Steam Generator Water Lancing

Abstract

The tubesheet and tube support plate deposits in CANPU steam generators are notable for their hardness. Also notable is the wide variety of steam generators access situations. Because of the sludge hardness and the difficulty of the access, traditional water lancing processes which directed jets from the central tube free lane or from the periphery of the bundle have proven unsuitable. This has led to the need for some very unique intertube water lancing devices which could direct powerful waterjets directly onto the deposits. This type of process was applied to the lipper broached plates of the Bruce A steam generators which had become severely blocked. It has since been applied to various other steam generator situations. This paper describes the flexlance equipment development, qualification, and performance in the various CANDU applications.