PURPOSE: To make lower nozzle fitting operation unmanned and to reduce the possibility of exposure in the operation by providing a mechanism which clamps a screw in a screw holder.
CONSTITUTION: A holding mechanism 47 for conveyance locks and holds one of the screw holder 51 where the screw 59 for lower nozzle fixation is put, a lower nozzle N, and a guide plate 7 selectively. Further, a carrying mechanism 40 moves the holding mechanism 42 for conveyance between a mount base 52 for the respective members and the lower end position of a control rod guide pipe. Further, a pressing and fixing mechanism 5 presses the guide plate 7 or screw holder 51 which is locked by the holding mechanism 47 for conveyance against the lower end to the control rod guide tube and fixes it. Then a screw clamping-in mechanism (automatic screw clamper 67) presses the screw 59 in the screw holder to the lower end of the control guide tube through a lower nozzle fixing mechanism which can press the lower nozzle N against the lower end of the control rod guide tube and fixes it and the lower nozzle N fixed by the lower nozzle fixing mechanism.
YAMAZAKI SHUJI
OUCHI MASAKI
