The ITER vertical stabilization coil system is designed to provide fast plasma stabilization in all scenarios with elongated plasma cross-section. It consists of two water-cooled coils located in upper and lower portions of the vacuum vessel (VV), with feedthroughs responsible for the transfer of electricity and cooling water across the vacuum boundary of VV. Depending on location, the feedthroughs can be divided into upper port feedthroughs (UPR feedthroughs) and lower port feedthroughs (LWR feedthroughs), each family sharing the same design. Both designs are subject to demanding operation scheme, a severe working environment and the presence of interfacing components, which impose important thermal, electromagnetic and seismic loads on the components. In particular, the LWR feedthrough, object of present paper, is more impacted by seismic loads due to the more flexible structure compared to the UPR feedthrough. During the worst seismic event, it is subjected to a vertical acceleration of 28.8ms⁻², acting on an effective mass of 249.9kg at its first order modal mode. Furthermore, the current circulating in the conductor of the LWR feedthrough, impose significant linear forces, up to 27.7kNm⁻¹ during normal operation and 30.3kNm⁻¹ during categories I & II abnormal plasma events, respectively. Finally, the effect of differential thermal expansions of interfacing structures imposes a relative displacement between the supports up to 32.9mm in X (radial) direction and up to 14.67mm in Z (vertical) direction, during baking. Being part of the vacuum boundary, the feedthrough must assure confinement function under all normal and accidental loading conditions, with proper structural integrity assessment by applying analysis approach and design criteria foreseen by the applicable nuclear codes. The paper details the load types and categories, the analysis methodologies, the structural design criteria, and the assessment results in views of static stress and fatigue for the LWR feedthrough. This study could be a comprehensive reference for the structural integrity assessment of other similar components in fusion devices.

ITER垂直稳定线圈系统旨在在所有具有细长等离子体横截面的情况下提供快速等离子体稳定。它由两个位于真空容器（VV）上部和下部的水冷线圈组成，带有贯穿件，负责通过VV真空边界传递电和冷却水。根据位置的不同，馈通可以分为上部端口馈通（UPR馈通）和下部端口馈通（LWR馈通），每个系列都采用相同的设计。两种设计都必须遵守苛刻的操作方案，恶劣的工作环境以及存在​​接口组件，这对组件施加了重要的热，电磁和地震载荷。特别是LWR馈线，即本文的目标，与UPR馈通相比，由于结构更加灵活，因此受到地震载荷的影响更大。在最严重的地震事件中，它受到28.8ms的垂直加速度^-2，在一阶模态下作用于249.9kg的有效质量。此外，在馈通LWR的导体中循环的电流，施加显著线性力，高达27.7kNm ^-1正常运行和30.3kNm期间^-1分别I＆II等离子体异常事件，类别中。最后，界面结构的不同热膨胀效应会导致支撑件之间在X（径向）方向上的相对位移最大为32.9mm，在Z方向上的最大位移为14.67mm。（垂直）方向，在烘焙过程中。作为真空边界的一部分，馈通必须确保在所有正常和意外载荷条件下的限制功能，并通过应用适用的核规范所预见的分析方法和设计标准，对结构进行完整性评估。本文详细介绍了轻水堆贯穿件的静应力和疲劳状况，分析了载荷类型和类别，分析方法，结构设计标准以及评估结果。这项研究可以为融合装置中其他类似组件的结构完整性评估提供全面的参考。