Patent Number: 053316754
Section: summary

BACKGROUND OF THE INVENTION (1) Field of the Invention The present invention relates to an apparatus and a method for control rod exchange work during the regular inspection of a nuclear power plant using a boiling water reactor (referred to BWR), and more particularly an apparatus and a method for attaching or taking off a control rod (referred to CR), and for easily handling a fuel support piece (referred to FS). (2) Description of the Prior Art Conventionally, the spud coupling is used for connecting a CR and a control rod drive mechanism (referred to CRD) in a BWR. In the CR exchange work, such fittings as described in Japanese Patent Laid-Open No. 103399/1981 were presented. However, in a BWR where the above-mentioned spud coupling is adapted, there is the possibility that the connection between a CR and a CRD is disconnected for some reason during plant operation. If such disconnection takes place during plant operation, normal power control become impossible and it is needed to shut down the plant operation. The bayonet coupling is a way solving the above-mentioned problem of the CR-CRD disconnection. In the work of exchanging a CR to which the bayonet coupling is applied, a coupling socket, namely, a CR must be rotated by a predetermined angle for disconnecting the connection. Then, it is necessary to provide an apparatus for rotating a CR in the work of exchanging a CR to which the bayonet coupling is applied. A method for exchanging a CR to which the bayonet coupling is applied was proposed in Japanese Patent Laid-Open No. 205795/1990. In this method, after a FS is taken out above the upper grid plate by using an exclusive handling equipment for a FS, the CR is grasped by use of a CR handling apparatus attached to a fuel exchange apparatus, disconnected from the CRD by rotation and taken out above the upper grid plate by a subsidiary hoist of a fuel exchange apparatus. In attaching a new CR, the CR is connected to the CRD by using the above-mentioned CR handling apparatus in reverse procedures to the above-mentioned procedures and the FS is attached to a reactor core support plate by using an exclusive handling equipment for a FS. This prior art premises that the FS is taken out by the exclusive handling equipment for a FS. Therefore, in applying the prior art, many steps such as attaching or taking off the exclusive handling equipment for a FS and the CR handling apparatus to or from the subsidiary hoist, winching up or down the exclusive handling equipment for a FS and the control rod handling apparatus into or out of the reactor core and so forth are needed, which brings about much time consuming work. SUMMARY OF THE INVENTION (1) Objects of the Invention The present invention has been achieved in the consideration of the above-described problems, and is aimed at providing an apparatus and a method which can shortening the time for exchanging a CR by disconnecting or coupling a CR and a CRD, and taking out or in a CR and a FS continuously. (2) Method Solving the Problem A CR handling apparatus of the present invention for disconnecting or coupling the CR and the CRD using the bayonet coupling, comprises a member for connection attached to a fuel exchange apparatus, a fixing part having guides to be seated at the top face of an upper grid plate in a reactor vessel and to be supported by the upper grid plate, a CR handling part having a CR grasping instrument, a FS handling part having a FS grasping instrument, a means for vertically moving the FS handling part and a means for rotating the CR handling part, the FS handling part and the means for vertically moving the FS handling part. The first method for disconnecting the CR and the CRD by using the above-mentioned CR handling apparatus, comprises the steps of getting down the CR handling apparatus attached to the fuel exchange apparatus, seating the fixing part at the upper grid plate, lowering the FS handling part, seating the bottom part of the FS handling part at the top face of the FS, positioning the FS handling part, grasping the FS and lifting the FS above the upper grid plate, grasping the CR, rotating the CR handling part grasping the CR and the FS handling part grasping the FS by a predetermined angle, disconnecting the connection between the CR and the CRD, and taking out the CR and the FS from the reactor core. And the first method for coupling the connection between the CR and the CRD by using the above-mentioned CR handling apparatus comprises the steps of the reverse procedures to the above-mentioned first method for disconnecting the connection between the CR and the CRD. And the second method for disconnecting the CR and the CRD by using the above-mentioned CR handling apparatus, comprises the steps of getting down the CR handling apparatus attached to the fuel exchange apparatus, seating the fixing part at the upper grid plate, lowering the FS handling part, seating the bottom part of the FS handling part at the top face of the FS, positioning the FS handling part, grasping the FS and lifting the FS above the top part of the CR, grasping the CR, disconnecting the connection between the CR and the CRD by rotating the CR handling part grasping the CR and the FS handling part grasping the FS by a predetermined angle, lifting the FS handling part by the position right below the upper grid plate, rotating the CR handling part and the FS handling part reversely to the above-mentioned rotation by the predetermined angle, and taking out the CR and the FS from the reactor core. And the second method for coupling the CR and the CRD by using the above-mentioned CR handling apparatus comprises the steps of the reverse procedures to the above-mentioned second method for disconnecting the connection between the CR and the CRD.