Waste Disposal Project Research Articles

Upscaling THM modeling from small-scale to full-scale in-situ experiments in the Callovo-Oxfordian claystone

The coupled Thermo-Hydro-Mechanical (THM) behavior of the Callovo-Oxfordian claystone (COx) is of great importance for the design and safety calculations of the high-level radioactive waste disposal project in this potential host rock in France. The heat emitted by the waste causes a pore pressure increase within the surrounding rock essentially due to the differential thermal expansion of the pore water and the solid skeleton. The low permeability of the COx and its relative rigidity inhibits the discharge of the induced pressure build-up. Moreover, thermal loading may provoke thermo-mechanical stresses within the formation due to mechanical confinement by the rigidity of the surrounding host rock. An important research program has been conducted by the French National Radioactive Waste Management Agency (Andra) since 2003 in order to investigate the THM response of the COx under thermal loading, through laboratory tests, in-situ experiments, model development and numerical modeling. Within Task E of the DECOVALEX-2019 project, five research teams investigated upscaling THM modeling from a small-scale in-situ experiment (TED) to a full-scale in-situ experiment (ALC). The upscaling modeling started with a verification test to validate the numerical codes. Then, an interpretative modeling of the TED experiment was performed to calibrate the THM parameters of the COx. Finally, the calibrated THM parameters were used for a blind prediction of the ALC experiment. The modeling teams each adopted a thermo-poro-elastic approach which yielded satisfactory results. The blind prediction of the temperature field showed an overestimation of less than 2 °C which was considered acceptable. On the other hand, pore pressure was well predicted only in the direction parallel to the bedding whereas the slow dissipation of the pore pressure in the direction perpendicular to the bedding was not captured by any of the modeling teams – which remains an open question of the present study.

A boundary element formation for three-dimensional thermo-elasticity of a semi-infinite space with buried decaying heat sources

The nuclear waste disposal project involves thermo-mechanical interactions in rock induced by buried decaying heat sources. To satisfy the condition of zero stress on ground surface, mirror heat sinks and boundary solutions are used. Specifically, mirror heat sinks are aimed at removing normal tractions at ground surface generated by heat sources, and boundary solutions are intended for handling residual tangential stresses on ground surface caused by heat sinks and heat sources. Multitudes of rectangles are employed to discretize the ground surface. Under the assumption of evenly distributed shear loads over a rectangular element, an analytical formula about the influence coefficient is derived. Simplifying cylindrical canister heat sources into finite line ones, a repository-scale model for evaluating the thermo-elastic response of rock is proposed. Given a conceptual nuclear waste repository, the temperature increment, thermal stress and displacement of surrounding rock are investigated. The results demonstrate that the present model provides an efficient tool to analyze the thermo-mechanical response of a geologic repository with different heat loading patterns.

Sweetness and HPOWER: Waste, Sugar and Ecological Identity in the Development of Honolulu’s HPOWER Waste-to-Energy Facility

Abstract Recent studies have demonstrated the high spatial, economic and ecological stakes of solid waste management in remote island environments, like Hawaii, but also suggested ways in which conceptions of risk and identity have factored into stakeholders’ decisions regarding particular waste management technologies and processes. Through an analysis of historical and archival documents, this article examines linkages between a declining sugar plantation industry and the development of a major waste disposal project, and shows how an ecological identity narrative which combined an understanding of Honolulu as a place needing to reduce reliance on imported resources with an understanding of metropolitan Honolulu as a major centre for plantation sugarcane agriculture resulted in a plan for combining waste disposal with sugarcane processing. Focused on the historical case of the HPOWER facility on the Hawaiian island of Oahu, I argue that ecological identity offers new insights for understanding how environmental infrastructures are conceptualised and resisted, and that explicit consideration of ecological identity in the analysis of environmental governance may lead to improved scholarly understanding as well as improved outcomes for governance itself.

