Bayesian sparse modeling of extended X-ray absorption fine structure to determine interstitial oxygen positions in yttrium oxyhydride epitaxial thin film

Kumazoe, Hiroyuki*; Igarashi, Yasuhiko*; Iesari, F.*; Shimizu, Ryota*; Komatsu, Yuya*; Hitosugi, Taro*; Matsumura, Daiju; Saito, Hiroyuki*; Iwamitsu, Kazunori*; Okajima, Toshihiko*; et al.

AIP Advances (Internet), 11(12), p.125013_1 - 125013_5, 2021/12

https://doi.org/10.1063/5.0071166

Observation of iron silicide formation by plan-view transmission electron microscopy

Igarashi, Shinichi*; Haraguchi, Masaharu*; Aihara, Jun; Saito, Takeru*; Yamaguchi, Kenji; Yamamoto, Hiroyuki; Hojo, Kiichi

Journal of Electron Microscopy, 53(3), p.223 - 228, 2004/08

https://doi.org/10.1093/jmicro/53.3.223

no abstracts in English

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.

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.

Current status of application to meet new regulations and expansion of irradiation capabilities after restart

Saito, Hiroto; Yamamoto, Masaya; Someya, Hiroyuki*; Itagaki, Wataru; Maeda, Shigetaka; Takamatsu, Misao

no journal, , 

Toward restart, the experimental fast reactor Joyo is now under the safety review by regulatory body. After restart, we would like to play a enhanced role of fast neutron irradiation experiments. In order to discuss with irradiation materials researchers, introduce the irradiation capabilities of Joyo after restart.