Patent ID: 8238510

Claim:
A method of sludge lancing a tube bundle in a tubular steam generator having a plurality of entry handholes allowing access to a center tube lane, the tube bundle having a hot leg side and a cold leg side separated by the center tube lane which lane at its mid point intersects a central cross row of tubes and has a central stay rod, comprising the steps of: 1) opening at least one handhole opening into a center tube lane; 2) introducing at least one moveable sludge lance, fitted with nozzle jets and having dual lance heads, separated a distance greater than the diameter of the central stay rod, into the center tube lane moving on a monorail which provides a rigid platform for the dual lance heads, and a rolling kickstand which movement provides a forward support for the monorail; and 3) sludge lancing the tube bundle with cleaning fluid passing to the moveable sludge lance, so that the dual lance heads traverse the central tube lane to extend beyond the central stay rod allowing continuous and complete cleaning of the tube bundle, where a gearbox assembly passes the sludge lance from one end of the monorail to the other, and the dual lance heads, having cantilevered reaction bars and lance barrel assemblies with jet nozzles all parallel to the monorail axis, are attached to a monorail carriage combination which carriage traverses the monorail axis by means of monorail rails parallel to the monorail, and a jaw means, located forward of the kickstand, registers the center stay rod to center the monorail.