Developments for in Situ Tests on Compacted Bentonite-Based Buffer Material

1990 ◽  
Vol 212 ◽  
Author(s):  
B. H. Kjartanson ◽  
M. N. Gray ◽  
B.C.M. Pulles
Keyword(s):  
Large Scale ◽  
Large Diameter ◽  
Full Scale ◽  
In Situ Tests ◽  
Buffer Material ◽  
In Situ Experiments ◽  
Buffer Mixture ◽  
Underground Research Laboratory ◽  
Nuclear Fuel Waste

ABSTRACTAECL Research is carrying out large-scale in situ experiments at its Underground Research Laboratory (URL). The Buffer/Container Experiment is designed principally to investigate the full scale, in situ performance of bentonite-based buffer material in a single emplacement borehole environment. In addition, the response of the rock to excavation and heating will be investigated. The experiment also allows for the development of the technologies needed to demonstrate some of the vault engineering activities proposed in the Canadian nuclear fuel waste disposal concept. These include excavation of large diameter boreholes for waste emplacement and in situ compaction of a bentonite/sand buffer mixture. Although these methodologies developed for the URL have not been optimized for the commercial, full-scale operations needed for a disposal vault, results show that the equipment and methodologies needed for vault operations are a reasonable extrapolation of existing technology.

Micromechanical testing of olivine grain boundaries

2021 ◽  
Author(s):  
Diana Avadanii ◽  
Lars Hansen ◽  
Ed Darnbrough ◽  
Katharina Marquardt ◽  
David Armstrong ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Large Scale ◽  
Boundary Migration ◽  
Small Scale ◽  
High Angle ◽  
In Situ Tests ◽  
Tidal Forces ◽  
In Situ Experiments

<p>The mechanics of olivine deformation play a key role in large-scale, long-term planetary processes, such as the response of the lithosphere to tectonic loading or the response of the solid Earth to tidal forces, and in short-term processes, such as the evolution of roughness on oceanic fault surfaces or postseismic creep within the upper mantle. Many previous studies have emphasized the importance of grain-size effects in the deformation of olivine. However, most of our understanding of the role of grain boundaries in deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples.</p><p>To directly observe and quantify the mechanical properties of olivine grain boundaries, we use high-precision mechanical testing of synthetic forsterite bicrystals with well characterised interfaces. We conduct nanoindentation tests at room temperature on low-angle (13<sup>o</sup> tilt about [100] on (015)) and high-angle (60<sup>o</sup> tilt about [100] on (011)) grain boundaries. We observe that plasticity is easier to initiate if the grain boundary is within the volume tested. This observation agrees with the interpretation that certain grain-boundary configurations can act as sites for initiating microplasticity.</p><p>As part of continuing efforts, we are also conducting in-situ micropillar compression tests at high-temperature (above 600<sup>o</sup> C) within similar bicrystals. In these experiments, the boundary is contained within the micropillar and oriented at 45<sup>o</sup> to the loading direction to promote shear along the boundary. In these in-situ tests, our hypothesis is that the low-angle grain boundary displays a higher viscosity relative to the high-angle interface. Key advantages of performing in-situ experiments are the direct observation of grain-boundary migration or sliding, simplified kinematics of a single boundary segment, and  potentially changes in style of deformation with different grain-boundary character.</p><p>These small deformation volume experiments allow us to qualitatively explore the differences between the crystal interior and regions containing grain boundaries. Overall, the variation in strain and temperature in our small scale experiments allows the fundamental investigation of the response of well characterised forsterite grain boundaries to deformation. </p>

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

2021 ◽  
Vol 144 ◽  
pp. 104582
Author(s):  
D.M. Seyedi ◽  
C. Plúa ◽  
M. Vitel ◽  
G. Armand ◽  
J. Rutqvist ◽  
...  
Keyword(s):  
Full Scale ◽  
Small Scale ◽  
In Situ Experiments

Coupled Thermo-Hydro-Geochemical Models of Engineered Barrier Systems: The Febex Project

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Numerical Models ◽  
Full Scale ◽  
Small Scale ◽  
Model Parameters ◽  
In Situ Test ◽  
Wide Range ◽  
Engineered Barrier

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

Modelling coupled processes in bentonite: recent results from the UK's contribution to the Äspö EBS Task Force

2012 ◽  
Vol 76 (8) ◽  
pp. 3033-3043 ◽  
Author(s):  
D. Holton ◽  
S. Baxter ◽  
A. R. Hoch
Keyword(s):  
Large Scale ◽  
Task Force ◽  
Fractured Rock ◽  
Coupled Processes ◽  
Spent Fuel ◽  
Rock Interaction ◽  
Waste Container ◽  
Buffer Material ◽  
The Uk

