Design optimization using kriging metamodel for the ITER Lower Cryoat Thermal Shield support

Abstract

ITER Lower Cryostat Thermal Shield (LCTS) is fixed to the cryostat floor by thin flexible plate support made from titanium alloy. Thin plate with titanium alloy has good flexibility to the thermal movement and reduces conduction heat load from cryostat floor to the thermal shield. Titanium alloy requires high cost for fabrication. Design optimization is requested to save manufacturing expenses. In addition to the mass minimization, design study is investigated by using stainless steel as an alternative material for better manufacturability. In this paper, design process to find optimal design of interim support for the LCTS is described. The sensitivities of the design-variables such as thickness, height and width of the plates are investigated. Optimal design solution is obtained by Sequential Quadratic Programming (SQP) algorithm based on the meta-model developed by randomly selected experimental samples. Through the design optimization process, optimal designs, of the interim support of LCTS support are obtained.