Concepts and basic designs of various nuclear fuels, 5; Fuels for high temperature gas-cooled reactor and molten salt reactor

Ueta, Shohei; Sasaki, Koei; Arita, Yuji*

Nihon Genshiryoku Gakkai-Shi ATOMO, 63(8), p.615 - 620, 2021/08

https://doi.org/10.3327/jaesjb.63.8_615

no abstracts in English

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03

http://www.jspf.or.jp/Journal/PDF_JSPF/jspf2016_03/jspf2016_03-157.pdf

The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.

Application of Laser-Induced Breakdown Spectroscopy (LIBS) analysis to molten alloy production process

Ozu, Akira; Tachi, Yoshiaki; Arita, Yuji*

Reza Kenkyu, 42(12), p.913 - 917, 2014/12

Laser-induced breakdown spectroscopy (LIBS) analysis has been applied to the molten alloy production process, in which simulated metals (Zr, Cu, Sm, Ce) are used instead of nuclear metallic fuels contained minor actinide (MA), with the aim of in-situ monitoring the elementary composition of the surface of the molten alloy in a chamber and vapor particles generated from the surface of the molten alloy. The variation in the ratio of elementary composition of the surface of the molten alloy in the crucible was successfully observed depending on temperature of the crucible. The elementary composition of the vapor particles appeared in the molten alloy chamber was also measured. The practical experimental results show that LIBS technique is very useful for investigating the elementary composition in the process and understanding the behavior of molten alloy in the crucible.

Research on decommissioning of nuclear facilities, 2; Study on optimum scenario using the AHP (Joint research)

Shibahara, Yuji; Ishigami, Tsutomu; Morishita, Yoshitsugu; Yanagihara, Satoshi*; Arita, Yuji*

JAEA-Technology 2012-038, 72 Pages, 2013/01

JAEA-Technology-2012-038.pdf:3.68MB

To implement a decommissioning project reasonably, it is necessary and important to beforehand evaluate project management data as well as to select an optimum dismantling scenario among various scenarios postulated. Little study on the subject of selecting an optimum scenario has been carried out, and it is one of the most important subjects in terms of decision making. In FY 2009, Japan Atomic Energy Agency and University of Fukui launched the joint research of a decision making method which is important to determine a decommissioning plan. The purpose of this research is to construct a methodology for selecting an optimum dismantling scenario among various scenarios postulated based on calculated results of project management data for FUGEN. Project management data for several dismantling scenarios postulated at FUGEN were evaluated based on actual dismantling work for feedwater heater at FUGEN, and an optimum scenario was discussed using the AHP, one of Multi-Criteria Decision Analysis Method. This report describes the results of the joint research in FY 2010.

Immobilization of alkyl chain molecules on oxide surface using phosphonic acid as an anchor

Narita, Ayumi; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Yaita, Tsuyoshi

e-Journal of Surface Science and Nanotechnology (Internet), 10, p.367 - 373, 2012/07

https://doi.org/10.1380/ejssnt.2012.367

To apply organic thin films as new devices, it is important to immobilize organic molecules on oxide surfaces. In this study, we investigated the formation of organic self-assembled monolayer on the oxide surface. Decyl phosphonic acid (DPA) molecules were used as the adsorbed molecule on the surface. The DPA film was prepared by immersing the sapphire substrate in DPA ethanol solution. The sample was measured by XPS using synchrotron soft X-ray. For the P 1s XPS spectra of the DPA powder and the DPA film on the sapphire surface, a single peak was observed and the binding energies of the two samples were almost the same. And we measured the sample by the total reflection (TR) XPS, which is highly surface sensitive method. Compared with the normal XPS, the intensity of the C 1s peak in TR-XPS was enhanced. As a result, it was elucidated that the phosphonic acid of the DPA molecule was located at the lower side, while the alkyl chain was located at the upper side on the surface.

