Optimizing Radiation Shielding for Fusion Maintenance Facilities: Insights From a Comprehensive Analysis of ITER Hot Cell

One of the primary goals of the ITER project is to demonstrate the safety characteristics of a fusion device, particularly in terms of radiation management. Radiation protection during maintenance periods is of special concern, as personnel performing maintenance-like activities will be exposed to delayed gamma fields from numerous and complex radioactive components. Ensuring a safe and equipped environment for such activities is the objective of the ITER hot cell. This facility requires extensive design optimization, balancing spatial and temporal availability constraints, radiation protection, and cost-effectiveness. In this paper, we present a comprehensive assessment of ITER hot cell’s radiation environment to support its efficient design and safe operation. The study evaluates the shielding efficiency of the conceptual design layout from 2021, providing meaningful insights for layout improvement. We show that substantial amounts of concrete (~2900 m³) could be saved from the currently evolving design while respecting radiological requirements. The evaluation of the occupational radiation exposure (ORE) associated with hot cell maintenance activities resulted in 179 man·mSv·year⁻¹, which represents a significant fraction (36%) of the project’s annual budget. This highlights the importance of integrating shielding analysis, accounting for personnel radiation exposure, even in early design phases, to support the optimization of the maintenance plan according to safety requirements.