Abstract Within the framework of EUROfusion DEMO First Wall and limiter design activities, the protection of the First Wall against power deposition peaks is being considered. During steady-state operation, the radiative power from the plasma could be considered more uniformly spread on plasma-facing components than the charged particle power deposition. The presence of openings (i.e. gaps between segments and ports) and the introduction of limiters breaks the continuity of the wall and opens the possibility of localized high heat flux values on toroidal-facing gaps due to charged particles striking the wall. The heat flux pattern is likely to be altered by misalignments between components due to manufacturing, assembly or non-uniform/non-symmetrical operational conditions in the segments. In this paper, the 3D field line tracing code SMARDDA is used for studying the impact of misalignment on the heat load distribution for a periodically segmented DEMO First Wall, specifically the Single Module Segment Concept. The present work does not address any study on limiter misalignments, which will be treated separately. The work covers normal operation conditions (ramp-up and steady-state), considering both the cases of bare First Wall (without limiters, as reference) and First Wall protected by limiters. The main aim of the work is understanding how the power deposition on the First Wall (due to charged particles) is affected by the presence of a radial or vertical misalignment between segments and starting a workflow to be applied later to all the possible plasma scenarios and First Wall layout. Heat flux penalty factor maps have been created to identify the worst cases among the ones analyzed. The related heat flux maps are relevant for thermal assessments of a simplified DEMO model to be performed later on, particularly in terms of maximum temperature values for the current DEMO design.

中文翻译：

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裸露和限制器 DEMO 单模块段概念首次通过 3D 场线追踪研究壁面错位

摘要 在 EUROfusion DEMO 第一壁和限制器设计活动的框架内，正在考虑保护第一壁免受功率沉积峰值的影响。在稳态操作期间，可以认为来自等离子体的辐射功率比带电粒子功率沉积更均匀地分布在面向等离子体的组件上。开口（即段和端口之间的间隙）的存在和限制器的引入破坏了壁的连续性，并打开了由于带电粒子撞击壁而导致面向环形间隙的局部高热通量值的可能性。由于制造、组装或分段中的非均匀/非对称操作条件，部件之间的未对准可能会改变热通量模式。在本文中，3D 场线追踪代码 SMARDDA 用于研究错位对周期性分段 DEMO First Wall 的热负荷分布的影响，特别是单模块分段概念。目前的工作不涉及任何关于限制器未对准的研究，将单独处理。工作涵盖正常操作条件（加速和稳态），同时考虑裸露的 First Wall（无限制器，作为参考）和受限制器保护的 First Wall 的情况。这项工作的主要目的是了解第一壁上的功率沉积（由于带电粒子）如何受到段之间存在的径向或垂直错位的影响，并开始一个工作流程，以便稍后应用于所有可能的等离子体场景和第一面墙布置。已创建热通量惩罚因子图以识别所分析的最坏情况。相关的热通量图与稍后要执行的简化 DEMO 模型的热评估相关，特别是在当前 DEMO 设计的最高温度值方面。