Experimental Study on Characteristics and Mechanism of Macrography and Mesoscopic Failure of Deep Granite from Beishan

Because of its good stability, high strength and low permeability, granite is considered as an ideal surrounding rock for geological disposal of high-level radioactive waste, which is also the main candidate surrounding rock for high-level radioactive waste disposal project in China. Rock mechanics is one of the important problems for site selection, design, construction and operation of geological repository. It is of great theoretical and practical value to study the failure law of rock from the microcosmic aspect, to link the microcosmic failure morphology characteristics with the mechanical mechanism of rock macro fracture failure, and finally to establish a bridge between microcosmic failure mechanism and macro fracture analysis of rock. We carried out uniaxial compression test, triaxial compression test under different confining pressures, Brazilian splitting test and direct tensile test for the deep granite from the core of No. BS28 hole in Beishan area with depth of 560–680 m. SEM and EDS was carried out for the fracture surface under different test conditions. The macro and micro failure characteristics of granite under different test conditions are analyzed: It is basically the splitting failure phenomenon dominated by tensile failure after the uniaxial compression test, while the failure of the triaxial test specimen are basically all form a large inclined failure surface which show the shear failure phenomenon. It shows obvious brittle tensile failure under direct tensile test, while not simply tensile failure under Brazil split test. The micro structure and mineral composition of rocks are closely related to their macro mechanical properties. Due to the existence of other impurities, Beishan granite has a certain degree of discreteness, and because of the different composition, its fracture presents different forms. These studies provide the necessary basis for the design and construction of the geological disposal of high-level radioactive waste.

The application of the yield approach to study slurry migration in drill cuttings waste underground disposal

The underground disposal of drill cuttings waste is a common practice for the gas/oil industry to achieve zero-discharge sustainable development. In this study, a numerical modeling approach was developed to simulate the slurry flow for underground disposal of drill cuttings waste. The modeling approach was coupled with and implemented in the well-known general purpose subsurface multiphase flow simulator, TOUGH2. The new modeling approach treats the slurry flow behavior in subsurface systems as Bingham plastic liquid, with a linear relationship representing the yield stress and the concentration of the gelatinizer in the slurry. In addition, the precipitation-dissolution process was taken into account for solid-aqueous phase changes of the water-slurry mixture under and over the threshold pressure. The model has been verified by the analytical solution of a transient flow of single-phase Bingham fluid, and has further been tested by modeling field-scale injection of drill cutting wastes into a multi-layered geological formation in Texas. A hypothetical model has also been used to conduct sensitivity analysis of the impact of slurry density, injection depth and injection pattern on the storage formation performance. The results revealed that the effect of injection volume is greater than the mass on pressure buildup. In addition, a short period of intermittent reinjection can lead to an earlier formation breakdown due to particle sedimentation and reduce the storage capacity. The developed model can be used to evaluate the prediction of slurry transport, storage capacity, pressure distribution, and the formation breakdown time in a drill cuttings waste disposal project.

UNIAXIAL COMPRESSION TEST AND NUMERICAL STUDIES OF GRAIN SIZE EFFECT ON MECHANICAL PROPERTIES OF GRANITE

The whole world has paid more attention to the geological disposal of high-level radioactive waste. Granite is the candidate surrounding rock of high-level radioactive waste disposal project in China. It is very important to understand the strength and destructive characteristics of granite in the design and performance evaluation of disposal system. As aggregates of mineral grains, granite is a heterogeneous rock composed of minerals such as quartz, feldspar and biotite, and the macroscopic mechanical behaviors of rock is obviously affected by mineral grain size. Taking the granites in pre-selected Alxa area of China's high-level geological repository as example, the rock samples have obvious difference in grain size. The effect of grain size on granite mechanical properties is studied using uniaxial compression experiments with the combination of numerical simulation. Uniaxial compression experiments are conducted on MTS815 rock mechanics test system and numerical simulations are based on the particle flow code PFC2D. In the process of numerical simulation, the actual spatial distribution of various components within the rock ISS obtained by image processing based on the surface image of the specimen. The particle flow model of granite based on the actual distributions is thereafter established. The model is used to simulate the uniaxial compression test of granite, and the reliability of the model is demonstrated by comparison with the experimental results. Experiment and simulation results show that the failure mode of Alxa granite is brittle and tensional. Most failure is parallel to the direction of compressive stress. Numerical simulation based on digital image processing method can be used to calculate the mechanical responses of rock materials with high efficiency and accuracy. Mineral grain size has little effect on elastic modulus and Poisson's ratio of the rock, but peak strength is obviously affected by the grain size. The main results are as follows:The strength of rock with fine grained and equigranular texture is high, and the strength of rock with coarse grained and inequigranular texture is low.

