Device and method for repairing inside of reactor pressure vessel

Abstract

An opening portion 3 is produced by cutting a recirculating piping 72 connected to a recirculating nozzle 2 of a reactor pressure vessel 1. A repairing device is brought into an annulus 10 of the reactor pressure vessel 1 from the opening 3, thereby repairing the annulus 10.

What is claimed is:  
     
         1 . A method for repairing the inside of a reactor pressure vessel for a boiling water reactor provided with a recirculating nozzle, the method comprising steps of: 
 draining coolant in said reactor pressure vessel;    cutting a recirculating piping connected to said recirculating nozzle to produce an opening connected to said recirculating nozzle;    bringing a repairing device into an annulus in said reactor pressure vessel from said opening; and    using said repairing device to repair the inside of said annulus.    
     
     
         2 . A method for repairing the inside of a reactor pressure vessel for a boiling water reactor provided with a recirculating nozzle, the method comprising steps of: 
 draining coolant in said reactor pressure vessel;    removing a recirculating piping connected to said recirculating nozzle from a recirculating pump to produce an opening connected to said recirculating nozzle;    bringing a repairing device into an annulus in said reactor pressure vessel from said opening; and    using said repairing device to repair the inside of said annulus.    
     
     
         3 . A method for repairing the inside of a reactor pressure vessel according to  claim 1  and  claim 2 , wherein at least either inspecting a repaired part with a camera, installing monitoring cameras during repairing, detecting flaws with ultrasonic, or beveling for repairing with electrical discharge machining is conducted from the top of said pressure vessel before the coolant in said reactor pressure vessel is drained.  
     
     
         4 . A method for repairing the inside of a reactor pressure vessel for a boiling water reactor according to  claim 1  and  claim 2 , the method comprising further steps of: 
 bringing said repairing device into said reactor pressure vessel through said opening; lifting up/down said repairing device with a jig for lifting-up/down;  
 separating said repairing device from said jig for lifting-up/down after said repairing device reaches the height of a baffle plate;  
 installing said repairing device on said jig for lifting-up/down again after repairing the inside of the reactor; and  
 recovering said repairing device from the inside of the reactor.  
 
     
     
         5 . A method for repairing the inside of a reactor pressure vessel according to  claim 4 , wherein said jig for lifting-up/down is brought in by a straight or curved guide held by a jig for bringing-in through said opening.  
     
     
         6 . A device for repairing the inside of a reactor pressure vessel comprising: 
 an operation tool, which is used to repair an inside of an annulus when coolant in a reactor pressure vessel of a boiling water reactor provided with a recirculating nozzle is drained, a recirculating piping connected to said recirculating nozzle is cut to produce an opening connected to said recirculating nozzle, the repairing device is brought into said annulus in said reactor pressure vessel from said opening; and    suction disk pads;    wherein said repairing device is constituted so as to stick to a wall face inside said annulus to maintain an attitude.    
     
     
         7 . A device for repairing the inside of a reactor pressure vessel comprising: 
 an operation tool, which is used to repair an inside of an annulus when coolant in a reactor pressure vessel of a boiling water reactor provided with a recirculating nozzle is drained, a recirculating piping connected to said recirculating nozzle is cut to produce an opening connected to said recirculating nozzle, the repairing device is brought into said annulus in said reactor pressure vessel from said opening;    suction disk pads; and    driving rollers;    wherein said repairing device is constituted so as either to travel in the horizontal direction or to turn while maintaining the attitude by sticking to a wall face inside said annulus.    
     
     
         8 . A device for repairing the inside of a reactor pressure vessel according to  claim 7  further comprising: 
 multiple joints for changing the shape of said repairing device according to the curvature of a wall face inside said annulus.  
 
     
     
         9 . A device for repairing the inside of a reactor pressure vessel according to  claim 8  further comprising: 
 encoders for detecting the rotations of said driving rollers and the angles of said joints;  
 wherein said repairing device is constituted so as to calculate either a position inside said reactor pressure vessel, the curvature of the inner wall face, or a distance between the nuclear pressure vessel and a jet pump diffuser.  
 