AbstractA range of potential concepts for the geological disposal of high level wastes and spent fuel are being studied and considered in the UK. These include concepts that use bentonite as a buffer material around the waste containers. The bentonite will be required to fulfil certain safety functions, the most important being (1) to protect the waste containers from detrimental thermal, hydraulic, mechanical and chemical processes; and (2) to retard the release of radionuclides from any waste container that fails. The bentonite should have a low permeability and a high sorption capacity.These safety functions could be challenged by certain features, events and processes (FEPs) that may occur during the evolution of the disposal system. A consideration of how these FEPs may affect the safety functions can be used to identify and to prioritize the important areas for research on bentonite. We identify these important areas (which include hydration of compacted bentonite, illitization and erosion of bentonite), and describe how they are being investigated in current international research on bentonite.The Äspö EBS Task Force is a collaborative international project designed to carry out research on bentonite. In 2011, the Nuclear Decommissioning Authority Radioactive Waste Management Directorate joined the EBS Task Force partly to benefit from its collective experience. The work of the EBS Task Force is split into two research subareas: (1) the THM subarea, which includes tasks to understand homogenization of bentonite as it resaturates, to investigate the hydraulic interaction between bentonite and fractured rock, and to model in situ experiments; and (2) the THC subarea, which includes tasks to investigate the issue of understanding transport through bentonite, and to model in situ experiments. In particular, the bentonite rock interaction experiment is a large-scale in situ experiment concerned with understanding groundwater exchange across bentonite rock interfaces, with the objective of establishing better understanding of bentonite wetting. In this paper, we describe our work to model the spatial and temporal resaturation of bentonite buffer in a fractured host rock.

ENHANCEMENT OF SPILLED OIL BIODEGRADATION BY NUTRIENTS OF NATURAL ORIGIN

1993 ◽  
Vol 1993 (1) ◽  
pp. 495-501 ◽  
Author(s):  
Anne Basseres ◽  
Patrick Eyraud ◽  
Alain Ladousse ◽  
Bernard Tramier
Keyword(s):  
Oil Spills ◽  
Degradation Kinetics ◽  
Hydrocarbon Degradation ◽  
Hydrocarbon Biodegradation ◽  
Biological Degradation ◽  
In Situ Tests ◽  
Natural Origin ◽  
In Situ Experiments ◽  
Mechanical Aeration

ABSTRACT Ten years ago, Elf Aquitaine began developing the technologies for the acceleration of hydrocarbon biodegradation. The continuation of this work has involved the study of new additives to complement the oleophilic nutrient, INIPOL EAP 22. In particular, it has been shown in both laboratory and in situ tests that hydrocarbon degradation can be accelerated by animal meals, which are natural products. Preliminary laboratory studies carried out under batch conditions, have shown that the use of these products has resulted in considerable growth of the bacteria, coupled with a notable increase in the biological degradation kinetics of the hydrocarbons. These results are comparable with the performance of the nutrient INIPOL EAP 22. In situ experiments undertaken on soils polluted by hydrocarbons have shown that by using animal meals, 50 percent biodegradation was obtained after six weeks and this increased to 80 percent when mechanical aeration was also employed. Under nutrient-free control conditions, 25 percent biodegradation was obtained with no aeration and 35 percent with mechanical aeration. In trials using coastal sandy sediments, the use of these nutrients has resulted in an increase of both the number of hydrocarbon specific bacteria and the hydrocarbon degradation. It can be concluded from these pilot experiments that in the development of bioremediation as an operational tool in the response to accidental oil spills, these nutrients of natural origin represent an interesting advance.

scholarly journals A Fast and Implantation-Free Sample Production Method for Large Scale Electron-Transparent Metallic Samples Destined for MEMS-Based In Situ S/TEM Experiments

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1085
Author(s):  
Matheus A. Tunes ◽  
Cameron R. Quick ◽  
Lukas Stemper ◽  
Diego S. R. Coradini ◽  
Jakob Grasserbauer ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Large Scale ◽  
Microelectromechanical Systems ◽  
Materials Science ◽  
Basic Research ◽  
Production Method ◽  
Chip Experiment ◽  
In Situ Experiments ◽  
Electron Microscopes

