CUTTING/DISASSEMBLING METHOD OF LARGE-SIZED TUBULAR STRUCTURE FORMED FROM REINFORCED CONCRETE CONSTRUCTION, AND CUTTING/DISASSEMBLING DEVICE

PROBLEM TO BE SOLVED: To proceed with cut/disassembly from a lower part by preparing a cutting/disassembling device on a work floor of a reactor, suspending an upper part of a reactor shield wall and remotely controlling the cutting/disassembling device.SOLUTION: A U-shaped guide frame 11 is U-shaped of which a front end is open in a planar view, for traveling around a wire saw 10. The wire saw 10 in a portion crossing a gap between opening parts of the U-shaped guide frame 11 is displaced forwards and backwards by parallel movement. A wire-saw cutter is supported in a front part of a work vehicle 14 moving on a work floor 3 in such a manner that the U-shaped guide frame 11 is movable upwards and downwards in parallel. Such a cutting/disassembling device 20 is carried onto the work floor 3, and the U-shaped guide frame 11 is pressed against an outer circumference of a large-sized tubular structure to proceed with horizontal cutting by driving the wire saw 10 crossing the gap between the opening parts. Further, the U-shaped guide frame 11 is moved vertically upwards or downwards to perform vertical cutting and a portion of the large-sized tubular structure is cut away by proceeding with return horizontal cutting.