DEVELOPMENT AND VALIDATION OF A SIMMER-III/ANSYS CODE CHAIN METHODOLOGY FOR THE INTEGRAL SAFETY ANALYSIS OF WCLL FUSION REACTOR COMPONENTS

In the framework of the development of fusion energy, one of the most prominent technologies arising to address the issues of tritium breeding and power conversion is the Water-Cooled Lithium-Lead (WCLL). This technology utilizes a molten eutectic alloy of Lithium and Lead which circulates inside the Breeding Blankets (BB) and is irradiated with neutrons to produce tritium. Water is then circulated inside the system to cool the components. The simultaneous presence inside critical areas of the reactor of molten metal alloys and water, at high temperature and pressure, poses significant safety concerns. For this reason, adequate design and analysis techniques are required to ensure the ability of the system to survive and mitigate any possible damage in case of the in-box Loss Of Coolant Accident (LOCA), the most critical postulated accidental scenario. This work introduces a new methodology for the integral safety analysis of WCLL components, with a particular focus on the WCLL Breeding Blankets, which is based on a fully automated code-chain technique. Its goal is to couple the calculations performed in the fluid domain by the SIMMER-III code, which models the chemical and thermodynamical interactions between the water and the alloy, and the structural simulations performed by the ANSYS code on the mechanical components. The entire process is validated against experimental data provided by the LIFUS5 facility operating at ENEA Brasimone Research Centre. The resulting comparison between these data and codes' predictions allows a careful evaluation of the errors introduced in each step of the chain. Moreover, it provides confidence in the capacity of the methodology to correctly predict the ability of the structures to withstand incidental loads without suffering extensive damage. This work aims at providing engineers with a usable and powerful tool that allows for the safety analysis of WCLL-based components during the early stages of the design phase. This would help save time, and effort and reduce the economic cost that might arise from any undetected issue propagating downstream the design process.