Particulate Matter and Noise Impact Studies of Waste Rock Dump ...

African Journals Online (AJOL)

Adansi Gold Company Limited identified an economically viable gold deposit at Nkran in the Amansie West District of Ghana. Mining of this deposit requires the disposal of waste rock materials at a proposed waste rock dump near Nkran and Koninase communities. Since particulates and noise emissions from the ...

Radioactive safety analysis and assessment of waste rock pile site in uranium tailings

International Nuclear Information System (INIS)

Liu Changrong; Liu Zehua; Wang Zhiyong; Zhou Xinghuo

2007-01-01

Based on theoretical calculation and in-situ test results, distribution and emissions of radioactive nuclides of uranium tailings impoundment and waste rock pile sites are analyzed in this paper. It is pointed out that 222 Rn is the main nuclide of uranium tailings impoundment and waste rock pile site. Also 222 Rn is the main source term of public dose. 222 Rn concentrations in the atmospheric environment around and individual dose to Rn gradually decrease with increasing distances to uranium tailings impoundment and waste rock pile site. Based on in-situ tests on five uranium tailings impoundment and waste rock pile sites, a decisive method and safety protection distance are presented, which can be used to guide the validation and design of radioactive safety protection in uranium tailings impoundment and waste rock pile sites. (authors)

Effects of bioleaching on the mechanical and chemical properties of waste rocks

Science.gov (United States)

Yin, Sheng-Hua; Wu, Ai-Xiang; Wang, Shao-Yong; Ai, Chun-Ming

2012-01-01

Bioleaching processes cause dramatic changes in the mechanical and chemical properties of waste rocks, and play an important role in metal recovery and dump stability. This study focused on the characteristics of waste rocks subjected to bioleaching. A series of experiments were conducted to investigate the evolution of rock properties during the bioleaching process. Mechanical behaviors of the leached waste rocks, such as failure patterns, normal stress, shear strength, and cohesion were determined through mechanical tests. The results of SEM imaging show considerable differences in the surface morphology of leached rocks located at different parts of the dump. The mineralogical content of the leached rocks reflects the extent of dissolution and precipitation during bioleaching. The dump porosity and rock size change under the effect of dissolution, precipitation, and clay transportation. The particle size of the leached rocks decreased due to the loss of rock integrity and the conversion of dry precipitation into fine particles.

Hydrological evaluation of five sedimentary rocks for high-level waste disposal

International Nuclear Information System (INIS)

Lomenick, T.F.; Kanehiro, B.Y.

1986-01-01

Utilizing performance criteria that are based upon siting guidelines issued by DOE for postclosure as well as preclosure conditions, a preliminary hydrologic evaluation and ranking is being conducted to determine the suitability of five sedimentary rocks as potential host rocks for a high-level radioactive waste repository. Based upon both quantitative and qualitative considerations, the hydrological ranking of the rocks in order of their potential as a host rock for the disposal of radioactive wastes would be shale, anhydrock, sandstone, chalk, and carbonates, with the first three rocks being significantly better than the remaining two types

Rock mechanics in the National Waste Terminal Storage Program

International Nuclear Information System (INIS)

Monsees, J.E.; Wigley, M.R.

1982-01-01

The overall objective of the rock mechanics program of the Office of Nuclear Waste Isolation is to predict the response of a rock mass hosting a waste repository during its construction, operation, and postoperational phases. The operational phase is expected to be 50 to 100 yr; the postoperational phase will last until the repository no longer poses any potential hazard to the biosphere, a period that may last several thousand years. The rock mechanics program is concerned with near-field effects on mine stability, as well as far-field effects relative to the overall integrity of the geologic waste isolation system. To accomplish these objectives, the rock mechanics program has established interactive studies in numerical simulation, laboratory testing, and field testing. The laboratory and field investigations provide input to the numerical simulations and give an opportunity for verification and validation of the predictive capabilities of the computer codes. Ultimately the computer codes will be used to predict the response of the geologic system to the development of a repository. 3 references, 5 figures

Modeling acid mine drainage in waste rock dumps

Energy Technology Data Exchange (ETDEWEB)

Lefebvre, R. [INRS, Quebec (Canada)

1995-03-01

Acid mine drainage (AMD) results from the oxidation of sulfides present in mine wastes. The acidity generated by these reactions creates conditions under which metals can be leached and represent a threat for surface and ground waters. Even though leachate collection and neutralization are used to treat the problem, the industry is looking for methods to predict and prevent the generation of AMD at new sites and control methods for sites already producing AMD. Waste rock dumps are generally very large accumulations of barren rocks extracted from open pits to access ore bodies. These rocks contain sulfides, most commonly pyrite, and often generate AMD at rates much higher than in mine tailings which are fine grained by-products of milling operations. Numerous coupled physical processes are involved in AMD production in waste rocks. Sulfide oxidation reactions are strongly exothermic and temperatures beyond 70{degrees}C have been measured in some dumps. That heat is transfered by conduction and fluid advection. Dumps have thick partly saturated zones through which gases flow under thermal gradients and water infiltrates. Oxygen is required by the oxidation reactions and is supplied by diffusion and advection. The reaction products are carried in solution in very concentrated leachates. Numerical modeling of AMD aims to (1) provide a better understanding of the physical processes involved in AMD, (2) allow the integration of available waste rock characterization data, (3) indicate new data or studies which are required to fill the gaps in our quantitative understanding of AMD processes, and (4) supply a tool for the prediction of AMD production, taking into account the impact of control methods. These objectives can only be met through sustained research efforts. This study is part of a wider research effort which as been on-going at La Mine Doyon since 1991.

Thermal aspects of radioactive waste disposal in hard rock

International Nuclear Information System (INIS)

Beale, H.; Bourke, P.J.; Hodgkinson, D.P.

1980-01-01

Buried heat emitting radioactive waste will appreciably raise the temperature of the surrounding rock over distances of several hundred metres for many centuries. This paper describes continuing research at Harwell aimed at understanding how this heating affects the design of hard rock depositories for the waste. It also considers how water-borne leakage of radionuclides from a depository to the surface might be increased by thermal convection currents through the rock mass and by thermally induced changes in its permeability and porosity. A conceptual design for a three-dimensional depository with an array of vitrified waste blocks placed in vertical boreholes is described. The maximum permissible power outputs of individual blocks and the minimum permissible separations between blocks to limit the local and bulk average rock temperatures will be determined by heat transfer through the rock and are reviewed. Interim results of a field heating experiment to study transient heat transfer through granite are discussed subsequently. Field experiments are now being started to measure the fracture permeability and porosity over large distances in virgin granite and to investigate their variation on heating and cooling the rock. Theoretical estimates of the temperatures, thermal stresses and thermal convection currents around a depository are next presented. The implications for water-borne leakage are that the induced stresses could change the fracture permeability and porosity, and thermal convection could cause substantial water movement vertically towards the surface. Finally some conclusions from the work are presented. (author)

Uranium migration and retention during weathering of a granitic waste rock pile

International Nuclear Information System (INIS)

Boekhout, F.; Gérard, M.; Kanzari, A.; Michel, A.; Déjeant, A.; Galoisy, L.; Calas, G.; Descostes, M.

2015-01-01

Highlights: • We investigate the environmental impact of the granitic waste rock piles. • The majority of the waste rocks in the pile is barren- or overburden rock. • The main neo-formed U-bearing phases are (Ca) and (Cu) uranyl phosphates. • Under circum-neutral pH conditions they do not pose an environment threat. - Abstract: This study investigates the post-mining evolution of S-type granitic waste rocks around a former uranium mine, Vieilles Sagnes (Haute Vienne, NW Massif Central, France). This mine was operated between 1957 and 1965 in the La Crouzille former world-class uranium mining district and is representative of intra-granitic vein-type deposits. 50 years after mine closure and the construction and subsequent re-vegetation of the granitic waste rock pile, we evaluate the environmental evolution of the rock pile, including rock alteration, neo-formation of U-bearing phases during weathering, and U migration. Vertical trenches have been excavated through the rock pile down to an underlying paleo-soil, allowing the investigation of the vertical differentiation of the rock pile and its influence on water pathways, weathering processes and U migration and retention. Arenization dominantly drives liberation of U, by dissolution of uraninite inclusions in the most alterable granitic minerals (i.e. K-feldspar and biotite). Retention of U in the matrix at the base of the waste rock pile, and in the underlying paleo-soil most likely occurs by precipitation of (nano-) uranyl phosphates or a combination of co-precipitation and adsorption reactions of U onto Fe (oxy)hydroxides and/or clay minerals. Even though U-migration was observed, U is retained in stable secondary mineral phases, provided the current conditions will not be modified

Rock mass modification around a nuclear waste repository in welded tuff

International Nuclear Information System (INIS)

Mack, M.G.; Brandshaug, T.; Brady, B.H.

1989-08-01

This report presents the results of numerical analyses to estimate the extent of rock mass modification resulting from the presence of a High Level Waste (HLW) repository. Changes in rock mass considered are stresses and joint deformations resulting from disposal room excavation and thermal efffects induced by the heat generated by nuclear waste. rock properties and site conditions are taken from the Site Characterization Plan Conceptual Design Report for the potential repository site at Yucca Mountain, Nevada. Analyses were conducted using boundary element and distinct element methods. Room-scale models and repository-scale models were investigated for up to 500 years after waste emplacement. Results of room-scale analyses based on the thermoelastic boundary element model indicate that a zone of modified rock develops around the disposal rooms for both vertical and horizontal waste emplacement. This zone is estimated to extend a distance of roughly two room diameters from the room surface. Results from the repository-scale model, which are based on the thermoelastic boundary element model and the distinct element model, indicate a zone with modified rock mass properties starting approximately 100 m above and below the repository, with a thickness of approximately 200 m above and 150 m below the repository. Slip-prone subhorizontal features are shown to have a substantial effect on rock mass response. The estimates of rock mass modification reflect uncertainties and simplifying assumptions in the models. 32 refs., 57 figs., 1 tab

Selection of the host rock for high level radioactive waste repository in China

International Nuclear Information System (INIS)

Jin Yuanxin; Wang Wenguang; Chen Zhangru

2001-01-01

The authors has briefly introduced the experiences of the host rock selection and the host rock types in other countries for high level radioactive waste repository. The potential host rocks in China are investigated. They include granite, tuff, clay, basalt, salt, and loess. The report has expounded the distributions, scale, thickness, mineral and chemical composition, construction, petrogenesis and the ages of the rock. The possibility of these rocks as the host rock has been studied. The six pieces of distribution map of potential rocks have been made up. Through the synthetical study, it is considered that granite as the host rock of high level radioactive waste repository is possible

A model of pyritic oxidation in waste rock dumps

International Nuclear Information System (INIS)

Davis, G.B.; Ritchie, A.I.M.

1983-01-01

The oxidation of pyrite can lead to high acid levels and high concentrations of trace metals in the water that runs off and percolates through pyritic material. This is the situation at the abandoned uranium mine at Rum Jungle in the Northern Territory of Australia, where pyritic oxidation in the waste rock dumps resulting from open cut mining of the uranium orebody has led to pollution of the nearby East Branch of the Finniss River, with trace metals such as copper, manganese and zinc. Mathematical equations are formulated which describe a model of pyritic oxidation within a waste rock dump, where it is assumed that oxygen transport is the rate limiting step in the oxidation process and that oxygen is transported by gaseous diffusion through the pore space of the dump, followed by diffusion into oxidation sites within the particles that comprise the dump. The equations have been solved numerically assuming values for such parameters as porosity, sulphur density and oxygen diffusion coefficients which are applicable to the waste rock dumps at Rum Jungle. An approximate solution to the equations is also presented. Calculations of the heat source distribution and the total SO 4 production rate are presented for both single size particles and for a range of particle sizes in the dump. The usefulness of the approximate solution, and of calculations based on single size particles in the dump in assessing the effectiveness of strategies to reduce pollution from such waste rock dumps are discussed

Lined rock caverns for the storage of hazardous waste

International Nuclear Information System (INIS)

Semprich, S.; Speidel, S.R.; Schneider, H.J.

1987-01-01

For reasons of environmental protection the storage of hazardous waste in unlined rock caverns is possible to a very limited extent only. Therefore, the authors have recently developed technologies for the lining and sealing of rock caverns. In the process, sealing systems of synthetic materials or metals have proved suitable. Synthetic materials can be used in the form of either sheets or coatings with various materials such as epoxy resins, polyethylenes etc. being used. Metal sealings consist of thin sheets or foils which are either welded or bonded. In either case, the structural design must provide for a leakage control possibility. The article describes the design principles, the structural and operational aspects as well as the control measures with regard to the planning and execution of lined rock caverns for the storage of hazardous waste

Mathematical simulation of a waste rock heap

International Nuclear Information System (INIS)

Scharer, J.M.; Pettit, C.M.; Chambers, D.B.; Kwong, E.C.

1994-01-01

A computer model has been developed to simulate the generation of acidic drainage in waste rock piles. The model considers the kinetic rates of biological and chemical oxidation of sulfide minerals (pyrite, pyrrhotite) present as fines and rock particles, as well as chemical processes such as dissolution (kinetic or equilibrium controlled), complexation (from equilibrium and stoichiometry of several complexes), and precipitation (formation of complexes and secondary minerals). Through mass balance equations and solubility constraints (e.g., pH, phase equilibria) the model keeps track of the movement of chemical species through the waste pile and provides estimates of the quality of seepage (pH, sulfate, iron, acidity, etc.) leaving the heap. The model has been expanded to include the dissolution (thermodynamic and sorption equilibrium), adsorption and coprecipitation of uranium and radium. The model was applied to simulate waste rock heaps in British Columbia, Canada and in Thueringia, Germany. To improve the accuracy and confidence of long-term predictions of seepage quality, the entire history of the heaps was simulated. Cumulative acidity loads and water treatment considerations were used as a basis for evaluation of various decommissioning alternatives. Simulation of the technical leaching history of a heap in Germany showed it will generate contaminated leachate requiring treatment for acidity and radioactivity for several hundred years; cover installation was shown to provide a significant reduction of potential burdens, although chemical treatment would still be required beyond 100 years

Mixing-controlled uncertainty in long-term predictions of acid rock drainage from heterogeneous waste-rock piles

Science.gov (United States)

Pedretti, D.; Beckie, R. D.; Mayer, K. U.

2015-12-01

The chemistry of drainage from waste-rock piles at mine sites is difficult to predict because of a number of uncertainties including heterogeneous reactive mineral content, distribution of minerals, weathering rates and physical flow properties. In this presentation, we examine the effects of mixing on drainage chemistry over timescales of 100s of years. We use a 1-D streamtube conceptualization of flow in waste rocks and multicomponent reactive transport modeling. We simplify the reactive system to consist of acid-producing sulfide minerals and acid-neutralizing carbonate minerals and secondary sulfate and iron oxide minerals. We create multiple realizations of waste-rock piles with distinct distributions of reactive minerals along each flow path and examine the uncertainty of drainage geochemistry through time. The limited mixing of streamtubes that is characteristic of the vertical unsaturated flow in many waste-rock piles, allows individual flowpaths to sustain acid or neutral conditions to the base of the pile, where the streamtubes mix. Consequently, mixing and the acidity/alkalinity balance of the streamtube waters, and not the overall acid- and base-producing mineral contents, control the instantaneous discharge chemistry. Our results show that the limited mixing implied by preferential flow and the heterogeneous distribution of mineral contents lead to large uncertainty in drainage chemistry over short and medium time scales. However, over longer timescales when one of either the acid-producing or neutralizing primary phases is depleted, the drainage chemistry becomes less controlled by mixing and in turn less uncertain. A correct understanding of the temporal variability of uncertainty is key to make informed long-term decisions in mining settings regarding the management of waste material.

Rock support for nuclear waste repositories

International Nuclear Information System (INIS)

Abramson, L.W.; Schmidt, B.

1984-01-01

The design of rock support for underground nuclear waste repositories requires consideration of special construction and operation requirements, and of the adverse environmental conditions in which some of the support is placed. While repository layouts resemble mines, design, construction and operation are subject to quality assurance and public scrutiny similar to what is experienced for nuclear power plants. Exploration, design, construction and operation go through phases of review and licensing by government agencies as repositories evolve. This paper discusses (1) the various stages of repository development; (2) the environment that supports must be designed for; (3) the environmental effects on support materials; and (4) alternative types of repository rock support

Appraisal of hard rock for potential underground repositories of radioactive wastes

International Nuclear Information System (INIS)

Cook, N.G.W.

1977-10-01

The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

A Rock Mechanics and Coupled Hydro mechanical Analysis of Geological Repository of High Level Nuclear Waste in Fractured Rocks

International Nuclear Information System (INIS)

Min, Kibok

2011-01-01

This paper introduces a few case studies on fractured hard rock based on geological data from Sweden, Korea is one of a few countries where crystalline rock is the most promising rock formation as a candidate site of geological repository of high level nuclear waste. Despite the progress made in the area of rock mechanics and coupled hydro mechanics, extensive site specific study on multiple candidate sites is essential in order to choose the optimal site. For many countries concerned about the safe isolation of nuclear wastes from the biosphere, disposal in a deep geological formation is considered an attractive option. In geological repository, thermal loading continuously disturbs the repository system in addition to disturbances a recent development in rock mechanics and coupled hydro mechanical study using DFN(Discrete Fracture Network) - DEM(Discrete Element Method) approach mainly applied in hard, crystalline rock containing numerous fracture which are main sources of deformation and groundwater flow

Rock-welding materials for deep borehole nuclear waste disposal.

Energy Technology Data Exchange (ETDEWEB)

Yang, Pin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Wang, Yifeng [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Rodriguez, Mark A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brady, Patrick Vane [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Swift, Peter N. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-11-01

The concept of deep borehole nuclear waste disposal has recently been proposed. Effective sealing of a borehole after waste emplacement is generally required. In a high temperature disposal mode, the sealing function will be fulfilled by melting the ambient granitic rock with waste decay heat or an external heating source, creating a melt that will encapsulate waste containers or plug a portion of the borehole above a stack of the containers. However, there are certain drawbacks associated with natural materials, such as high melting temperatures, slow crystallization kinetics, the resulting sealing materials generally being porous with low mechanical strength, insufficient adhesion to waste container surface, and lack of flexibility for engineering controls. Here we show that natural granitic materials can be purposefully engineered through chemical modifications to enhance the sealing capability of the materials for deep borehole disposal. This work systematically explores the effect of chemical modification and crystallinity (amorphous vs. crystalline) on the melting and crystallization processes of a granitic rock system. A number of engineered granitic materials have been obtained that have decreased melting points, enhanced viscous densification, and accelerated recrystallization rates without compromising the mechanical integrity of the materials.

Rock mechanics in the disposal of radioactive wastes by hydraulic fracturing

Energy Technology Data Exchange (ETDEWEB)

McClain, W C

1968-01-01

The ultimate capacity of a hydraulic-fracturing waste disposal facility is governed primarily by the integrity of the rocks overlying the injected wastes. The objective of this study is to analyze theoretically the stresses and strains generated by the injected wastes in an effort to understand the behavior of the system sufficiently well that the failure mechanism can be predicted and the capacity of the injection well estimated. The surface uplifts at Oak Ridge National Laboratory's fracturing site were compared with theoretical curves obtained by assuming the uplifts to be inversely analogous to the subsidence which occurs over mining excavations. This analysis, based on assumptions of homogeneity, isotropy, and linear elasticity, provided considerable insight into the mechanics of the process. The most probable mechanism of failure of the rock appears to be by the formation of a vertical instead of a horizontal fracture. Fracture orientation is controlled primarily by the orientation of the principal stress field in the rock. Each successive waste injection slightly modifies this stress field toward a condition more favorable to the formation of a vertical fracture. (16 refs.)

The formation of technic soil in a revegetated uranium ore waste rock pile (Limousin, France)

Science.gov (United States)

Boekhout, Flora; Gérard, Martine; Kanzari, Aisha; Calas, Georges; Descostes, Michael

2014-05-01

Mining took place in France between 1945 and 2001 during which time ~210 different sites were exploited and/or explored. A total of 76 Kt of uranium was produced, 52 Mt of ore was extracted, but also 200 Mt of waste rocks was produced, the majority of which, with uranium levels corresponding to the natural environment. So far, the processes of arenisation and technic soil formation in waste rock piles are not well understood but have important implications for understanding the environmental impact and long-term speciation of uranium. Understanding weathering processes in waste rock piles is essential to determine their environmental impact. The main objectives of this work are to assess 1) the micromorphological features and neo-formed U-bearing phases related to weathering and 2) the processes behind arenisation of the rock pile. The site that was chosen is the Vieilles Sagnes waste rock pile in Fanay (Massif Central France) that represents more or less hydrothermally altered granitic rocks that have been exposed to weathering since the construction of the waste rock pile approximately 50 years ago. Two trenches were excavated to investigate the vertical differentiation of the rock pile. This site serves as a key location for studying weathering processes of waste rock piles, as it has not been reworked after initial construction and has therefore preserved information on the original mineralogy of the waste rock pile enabling us to access post emplacement weathering processes. The site is currently overgrown by moss, meter high ferns and small trees. At present day the rock pile material can be described as hydrothermally altered rocks and rock fragments within a fine-grained silty clay matrix exposed to surface conditions and weathering. A sandy "paleo" technic soil underlies the waste rock pile and functions as a natural liner by adsorption of uranium on clay minerals. Post-mining weathering of rock-pile material is superimposed on pre-mining hydrothermal and

Transient diffusion from a waste solid into fractured porous rock

International Nuclear Information System (INIS)

Ahn, J.; Chambre, P.L.; Pigford, T.H.

1988-01-01

Previous analytical studies of the advective transport of dissolved contaminants through fractured rock have emphasized the effect of molecular diffusion in the rock matrix in affecting the space-time-dependent concentration of the contaminant as it moves along the fracture. Matrix diffusion only in the direction normal to the fracture surface was assumed. Contaminant sources were constant-concentration surfaces of width equal to the fracture aperture and of finite or infinite extent in the transverse direction. Such studies illustrate the far-field transport features of fractured media. To predict the time-dependent mass transfer from a long waste cylinder surrounded by porous rock and intersected by a fracture, the present study includes diffusion from the waste surface directly into porous rock, as well as the more realistic geometry. Here the authors present numerical results from Chambre's analytical solution for the time-dependent mass transfer from the cylinder for the low-flow conditions wherein near-field mass transfer is expected to be controlled by molecular diffusion

Temperature loading and rocks mechanics at final storage of radioactive waste

International Nuclear Information System (INIS)

Leijon, B.; Stephansson, O.

1979-01-01

This report describes the rock mechanical effects - in the far field - from the thermal loading at a final storage of radioactive waste in crystalline rocks. The stress distribution of a two-storey storage is described in more details. The temperature rise in a final storage of radiactive waste will create thermal stresses which may cause a failure of the rock mass, and thereby an increase of its permeability. However, the state of stress in the Earth's crust is able to neutralize the thermal stresses. By this analysis we have been able to demonstrate that the thermal stresses due to heat conduction from the final storage are compensated by the state of stress in the upper part of the crust. The absolute stress, which is the superposition of thermal stress and virgin rock stress, is in all cases found to be below the limit of failure due to frictional resistance between surfaces of constituent blocks in the rock mass. Failure by sliding friction is the most conservative failure criterion for a rock mass. (author)

Appraisal of hard rock for potential underground repositories of radioactive wastes. LBL-7004

International Nuclear Information System (INIS)

Cook, N.G.W.

1978-01-01

Underground burial of radioactive wastes in hard rock may be an effective and safe means of isolating them from the environment and from man. The mechanical safety and stability of such an underground repository depends largely on the virgin state of stress in the rock, groundwater pressures, the strengths of the rocks, heating by the decay of the radioactive wastes, and the layout of the excavations and the disposition of waste cannisters within them. A large body of pertinent data exists in the literature, and each of these factors has been analyzed in the light of this information. The results indicate that there are no fundamental geological nor mechanical reasons why repositories capable of storing radioactive wastes should not be excavated at suitable sites in hard rock. However, specific tests to determine the mechanical and thermal properties of the rocks at a site would be needed to provide the data for the engineering design of a repository. Also, little experience exists of the effects on underground excavations of thermal loads, so that this aspect requires theoretical study and experimental validation. The depths of these potential repositories would lie in the range from 0.5 km to 2.0 km below surface, depending upon the strength of the rock. Virgin states of stress have been measured at such depths which would retard the ingress of groundwater and obviate the incidence of faulting. A typical repository comprising three horizons each with a total area of 5 km 2 would have the capacity to store wastes with thermal output of 240 MW

Rock stresses associated with burial of nuclear waste

International Nuclear Information System (INIS)

Voight, B.

1977-01-01

Rock stress changes related to long-term deep storage of nuclear waste involve thermoelastic and pore fluid pressure changes associated with excavation and heating. Computer models are being examined to assess the question of thermally-induced fracturing in storage rock surrounding radioactive waste containers. Stresses are evaluated in three dimensions, employing elastic-plastic finite element codes. Potential failure conditions are expressed in terms of ''effective stresses,'' and force and thermal fields are incremented to produce an appropriate load path. In general, heating in vicinity of waste containers produces a zone of high compression bonded by a zone of circumferential and axial tension. (At this conference an analogous case of thermal stresses was documented and illustrated for larger-scale temperature domains associated with geothermal areas in Iceland.) Fractures are possible in radial directions as well as perpendicular to the axis of the cylindrical heat source. In addition, the mechanical effect of a vapor pulse will be explored by a two-phase numerical fluid transport model used in conjunction with mechanical finite element models. This portion of the work, being conducted jointly with C. R. Faust and J. W. Mercer of the US Geological Survey, should provide a preliminary appreciation of the possible effect of phase changes on fracturing of burial sites. Preliminary work suggests the possibility of establishing design criteria (e.g., design burial depth, depth of canister below storage vault) in order to minimize problems of potential rock fracture

Thermal characteristics of rocks for high-level waste repository

International Nuclear Information System (INIS)

Shimooka, Kenji; Ishizaki, Kanjiro; Okamoto, Masamichi; Kumata, Masahiro; Araki, Kunio; Amano, Hiroshi

1980-12-01

Heat released by the radioactive decay of high-level waste in an underground repository causes a long term thermal disturbance in the surrounding rock mass. Several rocks constituting geological formations in Japan were gathered and specific heat, thermal conductivity, thermal expansion coefficient and compressive strength were measured. Thermal analysis and chemical analysis were also carried out. It was found that volcanic rocks, i.e. Andesite and Basalt had the most favorable thermal characteristics up to around 1000 0 C and plutonic rock, i.e. Granite had also favorable characteristics under 573 0 C, transition temperature of quartz. Other igneous rocks, i.e. Rhyolite and Propylite had a problem of decomposition at around 500 0 C. Sedimentary rocks, i.e. Zeolite, Tuff, Sandstone and Diatomite were less favorable because of their decomposition, low thermal conductivity and large thermal expansion coefficient. (author)

Concept for Underground Disposal of Nuclear Waste

Science.gov (United States)

Bowyer, J. M.

1987-01-01

Packaged waste placed in empty oil-shale mines. Concept for disposal of nuclear waste economically synergistic with earlier proposal concerning backfilling of oil-shale mines. New disposal concept superior to earlier schemes for disposal in hard-rock and salt mines because less uncertainty about ability of oil-shale mine to contain waste safely for millenium.

Symmetric Rock Fall on Waste Package

International Nuclear Information System (INIS)

Sreten Mastilovic

2001-01-01

The objective of this calculation is to determine the structural response of the Naval SNF (spent nuclear fuel) Waste Package (WP) and the emplacement pallet (EP) subjected to the rock fall DBE (design basis event) dynamic loads. The scope of this calculation is limited to reporting the calculation results in terms of stress intensities and residual stresses in the WP, and stress intensities and maximum permanent downward displacements of the EP-lifting surface. The information provided by the sketches (Attachment I) is that of the potential design of the type of WP and EP considered in this calculation, and all obtained results are valid for those designs only. This calculation is associated with the waste package design and is performed by the Waste Package Design Section in accordance with Reference 24. AP-3.124, ''Calculations'', is used to perform the calculation and develop the document

Summary review of rock mechanics workshop on radioactive waste disposal

International Nuclear Information System (INIS)

Carter, N.L.; Goodman, R.E.; Merrill, R.H.

1977-01-01

Presentations, critiques and recommendations for the disposal of commercial radioactive waste based upon an analysis of the information presented at the Rock Mechanics Review/Workshop, Denver, Colorado, December 16-17, 1976 are summarized. The workshop, comprised of both formal and informal sessions, with about 50 participants, was hosted by RE/SPEC Inc. and Dr. Paul F. Gnirk, President and was sponsored by the Office of Waste Isolation (OWI), led by Dr. William C. McClain. The panel of reviewers, responsible for this report, consisted of Neville L. Carter, Richard E. Goodman, and Robert H. Merrill. These panel members were selected not only on the basis of their experience in various aspects of Rock Mechanics and Mining Engineering but also because they have had no previous active participation in problems concerning disposal of radioactive waste. By way of a general comment, the review panel was very favorably impressed with the Rock Mechanics research efforts, supported by OWI, on this problem and with the level of technical competence of those carrying out the research. Despite the rather preliminary nature of the results presented and the youth of the program itself, it is clear that the essential ingredients for a successful program are at hand, especially as regards disposal in natural salt formations. These include laboratory studies of appropriate rock deformation, numerical analyses of thermal and mechanical stresses around openings, and in situ field tests. We shall comment on each of these three major areas in turn. We shall then offer recommendations for their improvement, and, finally, we shall make more general recommendations for future considerations of the OWI radioactive waste disposal program

The geochemistry of high-level waste disposal in granitic rocks

International Nuclear Information System (INIS)

Chapman, N.A.; Sargent, F.P.

1984-01-01

Under the auspices of the cooperative agreement between Euratom and Atomic Energy of Canada Ltd about radioactive waste management and disposal, a joint workshop was held on the topic of the geochemistry of high-level waste disposal in granitic rocks. The report covers (1) waste form leaching, (2) thermodynamics, (3) geochemical models, (4) the role of colloids, (5) sorption phenomena, (6) the linking of flow and geochemical models, (7) microbial activity

Modelling temperature-dependent heat production over decades in High Arctic coal waste rock piles

DEFF Research Database (Denmark)

Hollesen, Jørgen; Elberling, Bo; Jansson, P.E.

2011-01-01

Subsurface heat production from oxidation of pyrite is an important process that may increase subsurface temperatures within coal waste rock piles and increase the release of acid mine drainage, AMD. Waste rock piles in the Arctic are especially vulnerable to changes in subsurface temperatures...... such as heat production from coal oxidation may be equally important....... as the release of AMD normally is limited by permafrost. Here we show that temperatures within a 20 year old heat-producing waste rock pile in Svalbard (78°N) can be modelled by the one-dimensional heat and water flow model (CoupModel) with a new temperature-dependent heat-production module that includes both...

Molybdenum and zinc stable isotope variation in mining waste rock drainage and waste rock at the Antamina mine, Peru

Energy Technology Data Exchange (ETDEWEB)

Skierszkan, E.K., E-mail: eskiersz@eos.ubc.ca [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Mayer, K.U. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Weis, D. [Pacific Centre for Isotopic and Geochemical Research (PCIGR), Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada); Beckie, R.D. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2020-2207 Main Mall, Vancouver V6T 1Z4 (Canada)

2016-04-15

The stable isotope composition of molybdenum (Mo) and zinc (Zn) in mine wastes at the Antamina Copper–Zn–Mo mine, Peru, was characterized to investigate whether isotopic variation of these elements indicated metal attenuation processes in mine drainage. Waste rock and ore minerals were analyzed to identify the isotopic composition of Mo and Zn sources, namely molybdenites (MoS{sub 2}) and sphalerites (ZnS). Molybdenum and Zn stable isotope ratios are reported relative to the NIST-SRM-3134 and PCIGR-1 Zn standards, respectively. δ{sup 98}Mo among molybdenites ranged from − 0.6 to + 0.6‰ (n = 9) while sphalerites showed no δ{sup 66}Zn variations (0.11 ± 0.01‰, 2 SD, n = 5). Mine drainage samples from field waste rock weathering experiments were also analyzed to examine the extent of isotopic variability in the dissolved phase. Variations spanned 2.2‰ in δ{sup 98}Mo (− 0.1 to + 2.1‰) and 0.7‰ in δ{sup 66}Zn (− 0.4 to + 0.3‰) in mine drainage over a wide pH range (pH 2.2–8.6). Lighter δ{sup 66}Zn signatures were observed in alkaline pH conditions, which was consistent with Zn adsorption and/or hydrozincite (Zn{sub 5}(OH){sub 6}(CO{sub 3}){sub 2}) formation. However, in acidic mine drainage Zn isotopic compositions reflected the value of sphalerites. In addition, molybdenum isotope compositions in mine drainage were shifted towards heavier values (0.89 ± 1.25‰, 2 SD, n = 16), with some overlap, in comparison to molybdenites and waste rock (0.13 ± 0.82‰, 2 SD, n = 9). The cause of heavy Mo isotopic signatures in mine drainage was more difficult to resolve due to isotopic heterogeneity among ore minerals and a variety of possible overlapping processes including dissolution, adsorption and secondary mineral precipitation. This study shows that variation in metal isotope ratios are promising indicators of metal attenuation. Future characterization of isotopic fractionation associated to key environmental reactions will improve the power

Molybdenum and zinc stable isotope variation in mining waste rock drainage and waste rock at the Antamina mine, Peru

International Nuclear Information System (INIS)

Skierszkan, E.K.; Mayer, K.U.; Weis, D.; Beckie, R.D.

2016-01-01

The stable isotope composition of molybdenum (Mo) and zinc (Zn) in mine wastes at the Antamina Copper–Zn–Mo mine, Peru, was characterized to investigate whether isotopic variation of these elements indicated metal attenuation processes in mine drainage. Waste rock and ore minerals were analyzed to identify the isotopic composition of Mo and Zn sources, namely molybdenites (MoS_2) and sphalerites (ZnS). Molybdenum and Zn stable isotope ratios are reported relative to the NIST-SRM-3134 and PCIGR-1 Zn standards, respectively. δ"9"8Mo among molybdenites ranged from − 0.6 to + 0.6‰ (n = 9) while sphalerites showed no δ"6"6Zn variations (0.11 ± 0.01‰, 2 SD, n = 5). Mine drainage samples from field waste rock weathering experiments were also analyzed to examine the extent of isotopic variability in the dissolved phase. Variations spanned 2.2‰ in δ"9"8Mo (− 0.1 to + 2.1‰) and 0.7‰ in δ"6"6Zn (− 0.4 to + 0.3‰) in mine drainage over a wide pH range (pH 2.2–8.6). Lighter δ"6"6Zn signatures were observed in alkaline pH conditions, which was consistent with Zn adsorption and/or hydrozincite (Zn_5(OH)_6(CO_3)_2) formation. However, in acidic mine drainage Zn isotopic compositions reflected the value of sphalerites. In addition, molybdenum isotope compositions in mine drainage were shifted towards heavier values (0.89 ± 1.25‰, 2 SD, n = 16), with some overlap, in comparison to molybdenites and waste rock (0.13 ± 0.82‰, 2 SD, n = 9). The cause of heavy Mo isotopic signatures in mine drainage was more difficult to resolve due to isotopic heterogeneity among ore minerals and a variety of possible overlapping processes including dissolution, adsorption and secondary mineral precipitation. This study shows that variation in metal isotope ratios are promising indicators of metal attenuation. Future characterization of isotopic fractionation associated to key environmental reactions will improve the power of Mo and Zn isotope ratios to track the fate

SUITABILITY ANALYSIS OF WASTE ROCK APPLICATION IN HYDRIC RECLAMATION IN THE NATURAL WATER-BEARING SUBSIDENCE TROUGHS IN KARVINSKO, CZECH REPUBLIC

Directory of Open Access Journals (Sweden)

Eva Pertile

2008-12-01

Full Text Available The paper deals with a suitability analysis of waste rock application in hydric reclamation on the basis of studying its impact on water quality in the natural water-bearing subsidence troughs. The evaluation was carried out in sixteen localities where waste rock had been used in the past for the purposes of bank system improvement. Within the evaluation of waste rock impact on the hydrochemical character of water in the subsidence troughs the values of geochemical background were identified. In order to compare the impact of waste rock on the quality of water, changes in the hydrochemical parameters were monitored in the localities without waste rock banking, with partial (maximum ½ circumference and complete waste rock banking.

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 7. Baseline rock properties-basalt

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM-36/7 Baseline Rock Properties--Basalt, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report contains an evaluation of the results of a literature survey to define the rock mass properties of a generic basalt, which could be considered as a geological medium for storing radioactive waste. The general formation and structure of basaltic rocks is described. This is followed by specific descriptions and rock property data for the Dresser Basalt, the Amchitka Island Basalt, the Nevada Test Site Basalt and the Columbia River Group Basalt. Engineering judgment has been used to derive the rock mass properties of a typical basalt from the relevant intact rock property data and the geological information pertaining to structural defects, such as joints and faults

High-level radioactive waste isolation by incorporation in silicate rock

International Nuclear Information System (INIS)

Schwartz, L.L.; Cohen, J.J.; Lewis, A.E.; Braun, R.L.

1978-01-01

A number of technical possibilities for isolating high-level radioactive materials have been theoretically investigated at various times and places. Isolating such wastes deep underground to ensure long term removal from the biosphere is one such possibility. The present concept involves as a first step creating the necessary void space at considerable depth, say 2 to 5 km, in a very-low-permeability silicate medium such as shale. Waste in dry, calcined or vitrified form is then lowered into the void space, and the access hole or shaft sealed. Energy released by the radioactive decay raises the temperature to a point where the surrounding rock begins to melt. The waste is then dissolved in it. The extent of this melt region grows until the heat generated is balanced by conduction away from the molten zone. Resolidification then begins, and ends when the radioactive decay has progressed to the point that the temperature falls below the melting point of the rock-waste solution. Calculations are presented showing the growth and resolidification process. A nuclear explosion is one way of creating the void space. (author)

Surrounding rock stress analysis of underground high level waste repository

International Nuclear Information System (INIS)

Liu Wengang; Wang Ju; Wang Guangdi

2006-01-01

During decay of nuclear waste, enormous energy was released, which results in temperature change of surrounding rock of depository. Thermal stress was produced because thermal expansion of rock was controlled. Internal structure of surrounding rock was damaged and strength of rock was weakened. So, variation of stress was a dynamic process with the variation of temperature. BeiShan region of Gansu province was determined to be the depository field in the future, it is essential to make research on granite in this region. In the process of experiment, basic physical parameters of granite were analyzed preliminary with MTS. Long range temperature and stress filed was simulated considering the damage effect of surrounding rock, and rules of temperature and stress was achieved. (authors)

Support to other nuclear waste disposal programmes considering clay as a potential host rock

International Nuclear Information System (INIS)

Volckaert, G.

2009-01-01

SCK-CEN started to study the Boom Clay as potential host rock for nuclear waste disposal in 1974. Since then, SCK-CEN has been involved in other international projects studying clay as potential host rock in order to get a broader support for disposal in clay and to acquire broader insight in clay behaviour. Besides Belgium, France and Switzerland are currently investigating clay formations as potential host rock for the disposal of radioactive waste. In the Netherlands, clay formations have always been considered as an alternative to disposal in salt. The general interest in clays is increasing: in Germany and The United Kingdom, it was decided a few years ago that besides respectively salt and crystalline rock also clays need to be evaluated. In Eastern and Central Europe, the Slovak republic and Lithuania consider both clay and granite as possible host rocks for spent fuel while in Russia recently a project was started to study the possible disposal of low and medium level waste in a clay formation in the Leningrad area. Within the EC research and development framework programs and the OECD/NEA Clay Club, collaborations were developed between countries studying clay and with a strong involvement of SCK-CEN. The collaboration with the Eastern and Central European countries is supported through the support programme of the Belgian Ministry of Economic affairs. The objectives of these co-operations are to deliver expert services to other nuclear waste disposal programs considering clay as host rock; to to acquire broader international recognition of our expertise and support for the development of nuclear waste disposal in clay; to get a broader insight in the properties and behaviour of clays

Preoperational assessment of solute release from waste rock at proposed mining operations

International Nuclear Information System (INIS)

Lapakko, Kim A.

2015-01-01

Highlights: • Modeling to estimate solute release from waste rock at proposed mines is described. • Components of the modeling process are identified and described. • Modeling inputs required are identified and described. • Examples of data generated and their application are presented. • Challenges inherent to environmental review are identified. - Abstract: Environmental assessments are conducted prior to mineral development at proposed mining operations. Among the objectives of these assessments is prediction of solute release from mine wastes projected to be generated by the proposed mining and associated operations. This paper provides guidance to those engaged in these assessments and, in more detail, provides insights on solid-phase characterization and application of kinetic test results for predicting solute release from waste rock. The logic guiding the process is consistent with general model construction practices and recent publications. Baseline conditions at the proposed site are determined and a detailed operational plan is developed and imposed upon the site. Block modeling of the mine geology is conducted to identify the mineral assemblages present, their masses and compositional variations. This information is used to select samples, representative of waste rock to be generated, that will be analyzed and tested to describe characteristics influencing waste rock drainage quality. The characterization results are used to select samples for laboratory dissolution testing (kinetic tests). These tests provide empirical data on dissolution of the various mineral assemblages present as waste rock. The data generated are used, in conjunction with environmental conditions, the proposed method of mine waste storage, and scientific and technical principles, to estimate solute release rates for the operational scale waste rock. Common concerns regarding waste rock are generation of acidic drainage and release of heavy metals and sulfate. Key solid

Geotechnical assessment and instrumentation needs for nuclear waste isolation in crystalline and argillaceous rocks

International Nuclear Information System (INIS)

1979-01-01

To evaluate the state-of-the-art, research needs, and research priorities related to waste disposal in largely impermeable rocks, scientists and engineers working on geologic aspects of nuclear waste disposal were brought together. This report and recommendations are the proceedings from that symposium. Three panels were organized on rock properties, fracture hydrology, and geochemistry. Panel discussions and recommendations are presented

Overview of the waste/barrier/rock interactions program of the basalt waste isolation project

International Nuclear Information System (INIS)

Salter, P.F.; Burnell, J.R.; Lane, D.L.

