R&D of invar duct for fabrication of 2nd JSNS moderators
原田 正英; 勅使河原 誠; 前川 藤夫; 大井 元貴; 春日井 好己; 高田 弘
Harada, Masahide; Teshigawara, Makoto; Maekawa, Fujio; Oi, Motoki; Kasugai, Yoshimi; Takada, Hiroshi
Japan Spallation Neutron Source (JSNS) in Japan Proton Accelerator Research Complex (J-PARC) has three super-critical hydrogen moderators. The moderator piping has a multilayer structure; a cryogenic layer, a vacuum layer, a helium layer and a cooling water layer. Through the fabrication of the current (1st) moderators, we learned that thermal shrinkage between room temperature (R.T.) and cryogenic temperature at the cryogenic layer made the fabrication process very difficult. Therefore, for the spare (2nd) moderators, we proposed to use a low thermal shrinkage material, Invar, as a piping material. However, there were items to be solved for realizing the Invar duct inview of the fabrication. In this presentation, we report results of (1) Bending test, (2) Welding test and (3) Dissimilar joint test on the Invar duct. (1) In the bending test, the Invar ducts of 22 mm in diameter and 1.5 mm in thickness were tried to be bent into an elbow with 40 mm in radius. By pre-cooling the duct in the liquid nitrogen followed by the bending with slow speed (1 minute), the duct could be bent without any cracks. (2) Through some welding testes by TIG-welding, the proper groove geometry was determined. (3) For the dissimilar joint test, tensile specimens including a bonding region having size of 4 or 6 mm in diameter at the smallest part and 60 mm in length were cut from three rods made by Invar-A6061 and Invar-SS316L, respectively. Those rods were bonded by the friction welding. All specimens were examined at two temperatures, R.T. and 77 K (liquid nitrogen temperature), resulting that 0.2% proof stresses corresponding to the bonding strengths were larger than those of base materials for both the Invar-A6061 and the Invar-SS316L cases. The present result indicates that the Invar duct is available for the 2nd moderators.
使用言語 : English
掲載資料名 : Journal of Nuclear Materials
: 450
: 1-3
ページ数 : p.104 - 109
発行年月 : 2014/07
出版社名 : Elsevier
発表会議名 : 11th International Workshop on Spallation Materials Technology (IWSMT-11)
開催年月 : 2012/11
開催都市 : Ghent
開催国 : Belgium
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登録番号 : BB20122486
抄録集掲載番号 : 42000871
論文投稿番号 : 14528
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