Two cutting techniques have been developed for dismantling the pipes connected to the Japan Power Demonstration Reactor (JPDR) pressure vessel. They are the rotary disk knife cutting system for dismantling relatively large pipes, such as the primary cooling system, and the shaped explosive cutting system for cutting relatively small pipes in air or water. Basic cutting tests were performed to determine the optimum characteristics of the cutting systems and to conduct a safety evaluation by studying the effects of blasting on surrounding areas. Mock-up tests confirmed the applicability of the newly developed dismantling systems for JPDR dismantlement by successfully cutting test pipes with these systems.