Experimental investigation on local flow structures of upward cap-bubbly flows in a vertical large-size square channel

Sun, Haomin; Kunugi, Tomoaki*; Yokomine, Takehiko*; Shen, X.*; Hibiki, Takashi*

Experimental Thermal and Fluid Science, 154, p.111171_1 - 111171_24, 2024/05

https://doi.org/10.1016/j.expthermflusci.2024.111171

Ionic radii in fluorites

Vauchy, R.; Hirooka, Shun; Murakami, Tatsutoshi

Materialia, 32, p.101934_1 - 101934_12, 2023/12

https://doi.org/10.1016/j.mtla.2023.101934

Multi-dimensional characteristics of upward bubbly flows in a vertical large-size square channel

Sun, Haomin; Kunugi, Tomoaki*; Yokomine, Takehiko*; Shen, X.*; Hibiki, Takashi*

International Journal of Heat and Mass Transfer, 211, p.124214_1 - 124214_17, 2023/09

https://doi.org/10.1016/j.ijheatmasstransfer.2023.124214

Development of JAEA sorption database (JAEA-SDB); Update of sorption/QA data in FY2021

Sugiura, Yuki; Suyama, Tadahiro*; Tachi, Yukio

JAEA-Data/Code 2021-017, 58 Pages, 2022/03

JAEA-Data-Code-2021-017.pdf:1.98MB

Sorption behavior of radionuclides (RNs) in buffer materials (bentonites), rocks and cementitious materials is one of the key processes in a safe geological disposal of radioactive waste because RNs migration in these materials is expected to be retarded by the sorption process. Therefore, it is necessary to understand the sorption process and develop a database compiling reliable data and mechanistic/predictive models so that reliable parameters can be set under a variety of geochemical conditions relevant to a performance assessment (PA). For this purpose, Japan Atomic Energy Agency (JAEA) has developed the database of sorption parameters in bentonites, rocks and cementitious materials. This sorption database (SDB) was firstly developed as an important basis for the H12 PA of a high-level radioactive waste disposal, and have been provided through the Web. JAEA has continued to improve and update the SDB in the view of potential future needs of data focusing on assuring the desired quality level and testing the usefulness of the databases for possible applications to the PA-related parameter setting. This report focuses on updating of the sorption database (JAEA-SDB) as a basis of integrated approach for the PA-related distribution coefficient (Kd) setting and development of mechanistic sorption models. This report also includes an overview of the database structure and contents. Kd data and their quality assurance (QA) results were updated from literature collected with wider ranges. As a result, 8,503 Kd data from 70 references related to the above-mentioned systems were added and the total number of Kd values in JAEA-SDB reached 79,072. The QA/classified Kd data reached about 75.4% for all Kd data in JAEA-SDB. The updated JAEA-SDB is expected to make it possible to give a basis for the next-step PA-related Kd setting.

Settings of biospheric dose assessment parameters in safety assessment for final repository of short-lived radioactive waste in Sweden

Kato, Tomoko

KURNS-EKR-11, p.19 - 28, 2021/03

https://www.rri.kyoto-u.ac.jp/PUB/report/09_kurns.html

In order to extract the knowledge that will be helpful in setting the biospheric dose assessment parameters and their database for safety assessment of radioactive waste disposal in Japan, a methodology of setting the biospheric dose assessment parameters was surveyed in the safety assessment of the radioactive waste disposal in Sweden. In this study, the handling in the biospheric dose assessment in SR-PSU was specifically focused. SR-PSU was the project about the safety assessment for final repository of short-lived radioactive waste in Sweden, SFR.

Development of calculation methodology for estimation of radionuclide composition in wastes generated at Fukushima Daiichi Nuclear Power Station

Sugiyama, Daisuke*; Nakabayashi, Ryo*; Koma, Yoshikazu; Takahatake, Yoko; Tsukamoto, Masaki*

Journal of Nuclear Science and Technology, 56(9-10), p.881 - 890, 2019/09

https://doi.org/10.1080/00223131.2019.1595765

Records of physico-chemical parameters by geochemical monitoring system in the Horonobe Underground Research Laboratory

