Abstract: A method of removing a metal plug from a conduit includes the steps of simultaneously applying a static pull force and repetitive impulses to the plug. The method is particularly suited to removing a plug from a heat exchanger tube in a nuclear powered steam generator. A tool for practicing the method on such plugs includes a first hydraulic actuator for first moving an expansion member out of engagement with an interior plug wall, a second hydraulic actuator capable of attachment to the plug for applying a static pull force to the plug, and an arrangement connecting an air impact tool to the second hydraulic actuator for applying, simultaneously with the static force, high-frequency impulses to the plug entirely through solid members.

Abstract: A tool for removing a metal plug from a tube with repeated pulling impulses includes a pneumatic cylinder defining an interior, cylindrical chamber. A distal end surface of the cylinder defines an anvil. A cylindrical slug, or hammer, is sealingly slidable within the chamber in response to a pressure difference above and below the hammer within the chamber. The cylinder is rigidly connected to the plug so as to hang therefrom, the weight of the cylinder providing a static pull force working in conjunction with the pulling impulses. A pulling impulse is provided by first raising the hammer above the anvil by pneumatically creating a first pressure difference wherein the pressure below the hammer is greater than the pressure above the hammer, then creating a second pressure difference wherein the pressure below the hammer is no greater than the pressure above the hammer in order to drive the hammer against the anvil at speed.

Abstract: A method of removing a metal plug from a conduit includes the steps of simultaneously applying a static pull force and repetitive impulses to the plug. The method is particularly suited to removing a plug from a heat exchanger tube in a nuclear powered steam generator. A tool for practicing the method on such plugs includes a first hydraulic actuator for first moving an expansion member out of engagement with an interior plug wall, a second hydraulic actuator capable of attachment to the plug for applying a static pull force to the plug, and an arrangement connecting an air impact tool to the second hydraulic actuator for applying, simultaneously with the static force, high-frequency impulses to the plug entirely through solid members.

Abstract: System for inspecting the interior of tube plugs, particularly tube plugs of the type having expander elements disposed therein. The system includes a probe assembly connectable to the tube plug, the probe assembly having a rotatable and translatable probe carrier housing for housing a sensor probe capable of inspecting the tube plug. The probe assembly also includes a leaf spring extending through the probe carrier housing and attached to the sensor probe for radially outwardly biasing the sensor probe into sensing contact with the interior of the tube plug, particularly the interior of the tube plug located between the top of the tube plug and the expander element. A tangle-free flexible hose is connected at one end thereof to the probe carrier housing for transversely rotating and longitudinally translating the probe carrier housing. The flexible hose is also connected at the other end thereof to a probe driver assembly that rotates the flexible hose which in turn rotates the probe carrier housing.

Abstract: An apparatus and method for remotely inserting and positioning a sleeve-loaded mandrel within a damaged tube mounted in the tubesheet of a nuclear steam generator is disclosed herein. The apparatus of the invention generally comprises a frame, a mounting mechanism for detachably and pivotally mounting the frame to the open end of one of a first tube in the tubesheet, an advancing assembly supported by the frame for remotely inserting and advancing the sleeve-loaded mandrel to a position across a damaged section of the selected tube, and a drive train for pivotally positioning the advancing assembly into alignment with the open end of the selected tube. In the preferred embodiment, the advancing means is formed from the pair of hydraulically operated grippers, one of which is reciprocably movable with respect to the other.

Abstract: An improved fluid mandrel having an eddy current probe connected thereto is disclosed herein. The eddy current probe generally comprises a probe body which is detachably connectable to the bottom of a fluid mandrel on one end, and a source of hydraulic fluid on the other end. The probe body includes a pair of sensing coils which are separated along the longitudinal axis of the body by a distance approximately equal to the thickness of the metallic structure desired to be detected. The improved mandrel finds particular application in performing expansions which eliminate the clearance between heat exchange tubes extending through the baffle plates in nuclear steam generators. In such an application, the sensing coils of the probe are longitudinally spaced the same distance as the thickness of the baffle plates in order to generate a sharp and unambiguous electronic signal indicative of the relative positions of the mandrel and the baffle plate.