Edge localized mode characteristics and divertor heat flux during stationary and transient phase for CFETR hybrid scenario
Edge localized mode characteristics and divertor heat flux during stationary and transient phase for CFETR hybrid scenario
复制标题
DOI：
10.1088/1361-6587/abd25d
复制
发表时间：
2020-12
影响因子：
2.2
通讯作者：
Zeyu Li;Yiren Zhu;Guoliang Xu;V. Chan;Xue-qiao Xu;Jiale Chen;R. Ding;T. Xia;X. Jian;Y. Zou;C. Xiao;Xiaogang Wang
中科院分区：
文献类型：
--
作者：
Zeyu Li;Yiren Zhu;Guoliang Xu;V. Chan;Xue-qiao Xu;Jiale Chen;R. Ding;T. Xia;X. Jian;Y. Zou;C. Xiao;Xiaogang Wang
针对中国聚变工程试验堆（CFETR）1GW混合模式运行方案（R = 7.2m，BT = 6.5T，Ip = 13.78MA），研究了边缘局域模（ELM）特性、稳态热流和瞬态热流。建模与仿真从一个场景出发，在一个建模框架下进行多代码集成建模，得到一个集成任务框架。利用BOUT++六场简化磁流体动力学模块对ELM动力学进行了线性稳定性和非线性模拟，结果表明ELM的能量损失（ΔELM ~ 0.13%）远小于I型ELM。弱线性增长率和小ELM能量损失特性的参数分析揭示了对应于CFETR 1 GW混合场景的草ELM制度的物理。使用BOUT++研究了在这个小ELM阶段偏滤器靶上的瞬态热通量。我们发现，上游径向输送的刮落层（SOL）小ELMs诱导的是弱的，这使得它在漂移为主的区域。然而，在ELM非线性演化过程中，随着分界线温度的升高，热流宽度仍然加宽至λq = 4.64 mm。首次利用连接基座和SOL的基于物理的输运方法评估了瞬态峰值热负荷和ELM能量注量对偏滤器靶钨熔化和净侵蚀率的影响。单个ELM脉冲引起的能量注量低于钨熔化极限，而钨侵蚀将超过材料要求。我们的结论是外部缓解方法，如偏滤器分离和先进的偏滤器几何结构可能需要CFETR的稳态运行。
The study of edge localized mode (ELM) behavior, stationary heat flux and transient heat flux during the ELM crash phase is performed for a China Fusion Engineering Test Reactor (CFETR) 1 GW hybrid mode operation scenario ( R = 7.2 m, BT = 6.5 T, Ip = 13.78 MA). Modeling and simulation start with a scenario obtained by multi-code integrated modeling on the one modeling framework for integrated tasks framework. Linear stability and nonlinear simulations of ELM dynamics are carried out using the BOUT++ six-field reduced magnetohydrodynamic module, which show a much smaller ELM energy loss (ΔELM ~ 0.13%) compared to that of a Type-I ELM. Parametric analysis of the weak linear growth rate and small ELM energy loss characteristics shed light on physics corresponding to a grassy ELM regime for CFETR 1 GW hybrid scenario. The transient heat flux on the divertor target during this small ELM phase is investigated using BOUT++. We found that upstream radial transport in the scrape-off-layer (SOL) induced by small ELMs is weak, which keeps it in the drift-dominated region. However, the heat flux width is still broadened to λq = 4.64 mm by the increase of separatrix temperature during ELM nonlinear evolution. The impact of transient peak heat load and ELM energy fluence on tungsten melting and net erosion rate of divertor target is evaluated for the first-time using physics-based transport that connects the pedestal with the SOL. Energy fluence caused by a single ELM pulse is below the tungsten melting limit, while tungsten erosion would exceed the material requirements. We conclude that external mitigation methods, such as divertor detachment and advanced divertor geometry are likely needed for the steady state operation of CFETR.