Rotation of complex ions with ninefold hydrogen coordination studied by quasielastic neutron scattering and first-principles molecular dynamics calculations

Omasa, Yoshinori*; Takagi, Shigeyuki*; Toshima, Kento*; Yokoyama, Kaito*; Endo, Wataru*; Orimo, Shinichi*; Saito, Hiroyuki*; Yamada, Takeshi*; Kawakita, Yukinobu; Ikeda, Kazutaka*; et al.

Physical Review Research (Internet), 4(3), p.033215_1 - 033215_9, 2022/09

https://doi.org/10.1103/PhysRevResearch.4.033215

LiFeH; Iron-containing complex hydride with high gravimetric hydrogen density

Saito, Hiroyuki; Takagi, Shigeyuki*; Matsuo, Motoaki*; Iijima, Yuki*; Endo, Naruki*; Aoki, Katsutoshi*; Orimo, Shinichi*

APL Materials (Internet), 2(7), p.076103_1 - 076103_7, 2014/07

https://doi.org/10.1063/1.4886219

Synthesis and formation process of AlCuH; A New class of interstitial aluminum-based alloy hydride

Saito, Hiroyuki; Takagi, Shigeyuki*; Endo, Naruki; Machida, Akihiko; Aoki, Katsutoshi; Orimo, Shinichi*; Katayama, Yoshinori

APL Materials (Internet), 1(3), p.032113_1 - 032113_7, 2013/09

https://doi.org/10.1063/1.4821632

Formation process of perovskite-type hydride LiNiH; synchrotron radiation X-ray diffraction study

Sato, Ryutaro*; Saito, Hiroyuki; Endo, Naruki; Takagi, Shigeyuki*; Matsuo, Motoaki*; Aoki, Katsutoshi; Orimo, Shinichi*

Applied Physics Letters, 102(9), p.091901_1 - 091901_4, 2013/03

https://doi.org/10.1063/1.4794067

Formation of an Fe-H complex anion in YFe; Adjustment of imbalanced charge by additional Li as an electron donor

Matsuo, Motoaki*; Saito, Hiroyuki; Machida, Akihiko; Sato, Ryutaro*; Takagi, Shigeyuki*; Miwa, Kazutoshi*; Watanuki, Tetsu; Katayama, Yoshinori; Aoki, Katsutoshi; Orimo, Shinichi*

RSC Advances (Internet), 3(4), p.1013 - 1016, 2013/01

https://doi.org/10.1039/c2ra22497f

Study on the Development of Geological Environmental Model(II)

Tsujimoto, Keiichi*; Shinohara, Yoshinori*; Saito, Shigeyuki*; Ueta, Shinzo*; Ohashi, Toyo*; Sasaki, Ryoichi*; Shingo, Tomiyama*

JNC TJ8400 2003-039, 395 Pages, 2003/02

JNC-TJ8400-2003-039.pdf:7.74MB

The safety performance assessment was carried out in imaginary geological environment in the conventional research and development of geological disposal, but the importance of safety assessment based on the repository design and considering the concrete geological environment will increase in the future. The research considering the link of the major three fields of geological disposal, investigation of geological environment, repository design and safety performance assessment, is the contemporary worldwide research theme. Hence it is important to organize information flow that contains the series if information process from the data production to analysis in the three fields, and to systemize the knowledge base that unifies the information flow hierarchically.The information flow for geological environment model generation process is examined and modified base on the product of the research of "Study on the development of geological environment model" that of the research in 2002. The work flow diagram for geological structure and hydrology are modified, and those for geochemical and rock property are examined from the search. Furthermore, database design was examined to build geochemical environment database (knowledgebase) based on the result of the systemization of the environment model generation technology. The geochemical environment database was designed and the prototype system is build to contribute database design.

