CUTTING AND DISMANTLING METHOD AND CUTTING AND DISMANTLING APPARATUS OF LARGE CYLINDRICAL STRUCTURE MADE OF REINFORCED CONCRETE OR THE LIKE

PROBLEM TO BE SOLVED: To provide a cutting and dismantling method for cutting and dismantling a reactor from a lower part adjacent to a reactor core where radiation level is high while lifting upper part of a shielding wall of the reactor and a wire saw type cutting and dismantling apparatus used for implementation of the method.SOLUTION: The wire saw type cutting and dismantling apparatus includes: an U-shaped guide frame with an upper part opened wider than a thickness of wall of a large cylindrical structure for allowing a wire saw to run around on the guide frame, and the frame is arranged to perform auto travel in a longitudinal direction along a track. The wire saw runs crossing the U-shaped guide frame with an upper part opened horizontally, and the U-shaped part is arranged to perform parallel movement vertically. The wire saw type cutting and dismantling apparatus is carried in to a work floor and is disposed so that the upper opened U-shaped guide frame receives a lower end portion of the large cylindrical structure. The wire saw is driven to travel around the frame and perform vertical movement upward to cut the wall vertically as well as to cut the wall horizontally by moving the U-shaped guide frame along the track while maintaining the height of the wire saw, and subsequently, to perform a vertical cutting by shifting the wire saw downward to cut off the part of the structure.