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Shirasaki, Kenji*; Tabata, Chihiro*; Sunaga, Ayaki*; Sakai, Hironori; Li, D.*; Konaka, Mariko*; Yamamura, Tomoo*
Journal of Nuclear Materials, 563, p.153608_1 - 153608_11, 2022/05
We focused on the direct synthesis of (U, )O
solid solution (
=Th, Np) by extending our recent progress in hydrothermal synthesis with additives. The homogeneity of the (U,
)O
(
= Th, Np) systems prepared by supercritical hydrothermal reactions was investigated through crystallographic analysis based on Vegard's law, and the
Na nuclear magnetic resonance (NMR) measurement of (U, Np, Na)O
solid solutions. Our experimental and analytical results revealed that (i) an optimal additive is ammonium carbonate and starting uranium valence is IV in the case of (U, Th)O
, and (ii) an optimal additive is ethanol and starting uranium valence is VI in the case of (U, Np)O
, for producing the homogeneous solid solutions by hydrothermal synthesis.
Tabata, Chihiro*; Shirasaki, Kenji*; Sunaga, Ayaki*; Sakai, Hironori; Li, D.*; Konaka, Mariko*; Yamamura, Tomoo*
CrystEngComm (Internet), 23(48), p.8660 - 8672, 2021/12
The hydrothermal synthesis of pure uranium dioxide under supercritical water (SCW) conditions was investigated. The nonstoichiometry, crystallite size and morphology of the UO particles were investigated. The SCW hydrothermal synthesis may be a promising method for producing homogeneous UO
and its solid solutions with well-defined nonstoichiometries (
), shapes, and sizes.
Tabata, Chihiro*; Matsumura, Takeshi*; Nakao, Hironori*; Michimura, Shinji*; Kakihana, Masashi*; Inami, Toshiya*; Kaneko, Koji; Hedo, Masato*; Nakama, Takao*; Onuki, Yoshichika*
Journal of the Physical Society of Japan, 88(9), p.093704_1 - 093704_5, 2019/09
Times Cited Count:15 Percentile:86.53(Physics, Multidisciplinary)Tabata, Chihiro*; Inami, Toshiya; Michimura, Shinji*; Yokoyama, Makoto*; Hidaka, Hiroyuki*; Yanagisawa, Tatsuya*; Amitsuka, Hiroshi*
Philosophical Magazine, 94(32-33), p.3691 - 3701, 2014/00
Times Cited Count:14 Percentile:64.03(Materials Science, Multidisciplinary)Tabata, Toshio; Nagao, Yoshiharu; Komukai, Bunsaku; Naka, Michihiro; Takeda, Takashi*; Fujiki, Kazuo
JAERI-Tech 2002-100, 108 Pages, 2003/01
After the investigation of the new core arrangement for the JMTR reactor in order to enhance the fuel burn-up and consequently extend the operation period, the "improved LEU core" that utilized 2 additional fuel elements instead of formerly installed reflector elements, was adopted. This report describes the results of the thermal-hydraulic analysis of the improved LEU core as a part of safety analysis for the licensing. The analysis covers steady state, abnormal operational transients and accidents, which were described in the annexes of the licensing documents as design bases events. Calculation conditions for the computer codes were conservatively determined based on the neutronic analysis results and others. The results of the analysis, that revealed the safety criteria were satisfied on the fuel temperature, DNBR and primary coolant temperature, were used in the licensing. The operation license of the JMTR with the improved LEU core was granted in March 2001, and the reactor operation with new core started in November 2001 as 142nd operation cycle.
Komukai, Bunsaku; Naka, Michihiro; Tabata, Toshio; Nagao, Yoshiharu; Takeda, Takashi*; Fujiki, Kazuo
JAERI-Tech 2002-067, 75 Pages, 2002/08
no abstracts in English
Naka, Michihiro; Nagao, Yoshiharu; Komukai, Bunsaku; Tabata, Toshio
Proceedings of 7th Meeting of the International Group on Research Reactors (IGORR-7) (CD-ROM), 7 Pages, 1999/10
no abstracts in English
Kaneko, Koji; Tabata, Chihiro*; Oishi, Kazuki*; Ito, Takashi; Nakao, Hironori*; Frontzek, M. D.*; Matsuda, Masaaki*; Munakata, Koji*; Nakao, Akiko*; Ohara, Takashi; et al.
no journal, ,
no abstracts in English
Kaneko, Koji; Tabata, Chihiro*; Oishi, Kazuki*; Ito, Takashi; Nakao, Hironori*; Frontzek, M. D.*; Matsuda, Masaaki*; Munakata, Koji*; Nakao, Akiko*; Ohara, Takashi; et al.
no journal, ,
no abstracts in English
Kaneko, Koji; Tabata, Chihiro*; Takeuchi, Tetsuya*; Frontzek, M. D.*; Matsuda, Masaaki*; Oishi, Kazuki*; Ito, Takashi; Munakata, Koji*; Kiyanagi, Ryoji; Kakihana, Masashi*; et al.
no journal, ,