Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Fuyushima, Takumi; Takabe, Yugo; Sayato, Natsuki; Kimura, Akihiro; Takemoto, Noriyuki
The IV International Scientific Forum "Nuclear Science and Technologies"; AIP Conference Proceedings 3020, p.040007_1 - 040007_6, 2024/01
We studied irradiation tests of structural materials simulating fast reactor conditions in JMTR. We fabricated capsules that can simulate fast reactor irradiation in JMTR by using He/dpa ratio as index. To simulate fast reactor, cadmium, which shield thermal neutrons, was placed inside the capsule to adjust the neutron spectrum. According to the result of irradiation tests by neutron spectrum adjusting capsule, we confirmed that it can simulate the He/dpa ratio of fast reactor. Currently, since it is impossible to conduct irradiation tests in Japan, a plan is underway to partly replace the irradiation function of JMTR with overseas reactors. The alternative irradiation will be carried out by succeeding and developing the irradiation technology accumulated in the JMTR, and as a part of this, a trial of such irradiation in which the neutron spectrum is adjusted is under consideration.
Yuguchi, Takashi*; Ito, Daichi*; Yokoyama, Tatsunori; Sakata, Shuhei*; Suzuki, Satoshi*; Ogita, Yasuhiro; Yagi, Koshi*; Imura, Takumi*; Motai, Satoko*; Ono, Takeshi*
Lithos, 440-441, p.107026_1 - 107026_14, 2023/03
Times Cited Count:0 Percentile:0.02(Geochemistry & Geophysics)We propose a new method for elucidating zircon growth in granitic plutons, based on variations in three-dimensional 3D cathodoluminescence (CL) patterns, U-Pb ages, titanium concentration, and Th/U ratios. We focused on the zircon growth processes in the Okueyama granite (OKG) in central Kyushu, Japan, to obtain interpretations of magma chamber processes that result in the formation of granitic plutons. The OKG consists of three lithofacies: biotite granite (BG), hornblende granite (HG), and hornblende granodiorite (HGD). To determine the 3D internal structure and growth pattern of a zircon crystal, we performed CL observations for multi-sections of the samples. Simultaneously, we also determined the zircon U-Pb age and titanium concentration of the center sections of the samples. The 3D distribution of the oscillatory zoning can be used to determine the crystal nucleus. The simultaneous determination of zircon U-Pb ages and Ti concentrations of the granite samples indicates the time-temperature (t-T) history of granitic magma before its solidification. The t-T histories of the BG, HG, and HGD represented similar cooling behaviors within the magma chamber: rapid cooling from the zircon crystallization temperature to the closure temperature of the biotite K-Ar system between 16 Ma and 10 Ma. The variations in the Th/U ratios against temperature also demonstrate a different trend at the boundary of approximately 670 C. Fractional crystallization in the magma chamber progressed significantly at temperatures above 670 C; below 670 C, crystallization progressed slowly, indicating only minimal changes in the magma composition. The variations in the Th/U ratio against temperature in the BG, HG, and HGD portrayed common tendencies, indicating the same behavior in the progression of fractional crystallization among the three lithofacies, which in turn, represented the same behavior within the entire magma chamber.
Yuguchi, Takashi*; Yamazaki, Hayato*; Ishibashi, Kozue*; Sakata, Shuhei*; Yokoyama, Tatsunori; Suzuki, Satoshi*; Ogita, Yasuhiro; Sando, Kazusa*; Imura, Takumi*; Ono, Takeshi*
Journal of Asian Earth Sciences, 226, p.105075_1 - 105075_9, 2022/04
Times Cited Count:4 Percentile:57.69(Geosciences, Multidisciplinary)Simultaneous determination of the U-Pb age of zircon and concentration of titanium in a single analysis spot, using inductively coupled plasma mass spectrometry with laser ablation sample introduction, produces paired age and temperature data of zircon crystallisation, potentially revealing time-temperature () histories for evolved magma. The Kurobegawa granite, central Japan, contains abundant mafic magmatic enclaves (MMEs). We applied this method to evaluate MMEs and their host (enclosing) granites. Cooling behaviour common to both MMEs and host rocks was found between 1.5 and 0.5 Ma. Rapid cooling from the zircon crystallisation temperature to the closure temperature of biotite K-Ar system was within 1 million year. Combining the obtained paths of MMEs and host rocks with petrological information can provide insights into magma chamber processes. This suggests that MME flotation, migration, and spread through the magma chamber ceased at 1.5-0.5 Ma, indicating the emplacement age of the Kurobegawa granitic pluton, as no large-scale reheating episodes have occurred since then.