Microelectromechanical systems (MEMS) are currently supporting ground-breaking basic research in materials science and metallurgy as they allow in situ experiments on materials at the nanoscale within electron microscopes in a wide variety of different conditions such as extreme materials dynamics under ultrafast heating and quenching rates as well as in complex electro-chemical environments. Electron-transparent sample preparation for MEMS e-chips remains a challenge for this technology as the existing methodologies can introduce contaminants, thus disrupting the experiments and the analysis of results. Herein we introduce a methodology for simple and fast electron-transparent sample preparation for MEMS e-chips without significant contamination. The quality of the samples as well as their performance during a MEMS e-chip experiment in situ within an electron microscope are evaluated during a heat treatment of a crossover AlMgZn(Cu) alloy.

scholarly journals Substantiationofrules ofsimilarityofbreakingloadoftwistedfishinggear

2020 ◽  
Vol 0 (1) ◽  
pp. 38-45
Author(s):  
Alexander Alekseevich Nedostup ◽  
Pavel Nasenkov ◽  
Alexey Olegovich Razhev ◽  
Karina Konovalova ◽  
Sergey Fedorov
Keyword(s):  
Mechanical Properties ◽  
Large Scale ◽  
Large Diameter ◽  
Experimental Studies ◽  
Physical And Mechanical Properties ◽  
Breaking Load ◽  
Full Scale ◽  
Fishing Gear ◽  
Scale Modeling ◽  
Polyamide Fibers

The article focuses on the problem of physical modeling of the physical and mechanical properties of fishing twisted filamentary materials, in particular, the most important one – the breaking load. The problems arise because of conducting full-scale experiments, particularly when the ropes of large diameter are used to build the rope parts of fishing gear. The solution to the problem of determining the breaking load on filamentary parts can be found by using specialized tensile testing machines and modern software, which is an effective tool for predicting the reliability and a resource of a gear part operating in difficult conditions of dynamic and shock loads. However, de-signing of fishing gear must begin with large-scale modeling, which will help to correctly calculate the physical and mechanical properties of the designed object using the well-known parameters of the full-scale material. The similarity rules of breaking load of fishing twisted filamentary gear used for the construction of industrial fishing tools will make it possible to model new elements of these tools without conducting full-scale experiments. At the same time, they will already contain solutions to problems associated with studying the dynamic processes, deformation, fracture, as well as the prediction of reliability and resource of the material. The technique proposed based on determining the scale of similarity of filamentary gear made of polyamide fibers, will help to simu-late various net and rope elements from filaments gear of various sizes and structures, instead of conducting energy-intensive experimental studies on ropes of large diameter.

scholarly journals Substantiation of similitude rules of bending stiffness of twisted fishing gear

2020 ◽  
Vol 0 (1) ◽  
pp. 77-85
Author(s):  
Alexander Alekseevich Nedostup ◽  
Karina Konovalova ◽  
Pavel Nasenkov ◽  
Alexey Olegovich Razhev ◽  
Sergey Fedorov
Keyword(s):  
Physical Modeling ◽  
Large Scale ◽  
Large Diameter ◽  
Physical And Mechanical Properties ◽  
Bending Stiffness ◽  
Full Scale ◽  
Dynamic Processes ◽  
Fishing Gear ◽  
Commercial Fishery ◽  
Engineering Structures

The article considers the problems of physical modeling of twisted filamentary parts of fishing gear and the similitude rules of bending stiffness of filamentary gear parts (FP). The problems are caused firstly by the scope, high costs and complexity of engineering structures in commercial fishery, and thus it was impossible to use them in full-scale testing. Secondly, the lack of systematic experiments prevented from measuring the bending stiffness of synthetic rope parts of fishing gear (SRP). Thus, it becomes necessary to conduct model experiments related to physical modeling of dynamic processes occurring in twisted fishing gear, as well as to carry out a detailed study of the theory of similarity. An attempt to evaluate the bending stiffness of a full-scale object made of polyamide (diameter = 10 mm, the object length and pin diameter were found using large-scale physical characteristics) based on the analysis of experimental data on bending stiffness of synthetic filamentous gear parts made of polyamide with different diameter and length (length = 0.08; 0.10; 0.12; 0.16; 0.20, 0.24 m and diameter = 1.10; 2.0; 3.10; 4.0; 5.0, 6.0 mm) defined on the pins with diameter = 2.0, 10.0 and 30.0 mm. The obtained data will help to prove the correctness of using the theory of dynamic similarity in the course of justification of similarity rules of bending stiffness of the large-diameter cordage and to determine the basic physical and mechanical properties necessary for modeling industrial fishing gear.

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