Design Optimization of the Interim Support of the ITER Lower Cryostat Thermal Shield Using a Metamodel

The ITER lower cryostat thermal shield (LCTS) is fixed to the cryostat floor by thin flexible plate supports made of titanium alloy. A 500-mm high and 12-mm thick plate support is adopted as a reference design. However, design optimization is requested to save manufacturing costs, because the titanium alloy is expensive to fabricate. In addition to the reduction in mass, a design study was performed by using stainless steel as an alternative material for better manufacturability. This paper describes the design process to find an optimal design of the interim support of the LCTS. The sensitivity of the design variables, such as thickness, height, and width of the plates, is investigated. The optimal design is obtained by a sequential quadratic programming algorithm based on a metamodel developed by randomly selected experimental samples. Through the design optimization process, the optimal design of the interim support of the LCTS support is obtained.