Characterization of in situ damage to tungsten PFCs induced by transient heat flux during plasma disruption in EAST

作者：Chuannan Xuan, Dahuan Zhu, Yang Wang, Binfu Gao, Wenxue Fu, Zongxiao Guo, Rui Ding, Baoguo Wang, Pengfei Zi, Junling Chen, the EAST Team · 发表于：Nuclear Fusion · 年份：2025 · DOI：10.1088/1741-4326/adc1e0 · 被引用次数：5 · 研究领域：Fusion materials and technologies、Nuclear Materials and Properties、Nuclear reactor physics and engineering

Abstract Transient heat flux of up to several thousand MW m −2 in a short pulse (∼ms) in tokamaks poses great risk to plasma-facing components (PFCs), making it a major concern for ITER. Despite numerous high heat flux tests, analysis of in situ transient heat flux-induced damage to PFCs remains necessary. Such damage, including the melting and cracking of tungsten (W) PFCs, is notably observed on the divertor (dome and baffle plates) and limiter in EAST. The damage is identified as being induced by runaway electron loss during plasma disruption at the beginning of each plasma campaign. It typically occurs at the leading edges or protruding parts of PFCs, sometimes accompanied by visible macrocracks. In terms of melting phenomena, three distinct grain layers can be observed from the molten surface to deeper regions, namely columnar grain, equiaxed grain (recrystallization region) and original grain. This grain distribution indicates a steep temperature gradient from the surface to the deeper regions during melting events, a characteristic feature for W under fusion-relevant transient heat flux loading. The surface morphologies of all melted PFCs are generally similar, characterized by undulated melting waves. The motion of the melting layer is primarily along the toroidal direction, as shown in the in situ melting of PFCs. The influence of the J × B force might not be significant due to the limited lifetime of the melting pool, which results in limited acceleration times and ...