A semi-quantitative risk assessment of remote handling operations on the SPES Front-End based on HAZOP-LOPA

This paper presents the Probabilistic Risk Assessment (PRA) developed for crucial components of the SPES (Selective Production of Exotic Species) nuclear facility, a research plant currently under construction at INFN's Legnaro National Laboratories. The study systematically analyzes the most serious failure scenarios of the SPES Front-End and the remote handling systems, with the aim of identifying critical issues and improving the systems in terms of operational safety, hardware design, robustness and reliability. The approach adopted in this study is a blended methodology based on semi-quantitative techniques. HAZOP (HAZard and OPerability analysis) and LOPA (Layer Of Protection Analysis) have been applied to evaluate the risk of failure scenarios during operation and to assess their consequences. This study identified some weaknesses in the system's design, leading to possible undesirable behaviors. A number of safeguards and recommendations have been proposed, as well as a selection of design improvements related to the robustness and maintainability of pivotal components. The results of this assessment support the validity of the proposed Independent Protection Layers (IPLs) adopted to ensure operational safety and optimize maintenance interventions in such highly radioactive environment.