ML19241A724

Followup Rept to LER 79-083/01T-0:high Energy Line Breaks Inside Containment Could Cause Heatup of Steam Generator Ref Leg,Causing Level Indications Higher than Actually Exist.Caused by Incomplete Westinghouse Analysis

ML19241A724
Person / Time
Site:	North Anna
Issue date:	06/22/1979
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
LER-79-083-01T-01, LER-79-83-1T-1, NUDOCS 7907090329
Download: ML19241A724 (1)

Text

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' / . ; 7; 3 J M122 P l: lg Virginia Electric and Power Corpany Nortn Anna Pcwer Staticn, Unit 1 Eccket No. 50-338 24 Hcur Reportable Event Written Follcs-Up Event:

Accuracy of Stean Secerator Level Indicatica follcbing a high energy line rupture LER/R0 79-C33/0lT-0 Westinghcuse infored Vepco that high energy line breaks inside the contair. rent can result in the heatup of the stean generator level reference leg causing level indication to te higher than actually exists, thus delaying the protectica signals that are initiated prir.:arily by a lc*-lc,s Stean Generator level.

The cause of this discrepancy is that the heating of the steEn generator-level reference legs follcwing a nain feedline break was not taken into account during the original Westinghcuse analysis.

Westinghcuse has provided the necessary data to co pensate for the reference leg heatup effects follcaing a high energy line rupture.

There is no effect en the Unit for centinued operations as a result of this discrepancy because if a nain feedline rupture stauld cccur Safety Injecticn, reactor trip and auxiliary feedwater actuation will te initiated by Ccataire ent Hf Pressure before any significant error in stean Senerator level indicatien could cccur dt.e to reference leg heatup. The analysis is sinilar to a nain steanline rupture hich is described in Cc.r.ent 6.105 of the FSAR.

The unit is presently operating in Mcde 1.

All cperating perst.or.e1 shall te =ade aware of this discrepancy.

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