Radiation dose analysis in the lithium system rooms during beam-on and beam-off

International Fusion Materials Irradiation Facility – DEMO-Oriented NEutron Source (IFMIF-DONES) is a d–Li neutron irradiation facility developed, which is being designed as part of the European roadmap to fusion-generated electricity. This work presents shielding analyses to support the design of the Test Cell floor and the safety assessment of lithium system rooms under beam-on and beam-off conditions. A detailed MCNP model of the Lithium Loop Cells (LLC) room, including the new Dump Tank baseline, Heat Exchanger, and electromagnetic pumps, has been developed and integrated into the main building model. The model includes the shielding barrier configuration and relevant piping. Shielding calculations are performed to estimate the required thicknesses of the cover and wall, considering space limitations in the LLC and the use of different materials, such as ordinary and heavy concrete. In addition, the radiation dose in the LLC is re-evaluated using updated Activated Corrosion Product (ACP) source terms. The results provide updated dose maps to support maintenance planning and safety assessment of the lithium systems.