ML20024C785

Expresses Concern W/Eccs Analysis Re Operator Interruption of HPI Following Initial Stage of Loca.Operating Procedures to Allow Termination of HPI Under Stated Conditions Should Be Written

ML20024C785
Person / Time
Site:	Three Mile Island
Issue date:	02/09/1978
From:	Dunn B BABCOCK & WILCOX CO.
To:	Taylor J BABCOCK & WILCOX CO.
References
TASK-02, TASK-03, TASK-07, TASK-2, TASK-3, TASK-7, TASK-GB GPU-0550, GPU-550, NUDOCS 8307130288
Download: ML20024C785 (3)

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THE DASCOCX & WILCOX COMPANY -

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' POWER GENERATION GROUP ge.ra e. Ec bo l61  ! -

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.4-. -~ Jim "avler, Manager, Licensing kl Cams _

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7 Bert M. Dunn. Manager. I::S Analysis (2138) g. !M

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Data Doerator Inte m teten of High Pressure Iniection .

yebr.zarv 9, 1975 g . .. . . ... . . -

This zano addresses a serious cancern vi:his ICOS Analysis about the po- '

tantial for operator action to tar =insta high pressure hjectics follow-ing the ini:ial stage of a LOCA. Juccessful ECCS operation duri=g sman breaks depends on the accumula:ed react:r coolan: systa= i=ve=:ory as well as the ICCS injection rate. As such, it is =asda:ory that fun i=jec:Los flow be =aintained from the point of emergency safety fea:ures actuation system (ISTAS) actuation un:11 the high pressure injection rate can fully compensata for the reactor heat load. As the i=jection rate depends on the reactor ccolant systa= pressure, the time at which a compassating match-up oc, curs is variable and cannot be specified as a fixed number.

It is quite possible, for azample, that the high pressure injec: ion =ay successfun y = acch up wi-h an bes: sourcas a: time t a=d that due to sys-tem pressuri=ation be inadequata a: some later time t 2+

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The dirac: concer= hare rosa out of the recent' incident at Toledo. During the accident the operator term 1=ated high pressure i=jecti n due to an ap-parent system recovery indicated by high level vi:hi= the pressurinar.

This ac:1ca vould have bes= acceptable only after the pri=ary sys:em had been in a subcooled stata. A=alysis of the data frem the transie=t cur-restly i=dicates that the sys:em was in a two-phase s a:e and as such did not contain sufficient capaci:7 to anow high pressure i=jection ter=1=a-

tion. This became evident at some 20 to 30 mi=utas fonoving ta==ination e -

of injec: ion when the pressurizer level agada conapsed and injec:Los had

,,,-. to be rehittated. During :he 20 to 30 minutas of noni=jection flov : hey were continuously losing i=portant fluid inventory even though the pres-surizar i= dica:ed high level. I believe 1: fortuna:a that Toledo was at an az:remely low power and ex:ta=ely low bur =up. Had this event cecurred in a reactor at full power vi:h other than i=sig=ifican: ournup 1: is

• quite possible, perhaps probable, that core uncovery and possible fuel damage would have resultad.

The i=cident points out that vs have so: supplied sufficient infor=ation to reactor operators in the area of recovery from LOCA. The fonotring rule is based on an attempt to auov tar =1sation of high pressure injec-l- -

tion only at a time vben the reac:or c: olant sys:em is in a subecoled state and the pressurizar is indica:i=g at Isast a nor=al levef breaks. Such condi: ions 31.arantee fun system capaci:7 and thM s .

tha: during any follow on.::ansian: vould be no worse than the 8 -

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l I l acciden:. I, therefore, reco= mend tha: operating precedures N ..'_.. <= {

l-to anew for :aren:1on of high pressure i=jec: ion under the fonoviss two condi:1ons only: .Jirrs anre Iz. Ogg = = T25758 6-/7n

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1. Low pressure injection has been actuated and is flowing at a rate in excess of the high pressure injection capability and that situation has been stable for a period of time (10 minutes).

2. System pressure has recovered to normal operating pressure (2200 or 2250 psig) and system temperat.urs within the

1. hot leg #is less than or equal to the nornal operating condition (605 F or 630 F).

I believe this is a very serious matter and deserves our prompt attention and correction.

BMD/1r ec: E.W. Swanson D.E. Roy 3.A. Karrasch E.A. Bailey J. Kelly E.R. Kane J.D. Agar

. R.L. Pittman J.D. Phinny T. Scott p

COU2KIL COUNSE OLY T25759 .