ML20024B327

Forwards Response to Re Small Break LOCA Analysis

ML20024B327
Person / Time
Site:	Crane, Bellefonte
Issue date:	01/23/1979
From:	Mcfarland J BABCOCK & WILCOX CO.
To:	Patterson D TENNESSEE VALLEY AUTHORITY
References
TASK-*, TASK-06, TASK-6, TASK-GB GPU-2448, K-5020-4-27-78, NUDOCS 8307080438
Download: ML20024B327 (3)

Text

..h_,

..~...++--..y,__s

. -.. ~.

w..

L,. L,.... -.~w.. best C09y b k ;.D i b :

.,O d V Z 9,% %

J:?. :

.. g e=.

nw

.s

.c g

~

BabcockONilcox

?

Pcwer Gemerat>ce Grous y

p..

P.O. 2:a 1250. Lm:vrg. Ya. 241:5 J*

Tele:ac.,e:(604)354 5111

['..

g.

_.m.

~

January 23, 1979 f

. '.~

r.

x Letter so. D-3132 p[-

r W

File Ref: :;l.M-2/12311.

.d.,-

Ref Ltr:

K-SC20/L27-TB g,1 g--

T b'

y p

Tennessee Valley Authority T.,

kC0 C==erce Avenua

'.'..u

"'I.

. U: ?). -

c Enerville ::: 379C2 ~

D g

.. ~.

~;

Attentien: Mr. D. R. Pattersen S

gee. ::ss 15/16 S. 2 J

Cnief Mechanical Engineer R C Jcces

~C B M Dunn E

Bellefente Hueles.r Plant Units 1-& 2 g

Contract No. 71062-$h11 6 2 y

B&W

Reference:

3::S-15 & -16 i

Subject:

S-=" Break LCCA Analysis

?-

a. -

,,...a Gentlenen:

i.

k The attached report is in respense to yeur reference letter. Please let r

us kne.r if further d.iscussien is ret;.:1 red.

t.

3f Very truly yours, t.1

• [

s:

Ja=es M:Farland l

K Senic: Project !*.aneser h

hfa 1 n

7 Robert I. Lightle F.

Assceiate ?r: Ject 'anager

~

REL:dc Attachsent cc:

V. 3 rent *.*aie J. L. Atchisen E. L. Legan

.r 4

J, i *s*4 mas e: 1357 The Bs: ;:n!..'.a::s G:-:

t N

--N-g i

8307080438 790123 PDR ADOCK 05000289

=

P HOL m

, g g\\

W-b__-

,_,--i

. 2.!.-W 0126 M, 'f" 4 '.'

3

_ -. _ _... _ _ _ _. ~..

w-~ -~~ ~~~~*

,7.* --m ~~7. ~. -~' ~ ~ ' 'y

,.. =.. _, -- -m w. -~ -- n. = 7 -r --,v

~ w.

v

,,. ~ -

.m..,

..s

,. p. e.,,

4

.~, A... c v[ % ;.w i best copy R v O N^ w w-m on...

. p r

x -

^ ~ -

- '~-

At cch-en:

7 D-213p f

\\

J

• ~

c.:.

n Response to 7/A le::er K-50:0, Sce:;ency Core Cooling Syste: -

$'I F

ses11 tres> t.ccA A.s!. sis :: F-2-14 U2.1. As:(1 27.1973

f. '.:-

p-u;

..:t.

$((.

'~

Via r/A let:4r K-3020. TIA :;2:ssisted to 3*.*=* a repor en:1: led, '* Decay Hes:

Rc= oval Durin-a 'lery 5:211 *0CA for a 3:/* 205-yuel-Assc=517 F:.7.." by C.

}itchelson, a.:cd.!anuary, 1U 3.

This repor: presen:s a si=mlified, hand

-?

~

calculation review of the r=all bre:k transient and potential consequences

?f.

for very s=all breaks net eclici:17 ex:=ined vi:hin :he s=all break topical BI,,

for the 205 7A plant, 3rt-1007!.A. Rev. 1.

Wi:hin :his paper, the fo11 cuing F-;

T concerns were espressed icr :ne very==all breaks:

Rt m'

1.

