DEVICE AND METHOD FOR ELECTRIC DISCHARGE MACHINING INSIDE CORE SHROUD

PROBLEM TO BE SOLVED: To carry out preventive maintenance and repair for in-reactor structures securely through laser-light irradiation by positioning an object easily, quickly and accurately by remote control from above a reactor. SOLUTION: A device is equipped with an access device 5 for the tool access to a machining position inside a core shroud 2 and an electric discharge machine 6 that is detachably mounted on the access device 5. The access device 5 has an upper end fixing part 7 which is fixed into an interstice between lattices of a top guide or a hole for supporting fuel of a core support, a lower end fixing part 11 which is fixed into an upper end of a control rod drive mechanism housing 4, a rotary rod 9 which is linked between the part 7 and the part 11 and can rotate on its vertical axis and a chuck 22 for installing the electric discharge machine 6 which is mounted on the lateral part of the rotary rod 9 so that it can advance and retreat and whose horizontal and vertical positions can vary. The electric discharge machine 6 has a locking part 25 which is locked to the chuck 22 of the access device 5 and a main body part 6a for electric discharge machining which is linked to the locking part 25 and conducts electric discharge machining in the machining position. COPYRIGHT: (C)2005,JPO&NCIPI