Patent ID: 7133488

Claim:
A neutron flux mapping system for a nuclear reactor comprising: drivers each including a geared motor, a helical gear driven by the geared motor, and a storage reel adapted to supply, to the helical gear, a detector cable carrying a detector; and a double indexing path selector unit including a body including upper and lower fixed plates, and tie rods connecting the upper and lower fixed plates, a fixed shaft fixedly mounted at a central portion of the body, an outer path selector arranged to be rotatable about the fixed shaft, the outer path selector including an upper rotating plate arranged to be rotatable about the fixed shaft while carrying a drive unit for rotating the outer path selector about the fixed shaft, and a control unit for controlling the drive unit, and a lower rotating plate arranged to be symmetrical with the upper rotating plate, and connected to the upper rotating plate to rotate along with the upper rotating plate, and inner path selectors each including a hollow rotating shaft rotatably mounted between the upper and lower rotating plates of the outer path selector, a path select tubing connected, at an upper end thereof, to an upper end of the rotating shaft in the interior of the rotating shaft while extending downwardly and radially outwardly from the rotating shaft through a hole formed at the rotating shaft, and a disc mounted to a lower end of the rotating shaft, and provided with a plurality of circumferentially-arranged paths.