1986-01-01

The waste package waste/barrier/rock interactions testing program of the Basalt Waste Isolation Project is designed to assess the interactions between nuclear waste forms, other waste package components, and the environment in order to evaluate long-term waste package isolation (radionuclide release) behavior. The program involves reacting fully radioactive waste forms with combinations of steel or copper container material and basalt/bentonite packing material in site-specific ground water under anticipated repository conditions to obtain the steady state radionuclide concentrations required to predictively model waste package radionuclide concentrations required to predictively model waste package radionuclide releases. Both static and flow-through autoclaves are being used in the test program to determine radionuclide concentrations as a function of time and groundwater flow rate, and to evaluate the solid phase and water chemistry changes that control those concentrations. This test program, when combined with project hydrologic and geochemical testing and modeling efforts, and natural analog studies, provides the information required to evaluate long-term radionuclide mobility within a waste package emplaced in a basalt repository

Geotechnical modeling of high-level nuclear waste disposal by rock melting

International Nuclear Information System (INIS)

Heuze, F.E.

1981-12-01

A new strategy has been developed for the geotechnical modeling of nuclear waste disposal by rock melting (DRM). Three seeparate tasks were performed to reach this objective: a review of the four scenarios which have been proposed for DRM, to date; an evaluation of computer-based numerical models which could be used to analyze the mechanical, thermal, and hydraulic processes involved in DRM; and a critical review of rock mass properties which are relevant to the design and safety of waste disposal by rock melting. It is concluded that several geotechnical aspects of DRM can be studied realistically with current state-of-the-art model capabilities and knowledge of material properties. The next step in the feasibility study of DRM should be a best-estimate calculation of the four cavity-melt and canister-burial concepts. These new analyses will indicate the most critical areas for subsequent research

Characterization of phosphorus leaching from phosphate waste rock in the Xiangxi River watershed, Three Gorges Reservoir, China.

Science.gov (United States)

Jiang, Li-Guo; Liang, Bing; Xue, Qiang; Yin, Cheng-Wei

2016-05-01

Phosphate mining waste rocks dumped in the Xiangxi River (XXR) bay, which is the largest backwater zone of the Three Gorges Reservoir (TGR), are treated as Type I industry solid wastes by the Chinese government. To evaluate the potential pollution risk of phosphorus leaching from phosphate waste rocks, the phosphorus leaching behaviors of six phosphate waste rock samples with different weathering degrees under both neutral and acidic conditions were investigated using a series of column leaching experiments, following the Method 1314 standard of the US EPA. The results indicate that the phosphorus release mechanism is solubility-controlled. Phosphorus release from waste rocks increases as pH decreases. The phosphorus leaching concentration and cumulative phosphorus released in acidic leaching conditions were found to be one order of magnitude greater than that in neutral leaching conditions. In addition, the phosphorus was released faster during the period when environmental pH turned from weak alkalinity to slight acidity, with this accelerated release period appearing when L/S was in the range of 0.5-2.0 mL/g. In both neutral and acidic conditions, the average values of Total Phosphorus (TP), including orthophosphates, polyphosphates and organic phosphate, leaching concentration exceed the availability by regulatory (0.5 mg/L) in the whole L/S range, suggesting that the phosphate waste rocks stacked within the XXR watershed should be considered as Type II industry solid wastes. Therefore, the phosphate waste rocks deposited within the study area should be considered as phosphorus point pollution sources, which could threaten the adjacent surface-water environment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Reduction of acid rock drainage using steel slag in cover systems over sulfide rock waste piles.

Science.gov (United States)

de Almeida, Rodrigo Pereira; Leite, Adilson do Lago; Borghetti Soares, Anderson

2015-04-01

The extraction of gold, coal, nickel, uranium, copper and other earth-moving activities almost always leads to environmental damage. In metal and coal extraction, exposure of sulfide minerals to the atmosphere leads to generation of acid rock drainage (ARD) and in underground mining to acid mine drainage (AMD) due to contamination of infiltrating groundwater. This study proposes to develop a reactive cover system that inhibits infiltration of oxygen and also releases alkalinity to increase the pH of generated ARD and attenuate metal contaminants at the same time. The reactive cover system is constructed using steel slag, a waste product generated from steel industries. This study shows that this type of cover system has the potential to reduce some of the adverse effects of sulfide mine waste disposal on land. Geochemical and geotechnical characterization tests were carried out. Different proportions of sulfide mine waste and steel slag were studied in leachate extraction tests. The best proportion was 33% of steel slag in dry weight. Other tests were conducted as follows: soil consolidation, saturated permeability and soil water characteristic curve. The cover system was numerically modeled through unsaturated flux analysis using Vadose/w. The solution proposed is an oxygen transport barrier that allows rain water percolation to treat the ARD in the waste rock pile. The results showed that the waste pile slope is an important factor and the cover system must have 5 m thickness to achieve an acceptable effectiveness. © The Author(s) 2015.

Effect of heterogeneity and anisotropy related to the construction method on transfer processes in waste rock piles.

Science.gov (United States)

Lahmira, Belkacem; Lefebvre, René; Aubertin, Michel; Bussière, Bruno

2016-01-01

Waste rock piles producing acid mine drainage (AMD) are partially saturated systems involving multiphase (gas and liquid) flow and coupled transfer processes. Their internal structure and heterogeneous properties are inherited from their wide-ranging material grain sizes, their modes of deposition, and the underlying topography. This paper aims at assessing the effect of physical heterogeneity and anisotropy of waste rock piles on the physical processes involved in the generation of AMD. Generic waste rock pile conditions were represented with the numerical simulator TOUGH AMD based on those found at the Doyon mine waste rock pile (Canada). Models included four randomly distributed material types (coarse, intermediate, fine and very fine-grained). The term "randomly" as used in this study means that the vertical profile and spatial distribution of materials in waste rock piles (internal structure) defy stratigraphy principles applicable to natural sediments (superposition and continuity). The materials have different permeability and capillary properties, covering the typical range of materials found in waste rock piles. Anisotropy with a larger horizontal than vertical permeability was used to represent the effect of pile construction by benches, while the construction by end-dumping was presumed to induce a higher vertical than horizontal permeability. Results show that infiltrated precipitation preferentially flows in fine-grained materials, which remain almost saturated, whereas gas flows preferentially through the most permeable coarse materials, which have higher volumetric gas saturation. Anisotropy, which depends on pile construction methods, often controls global gas flow paths. Construction by benches favours lateral air entry close to the pile slope, whereas end-dumping leads to air entry from the surface to the interior of the pile by secondary gas convection cells. These results can be useful to construct and rehabilitate waste rock piles to minimize

Oxygen influx and geochemistry of percolate water from reactive mine waste rock underlying a sloping channelled soil cover

Energy Technology Data Exchange (ETDEWEB)

Song Qing, E-mail: qsong3@uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada); Yanful, Ernest K., E-mail: eyanful@eng.uwo.ca [Geotechnical Research Center, Department of Civil and Environmental Engineering, University of Western Ontario, 1151 Richmond Street, London, ON, N6A 5B9 (Canada)

2011-05-15

Research Highlights: > A channelled cover with preferential flow can still mitigate ARD to some extent. > Oxygen ingress was more sensitive to the location of the channel than to K{sub s}. > The channel in the barrier layer was a major passage for O{sub 2} ingress. > Actual flushing was an important factor when estimating O{sub 2} decay coefficient. - Abstract: An ideal engineered soil cover can mitigate acid rock drainage (ARD) by limiting water and gaseous O{sub 2} ingress into an underlying waste rock pile. However, the barrier layer in the soil cover almost invariably tends to develop cracks or fractures after placement. These cracks may change water flow and O{sub 2} transport in the soil cover and decrease performance in the long run. The present study employed a 10-cm-wide sand-filled channel installed in a soil barrier layer (silty clay) to model the aggregate of cracks or fractures that may be present in the cover. The soil cover had a slope of 20%. Oxygen transport through the soil cover and oxidation of the underlying waste rock were investigated and compared to a controlled column test with bare waste rock (without soil cover). Moreover, gaseous O{sub 2} transport in the soil cover with channel and its sensitivity to channel location as well as the influence of the saturated hydraulic conductivity of the channel material were modeled using the commercial software VADOSE/W. The results indicted that the waste rock underlying the soil cover with channel had a lower oxidation rate than the waste rock without cover because of reduced O{sub 2} ingress and water flushing in the soil cover with channel, which meant a partial soil cover might still be effective to some extent in reducing ARD generation. Gaseous O{sub 2} ingress into the covered waste rock was more sensitive to the channel location than to the saturated hydraulic conductivity of the material filling the channel. Aqueous equilibrium speciation modeling and scanning electron microscopy with energy

A review of acid drainage from waste rock dumps and mine sites (Australian and Scandinavia)

International Nuclear Information System (INIS)

Harries, J.R.

1990-05-01

This report reviews the literature from Australia and Scandinavia on acid drainage from pyritic waste rock dumps with an emphasis on measurements and theory of processes that control the rage of oxidation and the release of pollutants. Conditions within waste rock dumps have been measured at several mine sites and a range of rehabilitation treatments have been tried to reduce the release of pollutants. A number of models have been proposed to calculate air flow, water transport and geochemistry. The data and experience at the mine sites are compared with predictions of the models. Details of Australian and Swedish mine sites where waste rock is a source of acid drainage are described in the Appendices. 92 refs., 2 tabs., 10 figs

Geotechnical site assessment for underground radioactive waste disposal in rock

International Nuclear Information System (INIS)

Hudson, J.A.

1986-05-01

This report contains a state-of-the-art review of the geotechnical assessment of Land 3 and Land 4 repository sites (at 100 - 300 m depth in rock) for intermediate level radioactive waste disposal. The principles established are also valid for the disposal of low and high level waste in rock. The text summarizes the results of 21 DoE research contract reports, firstly 'in series' by providing a technical review of each report and then 'in parallel' by considering the current state of knowledge in the context of the subjects in an interaction matrix framework. 1214 references are cited. It is concluded that four further research projects are required for site assessment procedures to be developed or confirmed. These are coupled modelling, mechanical properties, water flow and establishment of 2 phase site assessment procedures. (author)

Creep in crystalline rock with application to high level nuclear waste repository

International Nuclear Information System (INIS)

Eloranta, P.; Simonen, A.

1992-06-01

The time-dependent strength and deformation properties of hard crystalline rock are studied. Theoretical models defining the phenomena which can effect these properties are reviewed. The time- dependent deformation of the openings in the proposed nuclear waste repository is analysed. The most important factors affecting the subcritical crack growth in crystalline rock are the stress state, the chemical environment, temperature and microstructure of the rock. There are several theoretical models for the analysis of creep and cyclic fatigue: deformation diagrams, rheological models thermodynamic models, reaction rate models, stochastic models, damage models and time-dependent safety factor model. They are defective in describing the three-axial stress condition and strength criteria. In addition, the required parameters are often too difficult to determine with adequate accuracy. Therefore these models are seldom applied in practice. The effect of microcrack- driven creep on the stability of the work shaft, the emplacement tunnel and the capsulation hole of a proposed nuclear waste repository was studied using a numerical model developed by Atomic Energy of Canada Ltd. According to the model, the microcrack driven creep progresses very slowly in good quality rock. Poor rock quality may accelerate the creep rate. The model is very sensitive to the properties of the rock and secondary stress state. The results show that creep causes no stability problems on excavations in good rock. The results overestimate the effect of the creep, because the analysis omitted the effect of support structures and backfilling

Basic rock properties for the thermo-hydro-mechanical analysis of a high-level radioactive waste repository

Energy Technology Data Exchange (ETDEWEB)

Kim, Jhin Wung; Kang, Chul Hyung

1999-04-01

Deep geological radioactive waste disposal is generally based on the isolation of the waste from the biosphere by multiple barriers. The host rock is one of these barriers which should provide a stable mechanical and chemical environment for the engineered barriers. In the evaluation of the safety of the high-level radioactive waste disposal systems, an important part of the safety analysis is an assessment of the coupling or interaction between thermal, hydrological, and mechanical effects. In order to do this assessment, adequate data on the characteristics of different host rocks are necessary. The properties of the rock and rock discontinuity are very complex and their values vary in a wide range. The accuracy of the result of the assessment depends on the values of these properties used. The present study is an attempt to bring together and condense data for the basic properties of various rock masses, which are needed in the thermo-hydro-mechanical analysis for the deep geological radioactive waste repository. The testing and measurement methods for these basic properties are also presented. Domestic data for deep geological media should be supplemented in the future, due to the insufficiency and the lack of accuracy of the data available at present. (author). 28 refs., 21 figs.

Basic rock properties for the thermo-hydro-mechanical analysis of a high-level radioactive waste repository

International Nuclear Information System (INIS)

Kim, Jhin Wung; Kang, Chul Hyung

1999-04-01

Deep geological radioactive waste disposal is generally based on the isolation of the waste from the biosphere by multiple barriers. The host rock is one of these barriers which should provide a stable mechanical and chemical environment for the engineered barriers. In the evaluation of the safety of the high-level radioactive waste disposal systems, an important part of the safety analysis is an assessment of the coupling or interaction between thermal, hydrological, and mechanical effects. In order to do this assessment, adequate data on the characteristics of different host rocks are necessary. The properties of the rock and rock discontinuity are very complex and their values vary in a wide range. The accuracy of the result of the assessment depends on the values of these properties used. The present study is an attempt to bring together and condense data for the basic properties of various rock masses, which are needed in the thermo-hydro-mechanical analysis for the deep geological radioactive waste repository. The testing and measurement methods for these basic properties are also presented. Domestic data for deep geological media should be supplemented in the future, due to the insufficiency and the lack of accuracy of the data available at present. (author). 28 refs., 21 figs

Hydrological and thermal issues concerning a nuclear waste repository in fractured rocks

International Nuclear Information System (INIS)

Wang, J.S.Y.

1991-12-01

The characterization of the ambient conditions of a potential site and the assessment of the perturbations induced by a nuclear waste repository require hydrological and thermal investigations of the geological formations at different spatial and temporal scales. For high-level wastes, the near-field impacts depend on the heat power of waste packages and the far-field long-term perturbations depend on the cumulative heat released by the emplaced wastes. Surface interim storage of wastes for several decades could lower the near-field impacts but would have relatively small long-term effects if spent fuels were the waste forms for the repository. One major uncertainty in the assessment of repository impacts is from the variation of hydrological properties in heterogeneous media, including the effects of fractures as high-permeability flow paths for containment migration. Under stress, a natural fracture cannot be represented by the parallel plate model. The rock surface roughness, the contact area, and the saturation state in the rock matrix could significantly change the fracture flow. In recent years, the concern of fast flow through fractures in saturated media has extended to the unsaturated zones. The interactions at different scales between fractures and matrix, between fractured matrix unites and porous units, and between formations and faults are discussed

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 5. Baseline rock properties-granite

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM-36/5, Baseline Rock Properties--Granite, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. This report, on the rock properties of typical granites, includes an evaluation of the various test results reported in the literature. Firstly, a literature survey was made in order to obtain a feel for the range of rock properties encountered. Then, granites representative of different geologic ages and from different parts of the United States were selected and studied in further detail. Some of the special characteristics of granite, such as anisotropy, creep and weathering were also investigated. Lastly, intact properties for a typical granite were selected and rock mass properties were derived using appropriate correction factors

Proceedings of the symposium on the management and rehabilitation of waste rock dumps

International Nuclear Information System (INIS)

Riley, S.R.; Waggitt, P.W.; McQuade, C.

1993-01-01

Waste rock management and rehabilitation are issues with economic, legal and scientific ramifications which may have significant effects on the viability and profitability of mining operations. Through this symposium the Office of the Supervising Scientist and the Australasian Institute of Mining and Metallurgy (Darwin branch) brought together five key disciplines essential for the efficient design and long term management of waste rock dump, planning and economics, hydrology, geochemistry, biology and geotechnics. The symposium was targeted at industry personnel who make the decisions in design planning and day-to-day management. Two out of the 13 papers have been separately indexed

Characterization of the material produced using marble waste and reagents aiminig production of rock wool

International Nuclear Information System (INIS)

Rodrigues, Girley Ferreira; Espinosa, Denise Crocce Romano; Tenorio, Jorge Alberto Soares; Alves, Joner Oliveira

2010-01-01

The aim of this work was to characterize materials produced from the mixture of marble waste and chemical reagents. The materials were homogenized, melted and cooled in order to obtain materials with similar characteristics of rock wools. The batch was poured in a water-filled recipient and also in a Herty viscometer at three temperatures. Samples of produced materials were characterized by X-ray diffraction, scanning electron microscopy and differential thermal analysis. Results of this study indicate that it is possible the incorporation of marble waste in the production process of rock wool, replacing approximately 15% of the raw material used to fabricate this material. This process represents a technological breakthrough since it allows the reuse of marble waste, and also represents a possible decrease in rock wool production cost, which is a material with a growing market as thermo acoustic insulator. (author)

Exploring the techno-economic feasibility of mine rock waste utilisation in road works: The case of a mining deposit in Ghana.

Science.gov (United States)

Agyeman, Stephen; Ampadu, Samuel I K

2016-02-01

Mine rock waste, which is the rock material removed in order to access and mine ore, is free from gold processing chemical contaminants but presents a significant environmental challenge owing to the large volumes involved. One way of mitigating the environmental and safety challenges posed by the large volume of mine rock waste stockpiled in mining communities is to find uses of this material as a substitute for rock aggregates in construction. This article reports on a study conducted to evaluate the engineering properties of such a mine deposit to determine its suitability for use as road pavement material. Samples of mine rock waste, derived from the granitic and granodioritic intrusive units overlying the gold-bearing metavolcanic rock and volcano-clastic sediments of a gold mining area in Ghana, were obtained from three mine rock waste disposal facilities and subjected to a battery of laboratory tests to determine their physical, mechanical, geotechnical, geometrical and durability properties. The overall conclusion was that the mine rock waste met all the requirements of the Ghana Ministry of Transportation specification for use as aggregates for crushed rock subbase, base and surface dressing chippings for road pavements. The recommendation is to process it into the required sizes for the various applications. © The Author(s) 2015.

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of South Carolina

International Nuclear Information System (INIS)

Secor, D.T. Jr.

1980-10-01

This report reviews the geology of the Piedmont Province of South Carolina with the aim of designating rock units favorable for field exploration for a potential underground repository for the storage of radioactive waste. Most of the rocks in the South Carolina Piedmont are metamorphosed sedimentary volcanic or igneous rocks that have experienced at least one episode of strong deformation. As a consequence of this deformation, they have irregular shapes, making it difficult to predict their subsurface extent. In evaluating the suitability of the rock units for radioactive waste storage, certain criteria were found to be particularly useful. The requirements that the storage site be located in a large volume of homogeneous, impermeable, relatively unfractured rock was the most important criteria in eliminating most of the Piedmont rock units for consideration as field study areas. Six large late- to post-tectonic igneous plutons (Winnsboro, Liberty Hill, Ogden, Newberry, Lowrys, and Bald Rock) are recommended as field study areas

Damage-plasticity model of the host rock in a nuclear waste repository

Energy Technology Data Exchange (ETDEWEB)

Koudelka, Tomáš; Kruis, Jaroslav, E-mail: kruis@fsv.cvut.cz [Department of Mechanics, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

2016-06-08

The paper describes damage-plasticity model for the modelling of the host rock environment of a nuclear waste repository. Radioactive Waste Repository Authority in Czech Republic assumes the repository to be in a granite rock mass which exhibit anisotropic behaviour where the strength in tension is lower than in compression. In order to describe this phenomenon, the damage-plasticity model is formulated with the help of the Drucker-Prager yield criterion which can be set to capture the compression behaviour while the tensile stress states is described with the help of scalar isotropic damage model. The concept of damage-plasticity model was implemented in the SIFEL finite element code and consequently, the code was used for the simulation of the Äspö Pillar Stability Experiment (APSE) which was performed in order to determine yielding strength under various conditions in similar granite rocks as in Czech Republic. The results from the performed analysis are presented and discussed in the paper.

Site-specific evaluation of safety issues for high-level waste disposal in crystalline rocks. Final report

Energy Technology Data Exchange (ETDEWEB)

Jobmann, M. (ed.) [DBE Technology GmbH, Peine (Germany)

2016-03-31

In the past, German research and development (R and D) activities regarding the disposal of radioactive waste, including spent nuclear fuel, focused mainly on domal rock salt because rock salt was the preferred host rock formation. In addition, generic R and D work regarding alternative host rocks (crystalline rocks and claystones) had been performed as well for a long time but with lower intensity. Around the year 2000, as a consequence of the moratorium on the Gorleben site, the Federal Government decided to have argillaceous rocks and crystalline rocks investigated in more detail. As Germany does not have any underground research and host rock characterization facilities, international cooperation received a high priority in the German R and D programme for high-level waste (HLW) disposal in order to increase the knowledge regarding alternative host rocks. Major cornerstones of the cooperation are joint projects and experiments conducted especially in underground research laboratories (URL) in crystalline rocks at the Grimsel Test Site (Switzerland) and the Hard Rock Laboratory (HRL) Aespoe(Sweden) and in argillaceous rocks at the URL Mont Terri (Switzerland) and Bure (France). In 2001, the topic of radioactive waste disposal was integrated into the agreement between the former Russian Ministry of Atomic Energy (Minatom, now Rosatom) and the German Ministry of Labor (BMWA), now Ministry of Economic Affairs and Energy (BMWi), on cooperation regarding R and D on the peaceful utilization of nuclear power (agreement on ''Wirtschaftlich-Technische Zusammenarbeit'' WTZ). The intention was to have a new and interesting opportunity for international R and D cooperation regarding HLW disposal in crystalline rocks and the unique possibility to perform site-specific work, to test the safety demonstration tools available, and to expand the knowledge to all aspects specific to these host rocks. Another motivation for joining this cooperation was the

National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

International Nuclear Information System (INIS)

Smedes, H.W.

1983-04-01

A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions

National survey of crystalline rocks and recommendations of regions to be explored for high-level radioactive waste repository sites

Energy Technology Data Exchange (ETDEWEB)

Smedes, H.W.

1983-04-01

A reconnaissance of the geological literature on large regions of exposed crystalline rocks in the United States provides the basis for evaluating if any of those regions warrant further exploration toward identifying potential sites for development of a high-level radioactive waste repository. The reconnaissance does not serve as a detailed evaluation of regions or of any smaller subunits within the regions. Site performance criteria were selected and applied insofar as a national data base exists, and guidelines were adopted that relate the data to those criteria. The criteria include consideration of size, vertical movements, faulting, earthquakes, seismically induced ground motion, Quaternary volcanic rocks, mineral deposits, high-temperature convective ground-water systems, hydraulic gradients, and erosion. Brief summaries of each major region of exposed crystalline rock, and national maps of relevant data provided the means for applying the guidelines and for recommending regions for further study. It is concluded that there is a reasonable likelihood that geologically suitable repository sites exist in each of the major regions of crystalline rocks. The recommendation is made that further studies first be conducted of the Lake Superior, Northern Appalachian and Adirondack, and the Southern Appalachian Regions. It is believed that those regions could be explored more effectively and suitable sites probably could be found, characterized, verified, and licensed more readily there than in the other regions.

Acceptance criteria for disposal of radioactive wastes in shallow ground and rock cavities

International Nuclear Information System (INIS)

1985-01-01

This document provides an overview of basic information related to waste acceptance criteria for disposal in shallow ground and rock cavity repositories, consisting of a discussion of acceptable waste types. The last item includes identification of those waste characteristics which may influence the performance of the disposal system and as such are areas of consideration for criteria development. The material is presented in a manner similar to a safety assessment. Waste acceptance criteria aimed at limiting the radiation exposure to acceptable levels are presented for each pathway. Radioactive wastes considered here are low-level radioactive wastes and intermediate-level radioactive wastes from nuclear fuel cycle operations and applications of radionuclides in research, medicine and industry

Release consequence analysis for a hypothetical geologic radioactive waste repository in hard rock

International Nuclear Information System (INIS)

1979-12-01

This report makes an evaluation of the long-term behaviour of the wastes placed in a hard rock repository. Impacts were analyzed for the seven reference fuel cycles of WG 7. The reference repository for this study is for granitic rock or gneiss as the host rock. The descriptions of waste packages and repository facilities used in this study represent only one of many possible designs based on the multiple barriers concept. The repository's size is based on a nuclear economy producing 100 gigawatts of electricity per year for 1 year. The objective of the modeling efforts presented in this study is to predict the rate of transport of radioactive contaminants from the repository through the geosphere to the biosphere and thus determine an estimate of the potential dose to humans so that the release consequence impacts of the various fuel cycles can be compared. Currently available hydrologic, leach, transport, and dose models were used in this study

Use of ornamental rock waste to fabricate rustic ceramic tile: industrial test

International Nuclear Information System (INIS)

Pacheco, A.T.; Monteiro, S.N.

2011-01-01

This work has as its objective to produce rustic wall tiles with the use of a waste from the sawing of gnaisse rock mixed with kaolinitic replacing sand. Compositions were prepared using clay, sand and waste, The wall tiles were fire in a industrial dome type furnace at 850 deg C.The physical and mechanical properties determined were water absorption and flexural rupture strength. The results indicated that the waste did not improve the evaluated properties by replacing sand. This is mainly due to the low temperature used in the experiment. (author)

Retrievability of high-level nuclear waste from geologic repositories - Regulatory and rock mechanics/design considerations

International Nuclear Information System (INIS)

Tanious, N.S.; Nataraja, M.S.; Daemen, J.J.K.

1987-01-01

Retrievability of nuclear waste from high-level geologic repositories is one of the performance objectives identified in 10CFR60 (Code of Federal Regulations, 1985). 10CFR60.111 states that the geologic repository operations area shall be designed to preserve the option of waste retrieval. In designing the repository operations area, rock mechanics considerations play a major role especially in evaluating the feasibility of retrieval operations. This paper discusses generic considerations affecting retrievability as they relate to repository design, construction, and operation, with emphasis on regulatory and rock mechanics aspects

Rheological characteristics of waste rock materials in abandoned mine deposit and debris flow hazards

Science.gov (United States)

Jeong, Sueng-Won; Lee, Choonoh; Cho, Yong-Chan; Wu, Ying-Hsin

2015-04-01

In Korea, approximately 5,000 metal mines are spread, but 50% of them are still abandoned without any proper remediation and cleanup. Summer heavy rainfall can result in the physicochemical modification of waste rock materials in the mountainous. From the geotechnical monitoring and field investigation, there are visible traces of mass movements every year. Soil erosion is one of severe phenomena in the study area. In particular, study area is located in the upper part of the Busan Metropolitan City and near the city's water supply. With respect to the supply of drinking water and maintenance of ecological balance, proper disposal of waste rock materials is required. For this reason, we examine the rheological properties of waste rock materials as a function of solid content using a ball- and vane-penetrated rheometer. In the flow curves, which are the relationship between the shear stress and shear rate of waste rock materials, we found that the soil samples exhibited a shear thinning beahivor regardless of solid content. The Bingham, Herschel-Bulkley, Power-law, and Papanastasiou models are used to determine the rheological properties. Assuming that the soil samples behaved as the viscoplastic behavior, the yield stress and viscosity are determined for different water contents. As a result, there are clear relationships between the solid content and rheological values (i.e., Bingham yield stress and plastic viscosity). From these relationships, the maximum and minimum of Bingham yield stresses are ranged from 100 to 2000 Pa. The debris flow mobilization is analysed using a 1D BING and 2D Debris flow models. In addition, the effect of wall slip and test apparatus are discussed.

Long-term temporal variability of the radon-222 exhalation flux from a landform covered by low uranium grade waste rock

International Nuclear Information System (INIS)

Bollhöfer, Andreas; Doering, Che

2016-01-01

Radon-222 exhalation flux densities from two different substrates of several metres thickness, waste rock and waste rock mixed with approximately 30% lateritic material, were measured over a period of five years in the wet-dry tropics of Northern Australia. Fourteen measurement campaigns using activated charcoal canisters (n > 1000) covered both dry and wet seasons and showed differences in seasonal and long term trends of the "2"2"2Rn exhalation flux densities normalised to the "2"2"6Ra activity concentrations of the substrate. Dry season "2"2"2Rn exhalation was generally higher for the mixed substrate, due to the larger fraction of fines. Seasonality established within the first year of landform construction on the mixed substrate, due to the higher water holding capacity of the lateritic material. In contrast, waste rock only shows no seasonality until years four and five after construction, when average normalised dry season "2"2"2Rn exhalation flux densities from waste rock increase to values (0.47 ± 0.06 mBq m"−"2 s"−"1 per Bq kg"−"1) similar to the mixed substrate (0.64 ± 0.08 mBq m"−"2 s"−"1 per Bq kg"−"1), likely due to an increase in fines from rapid weathering of the schistose waste rock. Volumetric water content has been used to parametrize relative "2"2"2Rn exhalation and we determined that wet season "2"2"2Rn exhalation is about 40% of the dry season exhalation. - Highlights: • We determined "2"2"2Rn exhalation flux densities normalised to "2"2"6Ra activity concentrations (R_E_-_R) for two substrates. • R_E_-_R was lower for waste rock only compared to waste rock blended with 30% fine grained lateritic material. • Seasonality in waste rock "2"2"2Rn exhalation flux densities established 4 years after construction. • Wet season R_E_-_R was about 40% of the dry season R_E_-_R.

Weathering behavior of mine tailings and waste rock: A surface investigation

International Nuclear Information System (INIS)

Domvile, S.J.; Li, M.G.; Sollner, D.D.; Nesbitt, W.

1994-01-01

A study focusing on the ion movement in the near surface of sulfide minerals was conducted to better understand the weathering mechanisms of mine waste materials. Tailings and waste rock samples from Canadian mines were subjected to controlled weathering studies using various chemical leachants. Leachates were analyzed for various parameters, and petrographic analyses were conducted on the solid residues. Laboratory oxidation studies of pure pyrrhotite and arsenopyrite were carried out using the surface techniques X-ray photoelectron spectroscopy (XPS) and auger electron spectroscopy (AES). The data derived from the weathering study and the surface techniques were correlated to determine mechanisms of oxidation. Several results were observed during the project: ferric iron constitutes one third of the iron present in pyrrhotite, sulfide oxidation is initiated when rock is blasted, sulfide sulfur is oxidized to di- and poly-sulfides prior to forming sulfates, and significantly more sulfate is produced upon exposure to aqueous environments than to air alone

Chemical modeling of irreversible reactions in nuclear waste-water-rock systems

International Nuclear Information System (INIS)

Wolery, T.J.

1981-02-01

Chemical models of aqueous geochemical systems are usually built on the concept of thermodynamic equilibrium. Though many elementary reactions in a geochemical system may be close to equilibrium, others may not be. Chemical models of aqueous fluids should take into account that many aqueous redox reactions are among the latter. The behavior of redox reactions may critically affect migration of certain radionuclides, especially the actinides. In addition, the progress of reaction in geochemical systems requires thermodynamic driving forces associated with elementary reactions not at equilibrium, which are termed irreversible reactions. Both static chemical models of fluids and dynamic models of reacting systems have been applied to a wide spectrum of problems in water-rock interactions. Potential applications in nuclear waste disposal range from problems in geochemical aspects of site evaluation to those of waste-water-rock interactions. However, much further work in the laboratory and the field will be required to develop and verify such applications of chemical modeling

Nuclear waste. DOE has terminated research evaluating crystalline rock for a repository

International Nuclear Information System (INIS)

Fultz, Keith O.; Sprague, John W.; Weigel, Dwayne E.; Price, Vincent P.

1989-05-01

We found that DOE terminated funding of research projects specifically designed to evaluate the suitability of crystalline rock for a repository. DOE continued other research efforts involving crystalline rock because they will provide information that it considers useful for evaluating the suitability of Yucca Mountain, Nevada, for a potential repository. Such research activities are not prohibited by the amendments. In January 1988, DOE began evaluating both its domestic and international research programs to ensure their compliance with the 1987 amendments. Several DOE offices and contractors were involved in the evaluation. DOE officials believe that the evaluation effectively brought the Office of Civilian Radioactive Waste Management activities into compliance with the amendments while maintaining useful international relations of continuing benefit to the nuclear waste program in general and to DOE's investigation of the Yucca Mountain site in particular. (The 1987 amendments designated Yucca Mountain as the only site that DOE is to investigate for a potential repository.) The approach and results of DOE's evaluation are discussed. Our review of DOE documents indicates that, by June 22, 1988, DOE completed its evaluation of ongoing crystalline rock research projects to ensure compliance with the 1987 amendments, terminated those research activities it identified as being specifically designed to evaluate the suitability of crystalline rock for a repository, continued some research activities involving crystalline rock because these activities would benefit the investigation and development of the Yucca Mountain repository site, and redirected some research activities so that they would contribute to investigating and developing the Yucca Mountain site

Investigation on the oxygen transport mechanisms in the Sarcheshmeh waste rock dumps

Directory of Open Access Journals (Sweden)

Saeed Yousefi

2015-04-01

Full Text Available Introduction Pyrite oxidation and acid mine drainage (AMD are the serious environmental problems associated with the mining activities in sulphide ores. The rate of pyrite oxidation is governed by the availability of oxygen (Borden, 2003. Therefore, the identifying oxygen supplying mechanism is one of the most important issues related to the environmental assessment of waste rock dumps (Cathles and Apps, 1975; Jaynes et al., 1984; Davis and Ritchie, 1986. Although comprehensive researches were performed on the mathematical description of oxygen transport processes using the numerical modeling (Morin et al., 1988; Blowes et al., 1991; Wunderly et al., 1986; Elberling et al., 1994; Jannesar Malakooti et al., 2014, so far, the interactions between these processes and geochemical and mineralogical characteristics has not been studied especially in waste rock dumps. Therefore the main objective of this study is to identify the evidences for knowing the oxygen transport mechanisms in the waste dumps and also, its role in intensity of pyrite oxidation. It is expected that such these structural studies could be useful for better understanding of dominant processes in numerical modeling and also providing environmental management strategies in the study area and other sites by similar characteristics. Materials and Methods In this study, thirty solid samples were collected from six excavated trenches in the waste rock dumps No. 19 and 31 of the Sarcheshmeh porphyry copper mine. Collected samples were studied using several methods such as XRD, ASTM-D2492, paste pH and grain size distribution. The results obtained from these methods were used with the field observations in order to characterize some detail information about oxygen supplying mechanisms for oxidation reactions in the waste rock dumps. Result The main minerals found by the XRD analysis were quartz and muscovite which were present in all samples. Pyrite, orthose, albite, and chlorite were also

Pirm wastes: permanent isolation in rock-forming minerals

International Nuclear Information System (INIS)

Smyth, J.R.; Vidale, R.J.; Charles, R.W.

1977-01-01

The most practical system for permanent isolation of radioactive wastes in granitic and pelitic environments may be one which specifically tailors the waste form to the environment. This is true because if recrystallization of the waste form takes place within the half-lives of the hazardous radionuclides, it is likely to be the rate-controlling step for release of these nuclides to the ground-water system. The object of the proposed waste-form research at Los Alamos Scintific Laboratory (LASL) is to define a phase assemblage which will minimize chemical reaction with natural fluids in a granitic or pelitic environment. All natural granites contain trace amounts of all fission product elements (except Tc) and many contain minor amounts of these elements as major components of certain accessory phases. Observation of the geochemistry of fission-product elements has led to the identification of the natural minerals as target phases for research. A proposal is made to experimentally determine the amounts of fission product elements which can stably be incorporated into the phases listed below and to determine the leachability of the assemblage this produced using fluids typical of the proposed environments at the Nevada Test Site. This approach to waste isolation satisfies the following requirements: (1) It minimizes chemical reaction with the environment (i.e., recrystallization) which is likely to be the rate-controlling step for release of radionuclides to groundwater; (2) Waste loading (hence temperature) can be easily varied by dilution with material mined from the disposal site; (3) No physical container is required; (4) No maintenance is required (permanent); (5) The environment acts as a containment buffer. It is proposed that such wastes be termed PIRM wastes, for Permanent Isolation in Rock-forming Minerals

Review of important rock mechanics studies required for underground high level nuclear waste repository program

Energy Technology Data Exchange (ETDEWEB)

Kwon, S.; Cho, W. J

2007-01-15

Disposal concept adapting room and pillar method, which is a confirmed technique in mining and tunnel construction for long time, has advantages at cost, safety, technical feasibility, flexibility, and international cooperation point of views. Then the important rock mechanics principals and in situ and laboratory tests for understanding the behavior of rock, buffer, and backfill as well as their interactions will be reviewed. The accurate understanding of them is important for developing a safe disposal concept and successful operation of underground repository for permanent disposal of radioactive wastes. First of all, In this study, current status of rock mechanics studies for HLW disposal in foreign countries such as Sweden, USA, Canada, Finland, Japan, and France were reviewed. After then the in situ and laboratory tests for site characterization were summarized. Furthermore, rock mechanics studies required during the whole procedure for the disposal project from repository design to the final closure will be reviewed systematically. This study will help for developing a disposal system including site selection, repository design, operation, maintenance, and closure of a repository in deep underground rock. By introducing the required rock mechanics tests at different stages, it would be helpful from the planning stage to the operation stage of a radioactive waste disposal project.

Review of important rock mechanics studies required for underground high level nuclear waste repository program

International Nuclear Information System (INIS)

Kwon, S.; Cho, W. J.

2007-01-01

Disposal concept adapting room and pillar method, which is a confirmed technique in mining and tunnel construction for long time, has advantages at cost, safety, technical feasibility, flexibility, and international cooperation point of views. Then the important rock mechanics principals and in situ and laboratory tests for understanding the behavior of rock, buffer, and backfill as well as their interactions will be reviewed. The accurate understanding of them is important for developing a safe disposal concept and successful operation of underground repository for permanent disposal of radioactive wastes. First of all, In this study, current status of rock mechanics studies for HLW disposal in foreign countries such as Sweden, USA, Canada, Finland, Japan, and France were reviewed. After then the in situ and laboratory tests for site characterization were summarized. Furthermore, rock mechanics studies required during the whole procedure for the disposal project from repository design to the final closure will be reviewed systematically. This study will help for developing a disposal system including site selection, repository design, operation, maintenance, and closure of a repository in deep underground rock. By introducing the required rock mechanics tests at different stages, it would be helpful from the planning stage to the operation stage of a radioactive waste disposal project

Modeling of thermal evolution of near field area around single pit mode nuclear waste canister disposal in soft rocks

International Nuclear Information System (INIS)

Bajpai, R.K.; Verma, A.K.; Maheshwar, Sachin

2016-01-01

Soft rocks like argillites/shales are under consideration worldwide as host rock for geological disposal of vitrified as well as spent fuel nuclear waste. The near field around disposed waste canister at 400-500m depth witnesses a complex heat field evolution due to varying thermal characteristics of rocks, coupling with hydraulic processes and varying intensity of heat flux from the canister. Smooth heat dissipation across the rock is desirable to avoid buildup of temperature beyond design limit (100 °C) and resultant micro fracturing due to thermal stresses in the rocks and intervening buffer clay layers. This also causes enhancement of hydraulic conductivity of the rocks, radionuclide transport and greater groundwater ingress towards the canister. Hence heat evolution modeling constitutes an important part of safety assessment of geological disposal facilities

Waste disposal in granitic rocks: analysis of thermal microcracks

International Nuclear Information System (INIS)

Montoto, M.; Roeshoff, K.; Leojon, B.; Bel-Lan, A.

1981-04-01

The possible development of microcracks from a thermal origin has been researched in the granitic rocks of Shipa (Sweden), within which in a real scale have been originated some thermal gradients similar to the ones which could take place in the waste disposal. To achieve an optimal fratographic information, with some petrographic meaning, different microscopic techniques, optical and electronic, have been combined and an automatized quantification methodology has also been developed by means of digitals. Between warmed and unwarmed granitis no microfractographic differences have been detected. The observed variations are only apparent and may be explained as a function of the inherent petrographic heterogeneity of rocky blocks. In any case in the internal temperatures generated within these rocks have not attained its own threshold of thermal microcracking. (author)

Autogenous Tumbling Media Assessment to Clean Weathered Surfaces of Waste-Rock Particles from a Basalt Quarry

Directory of Open Access Journals (Sweden)

Baran Tufan

2015-06-01

Full Text Available In this study, the optimum feed composition in autogenous tumbling of basalt waste-rock particles to clean their weathered surface was determined. The weathered surfaces of basalt are generally cut out consequent to extraction of basalt columns in quarry operations. The inefficiently cut out portions of basalt cause formation of huge quarry waste dumps causing visual pollution on roadsides. Mixtures of different particle size fractions of basalt waste-rock particles were experimented to achieve the optimum feed material composition. The minimum loss of commercially available basalt particles and maximum clear surface was intended. The results were compared with respect to weight loss (% and reflectance values of used and generated samples.

