Total ionizing dose estimation of ITER upper port remote handling equipment

This study delineates a comprehensive estimation of the integrated Total Ionizing Dose (TID) for the ITER Upper Port Remote Handling Equipment (UPRHE). The primary objective is to assess the radiation impact and devise strategies to attenuate its effects on the UPRHE components. Radiation levels in various operational zones are deduced from the ITER radiation map. This analysis includes a meticulous definition of operation sequences and corresponding durations for each maintenance task executed by the UPRHE. It is imperative to evaluate each subsystem of the UPRHE for its resilience against the maximum conceivable dose rate and the cumulative TID throughout its operational lifespan. The estimation of TID for the UPRHE encompasses both hourly rates and cumulative doses, calculated based on the identified dose levels and task durations. Additionally, this study computes the TID for all UPRHE subsystems over both a single long-term maintenance (LTM) cycle and the projected 20-year lifespan. Subsequently, the study justifies the derived TID values with the established nuclear radiation alert thresholds for ITER electronics. This comparison reveals that most UPRHE components remain within the safety margin. For components surpassing these thresholds, the paper proposes mitigation strategies to refine the system design in subsequent development phases.