ML20141N860

Interim Deficiency Rept 86-01 Re Discrepant Spot Welds on Cable Tray Hangers Made of P1004A Unistrut Matl.Initially Reported on 860210.Walkdown of Hangers Completed & All Discrepant Welds Recorded

ML20141N860
Person / Time
Site:	Byron
Issue date:	03/12/1986
From:	Ainger K COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
1406K, 86-01, 86-1, NUDOCS 8603180215
Download: ML20141N860 (4)

Text

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.- Wd Commonwealth Edison One First National Prza. Chicago, lihnois Address Reply to: Post Omce Box 767 Chicago, Illinois 60690 March 12, 1986 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, IL 60137

Subject:

Byron Station Unit 2 10 CFR 50.55(e) Thirty-Day Report Cable Tray Hanger Spot Welds NRC Docket No. 50-455 Reference (a): March 6, 1986 letter from A. D. Miosi to J. G. Keppler

Dear Mr. Keppler:

On February 10, 1986, Commonwealth Edison notified Mr. R. Lerch of your office of a potential deficiency reportable pursuant to 10 CFR 50.55(e) regarding spot welds on cable tray hanger material at Byron Station Unit 2.

For tracking purposes, this potential deficiency has been assigned Number 86-01. This letter provides information to fulfill the thirty-day reporting requirement and is considered an interim report.

Description of Deficiency Reference (a) described a deficiency identified at Braidwood Station concerning P1004A Unistrut material used for fabrication of cable tray and conduit hangers at Byron and Braidwood Stations. The P1004A member is a built-up section consisting of two single P1000 channels spaced back-to-back and joined by two side plates with four rows of spot welds at 3 inches on center. The conditions reported consist of one or more discrepant spot welds on cable tray hangers.

Analysis of Safety Implications The safety significance of the discrepant spot welds has not been fully assessed. Scoping analysis to date for cable tray hangers with significant discrepant spot welds in heavily loaded applications indicates that there is no safety significance. This preliminary conclusion will be verified by an engineering evaluation.

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.' O J. G. Keppler March 12, 1986 Corrective Action Taken A walkdown of all cable tray hangers comprised of P1004A Unistrut members has been completed for Byron Unit 2. The members were inspected using the same inspection technique at Braidwood Station and all discrepant welds were recorded. The results of this walkdown are summarized in the attached table. The number of henger members in which discrepent welds were found and the total number of hanger members inspected are shown for each control number. Only 13 members of 233 inspected were found to have discrepent welds. Commonwealth Edison Company Nonconformance Report F-1045 has been initiated to track this concern.

The scope of the suspect P1004A material is limited and has been established in reference (a). The suspect material appears to have been utilised primarily for cable tray hangers at Braidwood Unit 2. The results of the Byron Unit 2 walkdown support this conclusion.

An engineering evaluation will be completed to assess hangers with discrepant welds and other hangers with suspect control numbers not identified with discrepant welds. An evaluation will also be done to assess the adequacy of adjacent intact spot welds.

It is apparent that, in addition to the suspect material, occasional discrepent spot welds exist. Unistrut expects that occasional discrepant spot welds may not be detected by their Quality Assurance program. An engineering evaluation will be completed to assess this condition on a generic basis.

In summary, the results of the Unistrut P1004A investigation demonstrate that:

1. The scope of the issue is limited to 580 feet of discrepant material which was inadvertently shipped to Systems Control Corporation and used to fabricate cable tray hangers. Walkdown data supplemented by vendor records leads to the conclusion that these hangers are primarily in Braidwood Unit 2.

2. Occasional discrepant spot welds are expected by Unistrut for nonsuspect material. An engineering evaluation will be performed which should accept this condition on a generic basis.

3. An engineering evaluation will be performed for all hangers remaining with suspect control numbers. The control numbers shown in the attached table with an 8 prefix are considered suspect.

0 J. G. Keppler March 12, 1986 A final report will be submitted after completion of the engineering evaluations discussed above.

Please direct any questions you may have regarding this matter to this office.

Very truly yours, K. A. Ainger Nuclear Licensing Administrator la Attachment cc: Byron Resident Inspector Director of Inspection and Enforcement 1406K

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UNISTRUT P1004A WALKDOWN >

BYRON 2 CABLE TRAY SUPPORTS CONTROL NUMBER HANGER MEMBERS NUMBERS DISCREPANT TOTAL INSPECTED 7P3167 1 47 7P3351 3 48 8E7828 5 15 8N7791 3 41 8N7792 1 44 OTHERS 0 38 TOTAL 13 233 1

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