. Dep'ressurization below 1270 psia becomes possible after energy equilibrium is reached, but the rate will be slow because the. steam ' generator heat must' be During this time, the reactor removed by reverse heat transfer. '. ~ coolarit s.ystem conj nbes t(drain through the' break. Ievel ~ turnaround'_must await a lower pressure and commensurate increase r. in pump f', ou.....'.' ;,_j :.e : .~. M..... &.. :. * --..e It should be recog.ki ed that a ' O.55 fb bre'ak is near the lower e size limit forNh's ECCS evalisatidb.odel" anUnear the upper limit for a very small break LOCA analysis. The ECCS evaluation model does not appear to take into consideration the possibility of intermittent natural circulation or th'e effects of steam generater drain time during the transition f rom natural circu' ation to pool boiling. These effects are important for the case of a very small break LOCA and will be experienced before the reactor vessel level reaches the core top._ They may.at be cc.Esidered important for an ICCS type anal Jg, -' ; ~ l [ l]J g -___.}}h_}..'lg_...
e break because the decay heat rate is in equilibrium with the heat lost through the break in less than 5 minutes following the break (Figure 3), thereafter elirinating the steam generator as a required heat sink. For smaller breaks, the loss of this heat sink and its ultimate effect on fuel clacding temperature needs to be considered.
~~4. 5.3.;eR__ Tsolation ani_Eucp shutgif_.E_ff ects r.ny be a natural tendency for the plant operator to isolate a I:~~
I very small break if it can be. located and valved out. This may I'ran be a requirement of the e=ergency operating procedure or plan. In some cases, such as for a letdown line, the isolation ray be automatic.- Ereak isolation nay be partial or complete as number and size ~. determined by location of the isolating device, \\ of flow paths to'th6 break, and ~possible variation of ef fective ~ break. araa by opening valves. such as the prescu:.izer _ vent valve. --.y Complete isolation deduc'es' the break area to zero.. The remaining . v.. wa ter inven. tory is. determiped by the original break crea and the .._..s..- ..s. _..,. For . stance. if time after break tiefore isolation is achieved., t 1.0, enerr-the original. break' area is _0.05 f t. and Cp 2 a. q.. _lt ~ ,,.... q. e:uilibrium and loss of. natural circulation occur in 'less than 2 rinutes (Figures 0 and 5). At this' time, the break can remove all decay heat, but the reacter coolant system continues to drain (Figure 2). Depressurization ':elcw 1270 psia starts but is i..peded by reverse heat transfer from the steam generators. At S r.inutes after the break, the str.am generator tubes are drained ~ 60,:n to the secondary side water level. If at this time the break shculd be isolated, there is no ef fective heat sink (ua ter P00RORBINAL .. '...-:r.=...-. -e-.. -J.-.R O...T5c7 u-
A cooled consensing surface not established in steam generator). e The system starts to repressurire and refill. However, it takes at least 25 minutes at 1270 psia to refill the steam generators and re-establish natural circulatica (Figure 7 for'Cp =1.0 and 26 ft initial level). Repressurizatica to 2500 psia appears likely with a commensurate reduction in makeup flow and eventual opening of the pressurirer safety valves as required to remove the decay heat. The system now behaves as discussed in section 4.3 (steam-side 1 break changes to a water-side break) as any remaining press'urirer bubble is vented through the safety valves and the 'pressurirer is filled with water, from the vertical ho't leg pipe. The impact and passing of water 'through the safety valves may create hycraulic 1.- instabilities and"other survice' conditions for which the valves ~ v. . -- c.