A Method for Estimating the Highest Potential Hydraulic Conductivity in the Excavation Damaged Zone in Mudstone

Excavation of deep underground openings induces permeable fractures around the opening due to stress redistribution. Such a zone is called excavation damaged zone (EDZ). In a high-level radioactive waste disposal project, the EDZ might provide pathways for the migration of radionuclides around the facility. Thus, this study focused on the development of a method for estimating the highest potential hydraulic conductivity in the EDZ around a gallery in the Horonobe Underground Research Laboratory, Japan. Borehole televiewer surveys, rock core observations, and hydraulic tests were undertaken to investigate the extent and magnitude of hydraulic conductivity in the EDZ around the gallery. The observed extent (sidewall ≤ 0.6 m; floor ≤ 1.6 m) of the EDZ shows good agreement with the EDZ estimated from hydro-mechanical coupling analysis. The measured hydraulic conductivities of the EDZ (3.5 × 10−6 to 1.24 × 10−8 m/s) are within the range of those based on the Mean Stress Index (MSI), which is defined as the ratio of the effective mean stress derived from numerical analyses to the tensile strength of intact rock. Given that the rock mass is relatively homogeneous and artificial damage (e.g., blasting-induced damage) can be neglected, as in the Horonobe Underground Research Laboratory, the MSI model is likely to be applicable in estimating the highest potential hydraulic conductivity in the EDZ.

Modelling of anisotropic damage due to hydrogen production in radioactive waste disposal

The production of hydrogen due to metallic container corrosion is one of the most critical problems related to an underground radioactive waste disposal project. In fact, the increasing hydrogen pressure in the porous network of the host rock may lead to a mechanical damage and consequently increase the risk of environment contamination. This paper proposes an approach to studying this phenomenon by using a hydromechanical model, which accounts for the hydrogen and water flows, the anisotropic mechanical damage and the anisotropic damage-induced permeability change. For a given geometry and material characteristics, a parametric study on the quantity of the produced hydrogen was conducted. Namely, the time of the damage initiation and the extent of the damaged zone were considered. A threshold on the produced quantity, below which the host rock was not damaged, was obtained. This value was found to be considerably higher than the estimates obtained by some studies concerning the corrosion reactions, which is encouraging for the repository project reliability.

Modelling of chemical degradation of blended cement-based materials by leaching cycles with Callovo-Oxfordian porewater

The present work describes a thermodynamic model based on pore water replacement cycles to simulate the chemical evolution of blended cement (BFS + FA) by interaction with external Callovo-Oxfordian (COx) pore water. In the framework of the radioactive waste management, the characterization of the radionuclide behaviour (solubility/speciation, adsorption) in cementitious materials needs to be done for several chemical degradation states (I to IV). In particular, in the context of the deep geological radioactive waste disposal project (Cigéo), cement-based materials will be chemically evolved with time in contact with the host-rock (COx formation). The objective of this study is to provide an equilibrium solution composition for each degradation state for a CEM-V cement-based material to support the adsorption and diffusion experiments reproducing any state of degradation. Calculations have been performed at 25 °C using the geochemical code PhreeqC and an up-to-date thermodynamic database (ThermoChimie v.9.0.b) coupled to SIT approach for ionic strength correction. The model replicates experimental data with accuracy. The approach followed in this study eases the analysis of the chemical evolution in both aqueous and solid phase to obtain a fast assessment of the geochemical effects associated to an external water intrusion of variable composition on concrete structures.

Biological removal effect for odor in medical waste steam treatment process

Malodorous gas will be produced in medical waste steam treatment process, which mainly consist of volatile organic compounds. Biological deodorization is a low cost deodorization technology. In this paper, biological deodorization technology in an actual medical waste disposal project was studied, and its removal efficiencies of VOCs were analyzed. The contents of four volatile organic compounds in exhaust gas were determined by gas chromatography and methylene blue spectrophotometry. The average concentration of them were: methyl-sulfhydryl 0.037mg/m3, dimethyl sulfide 0.046mg/m3, methyl disulfide 0.904mg/m3 and hydrogen sulfide 0.204mg/m3. After they were treated by biological deodorization, the average removal rates of the four compounds were methyl-sulfhydryl 93%, dimethyl sulfide 92.6%, methyl disulfide 97.6% and hydrogen sulphide 92.6%.The results showed that the four kinds of VOCs had good deodorization effect, and the national standards for emissions requirements can be met well.

