Dismantling Method of Fuel Cycle Facilities Obtained by Dismantling of the JRTF

The Japan Atomic Energy Research Institute Reprocessing Test Facility (JRTF) was the first reprocessing facility which was constructed by applying only Japanese technology to establish basic technology on wet reprocessing. JRTF had been operated since 1968 to 1969 using spent fuels (uranium metal/aluminum clad, about 600kg as uranium metal and 600MWD/T) from the Japan Research Reactor No.3 (JRR-3). Reprocessing testings on PUREX process were implemented at 3 runs, so that, 200g of plutonium dioxide were extracted. After JRTF was shut down at 1970, it had been used for research and development of reprocessing since 1971. The more mature research and development of nuclear are, the more opportunity of dismantling of old nuclear facilities would be. Japan Atomic Energy Agency (JAEA) has an experience of full scale of dismantling through decommissioning of Japan Power Demonstration Reactor (JPDR)1). On the other hand, we didn’t have that of fuel cycle facility. Moreover, it is considered that dismantling methods of nuclear reactor and fuel cycle facility are different for following reason, components contaminated TRU nuclide including Pu, and components installed inside narrow cells. Dismantling methods are important factor to decide manpower and time for dismantling. So, it is indispensable to optimize dismantling method in order to minimize manpower and time for dismantling. Considering the background mentioned above, the decommissioning project of JRTF was started in 1990. The decommissioning project of JRTF is carried out phase by phase. Phase 1; Investigation for dismantling of the JRTF2)3)4). Phase 2; R&D of decommissioning technologies for dismantling of the JRTF5)6)7)8). Phase 3; Actual dismantling of the JRTF9)10). There were several components used for reprocessing and a system for liquid radwaste storage, and those were installed inside of each of several thick concrete cells. The inner surfaces of each cell were contaminated by TRU nuclides including Pu. In phase 3, components used in reprocessing and a system for liquid radwaste storage were dismantled. Moreover, opening was made in concrete walls (including ceiling) for this work. Effective practices for dismantling fuel cycle facilities were obtained through these works. On this report, effective dismantle methods obtained by actual dismantling activities in JRTF are introduced.