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Takahashi, Yutaka*; Mikoshiba, Masumi*; Shimura, Toshiaki*; Nagata, Mitsuhiro; Iwano, Hideki*; Danhara, Toru*; Hirata, Takafumi*
Island Arc, 30(1), p.e12393_1 - e12393_15, 2021/01
Times Cited Count:2 Percentile:16.39(Geosciences, Multidisciplinary)The Hidaka metamorphic belt is an excellent example of island-arc-type crust, and in this belt the metamorphic grade increases westwards from unmetamorphosed sediment up to the granulite facies. The metamorphic age of the belt had previously been considered to be ca. 55 Ma. However, zircons from the granulites in the lower sequence have given U-Pb ages of ca. 21-19 Ma and a preliminary report on zircons from pelitic gneiss in the upper sequence gave a U-Pb age of ca. 40 Ma. In this paper we provide new U-Pb ages for zircons from the pelitic gneisses in the upper sequence in order to assess the metamorphic age and also the maximum depositional age of the sedimentary protolith. The weighted mean Pb/U ages and 2 sigma errors for zircons from biotite gneiss in the central area of the belt are 39.6 0.9 Ma for metamorphic overgrowth rims and 53.1 0.9 Ma for the youngest inherited detrital cores. The ages of zircons from cordierite-biotite gneiss in the southern area are 35.9 0.7 Ma for overgrowth rims and 46.5 2.8 Ma for the youngest detrital cores. These results indicate that the metamorphism of the upper sequence took place at ca. 40-36 Ma, and that the sedimentary protolith was deposited after ca. 53-47 Ma. These metamorphic ages are consistent with the reported ages of ca. 37-36 Ma plutonic rocks in the upper sequence, but contrast with the ca. 21-19 Ma ages of metamorphic and plutonic rocks in the lower sequence. Therefore, we conclude, that the upper and lower metamorphic sequences developed independently but became coupled before ca. 19 Ma as a result of dextral reverse tectonic movements, as indicated by the intrusion of ca. 19-18 Ma magmas, possibly generated in the lower sequence, into the upper sequence.
Shimizu, Takeshi*; Wang, H.*; Tanifuji, Naoki*; Matsumura, Daiju; Yoshimura, Masashi*; Nakanishi, Koji*; Ota, Toshiaki*; Yoshikawa, Hirofumi*
Chemistry Letters, 47(5), p.678 - 681, 2018/05
Times Cited Count:9 Percentile:33.47(Chemistry, Multidisciplinary)Maeda, Yukimoto; Kashimura, Yoichi; Suzuki, Toshiaki; Isozaki, Kazunori; Hoshiba, Hideaki; Kitamura, Ryoichi; Nakano, Tomoyuki; Takamatsu, Misao; Sekine, Takashi
JNC TN9440 2005-001, 540 Pages, 2005/02
Periodic safety review (Review of the activity for safety) which consisted of "Comprehensive evaluation of operation experience" and "Incorporation of the latest technical knowledge" was carried out up to January 2005.
Maekawa, Kazuhiko*; Yoshimura, Tadahiro*; Kikuchi, Toshiaki*; Hoshino, Yasushi*; Munekata, Hideki*; Shimizu, Makoto*
JNC TJ9420 2005-004, 284 Pages, 2005/02
In feasibility studies on commercialized FBR cycle system, comprehensive system investigation and properties evaluation for candidate FBR cycle systems have been implemented through view point of safety, economics, environmental burden reduction, non-proliferation resistivity, etc. As part of these studies, an investigation of small scale sphere-pac fuel fabrication plant with external gelation process was conducted. Until last fiscal year, equipment layout in cells and overall layout design of the 200t-HM/y scale fuel fabrication plant were conducted as well as schematical design studies on main equipments in gelation and reagent recovery processes of the plant. System property data concerning economics and environmental burden reduction of fuel fabrication plant was also acquired. In this fiscal year, the processes from vibropacking to fuel assemblies storage were added to the investigation range, and a conceptual design of whole fuel fabrication plant was studied as well as deepening the design study on main equipments. The conceptual design study was mainly conducted for small 50t-HM/y scale plant and a revising investigation was done for 200t-HM/y scale Plant. Taking the planed comparative evaluation with pellet fuel fabrication system into account, design of equipments which should be equivalent with pellet system, especially in post-vibropacking processes, were standardized in each system. Based on these design studies, system properties data concerning economics and environmental burden reduction of the plant was also acquired. In comparison with existing design, the cell height was lowered on condition that plug type pneumatic system was adopted and fuel fabrication building was downsized by applying rationalized layout design of pellet system to post-vibropacking processes. Reduction of reagent usage at gelation process and rationalization of sintering and O/M controlling processes etc., are foremost tasks.
Endo, Kiyoshi*; Matsumura, Akira*; Yamamoto, Tetsuya*; Nose, Tadao*; Yamamoto, Kazuyoshi; Kumada, Hiroaki; Kishi, Toshiaki; Torii, Yoshiya; Kashimura, Takanori*; Otake, Shinichi*
Research and Development in Neutron Capture Therapy, p.425 - 430, 2002/09
Using the Rapid Prototyping Technique, we produced a realistic phantom as a formative model of a patient head. This realistic phantom will contribute to verification of our planning system. However, cross-correlation among the calculations using the JAERI Computational Dosimetry System (JCDS), the realistic phantom, and the in vivo measurements were not fully completed because of the difficulty involved in modeling a post-surgical brain and a thermal neutron shield. The experimental simulation technique using the realistic phantom is a useful tool for more reliable dose planning for the intraoperative BNCT.
