Coated boron layers by boronization and a real-time boron coating using an impurity powder dropper in the LHD  

作　　者：Naoko ASHIKAWA Robert LUNSFORD Federico NESPOLI Erik GILSON Yaowei YU Jiansheng HU Shinichiro KADO 

机构地区：[1]National Institute for Fusion Science,Toki 509-5292,Japan [2]Princeton Plasma Physics Laboratory,Princeton NJ 08540,United States of America [3]Institute of Plasma Physics,Chinese Academy of Sciences,Hefei 230031,People’s Republic of China [4]Institute of Advanced Energy,Kyoto University,Kyoto 611-0011,Japan

出　　处：《Plasma Science and Technology》2024年第8期25-31,共7页等离子体科学和技术（英文版）

基　　金：supported by NIFS budgets,KOBF031,ULFF004,KUHR032;partly supported by JSPS KAKENHI 18K04999;JSPS-CAS Bilateral Joint Research Projects,“Control of wall recycling on metallic plasma-facing materials in fusion reactor”2019-2022,(No.GJHZ201984);the Chinese Academy of Sciences President’s International Fellowship Initiative Grant No.2024VMB0003 in FY2023;the U.S.Department Of Energy under Contract No.DE-AC02-09CH11466 with Princeton University。

摘　　要：In the Large Helical Device(LHD),diborane(B2H6)is used as a standard boron source for boronization,which is assisted by helium glow discharges.In 2019,a new Impurity Powder Dropper(IPD)system was installed and is under evaluation as a real-time wall conditioning technique.In the LHD,which is a large-sized heliotron device,an additional helium(He)glow discharge cleaning(GDC)after boronization was operated for a reduction in hydrogen recycling from the coated boron layers.This operational time of 3 h was determined by spectroscopic data during glow discharges.A flat hydrogen profile is obtained on the top surface of the coated boron on the specimen exposed to boronization.The results suggest a reduction in hydrogen at the top surface by He-GDC.Trapped oxygen in coated boron was obtained by boronization,and the coated boron,which has boron-oxide,on the first wall by B-IPD was also shown.Considering the difference in coating areas between B2H6 boronization and B-IPD operation,it would be most effective to use the IPD and B2H6 boronization coating together for optimized wall conditioning.

关 键 词：boron layer oxygen impurity hydrogen recycling impurity powder dropper LHD EAST 

分 类 号：TL63[核科学技术—核技术及应用]