Microorganisms in potential host rocks for geological disposal of nuclear waste and their interactions with radionuclides

Energy Technology Data Exchange (ETDEWEB)

Cherkouk, A.; Liebe, M.; Luetke, L.; Moll, H.; Stumpf, T. [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

2015-07-01

The long-term safety of nuclear waste in a deep geological repository is an important issue in our society. Microorganisms indigenous to potential host rocks are able to influence the oxidation state, speciation and therefore the mobility of radionuclides as well as gas generation or canister corrosion. Therefore, for the safety assessment of such a repository it is necessary to know which microorganisms are present in the potential host rocks (e.g. clay, salt) and if these microorganisms can influence the performance of a repository. Microbial diversity in potential host rocks for geological disposal of nuclear waste was analyzed by culture-independent molecular biological methods (e.g. 16S rRNA gene retrieval) as well as enrichment and isolation of indigenous microbes. Among other isolates, a Paenibacillus strain, as a representative of Firmicutes, was recovered in R2A media under anaerobic conditions from Opalinus clay from the Mont Terri in Switzerland. Accumulation experiments and potentiometric titrations showed a strong interaction of Paenibacillus sp. cells with U(VI) within a broad pH range (3-7). Additionally, the interactions of the halophilic archaeal strain Halobacterium noricense DSM 15987, a salt rock representative reference strain, with U(VI) at high ionic strength was investigated. After 48 h the cells were still alive at uranium concentrations up to 60 μM, which demonstrates that Halobacterium noricense can tolerate uranium concentrations up to this level. The formed uranium sorption species were examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). The results about the microbial communities present in potential host rocks for nuclear waste repositories and their interactions with radionuclides contribute to the safety assessment of a prospective nuclear waste repository.

Microorganisms in potential host rocks for geological disposal of nuclear waste and their interactions with radionuclides

International Nuclear Information System (INIS)

Cherkouk, A.; Liebe, M.; Luetke, L.; Moll, H.; Stumpf, T.

2015-01-01

The long-term safety of nuclear waste in a deep geological repository is an important issue in our society. Microorganisms indigenous to potential host rocks are able to influence the oxidation state, speciation and therefore the mobility of radionuclides as well as gas generation or canister corrosion. Therefore, for the safety assessment of such a repository it is necessary to know which microorganisms are present in the potential host rocks (e.g. clay, salt) and if these microorganisms can influence the performance of a repository. Microbial diversity in potential host rocks for geological disposal of nuclear waste was analyzed by culture-independent molecular biological methods (e.g. 16S rRNA gene retrieval) as well as enrichment and isolation of indigenous microbes. Among other isolates, a Paenibacillus strain, as a representative of Firmicutes, was recovered in R2A media under anaerobic conditions from Opalinus clay from the Mont Terri in Switzerland. Accumulation experiments and potentiometric titrations showed a strong interaction of Paenibacillus sp. cells with U(VI) within a broad pH range (3-7). Additionally, the interactions of the halophilic archaeal strain Halobacterium noricense DSM 15987, a salt rock representative reference strain, with U(VI) at high ionic strength was investigated. After 48 h the cells were still alive at uranium concentrations up to 60 μM, which demonstrates that Halobacterium noricense can tolerate uranium concentrations up to this level. The formed uranium sorption species were examined with time-resolved laser-induced fluorescence spectroscopy (TRLFS). The results about the microbial communities present in potential host rocks for nuclear waste repositories and their interactions with radionuclides contribute to the safety assessment of a prospective nuclear waste repository.

The far field heating effects of a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1978-01-01

Fission product heating of the rock surrounding a depository for high level radioactive waste, will result in high temperatures and high thermal gradients over distances of several hundred metres for many centuries. The consequent thermal expansion of the rock leads to stresses which could alter the fracture pattern and therefore the permeability of the rock. These problems are assessed by considering an idealised model of a depository for which analytic solutions to the temperature and stress fields are derived. A related problem is that any water present in the fissures will tend to rise because of its decrease in density on heating. If the water had previously leached away some of the radionuclides in the waste, then this convective transport constitutes a possible leakage path back to the biosphere. For the low permeabilities expected at a depository site, it is possible to linearise the resulting equations and derive analytic solutions for the flow velocities. This procedure has been carried out for the idealised depository model, in order to estimate the magnitude of these effects

The design on high slope stabilization in waste rock sites of uranium mines

International Nuclear Information System (INIS)

Liu Taoan; Zhou Xinghuo; Liu Jia

2005-01-01

Design methods, reinforcement measures, and flood control measures concerning high slope stabilization in harnessing waste rock site are described in brief according to some examples of two uranium mines in Hunan province. (authors)

Geological disposal of high-level radioactive waste. Conceptual repository design in hard rock

International Nuclear Information System (INIS)

Beale, H.; Griffin, J.R.; Davies, J.W.; Burton, W.R.

1980-01-01

The paper gives an interim report on UK studies on possible designs for a repository for vitrified high-level radioactive waste in crystalline rock. The properties of the waste are described and general technical considerations of consequences of disposal in the rock. As an illustration, two basic designs are described associated with pre-cooling in an intermediate store. Firstly, a 'wet repository' is outlined wherein canisters are sealed up closely in boreholes in the rock in regions of low groundwater movement. Secondly, a 'dry repository' above sea level is described where emplacement in tunnels is followed by a loose backfill containing activity absorbers. A connection to deep permeable strata maintains water levels below emplacement positions. Variants on the two basic schemes (tunnel emplacement in a wet repository and in situ cooling) are also assessed. It is concluded that all designs discussed produce a size of repository feasible for construction in the UK. Further, (1) a working figure of 100 0 C per maximum rock temperature is not exceeded, (2) no insuperable engineering problems have so far been found, though rock mechanics studies are at an early stage; (3) it is not possible to discount the escape of a few long-lived 'man-made' isotopes. A minute increment to natural activity in the biosphere may occur from traces of uranium and its decay chains; (4) at this stage, all the designs are still possible candidates for the construction of a UK repository. (author)

Far-field thermomechanical response of argillaceous rock to emplacement of a nuclear-waste repository

International Nuclear Information System (INIS)

McVey, D.F.; Thomas, R.K.; Lappin, A.R.

1980-08-01

Before heat-producing wastes can be emplaced safely in any argillaceous rock, it will be necessary to understand the far-field thermal and thermomechanical response of this rock to waste emplacement. This report presents the results of a first series of calculations aimed at estimating the far-field response of argillite to waste emplacement. Because the thermal and mechanical properties of argillite are affected by its content of expandable clay, its behavior is briefly compared and contrasted with that of a shale having the same matrix thermal properties, but containing no expandable clay. Under this assumption, modeled temperatures are the same for the two rock types at equivalent power densities and reflect the large dependence of in-situ temperatures on both initial power density and waste type. Thermomechanical calculations indicate that inclusion of contraction behavior of expandable clays in the assumed argillite thermal expansion behavior results, in some cases, in generation of a large zone in and near the repository that has undergone volumetric contraction but is surrounded by uniformly compressive stresses. Information available to date indicates that this contraction would likely result in locally increased fluid permeability and decreased in-situ thermal conductivity, but might well be advantageous as regards radionuclide retention, because of the increased surface area within the contracted zone. Assumption of continuous and positive expansion behavior for the shale eliminates the near-repository contraction and tensional zones, but results in near-surface tensional zones directly above the repository

Disposal of low- and intermediate-level solid radioactive wastes in rock cavities

International Nuclear Information System (INIS)

1983-01-01

This Guidebook summarizes the factors to be considered and the activities to be undertaken in the overall planning and development of a disposal system for solid or solidified low- and intermediate-level wastes in rock cavities. Aspects related to repository site selection, design, construction, operation, shutdown, surveillance, regulation and safety assessment are discussed here in general terms. They will be covered in greater technical detail in a separate document. This report considers the emplacement of wastes in categories II, III, IV and V, as defined in Table 3.1, in different kinds of cavities located at various depths from just below the surface to deep continental rock. The choice of the type of cavity and its depth and of the disposal site itself is related to the radiological protection requirements for the wastes concerned. The repositories considered include natural caves and abandoned mines as well as specially excavated cavities in various geological formations. Consideration is also given to hydrogeological, environmental and societal factors. The guidelines given in the report are made sufficiently general to cover a broad variety of different circumstances. Consequently, the practical application of these guidelines needs a case-by-case consideration which takes into account the local conditions, e.g. natural circumstances, the characteristics of the wastes and national and international regulations and practices

A numerical study on the structural behavior of underground rock caverns for radioactive waste disposal

International Nuclear Information System (INIS)

Kim, Sun Hoon; Choi, Kyu Sup; Lee, Kyung Jin; Kim, Dae Hong

1991-01-01

In order to design safe and economical underground disposal structures for radioactive wastes, understanding the behavior of discontinuous rock masses is essential. This study includes discussions about the computational model for discontinuous rock masses and the structural analysis method for underground storage structures. Then, based on an engineering judgement a suitable selection and slight modifications on computational models and analysis methods have been made in order to analyze and understand the structural behavior of the rock cavern with discontinuities

Microstructural variation of vitrified floor tile incorporated with granitic rock waste; Variacao microestrutural de piso ceramico vitrificado incorporado com residuos de rocha granitica

Energy Technology Data Exchange (ETDEWEB)

Souza, A.J.; Holanda, J.N.F., E-mail: ajsouza@uenf.b [Universidade Estadual do Norte Fluminense Darcy Ribeiro (LAMAV/CCT/UENF), Campos dos Goytacazes, RJ (Brazil). Lab. de Materiais Avancados. Grupo de Materiais Ceramicos

2009-07-01

The ornamental rock industry from Northwest Fluminense generates huge amounts of wastes in the form of a fine powder. These wastes are deposited in nature without any care about environmental degradation, which can cause damage to public health, pollution of the natural water sources, and silted banks of rivers. In addition, they also can to affect the landscape aesthetically. In this work was used a granitic rock waste from Santo Antonio de Padua-RJ. This waste is rich in alkaline oxides, which promote the formation of liquid phase and assist the densification of traditional ceramics. The ceramic bodies with up to 47.5% granitic rock waste were pressed at 50 MPa. The ceramic pieces were fired at 1250 deg C. The evolution of sintered microstructure was evaluated by scanning electron microscopy and X-ray diffraction. The results showed that the granitic rock waste influences significantly the microstructure of the sintered ceramic bodies. (author)

Role of rock texture and mineralogy on the hydrology and geochemistry of three neutral-drainage mesoscale experimental waste rock piles at the Antamina Mine, Peru

Science.gov (United States)

Peterson, H.; Bay, D. S.; Beckie, R. D.; Mayer, K. U.; Klein, B.; Smith, L.

2009-12-01

An ongoing study at the Antamina Cu-Zn-Mo mine in Peru investigates the hydrology and geochemistry of heterogeneous waste rock at multiple scales. Three of five instrumented mesoscale experimental waste rock piles (36m X 36m X 10m high) were constructed between 2006 and 2008. The coarsest-grained Pile 1 exhibits rapid, intense response to rain and returns to residual saturation relatively quickly, suggesting a significant influence of preferential flow in addition to high-conductivity matrix flow. Pile 2, the finest-grained of the three piles, exhibits signals from rain events that are significantly delayed and muted in comparison to those from Pile 1. Except for in the finest size fractions, the particle size distribution of Pile 3 closely resembles that of Pile 2, yet Pile 3 responds to rain events more similarly to Pile 1 than Pile 2. The presence of large boulders in Pile 3 could facilitate preferential flow, either through surface flow effects across boulders or by contributing to the formation of unfilled void space acting as macropores at high infiltration rates. The rapid rain event response of Pile 3 could also be attributed to a silt-clay percentage that is similar to Pile 1, which is less than half of the silt-clay percentage observed in Pile 2 (i.e., ~3%, ~8.5%, and ~4% for Piles 1, 2 and 3, respectively). For each of the three piles, the pH of effluent collected from bottom lysimeters and internal pore water sampled with suction lysimeters has remained circumneutral, with notable maximum concentrations of 2.8 mg/L Zn from Pile 1, which is comprised of slightly reactive hornfels and marble waste rock; 13.4 mg/L Zn and 22.7 mg/L Mo from Pile 2, comprised of reactive intrusive waste rock; and 42.5 mg/L Zn from Pile 3, comprised of reactive exoskarn waste rock. Ongoing work includes analysis of two additional mixed-rock experimental piles, studies to investigate the role of microbes on metal release (Dockrey et al., this session), analysis of pore gas

Geochemistry of granitoid rocks from the western Superior Province: Evidence for 2- and 3-stage crustal evolution models

Science.gov (United States)

Beakhouse, G. P.; errane) are discussed.

1986-01-01

The Superior Province is divisible into subprovinces that can be classified as greenstone-tonalite, paragneiss, or batholitic terranes and are distinguished by differences in lithologic proportions, metamorphic grade, and structural style. The origin and significance of contrasting geochemical characteristics of plutonic rocks from the Winnipeg River subprovince (a batholithic terrane) and the Wabigoon subprovince (a greenstone-tonalite terrane) are discussed.

Hydrology of an abandoned uranium mine waste rock dump, Northern Territory

International Nuclear Information System (INIS)

Evans, K.G.; Moliere, D.R.; Saynor, M.J.

1999-01-01

Field studies were conducted on an abandoned, degraded uranium mine in Kakadu National Park to obtain waste rock dump runoff data to test the ability of a landform evolution model to predict gullying caused by concentrated flow. Runoff data were collected from natural rainfall events on a concentrated flow site and an overland flow erosion site on the waste rock dump at Scinto 6 mine. The data were used to fit parameters to a rainfall/runoff model using a non-linear regression package (NLFIT-DISTFW) which allows a single set of parameters to be fitted to four discharge hydrographs simultaneously. The model generally predicted peak discharge and the rising stage of the observed hydrographs well but there was some lag in the falling stage of the predicted hydrographs. Kinematic wave parameters are dependent on each other and the concentrated flow parameter set was not significantly different from the overland flow set. The infiltration parameter sets were statistically different and difference in cumulative infiltration between sites is controlled by sorptivity

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of Georgia

International Nuclear Information System (INIS)

Wenner, D.B.; Gillon, K.A.

1980-10-01

A literature study was conducted on the Piedmont province of Georgia to designate areas that may be favorable for field exploration for consideration of a repository for storage of radioactive waste. The criteria utilized in such a designation was based upon consideration of the rock unit having favorable geological, geotechnical, and geohydrological features. The most important are that the rock unit have: (1) satisfactory unit dimensions (> 100 km 2 outcrop area and at least 1500 meters (approx. 5000 feet) depth of a continuous rock type); and (2) acceptable geohydrological conditions. Among all rock types, it is concluded that the granites of the large post-metamorphic plutons and large, homogeneous orthogneissic units offer the most favorable geologic settings for exploration for siting a radioactive waste repository. Virtually all other rock types, including most metavolcanic and metasedimentary lithologies have unacceptable unit dimensions, generally unfavorable geohydrologic settings, and deleterious mechanical and physical geotechnical properties. After consideration of all major lithologies that comprise the Georgia Piedmont, the following units were deemed favorable: (1) the Elberton Pluton; (2) the Siloam Pluton; (3) the Sparta Pluton; (4) two unnamed plutons adjacent to the Snelson body of S.W. Georgia; (5) the Lithonia Gneiss; (6) basement orthogneisses and charnockites of the Pine Mountain Belt

Effects of bacterial action on waste rock producing acid drainage in the Brazilian first uranium mine

International Nuclear Information System (INIS)

Rey-Silva, Daniela V.F.M.; Oliveira, Alexandre P. de; Geraldo, Bianca; Campos, Michele B.; Azevedo, Heliana de; Barreto, Rodrigo P.; Souza-Santos, Marcio L. de

2009-01-01

This work is an evolution of the methodology showed in the paper 'Study of waste of waste rock piles producing acid drainage in the Brazilian first uranium mine', also submitted for INAC2009. Therefore, the present work also related to the determination of chemical species leaching from waste rock pile 4 (WRP4) of the Uranium Mine and Milling Facility located in the Pocos de Caldas Plateau, as well as the generation of acid waters. With the previous experimental setup, it has been observed that not only water and available oxygen are significant to pyrite oxidation reaction, but bacterial activity as well. As a first approach, the present work addresses the same experiment, but now testing without the influence of bacterial action. Therefore, the new methodology and experimental setup is now capable of determining the acidity of water in contact with material from the WRP4 and the concentration of chemical species dissolved as function of time. Such would also show the extent of bacterial action interference on the pyrite oxidation reaction. Results are based on mass balances comparing concentrations of chemical species in the waste rock before the experiment and in the waste rock plus the remaining water after the experiment. In addition, the evolution of the pH and EMF (electromotive force) values along with chemical species quantified through the experiment are presented through graphics. That is followed by discussions on the significance of such results in terms of concentration of the involved chemical species. The present work has also shown the need of improving the injection of air into the system. A more sophisticated experimental setup should be assembled in the near future, which would allow the quantification of differences between experimental tests with and without bacterial action. (author)

Environmental impacts of waste produced from processing of different uraniferous rock samples

Directory of Open Access Journals (Sweden)

Ibrahim E. El Aassy

2016-07-01

Full Text Available Radon exhalation rates from five studied laboratory waste samples resulted from five different sedimentary rock types named sandy dolostone, siltstone –two samples-, marly claystone and black shale were measured using ‘‘Sealed Can technique”. These rates were found to vary between 0.005 and 0.015 Bq m−2 h−1. A positive correlation was found between the radon exhalation rates and the radium activities. The emanation coefficients were calculated for these laboratory waste samples which varied between 0.0004 and 0.0007 according to the physical and chemical characterize of the wastes. These results are partially in accordance with autonite acid leached tailings on laboratory scale (USA. These results led us to pay attention about the effect and impact of these wastes on the environment.

Acidic Microenvironments in Waste Rock Characterized by Neutral Drainage: Bacteria–Mineral Interactions at Sulfide Surfaces

Directory of Open Access Journals (Sweden)

John W. Dockrey

2014-03-01

Full Text Available Microbial populations and microbe-mineral interactions were examined in waste rock characterized by neutral rock drainage (NRD. Samples of three primary sulfide-bearing waste rock types (i.e., marble-hornfels, intrusive, exoskarn were collected from field-scale experiments at the Antamina Cu–Zn–Mo mine, Peru. Microbial communities within all samples were dominated by neutrophilic thiosulfate oxidizing bacteria. However, acidophilic iron and sulfur oxidizers were present within intrusive waste rock characterized by bulk circumneutral pH drainage. The extensive development of microbially colonized porous Fe(III (oxyhydroxide and Fe(III (oxyhydroxysulfate precipitates was observed at sulfide-mineral surfaces during examination by field emission-scanning electron microscopy-energy dispersive X-ray spectroscopy (FE-SEM-EDS. Linear combination fitting of bulk extended X-ray absorption fine structure (EXAFS spectra for these precipitates indicated they were composed of schwertmannite [Fe8O8(OH6–4.5(SO41–1.75], lepidocrocite [γ-FeO(OH] and K-jarosite [KFe3(OH6(SO42]. The presence of schwertmannite and K-jarosite is indicative of the development of localized acidic microenvironments at sulfide-mineral surfaces. Extensive bacterial colonization of this porous layer and pitting of underlying sulfide-mineral surfaces suggests that acidic microenvironments can play an important role in sulfide-mineral oxidation under bulk circumneutral pH conditions. These findings have important implications for water quality management in NRD settings.

Close-out of open pit and waste rock piles of a uranium mine in Guangxi province of China

International Nuclear Information System (INIS)

Xu Lechang; Zhang Zhao; Zhang Guopu; Liu Min

2012-01-01

Close-out of projects of a mine in Guangxi province of China includes open pit,east and west waste rock piles, ore transfer station, industrial fields, buildings, ore transporting road, and equipment and conduits. The following remediation limits are introduced: environment penetrating radiation dose rate and 222 Rn flux of open pit and waste rock piles, 226 Ra specific activity of soil and individual dose. Remediation objective and programme are discussed in details. Remediation effects are evaluated. (authors)

A study of radon emanation from waste rock at Northern Territory uranium mines

International Nuclear Information System (INIS)

Mason, G.C.; Gan, T.H.; Elliott, G.

1983-01-01

Field measurements were made of radon emanation rates from waste rock sources at Ranger, Nabarlek and Rum Jungle, three Northern Territory uranium mine sites. The preliminary mean emanation rate was approximately 50 Bq m - 2 s - 2 per percent ore grade

Reclamation of waste rock material at the Summitville Mine Superfund site using organic matter and topsoil treatments

Energy Technology Data Exchange (ETDEWEB)

Winter, M.E.; Redente, E.F.

1999-07-01

The Summitville Mine was a high elevation (3,500 m) open-pit gold mine located in southwestern Colorado. The mine was abandoned in 1992 leaving approximately 200 ha of disturbed area comprised partially of two large waste rock piles. Reclamation of waste rock material is challenging due to extreme climatic conditions in conjunction with a high acid-production potential and low organic matter concentration of the material. In addition, stockpiled topsoil at the site is acidic and may be biologically inactive due to long-term storage, and therefore sufficient plant growth medium may be limited. The purpose of this study was to determine the effect of organic amendments (mushroom compost vs. biosolids) and topsoil (stockpiled vs. nonstockpiled) on aboveground biomass, herbaceous cover, and trace element uptake. An on-site field study was established in 1995 to identify the most effective combination of treatments for successful reclamation of waste rock material. Incorporation of organic matter increased total aboveground production and cover, with mushroom compost being more effective than biosolids, but did not show significant trends relative to trace element uptake. The use of topsoil did not show a significant response relative to aboveground production, cover, and trace element uptake. This study shows that waste rock materials can be directly revegetated if properly neutralized, fertilized, and amended with organic matter. Additionally, stockpiled topsoil was equivalent in plant growth to non-stockpiled topsoil when neutralized with lime.

STAFAN, Fluid Flow, Mechanical Stress in Fractured Rock of Nuclear Waste Repository

International Nuclear Information System (INIS)

Huyakorn, P.; Golis, M.J.

1989-01-01

1 - Description of program or function: STAFAN (Stress And Flow Analysis) is a two-dimensional, finite-element code designed to model fluid flow and the interaction of fluid pressure and mechanical stresses in a fractured rock surrounding a nuclear waste repository. STAFAN considers flow behavior of a deformable fractured system with fracture-porous matrix interactions, the coupling effects of fluid pressure and mechanical stresses in a medium containing discrete joints, and the inelastic response of the individual joints of the rock mass subject to the combined fluid pressure and mechanical loading. 2 - Restrictions on the complexity of the problem: STAFAN does not presently contain thermal coupling, and it is unable to simulate inelastic deformation of the rock mass and variably saturated or two-phase flow in the fractured porous medium system

Preliminary analysis of the potential for thermally-induced rock fracture around high-level waste containers

International Nuclear Information System (INIS)

Ratigan, J.L.

1976-01-01

The major results are: the development of parametric formulations relating the potential for thermally induced fracturing in the high-level radioactive waste repository concept to the elastic and thermal properties of the site rock and the depth of the excavation, and the recognition of a need to determine the actual ''failure envelope'' for any potential site rock in the laboratory and adjust the parametric relations appropriately. Analysis of five rock types indicated that none would experience elastic/brittle failure due to the thermal stresses induced by the introduction of a 5 kW heat source. However, the rock strengths and elastic properties are laboratory values and not in situ values

Rock engineering in Finland

Energy Technology Data Exchange (ETDEWEB)

1986-01-01

Contains a large collection of short articles concerned with tunnels and underground caverns and their construction and use. The articles are grouped under the following headings: use of the subsurface space; water supply; waste water services; energy management (includes articles on power stations, district heating and oil storage and an article on coal storage); multipurpose tunnels; waste disposal; transport; shelters; sporting and recreational amenities located in rock caverns; storage facilities; industrial, laboratory, and service facilities; rock foundations; tourism and culture; utilization of rock masses; research on the disposal of nuclear waste; training and research in the field of rock engineering; site investigation techniques; design of structures in rock; construction; the environment and occupational safety; modern equipment technology; underground space in Helsinki.

Rock mechanics issues and research needs in the disposal of wastes in hydraulic fractures

International Nuclear Information System (INIS)

Doe, T.W.; McClain, W.C.

1984-07-01

The proposed rock mechanics studies outlined in this document are designed to answer the basic questions concerning hydraulic fracturing for waste disposal. These questions are: (1) how can containment be assured for Oak Ridge or other sites; and (2) what is the capacity of a site. The suggested rock mechanics program consists of four major tasks: (1) numerical modeling, (2) laboratory testing, (3) field testing, and (4) monitoring. These tasks are described

Solute transport in fractured rock - applications to radionuclide waste repositories

International Nuclear Information System (INIS)

Neretnieks, I.

1990-12-01

Flow and solute transport in fractured rocks has been intensively studied in the last decade. The increased interest is mainly due to the plans in many countries to site repositories for high level nuclear waste in deep geologic formations. All investigated crystalline rocks have been found to be fractured and most of the water flows in the fractures and fracture zones. The water transports dissolved species and radionuclides. It is thus of interest to be able to understand and to do predictive modelling of the flowrate of water, the flowpaths and the residence times of the water and of the nuclides. The dissolved species including the nuclides will interact with the surrounding rock in different ways and will in many cases be strongly retarded relative to the water velocity. Ionic species may be ion exchanged or sorbed in the mineral surfaces. Charges and neutral species may diffuse into the stagnant waters in the rock matrix and thus be withdrawn from the mobile water. These effects will be strongly dependent on how much rock surface is in contact with the flowing water. It has been found in a set of field experiments and by other observations that not all fractures conduct water. Furthermore it is found that conductive fractures only conduct the water in a small part of the fracture in what is called channels or preferential flowpaths. This report summarizes the present concepts of water flow and solute transport in fractured rocks. The data needs for predictive modelling are discussed and both field and laboratory measurement which have been used to obtain data are described. Several large scale field experiments which have been specially designed to study flow and tracer transport in crystalline rocks are described. In many of the field experients new techniques have been developed and used. (81 refs.) (author)

Initial assessment of the thermal stresses around a radioactive waste depository in hard rock

International Nuclear Information System (INIS)

Hodgkinson, D.P.; Bourke, P.J.

1980-01-01

The disposal of heat emitting radioactive waste into hard rock should result in temperature rises and thermal gradients over distances of several hundred metres for several centuries. The consequent constrained thermal expansion of the rock would induce stresses which have important implications for possible water-borne leakage of radionuclides and for depository design. These problems are assessed by considering a simplified mathematical model for which analytic solutions to the temperature and stress fields are derived. (author)

Technical support for GEIS: radioactive waste isolation in geologic formations. Volume 6. Baseline rock properties-shale

International Nuclear Information System (INIS)

1978-04-01

This volume, Y/OWI/TM36/6 Baseline Rock Properties--Shale, is one of a 23-volume series, ''Technical Support for GEIS: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-36'' which supplements a ''Contribution to Draft Generic Environmental Impact Statement on Commercial Waste Management: Radioactive Waste Isolation in Geologic Formations, Y/OWI/TM-44.'' The series provides a more complete technical basis for the preconceptual designs, resource requirements, and environmental source terms associated with isolating commercial LWR wastes in underground repositories in salt, granite, shale and basalt. Wastes are considered from three fuel cycles: uranium and plutonium recycling, no recycling of spent fuel and uranium-only recycling. The report is a result of a literature survey of the rock properties of shales occurring in the United States. Firstly, data were collected from a wide variety of sources in order to obtain a feel for the range of properties encountered. Secondly, some typical shales were selected for detailed review and these are written up as separate chapters in this report. Owing to the wide variability in lithology and properties of shales occurring in the United States, it became necessary to focus the study on consolidated illite shales. Using the specific information already generated, a consistent set of intact properties for a typical, consolidated illite shale was obtained. Correction factors, largely based on geological considerations, were then applied to the intact data in order to yield typical rock mass properties for this type of shale. Lastly, excavation problems in shale formations were reviewed and three tunnel jobs were written up as case histories

The disposal of radioactive wastes in Brazil with special emphasis on rocks

International Nuclear Information System (INIS)

Enokihara, Cyro Teiti

1983-01-01

The disposal of radioactive wastes in geological formations seems to be the most appropriate solution for the nuclear waste problem. The disposal sites must provide the maximum safety for the radionuclides during its decay period. The study presents a general analysis of three types rocks: salt, granite and basalt. In our analysis we have dealt with the following aspects: geology, tectonics, seismicity, hydrogeology , mineral resources, geomorphology, population and access. The studied regions were: Sergipe-Alagoas and Reconcavo Basins, Northeastern and Southeastern Folded Regions and Parana Basin. Our study contains the macro-analysis needed for the selection of a safe site for radioactive waste disposal. We believe this work will be useful as a first step for further micro-analysis of selected sites. (author)

Thermal Analysis of a Nuclear Waste Repository in Argillite Host Rock

Science.gov (United States)

Hadgu, T.; Gomez, S. P.; Matteo, E. N.

2017-12-01

Disposal of high-level nuclear waste in a geological repository requires analysis of heat distribution as a result of decay heat. Such an analysis supports design of repository layout to define repository footprint as well as provide information of importance to overall design. The analysis is also used in the study of potential migration of radionuclides to the accessible environment. In this study, thermal analysis for high-level waste and spent nuclear fuel in a generic repository in argillite host rock is presented. The thermal analysis utilized both semi-analytical and numerical modeling in the near field of a repository. The semi-analytical method looks at heat transport by conduction in the repository and surroundings. The results of the simulation method are temperature histories at selected radial distances from the waste package. A 3-D thermal-hydrologic numerical model was also conducted to study fluid and heat distribution in the near field. The thermal analysis assumed a generic geological repository at 500 m depth. For the semi-analytical method, a backfilled closed repository was assumed with basic design and material properties. For the thermal-hydrologic numerical method, a repository layout with disposal in horizontal boreholes was assumed. The 3-D modeling domain covers a limited portion of the repository footprint to enable a detailed thermal analysis. A highly refined unstructured mesh was used with increased discretization near heat sources and at intersections of different materials. All simulations considered different parameter values for properties of components of the engineered barrier system (i.e. buffer, disturbed rock zone and the host rock), and different surface storage times. Results of the different modeling cases are presented and include temperature and fluid flow profiles in the near field at different simulation times. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and

Geotechnical core and rock mass characterization for the UK radioactive waste repository design

International Nuclear Information System (INIS)

Rawlings, C.G.; Barton, N.; Loset, F.; Vik, G.; Bhasin, R.K.; Smallwood, A.; Davies, N.

1996-01-01

The NGI method of characterizing joints (using JRC, JCS and φ r ) and characterizing rock masses (using the Q-system) have been and are currently being used extensively in geotechnical consultancy projects. One such project recently completed for UK Nirex Ltd included the logging of 8 km of 100-mm-diameter drill core from boreholes up to 2km in depth. Preliminary rock reinforcement designs were derived from the Q-system statistics, which were logged in parallel with JRC, JCS and φ r . The data from the NGI method of characterizing joints and the Q-system for characterizing rock masses have also been used as the basis for UDEC-BB numerical modelling of the proposed cavern excavations for the disposal of solid, low- and intermediate-level radioactive wastes. The purpose of this numerical modelling was to investigate the stability of rock caverns and in particular the rock reinforcement requirements (giving predicted bolt loads and rock deformations), the extent of the disturbed zone (joint shearing and hydraulic aperture) with respect to cavern orientation, the effect of various pillar widths, and the effect of the cavern excavation sequence. (Author)

Radionuclide transport in fractured rock: quantifying releases from final disposal of high level waste

International Nuclear Information System (INIS)

Silveira, Claudia S. da; Alvim, Antonio C.M.

2013-01-01

Crystalline rock has been considered as a potentially suitable matrix for high-level radioactive waste (HLW) repository because it is found in very stable geological formations and may have very low permeability. In this study the adopted physical system consists of the rock matrix containing a discrete horizontal fracture in a water saturated porous rock and a system of vertical fractures as a lineament. The transport in the fractures - horizontal and vertical, is assumed to obey a relation convection-diffusion, while the molecular diffusion is considered dominant mechanism of transport in porous rock. In this model the decay chain is considered. We use a code in Fortran 90, where the partial differential equations that describe the movement of radionuclides were discretized by finite differences methods. We use the fully implicit method for temporal discretization schemes. The simulation was performed with relevant data of nuclides in spent fuel for performance assessment in a hypothetical repository, thus quantifying the radionuclides released into the host rock. (author)

Influence of convective-energy transfer on calculated temperature distributions in proposed hard-rock nuclear waste repositories

Energy Technology Data Exchange (ETDEWEB)

Eaton, R R; Reda, D C [Sandia National Labs., Albuquerque, NM (USA)

1982-06-01

This study assesses the relative influence of convective-energy transfer on predicted temperature distributions for a nuclear-waste repository located in water-saturated rock. Using results for energy transfer by conduction only (no water motion) as a basis of comparison, it is shown that a considerable amount of energy can be removed from the repository by pumping out water that migrates into the drift from regions adjacent to the buried waste canisters. Furthermore, the results show that the influence of convective-energy transfer on mine drift cooling requirements can be significant for cases where the in-situ permeability of the rock is greater than one millidarcy (a regime potentially encountered in repository scenarios).

A case study of long-term geochemical evolution of coal waste rock drainage and its remediation

Energy Technology Data Exchange (ETDEWEB)

Jarvis, A.P.; Gandy, C.J. [Newcastle Univ. (United Kingdom). School of Civil Engineering and Geosciences, Hydrogeochemical Engineering Research and Outreach Group

2010-07-01

The geochemical evolution of drainage from an 35 hectare orphan waste rock pile over a 15-year period was described. Spoil material at the site was generated during coal mining at 2 collieries between 1922 and 1970, and was comprised of grey and black shale, ash, coal, and coal dust. The heap was founded on an impermeable clay layer. Located in northern England, drainage from the rock heap was intercepted by a small compost wetland system installed in 1997. The waste rock heap was selectively capped in 1998. Water samples were collected and analyzed. Anion concentrations were determined using an ion chromatograph. The samples were filtered periodically. Acidity concentrations and flow rates were determined. Results of the study showed measurable improvements in water quality as a result of capping the heap. The study demonstrated that a combination of selective spoil capping and wetland treatment can serve as a low-cost solution to acid mine drainage at some abandoned mine sites. 9 refs., 1 tab., 1 fig.

A case study of long-term geochemical evolution of coal waste rock drainage and its remediation

International Nuclear Information System (INIS)

Jarvis, A.P.; Gandy, C.J.

2010-01-01

The geochemical evolution of drainage from an 35 hectare orphan waste rock pile over a 15-year period was described. Spoil material at the site was generated during coal mining at 2 collieries between 1922 and 1970, and was comprised of grey and black shale, ash, coal, and coal dust. The heap was founded on an impermeable clay layer. Located in northern England, drainage from the rock heap was intercepted by a small compost wetland system installed in 1997. The waste rock heap was selectively capped in 1998. Water samples were collected and analyzed. Anion concentrations were determined using an ion chromatograph. The samples were filtered periodically. Acidity concentrations and flow rates were determined. Results of the study showed measurable improvements in water quality as a result of capping the heap. The study demonstrated that a combination of selective spoil capping and wetland treatment can serve as a low-cost solution to acid mine drainage at some abandoned mine sites. 9 refs., 1 tab., 1 fig.

A study on nuclide migration in buffer materials and rocks for geological disposal of radioactive waste

International Nuclear Information System (INIS)

Sato, Haruo

1998-01-01

This thesis summarizes the results investigated in order to establish a basic theory on the predictive method of diffusion coefficients of nuclides in compacted sodium bentonite which is a candidate buffer material and in representative rocks for the geological disposal of radioactive waste by measuring the pore structural factors of the compacted bentonite and rocks such as porosity and tortuosity, measuring diffusion coefficients of nuclides in the bentonite and rocks, acquiring basic data on diffusion and developing diffusion models which can quantitatively predict nuclide migration in long-term. (J.P.N.). 117 refs

Repository for high level radioactive wastes in Brazil: the importance of geochemical (Micro thermometric) studies and fluid migration in potential host rocks

International Nuclear Information System (INIS)

Rios, Francisco Javier; Fuzikawa, Kazuo; Alves, James Vieira; Neves, Jose Marques Correia

2003-01-01

A detailed fluid inclusion study of host rocks, is of fundamental importance in the selection of geologically suitable areas for high level nuclear waste repository constructions (HLRW). The LIFM-CDTN is enabled to develop studies that confirm: the presence or not, of corrosive fluid in minerals from host rocks of the repository and the possible presence of micro fractures (and fluid leakage) when these rocks are submitted to high temperatures. These fluid geochemistry studies, with permeability determinations by means of pressurized air injection must be carried out in rocks hosting nuclear waste. Micro fracture determination is of vital importance since many naturally corrosive solutions, present in the mineral rocks, could flow out through these plans affecting the walls of the repository. (author)

Disposal of low- and intermediate-level solid radioactive wastes in rock cavities. A guidebook

Energy Technology Data Exchange (ETDEWEB)

1983-01-01

This Guidebook summarizes the factors to be considered and the activities to be undertaken in the overall planning and development of a disposal system for solid or solidified low- and intermediate-level wastes in rock cavities. Aspects related to repository site selection, design, construction, operation, shutdown, surveillance, regulation and safety assessment are discussed here in general terms. They will be covered in greater technical detail in a separate document. This report considers the emplacement of wastes in categories II, III, IV and V, as defined in Table 3.1, in different kinds of cavities located at various depths from just below the surface to deep continental rock. The choice of the type of cavity and its depth and of the disposal site itself is related to the radiological protection requirements for the wastes concerned. The repositories considered include natural caves and abandoned mines as well as specially excavated cavities in various geological formations. Consideration is also given to hydrogeological, environmental and societal factors. The guidelines given in the report are made sufficiently general to cover a broad variety of different circumstances. Consequently, the practical application of these guidelines needs a case-by-case consideration which takes into account the local conditions, e.g. natural circumstances, the characteristics of the wastes and national and international regulations and practices.

Hydrogeochemical assessment of crystaline rock for radioactive waste disposal: the Stripa experience

International Nuclear Information System (INIS)

Andrews, J.; Fontes, J.C.; Fritz, P.; Nordstroem, K.

1988-08-01

This report presents a program for the hydro-geochemical assessment of a crystalline rock site for radioactive waste disposal. It is based upon experience gained during the international program of hydrochemical work at the Stripa mine. The important result of this work are summarized in this report and fuller details may be found in the separate final reports of the Phase 1 and Phase 2 geochemical investigations of the Stripa groundwaters. The present report summarizes the general sampling requirements for a successful hydrochecmical investigation; the isotopic and chemical parameters which should be determined an the geochemical characterization of the rock matrix necessary for the interpretation of hydrochemistry. A general strategy for site evaluation by geochemical methods is presented. (authors)

Geological disposal of high-level radioactive waste and the role of rock engineering

International Nuclear Information System (INIS)

Sugihara, Kozo

2008-01-01

Japan Atomic Energy Agency (JAEA) and its predecessors have been conducting an extensive geoscientific research program since the 1970's in order to contribute to the formation of a firm scientific and technological basis for the geological disposal of high level radioactive waste in Japan. As a part of this program, in situ experiments have been performed at the Tono Mine in soft sedimentary rocks and at the Kamaishi Mine in hard crystalline rocks. An experiment on excavation disturbance has been one of these experiments and has revealed the extent and properties of the excavation disturbed zone (EDZ) and the applicability of available measurement methods. It is suggested that mechanical excavation and controlled excavation have reduced excavation damage of the rock mass around a drift, although some improvements in the currently available methods for measuring and simulating the EDZ are essential to understand excavation disturbance in more detail. JAEA is now promoting two underground research laboratory projects in Japan; the Mizunami Underground Research Laboratory (MIU) project for crystalline rocks and the Horonobe Underground Research Laboratory (Horonobe URL) project for sedimentary rocks. From a rock mechanical point of view, the major interest in these projects will be paid to failure phenomenon deep underground, rock stress estimation at larger scales and long-term physical stability of underground structure. These projects are open for international collaboration. (author)

Geotechnical assessment and instrumentation needs for isolation of nuclear waste in crystalline rocks: symposium proceedings

International Nuclear Information System (INIS)

Ubbes, W.F.; Duguid, J.O.

1985-09-01

On October 15-19, 1984, the Geotechnical Assessment and Instrumentation Needs (GAIN) Symposium was convened to examine the status of technology for the isolation of nuclear waste in crystalline rock. The objective of the 1984 GAIN Symposium was to provide technical input to the Crystalline Repository Project concerning: critical issues and information needs associated with development and assessment of a repository in crystalline rock; appropriate techniques and instrumentation for determining the information needed; and technology required to provide the measurement techniques and instrumentation for application in an exploratory shaft in crystalline rock. The findings and recommendations of the symposium are presented in these proceedings

Gabbro as a host rock for a nuclear waste repository

International Nuclear Information System (INIS)

Ahlbom, K.; Leijon, B.; Smellie, J.; Liedholm, M.

1992-09-01

As an alternative to granitic rocks, gabbro and other basic rock types have been investigated with respect to their suitability to host a nuclear waste repository. The present report summarizes and examines existing geoscientific knowledge of relevance in assessing the potential merits of gabbro as a repository host rock. Implications in terms of site selection, repository construction and post-closure repository performance are also discussed. The objective of the study is to provide a basis for decisions as regards future consideration of the gabbro alternative. It is found that there are rather few gabbro bodies in Sweden, that are potentially of sufficient size to host a repository. Thus, gabbro offers little latitude as regards site selection. In comparison to siting a repository in granitic rocks, this is a major disadvantage, and it may in fact remove gabbro from further consideration. The potential advantages of gabbro refer to repository performance, and include low hydraulic conductivity and a chemical environment promoting efficient radionuclide retardation. However, results from field investigations show that groundwater flow in gabbro bodies is largely controlled by intersecting heterogeneities, in particular granitic dykes, that are significantly more conductive to water than the gabbro. In the far-field scale significant to repository performance, this may reduce or eliminate the potential effects of favourable hydraulic and chemical characteristics of the gabbro itself. In conclusion, there are apparent difficulties associated with siting a repository in gabbro, due to lack of sufficiently large gabbro bodies. On the basis of the present state of knowledge, no decisive differences can be demonstrated when comparing gabbro with granitic rocks, neither with respects to repository construction, nor as regards repository performance. (au)

Technology needs for selecting and evaluating high-level waste repository sites in crystalline rock

International Nuclear Information System (INIS)

1988-12-01

This report describes properties and processes that govern the performance of the geological barrier in a nuclear waste isolation system in crystalline rock and the state-of-the-art in the understanding of these properties and processes. Areas and topics that require further research and development as well as technology needs for investigating and selecting repository sites are presented. Experiences from the Swedish site selection program are discussed, and a general investigation strategy is presented for an area characterization phase of an exploratory program in crystalline rocks. 255 refs., 65 figs., 10 tabs

Transient diffusion from a waste solid into water-saturated, fractured porous rock

International Nuclear Information System (INIS)

Ahn, J.; Chambre, P.L.; Pigford, T.H.; Lee, W.W.-L.

