ML20064F880

/01T-0 on 781116:Svc Water & Component Cooling Piping & Pipe Supports Not Analyzed for Thermal & Seismic Stresses.Design Personnel Utilized Wrong Svc Water Temps for Stress Analysis.Present Analysis Shows Adequate Support

ML20064F880
Person / Time
Site:	North Anna
Issue date:	11/29/1978
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20064F874	List: ML20064F872 ML20064F880
References
LER-78-124-01T, LER-78-124-1T, NUDOCS 7812050226
Download: ML20064F880 (2)

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8 60 61 DOCKET NUMBER 68 EVENT D ATE EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h

[Olal l During steady-state, 96% power operation. it was discovered that Service Water and l IO l3 l 1 Component Cooling piping and pipe ' supports had not been analyzed for thermal and l lo lol l seismic stresses for Service Water temperatures above 95 8F. Also, Service Water l

!olsl l Pi Pe supports had not been analyzed for Service Water temperatures below 70*F. l l O ls l l Preliminary analysis indicates Service Water temperatures could exceed 95'F during l l 0 l 7 l l LOCA conditions. Also, the present Service Water temperature is below 70*F. Report-l W aj i able pursuant to T.S. 6.9.1.8.i. 80 l

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] g 42 l43Al @ l 5l 4l 2l 0lg 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h lijoll During the design stages of North Anna Unit I design personnel utilized the wrong l l3 gil l Service Water temperatures for piping and pipe support stress analysis. Engineering I

, g l is presently analyzing the problem for required corrective action. Analysis completed l

[(, , p l since the discovery of this problem has determined that all Service Water system l 5,g4; l supports are adequate for service water temperatures from 45'F to 95'F. l 7 8 9 80 ST *$  % POWER OTHER STATUS SO R =

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.3 8 9 10 68 69 80 & l W. R. Cartwright 703-894-5151 o NAME OF PREPARER PHONE: $

".' *beginiaElectricandPowarCompany North Anna Powar Stetion, Unit No.1

Attachment:

Psg's 1 of I Docket No.: 50-338 Report No.: LER 78-124/01T-0 Description of Event: -

r During steady-state, 96% power operation, Stone & Webster Engineering .

Corporation informed us that all Service Water System and Component Cooling  ;

piping and pipe supports had been analyzed for combined seismic and thermal ,

stresses assuming a maximum Service Water temperature of 95*F. We were also informed that Service Water System pipe supports had not been analyzed for Service Water temperatures below 70*F. .

Presently, the Technical Specifications limits the Service Water temperature to a maximum of 95*F and preliminary analysis indicates that F

for Service Water temperatures at or near 95*F, post LOCA conditions would cause the Service Water temperature to exceed 95*F. t Probable Consequences of Occurrence: ,

[ This event affects approximately 674 pipe supports. The design l loading for each hanger at 95'F Service Water temperature was compared to the anticipated loading at 45*F, and all but 30 hangers were found I 1 capable of withstanding loading to 45'F. Subsequently, the 30 outstand-ing supports were re-analyzed and found acceptable to 45*F.

I Presently, the' Service Water. temperature is approximately 60*F, and based on preliminary analysis indicating a 12*F Service Water temperature l i

rise during post LOCA conditions, the Service Water temperature will not i exceed 95*F.

Hence, all piping and pipe supports have been found capable of meeting design loading for Service Water temperatures between 45'F and 95'F, and  ;

this occurrence had no ef fect on the safety of operating personnel or the l public. Analysis of the Component Cooling System is still in progress, t

Cause:

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During the design stages of North Anna Unit 1, S & W design personnel assumed incorrect Service Water temperature for the piping and pipe support .

stress analysis.

Immediate Corrective Action:

Operations adjusted Service Water temperatures as necessary to keep  ;

them at design conditions.

Scheduled Corrective Action:

An engineering evaluation of this problem is being undertaken to determine the corrective action required. l Action to Prevent Recurrence: l No further action required. .

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