Delphine Durce , Marc Aertsens , Norbert Maes , Marc Van Gompel , Stéphane Brassinnes
{"title":"测定布姆粘土中非反应性示踪剂扩散系数的实验室规模实验比较","authors":"Delphine Durce , Marc Aertsens , Norbert Maes , Marc Van Gompel , Stéphane Brassinnes","doi":"10.1016/j.apgeochem.2024.106101","DOIUrl":null,"url":null,"abstract":"<div><p>The transport parameters of radionuclides, the diffusion coefficient and the retardation factor, in clay-rich host rocks investigated for deep geological disposal, can be determined using various types of laboratory experiments. The present study aimed at comparing three types of laboratory experiments commonly used in the context of radioactive waste for the determination of the transport properties of two non-reactive tracers, HTO and <sup>125</sup>I, in Boom Clay. Two Boom Clay samples with orientation parallel and perpendicular to the bedding were selected to assess the role of sample heterogeneity and anisotropy. Each sample/orientation was subjected to through-diffusion experiments, pulse injection experiments with pressure differences over the clay core ranging from 5 to 19 bars and a back-to-back experiment.</p><p>In the case of HTO, the three types of experiments led to a consistent set of transport parameters for each Boom Clay sample. Over the three types of experiment, the average apparent diffusion coefficients and accessible porosity vary at maximum a factor 1.4 and 1.3, respectively for a same sample type/orientation. The porosity accessible to HTO was similar to the porosity calculated from the water content. In the case of <sup>125</sup>I, the three types of experiments also showed consistency for the determination of the apparent diffusion coefficients with values varying within a factor 1.7 for the same sample type/orientation. However, variation in accessible porosity between the experiments revealed a physical modification of the Boom Clay sample occurring during the pulse injection experiments and affecting <sup>125</sup>I transport.</p><p>Transport anisotropy was consistently observed in all the types of experiment and for both HTO and <sup>125</sup>I with a higher anisotropy observed in the samples richer in clay. Slightly higher total porosity and lower <sup>125</sup>I accessible porosity were noticed in the clay-rich samples in comparison to silt-rich samples.</p></div>","PeriodicalId":8064,"journal":{"name":"Applied Geochemistry","volume":"173 ","pages":"Article 106101"},"PeriodicalIF":3.1000,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Comparison of lab-scale experiments for the determination of non-reactive tracer diffusion coefficients in Boom Clay\",\"authors\":\"Delphine Durce , Marc Aertsens , Norbert Maes , Marc Van Gompel , Stéphane Brassinnes\",\"doi\":\"10.1016/j.apgeochem.2024.106101\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The transport parameters of radionuclides, the diffusion coefficient and the retardation factor, in clay-rich host rocks investigated for deep geological disposal, can be determined using various types of laboratory experiments. The present study aimed at comparing three types of laboratory experiments commonly used in the context of radioactive waste for the determination of the transport properties of two non-reactive tracers, HTO and <sup>125</sup>I, in Boom Clay. Two Boom Clay samples with orientation parallel and perpendicular to the bedding were selected to assess the role of sample heterogeneity and anisotropy. Each sample/orientation was subjected to through-diffusion experiments, pulse injection experiments with pressure differences over the clay core ranging from 5 to 19 bars and a back-to-back experiment.</p><p>In the case of HTO, the three types of experiments led to a consistent set of transport parameters for each Boom Clay sample. Over the three types of experiment, the average apparent diffusion coefficients and accessible porosity vary at maximum a factor 1.4 and 1.3, respectively for a same sample type/orientation. The porosity accessible to HTO was similar to the porosity calculated from the water content. In the case of <sup>125</sup>I, the three types of experiments also showed consistency for the determination of the apparent diffusion coefficients with values varying within a factor 1.7 for the same sample type/orientation. However, variation in accessible porosity between the experiments revealed a physical modification of the Boom Clay sample occurring during the pulse injection experiments and affecting <sup>125</sup>I transport.</p><p>Transport anisotropy was consistently observed in all the types of experiment and for both HTO and <sup>125</sup>I with a higher anisotropy observed in the samples richer in clay. Slightly higher total porosity and lower <sup>125</sup>I accessible porosity were noticed in the clay-rich samples in comparison to silt-rich samples.</p></div>\",\"PeriodicalId\":8064,\"journal\":{\"name\":\"Applied Geochemistry\",\"volume\":\"173 \",\"pages\":\"Article 106101\"},\"PeriodicalIF\":3.1000,\"publicationDate\":\"2024-07-15\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Applied Geochemistry\",\"FirstCategoryId\":\"89\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0883292724002063\",\"RegionNum\":3,\"RegionCategory\":\"地球科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"GEOCHEMISTRY & GEOPHYSICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Applied Geochemistry","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0883292724002063","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
Comparison of lab-scale experiments for the determination of non-reactive tracer diffusion coefficients in Boom Clay
The transport parameters of radionuclides, the diffusion coefficient and the retardation factor, in clay-rich host rocks investigated for deep geological disposal, can be determined using various types of laboratory experiments. The present study aimed at comparing three types of laboratory experiments commonly used in the context of radioactive waste for the determination of the transport properties of two non-reactive tracers, HTO and 125I, in Boom Clay. Two Boom Clay samples with orientation parallel and perpendicular to the bedding were selected to assess the role of sample heterogeneity and anisotropy. Each sample/orientation was subjected to through-diffusion experiments, pulse injection experiments with pressure differences over the clay core ranging from 5 to 19 bars and a back-to-back experiment.
In the case of HTO, the three types of experiments led to a consistent set of transport parameters for each Boom Clay sample. Over the three types of experiment, the average apparent diffusion coefficients and accessible porosity vary at maximum a factor 1.4 and 1.3, respectively for a same sample type/orientation. The porosity accessible to HTO was similar to the porosity calculated from the water content. In the case of 125I, the three types of experiments also showed consistency for the determination of the apparent diffusion coefficients with values varying within a factor 1.7 for the same sample type/orientation. However, variation in accessible porosity between the experiments revealed a physical modification of the Boom Clay sample occurring during the pulse injection experiments and affecting 125I transport.
Transport anisotropy was consistently observed in all the types of experiment and for both HTO and 125I with a higher anisotropy observed in the samples richer in clay. Slightly higher total porosity and lower 125I accessible porosity were noticed in the clay-rich samples in comparison to silt-rich samples.
期刊介绍：
Applied Geochemistry is an international journal devoted to publication of original research papers, rapid research communications and selected review papers in geochemistry and urban geochemistry which have some practical application to an aspect of human endeavour, such as the preservation of the environment, health, waste disposal and the search for resources. Papers on applications of inorganic, organic and isotope geochemistry and geochemical processes are therefore welcome provided they meet the main criterion. Spatial and temporal monitoring case studies are only of interest to our international readership if they present new ideas of broad application.
Topics covered include: (1) Environmental geochemistry (including natural and anthropogenic aspects, and protection and remediation strategies); (2) Hydrogeochemistry (surface and groundwater); (3) Medical (urban) geochemistry; (4) The search for energy resources (in particular unconventional oil and gas or emerging metal resources); (5) Energy exploitation (in particular geothermal energy and CCS); (6) Upgrading of energy and mineral resources where there is a direct geochemical application; and (7) Waste disposal, including nuclear waste disposal.
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