Patent Number: 051529572
Section: claims

1. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly, the fuel assembly having clearances among fuel elements; a body fixing section for fixing the body to the fuel assembly for positioning; a recovering working unit for recovering foreign matter; a fiberscope for photographing a working state of the recovering working unit and sending a corresponding image to a remote location; a moving mechanism section for moving the recovering working unit and the fiberscope in one direction and in a direction toward or away from the fuel assembly, allowing the recovering working unit and the fiberscope to be operated in cooperation with each other, the recovering working unit adapted to be guided into the clearances of the fuel assembly, the fiberscope following the recovering working unit; and a remote control section for remotely controlling the operations of the moving mechanism and the recovering working unit on the basis of the image to recover the foreign matter. 2. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly; a body fixing section for fixing the body to the fuel assembly for positioning; a moving mechanism section movable both in one direction and in a direction toward or away from the fuel assembly; a recovering working unit adapted to be moved by the moving mechanism section to gain access to clearances among fuel elements of the fuel assembly to allow foreign matter to be recovered thereby, wherein said recovering working unit is comprised of a needle-like probe; a fiberscope for following the movement of the recovering working unit, while covering the recovering working unit and foreign matter within a viewing field, to photograph a working state of the recovering working unit and to send a corresponding image to a remote location; and a remote control section for remotely controlling the operations of the moving mechanism and recovering working unit on the basis of the image to recover the foreign matter. 3. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly, wherein said body is equipped with a water stream generation section for imparting a propulsion force to the body; a body fixing section for fixing the body to the fuel assembly for positioning; a moving mechanism section movable both in one direction and in a direction toward or away from the fuel assembly; a recovering working unit adapted to be moved by the moving mechanism section to gain access to clearances among fuel elements of the fuel assembly to allow foreign matter to be recovered thereby; a fiberscope for following the movement of the recovering working unit, while covering the recovering working unit and foreign matter within a viewing field, to photograph a working state of the recovering working unit and to send a corresponding image to a remote location; and a remote control section for remotely controlling the operations of the moving mechanism and recovering working unit on the basis of the image to recover the foreign matter. 4. The foreign matter recovering apparatus according to claim 3, wherein said water stream generation section is comprised of a screw propeller and a rudder is provided for adjusting the attitude of said body. 5. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly; a body fixing section for fixing the body to the fuel assembly for positioning; a moving mechanism section movable both in one direction and in a direction toward or away from the fuel assembly; a recovering working unit adapted to be moved by the moving mechanism section to gain access to clearances among fuel elements of the fuel assembly to allow foreign matter to be recovered thereby, wherein said recovering working unit includes a suction nozzle for sucking the foreign matter and a recovery case for recovering the sucked foreign matter; a fiberscope for following the movement of the recovering working unit, while covering the recovering working unit and foreign matter within a viewing field, to photograph a working state of the recovering working unit and to send a corresponding image to a remote location; and a remote control section for remotely controlling the operations of the moving mechanism and recovering working unit on the basis of the image to recover the foreign matter. 6. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly; a body fixing section for fixing the body to the fuel assembly for positioning; a moving mechanism section movable both in one direction and in a direction toward or away from the fuel assembly; a recovering working unit adapted to be moved by the moving mechanism section to gain access to clearances among fuel elements of the fuel assembly to allow foreign matter to be recovered thereby; a fiberscope for following the movement of the recovering working unit, while covering the recovering working unit and foreign matter within a viewing field, to photograph a working state of the recovering working unit and to send a corresponding image to a remote location; and a remote control section for remotely controlling the operations of the moving mechanism and recovering working unit on the basis of the image to recover the foreign matter, wherein said remote control section includes an operation panel having a plurality of joysticks and a display unit for displaying the state of working by the working unit. 7. