Feasibility Study of Disassembly Technologies of Fast Reactor Fuel Assembly

Abstract

In the development of disassembly technologies for the fast reactor fuel assembly, laser cutting was used in tests done in the United Kingdom and the United States due to problems of wear and breakage of cutting-off wheels (CWs); however, the laser can cause thermal damage to fuel pins, melting the part of the fuel pins under the wrapper tube and releasing radioactive materials. Laser cutting conditions to mitigate thermal damage of fuel pins, and development of CWs with appropriate durability to withstand wear and breakage damage were studied. A mock-up machine to be used with a simulated fuel assembly of the fast reactor Monju was designed and manufactured, and the test to confirm the proposed disassembly procedure was conducted. Laser cutting with the reviewed cutting conditions, mechanical cutting with controlled feed speed using CWs, and the disassembly procedure tested with the mock-up machine were confirmed to be workable disassembly technologies.