Modelling of the LTDE-SD radionuclide diffusion experiment in crystalline rock at the sp Hard Rock Laboratory (Sweden)

Soler, J. M.*; Meng, S.*; Moreno, L.*; Neretnieks, I.*; Liu, L.*; Keklinen, P.*; Hokr, M.*; ha, J.*; Vetenk, A.*; Reimitz, D.*; et al.

Geologica Acta, 20(7), 32 Pages, 2022/07

https://doi.org/10.1344/GeologicaActa2022.20.7

Task 9B of the SKB Task Force on Modelling of Groundwater Flow and Transport of Solutes in fractured rock focused on the modelling of experimental results from the LTDE-SD in situ tracer test performed at the sp Hard Rock Laboratory in Sweden. Ten different modelling teams provided results for this exercise, using different concepts and codes. Three main types of modelling approaches were used: (1) analytical solutions to the transport-retention equations, (2) continuum-porous-medium numerical models, and (3) microstructure-based models accounting for small-scale heterogeneity (i.e. mineral grains and microfracture distributions). The modelling by the different teams allowed the comparison of many different model concepts, especially in terms of potential zonations of rock properties (porosity, diffusion, sorption), such as the presence of a disturbed zone at the rock and fracture surface, the potential effects of micro- and cm-scale fractures.

A Pseudo-material method for graphite with arbitrary porosities in Monte Carlo criticality calculations

Okita, Shoichiro; Nagaya, Yasunobu; Fukaya, Yuji

Journal of Nuclear Science and Technology, 58(9), p.992 - 998, 2021/09

https://doi.org/10.1080/00223131.2021.1899997

Comparative modeling of an in situ diffusion experiment in granite at the Grimsel Test Site

Soler, J. M.*; Landa, J.*; Havlov, V.*; Tachi, Yukio; Ebina, Takanori*; Sardini, P.*; Siitari-Kauppi, M.*; Eikenberg, J.*; Martin, A. J.*

Journal of Contaminant Hydrology, 179, p.89 - 101, 2015/08

https://doi.org/10.1016/j.jconhyd.2015.06.002

Matrix diffusion is a key process for radionuclide retention in crystalline rocks. An in-situ diffusion experiment in granite matrix was performed at the Grimsel Test Site (Switzerland). Several tracers (HTO, Na, Cs) were circulated through a borehole and the decrease in tracer concentrations was monitored for 2.5 years. Then, the borehole section was overcored and the tracer profiles in the rock were analyzed. Transport distances in the rock were 20 cm for HTO, 10 cm for Na and 1 cm for Cs. The dataset was analyzed with diffusion-sorption models by different teams using different codes, with the goal of obtaining effective diffusivities (De) and rock capacity factors. There was a rather good agreement between the values from different teams, implied that De and capacity factors in the borehole damaged zone are larger than those in the bulk rock. However, HTO seems to display large discrepancies between measured and modeled results.

Rim structure formation of isothermally irradiated UO fuel discs

Une, Katsumi*; Nogita, Kazuhiro*; Shiratori, Tetsuo; Hayashi, Kimio

Journal of Nuclear Materials, 288(1), p.20 - 28, 2000/09

https://doi.org/10.1016/S0022-3115(00)00712-1

no abstracts in English

Density, porosity and grain size, 1; Unirradiated ROX fules

Yanagisawa, Kazuaki; Yamashita, Toshiyuki; Kanazawa, Hiroyuki; Amano, Hidetoshi; Muromura, Tadasumi

Journal of Nuclear Science and Technology, 36(11), p.1052 - 1063, 1999/11

https://doi.org/10.3327/jnst.36.1052

no abstracts in English

A Method of estimation bulk density of high-grade uranium ore

Iida, Yoshimasa

Donen Giho, (104), p.135 - 140, 1997/12

https://jopss.jaea.go.jp/pdfdata/PNC-TN1340-97-004.pdf

Uranium ore in the Athabasca region, Canada, is highly variable in density. This is due to large variations in the grade of high-density uranium and associated metalliferous minerals, and also to changes in porosity. As it is not practical to take accurate measurements of dry bulk density values of a large number of samples. As a result of investigation on actual ore samples, it has been found practical to estimate the dry bulk density of ore from measured wet bulk density and grain density calculated from chemical data.

The Open porosity of nuclear graphites measured by the mass-spectrometric technique

Yogyo Kyokia-Shi, 94(1093), p.1012 - 1014, 1986/09

https://doi.org/10.2109/jcersj1950.94.1093_1012

no abstracts in English

Determination of effective conductivity of porous ceramic separators of LiAl/LiCl-KCl/FeS sells

; H.Shimotake*

Proc.Symp.on Lithium Batteries, p.404 - 411, 1981/00

no abstracts in English

Densification of uranium dioxide fuel pellets, (1)

; ; Ichikawa, Michio

JAERI-M 6904, 23 Pages, 1977/02

JAERI-M-6904.pdf:1.02MB

no abstracts in English

Characteristics of two-phase pressure drop in a simulated debris bed

Ito, Daisuke*; Kurisaki, Tatsuya*; Ito, Kei*; Saito, Yasushi*; Aoyagi, Mitsuhiro; Matsuba, Kenichi; Kamiyama, Kenji

no journal, , 

In order to evaluate characteristics of debris-bed coolability in the core region, characteristics of the pressure loss in the debris-bed under liquid-gas two phase flow is required to be understood. In this study, effects of porosity distribution on pressure loss and void-fraction distribution in the test section are presented.