1989-09-01

Numerical illustrations for transient mass transfer from an infinitely long cylinder intersected by a planar fracture are shown based on Chambre's exact analytical solutions. The concentration at the cylinder surface is maintained at the solubility. In the fracture contaminant diffuses in the radial direction. In the rock matrix three-dimensional diffusion is assumed in the cylindrical coordinate. No advection is assumed. Radioactive decay and sorption equilibrium are included. Radioactive decay enhances the mass transfer from the cylinder. Due to the presence of the fracture, the mass flux from the cylinder to the rock matrix becomes smaller, but the fracture effect is limited in the vicinity of the fracture in early times. Even though the fracture is assumed to be a faster diffusion path than the rock matrix, the larger waste surface exposed to the matrix and the greater assumed matrix sorption result in greater release rate to the matrix than to the fracture. 8 refs., 4 figs

A feasibility study to determine the functionality of a novel rocking kiln - fluidized bed reactor for the treatment of waste

International Nuclear Information System (INIS)

Mohamad Azman Che Mat Isa; Muhd Noor Muhd Yunus; Mohamad Puad Abu; Shahazrin Mohd Nasir; Mohd fairus Abdul Farid

2004-01-01

Rotary kiln has been widely used in incineration and studied by many researches. Solid wastes of various shapes, sizes and heat value can be fed into rotary kiln either in batches or continually. Waste combustion in rotary kiln involves rotation method and the residence time depends on the length and diameter of the rotary kiln and the total stoichiometric air given to the system. Rocking system is another technology used in incinerator. In the rocking system, internal elements in the combustion chamber move to transports and mix the burning waste so that all combustible material in the waste is fully burnt. Another technology in incinerator is the fluidized bed This method uses air to fluidized the sand thus enhancing the combustion process. The total air is controlled in order to obtain a suitable fluidized condition This preliminary study was conducted to study the feasibility of an incinerator system when three components viz. the rotary kiln, rocking system and fluidized bed are combined This research was also conducted to obtain preliminary data parameters of the three components such as the suitable temperature, the angle of the kiln, residence time, total air for fluidization, rocking speed and the devolatilization rate. The samples used in this research were the palm oil kernel shells. The results of the studies showed that the palm oil kernel shells combusted evenly using the new parameters. (Author)

Preparation of soda-lime glass using rock wool waste; Preparacao de vidros sodo-calcicos utilizando residuo de la de rocha

Energy Technology Data Exchange (ETDEWEB)

Aleixo, F.C.; Della, V.P. [Instituto Federal do Espirito Santo, Vitoria, ES (Brazil); Ballmann, T.J.S.; Folgueras, M.V. [Universidade do Estado de Santa Catarina (UESC), Joinville, SC (Brazil); Junkes, J.A., E-mail: janajunkes@gmail.com [Centro Universitario Tiradentes, Maceio, AL (Brazil)

2016-10-15

Discarded by the mining industry during the maintenance stoppages of pelletizing furnaces, rock wool has in its composition SiO{sub 2} (56%), Na{sub 2} O (12%) and CaO (7%) propitious for obtaining soda-lime glasses. Under this focus, this work developed soda-lime glasses formulations, using as main raw-material rock wool waste in proportions from 50 to 100% by adjusting the chemical composition of the formulations with sand, sodium and calcium carbonates, as silica, soda and lime sources, respectively. In some formulations the sodium carbonate was replaced by sodium sulfate, which acts as a refining agent, improving homogenization and reducing the bubble formation during the melting. Initially, the raw-materials were evaluated by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and thermogravimetric analysis. The tests showed that the rock wool waste has potential to be used in soda-lime glasses production, however, the chemical composition must be corrected. After knowing the waste potential, seven mixtures were prepared and molten at 1550 °C for 1 to 2 h. It has been found that the maximum rock wool waste percentage that can be used is between 60 and 80%, and that the 2 h melting time resulted in more homogeneous glasses and fewer bubbles according to the addition of sodium sulfate which is efficient for bubbles removal. (author)

Comparison of thermally induced and naturally occurring water-borne leakages from hard rock depositories for radioactive waste

International Nuclear Information System (INIS)

Bourke, P.J.; Robinson, P.C.

1981-01-01

The relative importance of thermally induced and naturally occurring flows of water as causes of leakage from hard rock depositories for radioactive wastes is assessed. Separate analyses are presented for involatile, high level waste from reprocessing of fuel and for plutonium contaminated waste from fabrication of fuel. The effects of varying the quantities of wastes, pre-burial storage and the shapes and depths of depositories are considered. It is concluded that for representative values of these variables, thermal flow will remain the major cause of leakage for long times after the burial of both types of waste. (Auth.)

Chemical buffering capacity of clay rock

International Nuclear Information System (INIS)

Beaucaire, C.; Pearson, F.J.; Gautschi, A.

2004-01-01

The long-term performance of a nuclear waste repository is strongly dependent on the chemical properties of the host rock. The host rock establishes the chemical environment that determines such important performance attributes as radionuclide solubilities from the waste and the transport rates from the repository to the accessible environment. Clay-rich rocks are especially favourable host rocks because they provide a strong buffering capacity to resist chemical changes prompted either internally, by reactions of the waste itself and emplacement materials, or externally, by changes in the hydrologic systems surrounding the host rock. This paper will focus on three aspects of the stability of clay-rich host rocks: their ability to provide pCO 2 and redox buffering, and to resist chemical changes imposed by changes in regional hydrology and hydro-chemistry. (authors)

Water - rock interaction in different rock environments

International Nuclear Information System (INIS)

Lamminen, S.

1995-01-01

The study assesses the groundwater geochemistry and geological environment of 44 study sites for radioactive waste disposal. Initially, the study sites were divided by rock type into 5 groups: (1) acid - intermediate rocks, (2) mafic - ultramafic rocks, (3) gabbros, amphibolites and gneisses that contain calc-silicate (skarn) rocks, (4) carbonates and (5) sandstones. Separate assessments are made of acid - intermediate plutonic rocks and of a subgroup that comprises migmatites, granite and mica gneiss. These all belong to the group of acid - intermediate rocks. Within the mafic -ultramafic rock group, a subgroup that comprises mafic - ultramafic plutonic rocks, serpentinites, mafic - ultramafic volcanic rocks and volcanic - sedimentary schists is also evaluated separately. Bedrock groundwaters are classified by their concentration of total dissolved solids as fresh, brackish, saline, strongly saline and brine-class groundwaters. (75 refs., 24 figs., 3 tabs.)

Qualitative evaluation of various models for mechanical analysis of nuclear wastes storage in brittle rocks

International Nuclear Information System (INIS)

Millard, A.

1994-01-01

In order to appraise the large scale behaviour of high level nuclear wastes underground repositories in brittle rocks, basic models are presented and evaluated in the case of generic repository configurations. Predictive Capabilities of the models are briefly discussed. 7 figs

Seismic response of rock joints and jointed rock mass

International Nuclear Information System (INIS)

Ghosh, A.; Hsiung, S.M.; Chowdhury, A.H.

1996-06-01

Long-term stability of emplacement drifts and potential near-field fluid flow resulting from coupled effects are among the concerns for safe disposal of high-level nuclear waste (HLW). A number of factors can induce drift instability or change the near-field flow patterns. Repetitive seismic loads from earthquakes and thermal loads generated by the decay of emplaced waste are two significant factors. One of two key technical uncertainties (KTU) that can potentially pose a high risk of noncompliance with the performance objectives of 10 CFR Part 60 is the prediction of thermal-mechanical (including repetitive seismic load) effects on stability of emplacement drifts and the engineered barrier system. The second KTU of concern is the prediction of thermal-mechanical-hydrological (including repetitive seismic load) effects on the host rock surrounding the engineered barrier system. The Rock Mechanics research project being conducted at the Center for Nuclear Waste Regulatory Analyses (CNWRA) is intended to address certain specific technical issues associated with these two KTUs. This research project has two major components: (i) seismic response of rock joints and a jointed rock mass and (ii) coupled thermal-mechanical-hydrological (TMH) response of a jointed rock mass surrounding the engineered barrier system (EBS). This final report summarizes the research activities concerned with the repetitive seismic load aspect of both these KTUs

The role of the disturbed rock zone in radioactive waste repository safety and performance assessment. A topical discussion and international overview

International Nuclear Information System (INIS)

Winberg, A.

1991-06-01

A discussion was presented of the role and relative importance of the disturbed rock zone (DRZ) around the underground openings of a repository for nuclear waste in crystalline rock. The term disturbed rock zone was defined and possible criteria to be sued to distinguish if from undisturbed rock was suggested. The processes decisive for the hydraulic characteristics of the DRZ were discussed. With regard to the integral hydraulic characteristics of the DRZ, the effects of the excavation methodology, stress redistribution, thermal changes, chemical changes and backfill were discussed. A review of in-situ observations of the DRZ was provided. Model analysis where the DRZ has been explicitly or implicitly represented, either from a phenomenological and performance assessment aspect were reviewed. The implications of the disturbed rock zone for the safe performance of a nuclear waste repository were discussed. Conceptual models for the geometry of the DRZ and hydraulic conductivity distribution in the DRZ were suggested. (au) (82 refs.)

Combined DC resistivity and induced polarization (DC-IP) for mapping the internal composition of a mine waste rock pile in Nova Scotia, Canada

Science.gov (United States)

Power, Christopher; Tsourlos, Panagiotis; Ramasamy, Murugan; Nivorlis, Aristeidis; Mkandawire, Martin

2018-03-01

Mine waste rock piles (WRPs) can contain sulfidic minerals whose interaction with oxygen and water can generate acid mine drainage (AMD). Thus, WRPs can be a long-term source of environmental pollution. Since the generation of AMD and its release into the environment is dependent on the net volume and bulk composition of waste rock, effective characterization of WRPs is necessary for successful remedial design and monitoring. In this study, a combined DC resistivity and induced polarization (DC-IP) approach was employed to characterize an AMD-generating WRP in the Sydney Coalfield, Nova Scotia, Canada. Two-dimensional (2D) DC-IP imaging with 6 survey lines was performed to capture the full WRP landform. 2D DC results indicated a highly heterogeneous and moderately conductive waste rock underlain by a resistive bedrock containing numerous fractures. 2D IP (chargeability) results identified several highly-chargeable regions within the waste, with normalized chargeability delineating regions specific to waste mineralogy only. Three-dimensional (3D) DC-IP imaging, using 17 parallel lines on the plateau of the pile, was then used to focus on the composition of the waste rock. The full 3D inverted DC-IP distributions were used to identify coincident and continuous zones (isosurfaces) of low resistivity (0.4 mS/m) that were inferred as generated AMD (leachate) and stored AMD (sulfides), respectively. Integrated geological, hydrogeological and geochemical data increased confidence in the geoelectrical interpretations. Knowledge on the location of potentially more reactive waste material is extremely valuable for improved long-term AMD monitoring at the WRP.

Radon emission from uranium mining waste rock dumps and resulting radon immission; Radonemissionsverhalten von Halden des Uranbergbaus und daraus resultierende Radonemissionen

Energy Technology Data Exchange (ETDEWEB)

Regner, J.; Hinz, W.; Schmidt, P. [Wismut GmbH, Chemnitz (Germany)

2016-07-01

Since more than 20 years, Wismut GmbH has been investigating the radon situation at uranium mining waste rock dumps. In the present paper the results of 19 complex studies at uranium mining dumps in the Erzgebirge (Ore Mountains) are reported. Although the mean specific activity of Ra-226 of the waste rock material was on a rather low level of about 0.5 Bq/g, the mean radon concentration in free atmosphere at the public exposure sites in the immediate vicinity of the dumps reached a value of about 1000 Bq/m{sup 3} for a half-year exposition and of about 600 Bq/m{sup 3} for a one-year exposition. Certain geometries and structures of waste rock dumps and the occurrence of convective airflows in the dumps are main reasons for the high radon emission despite of the relatively low specific Ra-226 activity. A case study for two buildings directly on the top of a waste rock dump in the town Johanngeorgenstadt is presented. The hypothetical interpolation of the results for Ra-226-activity to a value below the threshold value of 0.2 Bq/g leads to the assumption that problematic radon situations may also occur outside the areas of legacies of uranium mining. Considering the aspects mentioned, a clearance level for NORM of 1 Bq/g is questionable.

Impact of bimodal textural heterogeneity and connectivity on flow and transport through unsaturated mine waste rock

Science.gov (United States)

Appels, Willemijn M.; Ireson, Andrew M.; Barbour, S. Lee

2018-02-01

Mine waste rock dumps have highly variable flowpaths caused by contrasting textures and geometry of materials laid down during the 'plug dumping' process. Numerical experiments were conducted to investigate how these characteristics control unsaturated zone flow and transport. Hypothetical profiles of inner-lift structure were generated with multiple point statistics and populated with hydraulic parameters of a finer and coarser material. Early arrival of water and solutes at the bottom of the lifts was observed after spring snowmelt. The leaching efficiency, a measure of the proportion of a resident solute that is flushed out of the rock via infiltrating snowmelt or rainfall, was consistently high, but modified by the structure and texture of the lift. Under high rates of net percolation during snowmelt, preferential flow was generated in coarse textured part of the rock, and solutes in the fine textured parts of the rock remained stagnant. Under lower rates of net percolation during the summer and fall, finer materialswere flushed too, and the spatial variability of solute concentration in the lift was reduced. Layering of lifts leads to lower flow rates at depth, minimizing preferential flow and increased leaching of resident solutes. These findings highlight the limited role of large scale connected geometries on focusing flow and transport under dynamic surface net percolation conditions. As such, our findings agree with recent numerical results from soil studies with Gaussian connected geometries as well as recent experimental findings, emphasizing the dominant role of matrix flow and high leaching efficiency in large waste rock dumps.

Review of potential host rocks for radioactive waste disposal in the Piedmont province of North Carolina

International Nuclear Information System (INIS)

Butler, J.R.

1980-10-01

This report reviews the geology of the Piedmont province in North Carolina, emphasizing those features most pertinent to selection of potential host rocks for radioactive waste disposal. Discussion of criteria for selection indicates that the outcrop area of the rock body, probable homogeneity, low incidence of fractures, and low permeability are among the prime considerations. Application of the criteria leads to the selection of three large granite batholiths (Castalia, Churchland, and Rolesville) as potential field study areas. The report has an extensive bibliography

Rock solidification method

International Nuclear Information System (INIS)

Nakaya, Iwao; Murakami, Tadashi; Miyake, Takafumi; Funakoshi, Toshio; Inagaki, Yuzo; Hashimoto, Yasuhide.

1985-01-01

Purpose: To convert radioactive wastes into the final state for storage (artificial rocks) in a short period of time. Method: Radioactive burnable wastes such as spent papers, cloths and oils and activated carbons are burnt into ashes in a burning furnace, while radioactive liquid wastes such as liquid wastes of boric acid, exhausted cleaning water and decontaminating liquid wastes are powderized in a drying furnace or calcining furnace. These powders are joined with silicates as such as white clay, silica and glass powder and a liquid alkali such as NaOH or Ca(OH) 2 and transferred to a solidifying vessel. Then, the vessel is set to a hydrothermal reactor, heated and pressurized, then taken out about 20 min after and tightly sealed. In this way, radioactive wastes are converted through the hydrothermal reactions into aqueous rock stable for a long period of time to obtain solidification products insoluble to water and with an extremely low leaching rate. (Ikeda, J.)

Proceedings of workshop 5: Flow and transport through unsaturated fractured rock -- related to high-level radioactive waste disposal

International Nuclear Information System (INIS)

Evans, D.D.; Nicholson, T.J.

1993-06-01

The ''Workshop on Flow and Transport Through Unsaturated Fractured Rock Related to High-Level Radioactive Waste Disposal'' was cosponsored by the NRC, the Center for Nuclear Waste Regulatory Analyses, and the University of Arizona (UAZ) and was held in Tucson, Arizona, on January 7--10, 1991. The focus of this workshop, similar to the earlier four (the first being in 1982), related to hydrogeologic technical issues associated with possible disposal of commercial high-level nuclear waste (HLW) in a geologic repository within an unsaturated fractured rock system which coincides with the UAZ field studies on HLW disposal. The presentations and discussions centered on flow and transport processes and conditions, relevant parameters, as well as state-of-the-art measurement techniques, and modeling capabilities. The workshop consisted of: four half-day technical meetings, a one day field visit to the Apache Leap test site to review ongoing field studies that are examining site characterization techniques and developing data sets for model validation studies, and a final half-day session devoted to examining research needs related to modeling groundwater flow and radionuclide transport in unsaturated, fractured rock. These proceedings provide extended abstracts of the technical presentations and short summaries of the research group reports

The use of borehole geophysical logs and hydrologic tests to characterize plutonic rock for nuclear fuel waste disposal

International Nuclear Information System (INIS)

Davison, C.C.

1984-05-01

The selection of an igneous rock body for the disposal of nuclear fuel waste will likely require the drilling and testing of a number of deep investigative boreholes in the rock body. Although coring of at least one hole at each Research Area will be essential, methods for making in situ geophysical and hydrological measurements can substitute for widespread coring and result in significant savings in time and money. A number of borehole methods have been applied to the investigation of plutonic rocks at Whiteshell Nuclear Research Establishment and Chalk River Nuclear Laboratories in Canada

Numerical modeling of the geomechanical response of a rock mass to a radioactive waste repository

International Nuclear Information System (INIS)

Hardy, M.P.; St John, C.M.; Hocking, G.

1979-06-01

Geotechnical numerical models capable of predicting the thermomechanical response and groundwater movements around an underground radioactive waste repository are vital to the success of the nuclear waste disposal program. In the absence of directly related engineering experience, the design, risk assessment, and licensing procedures of a repository will be reliant on predictions made using such models. This paper reviews models being used to assist in repository design and summarizes the results of a recent parametric study of underground disposal in basaltic rocks. On the basis of preliminary site data, it is concluded that the allowable areal density of heat-generating waste will be controlled by the stability of placement rooms and the boreholes in which waste canisters are placed. Regional effects including thermally induced upward groundwater flow, appear to present less severe problems

Estimates of water and solute release from a coal waste rock dump in the Elk Valley, British Columbia, Canada.

Science.gov (United States)

Villeneuve, S A; Barbour, S L; Hendry, M J; Carey, S K

2017-12-01

Long term (1999 to 2014) flow and water quality data from a rock drain located at the base of a coal waste rock dump constructed in the Elk Valley, British Columbia was used to characterize the release of three solutes (NO 3 - , Cl - and SO 4 2- ) from the dump and obtain whole dump estimates of net percolation (NP). The concentrations of dump derived solutes in the rock drain water were diluted by snowmelt waters from the adjacent natural watershed during the spring freshet and reached a maximum concentration during the winter baseflow period. Historical peak baseflow concentrations of conservative ions (NO 3 - and Cl - ) increased until 2006/07 after which they decreased. This decrease was attributed to completion of the flushing of the first pore volume of water stored within the dump. The baseflow SO 4 2- concentrations increased proportionally with NO 3 - and Cl - to 2007, but then continued to slowly increase as NO 3 - and Cl - concentrations decreased. This was attributed to ongoing production of SO 4 2- due to oxidation of sulfide minerals within the dump. Based on partitioning of the annual volume of water discharged from the rock drain to waste rock effluent (NP) and water entering the rock drain laterally from the natural watershed, the mean NP values were estimated to be 446±50mm/a (area normalized net percolation/year) for the dump and 172±71mm/a for the natural watershed. The difference was attributed to greater rates of recharge in the dump from summer precipitation compared to the natural watershed where rainfall interception and enhanced evapotranspiration will increase water losses. These estimates included water moving through subsurface pathways. However, given the limitations in quantifying these flows the estimated NP rates for both the natural watershed and the waste rock dump are considered to be low, and could be much higher (e.g. ~450mm/a and ~800mm/a). Copyright © 2017 Elsevier B.V. All rights reserved.

Rock & Roll : Waste seperation

NARCIS (Netherlands)

Beunder, L.; Rem, P.C.; Van Den Berg, R.

2000-01-01

Five hundred tonnes of glass, 1 million tonnes of plastic,14 million tonnes of building and demolition waste, 7 million tonnes of household waste, 3 million tonnes of packaging, 3.5 million tonnes of paper and board, and 300,000 old cars. All part of the annual harvest of waste materials in the

Waste/Rock Interactions Technology Program: the status of radionuclide sorption-desorption studies performed by the WRIT program

International Nuclear Information System (INIS)

Serne, R.J.; Relyea, J.F.

1982-04-01

The most credible means for radionuclides disposed as solid wastes in deep-geologic repositories to reach the biosphere is through dissolution of the solid waste and subsequent radionuclide transport by circulating ground water. Thus safety assessment activities must consider the physicochemical interactions between radionculides present in ground water with package components, rocks and sediments since these processes can significantly delay or constrain the mass transport of radionuclides in comparison to ground-water movement. This paper focuses on interactions between dissolved radiouclides in ground water and rocks and sediments away from the near-field repository. The primary mechanism discussed is adsorption-desorption, which has been studied using two approaches. Empirical studies of adsorption-desorption rely on distribution coefficient measurements while mechanism studies strive to identify, differentiate and quantify the processes that control nuclide retardation

Controls on Weathering of Pyrrhotite in a Low-Sulfide, Granitic Mine-Waste Rock in the Canadian Arctic

Science.gov (United States)

Langman, J. B.; Holland, S.; Sinclair, S.; Blowes, D.

2013-12-01

Increased environmental risk is incurred with expansion of mineral extraction in the Arctic. A greater understanding of geochemical processes associated with hard-rock mining in this cold climate is needed to evaluate and mitigate these risks. A laboratory and in-situ experiment was conducted to examine mineral weathering and the generation of acid rock drainage in a low-sulfide, run-of-mine waste rock in an Arctic climate. Rock with different concentrations of sulfides (primarily pyrrhotite [Fe7S8] containing small amounts of Co and Ni) and carbonates were weathered in the laboratory and in-situ, large-scale test piles to examine leachate composition and mineral weathering. The relatively larger sulfide-containing rock produced sufficient acid to overcome carbonate buffering and produced a declining pH environment with concomitant release of SO4, Fe, Co, and Ni. Following carbonate consumption, aluminosilicate buffering stabilized the pH above 4 until a reduction in acid generation. Results from the laboratory experiment assisted in determining that after consumption of 1.6 percent of the total sulfide, the larger sulfide-concentration test pile likely is at an internal steady-state or maximal weathering rate after seven years of precipitation input and weathering that is controlled by an annual freeze-thaw cycle. Further weathering of the test pile should be driven by external factors of temperature and precipitation in this Arctic, semi-arid region instead of internal factors of wetting and non-equilibrium buffering. It is predicted that maximal weathering will continue until at least 20 percent of the total sulfide is consumed. Using the identified evolution of sulfide consumption in this Arctic climate, a variable rate factor can now be assessed for the possible early evolution and maximal weathering of larger scale waste-rock piles and seasonal differences because of changes in the volume of a waste-rock pile undergoing active weathering due to the freeze

Questa baseline and pre-mining ground-water quality investigation. 19. Leaching characteristics of composited materials from mine waste-rock piles and naturally altered areas near Questa, New Mexico

Science.gov (United States)

Smith, Kathleen S.; Hageman, Philip L.; Briggs, Paul H.; Sutley, Stephen J.; McCleskey, R. Blaine; Livo, K. Eric; Verplanck, Philip L.; Adams, Monique G.; Gemery-Hill, Pamela A.

2007-01-01

The goal of this study is to compare and contrast the leachability of metals and the acidity from individual mine waste-rock piles and natural erosional scars in the study area near Questa, New Mexico. Surficial multi-increment (composite) samples less than 2 millimeters in diameter from five waste-rock piles, nine erosional-scar areas, a less-altered site, and a tailings slurry-pipe sample were analyzed for bulk chemistry and mineralogy and subjected to two back-to-back leaching procedures. The first leaching procedure, the U.S. Geological Survey Field Leach Test (FLT), is a short-duration leach (5-minute shaking and 10-minute settling) and is intended to leach readily soluble materials. The FLT was immediately followed by an 18-hour, end-over-end rotation leaching procedure. Comparison of results from the back-to-back leaching procedures can provide information about reactions that may take place upon migration of leachates through changing geochemical conditions (for example, pH changes), both within the waste-rock and scar materials and away from the source materials. For the scar leachates, the concentrations of leachable metals varied substantially between the scar areas sampled. The scar leachates have low pH (pH 3.2-4.1). Under these low-pH conditions, cationic metals are solubilized and mobile, but anionic species, such as molybdenum, are less soluble and less mobile. Generally, metal concentrations in the waste-rock leachates did not exceed the upper range of those metal concentrations in the erosional-scar leachates. One exception is molybdenum, which is notably higher in the waste-rock leachates compared with the scar leachates. Most of the waste-rock leachates were at least mildly acidic (pH 3.0-6.2). The pH values in the waste-rock leachates span a large pH range that includes some pH-dependent solubility and metal-attenuation reactions. An increase in pH with leaching time and agitation indicates that there is pH-buffering capacity in some of the

Creep in the sparsely fractured rock between a disposal vault and a zone of highly fractured rock

International Nuclear Information System (INIS)

Wilkins, B.J.S.; Rigby, G.L.

1993-08-01

AECL Research is responsible for investigating the feasibility and safety of the disposal of Canada's nuclear fuel waste deep in the plutonic rock of the Canadian Shield. The excavation of the disposal vault, the installation of sealing systems and the heat generated by the fuel waste will all perturb the in situ stress state of the rock mass. This computer codes HOTROK, MCROC and MCDIRC are used to analyze the influence of these stress perturbations on the mechanical behaviour of the rock mass. Time-dependent microcracking of the rock mass will lead to creep around openings in the vault. The analysis specifically estimates the resulting creep strain in the sparsely fractured rock between the edge of the disposal vault and a postulated zone of highly fractured rock. The estimates are extremely conservative. The conclusion reached is that the rock mass more than 3 m beyond the edge of the vault will experience < 0.001 creep strain 100 000 years after the fuel waste is emplaced. (author). 10 refs., 4 tabs., 4 figs

Growth rate characteristics of acidophilic heterotrophic organisms from mine waste rock piles

Science.gov (United States)

Yacob, T. W.; Silverstein, J.; Jenkins, J.; Andre, B. J.; Rajaram, H.

2010-12-01

Autotrophic iron oxidizing bacteria play a key role in pyrite oxidation and generation of acid mine drainage AMD. Scarcity of organic substrates in many disturbed sites insures that IOB have sufficient oxygen and other nutrients for growth. It is proposed that addition of organic carbon substrate to waste rock piles will result in enrichment of heterotrophic microorganisms limiting the role of IOB in AMD generation. Previous researchers have used the acidophilic heterotroph Acidiphilium cryptum as a model to study the effects of organic substrate addition on the pyrite oxidation/AMD cycle. In order to develop a quantitative model of effects such as competition for oxygen, it is necessary to use growth and substrate consumption rate expressions, and one approach is to choose a model strain such as A. cryptum for kinetic studies. However we have found that the growth rate characteristics of A. cryptum may not provide an accurate model of the remediation effects of organic addition to subsurface mined sites. Fluorescent in-situ hybridization (FISH) assays of extracts of mine waste rock enriched with glucose and yeast extract did not produce countable numbers of cells in the Acidiphilium genus, with a detection limit of3 x 104 cells/gram rock, despite evidence of the presence of well established heterotrophic organisms. However, an MPN enrichment produced heterotrophic population estimates of 1x107 and 1x109 cells/gram rock. Growth rate studies of A. cryptum showed that cultures took 120 hours to degrade 50% of an initial glucose concentration of 2,000 mg/L. However a mixed culture enriched from mine waste rock consumed 100% of the same amount of glucose in 24 hours. Substrate consumption data for the mixed culture were fit to a Monod growth model: {dS}/{dt} = μ_{max}S {( {X_0}/{Y} + S_0 -S )}/{(K_s +S)} Kinetic parameters were estimated utilizing a non linear regression method coupled with an ODE solver. The maximum specific growth rate of the mixed population with �

A theoretical and numerical consideration of rock mass behaviour under thermal loading of radioactive waste repository

International Nuclear Information System (INIS)

Reivinen, M.; Freund, J.; Eloranta, E.

1996-08-01

The aim of the study is to model the geodynamic response of a ground rock block under horizontal stresses and also consider the thermal fields and deformations, especially on the ground surface, caused by the heat produced by nuclear waste. (12 refs.)

Recent studies on radiation damage formation in synthetic NaCl and natural rock salt for radioactive waste disposal applications

International Nuclear Information System (INIS)

Swyler, K.J.; Klaffky, R.W.; Levy, P.W.

1980-01-01

Radiation damage formation in natural rock salt is described as a function of irradiation temperature and plastic deformation. F-center formation decreases with increasing temperature while significant colloidal sodium formation occurs over a restricted temperature range around 150 0 C. Plastic deformation increases colloid formation; it is estimated that colloid concentrations may be increased by a factor of 3 if the rock salt near radioactive waste disposal canisters is heavily deformed. Optical bandshape analysis indicates systematic differences between the colloids formed in synthetic and natural rock salts

Geophysical study in waste landfill localized above fractured rocks

Directory of Open Access Journals (Sweden)

Ariveltom Cosme da Silva

2011-08-01

Full Text Available Geophysical survey is an important method for investigation of contaminated areas used in the characterization of contrasting physical properties in the presence of pollutants. This work applied the geophysical methods of Electrical Resistivity and Self Potential in waste landfill, located in Caçapava do Sul city, RS. The landfill is located over fractured metamorphic rocks. Eight lines of electrical profiling with 288 measures of self potential were done. In addition, 83 measurements of direction and dip of fractures were taken. The application of spontaneous potential method permitted to detect the direction of groundwater flow. The electrical resistivity measurements allowed the identification of low-intensity anomalies associated with the presence of leachate. There is a relationship between anomalous zones and the directions of fractures.

Importance of creep failure of hard rock in the near field of a nuclear-waste repository

International Nuclear Information System (INIS)

Blacic, J.D.

1981-01-01

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository

Importance of creep failure of hard rock in the near field of a nuclear waste repository

Energy Technology Data Exchange (ETDEWEB)

Blacic, J D [Los Alamos National Laboratory, NM, (USA)

1982-12-31

Potential damage resulting from slow creep deformation intuitively seems unlikely for a high-level nuclear waste repository excavated in hard rock. However, recent experimental and modeling results indicate that the processes of time-dependent microcracking and water-induced stress corrosion can lead to significant reductions in strength and alteration of other key rock properties in the near-field region of a repository. We review the small data base supporting these conclusions and stress the need for an extensive laboratory program to obtain the new data that will be required for design of a repository.

Possibility of Radioactive and Toxic WasteDisposal in a Rock Ssalt Deposits in Slovakia Combining Wells and Cavities

Directory of Open Access Journals (Sweden)

Škvareková Erika

2004-09-01

Full Text Available Disposal of radioactive and toxic waste in rock salt can be performed in two ways – disposal in the salt mine repository or disposal in the deep wells connected with salt cavity. Presented article deals with the option of the disposal in a salt cavity at medium depths. The article also cover partially salt deposits in Slovakia and their potential suitability for waste disposal..

The TIMODAZ project: Thermal impact on the damaged zone around a radioactive waste disposal in clay host rocks

International Nuclear Information System (INIS)

XiangLing, L.

2009-01-01

The management of spent nuclear fuel and other long-lived radio active waste is an important environmental issue today. Disposal in deep clay geological formations is one of the promising options to dispose of these wastes. In this context, the related research activities in the Euratom Framework Programme of European Commission are continually taking on an enhanced significance. The TIMODAZ is one of the STREP projects (Specific Targeted Research Project) in the Sixth EURATOM Framework Programme and contributes to the research related to the geological disposal of radioactive waste. The consortium is composed of a strong multidisciplinary team involving both European radioactive waste management organizations and nuclear research institutes, universities, industrial partners as well as consultancy companies (SME's). Totally, 15 partners coming from 8 countries are involved with a total budget of about 4000k EURO. Being the coordinator (through the EURIDICE expertise group), SCK-CEN plays the leading role in the project. Meanwhile, SCK-CEN participates the research in different work packages covering the laboratory tests, in-situ tests as well as the integration of TIMODAZ results within the safety case. An important item for the long-term safety of underground disposal is the proper evaluation of the DZ (damaged zone) in the clay host rock. The DZ is defined here as the zone of host rock that experiences THMC (Thermo-Hydro-Mechanical-Chemical) modifications induced by the repository, with potential major changes in the transport properties for radionuclides. The DZ is first initiated during the repository construction. Its behaviour is dynamic, dependent on changing conditions that vary from the open-drift period, to initial closure period and to the entire heating-cooling cycle of the decaying waste. The early THMC disturbances created by the excavation, the operational phase and the thermal load might be the most severe transient that the repository will undergo

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

Energy Technology Data Exchange (ETDEWEB)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-06-20

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Investigations of Near-Field Thermal-Hydrologic-Mechanical-Chemical Models for Radioactive Waste Disposal in Clay/Shale Rock

International Nuclear Information System (INIS)

Liu, H.H.; Li, L.; Zheng, L.; Houseworth, J.E.; Rutqvist, J.

2011-01-01

Clay/shale has been considered as potential host rock for geological disposal of high-level radioactive waste throughout the world, because of its low permeability, low diffusion coefficient, high retention capacity for radionuclides, and capability to self-seal fractures. For example, Callovo-Oxfordian argillites at the Bure site, France (Fouche et al., 2004), Toarcian argillites at the Tournemire site, France (Patriarche et al., 2004), Opalinus Clay at the Mont Terri site, Switzerland (Meier et al., 2000), and Boom clay at the Mol site, Belgium (Barnichon and Volckaert, 2003) have all been under intensive scientific investigation (at both field and laboratory scales) for understanding a variety of rock properties and their relationships to flow and transport processes associated with geological disposal of radioactive waste. Figure 1-1 presents the distribution of clay/shale formations within the USA.

Geological assessment of crystalline rock formations with a view to radioactive waste disposal

International Nuclear Information System (INIS)

Mather, J.D.

1984-01-01

Field work has been concentrated at the Altnabreac Research Site on north-east Scotland, where three deep boreholes to approximately 300 m and 24 shallow boreholes to approximately 40 m were drilled. The movement of groundwater within 300 m of the surface was investigated using a specially developed straddle packer system. Geochemical studies have demonstrated that most groundwater is dominated by recent recharge but one borehole yielded water with an age of around 10 4 years. Geophysical borehole logging has shown that the full wave train sonic logs and the acoustic logs show most promise for the assessment of crystalline rocks. In the laboratory the interaction of rocks and groundwater at the temperature/pressure conditions to be expected in a repository has established the geochemical environment to which waste canisters and backfill materials would be subjected. Other generic studies reported include the characterization of geotechnical properties of rocks at elevated temperatures and pressures, the development of a new cross-hole sinusoidal pressure test for the measurement of hydraulic properties and the use of thermal infra-red imagery to detect groundwater discharge zones

Host Rock Classification (HRC) system for nuclear waste disposal in crystalline bedrock

International Nuclear Information System (INIS)

Hagros, A.

2006-01-01

A new rock mass classification scheme, the Host Rock Classification system (HRC-system) has been developed for evaluating the suitability of volumes of rock mass for the disposal of high-level nuclear waste in Precambrian crystalline bedrock. To support the development of the system, the requirements of host rock to be used for disposal have been studied in detail and the significance of the various rock mass properties have been examined. The HRC-system considers both the long-term safety of the repository and the constructability in the rock mass. The system is specific to the KBS-3V disposal concept and can be used only at sites that have been evaluated to be suitable at the site scale. By using the HRC-system, it is possible to identify potentially suitable volumes within the site at several different scales (repository, tunnel and canister scales). The selection of the classification parameters to be included in the HRC-system is based on an extensive study on the rock mass properties and their various influences on the long-term safety, the constructability and the layout and location of the repository. The parameters proposed for the classification at the repository scale include fracture zones, strength/stress ratio, hydraulic conductivity and the Groundwater Chemistry Index. The parameters proposed for the classification at the tunnel scale include hydraulic conductivity, Q' and fracture zones and the parameters proposed for the classification at the canister scale include hydraulic conductivity, Q', fracture zones, fracture width (aperture + filling) and fracture trace length. The parameter values will be used to determine the suitability classes for the volumes of rock to be classified. The HRC-system includes four suitability classes at the repository and tunnel scales and three suitability classes at the canister scale and the classification process is linked to several important decisions regarding the location and acceptability of many components of

Concepts and Technologies for Radioactive Waste Disposal in Rock Salt

Directory of Open Access Journals (Sweden)

Wernt Brewitz

2007-01-01

Full Text Available In Germany, rock salt was selected to host a repository for radioactive waste because of its excellent mechanical properties. During 12 years of practical disposal operation in the Asse mine and 25 years of disposal in the disused former salt mine Morsleben, it was demonstrated that low-level wastes (LLW and intermediate-level wastes (ILW can be safely handled and economically disposed of in salt repositories without a great technical effort. LLW drums were stacked in old mining chambers by loading vehicles or emplaced by means of the dumping technique. Generally, the remaining voids were backfilled by crushed salt or brown coal filter ash. ILW were lowered into inaccessible chambers through a borehole from a loading station above using a remote control.Additionally, an in-situ solidification of liquid LLW was applied in the Morsleben mine. Concepts and techniques for the disposal of heat generating high-level waste (HLW are advanced as well. The feasibility of both borehole and drift disposal concepts have been proved by about 30 years of testing in the Asse mine. Since 1980s, several full-scale in-situ tests were conducted for simulating the borehole emplacement of vitrified HLW canisters and the drift emplacement of spent fuel in Pollux casks. Since 1979, the Gorleben salt dome has been investigated to prove its suitability to host the national final repository for all types of radioactive waste. The “Concept Repository Gorleben” disposal concepts and techniques for LLW and ILW are widely based on the successful test operations performed at Asse. Full-scale experiments including the development and testing of adequate transport and emplacement systems for HLW, however, are still pending. General discussions on the retrievability and the reversibility are going on.

Basic investigation and analysis for preferred host rocks and natural analogue study area with reference to high level radioactive waste disposal

Energy Technology Data Exchange (ETDEWEB)

Seo, Jeong Ryul; Park, J. K.; Hwang, D. H.; Lee, J. H.; Yun, H. S.; Kim, D. Y.; Park, H. S.; Koo, S. B.; Cho, J. D.; Kim, K. E. [Korea Inst. of Geology, Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

The purpose of this study is basic investigation and analysis for preferred host rocks and natural analogue study area to develope underground disposal technique of high level radioactive waste in future. The study has been done for the crystalline rocks(especially granitic rocks) with emphasis of abandoned metallic mines and uranium ore deposits, and for the geological structure study by using gravity and aeromagnetic data. 138 refs., 54 tabs., 130 figs. (author)

Modeling of a sedimentary rock alternative for the siting of the radioactive waste disposal system

International Nuclear Information System (INIS)

Fuentes, Nestor O.

2007-01-01

Here are described the main concepts, the approximations, and all those simulation aspects that characterize the modeling performed using the unsaturated saturated approach for porous media. The objective of this work is to obtain a generic description of a sedimentary rock soil as an alternative site for the low and intermediate level radioactive waste disposal system. (author) [es

Site investigation methods used in Canada's nuclear fuel waste management program to determine the hydrogeological conditions of plutonic rock

International Nuclear Information System (INIS)

Davison, C.C.

1985-01-01

Atomic Energy of Canada Limited (AECL) is investigating the concept of disposing of Canada's nuclear fuel wastes in a mined vault at a depth of 500 m to 1000 m within a plutonic rock body. Much effort has been directed at developing site investigation methods that can be used to determine the hydrogeological conditions of plutonic rock bodies. The primary objective of this research is to define the physical and chemical characteristics of groundwater flow systems at the various scales that are relevant to the prediction of potential radionuclide migration from a disposal vault. Groundwater movement through plutonic rock is largely controlled by fractures within the rock, and the hydrogeological parameters of fractured geological media are extremely scale dependent

Nuclear waste disposal

International Nuclear Information System (INIS)

Lindblom, U.; Gnirk, P.

1982-01-01

The subject is discussed under the following headings: the form and final disposal of nuclear wastes; the natural rock and groundwater; the disturbed rock and the groundwater; long-term behavior of the rock and the groundwater; nuclear waste leakage into the groundwater; what does it all mean. (U.K.)

Radionuclide Transport in Fractured Rock: Numerical Assessment for High Level Waste Repository

Directory of Open Access Journals (Sweden)

Claudia Siqueira da Silveira

2013-01-01

Full Text Available Deep and stable geological formations with low permeability have been considered for high level waste definitive repository. A common problem is the modeling of radionuclide migration in a fractured medium. Initially, we considered a system consisting of a rock matrix with a single planar fracture in water saturated porous rock. Transport in the fracture is assumed to obey an advection-diffusion equation, while molecular diffusion is considered the dominant mechanism of transport in porous matrix. The partial differential equations describing the movement of radionuclides were discretized by finite difference methods, namely, fully explicit, fully implicit, and Crank-Nicolson schemes. The convective term was discretized by the following numerical schemes: backward differences, centered differences, and forward differences. The model was validated using an analytical solution found in the literature. Finally, we carried out a simulation with relevant spent fuel nuclide data with a system consisting of a horizontal fracture and a vertical fracture for assessing the performance of a hypothetical repository inserted into the host rock. We have analysed the bentonite expanded performance at the beginning of fracture, the quantified radionuclide released from a borehole, and an estimated effective dose to an adult, obtained from ingestion of well water during one year.

THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics

International Nuclear Information System (INIS)

Czaikowski, Oliver

2012-01-01

Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

Use of overburden rocks from open-pit coal mines and waste coals of Western Siberia for ceramic brick production with a defect-free structure

Science.gov (United States)

Stolboushkin, A. Yu; Ivanov, A. I.; Storozhenko, G. I.; Syromyasov, V. A.; Akst, D. V.

2017-09-01

The rational technology for the production of ceramic bricks with a defect-free structure from coal mining and processing wastes was developed. The results of comparison of physical and mechanical properties and the structure of ceramic bricks manufactured from overburden rocks and waste coal with traditional for semi-dry pressing mass preparation and according to the developed method are given. It was established that a homogeneous, defect-free brick texture obtained from overburden rocks of open-pit mines and waste coal improves the quality of ceramic wall materials produced by the method of compression molding by more than 1.5 times compared to the brick with a traditional mass preparation.

Five-year performance monitoring of a high-density polyethylene (HDPE) cover system at a reclaimed mine waste rock pile in the Sydney Coalfield (Nova Scotia, Canada).

Science.gov (United States)

Power, Christopher; Ramasamy, Murugan; MacAskill, Devin; Shea, Joseph; MacPhee, Joseph; Mayich, David; Baechler, Fred; Mkandawire, Martin

2017-12-01

Cover systems are commonly placed over waste rock piles (WRPs) to limit atmospheric water and oxygen ingress and control the generation and release of acid mine drainage (AMD) to the receiving environment. Although covers containing geomembranes such as high-density polyethylene (HDPE) exhibit the attributes to be highly effective, there are few, if any, published studies monitoring their performance at full-scale WRPs. In 2011, a HDPE cover was installed over the Scotchtown Summit WRP in Nova Scotia, Canada, and extensive field performance monitoring was conducted over the next five years. A range of parameters within the atmosphere, cover, waste rock, groundwater and surface water, were monitored and integrated into a comprehensive hydrogeochemical conceptual model to assess (i) atmospheric ingress to the waste rock, (ii) waste rock acidity and depletion and (iii) evolution of groundwater and surface water quality. Results demonstrate that the cover is effective and meeting site closure objectives. Depletion in oxygen influx resulted in slower sulphide oxidation and AMD generation, while a significant reduction in water influx (i.e. 512 to 50 mm/year) resulted in diminished AMD release. Consistent improvements in groundwater quality (decrease in sulphate and metals; increase in pH) beneath and downgradient of the WRP were observed. Protection and/or significant improvement in surface water quality was evident in all surrounding watercourses due to the improved groundwater plume and elimination of contaminated runoff over previously exposed waste rock. A variably saturated flow and contaminant transport model is currently being developed to predict long-term cover system performance.

Parameter-sensitivity analysis of near-field radionuclide transport in buffer material and rock for an underground nuclear fuel waste vault

International Nuclear Information System (INIS)

Cheung, S.C.H.; Chan, T.

1983-08-01

An analytical model has been developed for radionuclide transport in the vicinity of a nuclear fuel waste container emplaced in a borehole. The model considers diffusion in the buffer surrounding the waste container, and both diffusion and groundwater convection in the rock around the borehole. A parameter-sensitivity analysis has been done to study the effects on radionuclide flux of (a) Darcian velocity of groundwater in the rock, (b) effective porosity of the buffer, (c) porosity of the rock, (d) radial buffer thickness, and (e) radius and length of the container. It is found that the radionuclide flux, Fsub(R), and the total integrated flux, Fsub(T), are greater for horizontal flow than for vertical flow; Fsub(R) decreases with increasing radial buffer thickness for all Darcian velocities, whereas Fsub(T) decreases at high velocities but increases at low velocities. The rate of change of Fsub(R) and of Fsub(T) decreases with decreasing flow velocity and increasing buffer thickness; Fsub(R) is greater for higher effective porosity of buffer or rock; and Fsub(R) increases and Fsub(T) decreases with decreasing container radius or length

Review of potential host rocks for radioactive waste disposal in the southeast United States: Southeastern Coastal Plain Subregion

International Nuclear Information System (INIS)

1980-10-01

A literature review was made of the geological characteristics of the Southeastern Coastal Plain physiograhic province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose of this study was to identify candidate exploration areas for the possible location of a mined repository for the storage of radioactive waste in the argillaceous sedimentary rocks of the Coastal Plain. Candidate areas were selected on the basis of geological characteristics, available subsurface data, and generally accepted requirements for waste isolation developed by previous studies. Factors considered in the evaluation include the stratigraphy and lithology, geologic history, structure, seismicity, hydrogeology, and natural resources of the candidate area. Unlike other potential regions, the Southeastern Coastal Plain is not composed of competent rock, but consists primarily of unconsolidated and water-saturated sediments overlying a basement of crystalline and metavolcanic rocks. Thus, construction of both shafts and tunnels to depths of approx. 1000 meters may encounter difficulties. Socio-economic and construction considerations have not been addressed in the evaluation. Based on the applied criteria, four areas were selected as being most favorable for future field investigation. These include one in Maryland, one in North Carolina, and two in Georgia

Interim guidelines on performance constraints for nuclear waste disposal in crystalline rock

International Nuclear Information System (INIS)

1984-01-01

Performance constraint guidelines have been developed for geologic disposal of nuclear waste in crystalline rock. The approach taken in defining these guidelines was to consider the thermal, thermomechanical, and thermochemical behavior for three regions (very-near field, near field, and far field) of the repository during three time periods (operational, containment, and isolation) associated with the disposal system. Limits are proposed to ensure compliance with the current repository criteria proposed by the United States Nuclear Regulatory Commission (NRC) concerning repository siting and performance assessment. These criteria are: Substantial containment of all radionuclides within the waste package for a period of time between 300 and 1000 years after emplacement. Release rate after loss of containment of one part in 100,000 annually per radionuclide based on the nuclides inventory when the waste package is breached, and in situ ground-water transit time of 1000 years from the repository horizon to the accessible environment, compliance with the performance constraint guidelines presented herein will be required to ensure that the final repository design is in compliance with NRC criteria. The constraint guidelines have also been developed to satisfy the requirement for technical conservatism. 40 refs., 14 figs., 4 tabs

Modelling of thermo-hydro-mechanical couplings and damage of viscoplastic rocks in the context of radioactive waste storage

International Nuclear Information System (INIS)

Kharkhour, H.

2002-12-01

Trying to develop a model taking into account the complex rheology of a geologic media characterized by visco-plasticity, damage and thermo-hydro-mechanical couplings is unusual in geotechnics. This is not the case for radioactive waste storage that presents specificities from several viewpoints. Indeed, the scales of time and space concerned by this type of storage are disproportionate to those of civil engineering works or mines. Another specificity of the radioactive waste storage lies in the coupled processes involved. No effect likely to compromise the long-term security of the storage could be ignored. For example this is the case of damage, a phenomenon which does not necessarily lead to a major change of the mechanical behavior of the works but can influence the permeability of the medium in relation with a migration of radionuclides. It can be conceived that this phenomenon finds all its importance in the context of the thermo-hydro-mechanical couplings of a waste storage with high activity. However, the interaction between the damage and the THM coupled processes was the object of very few research subject up to now. This. is even more true for viscoplastic media considered as ductile, and therefore, less prone to cracking than brittle media. It is exactly in this 'original' but difficult context that took place the research presented in this report. This study was dedicated to the analysis of the phenomena and the thermal, hydraulic and mechanical couplings occurring in the near and far field of a high activity radioactive waste storage. Two examples of geological media were considered in this report: the clayey rock of Callovo-Oxfordian, called ' Argilites de l'Est ', target rock of the ANDRA project to carry out a subterranean laboratory for the study of long life radioactive waste storage; and the salt rock of the. subterranean laboratory in the old salt mine of Asse in Germany. (author)

Rationale for geological isolation of high-level radioactive waste, and assessment of the suitability of crystalline rocks

International Nuclear Information System (INIS)

Smedes, H.W.

1980-01-01

This report summarizes the disposal objective to be met and the requisite geotechnical criteria to meet that objective; evaluates our present ability to determine whether certain criteria can be met and to predict whether they will continue to be met; discusses the consequences of failure to meet certain criteria; assesses what is known about how crystalline rocks meet those criteria; lists important gaps in our knowledge that presently preclude final assessment of suitability; and suggests priority research to fill those gaps. The report presents an elaboration of the above-stated behavior and suitability of crystalline rocks, and a rationale of site-selection in support of the recommended prompt and intensive study of granite and other crystalline rocks as potentially highly suitable candidate media for radioactive waste disposal. An overview is presented on what the rocks are, where they are, and what the critical attributes are of various crystalline-rock terranes in the conterminous United States. This is intended to provide a basis to aid in selecting, first regions, and then sites within those regions, as candidate repository sites

Review of potential host rocks for radioactive waste disposal in the Piedmont Province of Virginia and Maryland

International Nuclear Information System (INIS)

Brown, W.R.

1980-10-01

This study is a detailed follow-up of a broad study of the Southeastern Piedmont by Acres American, Inc. (1978) based upon literature and existing knowledge. The purpose is to designate broad areas in which the rock type is favorable for field exploration for the possible designation of a site for disposal of solidified radioactive waste. The Acres study classified rock units as favorable, potentially favorable, and unfavorable. The objective of the present study is: (1) to review the criteria used in this classification, and (2) on the basis of a detailed knowledge of local rock units to reassign the rock types in the potentially favorable category to either the favorable or the unfavorable categories. As in the Acres study, the objective is to designate field study areas, not potential sites. This study was based entirely upon a literature study, discussions with persons knowledgeable of the region, and a personal acquaintance with the rocks and structures. No field work was done specifically for this project. No consideration was given to sociological, economic, or non-technical factors

Thermomigration of fluid inclusions in rock salt. Implications for the disposal of nuclear wastes

International Nuclear Information System (INIS)

Noack, W.; Runge, K.

1984-01-01

A mathematical model has been suggested to predict the time-dependent accumulation of brine at nuclear waste packages emplaced in a rock salt repository owing to thermomigration of brine inclusions. The model is based mainly on a description of the migration rate as a function of the temperature, temperature gradient, inclusion size and gas/liquid ratio of inclusions. Other factors are treated merely as disturbing quantities with respect to the migration rate. (author)

Radioactive waste storage in mined caverns in crystalline rock: results of field investigations at Stripa, Sweden

International Nuclear Information System (INIS)

Witherspoon, P.A.

1980-10-01

It is generally agreed that the most practicable method of isolating nuclear wastes from the biosphere is by deep burial in suitable geologic formations. Such burial achieves a high degree of physical isolation but raises questions concerning the rate at which some of these wastes may return to the biosphere through transport by groundwater. Any suitable repository site will be disturbed first by excavation and second by the thermal pulse caused by the radioactive decay of the wastes. To assess the effectiveness of geologic isolation it is necessary to develop the capability of predicting the response of a rock mass to such a thermal pulse. Ultimately, this requires field measurements below the surface in media representative of those likely to be encountered at an actual repository. Access to a granitic rock mass adjacent to a defunct iron ore mine at Stripa, Sweden, at a depth of about 350 m below surface has provided a unique opportunity to conduct a comprehensive suite of hydrological and thermo-mechanical experiments under such conditions. The results of these field tests have shown the importance of geologic structure and the functional dependence of the thermo-mechanical properties on temperature in developing a valid predictive model. The results have also demonstrated the vital importance of carrying out large-scale investigations in a field test facility

Role of HHM coupling mechanisms on the evolution of rock masses around nuclear waste disposals in the context of gas generation

International Nuclear Information System (INIS)

Hoxha, D.; Do, D.-P.; Wendling, J.; Poutrel, A.

2010-01-01

Document available in extended abstract form only. This paper aims at modelling of long term evolution of hydro-mechanical state of rock masses around sealing nuclear waste disposals. In the principles of nuclear waste disposals the geological barrier must play a long term confining role in respect with nuclide transport. In terms of hydro-mechanical properties this calls for managing the damage around the underground workings of the waste disposals. In particular the seal buffers and barrier rock will support the generation of hydrogen of different origins, mainly from the corrosion of steals used in various elements of a nuclear waste disposal. This generation would generate gas pressures sufficiently high to partially dry seal or barrier rock leading to a redistribution of stress around underground openings, to a reactivation of the rock damage and finally could put in question the concept of geological barrier itself. The object of this paper is to shed light in the mechanisms of HHM coupling in rocks around a repository by comparative numerical analyses. Basically, we chose two configurations to proceed with analyses: one in plan strain conditions and the other an axial symmetric configuration. The goal of the first configuration is the assessment of gas pressure evolution in the openings of a repository. The principal input of the problem is the kinetics of gas generation (H 2 generation) given by a step-wise function of time describing the gas generation of one single nuclear waste coli. Then known the repository architecture one could easily calculate the mass of gas generated on one access gallery. Since extreme scenario is studied, we suppose that the gas generated by the set of alveoli is fully located in the access gallery and only a radial gas flux is possible.The hydro mechanical properties of rocks up to the surface were taken into account. For the callovo-Oxfordian clay that constitutes barrier rock in immediate neighbouring of the gallery a model

Exploration of cystalline rocks for nuclear waste repositories: Some strategies for area characterization

International Nuclear Information System (INIS)

Trask, N.J.; Roseboom, E.H.; Watts, R.D.; Bedinger, M.S.

1991-01-01

A general strategy for the exploration of crystalline rock massed in the eastern United States for the identification of potential sites for high-level radioactive waste repositories has been generated by consideration of the Department of Energy (DOE) Siting Guidelines, available information on these crystalline rocks, and the capabilities and limitations of various exploration methods. The DOE has recently screened over 200 crystalline rock massed in 17 states by means of literature surveys and has recommended 12 rock masses for more intensive investigation including field investigations. The suggested strategy applies to the next stage of screen where the objective is to identify those potential sites that merit detailed site characterization including an exploratory shaft and underground study. This document discusses strategies for reconnaissance and field investigations, including the early phases of drilling, to provide geoscience information on the areas under construction. A complete Area Characterization Plan, to be developed by DOE with involvement of the states within which the areas to be studied are located, will outline all of the investigations to be carried out in the area phase including their cost and scheduling. Here, we provide input for the Area Characterization Plan by discussing what we believe to be the most important issues that need to be addressed in this phase and suggesting methods for their resolution. This report is not intended as a complete outline of area phase geoscience investigations, however. 79 refs., 4 figs

Acoustic remote monitoring of rock and concrete structures for nuclear waste repositories

International Nuclear Information System (INIS)

Young, R.P.

2000-01-01

Excavation and thermally induced damage is of significance for many types of engineering structures but no more so than in the case of nuclear waste repository design. My research and that of my group, formally at Queen's University Canada and Keele University UK and now at the University of Liverpool UK, has focused on the development of acoustic techniques for the in situ detection and quantification of induced damage and fracturing. The application of earthquake seismology to this problem has provided the opportunity to study the micro mechanics of damage mechanisms in situ and provide validation data for predictive geomechanical models used for engineering design. Since 1987 I have been a principal investigator at Atomic Energy of Canada's Underground Research Laboratory (URL), responsible for the development of acoustic emission techniques (AE). In the last twelve years, the application of acoustic techniques to rock damage assessment has been pioneered by my group at the URL and successfully applied in several other major international projects including the ZEDEX, Retrieval and Prototype repository experiments at the Aspo Hard Rock Laboratory (HRL) of SKB Sweden. In this paper I describe what information is available by remote acoustic monitoring of rock and concrete structures and demonstrate this with reference to two international scientific experiments carried out at the URL Canada and the HRL Sweden. (author)

Nuclear fuel waste management program geotechnical studies of Eye-Dashwa Lakes research area rock properties

International Nuclear Information System (INIS)

Chernis, P.J.; Robertson, P.B.

1992-05-01

The Eye-Dashwa Lakes pluton near Atikokan Ontario has been used as a study area for the Canadian nuclear fuel waste management research program. The pluton consists predominately of granite. Fractures formed during cooling of the pluton were filled with a succession of different materials at different times. Measurements of a series of geophysical and geotechnical properties of rock samples are published here in this report, including especially microcrack and pore structures. An indication has been found that a larger proportion of the porosity of Whiteshell and Atikokan samples is contained in connecting pores, compared to other rocks. This may seem surprising in view of the finding that approximately 70% of the effective porosity of Atikokan samples is contained in pockets

Summary of INEL research on the iron-enriched basalt waste form

International Nuclear Information System (INIS)

Reimann, G.A.; Grandy, J.D.; Eddy, T.L.; Anderson, G.L.

1992-01-01

This report summarizes the knowledge base on the iron-enriched basalt (IEB) waste form developed at the Idaho National Engineering Laboratory (INEL) during 1979--1982. The results presented discuss the applicability of IEB in converting retrieved transuranic (TRU) waste from INEL's Radioactive Waste Management Complex (RWMC) into a vitreous/ceramic (glassy/rock) stable waste form suitable for permanent disposal in an appropriate repository, such as the Waste Isolation Pilot Plant (WIPP) in New Mexico. Borosilicate glass (BSG), the approved high-level waste form, appears unsuited for this application. Melting the average waste-soil mix from the RWMC produces the IEB composition and attempting to convert IEB to the BSG composition would require additions of substantial B 2 0 3 , Na, and SiO 2 (glass frit). IEB requires processing temperatures of 1400 to 1600 degrees C, depending upon the waste composition. Production of the IEB waste form, using Joule heated melters, has proved difficult in the past because of electrode and refractory corrosion problems associated with the high temperature melts. Higher temperature electric melters (arc and plasma) are available to produce this final waste form. Past research focused on extensive slag property measurements, waste form leachability tests, mechanical, composition, and microstructure evaluations, as well as a host of experiments to improve production of the waste form. Past INEL studies indicated that the IEB glass-ceramic is a material that will accommodate and stabilize a wide range of heterogeneous waste materials, including long lived radionuclides and scrap metals, while maintaining a superior level of chemical and physical performance characteristics. Controlled cooling of the molten IEB and subsequent heat treatment will produce a glass-ceramic waste form with superior leach resistance

Effluents from a waste rock deposit of a former uranium mine in Saxony/Germany - Mass flow balance of water and dissolved solids

International Nuclear Information System (INIS)

Biehler, D.

2002-01-01

Soon after uranium mining had ceased in eastern Germany in 1990, work for remediation of several mining sites began. The Wismut GmbH, owner of the Mine of Dresden-Gittersee's waste rock dump, introduced the concept of reducing the impact to the environment via water and air paths by implementing a multi-layer soil cover. The deposit consists mainly of waste rock (clastic sediments of Doehlener Becken, deep metamorphic rocks) but also of low-grade ore (U-rich coal) and tailing materials. At the time when remediation started, the effluents completely infiltrated the underground. Because of previous surface exfiltration activities, they were already known to be very rich in dissolved solids, especially in sulphate and uranium. As demanded by the state authorities, the owner funded a vast hydrogeological study of the site. In testing the efficiency of surface sealing, the study indicated a mass flow balance of water and dissolved solids for the current situation, and predicted emissions into the water path which would occur after realisation of the proposed soil cover. The field investigation program consisted of: measurements of flow, of concentrations of dissolved solids (esp. U and Ra-226) and of contents of environmental isotopes in precipitation, surface runoff, seepage water and groundwater in the current condition of the dump; the study of waste rock material (geochemistry, mineralogy); waste rock material elution tests; underground investigation by drilling boreholes up to 270 m in depth. The resulting data allowed for: a hydrogeological conceptual model of the site; a consistent mass flow balance for the current condition of the dump; a prediction of concentrations in groundwater resulting after the realisation of a soil cover. The predictions show that the concentrations of dissolved solids in the contaminated groundwater would be significantly decreased. Furthermore it would be possible to reach the standards for drinking water with respect to uranium

10 CFR 960.4-2-3 - Rock characteristics.

Science.gov (United States)

2010-01-01

... DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Postclosure Guidelines § 960.4-2-3 Rock characteristics. (a) Qualifying condition. The present and... the waste could significantly decrease the isolation provided by the host rock as compared with pre...

Rock mechanics methods and in situ heater tests for design of a nuclear waste repository in basalt

International Nuclear Information System (INIS)

Board, M.P.

1978-01-01

Methods of integrating data from the Near-Surface Test Facility into the overall Waste Isolation Program are examined. Discussions are presented dealing primarily with the application of numerical models to the design of a waste repository. The various types of models currently available are discussed with reference to design in basalt and the breakdown of the problem of repository design is summarized. It is shown that the most efficient method for analyzing repository design is to break the problem down into several problems which are based on physical scale. These include the area directly surrounding a single waste canister (the very near field), the area including many canisters and canister emplacement rooms (the near field), and the area including the entire repository and the rock mass to the free surface (the far field). The methods by which numerical models are used for design are discussed. Flow charts are used to show the basic input data required, the calculational processes used, and the preliminary criteria for judgment of suitable repository performance. It is shown that the ultimate design of the allowable gross thermal loading density, and, thus, the layout of the underground workings is highly dependent upon the rock mass properties supplied as base line input data to the numerical models. Of the many input properties required, the thermal conductivity, the thermal expansion coefficient, and elastic moduli of the rock mass have, perhaps, the greatest effect on the calculation of induced temperatures, stresses, and displacements and, thus, repository design. To ensure that the design continues with confidence, field (in situ) values of input data must be obtained. The role of the Near-Surface Test Facility in situ testing in obtaining these basic required data is discussed

Heat production / host rock compatibility; Waermeentwicklung / Gesteinsvertraeglichkeit

Energy Technology Data Exchange (ETDEWEB)

Meleshyn, A.; Weyand, T.; Bracke, G.; Kull, H.; Wieczorek, K.

2016-05-15

For the final high-level radioactive waste repository potential host rock formations are either rock salt or clays (Kristallin). Heat generating waste (decay heat of the radioactive materials) can be absorbed by the host rock. The effect of temperature increase on the thermal conductivity, the thermal expansion and the mechanical properties of salt, Kristallin, clays and argilliferous geotechnical barriers are described. Further issues of the report are the mineralogical behavior, phase transformations, hydrochemistry, microbial processes, gas formation, thermochemical processes and gas ingress. Recommendations for further research are summarized.

Effect on localized waste-container failure on radionuclide transport from an underground nuclear waste vault

International Nuclear Information System (INIS)

Cheung, S.C.H.; Chan, T.

1983-07-01

In the geological disposal of nuclear fuel waste, one option is to emplace the waste container in a borehole drilled into the floor of the underground vault. In the borehole, the waste container is surrounded by a compacted soil material known as the buffer. A finite-element simulation has been performed to study the effect of localized partial failure of the waste container on the steady-state radionuclide transport by diffusion from the container through the buffer to the surrounding rock and/or backfill. In this study, the radionuclide concentration at the buffer-backfill interface is assumed to be zero. Two cases are considered at the interface between the buffer and the rock. In case 1, a no-flux boundary condition is used to simulate intact rock. In case 2, a constant radionuclide concentration condition is used to simulate fractured rock with groundwater flow. The results show that the effect of localized partial failure of the waste container on the total flux is dependent on the boundary condition at the buffer-rock interface. For the intact rock condition, the total flux is mainly dependent on the location of the failure. The total flux increases as the location changes from the bottom to the top of the emplaced waste container. For a given localized failure of the waste container, the total flux remains unaffected by the area of failed surface below the top of the failure. For fractured rock, the total flux is directly proportional to the failed surface area of the waste container regardless of the failure location

Application of Ga-Al discrimination plots in identification of high strength granitic host rocks for deep geological repository of high level radioactive waste

International Nuclear Information System (INIS)

Bajpai, R.K.; Narayan, P.K.; Trivedi, R.K.; Purohit, M.K.

2010-01-01

The permanent disposal of vitrified high level wastes and in some cases even spent fuel, is being planned in specifically designed and built deep geological repository located in the depth range of 500-600m in appropriate host rock at carefully selected sites. Such facilities are expected to provide very long term isolation and confinement to the disposed waste by means of long term mechanical stability of such structures that results from very high strength and homogeneity of the chosen rock, geochemical compatible environment around the disposed waste and general lack of groundwater. In Indian geological repository development programme, granites have been selected as target host rock and large scale characterization studies have been undertaken to develop database of mineralogy, petrology, geochemistry and rock mechanical characteristics. The paper proposes a new approach for demarcation of high strength homogeneous granite rocks from within an area of about 100 square kilometres wherein a cocktail of granites of different origins with varying rock mass characteristics co exists. The study area is characterised by the presence of A, S and I type granites toughly intermixed. The S type granites are derived from sedimentary parent material and therefore carry relics of parent fabric and at times undigested material with resultant reduction in their strength and increased inhomogeneity. On the other hand I type varieties are derived from igneous parents and are more homogeneous with sufficient strength. The A type granites are emplaced as molten mass in a complete non-tectonic setting with resultant homogeneous compositions, absence of tectonic fabric and very high strength. Besides they are silica rich with less vulnerability to alterations with time. Thus A type granites are most suited for construction of Deep Geological Repository. For developing a geochemical approach for establishing relation between chemical compositions and rock strength parameters, a

Rock salt as a medium for long-term isolation of radioactive wastes - a reassessment

International Nuclear Information System (INIS)

Chaturvedi, L.

1985-01-01

Rock salt has been regarded as a suitable medium for the permanent disposal of high and medium level radioactive wastes since the National Academy of Sciences recommended it in 1957. As a result of detained site-specific studies conducted for the Waste Isolation Pilot Plant (WIPP) project in New Mexico, however, several potential problems which are unique to bedded salt deposits have emerged. These include 1) the need to delineate the extent and rate of past dissolution and projections for the future, 2) the origin and significance of brines often found underlying the salt beds, 3) the rate and volume of migration of brine from the salt crystals towards the heat producing waste canisters, 4) the creep rates and implications for retrievability, and 5) the existence of potash and oil and gas resources with implications of human intrusion in the future. These questions will also be faced for sites in salt domes with added complications due to more complex structure and hydrology. The experience at WIPP shows that the site characterization process for high level waste repositories in bedded or dome salt should aim at identifying the important issues of site suitability early in the process and a clear program should be established to address these issues

Hydrological and geochemical investigation on the volcanic rock and gneissic rock area

Energy Technology Data Exchange (ETDEWEB)

Koh, Yong Kwon; Jeong, Chan Ho; Ryu, Kun Seok; Kim, Byoung Yeop; Park, Hyung Kun; Yu, Sang Woo; Jang, Hyu Kun; Lee, Suk Chi; Choi, Ki Young; Jeon, Hyu Woong; Kim, Do Hyoung [Daejong University, Daejeon (Korea, Republic of)

2010-01-15

The purpose of this study is to supply the basic data and optimum study site among volcanic rock area and gneissic rock area for high-level radioactive waste disposal. For this purpose, geological, hydrogeological and geochemical data from previously published literatures were collected and analyzed. In this study, we selected 36 volcanic rock sites and 26 gneissic sites as the candidate sites for high level radwaste disposal. Finally, for four sites(M-1, M-13, V-1 and V-13 sites) were selected as the study sites. The geochemical characteristics of groundwaters of each study site were statistically analyzed. The nitrate contamination and the sea water mixing will be important factors on the assessment of behaviour of radionuclides under groundwater environment. From the deep geothermal study, alkaline and sodium-bicarbonate chemical environment, and sea water mixing should be considered as the key factors for the deep disposal of high-level radioactive waste

Actinorhizal Alder Phytostabilization Alters Microbial Community Dynamics in Gold Mine Waste Rock from Northern Quebec: A Greenhouse Study.

Directory of Open Access Journals (Sweden)

Katrina L Callender

Full Text Available Phytotechnologies are rapidly replacing conventional ex-situ remediation techniques as they have the added benefit of restoring aesthetic value, important in the reclamation of mine sites. Alders are pioneer species that can tolerate and proliferate in nutrient-poor, contaminated environments, largely due to symbiotic root associations with the N2-fixing bacteria, Frankia and ectomycorrhizal (ECM fungi. In this study, we investigated the growth of two Frankia-inoculated (actinorhizal alder species, A. crispa and A. glutinosa, in gold mine waste rock from northern Quebec. Alder species had similar survival rates and positively impacted soil quality and physico-chemical properties in similar ways, restoring soil pH to neutrality and reducing extractable metals up to two-fold, while not hyperaccumulating them into above-ground plant biomass. A. glutinosa outperformed A. crispa in terms of growth, as estimated by the seedling volume index (SVI, and root length. Pyrosequencing of the bacterial 16S rRNA gene for bacteria and the ribosomal internal transcribed spacer (ITS region for fungi provided a comprehensive, direct characterization of microbial communities in gold mine waste rock and fine tailings. Plant- and treatment-specific shifts in soil microbial community compositions were observed in planted mine residues. Shannon diversity and the abundance of microbes involved in key ecosystem processes such as contaminant degradation (Sphingomonas, Sphingobium and Pseudomonas, metal sequestration (Brevundimonas and Caulobacter and N2-fixation (Azotobacter, Mesorhizobium, Rhizobium and Pseudomonas increased over time, i.e., as plants established in mine waste rock. Acetate mineralization and most probable number (MPN assays showed that revegetation positively stimulated both bulk and rhizosphere communities, increasing microbial density (biomass increase of 2 orders of magnitude and mineralization (five-fold. Genomic techniques proved useful in

Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

Science.gov (United States)

Swain, Ranjita; Bhima Rao, R.

2018-04-01

In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

Application of Response Surface Methodology on Leaching of Iron from Partially Laterised Khondalite Rocks: A Bauxite Mining Waste

Science.gov (United States)

Swain, Ranjita; Bhima Rao, R.

2017-08-01

In the present investigation, response surface methodology (RSM) is used for a quadratic model that continuously controls the process parameters. This model is used to optimize the removal of iron oxide from Partially Laterised Khondalite (PLK) rocks which is influenced by several independent variables namely acid concentration, time and temperature. Second order response functions are produced for leaching of iron oxide from PLK rocks-a bauxite mining waste. In RSM, Box-Behnken design is used for the process optimization to achieve maximum removal of iron oxide. The influence of the process variables of leaching of iron oxide is presented in the form of 3-D response graphs. The results of this investigation reveals that 3 M hydrochloric acid concentration, 240 min time and 373 K temperature are found to be the best conditions for removal of 99% Fe2O3. The product obtain at this condition contain 80% brightness which is suitable for ceramic and filler industry applications. The novelity of the work is that the waste can be a value added product after suitable physical beneficiation and chemical treatment.

Transferability of geodata from European to Canadian (Ontario) sedimentary rocks to study gas transport from nuclear wastes repositories

International Nuclear Information System (INIS)

Fall, M.; Ghafari, H.; Evgin, E.; Nguyen, T.S.

2010-01-01

Document available in extended abstract form only. A deep geological repository (DGR) for low and intermediate level waste in southern Ontario is currently proposed, at a depth of approximately 680 m in an argillaceous limestone formation (Cobourg Limestone) overlain by 200 m of low permeability shale (Ordovician Shale). Significant quantities of gas could be generated in the aforementioned DGR from several processes (e.g., degradation of waste forms, corrosion of waste containers). The accumulation and release of such gases from the repository system may affect a number of processes that influence its long-term safety. Consequently, safety assessments of the proposed DGR need to be supported by a solid understanding of the main mechanisms associated with gas generation and migration and the capability to mathematically model those mechanisms. The development of those mathematical models would usually require the consideration of complex coupled thermo-hydro-mechanical- chemical (THMC) processes. A research program is being conducted in the Department of Civil Engineering of the University of Ottawa in collaboration with the Canadian Nuclear Safety Commission (CNSC) to model the coupled THMC processes associated with gas migration and their impacts on the safety of DGR in southern Ontario. The development and validation of such model as well as the assessment of the impact of gas migration need the acquisition of sufficient amount of (good quality) data on the geomechanical, geochemical, hydraulic, thermal properties of the sedimentary rocks in Southern Ontario as well as relevant gas transport parameters, such as gas entry pressure, Klinkenberg effect, intrinsic permeability, capillary pressure-water saturation relationship. During the past fifteen years, several laboratory and field investigations have been conducted in several countries to acquire geo-data to study and model the THMC processes associated with gas migration in DGR in sedimentary rocks. However

Potential host media for a high-level waste repository

Energy Technology Data Exchange (ETDEWEB)

Hustrulid, W

1982-01-01

Earlier studies of burial of radioactive wastes in geologic repositories had concentrated on salt formations for well-publicized reasons. However, under the Carter administration, significant changes were made in the US nuclear waste management program. Changes which were made were: (1) expansion of the number of rock types under consideration; (2) adoption of the multiple-barrier approach to waste containment; (3) additional requirements for waste retrieval; and (4) new criteria proposed by the Nuclear Regulatory Commission for the isolation of high-level waste in geologic repositories. Results of the studies of different types of rocks as repository sites are summarized herein. It is concluded that each generic rock type has certain advantages and disadvantages when considered from various aspects of the waste disposal problem and that characteristics of rocks are so varied that a most favorable or least favorable rock type cannot be easily identified. This lack of definitive characteristics of rocks makes site selection and good engineering barriers very important for containment of the wastes. (BLM)

Radioactive waste repositories in hard rock aquifers--hydrodynamic aspects

International Nuclear Information System (INIS)

Thunvik, R.; Braester, C.

1984-01-01

A mathematical model for mass and heat flow and a computer program have been developed to demonstrate the effect of heat released from a hypothetical radioactive waste repository on the groundwater flow regime. The model, based on the continuum approach, conceptualizes the fracture pattern and the solid blocks as two overlapping continua and consists of a set of coupled nonlinear partial differential equations. The general form of the model is three-dimensional and can treat the fluid and rock either as two separate media with a quasi-steady exchange of heat between them or as a single equivalent medium with instantaneous thermal equilibrium. Numerical solutions have been obtained by the Galerkin finite element method. Examples have been presented for topographically different locations of the repository: below a horizontal ground surface, below a hill crest, below a hillside, and close to major fractures. The effects of constant permeability and porosity or downward decreasing with depth as well as the effect of anisotropic permeability have been investigated. Solutions include the velocity field, path lines, and traveling times of water particles passing the repository and the temperature distribution. The examples have been worked out for a two-dimensional flow domain, assuming that instantaneous thermal equilibrium takes place. This assumption was found to be justified by the relatively low flow velocities that occurred in the examples. Except for the location close to a major draining fracture, heat released from the radioactive waste repository may have a significant influence on the flow regime around the repository

Analysis of hydraulic gradients across the host rock at the proposed Texas Panhandle nuclear-waste repository site

International Nuclear Information System (INIS)

Bair, E.S.

1987-01-01

Analysis of the direction of ground-water flow across the host rock at the proposed high-level nuclear-waste repository site in Deaf Smith County, Texas, is complicated by vertical and lateral changes in the density of formation fluids in the various hydrogeologic units that overlie and underlie the proposed host rock. Because the concept of hydraulic head is not valid when evaluating vertical hydraulic gradients in a variably-density flow system, other methods were used to determine the direction and magnitude of vertical hydraulic gradients at the proposed site where the specific gravity of formation fluids varies between 1.00 and 1.28. The direction of ground-water flow across the proposed host rock, an 80-foot-thick salt bed in the Lower San Andres Formation, was determined by calculating vertical hydraulic gradients based on formation pressure and fluid density data, and by analysis of pressure-depth diagrams. Based on data from the vicinity of the proposed site, both methods indicate the potential for downflow across the host rock. Downflow or predominantly horizontal flow is considered a favorable prewaste emplacement condition because it prolongs the travel time to the biosphere of any naturally or accidentally released radionuclides

Radiant energy dissipation during final storage of high-level radioactive waste in rock salt

International Nuclear Information System (INIS)

Ramthun, H.

1981-08-01

A final disposal concept is assumed where the high-active waste from 1400 t of uranium, remaining after conditioning, is solidified in borosilicate glass and distributed in 1.760 waste casks. These containers 1.2 m in height and 0.3 m in diameter are to be buried 10 years after the fuel is removed from the reactor in the 300 m deep boreholes of a salt dome. For this design the mean absorbed dose rates are calculated in the glass die (3.9 Gy/s), the steel mantle (0.26 Gy/s) and in the salt rock (0.12 Gy/s at a distance of 1 cm and 0.034 Gy/s at a distance of 9 cm from the container surface) valid at the beginning of disposal. The risk involved with these amounts of stored lattice energy is shortly discussed. (orig.) [de

Produção de mudas de tomateiro em substratos contendo fibra de coco e pó de rocha Tomato seedlings production using substrates with coconut fiber and rock waste

Directory of Open Access Journals (Sweden)

Regynaldo A Sampaio

2008-12-01

Full Text Available Com o objetivo de avaliar proporções dos resíduos fibra de coco (FC e pó de rocha de granito (RG como substratos na produção de mudas de tomateiro, cultivar Kada Gigante, realizou-se um experimento em casa de vegetação na UFMG-ICA. Foi utilizado o delineamento experimental em blocos ao acaso, com quatro repetições. Os tratamentos foram constituídos por uma testemunha e seis proporções de fibra de coco (FC e pó de rocha de granito (RG: T1 - Substrato comercial Hortimix®; T2 - 0% FC + 100% RG; T3 - 20% FC + 80% RG; T4 - 40% FC + 60% RG; T5 - 60% FC + 40% RG; T6 - 80% FC + 20% RG; T7 - 100% FC + 0% RG. O cultivo foi feito em bandeja de poliestireno expandido com células de 3,5 x 3,5 x 5,0 cm. Foram avaliados o diâmetro do coleto, a altura da planta, o índice de velocidade de emergência, a percentagem de emergência e a massa fresca e seca da parte aérea e da raiz. Em praticamente todas as características avaliadas o substrato comercial foi superior aos substratos contendo fibra de coco e pó de rocha. Considerando-se apenas os substratos contendo fibra de coco e pó de rocha, as mudas com melhores características foram obtidas com a mistura de aproximadamente 70% em volume de fibra de coco.A greenhouse experiment was carried out to evaluate the ratio of coconut fiber and rock waste, in the tomato seedling production (cultivar Kada Gigante, in Montes Claros, Brazil. The experimental design was of randomized complete blocks with four replicates. The treatments were composed of a control and six ratios of coconut fiber (FC and rock waste (RG: T1 - Commercial Substrate Hortimix®; T2 - 0% FC + 100% RG; T3 - 20% FC + 80% RG; T4 - 40% FC + 60% RG; T5 - 60% FC + 40% RG; T6 - 80% FC + 20% RG; T7 - 100% FC + 0% RG. The cultivation was done in polystyrene trays with cells of 3.5 x 3.5 x 5,0 cm. Stem diameter, seedling height, emergency speed index, emergency percentage, root and aerial part of fresh and dry matter were evaluated. In

Lithology, microstructures, fluid inclusions, and geochemistry of rock salt and of the cap-rock contact in Oakwood Dome, East Texas: significance for nuclear waste storage. Report of investigations No. 120

International Nuclear Information System (INIS)

Dix, O.R.; Jackson, M.P.A.

1982-01-01

Oakwood salt dome in Leon and Freestone Counties, Texas, has a core composed of a diapiric salt stock at a depth of 355 m. A vertical borehole in the center of the salt stock yielded 57.3 m of continuous rock-salt core overlain by 137 m of anhydrite-calcite cap rock. The lower 55.3 m of rock salt exhibits a strong, penetrative schistosity and parallel cleavage dipping at 30 to 40 0 and more than 60 variably dipping layers of disseminated anhydrite. Anhydrite constitutes 1.3 +- 0.7 percent of the rock-salt core. The upper 2 m of rock salt is unfoliated, comprising a lower 1.4-m interval of medium-grained granoblastic rock salt and an upper 0.6-m interval of coarse-grained granoblastic rock salt. An abrupt, cavity-free contact separates rock salt from laminated cap rock consisting of granoblastic-polygonal anhydrite virtually devoid of halite or pore space. Microstructures and concentration gradients of fluid inclusions suggest that the unfoliated rock salt at the crest of the salt stock was once strongly foliated, but that this fabric was destroyed by solid-state recrystallization. Downward movement of brine from the rock-salt - cap-rock contact was apparently accompanied by two recrystallization fronts. Dissolution of halite at the contact released disseminated anhydrite that presumably accumulated as sand on the floor of the dissolution cavity. Renewed rise of the salt stock closed the cavity, and the anhydrite sand was accreted against the base of the cap rock. Much, if not all, of the lamination in the 80 m of anhydrite cap rock may result from cycles of dissolution, recrystallization, and upward movement in the salt stock, followed by accretion of anhydrite residuum as laminae against the base of the cap rock. These processes, which are strongly influenced by fluids, act both to breach waste repositories and to geologically isolate them

Characterizing fractured plutonic rocks of the Canadian shield for deep geological disposal of Canada's radioactive wastes

International Nuclear Information System (INIS)

Lodha, G.S.; Davison, C.C.; Gascoyne, M.

1998-01-01

Since 1978 AECL has been investigating plutonic rocks of the Canadian Shield as a potential medium for the disposal of Canada's nuclear fuel waste. During the last two years this study has been continued as part of Ontario Hydro's used fuel disposal program. Methods have been developed for characterizing the geotechnical conditions at the regional scale of the Canadian Shield as well as for characterizing conditions at the site scale and the very near-field scale needed for locating and designing disposal vault rooms and waste emplacement areas. The Whiteshell Research Area (WRA) and the Underground Research Laboratory (URL) in southeastern Manitoba have been extensively used to develop and demonstrate the different scales of characterization methods. At the regional scale, airborne magnetic and electromagnetic surveys combined with LANDSAT 5 and surface gravity survey data have been helpful in identifying boundaries of the plutonic rocks , overburden thicknesses, major lineaments that might be geological structures, lithological contacts and depths of the batholiths. Surface geological mapping of exposed rock outcrops, combined with surface VLF/EM, radar and seismic reflection surveys were useful in identifying the orientation and depth continuity of low-dipping fracture zones beneath rock outcrops to a depth of 500 to 1000 m. The surface time-domain EM method has provided encouraging results for identifying the depth of highly saline pore waters. The regional site scale investigations at the WRA included the drilling of twenty deep boreholes (> 500 m) at seven separate study areas. Geological core logging combined with borehole geophysical logging, TV/ATV logging, flowmeter logging and full waveform sonic logging in these boreholes helped to confirm the location of hydro geologically important fractures, orient cores and infer the relative permeability of some fracture zones. Single-hole radar and crosshole seismic tomography surveys were useful to establish the

An integrated approach to isotopic study of crystalline rock for a high-level waste repository: Area phase

International Nuclear Information System (INIS)

Gilbert, L.A.