~~~,,~~
~~have not been qualified. ~ A rapid filling 5f t$e pressurirer free spac'c' with. liquid - ~ 1 - ti... .-r ..c produces 'a corresponding level drawdoen in the steam generator ?.-~~
~~p..,.....;. ;..... ;..~~
....,..x g s,i. y -t ' ' tubes shich tihbn l exposes a ~cor.dendinisurla'ce.' ~ Ehen sufficient ...,.e . - c. c.._ - e .,2 .3: -.. surface is exposed, ti.e safet9' valves no longer [need to open and ~ . ~. .,.s. . ~. the steam ge"nera'to'r tubes start' to' refill. # #After a Ume!'the'# - - condensing surfaev is flooded again and the safety valves reopen to remove the decay heat. The alternating removal cf decay heat through safety valves and by ccadensing inside steam generator tubes continues at 2500 psia. The reactor core should re. main cocared. Ouring this ti:.e the reacter vessel steam bubble e contr:1s system pressure and supports the vertical hot leg water colu..a and keeps the pressurizer full of saturated liquid. P00ROR8NAL-
~~6--M 646~~
.6 m eimmy .afm.. .em L' /
c) c Smaller area breaks which are isolated should behave in a similar P fashion except it may take a longer time'to lose natural circulation. Larger area breaks can also produce similar circumstances if they are isolate'd. A full pressurizer may convince the operator to trip the EPI pump ~ and watch for a subsequent loss of level. If this happens and the break has been isolated, the stam generator tube level starts ~ to decrease due to release of fluid through the saf,ety valves No further 5 until an adequate condensing surface is established. level loss is likely and the safety valves should remain closed. A stable boiling mode will prevail.. The pressurizer should remain full of fluid with a controlling steam bubble in the reactor vessel.. ~ .^ -.\\. t ::,.::.....,'. : - Y . ;.u. ..~ ' ~ > ~- +
~~4. 6 Pres surizer T.evel Indication :, 2..~~
~~.! ~ - A .z e. ~. y,h,t. a.y l-te ,...a. ~ The mode ~s.of decay. heat remoi al discussed in secti~on.3. 0 point C:.,~~
~~n...~~
~? .);. out .:. S.. n. 'i g.. .'. q ifC ;.'n: '....' 1 iL. - p - ' " 't that pre'ssur.3:er lev.el is r.ot" a correct indicatior of water. " .--.e.r,.9..c .y..._... ......;. g.g.. g. .e... ..? ~ level e/er..tbe res.c; tor,ccrei. During '.+thF natural' ci'rculation ;~. - C 26 ^ h:: ..r ..., ~.. phase, water can,be draining from the'. reactor yesse,1,, top plenum.- .w...... , p ;..mg -; 3., - .,...m . r.,:. q..
r.
2 " :-. whilePpres surizer J ovel is s. lowly. increasing..., -.If the.b.reak..i.s: ats ..g c., A.. g a the top of the pressurizer steam space,'a rapid pressurizer During the trans5.ticn to pool boiling and. refilling can occur. while in ;ool boiling, the level should stabilize even thouch the core may be uncovered. derefore, pressurizer level is not -n s. No consice:S a reliable guide as to core ' cooling co. There is a full other primary side. level indication is provided. range level indicator on the secondary s] pf eac' <-te n J generator. j269 754 ~ - . _..-.....~..--.-
i / A similar problem with pressurize'r level indication is found in section 4.5 relative to HPI pump trip. A full pressuri:er may convince the operator to trip the HPI pun; and watch for a subsequent los s of level. Although this response appear,s desirable, a full pressurizer may not always be a good indication of high water level in the reactor coolant system. For instance, the steam bubble which is trapped in the pressurizer may be vente,d by actuation of the pressurizer vent valve due to high pressuredeveloped5.n"thereactorvesseltopplenumorby operator action. The vent valve will subsequently close but the pressurizer [maybefilledsolidwitha subcooled liquid. The loop seal configuration of the pressurizer surge line allows the pressurizer to remain filled as the reactor ' coolant system water level drops..until. system pressure is below s.aturat. ion pre.ssure of. s. y. .c_ the" pressurizer liquid inventory.' This'na'y 'take a long tiine if -e
~~v., -~~
~~~ . system pressure is set by. a requirement to,.removef some of the.,... r. 1.^ .' ; G :. .-L 2 - / ~ decay hekti througli~tlie steam generator at'1270 psia. Thus~a full~~
~~. ^~~
4.. e..:...., 4 x: -.. .r...p. q-p; p- ~. .. ~ pressurizer,is not consideted a reliable indication for-q :.a. i.'. .y...ve78. ..s. ;.;.:. 3.'..~:..: n + : ... n, ,.e: ^ ,.c .g......... prescri.bing..x.-certain operator actio. a:ns.such as EPI pump. trip..,, . ~ e
~~c. a.~~
.s. ~ c.y.. ; :.. .,.v... - .x ~.. .a.: y ...f'.. r- _., q. ...,. g .':.-.....:...L,..'.- ...~... q, ~ y... n... e, ~..... . 2; - .. -..w..... '.' ;n. ...~. 5.O CONCLUSIONS ~ ~" ~ '. ; ;- ~ ~ The results of this investigation verify the pressence of a class of very small break LOCA's {prcbably 5 0.,05 ft2) f or a 3 0 W 22 5-Fuel-Assembly P4R which may experience one or more impediments to decay heat removal which need to be better nderstood if proper operator response and a.' 3uate mitication are to be assured. '~h e folicwing situations have been identified as special items ci concern which require confirmation using = m P00R ORGER M..