How is decay heat re=oved?

S

.~

p,

\\

2.

L'ill sys:e= repressuri:stion occur? If so, could a e =tter case be a g*f>

I, vorst break?

m m

If the operator isolates the break, vill system repressuri:stion occur?

4 3.

If so, vill tha pressure relief valves be subjected to slug or two-phase fabi flow?

L

=

V Rasponses to these c=ncerns are developed in the subsequent paragraphs.

e. j.-

E Before discussing these concerns, a general overview of the s=2).1 break tran-h.:

sient in a 352 205 plan: seeds to be briefly discussed. 5:211 LCCAs es: be viewed as a slow transien: during which the RCS can be described as a sealed

[.i q

Because of the i= ernals ven: valves, no extensive stes= bubble F

=anc=eter.

vill form within the rea :or vessel while any significa== liquid inventore re= sins in the loop. Y.asy experi=ents have been run which show that so Iceg C.

as a fluid, -ith quali:1es less than 70: or so, covers the cere, no adverse p' ~

core te=persture excursien vill occur at decsy hes: pever levels. Thus, any 1

proble=s with s=c11 breaks vill only occur af:e: the RCs loops have depleted k

{L thnir inventcry, r

E Decay bea: re= oval f::= the core region is no proble= as sta:ed above. 2:v-C ever, decay hes: re== val f:c= the syste= as a whole needs to be exa=ined furcht. There are :vo vays cf re=cving decay heat from the sys:e=; ria che i

break and/or via the stem: geners:::. So:h of these ite=s are discussed i=

r detail in the rtA le::er. T:: :he very s=.11 LOCAs cf interes: in this dis-E cussion, it vss shown :hs: the break 21:ne is no: c:psble of re=ovin; all :he decay heat and hes: re=cval via the stes= geners:ar is necessary. Lnile the L

T7A-predic:ed break size ::.:: this oc:; s s: vas no: checked quants:ively.

the actu:1 break size :ha: it occurs at is ine:: sequential. Such a break

[

si:e does exist where the s:e:: geners:c:s ::e necessary.

3 The role of :he s:e = ceners:or.ss a hea: re=ovs1 source is basical?y as

^

described in :he 1e::ar. bi:is11y, n :ur:1 circulation vill be ::in::ined in the syste= and :he ne:ess::y he:: re eval is easily s:cca:lished. C ce a s:c:= bubbic cf sufficien: si:e necessary to fill :he C-bend at the cep of the h:: Ic:s is for cd, n::ur:1 cir:u12:1:n vill cease. The inter =1::an:

, natur:1 circuis:ica di::usse: in c.c le::e: vill ne: :::ur due :: :he 41:2 osture ef :he s all bru k ::.nsicn. 0.:e n..:u::1:1 :uis:i:= cesses, :he l'

syste vili re;;e: sura:c senevns: until the 50 ;; :ary side licuid icvel 4;;;s L

j l

r 1

r

~ -

e-

s. i.y. - -:..,

w.

.c 1 <-l G' W L ~ N.E'sc.

W H 3 u:Sih 37.,2i..7J.._...r..

h 0 1 2_6 E

",4 i.

nm m

e.,-

m._

m.m.m wn~.

..- w _g.r e..:.-.~

e n...+

.-.. m

~

~ v 6 pf 7,..~

i -

. -.. ;..,,, y.. -

y93{

gggy w w. m m%-: -

v :.,

~

s

,, T vQQ(

&: m*RD W -i.

S N.,:.Hi..

W: o ;.

,w

/

.C

/..

w 1

/'

below the SC tecondary side icyc1 s=d ceniense: ion he:: c :nsfer is estahli:hed.

g--

re-

' [,

During this pcried be:vecn :he ns: ursi cir:uls: ion and conden:s:ica hes:

[

oval codes, the 1.::c; unp;csses conec ns ths: the liquid inventor / vithin the sys:c vill bu dc;.le::d 1c s s:e in excess of :he :stes for the bresks y

analyzed by 311.* be:suse of the par: :1 :e::assuri:s: ion of the sys:es.

