2020 Volume 19 Issue 2 Pages 65-75
Japan Atomic Energy Agency (JAEA) has been developing an advanced head-end process based on a disassembly machine using cutting technology as well as a shearing machine with short-stroke shearing for reprocessing fast reactor (FR) fuel assemblies. The FR fuel pins should be removed from the fuel assembly wrapper tube by cutting without damage to reprocess them. In this paper, the applicability of fiber laser cutting as a promising cutting technology for disassembly machines is reported. Toward solving problems such as the welding of wrapper tubes and spacer wires, cutting tests (slit cut and crop cut) using simple test pieces and mock-up tests using a simulated fuel assembly were carried out to determine optimal cutting conditions (e.g., power, cutting speed, focus position, and cutting position (lower plug/knock bar)) and procedure. Under the selected cutting conditions and procedure, damage to the fuel pin and the welding of the spacer wires were reduced, demonstrating that cutting using a fiber laser can be applied to disassemble FR fuel assemblies.
