Feasibility study on the DFP adoption of medical cyclotron decommissioning in the Republic of Korea

Since the development of positron emission tomography in 1937, the number of medical cyclotrons used in producing radioisotopes (RI) has risen sharply. In its operation, the structural materials of a medical cyclotron and the concrete shielding of its vault are activated by neutrons. In analyzing domestic and international decommissioning practices, the dismantling characteristics of medical cyclotrons result in a large amount of radioactive wastes, such as concrete, although their activity level is very low. In the United States, the dismantling plan must be established by the applicant. The decommissioning funding plan (DFP) is a financial assurance demonstration based on a site-specific cost estimate of decommissioning the facility. In 10 CFR 30.35, NRC requires the submission of DFP in the case of the possession and use of unsealed byproduct materials with a half-life of greater than 120 days and in quantities exceeding 10(5) times that of the applicable quantities. The dismanding of the Seoul National University Hospital (SNUH) cyclotron (TR-13) was performed in December 2012. Some of the risks resulting from this dismantling are related to radioactive wastes, as well as issues concerning dismantling costs. Hence, we propose introducing the DFP at the authorization stage. DFP will be helpful in preparing reliable decommissioning plans for safe decommissioning and unexpected early decommissioning in the future. DFP can also contribute in reducing radioactive waste and in decreasing the decommissioning cost by preventing excessive establishments. This study provided an overview of the decommissioning aspects of the SNUH cyclotron and the necessity of adopting the DFP for decommissioning medical cyclotrons.