Dust generation in tokamaks: Overview of beryllium and tungsten dust characterisation in JET with the ITER-like wall
Dust generation in tokamaks: Overview of beryllium and tungsten dust characterisation in JET with the ITER-like wall
复制标题
DOI：
10.1016/j.fusengdes.2018.03.027
复制
发表时间：
2018-11-01
影响因子：
1.7
通讯作者：
Zychor, I.
中科院分区：
文献类型：
--
作者：
Rubel, M.;Widdowson, A.;Zychor, I.
具有铍和钨类ITER壁的JET托卡马克的运行为详细研究尘埃生成：数量、形态、位置等提供了独特的机会。为响应ITER安全评估的需要而开展的方案包括：（一）对偏滤器进行遥控真空清洁;（二）对面向等离子体的部件（PFC）中松散结合的物质进行局部取样;用偏滤器和主室中的各种侵蚀-沉积探针收集流动的尘埃。通过许多补充技术（例如，一系列显微镜方法、电子和离子光谱、液体色谱法和热解吸）进行的综合分析的结果总结如下：（a）在三次活动之后，通过真空清洁收集的灰尘的总量为每次活动约1-1.4 g（19.1-23.5小时等离子体操作），即，比用碳壁操作的JET（即JET-C）小100倍以上。(b)被确定为两个主要类别的灰尘：PFC和液滴（直径2-10微米）上形成的共同沉积物的薄片。少量的，低于1克，铍液滴和飞溅主要与铍限制剂的熔化。(c)钨粉尘主要以部分熔融的薄片形式出现，这些薄片来自涂W的瓷砖。
Operation of the JET tokamak with beryllium and tungsten ITER-like wall provides unique opportunity for detailed studies on dust generation: quantity, morphology, location, etc. The programme carried out in response to ITER needs for safety assessment comprises: (i) remotely controlled vacuum cleaning of the divertor; (ii) local sampling of loosely bound matter from plasma-facing components (PFC); (iii) collection of mobilized dust on various erosion-deposition probes located in the divertor and in the main chamber. Results of comprehensive analyses performed by a number of complementary techniques, e.g. a range of microscopy methods, electron and ion spectroscopy, liquid scintillography and thermal desorption, are summarized by following points:(a) Total amount of dust collected by vacuum cleaning after three campaigns is about 1-1.4 g per campaign (19.1-23.5 h plasma operation), i.e. over 100 times smaller than in JET operated with carbon walls (i.e. in JET-C).(b) Two major categories of Be dust are identified: flakes of co-deposits formed on PFC and droplets (2-10 mu m in diameter). Small quantifies, below 1 g, of Be droplets and splashes are associated mainly with melting of beryllium limiters.(c) Tungsten dust occurs mainly as partly molten flakes originating from the W-coated tiles.