Hayafune, Hiroki; Maeda, Seiichiro; Ohshima, Hiroyuki
Nihon Genshiryoku Gakkai-Shi ATOMO, 61(11), p.798 - 803, 2019/11
In the "Strategic Roadmap" of Fast Reactor Development decided at the Inter-Ministerial Council for Nuclear Power in December 2018, the development works for the around next 10 years were identified, and the role of JAEA was presented. In response, JAEA has prepared a framework for R&D plans for about 5 years on the fast reactor technology and the fuel cycle technology (reprocessing, fuel manufacturing, fuel and material development). In the future, JAEA will promote independent R&D works based on these plans, and provide the obtained R&D results together with various testing functions of JAEA to the activities of the private sector, etc. Through these actions, JAEA will actively contribute to the future fast reactor development. This article outlines JAEA's policy and the R&D items (development of ARKADIA; Advanced Reactor Knowledge- and AI-Aided Design Integration Approach through the whole Plant Life Cycle, development of standards and standards system, development of safety improvement technology, research in the fuel cycle technology), the policy of international cooperation, the human resource development, and the future perspective were explained.
Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Maeda, Hiroki*; Ishiguro, Yuki*; Honda, Takashi*; Jung, J.-S.*; Michimura, Shinji*; Inami, Toshiya; Kimura, Tsuyoshi*; Wakabayashi, Yusuke*
Journal of the Ceramic Society of Japan, 121(3), p.265 - 267, 2013/03
Structural deformation of a magnetocapacitive material SmMnO was studied by X-ray diffraction measurement in a magnetic field. This antiferromagnetic material shows a jump in dielectric constant at 9 K only when a magnetic field of a few tesla is applied. In-field X-ray diffraction measurements clarified that there is no sudden change in structure that involves atomic displacement within the c-plane in Pbnm notation, while the antiferromagnetic phase transition at 60 K gives rise to a noticeable rotation of the MnO octahedra. This rotation occurs to maximize the energy gain through the exchange interaction.
Kitatsuji, Yoshihiro; Okugaki, Tomohiko*; Kasuno, Megumi*; Kubota, Hiroki*; Maeda, Koji*; Kimura, Takaumi; Yoshida, Zenko; Kihara, Sorin*
Journal of Chemical Thermodynamics, 43(6), p.844 - 851, 2011/06
Standard Gibbs energies for transfer (G) of actinyl ions (AnO; z = 2 or 1; An: U, Np or Pu) between an aqueous solution and an organic solution were determined based on distribution method combined with voltammetry for ion transfer at the interface of two immiscible electrolyte solutions. The organic solutions examined were nitrobenzene, 1,2-dichloroethane, benzonitrile, acetophenone and 2-nitrophenyl octyl ether. Irrespective of the type of organic solutions, G of UO, NpO and PuO were nearly equal to each other and slightly larger than that of Mg. The G of NpO was extraordinary large compared with those of ordinary monovalent cations. The dependence of G of AnO on the type of organic solutions was similar to that of H or Mg. The G of An and An were also discussed briefly.
Yada, Hiroki; Tsukimori, Kazuyuki; Maeda, Junichi*
JAEA-Research 2009-045, 64 Pages, 2010/03
In case the electromagnetic pump in the primary sodium purification system of Monju trips up, the sodium flow in the system stops. If we restart the system without stopping the main primary sodium circuit system, the mixing piping structure which connects the branch flow from the purification system to the main flow is subjected to thermal transient load because the cold stagnant sodium is pushed out and the hot sodium from main flow follows. The aim of this study is to assess the fatigue damage of the mixing piping structure in the primary sodium purification system of Monju in case its electromagnetic pump trips up and then it is restarted with keeping plant operation. From the analysis results, we concluded that (1) the fatigue damages were mainly dependent on the temperature difference between the cold sodium at the initial stage and the hot sodium after restart, (2) the fatigue damages were considerably mitigated by preheating and (3) even the severest case allows more than 400 cycles of this events.
Okugaki, Tomohiko*; Kitatsuji, Yoshihiro; Kasuno, Megumi*; Yoshizumi, Asuka*; Kubota, Hiroki*; Shibafuji, Yayoi*; Maeda, Koji*; Yoshida, Zenko; Kihara, Sorin*
Journal of Electroanalytical Chemistry, 629(1-2), p.50 - 56, 2009/04
A high performance electrochemical solvent extraction method was developed based on the quantitative transfer of ions from an aqueous, W, to an organic solution, O. It was realized by applying a potential difference between W and O. The cell was composed of a porous Teflon tube immersed with O, a Ag wire inserted into the tube, a Pt wire placed outside the tube. When W containing ions was forced to flow through the narrow gap between the tube and Ag wire, and potential was applied, a very rapid quantitative ion transfer was attained. When O containing extractant, more than 99% of U(VI) in W was extracted during the residence (e.g., 40 s) in the cell. The fundamental feature of the extraction system was investigated, taking into account the application of the system to the extraction of actinide, lanthanide, Sr or Cs ions. The use of a column electrode system connected before the extraction system was examined in order to adjust the oxidation state of the element to that desired.
Endo, Yuya; Maeda, Tsuyoshi; Uezu, Yasuhiro; Lochard, J.*; Clement, C.*; Fujita, Hiroki*; Ando, Ryoko*
no journal, ,
no abstracts in English
Sato, Kazuyuki; Endo, Yuya; Maeda, Tsuyoshi; Uezu, Yasuhiro; Lochard, J.*; Clement, C.*; Fujita, Hiroki*; Ando, Ryoko*
no journal, ,
no abstracts in English