Method and apparatus for manipulating equipment inside a steam generator

A method of sludge removal from a top of a tube sheet surface in a tubular steam generator having a plurality of heat exchange tubes extending from the tube sheet surface in rows to form a tube bundle with a circumferential annulus extending around the heat exchange tubes on a periphery of the tube bundle and a plurality of entry handholes allowing access to a no-tube lane extending over the tube sheet surface or to the circumferential annulus, comprising the steps of:

• opening at least one handhole on an outer surface of a shell of the steam generator, allowing access to the no-tube lane and/or to the circumferential annulus;
• introducing at least one moveable sludge suction apparatus within the no-tube lane and/or the circumferential annulus, said apparatus includes a suction head with at least one vacuum inlet;
• moving the moveable sludge suction apparatus among the heat exchange tubes over the surface of the tube sheet;
• sludge vacuuming of the top of tube sheet surface with the moveable sludge suction apparatus;
• and
• adding a fluid, comprising water, through at least one of the plurality of handholes in a lower part of the shell just above the tube sheet, to the top of the tube sheet surface while sludge vacuuming the tube sheet with the moveable sludge suction apparatus, within the tube lane, to maintain a substantially constant water level cover over substantially the entire tube sheet as the vacuum draws off the loose sludge and the water, to prevent the sludge from drying out;
• wherein the moveable sludge suction apparatus has a wand with a bend radius capable of traveling around an approximate ninety degree turn or bend, wherein the wand is at least in part, slidably supported in or on the sludge suction apparatus and extends out of the sludge suction apparatus a distance substantially parallel to the tube sheet, at least as long as a distance the tool is to be inserted into the tube lane, with one end portion of the wand extending along the annulus and connected to a robotic vehicle and another end portion of the wand, bent the approximate ninety degrees, carrying the suction head, wherein the step of extending the suction head comprises moving the robotic vehicle toward the sludge suction apparatus.

A remotely controlled robotic system for manipulating a tool over a tube sheet with a tube bundle within a secondary side of a tube and shell steam generator, the tube bundle having a plurality of heat exchange tubes extending from the tube sheet in rows with an annulus extending around the heat exchange tubes on a periphery of the tube bundle, between the tubes and a shell which surrounds the tube bundle, comprising:

• a first robotic vehicle sized to ride in and at least partially around the annulus;
• a wand is, at least in part, supported on and extendable from the first robotic vehicle substantially through a lane between two rows of heat exchange tubes and retractable through the first robotic vehicle, out of the tube lane, the tool being supported from a first end portion of the wand that extends from the first robotic vehicle through the lane between two rows of heat exchange tubes;
• a controller for controlling the extension of the wand and operation of the tool during the extension;
• and
• wherein the wand has a bend radius capable of traveling around an approximate ninety degree turn or bend, wherein the wand is at least in part, slidably supported in or on the first robotic vehicle and extends out of the first robotic vehicle, through the annulus, a distance substantially parallel to the tube sheet, at least as long as a distance the tool is to be inserted into the lane between the two rows of heat exchange tubes, with a second end portion of the wand extending along the annulus being connected to a second robotic vehicle and the first end portion of the wand, bent the approximate ninety degrees, supporting the tool, the second robotic vehicle being sized to travel in the annulus independent of the first robotic vehicle to vary the length of the wand extending between the two rows of heat exchange tubes.