a. detailed transient calculaticas based on apprograite syst.em and core thermal-hydraulic models. The reported ::sss vendor models do nc,t appear to accommodate these very sna11 break LOCA situations. In each case, ' fuel peak clad te. perature is the parameter of particular interest for comparison with the ECCS acceptance criteria, but stability of the fluid process and adequacy of instrumentation.and components should also be considered. Intermi.ttent ' natural circulation is identified as a possible mode _of initial decay neat removal :ol. Lowing a very small ~ .s w ~ break LOCA (section 3.1).'. The adequacy cf this unst'able mode for. decay heat removal needs to be. verified. ~ 2. The transition from natural circulation to cool - .Z:._.. ~ .. = ,=..=.. u,..... <.-L...,: -. ~ ,.....o.i ll.,..... -...nc,'conds.wi.w. 2.nvol s es. a. tiu celav i..curr. +. while.. - b . e. w.,.... .c. . waiti'n up....y. x. g foi'. water -inside the stean cenerator tubes to drain ' , g.... i u. ~ g - ~ - below. the secondarv side. water-level ^ (se:-ion 3. 2). During-f':.'-;i- &.f*.{,$-.7f.y.,l* ~- . f.. g... _.3 thisi.timi, system re cressUrizatien will c.: cur.if all. decay' ~ ._ '.Y. y.Q ' -l. ~ $ 5 ? _:'..D. :M :.. @ ~ 6 1. E..:. Q-T y '.::...- ...>. heat *is.~a.w. y... not b... removed. _ h~ rough th. _ hisak, The ffect,and ' ~ '3' eing ~ t e . ~. ' .,e .. m., ~. - -, x. .-n.. m. n. 2. Z..acce.ptability.' of. t,h ~.s re pr. essur.iza tion. n.e ed s to be 1.. _..,.v 1- >. v :. - -v - -.:-. +- ~ ~x :. ~,:..m:: ., ~ ~~..- -. -~ u s- .:- = ;.-.. - - g ggg _m$n gg y =. :.. r; n. ~.. e. 3. The decay heat fraction which.is re..oved throuch the break
~~4...~~
..:3...y . for a given mass flow rate will be less than pre 3icted unless the fluid. entha13y upstream of the break '.s representative of the core exit enthalpy (section 4.1). The sensitivity to upstream enthalpy, particularly with regard to system repressurization, needs to be evaluated for those break locations wherein some core bypass .ay be possible. m m P00R ORGN2
s p 4. The pressurizer level indication is not a corre::t indication v b-of water level relative to the reactor core (section 4. 6). The safety significance cf this shortcoming needs to be evaluated with regard to adequacy of information for corrective operator actions. 5. The possibility of very small break isolation by operator ' action and 'the subsecuent loss of both the steam generators .and break as heat sinks is of special concern (section 4.5). The~ rapid repressurization and eventual exposure of the pressurizer safety valves to slug or two phase flow needs - nd possible test n-further analytica'l consideration a. qualification of the valves. There may be a potential for serious process disruption or 6..-o .. m... 'unsccep. tab,le functional or t. ressure boun.dirv. damage,to. ~ - - . ~. c c. "~~ cp=conents"and steam generator tuhes due to the hydraulic -s .. m...... ,3-i. 4 - instabilities which are'likely'.to develo.: during a'very small. l +..,.;.y y:, q 5-. ' ' break' Locrf The bubbling.cf saturated s eam thordgh '.... u.t..r.~. ,, :....,..- v. -.r...s...