Higuchi, Hidetoshi; Koizumi, Kenji; Washiya, Tadahiro; Morita, Shinichi; Chikazawa, Takahiro*; Nishimura, Kenji*; Kikuchi, Toshiaki*
no journal, ,
Influence of UNH crystal on heat transfer performance of Crystallizer.
Noda, Kyoko*; Takao, Koichiro*; Sugiyama, Yuichi*; Harada, Masayuki*; Nogami, Masanobu*; Maruyama, Koichi*; Takahashi, Hiroaki*; Kim, S.-Y.; Sato, Makoto; Mineo, Hideaki; et al.
no journal, ,
We have been developing an advanced reprocessing system for spent FBR fuels based on precipitation method using pyrrolidone derivatives. In previous investigation, N-cyclohexyl-2-pyrrolidone (NCP) is used as a precipitant, which is able to precipitate selectively UO ions in HNO solution, and a process consisting of two separation steps; selective U precipitation step and U-Pu co-precipitation step, was developed. In order to make the process more effective and more economical, we are now studying precipitation of U and Pu with other pyrrolidone derivatives. The outline of the study and main results obtained until now are shown in this presentation.
Shibahara, Takahiro*; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; Nishimura, Kenji*; Morita, Yasuji; Ikeda, Yasuhisa*
no journal, ,
Thermal decomposition of precipitants of U(VI) with pyrrolidone derivatives was investigated for the development of an advanced reprocessing system for spent FBR fuels based only on precipitation method using the pyrrolidone derivatives. We have examined N-cyclohexyl-2-pyrrolidone (NCP), N-n-butyl-2-pyrrolidone (NBP) and N-propyl-2-pyrrolidone (NProP) as the precipitants. It was found that U(VI) precipitates with those precipitants were decomposed at higher than 450 C and such thermal treatment produced U oxides with low impurities.
Nishimura, Akihiko; Asai, Toshiki; Hoshiya, Taiji; Kimura, Toyoaki; Uchikoshi, Katsumi; Matsuda, Toshiaki
no journal, ,
Science seminar activities by JAEA-Kansai have been progressed since 2002 up to now for high school students. The outline of the activities has been summarized.
Nogami, Masanobu*; Kawasaki, Takeshi*; Takao, Koichiro*; Noda, Kyoko*; Sugiyama, Yuichi*; Harada, Masayuki*; Ikeda, Yasuhisa*; Morita, Yasuji; Chikazawa, Takahiro*; Kikuchi, Toshiaki*; et al.
no journal, ,
A reprocessing system for spent FBR fuels based on the two precipitation processes has been proposed. In this system, first only U(VI) species are precipitated using pyrrolidone derivatives (NRP) with low hydrophobicity and donicity, and secondly residual U(VI) and Pu(IV, VI) are precipitated simultaneously using pyrrolidone derivative with high precipitation ability. In order to develop such a reprocessing method, behavior of uranyl ions in HNO has been studied using various novel NRP. In this presentation, recent advances on precipitation behavior and of uranyl ions and calcination of U(VI)-NRP will be introduced.
Kim, S.-Y.; Kawata, Yoshihisa; Morita, Yasuji; Nogami, Masanobu*; Harada, Masayuki*; Ikeda, Yasuhisa*; Kikuchi, Toshiaki*; Nishimura, Kenji*
no journal, ,
A reprocessing system for spent FBR fuels based on the two precipitation processes has been proposed. In this system, first only U(VI) species are precipitated using pyrrolidone derivatives (NRP) with low hydrophobicity and donicity, and secondly residual U(VI) and Pu(IV, VI) are precipitated simultaneously using pyrrolidone derivative with high precipitation ability. It is important to control precipitation of Pu(IV), and recent advances on precipitation behavior of Pu(IV, VI) by using novel pyrrolidone derivatives will be introduced in this presentation. Precipitation tests using mixed solutions of U(VI) and Pu(IV) showed that N-n-butyl-2-pyrrolidone (NBP) is the most appropriate precipitant for the first precipitation step and N-neopenthyl-2-pyrrolidone (NNpP) is the most appropriate precipitant for the second step.
Motohashi, Jun; Yagi, Masahiro; Kishi, Toshiaki; Kashimura, Takanori
no journal, ,
no abstracts in English
Takayama, Reona*; Oe, Kazuhiro*; Komori, Yukiko*; Fujisawa, Hiroyuki*; Kuriyama, Ai*; Kikutani, Yuki*; Kikunaga, Hidetoshi*; Kasamatsu, Yoshitaka*; Yoshimura, Takashi*; Takahashi, Naruto*; et al.
no journal, ,
The extraction behavior of trivalent actinides (Am, Cm, Cf, Es, and Fm) into di(2-ethylhexyl)phosphoric acid, HDEHP, in benzene from HNO was studied together with lanthanides. The extraction constants, values, of lanthanides, Am, Cm, Cf, and Es were determined by a batch method using stable lanthanide isotopes and radiotracers of Am, Cm, Cf, and Es, respectively, while that of Fm was measured with Fm which was produced in the U(O,4n) reaction and was on-line supplied by a gas-jet method at the AVF cyclotron of RCNP, Osaka University. The values were determined by the slope analysis for the variation of the distribution ratio as a function of the concentration of HDEHP. We found that the of Fm is smaller than that of Dy in spite of the similar ionic radii while those of other actinides are almost the same as those of each lanthanide with a similar ionic radius.
Saisu, Motofumi*; Uchiyama, Keizo*; Ishii, Toshiaki*; Ando, Tadahiko*; Ueno, Toshihiro*; Nakayama, Kazumi*; Sato, Rina; Yoshimura, Kazuya; Sanada, Yukihisa
no journal, ,
no abstracts in English