Detection device for abrasion of control rod cluster

The present invention provides a device for detecting abrasion and flaws on cladding tubes of all control rods of control rod clusters of a PWR type reactor in a short period of time. Namely, a guide plate has guide holes disposed in an arrangement corresponding to control rods of the control rod clusters to allow all control rods to pass through. Annular flaw detection probes are disposed to the peripheries of all the guide holes. The guide plate is mounted detachably to a control rod handling tool for moving the control rod clusters stored in a rack vertically and horizontally. When detection is carried out, the guide plate is positioned, by a handling tool, on the rack on which the control rod clusters as objects of detection are stored. Then, the control rod clusters as objects of detection are moved vertically by a lifting mechanism of the handling tool by way of the guide plate. There can be collected data on flaw detection over the entire circumference of the cladding tubes of all the control rods during movement in axial direction by one operation. (I.S.)