An apparatus for remotely inspecting a nuclear reactor, comprising: a core shroud having an annular rim; a partial upper track positioned on the annular rim of the core shroud and horizontally movable along the annular 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 to the partial upper track, and structured to drive the head along the partial upper track and to drive the partial upper track along the annular rim; a second driving mechanism connected to the frame and structured to drive the lower track along the core shroud; characterized in that the assembly further comprises a third driving mechanism connected to the carriage and structured to drive the 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 is horizontally drivable into a different position along the annular rim of the core shroud. a core shroud having an annular rim; a partial upper track positioned on the annular rim of the core shroud and horizontally movable along the annular 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 to the partial upper track, and structured to drive the head along the partial upper track and to drive the partial upper track along the annular rim; a second driving mechanism connected to the frame and structured to drive the lower track along the core shroud; 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 to the partial upper track, and structured to drive the head along the partial upper track and to drive the partial upper track along the annular rim; a second driving mechanism connected to the frame and structured to drive the lower track along the core shroud; a third driving mechanism connected to the carriage and structured to drive the 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 is horizontally drivable into a different position along the annular rim of the core shroud.