ML19322C562

Discusses Potential for Operator Action to Terminate Hpis Following Initial Stage of LOCA

ML19322C562
Person / Time
Site:	Crane, Davis Besse
Issue date:	09/24/1977
From:	Dunn B BABCOCK & WILCOX CO.
To:	Taylor J BABCOCK & WILCOX CO.
References
TASK-TF, TASK-TMR NUDOCS 8001170890
Download: ML19322C562 (2)

Text

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,f Iert M. Denn. F2:ager. ICCS Analysis (2138)

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o:ersect Interruction of Iigh Pressure I:1ection i7...............................~......

February 9 "1978 -

This =e=o addresses f y rdous concern.vi."- ICCS Analysis abou:

.tential forcoperator_accien to ter=icate high pressure.1='j' ction follow *the 'po ' '

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ing the initial stage of a I.DCA.

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. Successful ICCS cperation during s=a11 breaks depends on :he accu =ulated reactor coolant syste= invei:ory as,well a the' ICCS _ hjection rate. As such, it is.=andatory tha': full injection

, flow be r.ain:ained frc= the pois of e=ergency sciety f eatures actuatica *

.systen (gSFAS) actuatica u=:11 the high pressure injectica rate can fully

- ec=pe=sa:e for the reactor heat Icad.. J.s the i=jec-ic:

the reactor coolan:

rahe depends en r..=4:ch-up occurs is variable and ca not.be specified as a ff=ed nu=bers 1: is quite pessible, for e=a:ple, -that he hi

...successfully =atch up with all hea:.scurces..gh pressure injection =ay ti=e : and tha: due to sys -

o.he pressurha:ics be i=adequare a:.sc=e later ti=e t df 2.'

. The direct eencern here rose out of thehecent Scident at Tyleco.

the acciden:

Durbg the; operator te==inated high pressure injec:fon due to an ap-

. parent sys:e= recevery indicated by high.. level within the' pressurher.

' ".. This actics vould have bee:

..been in a subcooled state.

acceptable only af ter the pri=ary syste' = had * -

A=alysis.of the data from the transient cur-rently indicates that the syste: vas in a two-phase state and as such did

..=ot con:ain sufficient capaci:y to allow high pressure injection ter=ina '

tion.

This beca=e evident at sene 20 to ~30 r.inutes follering ter=ination 4

of injection when the pressurher level again collapsed and i=jection had

• to"be reini:isted.

vare[ continuously losing i=por:a :. fluid inventory even though J

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surizer indicated hi h level.

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S I believe it: fortunate that Toledo was at U...-

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..cn ex:renely low power and e=:re=ely low burnu'p.4 Ead this even:

An a reac:or at full pever whh other than in'significan: biraup it is '.

N N-occurred

),.quite pessible, perhaps probable,. that. core uncovery and possible fue1 ~

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dsmage vould have resulted.

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? ;o reactor opera: ors :in the area of recevery fren I,0CA.The incide The following rule is based on an a::e:pt to allov ter=i=ation of high pressure injec-tion only at a ci=e when the rese:or coolant syste= is in a rabcooled

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c: ate and the pressurher is indics:ing a:

leas; a ner:21 12 vel for s=s11 g.rcaks.

M; hat during any follow on transien:Such conditions guarsn:ce full syste= capscity and th vould be no worse.thrn the ini:ini accident.

I, therciore, 'rcte==cEd that operating proccc'eres be 'vritten?

to allow for ter=ination of high pressure injection ucder the folleving

.a ccedi:fons only:

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low prciure injcetien has baca cetuated and is fievu.g at a rate 6n r. ~ n.,... u

,o eicesT5f~1hi high pressure injection capability snd ths: situatien

. has bosn stabis for a paried of c:*.=a (10 cinutes).

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2.

Systes pressure has recovered to ner=al operating pressure (2200 or p

Icqual to the nor=21 operating condition (605, hot leg gs less than or 2250 psig) cnd 'syste= temperature -ithin the I or 630 F).

I believe this is a very serious =atter and des.erves our pre:pt attention *

. and correction.

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E.A. Karrasch E.A. Eailey

3. Kelly

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