     
     
         10 . A device for repairing the inside of a reactor pressure vessel according to  claim 8  further comprising: 
 double-sided suction disk pads for traveling on discontinued and separated wall faces such as a wall face of the reactor pressure vessel to an outer face of the jet pump diffuser.  
 
     
     
         11 . A device for repairing the inside of a reactor pressure vessel according to either one of claims  7  to  9  further comprising: 
 an operation tool driving mechanism conducting at least one type of motion of traveling said operation tool up/down and rotationally, and moving said operating tool while swinging it;  
 wherein said operation tool is either a welding torch, a laser head, an electric discharge machining device, a camera, a grinder, a dust collector, a device for applying liquid penetrant for detecting flaws, cleaning, and inspecting, an ultrasonic probe, or a dimension measuring device, and these tools are changed to conduct repairing such as welding, laser machining, electric discharge machining, visual inspection, polishing, grinding, collection dusts and chips, detecting flaws with liquid penetration, detecting flaws with ultrasonic, and measuring dimension.  
 
     
     
         12 . A device for repairing the inside of a reactor pressure vessel according to either one of  claims 7  to  9 , wherein the operation tool installed on said repairing device is a cable/hose relay box, said repairing device is brought inside the annulus after a first repairing device including the operation tool to relay cables and hoses for the first repairing device, and said repairing device supports routing the cables and the hoses from the nozzle to the first repairing device.  
     
     
         13 . A device for repairing the inside of a reactor pressure vessel according to either one of  claims 7  to  12 , wherein said repairing device is constituted such that said repairing device extends arms or cushions to a wall face on the opposite side for pushing the wall face for fixing when said device is fixed on a part of a wall face where the suction with the suction disks is difficult.  
     
     
         14 . A device for repairing the inside of a reactor pressure vessel according to  claim 5 , wherein said jig for bringing-in is provided with a member for shielding radiation so as to add a function for shielding radiation irradiated from the reactor pressure vessel when an operator comes close to a cut part on a recirculating piping, an outlet nozzle for recirculating water, or a safe end of the outlet nozzle for recirculating water.  
     
     
         15 . A device for repairing the inside of a reactor pressure vessel according to  claim 5 , wherein said jig for bringing-in is provided with a bendable self-traveling mechanism, and is constituted so as to travel by itself to bring in said repairing device when said repairing device is brought into the reactor pressure vessel through a bent piping from said opening.  
     
     
         16 . A device for repairing the inside of a reactor pressure vessel according to  claim 11 , wherein said device for applying liquid penetrant for detecting flaws, cleaning, and inspecting has an airbag mechanism and a liquid suction nozzle, and an enclosed space is formed around a part to be repaired by pressing said airbag mechanism against the part to be repaired, thereby sucking the liquid penetrant for detecting flaws and cleaning liquid without diffusing, resulting in eliminating cleaning a wide area other than the subject part.  
     
     
         17 . A device for repairing the inside of a reactor pressure vessel according to  claim 11 , wherein said electric discharge machining device is provided with an airbag mechanism, a machining liquid injection nozzle, a machining liquid suction nozzle, and an electric discharge machining electrode, and an enclosed space is formed around a part to be repaired by pressing said airbag mechanism against the part to be repaired, the electric discharge electrode is pressed on a face to be machined to conduct electric discharge machining while the machining liquid is flowing from said machining liquid injection nozzle, thereby sucking machining chips without diffusing, resulting in conducting local electric discharge machining under an aerial environment without water.  
     
     
         18 . A method for repairing the inside of a reactor pressure vessel according to either of  claims 1  to  3 , the method comprising further steps of: 
 inspecting a part to be repaired with a camera from the top of the reactor pressure vessel, and beveling for repairing with an electric discharge device brought to the part to be repaired through a guide pipe installed in water from both the annulus side and the inside of the nuclear reactor in a submersed state before coolant in the reactor pressure vessel is drained;  
 draining coolant;  
 bringing in the repairing device with said method from an opening on recirculating piping, an outlet nozzle for recirculating water, or a safe end of the outlet nozzle for recirculating water in an aerial state; and  
 bringing in another repairing device into the nuclear reactor through said guide pipe from the top of the reactor pressure vessel;  
 wherein repairing operation is conducted both from the annulus side and the inside of the nuclear reactor side, and the same part is repaired from the both sides.