Abstract: A nuclear reactor vessel has a nozzle plug in its cold leg and hot leg nozzles for isolating the reactor vessel from the balance of the reactor coolant loop. The nozzle plug is mechanically compression fitted with the nozzle without the need for hydraulic or pneumatic actuation. The plug has a primary seal ring compressed against the inner wall of the nozzle and a secondary seal ring compressed against the end wall of the nozzle for withstanding a pressure differential of about 34 feet of water.

Abstract: Calibration arrangement and method for calibrating an inspection instrument, such as an ultrasonic inspection instrument of the kind typically used to inspect nuclear reactor pressure vessels. The calibration arrangement comprises a frame, the frame having a slot therethrough for receiving a sonic coupling medium therein. A plurality of channels extend through the frame and are in communication with the slot. A plurality of solid reflector rods matingly extend through respective ones of the channels and into the slot for reflecting sonic energy produced by a pulsed ultrasonic transducer mounted on the frame and spanning the slot. A pulser stimulates the transducer so that the transducer transmits pulsed sonic energy through the coupling medium which resides in the slot. The sonic energy is reflected by the rods that pass through the slot. The reflected sonic energy or echoes are received by the transducer, which generates transducer output signals that are received by a receiver.

Abstract: An improved robotic arm which is capable of accurately manipulating a testing device beneath the tube sheet of the steam generator and accurately and consistently return to a selected tube location is provided. The robotic arm includes a base which is adapted to be fixedly secured to a support beam which initially positions the robotic arm within the steam generator, a first extension arm which is rotatably mounted on the base forming a primary rotation joint and which extends essentially parallel to the tube sheet. A second extension arm is rotatably mounted at the end of the first extension arm forming a secondary rotation joint and further extends therefrom. The testing device such as an eddy current inspection tool is positioned at a distal end of the second extension arm.

Abstract: An ultrasonic probe for the weld inspection of nuclear reactor vessel nozzles is constructed from a plurality of segments interconnected by means of a flexible joint and protected by bumpers of various shapes. The probe is capable of successfully operating in an underwater and radioactive environment under remote control while maintaining a high degree of control over the placement and movement of the included transducer assembly for performing contact type testing. The transducer assembly, which includes an ultrasonic transmitter and receiver, is mounted within an ultrasonic sensor body which permits insertion of the probe within a nozzle of a reactor vessel while maintaining direct surface to surface contact with the nozzle for weld area examination by contact type testing.

Abstract: A universal tool for the weld inspection of tubular objects such as reactor vessels is disclosed. The tool is constructed from an array of transducers mounted in groups for common inspection of a particular weld volume. The individual transducers, as well as the groups, are arranged in a compact assembly for minimizing the overall dimensions of the tool and its corresponding weight. The transducers are arranged in a manner which permits inspection of tubular objects having different radii of curvature and corresponding different diameters with a single tool without the need of having to individually adjust the orientation angles of the transducers.

Abstract: Calibration apparatus for calibrating an ultrasonic transducer array by moving it along an arcuate calibration test member, includes four upright posts interconnected by a rectangular carriage which is slidably movable vertically along the posts. A horizontal pivot shaft is rotatably mounted on the carriage. Fixed to the shaft and depending therefrom are two pendulum arms, interconnected at their lower ends by a pair of cross bars on which is slidably mounted a mounting block. An attachment rod is vertically slidably movable in the mounting block and carries a coupling joint at its lower end for mounting the transducer array. A reversible gearmotor drives the pivot shaft through a chain and sprocket assembly in an oscillating motion. Backlash in the gear train is reduced by a bias weight.