Abstract: Provided are a probe and an apparatus for measuring a thickness of an oxide layer of a fuel rod, capable of testing claddings of inner and outer fuel rods of a nuclear fuel assembly without disassembling the nuclear fuel assembly. The probe includes a fuel rod transfer region on which an eddy current sensor capable of continuously testing claddings of outer fuel rods of a fixed nuclear fuel assembly is mounted. Further, the apparatus includes a frame in which a cylinder driven in upward and downward directions is mounted, a first probe connected to one side of the cylinder in order to test claddings of outer fuel rods of a nuclear fuel assembly, and a second probe connected to the other side of the cylinder in order to test claddings of inner fuel rods of the nuclear fuel assembly.

Abstract: Provided is an apparatus for measuring outer diameters of fuel rods of a nuclear fuel assembly, in which the fuel rods are standing upright and are used in a light water reactor. The apparatus includes a support unit fixed to a floor at a lower portion thereof so as to be kept insulated from vibrations caused by external forces, a measuring unit mounted on the support unit and moving up and down to measure the outer diameters of the fuel rods, and a transducer cooperating with the measuring unit, converting the measured outer diameters of the fuel rods into electrical signals, and sending the converted signals to the outside. Thus, the apparatus moves up and down to measure the outer diameters of the fuel rods, so that it can accurately check abnormalities in the outer diameters of the fuel rods.

Abstract: Provided is an apparatus for measuring dimensions of a spacer grid for nuclear fuel assemblies. The apparatus includes a fixing unit fixed to a measuring table placed on a floor and kept insulated from vibrations caused by external force, a measuring unit mounted on the fixing unit and configured so that measuring members are installed on both sides of a rectangular spacer grid and move in forward and backward directions by cylinders while grasping the both sides of the spacer grid, and measure abnormalities in the both sides of the spacer grid, and a displacement measuring unit mounted on one side of the measuring unit and sending the measured abnormalities in the both sides of the spacer grid to the outside.