Modelling of the effect of ELMs on fuel retention at the bulk W divertor of JET

• Main Authors: K. Heinola, T. Ahlgren, S. Brezinsek, T. Vuoriheimo, S. Wiesen
• Format: Article
• Language: English
• Published: Elsevier 2019-05-01
• Series: Nuclear Materials and Energy
• Online Access: http://www.sciencedirect.com/science/article/pii/S2352179118301868

Effect of ELMs on fuel retention at the bulk W target of JET ITER-Like Wall was studied with multi-scale calculations. Plasma input parameters were taken from ELMy H-mode plasma experiment. The energetic intra-ELM fuel particles get implanted and create near-surface defects up to depths of few tens of nm, which act as the main fuel trapping sites during ELMs. Clustering of implantation-induced vacancies were found to take place. The incoming flux of inter-ELM plasma particles increases the different filling levels of trapped fuel in defects. The temperature increase of the W target during the pulse increases the fuel detrapping rate. The inter-ELM fuel particle flux refills the partially emptied trapping sites and fills new sites. This leads to a competing effect on the retention and release rates of the implanted particles. At high temperatures the main retention appeared in larger vacancy clusters due to increased clustering rate. Keywords: ELM, Fuel retention, Multi-scale computing, JET