Tsujimura, Norio; Yamazaki, Takumi; Takada, Chie
Journal of Nuclear Science and Technology, 58(1), p.40 - 44, 2021/01
Times Cited Count:3 Percentile:34.82(Nuclear Science & Technology)Tsujimura, Norio; Hoshi, Katsuya; Yamazaki, Takumi; Momose, Takumaro; Aoki, Katsunori; Yoshitomi, Hiroshi; Tanimura, Yoshihiko; Yokoyama, Sumi*
KEK Proceedings 2020-5, p.21 - 28, 2020/11
Okudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.
EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12
Parity violating effects enhanced by up to 10 times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,) reaction was measured with La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized La target and a 70% polarized He spin filter whose thickness is 70 atmcm are needed. Therefore high quality He spin filter is developed in JAEA. The measurement result of the (n,) reaction at J-PARC and the development status of the He spin filter will be presented.
Strasser, P.*; Abe, Mitsushi*; Aoki, Masaharu*; Choi, S.*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Katsuhiko*; et al.
EPJ Web of Conferences, 198, p.00003_1 - 00003_8, 2019/01
Times Cited Count:13 Percentile:98.93(Quantum Science & Technology)Yamazaki, Takumi; Takada, Chie; Tsujimura, Norio; Okada, Kazuhiko
Hoken Butsuri, 52(3), p.167 - 170, 2017/09
At the JAEA MOX Fuel Facilities, a worker engaged in glove box operations uses two personal dosemeters, one worn on the trunk under a protective apron and the other at the collar over the apron. The recorded lens of the eye dose is based on the photon dose measured by the collar dosemeter plus the neutron dose measured by the under-apron dosemeter.
Sasaki, Takayuki*; Ueda, Kenyo*; Saito, Takumi; Aoyagi, Noboru; Kobayashi, Taishi*; Takagi, Ikuji*; Kimura, Takaumi; Tachi, Yukio
Journal of Nuclear Science and Technology, 53(4), p.592 - 601, 2016/04
Times Cited Count:12 Percentile:74.37(Nuclear Science & Technology)The influences of pH and the concentrations of Eu and NaNO on the sorption of Eu to Na-montmorillonite were investigated through batch sorption measurements and time-resolved laser fluorescence spectroscopy (TRLFS). The pH had a little effect on the distribution coefficients (Kd) in 0.01 M NaNO, whereas the Kd strongly depended on pH at 1 M NaNO. A cation exchange model combined with a one-site non-electrostatic surface complexation model was successfully applied to the measured Kd. The TRLFS spectra of Eu sorbed were processed by parallel factor analysis (PARAFAC), which corresponded to one outer-sphere (factor A) and two inner-sphere (factor B and C) complexes. It turned out that factors A and B correspond to Eu sorbed by ion exchange sites and inner-sphere complexation with hydroxyl groups of the edge faces, respectively. Factor C became dominant at relatively high pH and ionic strength and likely correspond to the precipitation of Eu(OH) on the surface.
Nakajima, Kaoru*; Kitayama, Takumi*; Hayashi, Hiroaki*; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Toulemonde, M.*; Bouffard, S.*; Kimura, Kenji*
Scientific Reports (Internet), 5, p.13363_1 - 13363_8, 2015/08
Times Cited Count:5 Percentile:40.93(Multidisciplinary Sciences)Kitayama, Takumi*; Nakajima, Kaoru*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Isoda, Shoji*; Kimura, Kenji*
Nuclear Instruments and Methods in Physics Research B, 354, p.183 - 186, 2015/07
Times Cited Count:2 Percentile:17.52(Instruments & Instrumentation)Saito, Takumi; Aoyagi, Noboru; Kimura, Takaumi
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1129 - 1132, 2015/02
Times Cited Count:14 Percentile:75.23(Chemistry, Analytical)Time-resolved laser-induced fluorescence spectroscopy (TRLFS) is a powerful speciation technique for fluorescent metal ions and can be further improved by combining with multi-mode factor analysis such as parallel factor analysis (PARAFAC). This study demonstrates the applicability of TRLFS combined with PARAFAC for the speciation of uranyl (UO) in the presence of silicic acid (Si(OH)). A series of TRLFS data with varied Si(OH) concentration was processed by PARAFAC, resulting in three factors corresponding to free UO, UOSiO(OH), and UOOH. The stability constant of UOSiO(OH) was further optimized, based on the intensity profiles of the factors.
