Status of the support researches for the regulation of nuclear facilities decommissioning in Japan

In Japan, 4 nuclear power stations are under decommissioning and some nuclear fuel cycle facilities are expected to be decommissioned in the future. On the other hand, the safety regulation of decommissioning of nuclear facilities was changed by amending act in 2005. An approval system after review process of decommissioning plan was adopted and applied to the power stations above. In this situation, based on the experiences of the new regulatory system, the system should be well established and moreover, it should be improved and enhanced in the future. Nuclear Industry and Safety Agency (NISA) is in charge of regulation of commercial nuclear facilities in Japan and decommissioning of them is included. Japan Nuclear Energy Safety Organization (JNES) is in charge of technical supports for NISA as a TSO (Technical Support Organization) also in this field. As for decommissioning, based on regulatory needs, JNES has been continuing research activities from October 2003, when JNES has been established. Considering the "Prioritized Nuclear Safety Research Plan (August 2009)" of the Nuclear Safety Commission of Japan and the situation of operators facilities, "Regulatory Support Research Plan between FY 2010-2014" was established in November 2009, which shows the present regulatory needs and a research program. This program consists of researches for 1. review process of decommissioning plan of power reactors, 2. review process of decommissioning plan of nuclear fuel cycle facilities, 3. termination of license at the end of decommissioning and 4. management of decommissioning waste. For the item 1, JNES studied safety assessment methods of dismantling, e.g. obtaining data and analysis of behavior of dust diffusion and risk assessment during decommissioning, which are useful findings for the review process. For the item 2, safety requirements for the decommissioning of nuclear fuel cycle facilities was compiled, which will be used in the future review. For the item 3, measuring method, release procedure and analysis code for the site release were studied for the establishment of the license termination process in the future. From FY 2010, based on the new plan, we have started the researches for the standardization of review process of decommissioning plan for power reactors and nuclear fuel cycle facilities, establishing the process and criteria of license termination and appropriate method of management of decommissioning waste based on the waste form confirmation process. © 2010 by ASME.