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Ogawa, Shuichi*; Tsuda, Yasutaka; Sakamoto, Tetsuya*; Okigawa, Yuki*; Masuzawa, Tomoaki*; Yoshigoe, Akitaka; Abukawa, Tadashi*; Yamada, Takatoshi*
Applied Surface Science, 605, p.154748_1 - 154748_6, 2022/12
Times Cited Count:4 Percentile:54.33(Chemistry, Physical)Immersion of graphene in KOH solution improves its mobility on SiO/Si wafers. This is thought to be due to electron doping by modification with K atoms, but the K atom concentration C in the graphene has not been clarified yet. In this study, the C was determined by XPS analysis using high-brilliance synchrotron radiation. The time evolution of C was determined by real-time observation, and the C before irradiation of synchrotron radiation was estimated to be 0.94%. The C 1s spectrum shifted to the low binding energy side with the desorption of K atoms. This indicates that the electron doping concentration into graphene is decreasing, and it is experimentally confirmed that K atoms inject electrons into graphene.
Ikeuchi, Hirotomo; Koyama, Shinichi; Osaka, Masahiko; Takano, Masahide; Nakamura, Satoshi; Onozawa, Atsushi; Sasaki, Shinji; Onishi, Takashi; Maeda, Koji; Kirishima, Akira*; et al.
JAEA-Technology 2022-021, 224 Pages, 2022/10
A set of technology, including acid dissolving, has to be established for the analysis of content of elements/nuclides in the fuel debris samples. In this project, a blind test was performed for the purpose of clarifying the current level of analytical accuracy and establishing the alternative methods in case that the insoluble residue remains. Overall composition of the simulated fuel debris (homogenized powder having a specific composition) were quantitatively determined in the four analytical institutions in Japan by using their own dissolving and analytical techniques. The merit and drawback for each technique were then evaluated, based on which a tentative flow of the analyses of fuel debris was constructed.
Kagami, Saya; Yokoyama, Tatsunori; Umeda, Koji*
JAEA-Testing 2021-001, 49 Pages, 2021/08
To make a contribution to safety assessment for geological disposal of high level radioactive and/or TRU waste, we need to assess long-term stability of geological environment and predict long-term changes of geotectonic events that will occur in the future, especially for Quaternary period ( 2.6 million years ago-present). In the most case, we investigate chronological data of geological events by radiometric dating. When some geological samples have no objects to which radiometric dating method can be applied (e.g., zircon, biotite, wood fragments and plant residues), we can use tephrochronology, which is geological dating method using each layer of tephra (erupted volcanic ash), for dating of geological layers. This chronological method is essential in Japan, where volcanism is very active. Tephra is usually characterized by petrographic characteristics and/or chemical composition (mainly major elements) of volcanic glasses and/or minerals in tephra. In Tono Geoscience Center (Japan Atomic Energy Agency), we develop an analytical technique of chemical composition including trace elements of volcanic glasses for detailed tephra identification. In this paper, we report a sample preparation procedure and analytical methods of chemical compositions of individual volcanic glass shards by using an electron probe microanalyzer and a laser ablation-inductively coupled plasma-mass spectrometer.
Terashima, Motoki; Endo, Takashi*; Miyakawa, Kazuya
Journal of Nuclear Science and Technology, 57(4), p.380 - 387, 2020/04
Times Cited Count:2 Percentile:20.94(Nuclear Science & Technology)Kusaka, Ryoji
Bunko Kenkyu, 67(6), p.239 - 240, 2018/12
A spectroscopic technique for analysis developed by collaboration between Japan Atomic Energy Agency (JAEA) and Quantum and Radiological Science and Technology (QST) is discussed for readers outside the field of nuclear energy. This paper introduces a quantitative analysis for Pd radioisotope contained in a spent nuclear fuel by using laser-induced photoreduction and inductively coupled plasma mass spectrometry (ICP-MS). The importance and problems of quantitative analysis for radioisotopes in spent nuclear fuels are described, and the principle, advantages, and future applications of the spectroscopic technique are discussed.
; Mihara, Morihiro;
JNC TN8430 2001-007, 56 Pages, 2002/01
In the geological disposal concept of radioactive wastes, a kind of clay with sorption ability and low permeability, called bentonite, is envisaged as an engineered barrier system in the geological repository. Also, the cemetitious material is envisaged as the backfill material in the vaults and the structure material of the vaults. The groundwater in contact with the cementitious material will promote hyperalkaline conditions in the repository environment and these conditions will affect the performance of the bentonite. Therefore, it is necessary to investigate the interaction between the cementitious material and the bentonite for the evaluation of long term stability of the disposal system. In this study, for the identification and the investigation of the secondary minerals, the batch immersion experiments of the powder bentonite were carried out using synthetic cement leachates (pH=7, 12.5, 14) at 200C. As the results, it was confirmed that Na as exchangeable cations in the bentonite can exchange relatively easily with Ca in the solution from the experiment results. And the ratio of cation exchange was estimated to be about 25% based on the amount of exchangeable cations Ca between layers. Furthermore, it was concretely shown that the generation of analcime might be affected by the Na concentration from results of the solution analyses and a stability analysis of analcime using the chemical equilibrium model, in addition to the pH in the solution.
Sakai, Takuro; Kamiya, Tomihiro; Oikawa, Masakazu*; Sato, Takahiro; Tanaka, Akira*; Ishii, Keizo*
Nuclear Instruments and Methods in Physics Research B, 190(1-4), p.271 - 275, 2001/09
Times Cited Count:66 Percentile:95.95(Instruments & Instrumentation)no abstracts in English
Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Watanabe, Kazuo; Usuda, Shigekazu; Nishimura, Hideo; Adachi, Takeo
Applied Radiation and Isotopes, 53(1-2), p.87 - 90, 2000/07
Times Cited Count:28 Percentile:84.24(Chemistry, Inorganic & Nuclear)no abstracts in English
Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Tsuruta, Yasuhiro; Tsuda, Shinji; Watanabe, Kazuo; Usuda, Shigekazu; Nishimura, Hideo; et al.
Kaku Busshitsu Kanri Gakkai Nihon Shibu Dai-20-Kai Kinen Taikai Rombunshu, p.183 - 187, 1999/11
no abstracts in English
Kato, Toshihiro*; ; ; ; Ishibashi, Yuzo; Takeda, Seiichiro
PNC TN8410 98-070, 31 Pages, 1998/02
None
Magara, Masaaki; Yonezawa, Chushiro
Nuclear Instruments and Methods in Physics Research A, 411(1), p.130 - 136, 1998/00
Times Cited Count:24 Percentile:85.09(Instruments & Instrumentation)no abstracts in English
Hegazy, EI-Sayed A.*; Sasuga, Tsuneo; Nishii, Masanobu; Seguchi, Tadao
Polymer, 33(14), p.2904 - 2910, 1992/00
Times Cited Count:28 Percentile:74.77(Polymer Science)no abstracts in English