Japan Atomic Energy Agency (JAEA) has been developing a reliable disassembly system for FBR fuel reprocessing as a part of Fast Reactor Cycle Technology Development (FaCT). As FBR fuel pins are installed in a hexagonal shaped wrapper tube made of stainless steel, the fuel pins should be separated from the wrapper tube prior to the shearing process. JAEA has been developing the laser beam cutting method and the mechanical cutting method as the disassembly system. Although Fiber laser system showed a good cutting performance, it couldn’t completely avoid fuel pin damage and adhesion during the cutting operation. So we focused on the mechanical method to minimize such troubles. Two types of mechanical cutting modes have to be developed to realize the disassembly procedure, namely, the slit-cut for the wrapper tube and the crop-cut for the end plug region of the fuel pin bundle. To ensure disassembly technology of commercial reactor fuel assemblies, we designed and fabricated the testing machine of disassembly system having the cutting modes in engineering scale. We confirmed basic functions of this machine and improved its performance. We will soon demonstrate engineering operation by a series of disassembling and pin bundle handling procedure; separating fuel pins from wrapper tube, transferring them to the fuel magazine for shearing. Scattering of cutting dust cause machine troubles and transition of it to the dissolution process together with pins causes unknown problems. To resolve the problems, collection device of cutting dust will be tested and the cutting condition to make the disassembly easy to cut will be improved.
A Fundamental Study on Rock Excavation using the Mechanical Cutting Method Combined with Thermal Action by Flame (2nd Report)