'I.' A 3

is cencerned :hs: this ui:1==:cly vill resul: in : ore core uncevery ::an ::a:

g.;

sheva in the s=all b e n :opical repor: 2A*.-100NA.

nis is not :he esse.

E~. I.

During the ns: ural circuls: ion phase, it is obvious : hat the s=:11er the bre:k, the slower the loss of sys:e= inven:ory and the longer the period of naturs1 g-circula:1on. Af:e na: ursi :1::uls: ion ceases, sys:e= pressure vill be cen-p l

trolled by a "volu=e balance." nat is, the syste: pressure vill balance at p,

a point where the vole =e of fluid discharged :h cugh the break equals the R

volt =e 4f s:cas being crea:ed in the en:e. Since the cold le;; fluid enthalpy pi a

re=ains unchsr.ged durin:; a==all break transien:, the volu=e relief out d.

the break incresses vi:h ine: easing syste: pressure and break size. n e vol-if t=ne of stea= being genera:ed in the core decreases with increasi:3 pressure.

J As the break decresses in si:a, the F4: syste= will repressuri:e :o a higher E

value; thus the volu=e relief out the break necessary to =atch the volu=e y

of stea= being crea:cd decreases. nerefore, the system inven: cry vill be p

lost at a slower ra:e as break si:e decreases. Once the 50 beco=es available

[

7 for condensa:1:n heat re= oval, the pri=ary syste= pressure vill depressurize i

]

to approd-'tely the 50 see:ndary side pressure. Since the secondary side

{l of the SG vill respe d in a si=ilar canne; to tha: of the 0.05 f:2 break p

analy:ed in the topi:al, the pri=ary side pressure response, fc11cring :he c.

advent of cendensation hea: re= oval, vill be si=ilar to that of the 0.05 f:*,

}

break. S us, for the s=sile; breaks, the system inventory vill always be f

greater than tha: for the 0.05 f:2 break and the core vill always re=ain p.,

covered and v111 not undergo a te=perature excursion.

p E.

• In the paper cer.cerns are raised relative to isolation of the break after y:

nstural cir:ulatics is los:. n e scenario presented in the 1e::er is :eason-y-

([

able. Should the break be isolated at tha: ti=e, systes repressuri:stion to the pressurizer safe:y valve setpdin: is probable. ?.o-phase or liquid flev through the safe:y valves vill also probably occur. Once the systa= depletes y

sufficient inve=tery to es ablish condensation heat ::ansfer across the SG, T

the syste: vill depressuri:eend :o further loss of inven:::f vill occur. Se I

core vill re=ain cevered fer :his secensrio and no te=peratu:e excursica occurs. Sh:uld :hs pressuri:ar safety valves beco=e ds=sged because of the two-phase flev cut the valves, :he response of :he sy::es would then be si=ila: to :hst presen:cd in :he FSA?. for the pressuri:er safety valve s:uck

~

open acciden: and no core uncovery occurs.

As far as the appr:pris:eness of :he opera:or using pressuri:e level indien-tion to trip the E?I pu=ps, 31*.' agices ths: the level indi s:ica is nec a reliable indies:1:n of :he sta:e cf the ICS. however, use of :he pressuri:e level indi ::len. 1:n; vi:h syste te=: era:ure and pressure =casurc=cacs :o ensure :h.: the sys:e= is s:ill in a subs:en:ially subcooled s:a:e, vill pro-vide sufficient guid nce f:: operator action.

e

• In su=-dry, while :he

.'A ; :.: ::ises valid ccaccins and gives a det:iled k

exs= inn:1on of the s=sil b:c:k :::nsien:, the s=:11 bien ::d:ie:1 re::::

provides suffief n: :n:1yset :o ensure the 2b111:y of the 3

• 05pihn: I :S sysec= ta ec:.:::; s=:11 b:c:k in :ne ROS.

=-

.. a.

.m #w.

.n mw%=y 4.r;.a.g3. s --..&o.

+

m-.

- m.e,;e.

... %e.

a

=

L 4:9 9 g,4_

H 3 M.. M M F-. J.. G..

_. _ _4..

012s u