Radioactive waste disposal14

High-level radioactive waste

In line with the Specified Radioactive Waste Final Disposal Act, final dis­posal facilities are planned for the geological disposal of HLW and are scheduled to start operation in the 2030s through the following three-step selection process: selection of preliminary investigation areas, selection of detailed investigation areas, and selection of the final disposal facility areas. When local governments wish to volunteer for ‘areas to be investigated as to the feasibility of constructing final repository of HLW’, it is important that the implementor (NUMO), the government and the utility companies give sufficient understanding and awareness to the local residents about the advantages and disadvantages of the final repository and various sectors of the local community, including local government. The government, research and development (R&D) institutions and NUMO, while giving due consid­eration to their own roles and in close partnership, are expected to consist­ently promote R&D into HLW geological disposal. NUMO is expected to safely implement the final HLW disposal project and systematically perform technical development to improve the economics and efficiency of the dis­posal activities. R&D institutions, led by the JAEA, through utilization of underground research facilities, continue to conduct research on under­ground geology, basic R&D towards improved reliability of geological disposal technology and safety assessment methods, and for safety regulations.

While being aware of overseas knowledge and experience, it is important to develop and maintain an advanced knowledge base that supports final repository projects and safety regulations, as well as to appropriately reflect it in NUMO’s final disposal projects. To this end, the government and R&D institutions work together to survey the entire Japanese waste management programme systematically and efficiently. R&D institutions such as JAEA, Radioactive Waste Management Funding and Research Center, etc., need to cooperate with the government and NUMO in activities to improve the understanding and awareness of society at large. Furthermore, it is neces­sary for the government to develop specific rules concerning safety regula­tions based on the progress of these R&D activities.

Geological disposal of radioactive wastes containing transuranium elements

Some LLW containing TRU elements needs to be disposed of geologically. If some TRU waste targeted for geological disposal can be buried together with HLW (co-disposed), the number of repository sites may be reduced, improving economic efficiency. Based on assessment of the influence of TRU and HLW co-disposal on the integrity of the disposal site, the govern­ment should then consider necessary measures, including the nature of an implementing body and its own involvement.

LLW from overseas reprocessing consigned by Japan will gradually be returned from France and the UK. French reprocessing firms suggest chang­ing the solidification method from embedding in bitumen to vitrification, while UK reprocessing companies will embed the LLW in cement for geo­logical or disposal with institutional control. In the latter case, the waste returned to Japan is HLW (vitrified waste) with equivalent levels of radio­activity to the LLW exported. In light of these suggestions, it is expected that the number of shipments can be reduced and storage facilities in Japan for LLW awaiting final disposal can be downsized. Thus, the government, in response to discussions with the operators, will assess the benefits of waste treatment by the new solidification methods, suggested by France, and of the conversion indexes of waste, as suggested by the UK. If these suggestions are found to be acceptable, the government should discuss the institutional issues.

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