Design Optimization And Transient Safety Analysis Of The First Wall For CFETR HCSB

The breeder blanket in a fusion DEMO reactor is a key functional component. It is designed to contain plasma, deposit and transform fusion energy and breed tritium. The blanket installed in CFETR is now being developed as Chinese Fusion Engineering Testing Reactor project proceeding by china independently. Helium Cooled Ceramic breeder Blanket is widely developed since the concept has many advantages such as stable structure, nice material compatibility and no MHD effect which may perplexes liquid metal blanket. Most of the radiation heat and neutrons from high-temperature plasma is endured by first wall (FW) as an important safety part of blanket structure. It has important research significance for improve the structural reliability and security to analyze thermal mechanical performance, optimize the dimensions of cooling channel and verify its safety features in the accident condition.First, numerical simulation of the first wall in a recently proposed Helium Cooled Ceramic breeder Blanket concept was carried out by one-way fluid-structure interaction to analyze its thermal and mechanical performance. Based on the independence and the quality of mesh, temperature and stress field of the FW under normal condition were calculated. The results showed that the temperature exceeded the material temperature limit. Although the total stress was satisfied3Sm rules in Structure Design Criterion (SDC) used by ITER, the thermal stress was far beyond the design requirement. So optimization of FW structure was needed.The optimization of cooling channel considered three main factors:cross-section area, interval between adjacent channels and corner radius. To solve the problem of stress concentration at the bend of FW, different inner radius of the bend were analyzed. Comparing the maximum temperature, maximum stress and coolant hydraulic pressure drop of different structure, an optimization scheme was suggested:9×9mm2cross-section area,5mm interval between adjacent channels,3mm corner radius, and80mm inner radius of the bend. The thermal mechanical analysis of optimized FW demonstrated that the maximum temperature decreased by49%, and the total stress dropped by33%. Design requirement was satisfied finally. Finally, three reference events of blanket module given from ITER, including in-vessel LOCA, in-box LOCA and ex-vessel LOCA were analyzed assuming that the coolant is totally lost in the accidents. The transient temperature evolution of blanket module was calculated using ANSYS. The safety features of the FW were focused on.