Structural Integrity Assessment of ITER Torus Cryo-Pump Housing

Abstract

In this article, a structural integrity assessment of ITER Torus Cryo-Pump Housing (TCPH) is presented. TCPH is a penetration structure located on the cryostat cylinder whose main function is to accommodate and support the Torus Cryo-Pump (TCP), connect it to the vacuum vessel (VV), and provide tritium confinement and primary vacuum boundary. The design of the TCPH structure was finalized during the final design review (FDR). After the FDR, based on the manufacturing feasibility study, changes in the design were proposed to facilitate the nondestructive examination of weld joints. To qualify the proposed changes, structural integrity assessment was performed as per Section VIII Div. 2 Part 5 of ASME code by finite-element analysis using ANSYS software. The structural and thermal assessment was done as per TCPH load specification for protection against plastic collapse, local failure, ratcheting, buckling, and fatigue to perform the structural integrity of the TCPH. The results obtained from the integrity assessment qualified the design criteria. Margins available over allowable stress values for plastic collapse, local failure, and ratcheting are 20%, 19%, and 30%, respectively. A buckling factor of 79 was achieved with a minimum allowable value of 13.42. For fatigue, a usage fraction of 0.516 was obtained against allowable maximum value of 1. Thus, the design with proposed changes was qualified and incorporated.