1986-01-01

An integrated approach to assessing isotopic systems in crystalline rock is planned for area phase studies. This approach combines radiogenic isotope systems with petrography in order to characterize potential crystalline repository media. The coeval use of selected isotope systems will minimize the limitations of each method and provide intensive parameters yielding data on alteration timing, secondary mineral formation, temperature history, and radionuclide species migration. Isotope systems will be selected in order to measure differences in sensitivity to thermal disturbances and mobility due to fluid interaction. Comparative evaluation of isotope pair behavior may be used in combination with mineral versus whole-rock dates to provide data on heating and mobilization of alkali elements, lanthanides, and gases, caused by future introduction of waste

Development of waste packages for tuff

International Nuclear Information System (INIS)

Rothman, A.J.

1982-01-01

The objective of this program is to develop nuclear waste packages that meet the Nuclear Regulatory Commission's requirements for a licensed repository in tuff at the Nevada Test Site. Selected accomplishments for FY82 are: (1) Selection, collection of rock, and characterization of suitable outcrops (for lab experiments); (2) Rock-water interactions (Bullfrog Tuff); (3) Corrosion tests of ferrous metals; (4) Thermal modeling of waste package in host rock; (5) Preliminary fabrication tests of alternate backfills (crushed tuff); (6) Reviewed Westinghouse conceptual waste package designs for tuff and began modification for unsaturated zone; and (7) Waste Package Codes (BARIER and WAPPA) now running on our computer. Brief discussions are presented for rock-water interactions, corrosion tests of ferrous metals, and thermal and radionuclide migration modelling

A structural behavior study of rock caverns considering the effects of discontinuities

International Nuclear Information System (INIS)

Kim, Jhin Wung; Kim, Sun Hoon; Seo, Jeong Moon; Choi, Kyu Seop; Kim, Dae Hong; Lee, Kyung Jin; Choi, In Gil; Lee, Dong Yong

1990-06-01

The objective of this study is to understand the effects of discontinuities within rock masses on the structural behavior of underground rock caverns for radioactive waste disposal, and then develop a computer program for the structural analysis of rock caverns considering these effect of discontinuities. The behavior of rock masses, such as strength, deformation modes, ect., is very difficult to predict because discontinuities in the form of microcracks or joints are randomly distributed within rock masses. Discontinuties existing around the rock cavern for underground radioactive waste disposal may become the main transport pathways of radionuclides, and reduce the strength of rock masses eventually causing the rock cavern structure unstable. Therefore, a comprehensive understanding of the mechanical properties and behavior of discontinuous rock masses and an improvement of structural analysis methods are essential in order to understand the behavior of underground rock cavern structures properly in order to design safe and economic understanding the behavior of discontinuous rock masses is essential. Therfore, this study includes literature review on mechanical properties of and computational models for discontinuous rock masses, and on structures. Then, bases on the engineering judgement a suitable selection and slight modifications on computational models and analysis methods have been made before developing the structural analysis computer program for underground radioactive waste disposal structures. (author)

Diffusive transport and reaction in clay rocks: A storage (nuclear waste, CO2, H2), energy (shale gas) and water quality issue

Science.gov (United States)

Charlet, Laurent; Alt-Epping, Peter; Wersin, Paul; Gilbert, Benjamin

2017-08-01

Clay rocks are low permeability sedimentary formations that provide records of Earth history, influence the quality of water resources, and that are increasingly used for the extraction or storage of energy resources and the sequestration of waste materials. Informed use of clay rock formations to achieve low-carbon or carbon-free energy goals requires the ability to predict the rates of diffusive transport processes for chemically diverse dissolved and gaseous species over periods up to thousands of years. We survey the composition, properties and uses of clay rock and summarize fundamental science challenges in developing confident conceptual and quantitative gas and solute transport models.

Environmental remediation of the Wismut legacy and utilization of the reclaimed areas, waste rock piles and tailings ponds

International Nuclear Information System (INIS)

Hagen, M.; Jakubick, A.T.

2006-01-01

Between 1945 and reunification (1989) of Germany more than 232 000 t of U 3 O 8 has been produced in Saxony and Thuringia, East Germany. This affected an area of approximately 100 km 2 and left behind an extensive legacy of contaminated operations areas, underground and open pit mines, waste rock piles and tailings ponds. Following reunification, DM 13 billion (Euro 6.6 billion) were committed (and later revised to Euro 6.2 billion) to remediation of the liabilities and the government owned corporation, Wismut GmbH entrusted with the implementation of the Environmental Remediation (ER) of the liabilities. The prime goal of the ER Project follows from the legal requirements to abate health risks, mitigate existing and prevent future environmental damages. During the investigations and assessment of risks, development of remediation concepts, adoption of suitable technologies and work procedures as well as physical implementation of the remedial measures extensive use was made of international (mostly US and Canadian) ER experience. The extent of remedial measures was based on object-specific Environmental Assessments rather than on uniformly applied health/environmental standards. The ER workflow is more an iterative process than a linear succession of tasks, such as common for civil engineering projects. The internal (technical) parts of the problems were partly resolved by using Conceptual Site Models (CSM) for selection and prioritization of remedial measures. Reclamation of the waste rock piles is by covering in situ, relocation to a central pile or backfilling into an open pit. The backfilling of the open pit at Ronneburg with acid generating waste rock has been optimized from a geochemical point of view. For tailings ponds reclamation in form of dry landforms is being followed. To increase release (and reuse) of scrap metal from demolition, a fast and reliable method of discrimination of the non-contaminated metal has been developed. The flooding of

Mine Waste Disposal and Managements

Energy Technology Data Exchange (ETDEWEB)

Cheong, Young-Wook; Min, Jeong-Sik; Kwon, Kwang-Soo [Korea Institute of Geology Mining and Materials, Taejon (KR)] (and others)

1999-12-01

This research project deals with: Analysis and characterization of mine waste piles or tailings impoundment abandoned in mining areas; Survey of mining environmental pollution from mine waste impounds; Modelling of pollutants in groundwater around tailings impoundment; Demonstration of acid rock drainage from coal mine waste rock piles and experiment of seeding on waste rock surface; Development of a liner using tailings. Most of mine wastes are deposited on natural ground without artificial liners and capping for preventing contamination of groundwater around mine waste piles or containments. In case of some mine waste piles or containments, pollutants have been released to the environment, and several constituents in drainage exceed the limit of discharge from landfill site. Metals found in drainage exist in exchangeable fraction in waste rock and tailings. This means that if when it rains to mine waste containments, mine wastes can be pollutant to the environment by release of acidity and metals. As a result of simulation for hydraulic potentials and groundwater flow paths within the tailings, the simulated travel paths correlated well with the observed contaminant distribution. The plum disperse, both longitudinal and transverse dimensions, with time. Therefore liner system is a very important component in tailings containment system. As experimental results of liner development using tailings, tailings mixed with some portion of resin or cement may be used for liner because tailings with some additives have a very low hydraulic conductivity. (author). 39 refs.

Review of potential host rocks for radioactive waste disposal in the southeast United States-Southern Piedmont subregion

International Nuclear Information System (INIS)

1980-10-01

A literature study was conducted on the geology of the Southern Piedmont province in the states of Maryland, Virginia, North Carolina, South Carolina, and Georgia. The purpose was to identify geologic areas potentially suitable for containment of a repository for the long-term isolation of solidified radioactive waste. The crystalline rocks of the Southern Piedmont province range in age from Precambrian to Paleozoic, and are predominantly slates, phyllites, argillites, schists, metavolcanics, gneisses, gabbros, and granites. These rock units were classified as either favorable, potentially favorable, or unfavorable as potential study areas based on an evaluation of the geologic, hydrologic, and geotechnical characteristics. No socio-economic factors were considered. Rocks subjected to multiple periods of deformation and metamorphism, or described as highly fractured, or of limited areal extent were generally ranked as unfavorable. Potentially favorable rocks are primarily the high-grade metamorphic gneisses and granites. Sixteen areas were classified as being favorable for additional study. These areas are primarily large igneous granite plutons as follows: the Petersburg granite in Virginia; the Rolesville-Castallia, Churchland, and Landis plutons in North Carolina; the Liberty Hill, Winnsboro, and Ogden plutons in South Carolina; and the Siloam, Elberton, and six unnamed granite plutons in Georgia

Comprenhensive Program of Engineering and Geologic Surveys for Designing and Constructing Radioactive Waste Storage Facilities in Hard Rock Massifs

International Nuclear Information System (INIS)

Gupalo, T.; Milovidov, V.; Prokopoca, O.; Jardine, L.

2002-01-01

Geological, geophysical, and engineering-geological research conducted at the 'Yeniseisky' site obtained data on climatic, geomorphologic, geological conditions, structure and properties of composing rock, and conditions of underground water recharge and discharge. These results provide suficient information to make an estimate of the suitability of locating a radioactive waste (RW) underground isolation facility at the Nizhnekansky granitoid massif.

Production Of Bio fuel Starter From Biomass Waste Using Rocking Kiln Fluidized Bed System

International Nuclear Information System (INIS)

Mohamad Azman Che Mat Isa; Muhd Noor Muhd Yunus; Zulkafli Ghazali; Mohd Zaid Mohamed; Phongsakorn, P.T.; Mohamad Puad Abu

2014-01-01

The biggest biomass source in Malaysia comes from oil palm industry. According to the statistic in 2010, Malaysia produced 40 million tones per year of biomass of which 30 million tones of biomass originated from the oil palm industries. The biomass waste such as palm kernel shell can be used to produce activated carbon and bio fuel starter. A new type of rotary kiln, called Rocking Kiln Fluidized Bed (RKFB) was developed in Nuclear Malaysia to utilize the large amount of the biomass to produce high value added products. This system is capable to process biomass with complete combustion to produce bio fuel starter. With this system, the produced charcoal has calorific value, 33MJ/ kg that is better than bituminous coal with calorific value, 25-30 MJ/ kg. In this research, the charcoals produced were further used to produce the bio fuel starter. This paper will elaborate the experimental set-up of the Rocking Kiln Fluidized Bed (RKFB) for bio fuel starter production and the quality of the produced bio fuel starter. (author)

Immobilisation of high level nuclear reactor wastes in SYNROC

Energy Technology Data Exchange (ETDEWEB)

Ringwood, A E; Kesson, S E; Ware, N G; Hibberson, W; Major, A [Australian National Univ., Canberra. Inst. of Advanced Studies

1979-03-15

It is stated that the elements occurring in high-level nuclear reactor wastes can be safely immobilised by incorporating them within the crystal lattices of the constituent minerals of a synthetic rock (SYNROC). The preferred form of SYNROC can accept up to 20% of high level waste calcine to form dilute solid solutions. The constituent minerals, or close structural analogues, have survived in a wide range of geochemical environments for periods of 20 to 2,000 Myr whilst immobilising the same elements present in nuclear wastes. SYNROC is unaffected by leaching for 24 hours in pure water or 10 wt % NaCl solution at high temperatures and pressure whereas borosilicate glasses completely decompose in a few hours in much less severe hydrothermal conditions. The combination of these leaching results with the geological evidence of long-term stability indicates that SYNROC would be vastly superior to glass in its capacity to safely immobilise nuclear wastes, when buried in a suitable geological repository. A dense, compact, mechanically strong form of SYNROC suitable for geological disposal can be produced by a process as economical as that which incorporates radioactive waste in borosilicate glasses.

Requirements for a long-term safety certification for chemotoxic substances stored in a final storage facility for high radioactive and heat-generating radioactive waste in rock salt formations

International Nuclear Information System (INIS)

Tholen, M.; Hippler, J.; Herzog, C.

2007-01-01

Within the scope of a project funded by the German Federal Ministry of Economics and Technology (Bundesministerium fuer Wirtschaft und Technologie, BMWi), a safety certification concept for a future permanent final storage for high radioactive and heat-generating radioactive waste (HAW disposal facility) in rock salt formations is being prepared. For a reference concept, compliance with safety requirements in regard to operational safety as well as radiological and non-radiological protection objectives related to long-term safety, including ground water protection, will be evaluated. This paper deals with the requirements for a long-term safety certification for the purpose of protecting ground water from chemotoxic substances. In particular, longterm safety certifications for the permanent disposal of radioactive waste in a HAW disposal facility in rock salt formations and for the dumping of hazardous waste in underground storage facilities in rock salt formations are first discussed, followed by an evaluation as to whether these methods can be applied to the long-term safety certification for chemotoxic substances. The authors find it advisable to apply the long-term safety certification for underground storage facilities to the long-term safety certification for chemotoxic substances stored in a HAW disposal facility in rock salt formations. In conclusion, a corresponding certification concept is introduced. (orig.)

Rock disposal problems identified

Energy Technology Data Exchange (ETDEWEB)

Knox, R

1978-06-01

Mathematical models are the only way of examining the return of radioactivity from nuclear waste to the environment over long periods of time. Work in Britain has helped identify areas where more basic data is required, but initial results look very promising for final disposal of high level waste in hard rock repositories. A report by the National Radiological Protection Board of a recent study, is examined.

Programme of research into the disposal of radioactive waste into geological formations. Studies on crystalline rock. Contract 059-78-1 WASUK. Final report: General studies of physical properties

International Nuclear Information System (INIS)

1981-11-01

This report covers the following topics: groundwater dating; heat transfer and associated thermal studies (in-situ heat transfer experiment; thermal rock and fluid mechanics studies; thermal convection; hydraulic permeability experiments; laboratory studies); corrosion and chemical compatibility studies (field and laboratory corrosion studies; waste - rock interactions). (U.K.)

Package materials, waste form

International Nuclear Information System (INIS)

Anon.

1980-01-01

The schedules for waste package development for the various host rocks were presented. The waste form subtask activities were reviewed, with the papers focusing on high-level waste, transuranic waste, and spent fuel. The following ten papers were presented: (1) Waste Package Development Approach; (2) Borosilicate Glass as a Matrix for Savannah River Plant Waste; (3) Development of Alternative High-Level Waste Forms; (4) Overview of the Transuranic Waste Management Program; (5) Assessment of the Impacts of Spent Fuel Disassembly - Alternatives on the Nuclear Waste Isolation System; (6) Reactions of Spent Fuel and Reprocessing Waste Forms with Water in the Presence of Basalt; (7) Spent Fuel Stabilizer Screening Studies; (8) Chemical Interactions of Shale Rock, Prototype Waste Forms, and Prototype Canister Metals in a Simulated Wet Repository Environment; (9) Impact of Fission Gas and Volatiles on Spent Fuel During Geologic Disposal; and (10) Spent Fuel Assembly Decay Heat Measurement and Analysis

Drill-back studies examine fractured, heated rock

International Nuclear Information System (INIS)

Wollenberg, H.A.; Flexser, S.; Myer, L.R.

1990-01-01

To investigate the effects of heating on the mineralogical, geochemical, and mechanical properties of rock by high-level radioactive waste, cores are being examined from holes penetrating locations where electric heaters simulated the presence of a waste canister, and from holes penetration natural hydrothermal systems. Results to date indicate the localized mobility and deposition of uranium in an open fracture in heated granitic rock, the mobility of U in a breccia zone in an active hydrothermal system in tuff, and the presence of U in relatively high concentration in fracture-lining material in tuff. Mechanical -- property studies indicate that differences in compressional- and shear-wave parameters between heated and less heated rock can be attributed to differences in the density of microcracks. Emphasis has shifted from initial studies of granitic rock at Stripa, Sweden to current investigations of welded tuff at the Nevada Test Site. 7 refs., 8 figs

Unsaturated flow and transport through fractured rock related to high-level waste repositories

International Nuclear Information System (INIS)

Evans, D.D.; Rasmussen, T.C.

1991-01-01

Research results are summarized for a US Nuclear Regulatory Commission contract with the University of Arizona focusing on field and laboratory methods for characterizing unsaturated fluid flow and solute transport related to high-level radioactive waste repositories. Characterization activities are presented for the Apache Leap Tuff field site. The field site is located in unsaturated, fractured tuff in central Arizona. Hydraulic, pneumatic, and thermal characteristics of the tuff are summarized, along with methodologies employed to monitor and sample hydrologic and geochemical processes at the field site. Thermohydrologic experiments are reported which provide laboratory and field data related to the effects conditions and flow and transport in unsaturated, fractured rock. 29 refs., 17 figs., 21 tabs

A review and synthesis of international proposals for the disposal of high-level radioactive wastes into crystalline rock formations

International Nuclear Information System (INIS)

1981-05-01

Examination of the broad range of international concepts for the disposal of high-level radioactive wastes into crystalline rock formations has indicated that systems based upon solid waste units provide the greatest degree of engineering control and security. Three particular disposal concepts are considered worthy of detailed evaluation. In order of priority these are:-tunnel networks with 'in-floor' waste emplacement; matrix of vertical emplacement holes drilled from the surface; tunnel networks with 'in-room' waste emplacement. A review of the international literature has shown that at least ten countries have embarked upon study programmes, but only five have developed detailed conceptual design proposals. These are:- Canada, France, Sweden, the United Kingdom, and the United States. Differing economic, environmental, historical and political circumstances have influenced the pattern of international studies and, to the uninitiated, these factors may obscure some of the relevant technical considerations. Nevertheless, a broad technical concensus is apparent in that all countries currently favour tunnel networks with 'in-floor' waste emplacement. The subject is discussed in detail. (author)

Characterization and evaluation of sites for deep geological disposal of radioactive waste in fractured rocks. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-09-01

The third Aespoe International Seminar was organised by SKB to assess the state of the art in characterisation and evaluation of sites for deep geological disposal of radioactive waste in fractured rocks. Site characterisation and evaluation are important elements for determining the site suitability and long-term safety of a geological repository for radioactive waste disposal. Characterisation work also provides vital information for the design of the underground facility and the engineered barrier system that will contain the waste. The aim of the seminar was to provide a comprehensive assessment of the current know-how on this topic based on world-wide experience from more than 20 years of characterisation and evaluation work. The seminar, which was held at the Aespoe Hard Rock Laboratory was attended by 72 scientists from 10 different countries. The program was divided into four sessions of which two were run in parallel. A total of 38 oral and 5 poster presentations were given at the seminar. The presentations gave a comprehensive summary of recently completed and current work on site characterisation, modelling and application in performance assessments. The results presented at the seminar generally show that significant progress has been made in this field during the last decade. New characterisation techniques have become available, strategies for site investigations have developed further, and model concepts and codes have reached new levels of refinement. Data obtained from site characterisation have also successfully been applied in several site specific performance assessments. The seminar clearly showed that there is a solid scientific basis for assessing the suitability of sites for actual repositories based on currently available site characterisation technology and modelling capabilities. Separate abstracts have been prepared for 38 of the presentations

Flow behavior and mobility of contaminated waste rock materials in the abandoned Imgi mine in Korea

Science.gov (United States)

Jeong, S. W.; Wu, Y.-H.; Cho, Y. C.; Ji, S. W.

2018-01-01

Incomplete mine reclamation can cause ecological and environmental impacts. This paper focuses on the geotechnical and rheological characteristics of waste rock materials, which are mainly composed of sand-size particles, potentially resulting in mass movement (e.g., slide or flow) and extensive acid mine drainage. To examine the potential for contaminant mobilization resulting from physicochemical processes in abandoned mines, a series of scenario-based debris flow simulations was conducted using Debris-2D to identify different hazard scenarios and volumes. The flow behavior of waste rock materials was examined using a ball-measuring rheometric apparatus, which can be adapted for large particle samples, such as debris flow. Bingham yield stresses determined in controlled shear rate mode were used as an input parameter in the debris flow modeling. The yield stresses ranged from 100 to 1000 Pa for shear rates ranging from 10- 5 to 102 s- 1. The results demonstrated that the lowest yield stress could result in high mobility of debris flow (e.g., runout distance > 700 m from the source area for 60 s); consequently, the material contaminants may easily reach the confluence of the Suyoung River through a mountain stream. When a fast slide or debris flow occurs at or near an abandoned mine area, it may result in extremely dynamic and destructive geomorphological changes. Even for the highest yield stress of debris flow simulation (i.e., τy = 2000 Pa), the released debris could flow into the mountain stream; therefore, people living near abandoned mines may become exposed to water pollution throughout the day. To maintain safety at and near abandoned mines, the physicochemical properties of waste materials should be monitored, and proper mitigation measures post-mining should be considered in terms of both their physical damage and chemical pollution potential.

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

International Nuclear Information System (INIS)

Unuofin, F.O.; Mnkeni, P.N.S.

2014-01-01

Highlights: • Vermidegradation of RP-enriched waste mixtures is dependent on E. fetida stocking density. • A stocking density of 12.5 g-worms kg -1 resulted in highly humified vermicomposts. • P release from RP-enriched waste vermicomposts increases with E. fetida stocking density. • RP-enriched waste vermicomposts had no inhibitory effect on seed germination. - Abstract: Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg −1 dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg −1 resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg −1 feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered

Optimization of Eisenia fetida stocking density for the bioconversion of rock phosphate enriched cow dung–waste paper mixtures

Energy Technology Data Exchange (ETDEWEB)

Unuofin, F.O., E-mail: funmifrank2009@gmail.com; Mnkeni, P.N.S., E-mail: pmnkeni@ufh.ac.za

2014-11-15

Highlights: • Vermidegradation of RP-enriched waste mixtures is dependent on E. fetida stocking density. • A stocking density of 12.5 g-worms kg{sup -1} resulted in highly humified vermicomposts. • P release from RP-enriched waste vermicomposts increases with E. fetida stocking density. • RP-enriched waste vermicomposts had no inhibitory effect on seed germination. - Abstract: Vermitechnology is gaining recognition as an environmental friendly waste management strategy. Its successful implementation requires that the key operational parameters like earthworm stocking density be established for each target waste/waste mixture. One target waste mixture in South Africa is waste paper mixed with cow dung and rock phosphate (RP) for P enrichment. This study sought to establish optimal Eisenia fetida stocking density for maximum P release and rapid bioconversion of RP enriched cow dung–paper waste mixtures. E. fetida stocking densities of 0, 7.5, 12.5, 17.5 and 22.5 g-worms kg{sup −1} dry weight of cow dung–waste paper mixtures were evaluated. The stocking density of 12.5 g-worms kg{sup −1} resulted in the highest earthworm growth rate and humification of the RP enriched waste mixture as reflected by a C:N ratio of <12 and a humic acid/fulvic acid ratio of >1.9 in final vermicomposts. A germination test revealed that the resultant vermicompost had no inhibitory effect on the germination of tomato, carrot, and radish. Extractable P increased with stocking density up to 22.5 g-worm kg{sup −1} feedstock suggesting that for maximum P release from RP enriched wastes a high stocking density should be considered.

Heterogeneous redox conditions, arsenic mobility, and groundwater flow in a fractured-rock aquifer near a waste repository site in New Hampshire, USA

Science.gov (United States)

Anthropogenic sources of carbon from landfill or waste leachate can promote reductive dissolution of in situ arsenic (As) and enhance the mobility of As in groundwater. Groundwater from residential-supply wells in a fractured crystalline-rock aquifer adjacent to a Superfund site ...

Modeling fluid-rock interaction at Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Viani, B.E.; Bruton, C.J.

1992-08-01

Volcanic rocks at Yucca Mountain, Nevada aie being assessed for their suitability as a potential repository for high-level nuclear waste. Recent progress in modeling fluid-rock interactions, in particular the mineralogical and chemical changes that may accompany waste disposal at Yucca Mountain, will be reviewed in this publication. In Part 1 of this publication, ''Geochemical Modeling of Clinoptilolite-Water Interactions,'' solid-solution and cation-exchange models for the zeolite clinoptilolite are developed and compared to experimental and field observations. At Yucca Mountain, clinoptilolite which is found lining fractures and as a major component of zeolitized tuffs, is expected to play an important role in sequestering radionuclides that may escape from a potential nuclear waste repository. The solid-solution and ion-exchange models were evaluated by comparing predicted stabilities and exchangeable cation distributions of clinoptilolites with: (1) published binary exchange data; (2) compositions of coexisting clinoptilolites and formation waters at Yucca Mountain; (3) experimental sorption isotherms of Cs and Sr on zeolitized tuff, and (4) high temperature experimental data. Good agreement was found between predictions and expertmental data, especially for binary exchange and Cs and Sr sorption on clinoptilolite. Part 2 of this publication, ''Geochemical Simulation of Fluid-Rock Interactions at Yucca Mountain,'' describes preliminary numerical simulations of fluid-rock interactions at Yucca Mountain. The solid-solution model developed in the first part of the paper is used to evaluate the stability and composition of clinciptilolite and other minerals in the host rock under ambient conditions and after waste emplacement

Proceedings of the establishment conference of Professional Committee on Waste Underground Disposal of Chinese Society for Rock Mechanics and Engineering and the first academic seminar

International Nuclear Information System (INIS)

2006-07-01

Approved by the China Association for Science and Technology, Chinese Society for Rock Mechanics and Engineering newly established 'Professional Committee on Waste Underground Disposal'. The committee will organise the national and international academic exchange, and provide advice on discipline development, sustainable industrial development, environmental protection, etc.. This is the establishing conference of the professional committee, as well as the first academic seminar. The following topics on waste underground disposal are discussed: the theory, practice and exploration, project examples, new technologies and new methods. The contents include: waste disposal technology in the new century, the geological disposal of high level radioactive waste, LLW and ILW underground waste disposal, urban and industrial waste underground disposal, and etc.

Terminal storage of radioactive waste in geologic formations

International Nuclear Information System (INIS)

Lomenick, T.F.

1976-01-01

The principal aim of the National Waste Terminal Storage (NWTS) program is to develop pilot plants and, ultimately, repositories in several different rock formations in various parts of the country. Rocks such as salt, shale, limestone, granite, schists, and serpentinite may all qualify as host media for the disposition of radioactive wastes in the proper environments. In general, the only requirement for any rock formation or storage site is that it contain any emplaced wastes for so long as it takes for the radioactive materials to decay to innocuous levels. This requirement, though, is a formidable one as some of the wastes will remain active for periods of hundreds of thousands of years and the physical and chemical properties of rocks that govern circulating groundwater and hence containment, are difficult to determine and define. Nevertheless, there are many rock types and a host of areas throughout the country where conditions are promising for the development of waste repositories. Some of these are discussed below

Development of the Method of Bacterial Leaching of Metals out of Low-Grade Ores, Rocks, and Industrial Wastes Using Neutron Activation Analysis

CERN Document Server

Tsertsvadze, L A; Petriashvili, Sh G; Chutkerashvili, D G; Kirkesali, E I; Frontasyeva, M V; Pavlov, S S; Gundorina, S F

2001-01-01

The results of preliminary investigations aimed at the development of an economical and easy to apply technique of bacterial leaching of rare and valuable metals out of low-grade ores, complex composition ores, rocks, and industrial wastes in Georgia are discussed. The main groups of microbiological community of the peat suspension used in the experiments of bacterial leaching are investigated and the activity of particular microorganisms in the leaching of probes with different mineral compositions is assessed. The element composition of the primary and processed samples was investigated by the epithermal neutron activation analysis method and the enrichment/subtraction level is estimated for various elements. The efficiency of the developed technique to purify wastes, extract some scrace metals, and enrich ores or rocks in some elements, e.g. Au, U, Th, Cs, Sr, Rb, Sc, Zr, Hf, Ta, Gd, Er, Lu, Ce, etc., is demonstrated.

Modeling transient heat transfer in nuclear waste repositories.

Science.gov (United States)

Yang, Shaw-Yang; Yeh, Hund-Der

2009-09-30

The heat of high-level nuclear waste may be generated and released from a canister at final disposal sites. The waste heat may affect the engineering properties of waste canisters, buffers, and backfill material in the emplacement tunnel and the host rock. This study addresses the problem of the heat generated from the waste canister and analyzes the heat distribution between the buffer and the host rock, which is considered as a radial two-layer heat flux problem. A conceptual model is first constructed for the heat conduction in a nuclear waste repository and then mathematical equations are formulated for modeling heat flow distribution at repository sites. The Laplace transforms are employed to develop a solution for the temperature distributions in the buffer and the host rock in the Laplace domain, which is numerically inverted to the time-domain solution using the modified Crump method. The transient temperature distributions for both the single- and multi-borehole cases are simulated in the hypothetical geological repositories of nuclear waste. The results show that the temperature distributions in the thermal field are significantly affected by the decay heat of the waste canister, the thermal properties of the buffer and the host rock, the disposal spacing, and the thickness of the host rock at a nuclear waste repository.

Reference waste package environment report

International Nuclear Information System (INIS)

Glassley, W.E.

1986-01-01

One of three candidate repository sites for high-level radioactive waste packages is located at Yucca Mountain, Nevada, in rhyolitic tuff 700 to 1400 ft above the static water table. Calculations indicate that the package environment will experience a maximum temperature of ∼230 0 C at 9 years after emplacement. For the next 300 years the rock within 1 m of the waste packages will remain dehydrated. Preliminary results suggest that the waste package radiation field will have very little effect on the mechanical properties of the rock. Radiolysis products will have a negligible effect on the rock even after rehydration. Unfractured specimens of repository rock show no change in hydrologic characteristics during repeated dehydration-rehydration cycles. Fractured samples with initially high permeabilities show a striking permeability decrease during dehydration-rehydration cycling, which may be due to fracture healing via deposition of silica. Rock-water interaction studies demonstrate low and benign levels of anions and most cations. The development of sorptive secondary phases such as zeolites and clays suggests that anticipated rock-water interaction may produce beneficial changes in the package environment

Predictability of the evolution of hydrogeological and hydrogeochemical systems; geological disposal of nuclear waste in crystalline rocks

International Nuclear Information System (INIS)

Murphy, W.M.; Diodato, D.M.

2009-01-01

Confidence in long-term geologic isolation of high-level nuclear waste and spent nuclear fuel requires confidence in predictions of the evolution of hydrogeological and hydrogeochemical systems. Prediction of the evolution of hydrogeological and hydrogeochemical systems is based on scientific understanding of those systems in the present - an understanding that can be tested with data from the past. Crystalline rock settings that have been geologically stable for millions of years and longer offer the potential of predictable, long-term waste isolation. Confidence in predictions of geologic isolation of radioactive waste can measured by evaluating the extent to which those predictions and their underlying analyses are consistent with multiple independent lines of evidence identified in the geologic system being analysed, as well as with evidence identified in analogs to that geologic system. The proposed nuclear waste repository at Yucca Mountain, Nevada, United States, differs in significant ways from potential repository sites being considered by other nations. Nonetheless, observations of hydrogeological and hydrogeochemical systems of Yucca Mountain and Yucca Mountain analogs present multiple independent lines of evidence that can be used in evaluating long-term predictions of the evolution of hydrogeological and hydrogeochemical systems at Yucca Mountain. (authors)

Application of the iron-enriched basalt waste form for immobilizing commercial transuranic waste

International Nuclear Information System (INIS)

Owen, D.E.

1981-08-01

The principal sources of commercial transuranic (TRU) waste in the United States are identified. The physical and chemical nature of the wastes from these sources are discussed. The fabrication technique and properties of iron-enriched basalt, a rock-like waste form developed for immobilizing defense TRU wastes, are discussed. The application of iron-enriched basalt to commercial TRU wastes is discussed. Review of commercial TRU wastes from mixed-oxide fuel fabrication, light water reactor fuel reprocessing, and miscellaneous medical, research, and industrial sources, indicates that iron-enriched basalt is suitable for most types of commercial TRU wastes. Noncombustible TRU wastes are dissolved in the high temperature, oxidizing iron-enriched basalt melt. Combustible TRU wastes are immobilized in iron-enriched basalt by incinerating the wastes and adding the TRU-bearing ash to the melt. Casting and controlled cooling of the melt produces a devitrified, rock-like iron-enriched basalt monolith. Recommendations are given for testing the applicability of iron-enriched basalt to commercial TRU wastes

Mine waste disposal and managements

Energy Technology Data Exchange (ETDEWEB)

Cheong, Young Wook; Min, Jeong Sik; Kwon, Kwang Soo; Kim, Ok Hwan; Kim, In Kee; Song, Won Kyong; Lee, Hyun Joo [Korea Institute of Geology Mining and Materials, Taejon (Korea)

1998-12-01

Acid Rock Drainage (ARD) is the product formed by the atmospheric oxidation of the relatively common pyrite and pyrrhotite. Waste rock dumps and tailings containing sulfide mineral have been reported at toxic materials producing ARD. Mining in sulphide bearing rock is one of activity which may lead to generation and release of ARD. ARD has had some major detrimental affects on mining areas. The purpose of this study was carried out to develop disposal method for preventing contamination of water and soil environment by waste rocks dump and tailings, which could discharge the acid drainage with high level of metals. Scope of this study was as following: environmental impacts by mine wastes, geochemical characteristics such as metal speciation, acid potential and paste pH of mine wastes, interpretation of occurrence of ARD underneath tailings impoundment, analysis of slope stability of tailings dam etc. The following procedures were used as part of ARD evaluation and prediction to determine the nature and quantities of soluble constituents that may be washed from mine wastes under natural precipitation: analysis of water and mine wastes, Acid-Base accounting, sequential extraction technique and measurement of lime requirement etc. In addition, computer modelling was applied for interpretation of slope stability od tailings dam. (author). 44 refs., 33 tabs., 86 figs.

Increasing shaft depth with rock hoisting to the surface. [USSR

Energy Technology Data Exchange (ETDEWEB)

Durov, E.M.

1982-06-01

Schemes of shaft construction with increasing shaft depth depend on: shaft depth, shaft diameter, types of hoisting systems, schemes of shaft reinforcement. Investigations carried out in underground coal mines in the USSR show that waste rock haulage to the surface by an independent hoisting system is most economical. Installation of this system depends on the existing hoisting scheme. When one of the operating cages or skips can be removed without a negative influence on mine operation the system of rock waste hoisting is used. The hoisting bucket used for rock removal from the shaft bottom moves in the shaft section from which one of the cages or skips has been removed. Examples of using this scheme in Donbass, Kuzbass and other coal basins are given. Economic aspects of waste material hoisting to the surface are analyzed. The system is economical when the remaining hoisting system can accept additional loads after removal of a cage or skip from the shaft. Investigations show that use of a bucket with a capacity from 2.5 to 3.0 m/sup 3/ for waste rock removal from the shaft being modernized and deepened is most economical.

Alteration of national glass in radioactive waste repository host rocks: A conceptional review

International Nuclear Information System (INIS)

Apps, J.A.

1987-01-01

The storage of high-level radioactive wastes in host rocks containing natural glass has potential chemical advantages, especially if the initial waste temperatures are as high as 250 0 C. However, it is not certain how natural glasses will decompose when exposed to an aqueous phase in a repository environment. The hydration and devitrification of both rhyolitic and natural basaltic natural glasses are reviewed in the context of hypothetical thermodynamic phase relations, infrared spectroscopic data and laboratory studies of synthetic glasses exposed to steam. The findings are compared with field observations and laboratory studies of hydrating and devitrifying natural glasses. The peculiarities of the dependence of hydration and devitrification behavior on compositional variation is noted. There is substantial circumstantial evidence to support the belief that rhyolitic glasses differ from basaltic glasses in their thermodynamic stability and their lattice structure, and that this is manifested by a tendency of the former to hydrate rather than devitrify when exposed to water. Further research remains to be done to confirm the differences in glass structure, and to determine both physically and chemically dependent properties of natural glasses as a function of composition

Solid as a rock

International Nuclear Information System (INIS)

Pincus, H.J.

1984-01-01

Recent technologic developments have required a more comprehensive approach to the behavior of rock mass or rock substance plus discontinuities than was adequate previously. This work considers the inherent problems in such operations as the storage of hot or cold fluids in caverns and aquifers, underground storage of nuclear waste, underground recovery of heat from hydrocarbon fuels, tertiary recovery of oil by thermal methods, rapid excavation of large openings at shallow to great depths and in hostile environments, and retrofitting of large structures built on or in rock. The standardization of methods for determining rock properties is essential to all of the activities described, for use not only in design and construction but also in site selection and post-construction monitoring. Development of such standards is seen as a multidisciplinary effort

Research into basic rocks types

International Nuclear Information System (INIS)

1993-06-01

Teollisuuden Voima Oy (TVO) has carried out research into basic rock types in Finland. The research programme has been implemented in parallel with the preliminary site investigations for radioactive waste disposal in 1991-1993. The program contained two main objectives: firstly, to study the properties of the basic rock types and compare those with the other rock types under the investigation; secondly, to carry out an inventory of rock formations consisting of basic rock types and suitable in question for final disposal. A study of environmental factors important to know regarding the final disposal was made of formations identified. In total 159 formations exceeding the size of 4 km 2 were identified in the inventory. Of these formations 97 were intrusive igneous rock types and 62 originally extrusive volcanic rock types. Deposits consisting of ore minerals, industrial minerals or building stones related to these formations were studied. Environmental factors like natural resources, protected areas or potential for restrictions in land use were also studied

The Penokean orogeny in the Lake Superior region

Science.gov (United States)

Schulz, K.J.; Cannon, W.F.

2007-01-01

The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine-Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of volcanogenic massive sulfide deposits formed in the extending back-arc rift within the arc. Synchronous extension and subsidence of the Superior craton resulted in a broad shallow sea characterized by volcanic grabens (Menominee Group in northern Michigan). The classic Lake Superior banded iron-formations, including those in the Marquette, Gogebic, Mesabi and Gunflint Iron Ranges, formed in that sea. The newly established subduction zone caused continued arc volcanism until about 1850 Ma when a fragment of Archean crust, now the basement of the Marshfield terrane, arrived at the subduction zone. The convergence of Archean blocks of the Superior and Marshfield cratons resulted in the major contractional phase of the Penokean orogeny. Rocks of the Pembine-Wausau arc were thrust northward onto the Superior craton causing subsidence of a foreland basin in which sedimentation began at about 1850 Ma in the south (Baraga Group rocks) and 1835 Ma in the north (Rove and Virginia Formations). A thick succession of arc-derived turbidites constitutes most of the foreland basin-fill along with lesser volcanic rocks. In the southern fold and thrust belt tectonic thickening resulted in high-grade metamorphism of the sediments by 1830 Ma. At this same time, a suite of post-tectonic plutons intruded the deformed sedimentary sequence and accreted arc terranes marking the end of the Penokean orogeny. The Penokean orogen was strongly overprinted by younger tectonic and thermal events, some of which were previously ascribed to the Penokean. Principal among these was a

Rock stress measurements in the Grimsel Underground Rock Laboratory and their geological interpretation

International Nuclear Information System (INIS)

Braeuer, V.; Heusermann, S.; Pahl, A.

1989-01-01

Rock stress is being studied as part of the Swiss-German cooperation between the National Cooperative for the Storage of Radioactive Waste (NAGRA), the Research Centre for Environmental Sciences (GSF), and the Federal Institute for Geosciences and Natural Resources (BGR) in the Grimsel Rock Laboratory in Switzerland. Several methods and various equipment for measuring rock stress have been developed and tested in an approximately 200-m borehole drilled from a gallery at a depth of 450 m. The measurements were made continually during overcoring; the data were recorded and processed in a computer located downhole or outside the borehole. The results of the overcoring tests and of frac tests indicate a principle horizontal stress of 25-40 MPa, directed mainly NW-SE. Detailed geological mapping shows relationships between stress and rock structure. A zone of nearly unfractured rock exhibits an increase in stress and a change in stress direction. (orig.)

A new and superior ultrafine cementitious grout

International Nuclear Information System (INIS)

Ahrens, E.H.

1997-01-01

Sealing fractures in nuclear waste repositories concerns all programs investigating deep burial as a means of disposal. Because the most likely mechanism for contaminant migration is by dissolution and movement through groundwater, sealing programs are seeking low-viscosity sealants that are chemically, mineralogically, and physically compatible with the host rock. This paper presents the results of collaborative work directed by Sandia National Laboratories (SNL) and supported by Whiteshell Laboratories, operated by Atomic Energy of Canada, Ltd. The work was undertaken in support of the Waste Isolation Pilot Plant (WIPP), an underground nuclear waste repository located in a salt formation east of Carlsbad, NM. This effort addresses the technology associated with long-term isolation of nuclear waste in a natural salt medium. The work presented is part of the WIPP plugging and sealing program, specifically the development and optimization of an ultrafine cementitious grout that can be injected to lower excessive, strain-induced hydraulic conductivity in the fractured rock termed the Disturbed Rock Zone (DRZ) surrounding underground excavations. Innovative equipment and procedures employed in the laboratory produced a usable cement-based grout; 90% of the particles were smaller than 8 microns and the average particle size was 4 microns. The process involved simultaneous wet pulverization and mixing. The grout was used for a successful in situ test underground at the WIPP. Injection of grout sealed microfractures as small as 6 microns (and in one rare instance, 3 microns) and lowered the gas transmissivity of the DRZ by up to three orders of magnitude. Following the WIPP test, additional work produced an improved version of the grout containing particles 90% smaller than 5 microns and averaging 2 microns. This grout will be produced in dry form, ready for the mixer

Super analog computer for evaluating the safety of buried radioactive waste

International Nuclear Information System (INIS)

Cohen, B.L.

