Apparatus and method to inspect, modify, or repair nuclear reactor core shrouds

An apparatus for remotely inspecting a core shroud of a nuclear reactor, comprising:

• a partial upper track positioned on an annular rim of the core shroud and horizontally movable along the rim;
• an assembly, comprising:
• a head movably connected to the partial upper track such that the head is horizontally movable along the partial upper track;
• a lower track;
• a frame having a first end and a second end, the first end being mounted to the head and the second end being connected to the lower track such that the lower track is horizontally movable along the core shroud;
• a carriage movably connected to the lower track;
• a scan arm connected to the carriage and extending vertically downward along the core shroud;
• at least one sensor connected to the scan arm for inspecting the core shroud;
• a first driving mechanism connected to the head and the partial upper track, and structured to drive the head along the partial upper track and to drive the partial upper track along the rim;
• a second driving mechanism connected to the frame and structured to drive the lower track along the core shroud;
• and
• a third driving mechanism connected to the carriage and structured to drive said carriage along the lower track;
• and
• a track brake system connected to the partial upper track,
• wherein, when the track brake system is activated, the partial upper track remains stationary and the head is movable along the partial upper track, and
• wherein, when the track brake system is deactivated, the partial upper track can be driven into a different position along the annular rim of the core shroud.