ML20080S549

Interim Deficiency Rept,Item 110 Re Linear Cracking in side-to-back Bends in Struts Mfg by Unistrut.Initially Reported on 840104.Test Results Provided by Unistrut Under Review.Corrective Actions Will Be Sent When Info Available

ML20080S549
Person / Time
Site:	Fermi
Issue date:	02/17/1984
From:	Wells D DETROIT EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
110, EF2-66495, NUDOCS 8402290157
Download: ML20080S549 (2)

Text

., - 3 Donald A. Wells gegg Awance E $Nok'l$$$aUs*22e February 17, 1984 s jats)2n-m m EF2-66495 Mr. James G. Keppler, Regional Administrator Region III U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Report of 10CFR50.55(e) Item on Linear Cracking in Unistrut

(#110)

Dear Mr. Keppler:

On January 4, 1984, Detroit Edison's Mr. W. R. Wingfield, Quality Engineer - Construction Quality Assurance telephoned Mr. R. C. Knop of NRC Region III to report on linear cracking in Unistrut at the Fermi 2 site.

Linear (longitudinal) cracks in the side-to-back bends of Unistrut Catalog No. P1000 Strut were identified during an installation inspection by PQA personnel. Further investigation by PQA personnel originally narrowed the scope of the problem to P1000 Strut of Coil Lot Number 2Z6450. However, subsequent reinspection by PQA of all unistrut in stock identified less significant similar indications in other coil lot numbers. The use of this lot of material at Fermi 2 appears to be limited to electrical raceway supports.

Cracking appears to have originated during forming of the material due to a high hardness of the particular heat. The crecks found, in some instances, penetrate 50 percent of the wall thickness. Cracking has been subsequently identified in all bends of strut formed from the defective Coil Lot Number.

l Longitudinal cracks could severaly reduce the strength of the strut cross-rection at points of high stress concentration during a seismic event. This could result in premature failure of the strut and could compromise . the attached safety-related plant component (e.g., conduit, l cable tray).

Detroit Edison Project Field Engineering has supplied samples from the 2Z6450 lot to Unistrut Building Systems for determination of actual strut structural properties under various load configurations.

Unistrut Building Systems has provided an engineering test report detailing structural properties for the deficient material lot samples. Unistrut Building System's test report indicates structural property test values for the samples exceed catalog requirements with no evidence of crack area proliferation. Detroit Edison Project Field )

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Mr. James G. Keppler, Regional Administrator February 17, 1984 EF2-66495 Page 2 Engineering. is currently evaluating the test results. Corrective action will be defined based on the results of the evaluation by Detroit Edison Project Field Engineering.

Another_ report on this item, either interim or final, will be sent when further~information is.available. If you have questions

.concerning this matter, please contact Mr. G. M. Trahey, Assistant Director - Project Quality Assurance.

Very truly yo a l *

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cc: Mr. Richard DeYoung, Director j' jWM Office of Inspection and Enforcement U. S. N uclear Regulatory Commission Washington, D. C. 20555 Mr. Paul Byron, Senior Resident Inspector U. S. Nuclear Regulatory Commission 6450 North Dixie . Highway Newport, Michigan 48166 d

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