The Effort for the nuclear material recovery from the reprocessing process and relevant
MC&A in the TRP Decommissioning Project

Tokai Reprocessing Plant (TRP) had reprocessed 1,140 tons spent fuel (SF) since 1977 to 2007, and the Post-Fukushima safety regulations triggered TRP to decide to shut the plant and shifted to decommissioning phase from 2018. The estimated entire duration of TRP decommissioning is expected to be 70 years. The early stage of the TRP decommissioning includes the recovery of remaining nuclear material in the process and transferring those nuclear material between multiple facilities(“Flushout”), vitrification activity of remaining high active liquid waste (HALW) and transferring collected nuclear material to the storage facility, and the management of radioactive waste. The Flush-out is as the first step of TRP decommissioning and it is in progress since June 2022 for two years prior to the start of serious decommissioning activities such as the decontamination, dismantling/removing the process. Since these decommissioning activities are unexperienced challenges and they are not related to “spent fuel reprocessing”, therefore ensuring appropriate nuclear material control and accountancy (MC&A) and the transparency in terms of safeguards verification implemented by International Atomic Energy Agency (IAEA) under ensuring the safety measure are important role as the operator. In this paper, we report about the residual nuclear material recovery process and relevant MC&A and safeguards measures in the Flush-out as the first stage of TRP decommissioning project.