ML19308A687

Requests Engineering Evaluation of once-through Steam Generator Level Due to 791012 RCS & Steam Plant Parameter Deviations.Transient Effects on RCS Loop Flow & Differential Temp Should Also Be Evaluated

ML19308A687
Person / Time
Site:	Crane
Issue date:	11/05/1979
From:	Jay Collins NRC - TMI-2 OPERATIONS/SUPPORT TASK FORCE
To:	Arnold R METROPOLITAN EDISON CO.
References
NUDOCS 7912040073
Download: ML19308A687 (2)

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l Docket No. 50-320 Metropolitaa Edison Company f

i ATIM:

R. C. Arnold Seafor Vice President P.O. Dos 480 Middlmtown, Pennsylvania 17057 Gentlenest l

SUMECT: BATURAL CIRCULATIM.

i On or about. October 12, 1979 it was observed that reactor coolant system l

(RCS) and'staan plant parameters deviated from expected natural circula-tion behavier in esejenettom with' the discovery of erroneous once through steam gemarator (OTSG) level measuremen:t.o. During the transimat and since them, the following items were noted 1

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(1)~ The average primary loop "A" differential temperatures have

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l risen and are approafmately higher by 10' than previously t

recorded. This trend contianes, thus the differential temperatura la close to oma critarion, indicating loss e6 stable nat=r=1 circulation.

(2) Imop "A" parameters emperience frequent oseillations on a regular basis.

(3) An apparent correlation exists between the water level in the OrSG and thermal driving head in RCS and therefore, it has an effect on loop flow and differential temperatures.

I (4) It appears uncertain as to what was actual steam generator level ("A" and "B") la the six soothe prior to the subject i

l event.

i In light of the above, we request that an engineering evaluation be done to determine the effect on RCS loop flow and differential temp-erature and the available head for natural circulation with changing water level in the OTSG "A".

Assimiptions and -=1e=1=tions used in the. evaluation should be provided. In addition, please provide best estimate of "A" and "B" OTSG actual level for the period six months prior to the subject events to support your evaluation. Your concla-sions should imelude the necessity to revise the loss of stable natural circulatian criteria (per Biergency Procedure, EF-34).

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SURNAME >

OATED NRC Form 318 (2 76) NRCM 02040 c u.s. Go V E RNMEN T P RIN TING OP MC Er 9,76_634_733 3[

7912040

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l Metropolitan Edison Compary 2

J. J. Colits, Manager Plant higineering R. F. Wilaan, DLrector TMI-2 Becovery, Acting I. R. Finfzoek, Jr.

L W. Conrad G. F. Tmwbridas, seguire J. & Liebezzan, F.arydn Ms. Mary V. Southard, Chairperson, Citizens for a Safe Envi4wat, (without encl) becw/ enc 1:

IE Mail & Files (For Appropriate Distribution)

Central Fi'.es Public Document Ibom (PDR)

Local Public Document Ibom (IPDR) (!EIC)

Nuclear Safety Infomation Center Technical Infomation Center (TIC)

RE:I Reading Ibom Director, Region IV (Report Only) l Commonwealth of Pennsylvania j

Ms. Mary V. Southard, Chairperson, Citizens for a Safe Environment i

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o*Te m NRC Form 318 (2-76) NRCM 02040 tr u.s. oov ERNMEN T PRIN TING OF FIC E: 89"6-434-702

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