豊島廃棄物等処理事業における処分地管理手法の高度化に関する検討

This report shows the development of a management method of Teshima waste disposal project using GPSbased 3D modeling method. Teshima waste disposal project has been conducted since 2003 as a solution of the illegal industrial waste dumping occurred in Teshima-island, Kagawa Prefecture. To prevent illegal dumping and to accumulate data of this project, we took a survey of the disposal area 4 times a year and made the 3D model of the area. By comparing the 3D model change in time course, we can show stakeholders how the project has advanced. And by surveying the area changed between the two 3D models, we can calculate the volume of disposed garbage. So, we call this system a “Co-creation system”. Therefore, we compared the cost and accuracy of GPS surveying, Light wave surveying, and Laser surveying. With this system we promoted information sharing between stakeholders.

A Comprehensive Review of Environmental, Physical and Socio-Economic (EPSE) Criteria for Spatial Site Selection of Landfills in Malaysia

Location of municipal solid waste landfills in Malaysia has been attributed to causing bad odour, dust, litter, unattractive neighbourhoods, groundwater contamination, hazardous waste pollution and etc. Therefore, proper selection criteria are very important in preliminary siting of new landfill to avoid undesirable long-term effects. This article presents a comprehensive review of landfill spatial siting criteria and their frequency of occurrence (ranked order) found in literatures. The highest ranked criterion is the surface water and the lowest is climate/rainfall density. The dissimilarity in the criteria is found to be specifically influenced by published guidelines or policies from respective countries. In addition, group ranking of spatial criteria from frequency study made on Malaysian local literatures shows that wind factor and infrastructure (utilities) has never been considered in landfill site selection process here. These factors cannot be ignored because enhancing the condition of social, economic and environmental efficiency is part of promoting sustainable development. Subsequently, a benchmarking process of common environmental, physical and socio-economic (EPSE) criteria made with Malaysian landfill siting guideline; National Strategic Plan for Solid Waste Management and Environmental Impact Assessment Guidelines for Municipal Solid Waste and Sewage Treatment and Disposal Project. The bench mark process is useful for research references and its uniformity provides efficient site selection process in solid waste management.

Rapid impact assessment matrix (RIAM) analysis as decision tool to select new site for municipal solid waste disposal: A case study of Dehradun city, India

Abstract The selection of appropriate site for creation of new MSW disposal facility is an important task of waste management engineering. The ecological, social and economical issues pertaining to new project should be analyzed in order to measure the overall impact of the new waste disposal project. In this study rapid impact assessment matrix (RIAM) which comes under one of the options of environmental impact assessment (EIA) was used to see the overall rating of the site to establish a possible new MSW disposal site for the city. The suitability of the site was evaluated considering ecological, social, cultural and economical as components in decision support system. Different components were used to produce a cumulative score, i.e. environmental score (ES) for each option of the site for the new project. Results suggests that RIAM can be a reliable tool to identify the suitability of the site for MSW disposal facility creation in accordance with ecological, physical, biological, social/cultural and economic quality of the project. In this city, for physical/chemical component the forest distribution was the major factor in site selection while biological/ecological components showed the negative impact of project in all sub-sectors. Socio-cultural and economical components showed the different ranges of ES. This study extends the possibility of utilizing RIAM as tool in decision supporting system for establishing MSW disposal facilities in any urban center.

214 豊島廃棄物等処理事業におけるGISを活用した事業の進捗業況の3Dモデル化とその活用(環境マネジメント・手法(2))

Teshima waste disposal project has been done as a solution of the illegal industrial waste dumping occurred in Teshima-island, Kagawa Prefecture since 2003. The role of the watch of the project is requested by the resident living in Teshima-island and Naoshima-island. 0n the other hand, disclosing useful information for the understanding this project is by whom is the entrepreneur needed in Kagawa Prefecture. Both of information matched to the progress of the project, Co-creation system is thought to be necessary by such correspondence. We have aimed to practice what we can do as an engineer, and we made the 3D model of the waste dumping place to show how the project has progressed. The goal Of our study is to prevent illegal dumping and to accumulate data about l'eshima waste disposal project. In this report, we show development of 3D modeling method ofTeshima waste disposal project by GIS.

