DEMO is a key part of the EU fusion roadmap, and the programme reaches the end of the pre-conceptual phase with a gate review in 2020. As part of the work to complete this phase, eight Key Design Integration Issues (KDII’s) have been identified as critical to the programme. Two of these KDII’s identified a requirement for a more detailed architectural study. Within KDII#3 (advanced divertor configurations) a double null configuration has been developed; in parallel KDII#4 (vertical segment architecture) identified a need to evaluate a split breeding blanket architecture. These two requirements were combined into a single study that assesses the in-vessel architecture for a double null DEMO featuring split breeding blankets.

This paper presents the configurations developed and an evaluation of their feasibility with respect to integration of key in-vessel components (breeding blankets, divertors), port hardware (service pipes, shielding, vacuum pumping), and maintenance strategy. Furthermore, wider considerations such as the impact of the port orientation on the building architecture are also included. Finally, this paper will identify the risks and further work required to advance the double null configuration.

DEMO是欧盟融合路线图的重要组成部分，该计划已进入概念前阶段的最后阶段，并于2020年进行了审查。作为完成此阶段工作的一部分，已完成了八个关键设计集成问题（KDII）。被确定为对该计划至关重要。这些KDII中有两个确定了进行更详细的体系结构研究的要求。在KDII＃3（先进的偏滤器配置）中，已经开发了一个双空配置。并行KDII＃4（垂直段架构）确定需要评估拆分育种毯架构。将这两个要求组合到一个研究中，该研究评估了具有分离育种毯的双重无效DEMO的容器结构。

本文介绍了开发的配置并评估了其在集成关键车载组件（育种毯，分流器），端口硬件（服务管道，屏蔽，真空泵）和维护策略方面的可行性。此外，还包括更广泛的考虑因素，例如端口方向对建筑结构的影响。最后，本文将确定风险和进一步推进双重无效配置所需的工作。