Accidental transients in fusion reactors, such as the in-vessel loss-of-coolant accident (LOCA) considered here, are generally analyzed using system-level codes. However, because of their lumped nature, such tools cannot predict local pressure and temperature values, which are instead of interest to assess the integrity of the vacuum vessel (VV) structures. It is then fundamental to prove that the system-level tools’ predictions are at least conservative. In this work, we analyze the helium flow inside the VV following a LOCA in the helium-cooled blanket of the EU DEMO, using a 3D transient computational fluid-dynamics (CFD) model implemented in the commercial STAR-CCM+ code. In view of the large pressure ratio, a hypersonic flow regime (Ma > 5) develops, with the formation of shock fronts requiring a high time and space resolution. The model is applied to compute the evolution of the pressure distribution inside the VV and then to compare it with the information provided by the system-level GETTHEM model. The predictions by the two models of the intervention time of the VV pressure suppression system are compared, showing that the 0D model is conservative.

通常使用系统级代码来分析聚变反应堆中的意外瞬变，例如此处考虑的船内冷却液损失事故（LOCA）。但是，由于这些工具集总的性质，因此它们无法预测局部压力和温度值，这对于评估真空容器（VV）结构的完整性是不重要的。然后，必须证明系统级工具的预测至少是保守的。在这项工作中，我们使用在商业STAR-CCM +代码中实现的3D瞬态计算流体动力学（CFD）模型，分析了EU DEMO氦气冷却毯中LOCA之后VV内部的氦气流动。鉴于大的压力比，高超音速流态（Ma> 5）发展，并形成了需要高时空分辨率的激波锋面。该模型用于计算VV内部压力分布的演变，然后将其与系统级GETTHEM模型提供的信息进行比较。比较了两种模型对VV压力抑制系统干预时间的预测，表明0D模型是保守的。