Structure determination of self-assembled monolayer on oxide surface by soft-X-ray standing wave

Baba, Yuji; Narita, Ayumi; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Entani, Shiro; Sakai, Seiji

e-Journal of Surface Science and Nanotechnology (Internet), 10, p.69 - 73, 2012/04

https://doi.org/10.1380/ejssnt.2012.69

We report on the first results for the geometrical determination of adsorbed atoms on an oxide by a soft-X-ray sanding wave method. The samples investigated were alkyl phosphonic acid (C10) adsorbed on a sapphire surface, which is one of the candidate systems for organic self-assembled monolayer (SAM) on oxides. The surface was irradiated by synchrotron soft X-rays from the surface normal. The intensity of photoelectrons was plotted as a function of the photon energy. We observed clear profiles of the photoelectron intensity due to the standing wave from the substrate. Compared with the simulation using the crystal parameters, it was found that the phosphorus atoms are located at 0.11 nm from the surface, while the constant height was not observed for carbon atoms. The results are in consistent with the results by XPS and NEXAFS; the molecules form SAM on the sapphire surface with phosphonic acids and alkyl chains are located at the upper side.

Structure determination of self-assembled monolayer on oxide surface by soft-X-ray standing wave

Baba, Yuji; Narita, Ayumi; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Entani, Shiro; Sakai, Seiji

Photon Factory Activity Report 2011, Part B, P. 201, 2012/00

http://pfwww.kek.jp/acr2011pdf/part_b/pf11b201.pdf

no abstracts in English

J-ACTINET activities of training and education for actinide science research

Minato, Kazuo; Konashi, Kenji*; Yamana, Hajimu*; Yamanaka, Shinsuke*; Nagasaki, Shinya*; Ikeda, Yasuhisa*; Sato, Seichi*; Arita, Yuji*; Idemitsu, Kazuya*; Koyama, Tadafumi*

Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12

Actinide science research is indispensable to maintain sustainable development of innovative nuclear technology. For actinide science research, special facilities with containment and radiation shields are needed to handle actinide materials. The number of facilities for actinide science research has been decreased, especially in universities, due to the high maintenance cost. J-ACTINET was established in 2008 to promote and facilitate actinide science research and to foster many of young scientists and engineers in actinide science. The research program was carried out, through which young researchers were expected to learn how to make experiments with advanced experimental tools and to broaden their horizons. The summer schools and computational science school were held to provide students and young researchers with the opportunities to come into contact with actinide science research. The overseas dispatch program was also carried out.

Self-ordering of silicon polymer thin film grown on indium tin oxide surface investigated by X-ray absorption spectroscopy

Mannan, M. A.*; Baba, Yuji; Sekiguchi, Tetsuhiro; Shimoyama, Iwao; Hirao, Norie; Narita, Ayumi; Nagano, Masamitsu*; Noguchi, Hideyuki*

Journal of Electron Spectroscopy and Related Phenomena, 181(2-3), p.242 - 248, 2010/08

https://doi.org/10.1016/j.elspec.2010.02.014

The ordering and molecular orientation of polydimethylsilane (PDMS) films grown on indium tin oxide (ITO) surface has been assigned. The orientation of the samples as well as that of the annealed sample was studied by Si K-edge near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy using linearly polarized synchrotron radiation. The Si K-edge NEXAFS spectra for the thick film have at least four resonance peaks of which two peaks are found to be strongly polarization dependent. On the basis of the polarization dependences of the peak intensities, it is revealed that the backbones of the PDMS films are perpendicularly oriented on the ITO surface. The angle between surface and the Si-Si bonds for multilayered film calculated from the helical structure of PDMS molecule was found to be 41.5 which was almost coincided with the experimentally obtained angle of 40 . It was concluded that PDMS molecules are highly self-ordered on ITO surface.

Preparation of TRU alloys by electrochemical or lithium reduction method

Nakajima, Kunihisa; Iwai, Takashi; Arai, Yasuo; Kurata, Masaki*; Nakamura, Kinya*; Arita, Yuji*

Proceedings of 10th OECD/NEA Information Exchange Meeting on Actinide and Fission Product Partitioning and Transmutation (CD-ROM), 9 Pages, 2010/00

Information on phase diagram and thermodynamic data of transuranium (TRU) alloys are required for the development of metallic fuel fabrication technology and fuel design for TRU transmutation. In the present study, TRU alloys were prepared from their mixed oxides to establish these informations. A few grams of mother alloys containing TRU elements were prepared from their mixed oxides in the electrochemical reduction method. However, it was found in the electrochemical reduction of PuO that only the sample surfaces were reduced to metal. It is anticipated that the electrochemical conversion of mixed oxides with high Np and Pu contents into metals are difficult owing to production of low-melting metals. Thus, the Li reduction method was applied to the reduction of mixed oxides with high TRU contents and the alloys with high Np and Pu contents were prepared.