放射性廃棄物処分の専門的知見集積に関するコミュニケーションの観点からの一考察

Technical knowledge and information on the geological disposal of radioactive waste should be readily understandable for stakeholders who make decisions on implementation of the disposal so that those would be effectively contributory to the decision-making process. To realise reasonable understanding and decisions on the radioactive waste disposal project, it is suggested to be effective and necessary that producing knowledge and information is carried out interactively with crystallizing variable requirements and concerns from stakeholders, rather than by giving technical information in only one direction even if it can be provided in detail. In this study, a communication methodology of knowledge management on radioactive waste disposal based on analysis of a series of dialogue experiments with citizens and a case study of discussion by political experts on the geological disposal project of high-level radioactive waste and TRU waste in Japan is discussed. It seems reasonable to conclude that there is a common process of stepwise understanding, in which stakeholders need general knowledge and information on the concerned issue in the first step and then obtain more specific knowledge to make decision in the later steps. In the knowledge management concept, it is suggested that the key issues are how to correct and arrange knowledge and information, not only technical ones but also political, economical and so on, by applying the methodology of interactive accumulation of them between stakeholders.

Ｘ線ＣＴ法による亀裂内トレーサー移行プロセスの可視化と分析

The advection and dispersion of contaminated materials in a rock mass are one of the important factors to evaluate the characteristics of the rock mass as a natural barrier function for a radioactive waste disposal project. In this study, X-ray CT method was applied to evaluate the advection and dispersion of solute in the crack which exists in rock mass. In order to visualize advection and dispersion phenomena, the tracer migration test have been conducted and tracer migration process was visualized by X-ray CT scanner. Here, an indicator, coefficient of tracer density increment, was newly introduced to analyze tracer migration. This is the indicator that represents the density of the tracer in the crack, and the evaluation of the density distribution of the tracer becomes possible. In this study, the influences of the crack aperture to the tracer migration process are discussed.

The Landfill Area Quality (LAQ) Classification Approach and Its Application in Isparta, Turkey

The amount of residential and industrial solid waste, and the need for landfill sites, is ever growing due to increases in population and industrial production. Landfilling is a widely used method for environmentally safe disposal of solid waste, and the selection of the most suitable landfill site is a very crucial decision. In this study, a new site evaluation method to determine suitable landfill sites, called Landfill Area Quality (LAQ), is introduced. This method is applied in two stages. First, several potential landfill sites, which are within legally permissible areas, are chosen by a general consideration of the relevant site properties. Then, the characteristics of these chosen sites are placed within three-dimensional evaluation spaces. These evaluative dimensions are (1) site suitability, (2) location factors, and (3) public acceptability, and each is defined by a combination of different criteria. The result of this re-evaluation, which provides valuable information to planning engineers and decision makers about the available sites, is reported to decision makers for the final selection. A detailed case study was carried out as part of a residential solid waste disposal project for the city of Isparta in Turkey, (population 150,000), and was very useful to planners.

Micromechanics-based prediction of creep failure of hard rock for long-term safety of high-level radioactive waste disposal system

A high-level radioactive waste disposal project is under way in Japan. Isolation of the radioactive waste in a rock formation at great depth is considered as one of the promising disposal methods. Before proceeding with the disposal project, however, assessment of the long-term stability of rock mass surrounding waste packages is necessary. This paper presents a micromechanics-based model for predicting the creep failure of hard rock under compression. The subcritical crack growth due to stress corrosion cracking and interaction effects between cracks are considered as the main mechanisms of creep failure. An evolution problem of two interacting cracks is formulated and creep failure following tertiary creep is represented as unstable extension of the interacting cracks in the present model. The time to failure is calculated for different values of axial stress, confining pressure, and environmental conditions such as temperature and presence of water. The effects of water, temperature, and stress states on the long-term behavior are also included in the proposed model.

Waste Isolation Pilot Plant: Retrieving Nuclear Waste Disposal Information

Accessing documents pertaining to nuclear waste can be a complex process. This bibliographic essay examines the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico, as an example of the numerous publications which arise from one nuclear waste disposal project. This article examines the history of the WIPP, the government agencies and contractors that publish documents and dockets, and the indices, hotlines, and catalogs necessary for access.

A review of the ANDRA's research programmes on the thermo-hydromechanical behavior of clay in connection with the radioactive waste disposal project in deep geological formations : B. Felix, P. Lebon, R. Miguez & F. Plas, Engineering Geology, 41(1–4), 1996, pp 35–50

A review of the ANDRA's research programmes on the thermo-hydromechanical behavior of clay in connection with the radioactive waste disposal project in deep geological formations : B. Felix, P. Lebon, R. Miguez & F. Plas, Engineering Geology, 41(1–4), 1996, pp 35–50