ML19260D362

LER 80-018/01T-0:on 800123,during Review of IE Bulletin 79-14,15 Points on Regenerative Heat Exchanger Discharge Lines Were Identified as Overstressed & Two Nodes Faulted Allowable Limits.Caused by Incorrect Weights

ML19260D362
Person / Time
Site:	North Anna
Issue date:	02/06/1980
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML19260D358	List: ML19260D357 ML19260D362
References
IEB-79-14, LER-80-018-01T, LER-80-18-1T, NUDOCS 8002080566
Download: ML19260D362 (1)

Text

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1. H t,0 61 DOCKE T NUNMEH bd th7 EVENT DA's 14 REPOR T D ATE EV ENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l During the review for IE Bulle tin 79-14, Stone & Webs 3r identified 15 noinen nr nndo n !

o a l on regenerative heat exchanger discharge lines 3"-CH-1-1502-01 and 2"-CH-6 8- 15 0 2-01 I o 4 l which are stressed over nordal upset allowable and 2 nodes whose calculated strasa o s [ exceeds faulted allowable. After comparing the code allowable of three overstressed I O 6 l points to the actual physical properties of the pipine, the worst case stress ms I o 7 determined to be below faulted allowable but still slightiv above er'ercency allowable 1 0 a i and the other point, less than the normal upset allowable. %e public henith nnd sn fe tI 87 7 8 9 Were not a,rfgc,tedbytgisevgny Reportable pursuant to T.S Q .9.1. g CODE '- ODE SU8 CODE COYPONENT CODE SU9 CODE SUBCODE 7

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3/ 40 42 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h i o l Le cause of the overstressed condition is that an incorrect valve operator weinht for I

, ;,, ;HCV-1310 was used in the pipe stress design calculations. A snubber will be desicned I to provide axial support to the hanging valve manifold. His snubber will be added to I

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Virginia Electric:and Power Conpany North Anna Power Station, Unit #1 Attachnent: Page 1 of 1 Doc ke t No. 50-338 Re po rt No. LER 80-18/01T-0 Description of Event On January 23, 1980, during the review for IE Bulletin 79-14, Stone & k'ebster discovered that nornal charging line 3"-CH-1-1502-Q1 and auxiliary spray line 2"-CH-68-1502-Q1 both have a number of points or nodes along their length which are overstressed. 15 points which are stressed above the normal upset allowable and 2 points whiich exceed the faulted allowable were identified.

Three of the overrtres' sed points, including the two worst cases , were analyzed by comparing the code allowable with actual physical properties by us2 of nill certificaticns for the particular pipe sections. Results revealed that the stress on nodes 265 and 270 is less than the faul ted allowable but still exceeds the emergency allowable by a slight margin.

Also, the stress on node 10 was found to be below the normal upset allowable.

The code allowable for the remaining overstressed points have not yet been corrected by use of mill certs. If the results are sinilar to those of the previous discussion, all, or the majority, should be found to be within acceptable stress linits.

Probable Consequences of Event Because the stress on nodes 265 and 270 ic greater than the energency allowable, local deformation of the piping could result from the ef fects of a seisnic disturbance. Powever, since the stress does not exceed the faulted allowable, no actual pipe separation should occur. The health and safe ty of the general public were not af fected by this event. There are no generic implications associated with this occurrence.

Cause of Event The overstressed ccndition exists because an incorrect valve operator weight for HCV-1310 was used in the pipe stress design calculations.

This changed the total weight of valve HCV-1310 fron 175 lbs. to 335 lbs.

Inmediate Corrective Action A snubber is being designed to provide axial support to the valve manifold.

Scheduled Corrective Action During the next outage of suf ficient duration, the snubber will be added to the line in the area of valve HCV-1310.

Actions Taken to Prevent Recurrence No further actions are required.