Control rod guide tube cleaning apparatus in nuclear reactor

Abstract

The present invention is a control rod guide tube cleaning apparatus in a nuclear reactor which comprises a rod member, one end side portion of which has the thickness such that the end side portion can pass through an inside of a connecting portion between a housing of a control rod drive mechanism and a control rod guide tube, a nozzle for sucking water, mounted on the rod member on the one end side so that the nozzle can go in and out of the rod member, a means for rotating the rod member in a horizontal direction, and a water passage for leading water sucked in the nozzle to an outside of the housing along the rod member. The rod member is inserted into the control rod guide tube through the inside of the housing. Then, the nozzle is rotated downward so that a suction port of the nozzle faces adjacently to the bottom inside the control rod guide tube. The nozzle is rotated in the horizontal direction by rotating the rod member in the horizontal direction. At the same time, dusts on the bottom inside the control rod guide tube is sucked by the nozzle together with water inside the control rod guide tube to discharge them out of the housing.

What is claimed is:  
     
         1 . A control rod guide tube cleaning apparatus in a nuclear reactor comprising: 
 a rod member, one end side portion of which has such a thickness that the end portion can pass through an inside of a connecting portion between a housing of a control rod drive mechanism and a control rod guide tube;    a nozzle for sucking water, mounted on said rod member on the one end side so as to be able to enter and go out said rod member;    a means for rotating said rod member in a horizontal direction; and    a water passage for leading water sucked in said nozzle to an outside of said housing along said rod member.    
     
     
         2 . A control rod guide tube cleaning apparatus according to  claim 1 , wherein said water passage is formed by making said rod member hollow.  
     
     
         3 . A control rod guide tube cleaning apparatus according to  claim 2 , wherein said nozzle has a nozzle opening opened downward under the condition that said nozzle is disposed outside said rod member.  
     
     
         4 . A control rod guide tube cleaning apparatus according to  claim 3 , wherein said nozzle has a passage opening facing an inlet of said water passage under the condition that said nozzle is disposed outside said rod member, and said passage opening communicates with said nozzle opening.  
     
     
         5 . A control rod guide tube cleaning apparatus according to  claim 4 , wherein said rod member has a thickness such that said rod member can be inserted in said housing of a control rod drive mechanism, and is mounted on a member detachable to said housing of control rod drive mechanism, so as to be movable in the length direction of said housing and rotatable in a horizontal direction.  
     
     
         6 . A control rod guide tube cleaning apparatus according to  claim 5 , wherein a suction pump arranged outside said housing is connected to said water passage.  
     
     
         7 . A control rod guide tube cleaning apparatus according to  claim 6 , wherein a cylinder portion is formed inside said member detachable to said housing of a control rod drive mechanism, a piston portion provided at an intermediate portion of said rod member is combined inside said cylinder portion so as to be movable in the length direction of said housing, and a hydraulic unit arranged outside said housing is connected to said cylinder portion so as to drive said piston portion by hydraulic pressure to move said piston portion in the length direction of said housing.  
     
     
         8 . A control rod guide tube cleaning apparatus according to  claim 1 , wherein a picture taking apparatus for taking, as an image, a cleaning portion and an illumination apparatus for illuminating the cleaning portion each are provided on one end side of said rod member, and a monitor for displaying an image taken by said picture taking apparatus is provided outside said housing.  
     
     
         9 . A control rod guide tube cleaning apparatus according to  claim 7 , wherein an picture taking apparatus and an illumination apparatus are provided on said one end side of said rod member so that said apparatuses can go in and out of said rod member, and a monitor for displaying an image taken by said picture taking apparatus and an operation apparatus for operating said picture taking apparatus and said illumination apparatus to cause said picture taking apparatus and said illumination apparatus to go in and out of said rod member are provided outside said housing.  
     
     
         10 . A control rod guide tube cleaning apparatus in a nuclear reactor comprising: 
 a main body which is generally cylindrical and able to be inserted in a housing of control rod drive mechanism provided on a lower side of a nuclear reactor pressure container;    a rod member for pressing up a control rod, held by said main body so as to be movable in a vertical direction;    a slit-shaped nozzle containing portion formed in the vicinity of a head portion of said rod member; and    a suction nozzle supported by a shaft at one end so as to be rotatable between a vertical direction and a horizontal direction inside said nozzle containing portion.    
     
     
         11 . A control rod guide tube cleaning apparatus in a nuclear reactor comprising: 
 a main body which is generally cylindrical and able to be inserted in a housing of control rod drive mechanism provided on a lower side of a nuclear reactor pressure container;    a rod member for pressing up a control rod, held by said main body so as to be movable in a vertical direction;    a slit-shaped nozzle containing portion formed in the vicinity of a head portion of said rod member;    a suction nozzle supported by a shaft at one end so as to be rotatable between a vertical direction and a horizontal direction inside said nozzle containing portion; and    an endoscope type television camera arranged in side said nozzle containing portion.