~~x -;.. ~;;..,~~
liquid and the injectica of' co'.d makeup dater 'into . ~. 'J-~ - 7 subcooled ~ - n.:.r'-;. w'- .y. .g ~ ~ ,'.'.1., $i stea(~f E11e'ck c$id. led '%.ipe al.,e ib.h'ere'nt.i s.-.. . unsta'blef ..?..,s ses o.f particular concern that' need further ~ ^ p oc m cor.s id era t ion. - L P00RBRSINAI. m- %I ml J v ~ ~
. Lv. 1 p. w N-. FLOW ARIA CORRISPONDING TO NOMINAL PIPE SIZE No--inal_Ei :e Si e (in._1. Sjegule Ep..,,, Flow Area f ft 3 = 1 80 0050 ~ 1 1/2 160 0098 2 i 160 0.156 ~ ' 2'1/2 160 0246 3 '..
~~160, 0375 t~~
~~160, 0544 4 s . 'Pe.t.en.tl.a.l singl.e-en: led circu.ferai.tial.-br..eak a rea. .r.-. e. .s. ~.. .s. f..p._; -.. ^ W.~~
~~c. _....~~
~~g. p., c ~ - r ..>. ; i- _ u- .......,...,.. :.r~~
~~s. ~.....~~
....... v, -.....s.,, gr > *..:s...:.u.. : .. ~.. _ n.. .,a.. w...... ..s... .y. ......,:...,.u,.. ,. r.. c a.... ..a. .. n.. .... s. .s..,.... ~..y.. .._s.. y,. .. a... .a. s-I. ~~ $ 4.-. '.*(. ' '. Y.r_..,. . C# '. '! '
~~s..~~
~~i.1 M.~~
~~4 s.~~
u.e .4..,c :e a ,.e. e. .c.. . sg 7.. -...., = .r. m g I s p P00RORGNJ1 .s-s I t . e 30 . =.m .m.s.u. m M.- _.mu.e .e..m e. w e..= e.e -.ummu. e. .-e e. .- * = > .e. .we.- . * = - e m.
. '? e G / O \\.. U3 t1 5 4 J n-i I .8 e 5 c O D %D b. t!N y;, t y i f V D e ,i s,. m -- 9 2.! ee - J, ,,. a.. O P l !*I l 03 [ O t-I
~~3. ml w, -~~
i !.y Vg u os I 1 wO I *e i 4 ts J gy I g. tJ e dg N m m y u ,.s t O _w.....w =*.9.. e .t 1[ e; i f s .i I 6 .m t g I MN1 ~ .r 1._l= -. _a.. 3 y rW ypt ^ Q , =.' ._R t h, O .-.....-~...'..k.'.3 iEEcm .-2.
~~~-.c. -~~
= s.=-== A n.s =.,;* ..,,.-.es-u.. e ..s. -..... g. t' ~ 1. ~ .' r.:: - ~- - L O Lm sL).r '. 1 ' ....r ~ 7- . r.,. .%..., ;..., ~ = *.., ..,l '! // '& A .. '.').- .I s. z..... - ~ ! *y I, i,. sg ?}g l.g y ,4 ,,..u..
~~3... '~~
~~,~... a;= ~ i l 4. g v,. ; -.., n.. 1 gl g t .I ~ q;. .e. s; t ,.v.~. na. g - - sj ' 15~~
~~v.. ' -~~
~~~.'*.-.s.....~~
~~,;...r;...~~
~~e g,g. j h .ID I. .$g '.,,.....+ ~;. r w,~~
~~.f,~~
~~...2l fg , = ye ~...... j, 4 f[ --. s y;. - w y. } I, g k.. f r. r.!.$ji ~ f. / A ,2, - ~ - ' = n. 14 i. /! R tr.s l ,j_ i s f,/ .) l ~ i n ( l l t ~.A~~
~~I l~~
f l t f o / I T T z .:, m# i ;p l i a. fA. -- t ,l g 'I r F al 9 [ p P00RORBLL l ~'? ' o r ..... n....