Nakajima, Kaoru*; Morita, Yosuke*; Kitayama, Takumi*; Suzuki, Motofumi*; Narumi, Kazumasa; Saito, Yuichi; Tsujimoto, Masahiko*; Isoda, Shoji*; Fujii, Yoshikazu*; Kimura, Kenji*
Nuclear Instruments and Methods in Physics Research B, 332, p.117 - 121, 2014/08
Times Cited Count:7 Percentile:48.18(Instruments & Instrumentation)Mao, W.*; Chikada, Takumi*; Shimura, Kenichiro*; Suzuki, Akihiro*; Yamaguchi, Kenji; Terai, Takayuki*
Journal of Nuclear Materials, 443(1-3), p.555 - 561, 2013/11
Times Cited Count:3 Percentile:25.59(Materials Science, Multidisciplinary)In this work, calculations based on density functional theory (DFT) and generalized gradient approximation were performed to investigate the structural and electronic properties of the cubic ErO (001) surface and H adsorption processes on this surface. Several stable adsorption sites were identified, and at the most energetically favorable adsorption sites it was found that H bonds with O atoms at the cubic ErO (001) surface with an adsorption energy of 295.68 kJ mol at coverage 1/8 ML, which was inclined to decrease with the increase of H coverage ( 1/4 ML). In addition, the calculations revealed that the dissociative H atom configurations have adsorption energies that are at least 152.64 kJ mol greater than the H molecule configurations on the surface. These results are discussed in regard of the hydrogen isotope permeation behavior in the tritium permeation barrier in a fusion reactor.
Aoyagi, Noboru; Saito, Takumi*; Kimura, Takaumi
Bunseki, 2013(9), p.536 - 542, 2013/09
no abstracts in English
Okamura, Hiroyuki; Ikeda, Atsushi*; Saito, Takumi*; Aoyagi, Noboru; Naganawa, Hirochika; Hirayama, Naoki*; Umetani, Shigeo*; Imura, Hisanori*; Shimojo, Kojiro
Analytical Chemistry, 84(21), p.9332 - 9339, 2012/11
Times Cited Count:23 Percentile:62.28(Chemistry, Analytical)Lukman, S.*; Saito, Takumi*; Aoyagi, Noboru; Kimura, Takaumi; Nagasaki, Shinya*
Geochimica et Cosmochimica Acta, 88, p.199 - 215, 2012/07
Times Cited Count:24 Percentile:56.4(Geochemistry & Geophysics)Ishida, Keisuke*; Saito, Takumi*; Aoyagi, Noboru; Kimura, Takaumi; Nagaishi, Ryuji; Nagasaki, Shinya*; Tanaka, Satoru*
Journal of Colloid and Interface Science, 374(1), p.258 - 266, 2012/05
Times Cited Count:29 Percentile:57.94(Chemistry, Physical)Okamura, Hiroyuki; Sakae, Hiroki*; Kidani, Keiji*; Hirayama, Naoki*; Aoyagi, Noboru; Saito, Takumi*; Shimojo, Kojiro; Naganawa, Hirochika; Imura, Hisanori*
Polyhedron, 31(1), p.748 - 753, 2012/01
Times Cited Count:29 Percentile:87.57(Chemistry, Inorganic & Nuclear)Collins, R. N.*; Saito, Takumi*; Aoyagi, Noboru; Payne, T. E.*; Kimura, Takaumi; Waite, T. D.*
Journal of Environmental Quality, 40(3), p.731 - 741, 2011/05
Times Cited Count:33 Percentile:63.56(Environmental Sciences)