Mezawa, Tetsuya; Mochizuki, Akihito; Miyakawa, Kazuya; Sasamoto, Hiroshi

JAEA-Data/Code 2018-001, 55 Pages, 2018/03

JAEA-Data-Code-2018-001.pdf:10.63MB
JAEA-Data-Code-2018-001-appendix(CD-ROM).zip:8.57MB

Japan Atomic Energy Agency has been conducting "geoscientific study" and "research and development on geological disposal" in the Horonobe Underground Research Laboratory (URL) for safe geological disposal of high-level radioactive waste. Geochemical parameters of groundwater pressure, pH, and oxidation-reduction potential in the deep groundwater has been continuously monitored with monitoring systems which were developed in the Horonobe URL Project. This report presents the physico-chemical parameters of groundwater which have been obtained by the monitoring systems installed at the 140 m, 250 m and 350 m gallery. The data obtained until March 31, 2017 was summarized along with related information such as the specifications of boreholes and the excavation of the URL.

Validation of core cooling capability analysis in Monju during guillotine pipe break at primary heat transport system

Yamada, Fumiaki; Arikawa, Mitsuhiro*; Fukano, Yoshitaka

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05

In sodium-cooled fast reactor, since the coolant does not need to be pressurized, a pipe break due to the internal pressure does not occur physically. For safety margin in Japanese prototype fast breeder reactor (Monju), the guillotine pipe break accident, i.e., loss of integrity (LOPI) has been analyzed as an extreme assumption for beyond design basis accidents (B-DBAs) in the licensing application for the permit. The cooling capability of the core was re-evaluated in this paper during a large-scale, more specifically guillotine pipe break at the primary heat transport system (PHTS) in Monju, newly considering the following latest findings: (a) Experimental data on sodium boiling in fuel assemblies, (b) Actual PHTS pump coast-down characteristics, and (c) Transient burst test data on irradiated fuel claddings. The analysis models were the validated and simulations were re-performed also using the actual Monju data such as the response time to the trip signals, etc. As a result, it was clarified that the ratio of failed fuel claddings does not exceed around 3% of all of fuel assemblies, as in the past licensing analysis. The safety has been reconfirmed to be secured without significant core damage even under an extreme assumption of a double-ended guillotine pipe break at the PHTS in Monju.

Single crystal growth and crystal structure of ThRhIn and LuCoGa

Matsuda, Tatsuma; Haga, Yoshinori; Sakai, Hironori; Ikeda, Shugo; Onuki, Yoshichika

Journal of the Physical Society of Japan, 75(Suppl.), p.85 - 87, 2006/08

Recently quasi-two-dimensional electron state in rare earth and actinide compounds with HoCoGa-type tetragonal crystal structure was attracted a lot attention in relation to heavy fermion superconductivity observed in CeCoIn, CeIrIn and PuCoGa. In order to elucidate the role of electron in these compounds, it is necessary to compare their electronic state with that of lanthanum and thorium compounds which do not possess the -electrons. The number of valence electrons in the thorium compound is the same as that of the corresponding 4-itinerant cerium compound. We have recently tried to make thorium 115 compounds by indium flux method and have succeeded in discovering the new material of ThRhIn. Crystal structure and quality were confirmed by X-ray diffraction, fluorescent X-ray analysis and EPMA. The lattice parameters were determined to be 4.681(6) and , respectively. The positional parameter of In(4) site was also determined to be .

Spectroscopic properties of Yb doped YLF grown by a vertical Bridgman method

Sugiyama, Akira; Katsurayama, Masamichi*; Anzai, Yutaka*; Tsuboi, Taiju*

Journal of Alloys and Compounds, 408-412, p.780 - 783, 2006/02

https://doi.org/10.1016/j.jallcom.2005.01.094

Laser crystals of LiYF (YLF) doped with 5 - 64 at.% of trivalent ytterbium ions (Yb) were grown by a vertical Bridgman method. As crystal growth materials of YbF and YF including YOF impurities caused opaque crystal, the YOF reduction procedure using PbF was essential before starting the crystal growth. We derived seven energy levels from the F and F manifolds of Yb: YLF by the crystal-field analysis from which we explain the observed polarized absorption and emission spectra. The intrinsic broad and complicated spectra of Yb: YLF are attributed to the strong coupling of the 4f electrons with lattice vibration of the crystal.