论文标题
低温颗粒的碎片分析减轻干扰
Fragmentation Analysis of Cryogenic Pellets for Disruption Mitigation
论文作者
论文摘要
像ITER这样的核融合反应器的生命周期和利用在很大程度上取决于其在干扰过程中减轻损害的能力。虽然选择了破碎的颗粒注射（SPI）作为ITER的基线缓解方法，但颗粒注射参数的确切关系和所得的片段分布尚不清楚。这种知识对于优化杂质沉积和缓解效率的杂物至关重要。在本论文中，我提出了170个SPI颗粒的碎片分析，重点是产生的碎片大小作为正常撞击速度的函数。这些实验是在德国Garching的Max Planck-Institute等离子体物理学（IPP）进行的，使用破碎的颗粒注入系统，该系统现已安装在ASDEX升级Tokamak上。与理论碎片模型的比较（Parks 2016）表明，该模型低估了直径低于0.9 mm的碎片量。同样，统计参数，例如平均片段大小和片段大小的标准偏差，似乎在实验中呈指数尺度，并在模型中线性线性地扩展。此外，我们发现，圆形粉碎几何形状引起的碎裂化不如矩形几何形状可再现，这可能与未来缓解系统中的设计选择有关。
The lifetime and utilization of a nuclear fusion reactor like ITER depends strongly on its capabilities to mitigate damage during disruptions. While shattered pellet injection (SPI) was chosen as the baseline mitigation method for ITER, the exact relation of pellet injection parameters and the resulting fragment distributions is not yet clear. This knowledge is of paramount importance for optimizing the impurity deposition and disruption mitigation efficiency. In this thesis, I present fragmentation analysis of 170 SPI pellets, with the focus on the produced fragment sizes as a function of normal impact velocity. The experiments were carried out at the Max Planck-Institute for Plasma Physics (IPP) in Garching, Germany, using the shattered pellet injection system that is now installed on the ASDEX Upgrade tokamak. Comparisons with a theoretical fragmentation model (Parks 2016) show that the model underestimates the amount of fragments below 0.9 mm in diameter. Also, statistical parameters such as the mean fragment size and the standard deviation of fragment size seem to scale exponentially in the experiment and linearly in the model. Furthermore, we found that the fragmentation induced by circular shattering geometries is less reproducible than for rectangular geometries, which might be relevant for design choices in future mitigation systems.
