ML20246M452

Provides Results of Pressurizer Surge Line Visual Insp Work Performed During Outage & Plans for Monitoring & Collection, Per NRC Bulletin 88-11.W/one Oversize Drawing

ML20246M452
Person / Time
Site:	Point Beach
Issue date:	05/08/1989
From:	Fay C WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20246M458	List: ML20246M452 ML20260A556
References
CON-NRC-89-054, CON-NRC-89-54 IEB-88-011, IEB-88-11, VPNPD-89-269, NUDOCS 8905190144
Download: ML20246M452 (4)

Text

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4 Wisconsin Electnc POWER COMPANY 231 W Michigan, PO. Box 2046. Milwaukee?M 53201 (414)221-2345 VPNPD-89-269 NRC-89-054 May 8, 1989 U. S. NUCLEAR REGULATORY COMMISSION Document Control Desk Mail Station Pl-137 Washington, D.C. 20555 Gentlemen:

DOCKET 50-266 PRESSURIZER SURGE LINE VISUAL INSPECTION RESULTS POINT BEACH NUCLEAR PLANT - UNIT 1 s

We have completed our inspection of the Point Beach Nuclear Plant - Unit 1 pressurizer surge line in accordance with the requirements of IE Bulletin 88-11. This letter provides the results of the inspection, work performed during the outage, and our plans for operational data monitoring and collection.

The pressurizer surge line routing and support arrangement for Unit 1 are shown on isometric drawing P-145 attached (Attachment 1). The system is hung by three spring hangers, RC-1 through 3. Additionally the line is restrained for pipe whip by restraints R-1 through 5. A VT-3 inspection was performed on April 3, 1989 with the system in a hot condition (approximately 500 F) and on April 28, 1989 with the system at ambient l conditions. The following were observed:

1. During the hot inspection, it was observed that the surge line pipe collar (Reference Attachment 2, Drawing M-400, Sh. 5, l Detail 17) was in apparent contact with the pipe whip restraint R-4 at the 270 point. No visual deformation of the restraint structure, collar, lugs, or piping was observed.

2. During the cold inspection, two small cracks were observed in the fillet welds between the pipe collar and the top of the lug (position O ) at the north end of whip restraint R-5. One crack, approximately 3/8" long and 3/16" deep, was located on the west side of the lug. The other crack was located on the east side of the lug and was approximately 1/8" long and 1/8" deep. Both indications were ground out and verified as 8905190144 890508 A0Y7 PDR ADOCK05000g6 at p

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Document Control Desk May 8, 1989

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l removed by liquid penetrant examination. The design of these 4 attachment welds was specified as a 1/4" fillet for 1" in length (see Attachment 2). However, the inspection revealed that a 1/4" fillet weld was placed along the full length of the' lug to the pipe collar joint (8"). The integrity of the joint has not been compromised by the removal of these indications and the restraints were operable with the cracks considering the excess amount of weld material.

3. The piping and all other support installations did not show any discernable distress or damage.

In order to eliminate any potential contact between the surge line collars and the restraining hardware due to thermal expansion during future operating cycles, we have removed the portion of the collars at locations R-4 and R-5 on the side opposite the steam generator (SG) during the outage. This is acceptable since, according to the original design, only the side facing the SG is necessary to protect the SG from pipe whip. After removal of the collar pieces, a visual examination of the collar and support hardware was performed to see if any discernable galling existed on either surface, which would confirm significant contact between the surfaces. No visual evidence of galling was present. Based on this physical data, it can be concluded that any contact which may have occurred from thermal expansion was incidental and, therefore, any loads from such contact transmitted to the lug / pipe attachment were probably insignificant.

Measurements of the actual surge line displacements at locations R-4 and R-5 will be made during plant heatup to confirm whether or not actual collar / restraint contact has occurred since original plant construction at either or both of these locations. If the measurements confirm that significant contact has occurred,

- appropriate local stress and fatigue evaluations will be performed and incorporated into the stress and fatigue analyses required to respond to IE Bulletin 88-11.

Additionally, during the outage we installed twenty-three (23) thermocouple at five (5) locations on the surge line. These locations are identified on Attachment 1. We will monitor and collect temperature data during typical startup and steady state power operation conditions to facilitate either generic or plant specific qualification of the surge line for all conditions including thermal stratification and striping.

l

. Document Control Desk

(. :' May-8',1989 ,

!: Page.3 This, completes Action 1.a requirements of IEB 88-11 for Point Beach Unit 1. If you have any questions or comments, please contact us.

i Very truly yours,

<i

/'  ;

'C. W. Fay [

-Vice. President

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