1980-01-01

It is argued that the past use of digital computer programs for evaluating the safety of buried radioactive waste has been largely wasteful and dangerously delusive. It is suggested to use actual rocks as the analog of buried waste. The problem of comparable rates of leaching of radioactive waste and of natural rock is discussed. Two examples are given of the use of natural rock as an ''analog computer'': one for high-level radioactive waste, and one for low-level radioactive waste. Digital computers have not contributed anything to two crucial questions: Can shafts be securely sealed. Does the heat crack the rock or have important effects on its chemistry. 4 refs

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

International Nuclear Information System (INIS)

Yoshida, H.; Metcalfe, R.; Yamamoto, K.; Murakami, Y.; Hoshii, D.; Kanekiyo, A.; Naganuma, T.; Hayashi, T.

2008-01-01

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure

Redox front formation in an uplifting sedimentary rock sequence: An analogue for redox-controlling processes in the geosphere around deep geological repositories for radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Yoshida, H. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan)], E-mail: dora@num.nagoya-u.ac.jp; Metcalfe, R. [Quintessa Japan, Queen' s Tower A7-707, Minatomirai, Yokohama 220-6007 (Japan); Yamamoto, K. [Nagoya University Museum, Material Research Section, Furocho, Nagoya 464-8602 (Japan); Murakami, Y. [Japan Atomic Energy Agency (JAEA), Tono Geoscience Centre (Japan); Hoshii, D.; Kanekiyo, A.; Naganuma, T. [Hiroshima University, Higashi Hiroshima, Kagamiyama 1-4-4 (Japan); Hayashi, T. [Asahi University, Department of Dental Pharmacology, Hozumi, Gifu (Japan)

2008-08-15

Subsurface redox fronts control the mobilization and fixation of many trace elements, including potential pollutants such as certain radionuclides. Any safety assessment for a deep geological repository for radioactive wastes needs to take into account adequately the long-term redox processes in the geosphere surrounding the repository. To build confidence in understanding these processes, a redox front in a reduced siliceous sedimentary rock distributed in an uplifting area in Japan has been studied in detail. Geochemical analyses show increased concentrations of Fe and trace elements, including rare earth elements (REEs), at the redox front, even though concentrations of reduced rock matrix constituents show little change. Detailed SEM observations revealed that fossilized microorganisms composed of amorphous granules made exclusively of Fe and Si occur in the rock's pore space. Microbial 16S rDNA analysis suggests that there is presently a zonation of different bacterial groups within the redox band, and bacterial zonation played an important role in the concentration of Fe-oxyhydroxides at the redox front. These water-rock-microbe interactions can be considered analogous to the processes occurring in the redox fronts that would develop around geological repositories for radioactive waste. Once formed, the Fe-oxyhydroxides within such a front would be preserved even after reducing conditions resume following repository closure.

A heat source probe for measuring thermal conductivity in waste rock dumps

International Nuclear Information System (INIS)

Blackford, M.G.; Harries, J.R.

1985-10-01

The development and use of a heat source probe to measure the thermal conductivity of the material in a waste rock dump is described. The probe releases heat at a constant rate into the surrounding material and the resulting temperature rise is inversely related to the thermal conductivity. The probe was designed for use in holes in the dump which are lined with 50 mm i.d. polyethylene liners. The poor thermal contact between the probe and the liner and the unknown conductivity of the backfill material around the liner necessitated long heating and cooling times (>10 hours) to ensure that the thermal conductivity of the dump material was being measured. Temperature data acquired in the field were analysed by comparing them with temperatures calculated using a two-dimensional cylindrical model of the probe and surrounding material, and the heat transfer code HEATRAN

Characterization of steel grit recovered from ornamental rocks waste by magnetic separation

International Nuclear Information System (INIS)

Junca, E.; Telles, V.B.; Rodrigues, G.F.; Oliveira, J.R. de; Tenorio, J.A.S.

2010-01-01

The aim of this work is characterization of steel grit recovered from ornamental rock waste by magnetic separation. The magnetic separation was realized in three steps: first, using a high intensity wet magnetic separator, which used only the remaining magnetic field of equipment. In the second step, the magnetic material obtained in the first phase was subjected to a new manual magnetic separation using rare earth magnets. In a third step, magnetic material obtained with rare earth magnets was subjected to manual magnetic separation using ferrite magnets. After the magnetic separation, the material was sent to characterization which was obtained by chemical analysis, scanning electron microscopy, X-ray diffraction and size analysis. The size analysis showed that the concentrate range from 0,5 to 563,67 μm with 4 wt.% over 100 μm and content metallic iron of 93 wt%. (author)

THM-coupled modeling of selected processes in argillaceous rock relevant to rock mechanics; THM-Gekoppelte Modellierung ausgewaehlter gesteinsmechanisch relevanter Prozesse im Tongestein

Energy Technology Data Exchange (ETDEWEB)

Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) mbH, Braunschweig (Germany). Repository Safety Research Div.

2012-08-15

Scientific investigations in European countries other than Germany concentrate not only on granite formations (Switzerland, Sweden) but also on argillaceous rock formations (France, Switzerland, Belgium) to assess their suitability as host and barrier rock for the final storage of radioactive waste. In Germany, rock salt has been under thorough study as a host rock over the past few decades. According to a study by the German Federal Institute for Geosciences and Natural Resources, however, not only salt deposits but also argillaceous rock deposits are available at relevant depths and of extensions in space which make final storage of high-level radioactive waste basically possible in Germany. Equally qualified findings about the suitability/unsuitability of non-saline rock formations require fundamental studies to be conducted nationally because of the comparatively low level of knowledge. The article presents basic analyses of coupled mechanical and hydraulic properties of argillaceous rock formations as host rock for a repository. The interaction of various processes is explained on the basis of knowledge derived from laboratory studies, and open problems are deduced. For modeling coupled processes, a simplified analytical computation method is proposed and compared with the results of numerical simulations, and the limits to its application are outlined. (orig.)

Test procedures for salt rock

International Nuclear Information System (INIS)

Dusseault, M.B.

1985-01-01

Potash mining, salt mining, design of solution caverns in salt rocks, disposal of waste in salt repositories, and the use of granular halite backfill in underground salt rock mines are all mining activities which are practised or contemplated for the near future. Whatever the purpose, the need for high quality design parameters is evident. The authors have been testing salt rocks in the laboratory in a number of configurations for some time. Great care has been given to the quality of sample preparation and test methodology. This paper describes the methods, presents the elements of equipment design, and shows some typical results

Evaluation of salt and mine rock disposal. Project No. 76-283

International Nuclear Information System (INIS)

1976-11-01

Studies are being performed on the isolation of nuclear waste in geological formations; this would entail constructing an underground mine in selected rock strata for waste storage. Rocks removed from the mine during construction must be either disposed of permanently or temporarily stored for later backfill into the mine. Several methods of storing or disposing of the mined rock are discussed in this report. The technical feasibility, cost, advantages and disadvantages of each method are presented and the ranking of methods based on currently available data is discussed. Salt, shale, granite, and limestone are covered

10 CFR 960.3-1-2 - Diversity of rock types.

Science.gov (United States)

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false Diversity of rock types. 960.3-1-2 Section 960.3-1-2... NUCLEAR WASTE REPOSITORY Implementation Guidelines § 960.3-1-2 Diversity of rock types. Consideration... sites for characterization shall have different types of host rock. ...

Nagra technical report 14-02, Geological basics - Dossier VI - Barrier properties of proposed host rock sediments and neighbouring rock

International Nuclear Information System (INIS)

Gautschi, A.; Deplazes, G.; Traber, D.; Marschall, P.; Mazurek, M.; Gimmi, T.; Maeder, U.

2014-01-01

This dossier is the sixth of a series of eight reports concerning the safety and technical aspects of locations for the disposal of radioactive wastes in Switzerland. It discusses the barrier properties of the proposed host rock sediments and neighbouring rock layers. The mineralogical composition of the host rocks are discussed as are their pore densities and hydrological properties. Diffusion aspects are discussed. The aquifer systems in the proposed depository areas and their classification are looked at. The barrier properties of the host rocks and those of neighbouring sediments are discussed. Finally, modelling concepts and parameters for the transport of radionuclides in the rocks are discussed

Creation and Plan of an Underground Geologic Radioactive Waste Isolation Facility at the Nizhnekansky Rock Massif in Russia

International Nuclear Information System (INIS)

Gupalo, T A; Kudinov, K G; Jardine, L J; Williams, J

2004-01-01

This joint geologic repository project in Russia was initiated in May 2002 between the United States (U.S.) International Science and Technology Center (ISTC) and the Federal State Unitary Enterprise ''All-Russian Research and Design Institute of Production Engineering'' (VNIPIPT). The project (ISTC Partner Project 2377) is funded by the U.S. Department of Energy Office of Civilian Radioactive Waste Management (DOE-RW) for a period of 2-1/2 years. ISTC project activities were integrated into other ongoing geologic repository site characterization activities near the Mining and Chemical Combine (MCC K-26) site. This allowed the more rapid development of a plan for an underground research laboratory, including underground design and layouts. It will not be possible to make a final choice between the extensively studied Verkhne-Itatski site or the Yeniseiski site for construction of the underground laboratory during the project time frame because additional data are needed. Several new sources of data will become available in the next few years to help select a final site. Studies will be conducted at the 1-km deep borehole at the Yeniseisky site where drilling started in 2004. And in 2007, after the scheduled shutdown of the last operating reactor at the MCC K-26 site, data will be collected from the rock massif as the gneiss rock cools, and the cool-down responses modeled. After the underground laboratory is constructed, the data collected and analyzed, this will provide the definitive evidence regarding the safety of the proposed geologic isolation facilities for radioactive wastes (RW). This data will be especially valuable because they will be collected at the same site where the wastes will be subsequently placed, rather than on hypothetical input data only. Including the operating costs for 10 to 15 years after construction, the cost estimate for the laboratory is $50M. With additional funding from non-ISTC sources, it will be possible to complete this

Evidence for the incorporation of lead into barite from waste rock pile materials

Energy Technology Data Exchange (ETDEWEB)

COURTIN-NOMADE, ALEXANDRA; SOUBRAND-COLIN, MARILYNE; MARCUS, MATTHEW A.; FAKRA, SIRINE .C

2008-01-21

Because Pb is one of the most toxic elements and is found as a major contaminant in mining environments, this study aims to identify the distribution of this element in host phases issued from the alteration of mine wastes. The sampling location was a former mine near Oakland, California (USA). This mine was once a source of sulfide minerals from which sulfuric acid was made. The material discussed in this paper was collected in iron hardpans that were formed within the waste rock pile resulting from the excavation work. In most contaminated environments (soils, mine waste), secondary metal-bearing phases arising from alteration processes are usually fine-grained (from 10 {micro}m to less than 1 {micro}m) and highly heterogeneous, requiring the use of micron-scale techniques. We performed micro-Raman spectroscopy, microscanning X-ray diffraction (SXRD), and microextended X-ray near edge spectroscopy (XANES) to determine the relationships between Pb and a Ba/Fe-rich host phase. Micro-Raman spectroscopy suggests that Pb is preferentially incorporated into barite rather than goethite. Results from micro-Raman experiments show the high sensitivity of this analytical tool to the incorporation of Pb into barite by being especially sensitive to the variations of the S-O bond and showing the characteristic bands due to the contribution of Pb. This association is confirmed and is well-illustrated by micro-SXRD mineral species maps showing the correlation between Pb and barite. Microfocused XANES indicates that Pb is present as Pb{sup 2+}, agreeing with the in situ physicochemical parameters.

Underground laboratories for rock mechanics before radioactive waste

International Nuclear Information System (INIS)

Duffaut, P.

1985-01-01

Many rock mechanics tests are performed in situ, most of them underground since 1936 at the Beni Bahdel dam. The chief tests for understanding the rock mass behaviour are deformability tests (plate test and pressure cavern test, including creep experiments) and strength tests (compression of a mine pillar, shear test on rock mass or joint). Influence of moisture, heat, cold and freeze are other fields of investigation which deserve underground laboratories. Behaviour of test galleries, either unsupported or with various kinds of support, often is studied along time, and along the work progression, tunnel face advance, enlargement or deepening of the cross section. The examples given here help to clarify the concept of underground laboratory in spite of its many different objectives. 38 refs.; 1 figure; 1 table

Radionuclide fixation mechanisms in rocks

International Nuclear Information System (INIS)

Nakashima, S.

1991-01-01

In the safety evaluation of the radioactive waste disposal in geological environment, the mass balance equation for radionuclide migration is given. The sorption of radionuclides by geological formations is conventionally represented by the retardation of the radionuclides as compared with water movement. In order to quantify the sorption of radionuclides by rocks and sediments, the distribution ratio is used. In order to study quantitatively the long term behavior of waste radionuclides in geological environment, besides the distribution ratio concept in short term, slower radionuclide retention reaction involving mineral transformation should be considered. The development of microspectroscopic method for long term reaction path modeling, the behavior of iron during granite and water interaction, the reduction precipitation of radionuclides, radionuclide migration pathways, and the representative scheme of radionuclide migration and fixation in rocks are discussed. (K.I.)

Sulfide oxidation and the natural attenuation of arsenic and trace metals in the waste rocks of the abandoned Seobo tungsten mine, Korea

International Nuclear Information System (INIS)

Lee, Pyeong-koo; Kang, Min-Ju; Choi, Sang-Hoon; Touray, Jean-Claude

2005-01-01

Mineralogical examinations were performed to characterize the formation of secondary minerals and natural removal process of dissolved As and trace metals (Pb, Zn and Cu) from sulfide oxidation. Laboratory-based leaching tests were also conducted to determine whether the concentrations of As and trace metals in the leachates from waste-rock materials and contaminated soil could be affected by the presence acids such as acid rainwater or acid mine drainage. Waste-rock materials and contaminated soil were compared by 4-day leaching tests using HNO 3 solutions of increasing acidity (0.00001-0.1mole/L). Mineralogical studies of the waste rocks confirmed the presence of Fe-(oxy)hydroxides (e.g. goethite), jarosite, elemental S, Fe-sulfates, amorphous Fe-As phases, anglesite and covellite as secondary minerals. These secondary minerals act as mineralogical scavengers of dissolved trace metals, SO 4 2- and acidity released by sulfide oxidation. Arsenic was attenuated by the adsorption on Fe-(oxy)hydroxides and/or the formation of an amorphous Fe-As phase, with a Fe/As ratio=1 (maybe scorodite: FeAsO 4 .2H 2 O). Electron probe microanalyses data showed that the Fe-(oxy)hydroxides had high concentrations of Pb (up to 21wt%), with appreciable amounts of As (up to 7.7wt%), Zn (up to 4.6wt%) and Cu (up to 2.5wt%) indicating that dissolved metals were co-precipitated and adsorbed onto Fe-(oxy)hydroxides, Fe(Mn)-hydroxides and Fe-sulfates. The results of the leaching experiments within the pH-range 3.5-5.0 indicated that acidic rainstorms may leach minor amounts of Pb (ca. 1.7-4.0% of total), Zn (ca. 0.8-2.2% of total), Cu (ca. 0.0-0.2% of total) and As (ca. 0.02-0.1% of total) from waste rocks, including the dissolution of soluble secondary minerals previously formed during prolonged dry periods, while dissolution of these elements was negligible from the contaminated soil. In the pH-range 1.0-3.0, the leaching of Pb (ca. 2.4-31% of total) and As (ca. 0.1-5.8% of total) from

Measurements and modeling of gas fluxes in unsaturated mine waste materials

Energy Technology Data Exchange (ETDEWEB)

Kabwe, L.K.

2008-07-01

A technique known as dynamic closed chamber (DDC) was recently developed to measure carbon dioxide (CO{sub 2}) fluxes from the soil surface to the atmosphere. The field application of the DCC was investigated in this thesis with a particular focus on quantifying reaction rates in 2 waste-rock piles at the Key Lake uranium mine in northern Saskatchewan. The dominant geochemical reactions in both waste-rock piles were not typical of acid rock drainage (ARD) waste-rock piles. The CO{sub 2} fluxes measured in this study occur in the organic material underlying the waste rocks. The study provided a complete suite of measurements needed to characterize spatial distribution of CO{sub 2} fluxes on larger-scale studies of waste-rock piles. In comparison to other CO{sub 2} flux measuring techniques, the DCC method accurately quantified field soil respiration and had an added advantage in terms of speed and repeatability. The DCC was also used to investigate CO{sub 2} fluxes under the climatic variables that affect soil water content in waste-rock piles. A simple model for predicting the effects of soil water content on CO{sub 2} diffusion coefficient and concentration profiles was developed and verified. It was concluded that the DCC method is suitable for field applications to quantify CO{sub 2} fluxes and to characterize the spatial and temporal dynamics of CO{sub 2} fluxes from unsaturated C-horizon soils and waste-rock piles.

Mechanisms of hydrothermal alteration in a granitic rock. Consequences for high-level radioactive waste disposal

International Nuclear Information System (INIS)

Parneix, J.C.

1987-06-01

The study of hydrothermal alteration in the Auriat granitic rock (France, Massif-Central) has evidenced three main events: - a pervasive chloritisation of biotites in some parts of the drill-core, - an alteration localized around subvertical cracks and superimposed on previously chloritized or unaltered granite, - an alteration localized around subhorizontal cracks cross-cutting the preceding ones. The second type of alteration, produced by a geothermal system, gives the most interesting results to be applied to the nuclear radwaste disposal problem. Among primary minerals of granite, only biotite (or chlorite) and oligoclase are intensively altered. Therefore, the chemical composition of these minerals induces the nature of secondary parageneses. These, associated to the subvertical cracks network, indicate a thermal gradient of 150 C/Km. The geochemical code has allowed to corroborate that the thermal gradient was responsible for the occurrence of different parageneses with depth. Moreover, it was shown that the variable mineralogy around cracks was due to a thermal profile established at equilibrium between the rock and the fluid. Therefore, the extent of the alteration was proportional to the thermal power of the fluid. A dissolution and next a precipitation phase of new minerals characterize hydrothermal alteration, which is due to the thermal power emitted by radioactive waste and linked with the evolution of temperature during time. This alteration provokes two favourable events to storage: decrease of rock porosity and increase of sorption capacity [fr

Rock engineering applications, 1991

International Nuclear Information System (INIS)

Franklin, J.A.; Dusseault, M.B.

1991-01-01

This book demonstrates how to apply the theories and principles of rock engineering to actual engineering and construction tasks. It features insights on geology for mining and tunnelling applications. It is practical resource that focuses on the latest technological innovation and examines up-to-date procedures used by engineers for coping with complex rock conditions. The authors also discuss question related to underground space, from design approaches to underground housing and storage. And they cover the monitoring of storage caverns for liquid and gaseous products or toxic and radioactive wastes

Shaft sealing concepts for high-level radioactive waste repositories based on the host-rock options rock salt and clay stone; Schachtverschlusskonzepte fuer zukuenftige Endlager fuer hochradioaktive Abfaelle fuer die Wirtsgesteinsoptionen Steinsalz und Ton

Energy Technology Data Exchange (ETDEWEB)

Kudla, Wolfram; Gruner, Matthias [TU Bergakademie Freiberg (Germany). Inst. fuer Erdbau und Spezialtiefbau; Herold, Philipp; Jobmann, Michael [DBE Technology GmbH, Peine (Germany)

2015-07-01

Unlike the shaft barriers used for the dry preservation of former mine workings and underground storage sites, shaft seals designed for radioactive-waste repositories must also fulfil additional requirements associated with the design diversity of the sealing system. This diversity makes use of the simple redundancy principle in order to prevent the proliferation of defects. In practice this means combining several sealing elements made from different materials or from materials with different properties. The R and D project, Shaft sealing systems for final repositories for high-level radioactive waste (ELSA) - phase 2: concept design for shaft seals and testing of the functional elements of shaft seals', which was funded by the Federal Ministry for Economic Affairs and Energy (BMWi), set out to investigate potential sealing elements for the two host-rock options rock salt and mudstone. This paper combines the text that the authors presented at the First International Freiberg Shaft Colloquium held at the Freiberg University of Mining and Technology on 01.10.2014 with a presentation on the sealing elements that were investigated as part of the R and D project.

Diffusion in the matrix of granitic rock

International Nuclear Information System (INIS)

Birgersson, L.; Neretnieks, I.

1982-07-01

A migration experiment in the rock matrix is presented. The experiment has been carried out in undisturbed rock, that is rock under its natural stress environment. Since the experiment was performed at the 360 m-level (in the Stripa mine), the rock had nearly the same conditions as the rock surrounding a nuclear waste storage. The results show that all three tracers (Uranine, Cr-EDTA and I - ) have passed the disturbed zone from the injection hole and migrated into undisturbed rock. At the distance of 11 cm from the injection hole 5-10 percent of the injection concentration was found. The results also indicate that the tracer have passed through fissure filling material. These results indicate that it is possible for tracers (and therefore radionuclides) to migrate from a fissure, through fissure filling material, and into the undisturbed rock matrix. (Authors)

Rapid formation of rock armour for soil - rock fragment mixture during simulated rainfall

Science.gov (United States)

Poultney, E.; McGrath, G. S.; Hinz, C.

2009-04-01

Preventing erosion is an important issue in disturbed semi-arid and arid landscapes. This is in particular of highest importance for mining companies while undertaking land rehabilitation. An onsite investigation of the impact of surface rock fragments on erosion was conducted at Telfer goldmine in the Great Sandy Desert, Western Australia. The study site is a waste rock dump designed to mimic the concave slope of a natural mesa to both discourage erosion and blend in with its natural surroundings. Four treatments were used to construct the slope: two are topsoil mixed with rock fragments, and two are unmixed topsoil. A field study investigating erosion rills, particle size distribution, rock fragment coverage surface roughness and vegetation was carried out to determine changes down and across slope. The treatments constructed by mixing topsoil and rock fragments are more stable and show rock fragment distributions that more closely resemble patterns found on natural mesas surrounding Telfer. A controlled study using trays of topsoil mixed with rock fragment volumes of 50%, 60%, 70% and 80% were used to investigate how varying mixtures of rock fragments and topsoil erode using rainfall intensities between 20 and 100 mm h-1. Two runs of 25 minutes each were used to assess the temporal evolution of rock armouring. Surface coverage results converged for the 50%, 60% and 70% mixtures after the first run to coverage of about 90%, suggesting that fine sediment proportion does not affect rate and degree of rock armouring.

Fine-grained sheet silicate rocks

International Nuclear Information System (INIS)

Weaver, C.E.

1977-09-01

Considerable interest has been shown in the possibility of using shales as repositories for radioactive waste and a variety of other waste products, and it appears that over the next few years much money and effort will be expended to investigate and test a wide variety of shales. If shales are to be studied in detail by a large number of investigators, it is important that all concerned have the same concept of what constitutes a shale. The term shale and other terms for fine-grained rocks have been used for many years and have been continually redefined. Most definitions predate the development of modern instrumentation and are based on field observations and intuition; however, the main problem is the diversity of definitions. An attempt is made here to develop a simple, rational classification of fine-grained sediments, and it is hoped that this classification will eliminate some of the present ambiguity. In order that the classification be pertinent, mineral composition and textural data were compiled and evaluated. The data on unconsolidated and consolidated sediments were contrasted and the effects of burial diagenesis assessed. It was found necessary to introduce a new term, physil, to describe all sheet silicate minerals. In contrast to the term clay mineral, the term physil has no size connotation. A simple classification is proposed that is based on the percentage of physils and grain size. In Part II the fine-grained physil rocks are classified on the basis of physil type, non-physil minerals, and texture. Formations are listed which have the mineral and textural characteristics of the most important rock types volumetrically. Selected rock types, and the formations in which they can be found, are recommended for laboratory study to determine their suitability for the storage of high-level radioactive waste

Comparison of the intermediate storage periods and areas required for final storage of high-level radioactive waste and spent fuel in various types of host rock

International Nuclear Information System (INIS)

Mueller-Hoeppe, N.; Lerch, C.; Jobmann, M.; Filbert, W.

2005-01-01

The present new version of the German concept for radioactive waste and spent fuel management is based on the assumption that a repository for high-level waste and spent fuel will not be required until 2030. One reason frequently given for this date is the intermediate storage period of at least forty years to allow the very high initial heat generation to decay. However, calculations performed by the authors have shown that the minimum intermediate storage period for a repository in rock salt is only between four and nineteen years, depending on the final storage concept and the load of the waste package. In clay as a host rock, the minimum intermediate storage times were calculated to be between 31 and 142 years; the same time spans are expected to apply to final storage in magmatic rock, such as granite. The maximum permissible loads of a container holding spent fuel in salt are many times those in clay and granite, respectively. It was also seen that the area requirement for final storage of the same waste structures is roughly a factor of ten higher in clay than in salt. The differences between granite and salt are similar. The reasons for these grave differences, on the one hand, are the better thermal conductivity of salt and, on the other hand, the better heat tolerance of the crushed salt used as backfill material compared to that of bentonite used in the clay and granite concepts. While salt will allow temperatures of up to 200 C, the maximum temperature in bentonite is limited to 100 C. (orig.)

National waste terminal storage program. Progress report, September 1977

International Nuclear Information System (INIS)

Asher, J.M.

1977-01-01

Project reports are given of the following studies: USGS Water Resources Division study of Louisiana salt domes; Northeast Texas Salt Dome Basin study; salt-dome hydrology in Mississippi; volcanic rocks; crystalline rocks; Paradox Basin; geologic studies at the Nevada Test Site; heat transfer/thermal analysis; waste/rock interaction; rock mechanics; borehole plugging; safety and reliability; shale and clay mineral studies; conceptual design of NWTS repositories; waste container studies; transportation/logistics study; and environmental study

Waste package designs for disposal of high-level waste in salt formations

International Nuclear Information System (INIS)

Basham, S.J. Jr.; Carr, J.A.

1984-01-01

In the United States of America the selected method for disposal of radioactive waste is mined repositories located in suitable geohydrological settings. Currently four types of host rocks are under consideration: tuff, basalt, crystalline rock and salt. Development of waste package designs for incorporation in mined salt repositories is discussed. The three pertinent high-level waste forms are: spent fuel, as disassembled and close-packed fuel pins in a mild steel canister; commercial high-level waste (CHLW), as borosilicate glass in stainless-steel canisters; defence high-level waste (DHLW), as borosilicate glass in stainless-steel canisters. The canisters are production and handling items only. They have no planned long-term isolation function. Each waste form requires a different approach in package design. However, the general geometry and the materials of the three designs are identical. The selected waste package design is an overpack of low carbon steel with a welded closure. This container surrounds the waste forms. Studies to better define brine quantity and composition, radiation effects on the salt and brines, long-term corrosion behaviour of the low carbon steel, and the leaching behaviour of the spent fuel and borosilicate glass waste forms are continuing. (author)

Development of soda-lime glasses from ornamental rock wastes

International Nuclear Information System (INIS)

Babisk, Michelle Pereira

2009-01-01

During the ornamental rocks production, among other steps, one saw the rock blocks in order to transform them into semi-finished plates. In this step, expressive amounts of residues are generated, which are not properly discharged in nature, without any programmed utilization. The residues of silicide rocks present, in their compositions, oxides which are raw materials employed to fabricate soda-lime type glasses (containing SiO_2, Al_2O_3, CaO, Na_2O and K_2O). On the other hand the residues of carbonatic rocks are constituted of glass net modifier oxides, like CaO and MgO. In this work it was developed four types of soda-lime glasses using ornamental rock residues, where the glasses compositions were adjusted by adding sand, as silica source, as well as sodium and calcium carbonates as sources of Na_2O and CaO, respectively. The obtained glasses were characterized by means of Archimed's method for densities measurements, microstructure by using optical and electronic microscopy, phases by means of X-ray diffraction (XRD), hardness by Vickers indentation, spectroscopy (UV/VIS), and hydrolytic resistance according to ISO 719. The XRD analyses confirmed the compositions total vitrification, where the greened aspect of the samples was due to the presence of the iron oxides. The produced glasses properties were compared with those of commercial glasses aiming their industrial employment. The main difference between the produced glasses and those commercials varied primarily regarding the amount of carbonates incorporated. The results showed that the ornamental rocks residues may be used as raw materials for glasses fabrication, and they found a useful economic destination rather than discharge which promotes undesirable environmental impact. (author)

Coupled heat and groundwater flow in porous rock

International Nuclear Information System (INIS)

Rae, J.; Robinson, P.C.; Wickens, L.M.

1983-01-01

There are a number of technical areas where coupled heat and flow problems occur for water in porous rock. The area of most interest to the authors has been the possible disposal underground of high-level radioactive waste. High-level waste can emit enough heat to drive significant flows by buoyancy effects and groundwater flow is expected to be the chief transport process for solute leached from such a repository. The possible disposal of radioactive waste under the seabed raises many similar questions and needs similar techniques to find answers. Other areas where related questions arise are the storage and retrieval of hot water in underground reservoirs, the attempts to extract useful geothermal energy by pumping water into fracture systems in hot rock and in certain thermal techniques for persuading oil to flow in tight reservoirs. The authors address questions in a rather general way and give examples which lie more in the area of waste disposal

GRS' research on clay rock in the Mont Terri underground laboratory

Energy Technology Data Exchange (ETDEWEB)

Wieczorek, Klaus; Czaikowski, Oliver [Gesellschaft fuer Anlagen- und Reaktorsicherheit gGmbH, Braunschweig (Germany)

2016-07-15

For constructing a nuclear waste repository and for ensuring the safety requirements are met over very long time periods, thorough knowledge about the safety-relevant processes occurring in the coupled system of waste containers, engineered barriers, and the host rock is indispensable. For respectively targeted research work, the Mont Terri rock laboratory is a unique facility where repository research is performed in a clay rock environment. It is run by 16 international partners, and a great variety of questions are investigated. Some of the work which GRS as one of the Mont Terri partners is involved in is presented in this article. The focus is on thermal, hydraulic and mechanical behaviour of host rock and/or engineered barriers.

MCDIRC: A model to estimate creep produced by microcracking around a shaft in intact rock

International Nuclear Information System (INIS)

Wilkins, B.J.S.; Rigby, G.L.

1989-12-01

Atomic Energy of Canada Limited (AECL) is studying the concept of disposing of nuclear fuel waste in a vault in plutonic rock. Models are being developed to predict the mechanical behaviour of the rock in response to excavation and heat from the waste. The dominant mechanism of deformation at temperatures below 150 degrees C is microcracking, which results in rock creep and a decrease in rock strength. A model has been constructed to consider the perturbation of the stress state of intact rock by a vertical cylindrical opening. Slow crack-growth data are used to estimate time-dependent changes in rock strength, from which the movement (creep) of the opening wall and radial strain in the rock mass can be estimated

Reference stratigraphy and rock properties for the Waste Isolation Pilot Plant (WIPP) project

International Nuclear Information System (INIS)

Krieg, R.D.

1984-01-01

A stratigraphic description of the country rock near the working horizon at the Waste Isolation Pilot Plant (WIPP) is presented along with a set of mechanical and thermal properties of materials involved. Data from 41 cores and shafts are examined. The entire stratigraphic section is found to vary in elevation in a regular manner, but individual layer thicknesses and relative separation between layers are found to have no statistically significant variation over the one mile north to south extent of the working horizon. The stratigraphic description is taken to be relative to the local elevation of Anhydrite b. The material properties have been updated slightly from those in the July 1981 Reference Stratigraphy. This reference stratigraphy/properties document is intended primarily for use in thermal/structural analyses. This document supercedes the July 1981 stratigraphy/properties document. 31 references, 7 figures

Physical and mechanical properties of degraded waste surrogate material

International Nuclear Information System (INIS)

Hansen, F.D.; Mellegard, K.D.

1998-03-01

This paper discusses rock mechanics testing of surrogate materials to provide failure criteria for compacted, degraded nuclear waste. This daunting proposition was approached by first assembling all known parameters such as the initial waste inventory and rock mechanics response of the underground setting after the waste is stored. Conservative assumptions allowing for extensive degradation processes helped quantify the lowest possible strength conditions of the future state of the waste. In the larger conceptual setting, computations involve degraded waste behavior in transient pressure gradients as gas exits the waste horizon into a wellbore. Therefore, a defensible evaluation of tensile strength is paramount for successful analyses and intentionally provided maximal failed volumes. The very conservative approach assumes rampant degradation to define waste surrogate composition. Specimens prepared from derivative degradation product were consolidated into simple geometries for rock mechanics testing. Tensile strength thus derived helped convince a skeptical peer review panel that drilling into the Waste Isolation Pilot Plant (WIPP) would not likely expel appreciable solids via the drill string

Proceedings of the scientific visit on crystalline rock repository development.

Energy Technology Data Exchange (ETDEWEB)

Mariner, Paul E.; Hardin, Ernest L.; Miksova, Jitka [RAWRA, Czech Republic

2013-02-01

A scientific visit on Crystalline Rock Repository Development was held in the Czech Republic on September 24-27, 2012. The visit was hosted by the Czech Radioactive Waste Repository Authority (RAWRA), co-hosted by Sandia National Laboratories (SNL), and supported by the International Atomic Energy Agency (IAEA). The purpose of the visit was to promote technical information exchange between participants from countries engaged in the investigation and exploration of crystalline rock for the eventual construction of nuclear waste repositories. The visit was designed especially for participants of countries that have recently commenced (or recommenced) national repository programmes in crystalline host rock formations. Discussion topics included repository programme development, site screening and selection, site characterization, disposal concepts in crystalline host rock, regulatory frameworks, and safety assessment methodology. Interest was surveyed in establishing a %E2%80%9Cclub,%E2%80%9D the mission of which would be to identify and address the various technical challenges that confront the disposal of radioactive waste in crystalline rock environments. The idea of a second scientific visit to be held one year later in another host country received popular support. The visit concluded with a trip to the countryside south of Prague where participants were treated to a tour of the laboratory and underground facilities of the Josef Regional Underground Research Centre.

Site investigations, design, construction, operation, shutdown and surveillance of repositories for low- and intermediate-level radioactive wastes in rock cavities

International Nuclear Information System (INIS)

1984-01-01

The report provides an overview and technical guidelines for considerations and for activities to be undertaken for safety assessment, site investigations, design, construction, operation, shutdown and surveillance of repositories for the disposal of low- and intermediate-level radioactive wastes in rock cavities. A generalized sequence of investigations is introduced which proceeds through region and site selection to the stage where the site is confirmed by detailed geoscientific investigations as being suitable for a waste repository. The different procedures and somewhat specific investigative needs with respect to existing mines are dealt with separately. General design, as well as specific requirements with respect to the different stages of design and construction, are dealt with. A review of activities related to the operational and post-operational stages of repositories in rock cavities is presented. The report describes in general terms the procedures related to different stages of disposal operation; also the conditions for shutdown together with essential shutdown and sealing activities and the related safety assessment requirements. Guidance is also given on the surveillance programme which will allow for inspection, testing, maintenance and security of a disposal facility during the operational phase, as well as for the post-operational stage for periods determined as necessary by the national authorities

Accumulated energy determination in salts rocks irradiated by means of thermoluminescence techniques: application to the high level radioactive wastes repositories analysis

International Nuclear Information System (INIS)

Dies, J.; Ortega. J.; Tarrasa. F.; Cuevas, C.

1995-01-01

The report summarizes the study carried out to develop the radiation effects on salt rocks in order to repository the high level radioactive wastes. The study is structured into 3 main aspects: 1.- Analysis of irradiation experiences in Haw project of Pet ten reactor. 2.- Irradiation of salt sample of CESAR industrial irradiator. 3.- Correlation study between the accumulated energy, termoluminescence answer and the defect concentration

Expected environment for waste packages in a salt repository

International Nuclear Information System (INIS)

Pederson, L.R.; Clark, D.E.; Hodges, F.N.; McVay, G.L.; Rai, D.

1983-01-01

This paper discusses results of recent efforts to define the very near-field (within approximately 2 m) environmental conditions to which waste packages will be exposed in a salt repository. These conditions must be considered in the experimental design for waste package materials testing, which includes corrosion of barrier materials and leaching of waste forms. Site-specific brine compositions have been determined, and standard brine compositions have been selected for testing purposes. Actual brine compositions will vary depending on origin, temperature, irradiation history, and contact with irradiated rock salt. Results of irradiating rock salt, synthetic brines, rock salt/brine mixtures, and reactions of irradiated rock salt with brine solutions are reported. 38 references, 3 figures, 2 tables

Compressible fluid flow through rocks of variable permeability

International Nuclear Information System (INIS)

Lin, W.

1977-01-01

The effectiveness of course-grained igneous rocks as shelters for burying radioactive waste can be assessed by determining the rock permeabilities at their in situ pressures and stresses. Analytical and numerical methods were used to solve differential equations of one-dimensional fluid flow through rocks with permeabilities from 10 4 to 1 nD. In these calculations, upstream and downstream reservoir volumes of 5, 50, and 500 cm 3 were used. The optimal size combinations of the two reservoirs were determined for measurements of permeability, stress, strain, acoustic velocity, and electrical conductivity on low-porosity, coarse-grained igneous rocks

Clay club catalogue of characteristics of argillaceous rocks

International Nuclear Information System (INIS)

2005-01-01

The OECD/NEA Working Group on the Characterisation, the Understanding and the Performance of Argillaceous Rocks as Repository Host Formations, namely the Clay Club, examines the various argillaceous rocks that are being considered for the deep geological disposal of radioactive waste, i.e. from plastic, soft, poorly indurated clays to brittle, hard mud-stones or shales. The Clay Club considered it necessary and timely to provide a catalogue to gather in a structured way the key geo-scientific characteristics of the various argillaceous formations that are - or were - studied in NEA member countries with regard to radioactive waste disposal. The present catalogue represents the outcomes of this Clay Club initiative. (author)

Evaluation of possible host rocks for China's high level radioactive waste repository and the progress in site characterization at the Beishan potential site in NW China's Gansu province

International Nuclear Information System (INIS)

Wang Ju; Jin Yuanxin; Chen Zhangru; Chen Weiming; Wang Wenguang

2000-01-01

Evaluation of possible host rocks for China's high level radioactive waste repository is summarized in this paper. The distribution and characteristics of granite, tuff, clay stone, salt and loess in China are described, while maps showing the distribution of host rocks are presented. Because of the wide distribution, large scale, good heat conductivity and suitable mechanical properties, granite is considered as the most potential host rock. Some granite bodies distributed in NW China, SW China, South China and Inner Mongolia have been selected as potential areas. Detailed site characterization at Beishan area, Gansu Province NW China is in progress

Methods and results of the investigation of the thermomechanical behaviour of rock salt with regard to the final disposal of high-level radioactive wastes

International Nuclear Information System (INIS)

Wieczorek, K.; Klarr, K.

1993-01-01

This report summarizes the knowledge about thermal and mechanical behaviour of rock salt that has been accumulated by various R and D institutions in Germany from laboratory and in situ investigations. An important objective is to give a comprehensive overview of the investigation methods and instruments available and to discuss these methods and instruments with regard to their applicability and reliability for the investigation of the thermomechanical effects of high level radioactive waste emplacement in rock salt formations. The report is focused on the activities of the GSF-Institut fur Tieflagerung in the Asse mine regarding the disposal of high and intermediate level radioactive waste during the last decades. The design and the results of the most important in situ experiments are presented and discussed in detail. The results are compared to model calculations in order to evaluate the reliability of both the measurements and the calculation results. The relevance of the results for the situation in Spain is discussed in a separate chapter. As the investigations in Germany have been performed in domal salt, while the Spanish concept is based on waste disposal in bedded salt, significant differences in the thermomechanical behaviour cannot be excluded. The investigation methods, however, will be applicable. (Author)

Core Cutting Test with Vertical Rock Cutting Rig (VRCR)

Science.gov (United States)

Yasar, Serdar; Osman Yilmaz, Ali

2017-12-01

Roadheaders are frequently used machines in mining and tunnelling, and performance prediction of roadheaders is important for project economics and stability. Several methods were proposed so far for this purpose and, rock cutting tests are the best choice. Rock cutting tests are generally divided into two groups which are namely, full scale rock cutting tests and small scale rock cutting tests. These two tests have some superiorities and deficiencies over themselves. However, in many cases, where rock sampling becomes problematic, small scale rock cutting test (core cutting test) is preferred for performance prediction, since small block samples and core samples can be conducted to rock cutting testing. Common problem for rock cutting tests are that they can be found in very limited research centres. In this study, a new mobile rock cutting testing equipment, vertical rock cutting rig (VRCR) was introduced. Standard testing procedure was conducted on seven rock samples which were the part of a former study on cutting rocks with another small scale rock cutting test. Results showed that core cutting test can be realized successfully with VRCR with the validation of paired samples t-test.

The disposal of Canada's nuclear fuel waste: a study of postclosure safety of in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock volume 1: summary

International Nuclear Information System (INIS)

Wikjord, A.G.; Baumgartner, P.; Johnson, L.H.; Stanchell, F.W.; Zach, R.; Goodwin, B.W.

1996-06-01

The concept for disposal of Canada's nuclear fuel waste involves isolating the waste in corrosion-resistant containers emplaced and sealed within a vault at a depth of 500 to 1000 m in plutonic rock of the Canadian Shield. The case for the acceptability of the concept as a means of safely disposing of Canada's nuclear fuel waste is presented in an Environmental Impact Statement (EIS) The disposal concept permits a choice of methods, materials, site locations and designs. The EIS presents a case study of the long-term (i.e., postclosure) performance of a hypothetical implementation of the concept, referred to in this report as the reference disposal system. The reference disposal system is based on borehole emplacement of used CANDU fuel in Grade-2 titanium alloy containers in low-permeability, sparsely fractured plutonic rock of the Canadian Shield. We evaluate the long-term performance of another hypothetical implementation of the concept based on in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock. The geological characteristics of the geosphere assumed for this study result in short groundwater travel times from the disposal vault to the surface. In the present study, the principal barrier to the movement of contaminants is the long-lasting copper container. We show that the long-lasting container can effectively compensate for a permeable host rock which results in an unfavourable groundwater flow condition. These studies illustrate the flexibility of AECL's disposal concept to take advantage of the retention, delay, dispersion, dilution and radioactive decay of contaminants in a system of natural barriers provided by the geosphere and hydrosphere and of engineered barriers provided by the waste form, container, buffer, backfills, other vault seals and grouts. In an actual implementation, the engineered system would be designed for the geological conditions encountered at the host site. 34 refs., 2 tabs., 11 figs

Deep fracturation of granitic rock mass

International Nuclear Information System (INIS)

Bles, J.L.; Blanchin, R.; Bonijoly, D.; Dutartre, P.; Feybesse, J.L.; Gros, Y.; Landry, J.; Martin, P.

