ML17272A334

Rept on Defective Pipe Whip Restraint Brackets Supporting Residual Heat Removal,Reactor Feedwater & Main Steam Piping Sys Inside Containment.Defects:Slag Inclusions & Porosity. Twenty Brackets Refabricated & 14 Repaired

ML17272A334
Person / Time
Site:	Columbia
Issue date:	03/13/1979
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A333	List: ML17272A332 ML17272A334
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 7903210095
Download: ML17272A334 (1)

Text

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~ 4 WPPSS NUCLEAR PROJECT NO. 2 Reportable Deficiency and Corrective Action For Defective Welds Found In Pipe Whip Restraint Brackets WASHINGTON PUBLIC POWER SUPPLY SYSTEM DOCKET No. 50-397 License No. CPPR-93 Nature of Deficienc Pipe whip'estraint brackets used in supporting the Residual Heat Removal (RHR), Reactor Feed Water {RFW) and the Main Steam Piping System, inside containment, were found to have numerous weld defects in the electroslag welds. These defects consisted of slag inclusions and porosity, and have been documented on IR-78-1192 (215), NCR 215-03410 and PED 215-CS-0117. The weld deficiencies could only be a result of a

-departure 'from 'the approved electroslag weld procedure.

Safet Im lications If the welds were left uncorrected and were subjected to loads, as a result of a pipe rupture, the weld defects could propogate causing the welds to crack and the pipe whip support brackets to fail. The failure of the pipe whip supports would therefore not restrain pipe whip which could cause damage to surrounding components and equipment, thus ad-versely affecting the safety of the Nuclear Power Plant.

I Corrective Action Taken Forty-five (45) pipe whip restraint brackets were fabricated using the Leckenby electroslag process. These bracket welds were evaluated using the radiographic and/or ultrasonic technique. Twenty (20) brackets were completely refabricated, fourteen (14) which obtained lesser defects were repaired and eleven (11) were found to be acceptable. zt this time all brackets have been installed in the plant.

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