w e. l m% s M L (. k I Q% M s hE k R 't g Q-S %4 3 +, k s s.D -h V .S "Q'k N 7 N ~ N \\ N5 h 9 % h l T 4 Sk s 's s kk 3-l kk N 's N '.s y ' T4 S kQ D ~ k5 i. N s. - A s s s k - --i s s \\ s-s q g N s s I a N ( "D k s a a 4 s ,k @e Q S k' Q (7b201.:r").tNIMJd) C& CW H lVJO JV)?? \\ f
~~~. ':.. -Q.. ~ *:m~~
~~'. X;'.,2. l ~.;. ~ '. ~~~
~~I-[..d ** *-[,,,,.~~
~~4, 3... **[. -'h .g,~~
~~; **.s.~~
~~. x'~~
~~a. 'l. -Q ' ~ : f.~~
~~. y-h.:.:. :. a. q., a.. '.. !..~~
~
'f 5:"* -l ' \\,,, Q *i**' s ~ 6* y - ', t ?;- '; .5 S: ' I.- V. s' 4 t \\ .T -Q,R l .s.' W - -~. g.$. *
~~.%.'.'.^;,.* d\\ -~~
~~- g '... f..j (.- , v; y y g s, yA s g c e,. s. 9.+. c. lb4~~
~~~NN~~
~~% \\ C4 -' I.'a..'I .3,. a.: 4,\\' r% ' *. .. j. m 4'~~
5,*
j
g
~~. - - l q.~. ~ ' 4 a . Q.. ~. c .. _; -' ^ J.,.,. -,.y;.... p%... v : '.*. M, - -- ,s . :. a. - 4* W. .y::,.s< y.,. ~ ~* Q. .. o,k % p s.. a~~
~~' ~~~
\\ ^ \\' d g }4 '.:1 : o-.. g. q - u. c, .g - s O.,, - q. .. ~ g ....e...j..... s - f.. s. ~N ~\\.., g . g #o" \\~. \\ Qtg ~ M ,k '(. ' 'N. !'\\ g \\ 3 s w g-- s.'s N N y Rt s s N'i's \\ gg. 4 e g3 Ns \\ W N 2s i' \\ %S i '- i ~hh \\ I -a i a, e b e 4 n 9 4 (2IS/??7,).Y (.'/b' /.07.? SS:-W 2HL WA//h".U S un m P00lFOR K.
..s, r k k N h t s b _ _r/M. st z D k k ta m ,_ a.. -> E t- -i N wm-a a.. r.0) y q% c \\ ~ k, u ^ gh S, bw S 4 g R (N/W) SWIJ. NIYE'S 7.ISSIA O'CLVIN' QL ~ ~ SQ,, ~ k t, 'N ~ %y u >_ g 3 g. x z q- ..7 g& r ;.i .~n-1,.. E' .t //.. f.~ .. i,...t,.,- f g 3. 1 g N /' R .i I I D
~~3 I~~
/: N .s ~ gg .A ls.. -N'. ~~ , N ti u,k,% //, x su /* ( Q 's/ s ,a sq / G w-Q t s d %AOD .4k u R si 6 4 s' )$ ra.uv av.a nweeninx uni.: @8 P00R D S M q n 7 1 ._.-....? ___t 1_
up e . d.* C D .e. 3 s \\ ~ g h \\ N \\ N N g \\ O. \\ tr._ o, O.N 6' Q O,N o Q N
~~g s o%~~
~~y s.~~
~~s, T-k~~
~~.a a _'4 4 h* s N A 3..Q( s. N ~%M 's 4 q, u ,~~'s-o g - )3.sl 97 c q ' '4 O'/ % % @ q-N 3 g% a s I g R, R. %g V.wa sws.i 17:=w cs t: 5% .. ~ -~~
~~i...... - - *-..~.:.~,. -~~
~~l' - ~ ~ . i. .. - -~ ,1- ~ ~ ~ h.-,.'. -.. e 't ~. ... ~.. ,r.. s ~ EEaL,~~
~~1. ' -~~
~~'1 s c . :f.. ' p.2.~ .s y s M7 f g p'- x.;.;. l f (... .; +. f.h . s,I ~ k. .. 5;;. L. _. i c i. .. / c. -. 2.o... N..~~
~~g Q.~~
~~/ , ;.q - k '... ; '.. y .i, ' ' k ..- ~; c.* s. ~ '.3_ y,. . w. h" m ~~~
~~- w~~
/ 7.,...... e. - nj.. - .,, g c,, c > / {N 3' ( h ( 4 N- , var;? m / V. %gg S H.? % N %Ni ~&. k 7;-: --y;p ri s ICE S U Q'., g 'q ~ n-g0 y _ N s g. i I .c S5$ s l% k55 tss s s e %w M e% cisa.o.u.u n = ->s-P00R034,3 126? '62 -....}}

ML19254E918

Text

SUMMARY

5.0 CONCLUSION

Navigation menu

Search