Shutdown dose rate assessment for a DCLL blanket-based reactor: Application of the R2S-UNED approach

Under the Spanish Breeding Blanket Technology Programme TECNO_FUS a conceptual design of a DCLL (Dual-Coolant Lithium–Lead) blanket for a DEMO is being revisited. In this work shutdown dose rates (SDR) for in-vessel and ex-vessel regions are calculated for maintenance purposes under a commercial irradiation scenario. In addition to absorbed dose rates in specific materials relevant for RH equipment, biological dose for potential workers access is also computed. Information regarding SDR spatial distributions and time evolution, contribution of the different activated structural materials of the blanket and the vacuum vessel (VV), and critical isotopes are provided. For these SDR calculations our Rigorous Two Step (R2S) mesh based approach, R2S-UNED, has been used.