ML19312D482

LER 80-034/01T-0:on 800307,S&W Discovered That Several Class 2 Lines in Low & High Head Safety Injection Sys Were Not Stress Analyzed for Fluid Temp.Caused by Deficiency in Piping Sys Stress Analysis

ML19312D482
Person / Time
Site:	North Anna
Issue date:	03/21/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19312D477	List: ML19312D476 ML19312D480 ML19312D482
References
LER-80-034-01T, LER-80-34-1T, NUDOCS 8003240473
Download: ML19312D482 (2)

Text

CRC FORM 366 U. S. NUCLEAR REIULATGY COMMISSION

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7 -8 60 61 DOCKET NUMB ER EVENT OESCRIPTION AND PROBABLE CONSEQUENCES h 10121 - l On March 7, 1980, Stone & Webster discovered that several Class II (02) lines in the 1 0 3 'l low and high head safety injection system have not been stress analyzed for fluid temp}-

O 4 l eratures which could be expected during the injectior; phase of the Emergency Core Cooll-O s l ing System. The health and safety of the general public were not affected by this l 0 s l occurrence. Reportable pursuant to T.S. 6.9.1.8.h. l 0 7 l I 101811 I E CODE S BC E COMPONENT CODE SUS O'E S E 7

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44 47 CAUSE OESCRIPTION AND CORRECTIVE ACTIONS g l The event occurred as a result of a deficiency in the piping system stress analysis. I i i l The af fected piping is being re-evaluated to determine what modifications, if any. to 1

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Virginia Electric and ' Power Company

. North Anna Power Station, Unit #1 Attachment, Page 1 of 1 Docket No. 50-338 Report No. LER 80-034/01T-0 Description of Eve-t On March 7,1980, Stone & Webster discovered that several Class II (Q2) lines in the low and high head safety injection system have not been utress analyzed for fluid temperatures below 70*F. The subject lines transport water from the Refueling Water Storage Tank to the Reactor

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Coolant System cold legs during the injection phase of the Emergency Core Cooling System, and, as such, can be exposed to fluid temperatures in the 40-50*F range. Th'c resulting pipe wall temperatures below 70*F could create limits on equipment and pipe supports which have not been previously analyzed.

Probable Consequences of Occurrence With piping handling water temperatures less than 70*F, pipe stresses and -

support loading could exceed design allowables and possibly prevent the Emergency Core Cooling System from performing its intended function during a postulated accident condition. The health and safety of the general public were not affected by this event. The low and high head safety injection lines for Unit 2 were also not analyzed for fluid temperatures below 70*F and are therefore similarly affected.

Cause of Event The event occurred as a result of a deficiency on the part of the Architect Engineer in the stress analysis of the piping system.

Immediate Corrective Action The affected piping is presently being re-analyzed to determine if any modifications to the installed restraint arrangements are required as a result of the deficiency in the piping system stress analysis.

Scheduled Corrective Action Pending the completion of the current safety injection piping temperature review, pipe support modifications, _ if required, will be made as determined necessary.

Action Taken to Prevent Reccurrence No further actions are required.

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