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吉田 純也; 大橋 正樹*; 後藤 良輔*; 長瀬 雄一*; 村井 李奈*; May, S.*; Aye, M. M. T.*; 金原 慎二*; 吉本 雅浩*; 仲澤 和馬*
no journal, ,
J-PARC E07実験は、2016年6月に1st physics run、2017年4月から6月に2nd physics runとしてK-ビームの照射を行い、準備した全ての原子核乾板モジュールに飛跡情報を蓄積した。現在、顕微鏡下でのダブルストレンジネス核を探索する解析作業を継続中である。本講演ではその解析状況について、質、速度、進捗、今後の展望について議論する。
菊池 亮佑*; 藤村 竜也*; 佐藤 努*; 大竹 翼*; 大友 陽子*; 後藤 考裕*; 鈴木 覚*; 谷口 直樹; 鈴木 宏幸*
no journal, ,
In this study, corrosion products in the bentonite in contact with carbon steel coupon under anaerobic artificial seawater at 80 degree for 3 years was investigated using microscopic analysis (SEM, EPMA and FIB-TEM). Corrosion products in compacted bentonite near the interface with carbon steel were identified as Ca-rich siderite, low-crystalline Fe-silicate and montmorillonite with Fe-enriched octahedral sheet. The low-crystalline Fe-silicate was estimated to be a ferrous iron-silicate-hydrate (F-S-H) with an Fe/Si composition of ~1.3 and a structural similarity to a 2:1 type clay with interlayer Na and Ca cations, not the non-swelling 7angstrom phases (greenalite, berthierine and cronstedtite) reported in the literature. The siderite and F-S-H formation were observed over a distance approximately 150 micrometers or less from the interface. The dense formation of siderite and F-S-H at the carbon steel-bentonite interface could suppress the migration of Fe in bentonite and limit the transformation of montmorillonite to 7 angstroms. Unlike previous Fe-clay studies in systems with large reaction surface areas of Fe sources, the experimental system in the present study with a smaller reaction surface area suggests that the decrease in buffer performance is suppressed. Based on thermodynamic calculation, the competition between siderite and F-S-H formation was found to be essentially governed by the pH change near the interface, but an improved database for F-S-H may be needed for more accurate predictions of its formation. The formation of porous F-S-H with large specific surface area in the bentonite interstitial should also be considered in predicting the interaction of electroactive radionuclides such as U and Se, and their migration.