Progress state of the decommissioning of Rikkyo University reactor in FY2012

Rikkyo University Atomic Energy Research Institute submitted the file for the decommissioning plan change in 2012 toward the reactor facility demolishment, received the approval, and is promoting the decommissioning work on the research reactor with a schedule for two years from 2012. Since the decommissioning work of FY2012 has finished, this paper reports this progress state. The contents of the decommissioning work plan are to make the reactor facilities stationary condition by performing the following works: (1) implementation of decontamination and removal of the core internals within nuclear reactor facilities, (2) attainment of the state, in which the operation associated with the generation of radioactive waste, does not occur, (3) stop of partial functions of the facilities under performance maintaining, including the disposal facilities of liquid waste, and (4) storage of dismantled materials in vessels after partial dismantling and removal. This paper reports the operations conducted in FY2012, such as the decontamination and removal of the core internals of the nuclear reactor, removal of pneumatic tubes and sample transfer tubes, and function stop measures for plumbing system belonging to the reactor accessory facilities. (A.O.)