Abstract: A lance tube formed of a tubular conduit having an inner end to be joined to a source of pressurized fluid, a closed distal end, a continuous wall between the inner and distal ends, and a plurality of tube discharge openings in the continuous wall; and a plurality of axially positioned fluid direction tubes within the conduit, each tube having a straight intake section generally axially aligned with the conduit and having an intake opening toward the conduit inner end, a straight discharge section having a discharge opening at one of the discharge openings in the conduit wall, and an intermediate curved section joining the intake and discharge sections, whereby fluid entering the conduit will be directed through the fluid direction conduits, and will be discharged in laminar flow from the discharge openings.

Abstract: A steam generator lancing system for cleaning tubes and tubesheets of a steam generator. The lancing system includes a nozzle block including at least one nozzle adapted for fluid communication with a high pressure hose. The lancing system also includes a support assembly including a carrier for transporting the nozzle block through the steam generator and a control system operative to selectively position the nozzle with respect to the tubes and tubesheets in the steam generator. Finally, in the preferred embodiment, the lancing system includes a rocker assembly operable to rotate the nozzle about a rocker axis to improve cleaning efficiency.

Abstract: An apparatus for removing sludge from the tubes and tubesheet of a steam generator. A support structure is adapted to be mounted at an access port of a steam generator. A lance tube extends from the support structure into the steam generator. A spool attached to a high pressure hose is received in the lance tube. A pinch roller assembly mounted on the support structure is used to move the cylinder through the lance tube. High pressure water flows through slots drilled in the spool and out holes in the lance tube against the tubes and tubesheet. A rocker motor causes back and forth rotation or rocking of the lance tube to create a sweeping action. The lance tube may also be adjusted axially to insure that the water streams are directed to the tube lanes.

Abstract: Sludge-removing fluid lances are moved simultaneously toward the center of a tube bundle in a steam generator through diametrically opposite lance ports. Fluid-blocking suction dams are placed in the peripheral lane of the steam generator at diametrically opposite inspection ports from which fluid-entrained sludge is removed. All four of the ports are spaced apart by 90.degree.. Fluid-entrained sludge is blocked on the opposite sides of both suction dams, thereby preventing redeposition of sludge in previously cleaned areas of the tube sheet of the generator. The fluid flow rates of the lances are controlled to be equal to each other, and the rate of removal of the fluid-entrained sludge through each suction dam is controlled to be the same as the fluid flow rate of each lance. A separate flushing stream in the peripheral lane is not required.

Abstract: A method and apparatus for removing from the tube sheet and transfer tubes of a nuclear steam generator sludge deposits which occur from the use of all volatile treatment water chemistry. A continuously activated suction apparatus maintains at a low level the water/sludge inventory on the tube sheet. A high pressure first water lance is oscillated and stepped inwardly along the central tube lane of the generator to dislodge the sludge from the tube plate and heat exchange tubes. After this lance has been stepped inwardly to a predetermined position, a low pressure second water lance is activated and periodically advanced to a position just short of the first lance and functions both to dislodge sludge and to form a water barrier which prevents redeposition of sludge in the clean area.