Fuel exchanger for FBR type reactor

Crown-like oblique protrusions are disposed at the upper and the lower portions of a fuel for positioning to a predetermined direction when the fuel is inserted to a reactor core by a fuel exchanger. If this confirmation method is applied to a large scaled reactor, holes are greatly deformed relatively due to the increase of fuel life so that the positioning may sometimes fail. Further, since a great number of fuels have to be exchanged at a time, misoperations must be detected. Then, there are disposed a orientation rod detachably provided to a fuel catching and releasing gripper, a fuel rotational driving mechanism that can be operated rotationally from the outside of the reactor and a fuel discrimination device comprising a ultrasonic wave tranceiver disposed at a position opposing to a discrimination pattern comprising a combination of circular grooves formed at the top of the fuel. In this way, the rotational direction of the fuel can be set and the kind of the reactor core constituent elements caught by the exchanger can be discriminated by the fuel discrimination device in a state where the pantograph arms are folded. (N.H.)