External costs of material recycling strategies for fusion power plants

This study was performed within the framework of the Socio-Economic Research on Fusion project (SERF3), which is jointly conducted by Euratom and the fusion associations. Assess-ments of monetarized external impacts of the fusion fuel cycle were performed previously (SERF1 and SERF2). In this study, several fusion power plant designs (SEAFP Models 1-6) were compared focus-ing on a part of the plant's life cycle: environmental impact of recycling the materials. The models differ mainly by the type materials used for core reactor components and type of cooling medium. Recycling is considered for materials replaced during normal operation, as well as materials from decommissioning of the plant. Several recycling schemes for activated parts have been suggested, one of which proposes using recycled fusion compo-nents when building new fusion reactors. Environmental impact was assessed and expressed as external costs normalised with the total electrical energy output during plants operation. This facilitates comparison with other options for electricity generation. The methodology used for this study was developed by the Commission of the European Union within the frame of the "ExternE" project. It is a bottom-up methodology, with a marginal and site specific approach. Quantification of impacts is achieved through the damage function or impact pathway approach that follows the sequence of events linking a burden to an impact and subsequent monetary valuation. This means that it involves siting a power plant, and calculating its contribution to the environ-mental and health situation locally, regionally and globally. Different material streams were used for activated recyclable parts and "common" recyclable parts. The regulations regarding transports and handling of radioactive materials will govern how they are treated. Some components will be possible to recycle only after up to 100 years of cooling, during which it must be stored. Even after that, some parts may have to be taken to final repositories. This amount varies between designs. The external costs of different scenarios for managing used fusion plant materials can be used as a contribution to the basis for decisions regarding waste from fusion plants.