A RAMI analysis of the neutron activation system (NAS) for the HCCP-TBM

The Neutron Activation System (NAS) is a vital diagnostic component of the Helium-Cooled Ceramic Pebble (HCCP) Test Blanket Module (TBM) under development for the ITER project. This study presents the first detailed RAMI (Reliability, Availability, Maintainability, and Inspectability) analysis specifically applied to the NAS, aiming to ensure it can reliably measure neutron flux and spectrum to support tritium breeding validation and efficiency. By evaluating potential failure modes and their impacts, the analysis identified critical components with high risk, such as the disposal bin, vacuum pump, capsule loader, and transfer station. To address these issues, targeted mitigation strategies, including design improvements and enhanced maintenance protocols, were proposed, which effectively reduced the criticality levels of these components. The study also emphasized the importance of spare parts optimization and proactive maintenance to maintain high system availability over a projected 20-year operation. The results underscore the importance of integrating RAMI analysis in the early design phase to identify and mitigate risks, thereby ensuring long-term stability and reliability of diagnostic systems like the NAS in fusion energy applications.