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly; a body fixing section for fixing the body to the fuel assembly for positioning; a recovering working unit for gaining access to clearances among fuel elements of the fuel assembly and recovering the foreign matter; a fiberscope for recovering the recovering working unit and foreign matter and photographing a state of working by the recovering working; a positioning mechanism section for moving the recovering working unit and fiberscope, as one unit, in a plurality of directions for positioning; a display unit for displaying an image, photographed by the fiberscope, at a remote location; a remote control section for performing a remote control on the basis of the image displayed on the display unit; and a control section for controlling the positioning mechanism section and recovering working unit on the basis of an output of the remote control section. 8. The foreign matter recovering apparatus according to claim 7, wherein said body fixing section is comprised of a guide for guiding the fuel assembly and clamps for holding the fuel assembly therebetween. 9. The foreign matter recovering apparatus according to claim 7, wherein said recovering working unit is comprised of forceps. 10. The foreign matter recovering apparatus according to claim 7, wherein said body includes a water stream generation section for imparting a propulsion force to the body. 11. The foreign matter recovering apparatus according to claim 1 or 7, further comprising a fiberscope oscillation mechanism for swinging the fiberscope and adjusting the direction of its optical end face. 12. A foreign matter recovering apparatus comprising: a body for approaching a fuel assembly; a body fixing section for fixing the body to the fuel assembly for positioning; a working unit for gaining access to clearances among fuel elements of the fuel assembly and recovering a foreign matter there; a fiberscope for covering the recovering working unit and foreign matter and photographing a state of working by the recovering working unit; positioning mechanism section for moving the working unit and fiberscope, as one unit, in a plurality of directions for positioning; a display unit for displaying an image, photographed by the fiberscope, at a remote location; a remote control section for performing a remote control operation on the basis of an image displayed on the display unit; a control unit for controlling the positioning mechanism and recovering working unit on the basis of an output of the remote control section; and a movement restriction section for preventing the recovering working unit from being moved toward the fuel assembly when it is incorrectly displaced relative to very small clearances of the fuel assembly and allowing the recovering working unit to be moved toward the fuel assembly when the recovering working unit is correctly oriented toward the clearance of the fuel assembly to allow it to gain access to the small clearance of the fuel assembly. 13. The foreign matter recovering apparatus according to claim 12, wherein said movement restriction section comprises an engaging projection adapted to, together with the working unit, be displaced as one unit in accordance with a movement of the recovering working unit in a predetermined direction; and a guide member provided integral with the body and having a guide recess which is so set as to have a positional relation to the clearances of the fuel assembly, said guide member being engaged by the engaging projection when the recovering working unit is moved toward the fuel assembly while being incorrectly displaced relative to the very small clearances of the fuel assembly, and being retracted back into the guide recess, upon the movement of the recovering working unit in a direction to correctly align with the small clearance of the fuel assembly, to enable the engaging projection to be moved along the guide recess. 14. The foreign matter recovering apparatus according to claim 12, wherein said movement restriction section is comprised of a guide member provided with the body and having a guide recess provided in a positional relation corresponding to the very small clearances of the fuel assembly and a plurality of proximity sensors which, together with the recovering working unit, are displaced as one unit in accordance with the movement of the working unit in a predetermined direction to detect the position of the guide recess; a position detection section is provided for detecting the position of the recovering working unit when the recovering working unit is spaced apart from the fuel assembly with the working unit placed outside the clearances of the fuel assembly; and said control unit controls the positioning mechanism section and recovering working unit in accordance with the outputs of the remote control section, proximity sensors and position detection section. 15. The foreign-matter recovering apparatus according to claim 14, wherein said position detection section includes a fixing section representing the position of the fuel assembly and a movable body for detecting the position of the clearances of the fuel assembly in a manner to follow the movement of the recovering working unit. 16. The foreign matter recovering apparatus according to claim 14, further comprising a limit sensor for restricting a spacing between the recovering working unit and the fuel assembly when the working unit is retracted back from the fuel assembly.