Development of fuel exchange equipment for the new prototype ATR 'Fugen'

In the Fugen, the aim is the fuel cycle of plutonium self-sustaining type without reducing the rate of operation of the reactor, and the reactor is designed so that fuel exchange can be carried out during its operation. The fuel exchange equipment inserts or takes out fuel assemblies through the bottom of reactor pressure tubes, and moves spent fuel to a fuel exchange pool in a containment vessel and receives new fuel also from there. The spent fuel in the fuel exchange pool is discharged to a fuel storage pool through a transfer chute penetrating obliquely the containment vessel. The operation of the machinery in the containment vessel is carried out by the remote control from the central control room. The fuel exchange equipment must carry out with certainty the handling of fuel assemblies and sealing plugs. Also it must be connected easily to the pressure tubes, and must not damage them if an earthquake occurs during the connection, while the water tightness of the primary cooling system must be maintained. In order to cope with these problems, sealing plug, grab to handle the sealing plug, snout to connect the fuel exchange equipment and the pressure tubes, and other main parts were developed, made, and tested. On the basis of the results, under the conditions simulating the fuel exchange during the reactor operation, the machine same as the actual equipment, made for trial, was operated, and the function of fuel exchange and the maintainability were demonstrated. (Kako, I.)