ML17272A936

Interim Deficiency Rept Re Carbon Steel Small Diameter Pipe Installed W/Less than Min Allowable Wall Thickness. Caused by Contractor Utilizing Grinders to Remove Oxide & Mill Scale from Pipe in Preparation for Welding

ML17272A936
Person / Time
Site:	Columbia
Issue date:	04/21/1980
From:	WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:
Shared Package
ML17272A935	List: ML17272A934 ML17272A936
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8004280476
Download: ML17272A936 (1)

Text

WPPSS NUCL'EAR PROJECT NO. 2 REPORTABLE DEFICIENCY AND CORRECTIVE ACTION FOR DESIGN OF SMALL DIAMETER.(2" and under) PIPE WITH WAL'L THICKNESS LESS THAN SPECIFIED REQUIREMENTS WASHINGTON PUBLIC POWER SUPPLY SYSTEM DOCKET NO. 50-397 LICENSE NO. CPPR-93 DESCRIPTION OF DEFICIENCY Carbon steel small diameter pipe has been installed with less than the minimum allowable wall thickness specified for the applicable pipe schedule. This condition occurred when the Mechanical Installation Contractor (215) utilized grinders and other power tools to remove oxide-and mill scale, from the pipe in preparation for welding. The wall thinning is localized at the ends of the pipe at socket. weld joint.

SAFETY SIGNIFICANCE Failure of the carbon steel small bore diameter pipe could result in the failure of safety related system components, adversely affecting the s a fe opera ti on of the pl ant.

CORRECTIVE ACTION Contract 215 has issued instructions to their personnel to use wire brushes instead of grinders when preparing pipe for welding and their work procedures are being revised accordingly.

A technical evaluation'of the condition identified via Nonconformance Report No. 215-05196 is being performed by the A/E. It is anticipated that wall thickness measurements and design evaluation will be performed for the affected high pressure systems. Any socket weld connections which do not satisfy the minimum design wall thickness requirements will be corrected.