This invention relates to nuclear steam generators and more particularly to apparatus for remotely repairing the tubes in the nuclear steam generator.
In pressurized water nuclear reactors primary fluid or coolant is pumped through a reactor and a steam generator, radioactive contaminants in the primary fluid are deposited on the tubes and in the channel head of the steam generator so that repair crews are subjected to significant radioactivity when working within the channel head. Therefore, in order to reduce the exposure of personnel to radiation, it is desirable to provide an apparatus which can be remotely operated, can effectively inspect, and can repair the tubes within the steam generator.
In general, apparatus for remotely repairing tubes disposed in a tube sheet in a channel head of a steam generator having a manway disposed in the head, when made in accordance with this invention, comprises a column rotatably disposed in the head generally perpendicular to the tube sheet, a boom pivotally mounted on the column, and means for rotating the column and the boom therewith. The apparatus also comprises means for pivoting the boom from a position generally parallel to the tube sheet to a position generally aligned with the manway, a carriage disposed to ride lengthwise along the boom, a tool operable on a tube, a tool holder disposed on the carriage, means for moving the carriage lengthwise along the boom and means disposed on the carriage for moving the tool holder along an axis parallel to the axis of a tube, whereby the apparatus will perform repair operations on the tubes.