Abstract: A housing for an underwater processing device, for example, welding, includes a welding head movable laterally relative to the housing and the direction of the weld. At opposite ends, gates are provided having arcuate convex surfaces forming edge seals for engaging in the groove of the work surface. In one form, the gates are linearly slidable and biased in a direction away from the housing. In another form, the gates are pivotally mounted for engaging in the grooves. In both cases, the compliant seal about the margin of the housing, together with the arcuate seal of the gates, maintains a substantially water-free area within the housing to enable processing.

Abstract: An underwater exclusion device includes a housing for a welding torch having leading and trailing arrays of pivotal fingers for engaging in grooves along a work surface to exclude water from an exclusion area within the housing containing the welding torch. The fingers are pivotally mounted and independently and individually movable under the bias of springs between retracted and extended positions. The fingers have radiussed distal ends for engaging the work surface. Upon application of the device to the work surface, the leading and trailing arrays of fingers are displaced under spring pressure to engage their distal ends against the work surface, excluding water from within the housing. The side walls of the housing carry seals for seating along the work surface to prevent water incursion in gaps between the side walls and the work surface.

Abstract: Methods and apparatus for machining a pipe in a reactor pressure vessel (RPV) of a nuclear reactor are described. In one embodiment of the apparatus, a EDM tool facilitates machining an opening in a pipe from within the bore of the pipe. More particularly, and in accordance with one embodiment of the present invention, the EDM tool includes a housing, a linear motion guide, a cam, and an electrode. The housing is sized to fit within the pipe bore and includes a first end and a second end, and an electrode bore extends longitudinally through the housing and is sized to receive the electrode. The cam is slidably coupled to the housing so that the cam moves between the respective housing first and second ends. The electrode is positioned within the electrode bore of the housing and is coupled to the cam so that the electrode may move relative to the electrode bore.