The Study on Uranium Waste Disposal Repository(Phase 2)

Saito, Shigeyuki*; Ikuse, Hiroyuki*

JNC TJ8400 2003-029, 288 Pages, 2003/02

JNC-TJ8400-2003-029.pdf:5.15MB

(1)study on disposal condition of uranium-bearing waste. Performance of daughter nuclides in uranium-bearing disposal (into approximately-100m-depth) is estimated by investigation of differential equation. And relationship between variation of parameter and dose rate is investigated form the point of release coefficient, solubility, infiltration, water velocity, distribution coefficient (Kd), distance to river. Influence to daughter nuclides in case of shift of Kd is investigated. If Kd of daughter nuclides are smaller than that of parent nuclide, daughter nuclides may travel without radioactive equilibrium. Furthermore, the less is the distance to river, the more is maximum dose rate, when assessment duration is limited. (2)study on concentration and flux of natural radioactive elements Concentration data of natural radionuclides and some chemical species have been examined regarding Japanese geological environment by literature survey, and the characteristics of their statistical distributions have been obtained using a method of statistical analysis. Deep considerations have been made on the characteristics and their related factors on each geological environment based on the information of chemical species and geological characteristics. Furthermore, a hypothetical methodology of an assessment of natural fluxes which reflect geological environments in Japan has been presented for a description of credibility and applicability of natural safety indicators by considering a timescale of an assessment, information of data acquisition mehtod and data accumulation, credibility of matter cycle, and differences of areas for the assessment.

Study on the development of geological environmental model

Tsujimoto, Keiichi*; Shinohara, Yoshinori*; Saito, Shigeyuki*; Ueta, Shinzo*; *; *; *

JNC TJ8400 2002-019, 480 Pages, 2002/03

JNC-TJ8400-2002-019.pdf:7.86MB

The safety performance assessment was carried out in potential geological environment in the conventional research and development of geological disposal, but the importance of safety assessment based on the repository design and scenario considering the concrete geological environment will increase in the future. The research considering the link of the major three fields of geological disposal, investigation of geological environment, repository design, and safety performance assessment, is the contemporary worldwide research theme. Hence it is important to organize information flow that contains the series of information process form the data production to analysis in the three fields, and to systemize the knowledge base that unifies the information flow hierarchically. The purpose of the research is to support the development of the unified analysis system for geological disposal. The development technology for geological environmental model studied for the second progress report by JNC are organized and examined for the purpose of developing database system with considering the suitability for the deep underground research facility. The geological environmental investigation technology and building methodology for geological structure and hydro geological structure models are organized and systemized. Furthermore, the quality assurance methods in building geological environment models are examined. Information which is used and stored in the unified analysis system are examined to design database structure of the system based on the organized methodlogy for building geological environmental model. The graphic processing function for data stored in the unified database are examined. Furthermore, future research subjects for the development of detail models for geological disposal are surveyed to organize safety performance system.

The Study on the conceptual design of uranium waste repository (Phase3)

Saito, Shigeyuki*; Ikuse, Hiroyuki*

JNC TJ8400 2002-026, 704 Pages, 2002/02

JNC-TJ8400-2002-026.pdf:33.96MB

(1)study on disposal condition of uranium-bearing waste. Possibility of approximately-100m-depth disposal of various uranium-bearing waste (4.5% enrichment and uranium concentration of 1000 Bq/g) has been studied in order to clear the disposal condition. While exposure rate to the public is over 0.01 mSv/y if all of interested parameters are the worst case, it is less than 0.01 mSv/y only if flow rate in the river is not less than 1E9 m/y, independent of other parameters. In this study, there is no case that exposure rate is less than 0.01 mSv/y for the limit of only one parameter except 1E9 m/y of flow rate in the river. However, less than 0.01 mSv/y is possibly expected in the following case : one is that both inhalation rate and flow rate in the river take reference values, another is that inhalation rate takes reference value and media have good adsorptivity. (2)study on concentration and flux of natural radioactive elements. A literature survey on natural elemental concentrations has been conducted. The collective state of elemental concentration data in Japan is reporterd. To construct methodology of the assessment of natural safety indicators (including flux and concentration), studies on natural geological environments and geological processes in Japan were examined. The methodology of natural safety indicators is divided into the following 6 parts; (a)Geological modeling of assessment area, (b)Gathering of concentraion (,density and radioactivity) data, (c)Research and selection of geological processes (including prosess rate data), (d)Elemental circulation modelling at assessment area, (e)Research of geological repository system and outlines of safety assessment, (f)Setting up of purpose of natural safety indicators, and presentation of the indicators. The international researches of guidelines and laws concerned with natural safety indicators and the review of reserches on the latest natural safety indicators were also examined.

None

Saito, Shigeyuki*; Morooka, Koichi*; *; *; *; *

PNC TJ1211 96-001, 456 Pages, 1996/03

PNC-TJ1211-96-001.pdf:19.7MB

None