The charged particle heat load expected for the DEMO Single Module Segment first wall (FW) during current off-normal plasma scenarios indicates that protection is needed for avoiding/reducing damage to the breeding blanket FW due to the deposition of a huge amount of energy in a small timescale [1].

Within the EUROfusion framework of heat load analysis and design of DEMO wall and FW protections during plasma transients (identified as “Key Design Integration Issue 1” [2]), extensive reworking has led to FW and limiter designs that keep the flat-top maximum heat load on both the FW and limiter plasma-facing surfaces within engineering limits. The limiter strategy appears promising for both normal and off-normal plasma events, therefore the study will be focussed on a FW equipped with limiters.

As a continuation of the work started in [3], which has highlighted the weakest point of the older FW design and led to the new FW layout, the impact of misaligned segments and limiters on the charged particle heat flux pattern is investigated for the “limited” FW (i.e. FW protected by limiters). The study is carried out by 3D field line tracing codes SMARDDA/PFCflux [4], [5] and covers normal operation scenarios (ramp-up and steady-state) with the aim of producing heat flux penalty factor distribution to identify the worst case scenarios. As far as the normal transient events are concerned, the results in [3] are updated. In addition, during steady-state operation, deformation of in-vessel components due to mechanical loads such as ferromagnetic forces acting on EUROfer and different thermal expansion of adjacent segments, leads to the exposure of edges that are shadowed in the FW undeformed configuration. As a novel approach, flexible geometrical transformations simulating this kind of normal operation misalignment are implemented for studying the impact on the charged particle heat load of the induced differential deformations.

在当前非正常等离子体情况下，DEMO单模块段第一壁（FW）的带电粒子热负荷预期表明需要保护以避免/减少对繁殖毯FW的损坏，因为在其中沉积了大量能量较小的时间范围[1]。

在EUROfusion框架的热负荷分析以及等离子瞬变期间设计的DEMO壁和FW保护装置（标识为“关键设计集成问题1” [2]）中，广泛的返工导致FW和限制器设计保持了平顶最大在工程极限范围内，FW和限流器面向等离子体的表面上的热负荷。对于正常和非正常血浆事件，限幅器策略似乎很有希望，因此，本研究将集中在配备限幅器的FW上。

作为[3]中工作的延续，该工作突显了旧的FW设计的最薄弱之处，并导致了新的FW布局，针对“有限”固件（即由限制器保护的固件）。该研究是通过3D场线跟踪代码SMARDDA / PFCflux [4]，[5]进行的，涵盖了正常运行场景（加速和稳态），目的是产生热通量损失因子分布以识别最坏情况。场景。就正常的瞬态事件而言，[3]中的结果被更新。此外，在稳态操作期间，由于机械载荷（例如作用在EUROfer上的铁磁力以及相邻段的不同热膨胀）导致的在车部件的变形，导致暴露在FW未变形配置中阴影的边缘。作为一种新颖的方法，实现了模拟这种正常操作未对准的灵活几何变换，以研究引起的微分变形对带电粒子热负荷的影响。