Abstract:Abstract: Aiming at the dynamic and static performance and lightweight design requirements of the fast reactor loader arm, the safety of the original structure was verified by finite element analysis. Solid isotropic microstructures with penalization (SIMP) of artificial materials method was proposed.Introducing the normalization coefficient,the dynamic and static multi-objective topology optimization mathematical model was established to combine the multi-condition stiffness and the dynamic key low-order frequencies into minimun combined compliance index,and the global Pareto solution was obtained. The results showed that the dynamic performance of the redesigned arm based on the topology optimization results increased greatly with a decreasing about 10% of maximum Tresca stress under SSE condition and a decreasing about 21.5% of weight,well meeting the structure optimization goal of improving performances and reducing weight .