Tritium self-sufficiency presents a critical engineering challenge for DEMO, requiring efficient breeding and extraction systems, as well as minimizing tritium losses to the surrounding systems, such as plasma-facing components, vacuum vessel, cooling system, etc. Structural and plasma-facing components will act as a tritium sink, as tritium will be accumulated in the bulk of these components due to energetic particle bombardment and may permeate out of the vacuum system. The design of the plasma-facing components will consequently directly influence the plant lifetime, operational safety and cost of any future power plant. Therefore, modeling of tritium retention and permeation in these components is required for the engineering designs of the tritium breeding and safety systems. In this work, the diffusion-transport code TESSIM-X is benchmarked against the well-established TMAP7 code and a comparison with a simplified DEMO-relevant test case is performed. The use of either code for modeling of DEMO conditions is discussed. Following this, TESSIM-X is used to provide a preliminary assessment of tritium permeation and retention in the DEMO first wall, based on the current WCLL (Water Cooled Lithium Lead) and HCPB (Helium Cooled Pebble Bed) breeding blanket designs.

氚自给自足对 DEMO 提出了关键的工程挑战，需要高效的育种和提取系统，以及尽量减少氚对周围系统的损失，例如面向等离子体的组件、真空容器、冷却系统等。 结构和面向等离子体组件将充当氚吸收器，因为高能粒子轰击会在这些组件的大部分中积累氚，并可能从真空系统中渗出。因此，面向等离子体的组件的设计将直接影响任何未来电厂的寿命、运行安全性和成本。因此，氚育种和安全系统的工程设计需要对这些组件中的氚保留和渗透进行建模。在这项工作中，扩散传输代码 TESSIM-X 与完善的 TMAP7 代码进行了基准测试，并与简化的 DEMO 相关测试用例进行了比较。讨论了使用任一代码对 DEMO 条件进行建模。在此之后，基于当前的 WCLL（水冷锂铅）和 HCPB（氦冷却球床）育种毯设计，TESSIM-X 用于提供对 DEMO 第一壁中氚渗透和保留的初步评估。