1986-01-01

This documentary study realized with the financial support of the European Communities and the CEA aims at the utilization of available data for the understanding of the evolution of natural fractures in granitic rocks from the surface to deep underground, in various feasibility studies dealing with radioactive wastes disposal. The Mont Blanc road tunnel, the EDF Arc-Isere gallerie, the Auriat deep borehole and the Pyrenean rock mass of Bassies are studied. In this study are more particularly analyzed the relationship between small fractures and large faults, evolution with depth of fracture density and direction, consequences of rock decompression and relationship between fracturation and groundwater [fr

Measurement of diffusive properties of intact rock

Energy Technology Data Exchange (ETDEWEB)

Harvey, K B

1996-12-01

In the Postclosure Assessment of a Reference System for the Disposal of Canada`s Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the `exclusion zone.` A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D{sub o}) for {sup 129}1 and {sup 14}C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D{sup i}) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs.

Measurement of diffusive properties of intact rock

International Nuclear Information System (INIS)

Harvey, K.B.

1996-12-01

In the Postclosure Assessment of a Reference System for the Disposal of Canada's Nuclear Fuel Waste (Goodwin et al. 1994) the disposal vault is assumed to be surrounded by a zone of intact rock, referred to as the 'exclusion zone.' A sensitivity analysis of the relative effectiveness of the several engineered and natural barriers that contribute to the safety of the reference disposal system has shown that this zone of intact rock is the most effective of these barriers to the movement of radionuclides through the reference system. Peer review of the geosphere model used in the case study for the EIS (Environmental Impact Statement) of the Canadian Nuclear Fuel Waste Management Program has identified the need to quantify the properties of the intact rock surrounding the disposal vault that would control the transport of radionuclides by diffusion. The Postclosure Assessment also identified the need for appropriate values of the free water diffusion coefficient (D o ) for 129 1 and 14 C. The measurement of rock resistivity allows the calculation of the Formation Factor for a rock This review describes the Formation Factor, diffusivity, permeability, and porosity, and how these properties might be measured or inferred for insitu rock under the conditions that apply to the intact rock surrounding a potential disposal vault. The importance of measuring the intrinsic diffusion coefficient (D i ) of diffusing species under solution salinities simulating those of groundwaters is emphasised, and a method of measurement is described that is independent of the diffusing medium, and which would be appropriate for measurements made in chemically complex media such as groundwaters. (author). 95 refs., 4 tabs., 39 figs

Mechanical dispersion in fractured crystalline rock systems

International Nuclear Information System (INIS)

Lafleur, D.W.; Raven, K.G.

1986-12-01

This report compiles and evaluates the hydrogeologic parameters describing the flow of groundwater and transport of solutes in fractured crystalline rocks. This report describes the processes of mechanical dispersion in fractured crystalline rocks, and compiles and evaluates the dispersion parameters determined from both laboratory and field tracer experiments. The compiled data show that extrapolation of the reliable test results performed over intermediate scales (10's of m and 10's to 100's of hours) to larger spatial and temporal scales required for performance assessment of a nuclear waste repository in crystalline rock is not justified. The reliable measures of longitudinal dispersivity of fractured crystalline rock are found to range between 0.4 and 7.8 m

Thermo-hydro-mechanical modelling of fractured rock masses application to radioactive wastes storage

International Nuclear Information System (INIS)

Vuillod, E.

1995-01-01

This work belongs to the Decovalex project (international cooperative project for the development of coupled models and their validation against experiments in nuclear waste isolation) of thermo-hydro-mechanical (THM) modeling of fractured rock massifs inside which high level radioactive waste disposal sites are simulated. The mathematical laws controlling the behaviour of the environment are resolved analytically in the case of a continuous environment (definition of an equivalent environment) and numerically if the environment is discontinuous (modeling of joints behaviour). The coupled THM models strongly influence the behaviour of a model. Modeling performed with the UDEC code shows the importance of HM couplings depending on whether the calculations are made in permanent or transient regime, and the influence of the loading path in the case of TM modeling. The geometry of fractures also influences the behaviour of the model. Studying the connexity of a fractures network allows to determine its degree of homogeneity. The comparison between two methods, continuous environment and discontinuous environment, has been carried out by determining the permeability tensor and the stress-deformation relations on fractured test-samples. It shows the differences in behaviour between an homogenized environment and a discrete environment. Finally two exercises of THM modeling of radioactive waste disposal sites illustrate the researches carried out. A far field model has permitted to compare the results obtained with calculation codes using different logics. The second model, a near field one, focusses more on the importance played by fracturing on the behaviour of the massif. The high density of the reference network has required some mathematical developments, in order to determine the representative equivalent volume (continuous approaches), and some mathematical analyses, to correctly simplify the environment (discontinuous approaches). These methods and analyses are

Characterisation of gas transport properties of the Opalinus clay, a potential host rock formation for radioactive waste disposal

International Nuclear Information System (INIS)

Marschall, P.; Horseman, S.; Gimmi, T.

2005-01-01

The Opalinus Clay in Northern Switzerland has been identified as a potential host rock formation for the disposal of radioactive waste. Comprehensive understanding of gas transport processes through this low-permeability formation forms a key issue in the assessment of repository performance. Field investigations and laboratory experiments suggest an intrinsic permeability of the Opalinus Clay in the order of 10 -20 to 10 -21 m 2 and a moderate anisotropy ratio ≤ 10. Porosity depends on clay content and burial depth; values of ∼ 0.12 are reported for the region of interest. Porosimetry indicates that about 10-30% of voids can be classed as macro-pores, corresponding to an equivalent pore radius > 25 nm. The determined entry pressures are in the range of 0.4-10 MPa and exhibit a marked dependence on intrinsic permeability. Both in situ gas tests and gas permeameter tests on drill-cores demonstrate that gas transport through the rock is accompanied by pore water displacement, suggesting that classical flow concepts of immiscible displacement in porous media can be applied when the gas entry pressure (i.e. capillary threshold pressure) is less than the minimum principal stress acting within the rock. Essentially, the pore space accessible to gas flow is restricted to the network of connected macro-pores, which implies a very low degree of desaturation of the rock during the gas imbibition process. At elevated gas pressures (i.e. when gas pressure approaches the level of total stress that acts on the rock body), evidence was seen for dilatancy controlled gas transport mechanisms. Further field experiments were aimed at creating extended tensile fractures with high fracture transmissivity (hydro- or gas-fractures). The test results lead to the conclusion that gas fracturing can be largely ruled out as a risk for post-closure repository performance. (authors)

Nuclear waste management by in-situ melting

International Nuclear Information System (INIS)

Angelo, J.A. Jr.

1976-01-01

A systematic assessment of the in-situ melting concept as an ultimate waste disposal option shows that the placement of solidifed, high-level radioactive wastes in an in-situ melting cavity with a crushed rock backfill not only eliminates the major deficiencies inherent in other in-situ melting schemes, but also satisfies reasonable criteria for ultimate disposal. In-situ melting reduces the waste isolation time requirements to several hundred years. Calculated spent fuel and processing waste afterheat values assess the role of actinide and cladding material nuclides in creating the total afterheat and provide quantitative variation with time for these values for contamporary and advanced-design fission reactors. The dominant roles of 134 Cs in thermal spectrum reactor afterheats during the first decade of cooling of the actinide nuclides in all typical waste after-heats following a century or two of cooling are identified. The spatial and temporal behavior of a spherically symmetric waste repository experiencing in-situ melting in an equal density, homogeneous medium for silicate rock and salt is controlled primarily by the overall volumetric thermal source strength, the time-dependent characteristics of the high-level wastes, and the thermophysical properties of the surrounding rock environment. Calculations were verified by experimental data. The hazard index for typical high-level wastes is dominated by the fission product nuclides for the first three centuries of decay. It is then controlled by the actinides, especially americium, which dominates for 10,000 years. With in-situ melting, the hazard index for the re-solidifed rock/waste matrix deepunderground falls below the hazard index of naturally occurring uranium ore bodies within a few hundred years, whether or not the more hazardous actinide nuclides are selectively removed from the wastes prior to storage

Rock fracture dynamics research at AECL's Underground Research Laboratory: applications to geological disposal of radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Young, R.P. [Univ. of Toronto, Toronto, ON (Canada); Haycox, J.R. [Applied Seismology Consultants Limited, Shrewsbury, Shropshire (United Kingdom); Martino, J. [Atomic Energy of Canada Limited, Pinawa, MB (Canada)

2011-07-01

Studies of rock fracture dynamics at AECL's Underground Research Laboratory (URL) have helped to provide a fundamental understanding of how crystalline rock responds to stresses induced from excavation, pressurization and temperature changes. The data acquired continue to provide insights into how a facility for the future geological disposal of radioactive waste could be engineered. Research into microseismic (MS), acoustic emission (AE), and ultrasonic velocity measurements has been performed on the full-scale sealed, pressurized, and heated horizontal elliptical tunnel at the Tunnel Sealing Experiment (TSX). The continuous monitoring of the experiment for 8 years provides a unique dataset for the understanding of the medium-term performance of an engineered disposal facility. This paper summarizes the results, interpretations and key findings of the experiment paying particular focus to the heating and cooling/depressurization of the chamber. Initial drilling of the tunnel and bulkheads causes microfracturing around the tunnel, mapped by MS and AEs, and is used as a benchmark for fracturing representing the excavated damaged zone (EDZ). There is no further extension to the volume during pressurization or heating of the tunnel suggesting an increase in crack density and coalescence of cracks rather than extension into unfractured rock. The dominant structure within the seismic cloud has been investigated using a statistical approach applying the three-point method. MS events in the roof exhibit a dominant pattern of sub-horizontal and shallow-dipping well defined planar features, but during cooling and depressurization a 45 degree dip normal to the tunnel axis is observed, which may be caused by movement in the rock-concrete interface due to differential cooling of the bulkhead and host rock. Cooling and depressurization of the TSX have not led to a significant increase in the number of MS or AE events. Ultrasonic results suggest the rock gets even stiffer

Effects of tuff waste package components on release from 76-68 simulated waste glass: Final report

International Nuclear Information System (INIS)

McVay, G.L.; Robinson, G.R.

1984-04-01

An experimental matrix has been conducted that will allow evaluation of the effects of waste package constituents on the waste form release behavior in a tuff repository environment. Tuff rock and groundwater were used along with 304L, 316, and 1020M ferrous metals to evaluate release from uranium-doped MCC 76-68 simulated waste glass. One of the major findings was that in the absence of 1020M mild steel, tuff rock powder dominates the system. However, when 1020M mild steel is present, it appears to dominate the system. The rock-dominated system results in suppressed glass-water reaction and leaching while the 1020M-dominated system results in enhanced leaching - but the metal effectively scavenges uranium from solution. The 300-series stainless steels play no significant role in affecting glass leaching characteristics. 6 refs., 28 figs., 5 tabs

Preliminary rock mechanics laboratory: Investigation plan

International Nuclear Information System (INIS)

Oschman, K.P.; Hummeldorf, R.G.; Hume, H.R.; Karakouzian, M.; Vakili, J.E.

1987-01-01

This document presents the rationale for rock mechanics laboratory testing (including the supporting analysis and numerical modeling) planned for the site characterization of a nuclear waste repository in salt. This plan first identifies what information is required for regulatory and design purposes, and then presents the rationale for the testing that satisfies the required information needs. A preliminary estimate of the minimum sampling requirements for rock laboratory testing during site characterization is also presented. Periodic revision of this document is planned

Penetration of liquid fingers into superheated fractured rock

Science.gov (United States)

Birkholzer, Jens

2003-04-01

Water infiltrating down a fracture in unsaturated rock experiences complex fluid flow and heat transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new efficient semianalytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest.

Penetration of liquid fingers into superheated fractured rock

International Nuclear Information System (INIS)

Birkholzer, Jens

2002-01-01

Water infiltrating down a fracture in unsaturated rock experiences complex fluid-flow and heat-transfer phenomena when entering above-boiling rock temperature regions. Such conditions are expected, for example, after emplacement of heat-generating nuclear waste in underground repositories. A new, efficient semi-analytical method is proposed in this paper that simulates the flow processes of infiltration events subject to vigorous boiling from the adjacent hot rock. It is assumed that liquid flow forms in localized preferential flow paths, and that infiltration events are typically short in duration but large in magnitude relative to the average net infiltration. The new solution scheme is applied to several test cases studying sensitivity to a variety of input parameters. Sample simulations are performed for conditions representative of the potential nuclear waste repository at Yucca Mountain, Nevada. A characteristic parameter is introduced that provides a quick estimate of the relative significance of boiling at a given location of interest

The Ypresian clays as alternative host rock for radioactive waste disposal in Belgium. A transferability study

International Nuclear Information System (INIS)

Van Baelen, Herve; Wouters, Laurent; Brassinnes, Stephane; Van Geet, Maarten; Vandenberghe, Noel

2012-01-01

Document available in extended abstract form only. For the long-term management of high-level and/or long-lived radioactive waste, ONDRAF/NIRAS advises deep geological repository in a plastic clay host rock. Since the seventies, Oligocene Boom Clay has been extensively studied for this purpose and is, in the Belgian context, considered as the reference host rock with Mol as the reference site for the RD and D. The alternative host rock, the Ypresian clays, has been studied for their basic properties, from the late nineties onwards, with Doel as reference site. This study aims at determining to which extent methodologies, knowledge and know-how can be transferred from Boom Clay to the Ypresian clays, in order to enhance the knowledge of this alternative without excessive research efforts. It evaluates the present knowledge of the Ypresian clays and figures out which elements are sufficiently known and understood, which elements of the Boom Clay can be reused and which need additional research. The Ypresian clays refer to a nearly continuous sequence of non-indurated, clayey layers, deposited early in the Eocene, in an open marine basin. It has a total thickness of 100 m or more and, in the area of interest, it occurs at a few hundreds of meters depth. Apart from a very slight tilt to the north, no major structures are known to affect the Ypresian clays in the investigated area. The lateral continuity inside the Ypresian clays might, however, be compromised by the potential occurrence of small-scale intra-formational faults. Two drilling campaigns, carried out in the framework of potential radioactive waste disposal, allowed to collect new data and describe and compare the Ypresian clays relative to Boom Clay. The grain size distribution of both clays is comparable. Although the minerals they are composed of are the same, the relative proportions within the clay fraction are significantly different, the Ypresian clays containing more smectite and swelling mixed

Diffusion of water, cesium and neptunium in pores of rocks

International Nuclear Information System (INIS)

Puukko, E.; Heikkinen, T.; Hakanen, M.

1993-10-01

Teollisuuden Voima Oy (TVO) is investigating the feasibility to dispose of spent nuclear fuel within Finland. The present plan calls for the repository to be located in crystalline rock at a depth of several hundred meters. The safety assessment of the repository includes calculations of migration of waste nuclides. The flow of waste elements in groundwater will be retarded through sorption interaction with minerals and through diffusion into rock. Diffusion is the only mechanism retarding the migration of non-sorbing species and, it is expected to be the dominating retardation mechanism of many of the sorbing elements. In the investigation the simultaneous diffusion of tritiated water (HTO), cesium and neptunium in rocks of TVO investigation sites at Kivetty, Olkiluoto and Romuvaara were studied. (11 refs., 33 figs., 9 tabs.)

Influence of deformation on the fluid transport properties of salt rocks

NARCIS (Netherlands)

Peach, C.J.

1991-01-01

While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They

MANAGEMENT AND TREATMENT OF WATER FROM HARD-ROCK MINES {ENGINEERING ISSUE}

Science.gov (United States)

This Engineering Issue document on treatment of mining waters is a practical guide to understanding and selecting technologies for the environmental management of waste materials and effluents at hard-rock mines. For the purposes of this discussion, hard-rock mining primarily ref...

A model for the description of oxidation in sulfidic waste rock dumps

International Nuclear Information System (INIS)

Bennett, J. W.; Pantelis, G.; Ritchie, A.I.M.; Stepanyants, Y.A.

2000-03-01

Basic mathematical equations which describe the processes of sulfide oxidation and gas and water transport in waste rock dumps are presented and discussed. The governing equations account for gas and water flow, vaporisation and condensation with latent heat effects, heat transport and mass balance. Gas, water and solid phases are assumed to be in local thermal equilibrium at all times. Air is approximated as an ideal three-component gas. Different semi-empirical relationships between physical values are used: Darcy's law for fluid flow, ideal gas law, the Van Genuchten formula for the relationship between degree of water saturation and pressure head, Mualem's formula for the relative hydraulic conductivity as a function of pressure head, etc. Some important global quantities, such as the fraction of sulfide sulfur oxidised and the global oxidation rate, are defined and considered as functions of time. The full set of equations is collected and presented in explicit form, convenient for further numerical modelling. The glossary of some technical terms and the table of definitions of the main parameters as well as their units and characteristic values are given

Engineering geology of waste disposal

International Nuclear Information System (INIS)

Bentley, S.P.

1996-01-01

This volume covers a wide spectrum of activities in the field of waste disposal. These activities range from design of new landfills and containment properties of natural clays to investigation, hazard assessment and remediation of existing landfills. Consideration is given to design criteria for hard rock quarries when used for waste disposal. In addition, an entire section concerns the geotechnics of underground repositories. This covers such topics as deep drilling, in situ stress measurement, rock mass characterization, groundwater flows and barrier design. Engineering Geology of Waste Disposal examines, in detail, the active role of engineering geologists in the design of waste disposal facilities on UK and international projects. The book provides an authoritative mix of overviews and detailed case histories. The extensive spectrum of papers will be of practical value to those geologists, engineers and environmental scientists who are directly involved with waste disposal. (UK)

Thermal effects on clay rocks for deep disposal of high-level radioactive waste

Directory of Open Access Journals (Sweden)

Chun-Liang Zhang

2017-06-01

Full Text Available Thermal effects on the Callovo-Oxfordian and Opalinus clay rocks for hosting high-level radioactive waste were comprehensively investigated with laboratory and in situ experiments under repository relevant conditions: (1 stresses covering the range from the initial lithostatic state to redistributed levels after excavation, (2 hydraulic drained and undrained boundaries, and (3 heating from ambient temperature up to 90 °C–120 °C and a subsequent cooling phase. The laboratory experiments were performed on normal-sized and large hollow cylindrical samples in various respects of thermal expansion and contraction, thermally-induced pore water pressure, temperature influences on deformation and strength, thermal impacts on swelling, fracture sealing and permeability. The laboratory results obtained from the samples are consistent with the in situ observations during heating experiments in the underground research laboratories at Bure and Mont-Terri. Even though the claystones showed significant responses to thermal loading, no negative effects on their favorable barrier properties were observed.

Panel discussion on rock mechanics issues in repository design

International Nuclear Information System (INIS)

Bieniawski, Z.T.; Kim, K.S.; Nataraja, M.

1996-01-01

The panel discussion was introduced by Mr. Z.T.(Richard) Bieniawski and then continued with five additional speakers. The topics covered in the discussion included rock mechanics pertaining to the design of underground facilities for the disposal of radioactive wastes and the safety of such facilities. The speakers included: Mr. Kun-Soo Kim who is a specialist in the area of rock mechanics testing during the Basalt Waste Isolation Project; Dr. Mysore Nataraja who is the senior project manager with the NRC; Dr. Michael Voegele who is the project manager for Science Applications International Corporation (SAIC) on the Yucca Mountain Project; Dr. Edward Cording who is a member of the Nuclear Waste Technical Review Board; and Dr. Hemendra Kalia who is employed by Los Alamos National Laboratory and coordinates various activities of testing programs at the Yucca Mountain Site

Introduction to numerical modeling of thermohydrologic flow in fractured rock masses

International Nuclear Information System (INIS)

Wang, J.S.Y.

1980-01-01

More attention is being given to the possibility of nuclear waste isolation in hard rock formations. The waste will generate heat which raises the temperature of the surrounding fractured rock masses and induces buoyancy flow and pressure change in the fluid. These effects introduce the potential hazard of radionuclides being carried to the biosphere, and affect the structure of a repository by stress changes in the rock formation. The thermohydrological and thermomechanical responses are determined by the fractures as well as the intact rock blocks. The capability of modeling fractured rock masses is essential to site characterization and repository evaluation. The fractures can be modeled either as a discrete system, taking into account the detailed fracture distributions, or as a continuum representing the spatial average of the fractures. A numerical model is characterized by the governing equations, the numerical methods, the computer codes, the validations, and the applications. These elements of the thermohydrological models are discussed. Along with the general review, some of the considerations in modeling fractures are also discussed. Some remarks on the research needs in modeling fractured rock mass conclude the paper

Dynamic response of tunnels in jointed rocks

International Nuclear Information System (INIS)

Heuze, F.E.; Shaffer, R.J.; Walton, O.R.; Maddix, D.M.

1992-03-01

We describe the application of the Discrete Element Method (DEM) to the dynamic analysis of the response of tunnels in jointed rocks to earthquake loading. In situations where large motions of many blocks and collapse occur, the discontinuum-based DEM approach appears superior to other methods of analysis

Redox front penetration in the fractured Toki Granite, central Japan: An analogue for redox reactions and redox buffering in fractured crystalline host rocks for repositories of long-lived radioactive waste

International Nuclear Information System (INIS)

Yamamoto, Koshi; Yoshida, Hidekazu; Akagawa, Fuminori; Nishimoto, Shoji; Metcalfe, Richard

2013-01-01

Highlights: • Deep redox front developed in orogenic granitic rock have been studied. • The process was controlled by the buffering capacity of minerals. • This is an analogue of redox front penetration into HLW repositories in Japan. - Abstract: Redox buffering is one important factor to be considered when assessing the barrier function of potential host rocks for a deep geological repository for long-lived radioactive waste. If such a repository is to be sited in fractured crystalline host rock it must be demonstrated that waste will be emplaced deeper than the maximum depth to which oxidizing waters can penetrate from the earth’s surface via fractures, during the assessment timeframe (typically 1 Ma). An analogue for penetration of such oxidizing water occurs in the Cretaceous Toki Granite of central Japan. Here, a deep redox front is developed along water-conducting fractures at a depth of 210 m below the ground surface. Detailed petrographical studies and geochemical analyses were carried out on drill core specimens of this redox front. The aim was to determine the buffering processes and behavior of major and minor elements, including rare earth elements (REEs), during redox front development. The results are compared with analytical data from an oxidized zone found along shallow fractures (up to 20 m from the surface) in the same granitic rock, in order to understand differences in elemental migration according to the depth below the ground surface of redox-front formation. Geochemical analyses by XRF and ICP-MS of the oxidized zone at 210 m depth reveal clear changes in Fe(III)/Fe(II) ratios and Ca depletion across the front, while Fe concentrations vary little. In contrast, the redox front identified along shallow fractures shows strong enrichments of Fe, Mn and trace elements in the oxidized zone compared with the fresh rock matrix. The difference can be ascribed to the changing Eh and pH of groundwater as it flows downwards in the granite, due to

Summary of northern Atlantic coastal plain hydrology and its relation to disposal of high-level radioactive waste in buried crystalline rock; a preliminary appraisal

Science.gov (United States)

Lloyd, O.B.; Larson, J.D.; Davis, R.W.

1985-01-01

Interpretation of available hydrologic data suggests that some areas beneath the Coastal Plain in the States of Delaware, Maryland, New Jersey, North Carolina, and Virginia might have some potential for the disposal of nuclear waste in crystalline rock that is buried beneath the Coastal Plain sediments. The areas of major interest occur where the top of the basement rock lies between 1,000 and 4,000 feet below sea level, the aquifer(s) immediately above the basement rock are saturated with saline water, confining material overlies the saline water bearing aquifer(s), and groundwater flow in the saline water aquifer(s) can be established. Preliminary data on (1) the distribution and thickness of the lowermost aquifers and confining beds, (2) the distribution of hydraulic conductivity in the lowermost aquifers, (3) estimated hydraulic heads and inferred direction of lateral groundwater flow for 1980, and (4) the distribution of saline water and brine, indicate eastern parts of the study area relatively best meet most of the criteria proposed for sediments that would overlie any potential buried crystalline-rock disposal site.

Rock waste dumps on the Davydov Glacier (Akshyirak Range, Tien Shan

Directory of Open Access Journals (Sweden)

V. A. Kuzmichenok

2012-01-01

Full Text Available Since 1995, a barren rock has been formed at the Davydov Glacier, due to the works at the Kumtor Gold Mine. By the end of 2010, total amount of the rock, stockpiled on the glacier, apparently exceeded 200 million tons, the height of dumps of rock sometimes exceeded 50 meters. The most noticeable effects of this are provoking local surges of the Davydov Glacier and squeezing glacier ice out of the dumps of rock. For a detailed analysis of both processes, we also used the results of periodic geodetic measurements (over 8000 of monitoring rods (about 800 rods of the gold mining company. A number of local surges of the glacier has been found, the first of which began in March–April 2002. To analyze glacier squeezing out of the dumps of rock, mathematical modeling of that process has been done. It was established that in most cases, the glacier is almost completely squeezed out of for 1–2 years.

Geological and rock mechanics aspects of the long-term evolution of a crystalline rock site

International Nuclear Information System (INIS)

Cosgrove, J.W.; Hudson, J.A.

2009-01-01

We consider the stability of a crystalline rock mass and hence the integrity of a radioactive waste repository contained therein by, firstly, identifying the geological evolution of such a site and, secondly, by assessing the likely rock mechanics consequences of the natural perturbations to the repository. In this way, the potency of an integrated geological-rock mechanics approach is demonstrated. The factors considered are the pre-repository geological evolution, the period of repository excavation, emplacement and closure, and the subsequent degradation and natural geological perturbations introduced by glacial loading. It is found that the additional rock stresses associated with glacial advance and retreat have a first order effect on the stress magnitudes and are likely to cause a radical change in the stress regime. There are many factors involved in the related geosphere stability and so the paper concludes with a systems diagram of the total evolutionary considerations before, during and after repository construction. (authors)

Stabilities of nuclear waste forms and their geochemical interactions in repositories

International Nuclear Information System (INIS)

White, W.B.

1980-01-01

The stabilities of high-level nuclear waste forms in a repository environment are briefly discussed. The advantages and disadvantages of such waste forms as borosilicate glass, supercalcine ceramics, and synthetic minerals are presented in context with the different rock types which have been proposed as possible host rocks for repositories. It is concluded that the growing geochemical evidence favors the use of a silicate rock repository because of the effectiveness of aluminosilicate rocks as chemical barriers for most radionuclides

Influence of deformation on the fluid transport properties of salt rocks

NARCIS (Netherlands)

Peach, C.J.

1991-01-01

While the fluid transport properties of rocks are well understood under hydrostatic conditions, little is known regarding these properties in rocks undergoing crystal plastic deformation. However, such data are needed as input in the field of radioactive waste disposal in salt formations. They are

Radiation damage studies on natural rock salt from various geological localities of interest to the radioactive waste disposal program

International Nuclear Information System (INIS)

Levy, P.W.

1981-01-01

As part of a program to investigate radiation damage in geological materials of interest to the radioactive waste disposal program, radiation damage, particularly radiation induced sodium metal colloid formation, has been studied in 14 natural rock salt samples. All measurements were made with equipment for making optical absorption and other measurements on samples, in a temperature controlled irradiation chamber, during and after 0.5 to 3.0 MeV electron irradiation. Samples were chosen for practical and scientific purposes, from localities that are potential repository sites and from different horizons at certain localities

Radioactive waste repository study

International Nuclear Information System (INIS)

1978-11-01

This is the second part of a report of a preliminary study for AECL. It considers the requirements for an underground waste repository for the disposal of wastes produced by the Canadian Nuclear Fuel Program. The following topics are discussed with reference to the repository: 1) geotechnical assessment, 2) hydrogeology and waste containment, 3) thermal loading and 4) rock mechanics. (author)

Modeling of Coupled Thermo-Hydro-Mechanical-Chemical Processes for Bentonite in a Clay-rock Repository for Heat-generating Nuclear Waste

Science.gov (United States)

Xu, H.; Rutqvist, J.; Zheng, L.; Birkholzer, J. T.

2016-12-01

Engineered Barrier Systems (EBS) that include a bentonite-based buffer are designed to isolate the high-level radioactive waste emplaced in tunnels in deep geological formations. The heat emanated from the waste can drive the moisture flow transport and induce strongly coupled Thermal (T), Hydrological (H), Mechanical (M) and Chemical (C) processes within the bentonite buffer and may also impact the evolution of the excavation disturbed zone and the sealing between the buffer and walls of an emplacement tunnel The flow and contaminant transport potential along the disturbed zone can be minimized by backfilling the tunnels with bentonite, if it provides enough swelling stress when hydrated by the host rock. The swelling capability of clay minerals within the bentonite is important for sealing gaps between bentonite block, and between the EBS and the surrounding host rock. However, a high temperature could result in chemical alteration of bentonite-based buffer and backfill materials through illitization, which may compromise the function of these EBS components by reducing their plasticity and capability to swell under wetting. Therefore, an adequate THMC coupling scheme is required to understand and to predict the changes of bentonite for identifying whether EBS bentonite can sustain higher temperatures. More comprehensive links between chemistry and mechanics, taking advantage of the framework provided by a dual-structure model, named Barcelona Expansive Model (BExM), was implemented in TOUGHREACT-FLAC3D and is used to simulate the response of EBS bentonite in in clay formation for a generic case. The current work is to evaluate the chemical changes in EBS bentonite and the effects on the bentonite swelling stress under high temperature. This work sheds light on the interaction between THMC processes, evaluates the potential deterioration of EBS bentonite and supports the decision making in the design of a nuclear waste repository in light of the maximum allowance

Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer soil cover

Science.gov (United States)

Song, Qing; Yanful, Ernest K.

2010-05-01

Engineered soil covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the soil cover. However, limited published information is available on the extent to which soil cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a soil cover. Two inclined (a slope of 20%) multilayer soil covers were examined under laboratory conditions. One cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other cover was a normal one without the channel pathway. The soil covers were installed in plastic boxes measuring 120 cm × 120 cm × 25 cm (width × height × thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The soil covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the soil cover without channel flow to 35.3% in the cover with channel flow, and percolation increased from zero in the normal soil cover to 43.0% of the total precipitation in the cover with channel flow. Gaseous oxygen transfer into the waste rock below the cover soils was 1091 times greater in the cover with channel than in the soil cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the soil cover. The spacing of the channel with respect to the length of the test box is similar to those

Characterizing and modelling the excavation damaged zone (EDZ) in crystalline rock in the context of radioactive waste disposal

International Nuclear Information System (INIS)

Hudson, J.A.; Backstrom, A.; Rutqvist, J.; Jing, L.; Backers, T.; Chijimatsu, M.; Christiansson, R.; Feng, X.-T.; Kobayashi, A.; Koyama, T.; Lee, H.-S.; Neretnieks, I.; Pan, P.Z.; Rinne, M.; Shen, B.-T.

2008-01-01

This paper describes current knowledge about the nature of and potential for thermo-hydro-mechanical-chemical modelling of the Excavation Damaged Zone (EDZ) around the excavations for an underground radioactive waste repository. In the first part of the paper, the disturbances associated with excavation are explained, together with reviews of Workshops that have been held on the subject. In the second part of the paper, the results of a DECOVALEX research programme on modelling the EDZ are presented. Four research teams used four different models to simulate the complete stress-strain curve for Avro granite from the Swedish Aespoe Hard Rock Laboratory. Subsequent research extended the work to computer simulation of the evolution of the repository using a 'wall block model' and a 'near-field model'. This included assessing the evolution of stress, failure and permeability and time dependent effects during repository evolution. As discussed, all the computer models are well suited to sensitivity studies for evaluating the influence of their respective supporting parameters on the complete stress-strain curve for rock and for modelling the EDZ

Characterising and modelling the excavation damaged zone (EDZ) in crystalline rock in the context of radioactive waste disposal

Energy Technology Data Exchange (ETDEWEB)

Hudson, J.A.; Backstrom, A.; Rutqvist, J.; Jing, L.; Backers, T.; Chijimatsu, M.; Christiansson, R.; Feng, X.-T.; Kobayashi, A.; Koyama, T.; Lee, H.-S.; Neretnieks, I.; Pan, P.Z.; Rinne, M.; Shen, B.-T.

2008-10-01

This paper describes current knowledge about the nature of and potential for thermo-hydro-mechanical-chemical modelling of the Excavation Damaged Zone (EDZ) around the excavations for an underground radioactive waste repository. In the first part of the paper, the disturbances associated with excavation are explained, together with reviews of Workshops that have been held on the subject. In the second part of the paper, the results of a DECOVALEX research programme on modelling the EDZ are presented. Four research teams used four different models to simulate the complete stress-strain curve for Avro granite from the Swedish Aespoe Hard Rock Laboratory. Subsequent research extended the work to computer simulation of the evolution of the repository using a 'wall block model' and a 'near-field model'. This included assessing the evolution of stress, failure and permeability and time dependent effects during repository evolution. As discussed, all the computer models are well suited to sensitivity studies for evaluating the influence of their respective supporting parameters on the complete stress-strain curve for rock and for modelling the EDZ.

Solutions for Waste Management

International Nuclear Information System (INIS)

2013-01-01

To safely and securely dispose of highlevel and long-lived radioactive waste, this material needs to be stored for a period of time that is very long compared to our everyday experience. Underground disposal facilities need to be designed and constructed in suitable geological conditions that can be confidently demonstrated to contain and isolate the hazardous waste from our environment for hundreds of thousands of years. Over this period of time, during which the safety of an underground waste repository system must be assured, the waste's radioactivity will decay to a level that cannot pose a danger to people or the environment. The archaeological record can help in visualizing such a long period of time. Climates change, oceans rise and vanish, and species evolve in the course of a one hundred millennia. Rocks bear witness to all of these changes. Geologists in their search for safe repositories for the long-term disposal of high level radioactive waste have identified rock formations that have proven stable for millions of years. These geological formations are expected to remain stable for millions of years and can serve as host formations for waste repositories.

Underground disposal of high active waste

International Nuclear Information System (INIS)

Engelmann, H.J.

1982-01-01

This paper is concerned with the engineering aspects relating to the deep burial of high active waste in stable geological formations. The design of a repository depends upon a number of factors not least of which is the type of rock in which it is to be constructed. High level wastes must be isolated from man's environment for such periods that subsequent release will not result in an unacceptable hazard to human population. Design aspects of repositories are reviewed and conceptual design are present in relation to the geological formations under consideration. Over long time periods the most probable mode of release of radionuclides is through groundwater contacting the waste. The proposed concepts therefore include the use of engineered and natural barriers to delay the eventual release of waterborne radionuclides into mans environment. In all cases the ultimate barrier will be the geological formation. Nevertheless, depending upon the type of host rock, use will be made of various additional engineered barriers to delay water contacting the high level waste for several hundreds of years. During this time the level of radiation and associated heat emitted by the waste, will fall by several orders of magnitude and the rock temperatures within a repository will be returning to ambient. Thereafter the residual activity will mainly arise from the actinides. Containment may be enhanced by surrounding the canisters with materials having high sorption capabilities for many of the radionuclides involved. The depth at which a repository is excavated must be sufficient to ensure that the overburden will withstand changes in environmental conditions. The depth of cover required in different rock types may vary. In clay excavating at depth of up to -250 m appears feasible, while in hard rocks and salts working at depth of up to -1000 m is entirely practicable. (orig./RW)

Permeability of natural rock salt from the Waste Isolation Pilot Plant (WIPP) during damage evolution and healing

International Nuclear Information System (INIS)

Pfeifle, T.W.; Hurtado, L.D.

1998-06-01

The US Department of Energy has developed the Waste Isolation Pilot Plant (WIPP) in the bedded salt of southeastern New Mexico to demonstrate the safe disposal of radioactive transuranic wastes. Four vertical shafts provide access to the underground workings located at a depth of about 660 meters. These shafts connect the underground facility to the surface and potentially provide communication between lithologic units, so they will be sealed to limit both the release of hazardous waste from and fluid flow into the repository. The seal design must consider the potential for fluid flow through a disturbed rock zone (DRZ) that develops in the salt near the shafts. The DRZ, which forms initially during excavation and then evolves with time, is expected to have higher permeability than the native salt. The closure of the shaft openings (i.e., through salt creep) will compress the seals, thereby inducing a compressive back-stress on the DRZ. This back-stress is expected to arrest the evolution of the DRZ, and with time will promote healing of damage. This paper presents laboratory data from tertiary creep and hydrostatic compression tests designed to characterize damage evolution and healing in WIPP salt. Healing is quantified in terms of permanent reduction in permeability, and the data are used to estimate healing times based on considerations of first-order kinetics

Igneous Rocks

Science.gov (United States)

Doe, Bruce R.

“Igneous Rocks was written for undergraduate geology majors who have had a year of college-level chemistry and a course in mineralogy … and for beginning graduate students. Geologists working in industry, government, or academia should find this text useful as a guide to the technical literature up to 1981 and as an overview of topics with which they have not worked but which may have unanticipated pertinence to their own projects.” So starts the preface to this textbook.As one who works part time in research on igneous rocks, especially as they relate to mineral deposits, I have been looking for such a book with this avowed purpose in a field that has a choking richness of evolving terminology and a bewildering volume of interdisciplinary literature. In addition to the standard topics of igneous petrology, the book contains a chapter on the role of igneous activity in the genesis of mineral deposits, its value to geothermal energy, and the potential of igneous rocks as an environment for nuclear waste disposal. These topics are presented rather apologetically in the preface, but the author is to be applauded for including this chapter. The apology shows just how new these interests are to petrology. Recognition is finally coming that, for example, mineral deposits are not “sports of nature,” a view held even by many economic geologists as recently as the early 1960's; instead they are perfectly ordinary geochemical features formed by perfectly ordinary geologic processes. In fact, the mineral deposits and their attendant alteration zones probably have as much to tell us about igneous rocks as the igneous rocks have to tell us about mineral deposits.

Petrophysics at the rock matrix scale: hydraulic properties and petrographic interpretation

International Nuclear Information System (INIS)

Montoto, M.

2003-01-01

The main objective of this publication is to review, summarize and make comprehensive the hydraulic properties of rocks, at the rock matrix or in tact rock scale. Also to describe how to petrographically interpret those properties. For this purpose, the procedures for the characterization and visualisation of the rock-forming components and in special the water path-ways at that scale are explained. Further more, to establish a methodological approach for an appropriate petrographic interpretation of all the mentioned properties is intended. This Technical Report is applied to the geological solution for the final disposal of high level radioactive wastes. In any case, most of the aspects covered here are of scientific and technical interest for any researcher interested in the behaviour of water in rocks and vice versa, also in the potential fluid- rock interactions. The document is divided into six Chapters, mainly theoretical and methodological, and six Appen - dixes, more focussed to practical tests and procedures for rock characterization. Two significant rock types in high level radioactive waste, HLW, granites and clays, have been used for illustrating most of the examples here included. Under a wide geological perspective, it must be stated that in any geological scenario two different systems or scales coexist; the rock massif (with fractures of about m to km) and the rock matrix (with internal discontinuities such as fissures and cracks to the order of Fm to dm). Their different behaviour is considered in Chapter 1 as well as the specific role played by the rock matrix in the long- and short-term period. General considerations about physical properties of rocks and comparative advantages and disadvantages of the main candidate rocks for radioactive repositories are also included. (Author)

Radioactive waste containment - a literature study

International Nuclear Information System (INIS)

Mohiuddin, G.

1985-01-01

One of the basic requirements of safe radioactive waste disposal is isolation of the radioactive substances to prevent leakage into the biosphere. The multi-barrier concept has been developed to meet this requirement. Within the framework of the concept, barriers can be either natural or man-made. Natural barriers, i.e. geologic formations,have been investigated for their suitability, with host rock and their different properties being determined and compared. It has been found that the qualification of a proposed repository medium cannot be defined on the basis of physical, chemical, and mineralogical criteria alone, but that these data have to be completed by a global evaluation of the entire system consisting of waste products and waste forms, host rock, and surrounding rock. The study in hand reviews the reports and also lists the studies made on engineered barriers, as e.g. immobilisation barriers, container and package barriers, of various waste forms. A review of the studies dealing with the various waste disposal techniques shows that the sub-surface waste disposal and the deep underground disposal in mines are the best developed techniques currently. A review of ultimate disposal concepts adopted abroad shows that most countries favour the mining technology approach, with the exception of Denmark where R and D work in this field is focused on deep well disposal. (orig./HP) [de

The Mont Terri rock laboratory: International research in the Opalinus Clay

International Nuclear Information System (INIS)

Bossart, P.

2015-01-01

This article reports on a visit made to the rock laboratory in Mont Terri, Switzerland, where research is being done concerning rock materials that can possibly be used for the implementation of repositories for nuclear wastes. Emphasis is placed on the project’s organisation, rock geology and on-going experiments. International organisations also involved in research on nuclear waste repositories are listed. The research facilities in tunnels built in Opalinus Clay at the Mont Terri site are described. The geology of Opalinus Clay and the structures found in the research tunnels are discussed, as is the hydro-geological setting. The research programme and various institutions involved are listed and experiments carried out are noted. The facilities are now also being used for research on topics related to carbon sequestration

Final workshop proceedings of the collaborative project ''Crystalline ROCK retention processes''

Energy Technology Data Exchange (ETDEWEB)

Rabung, Thomas; Garcia, David; Montoya Vanessa; Molinero, Jorge (eds.)

2014-07-01

The present document is the proceedings of the Final Workshop of the EURATOM FP7 Collaborative Project CROCK (Crystalline Rock Retention Processes). The key driver for initiation the CP CROCK, identified by national Waste Management Organizations, is the undesired high uncertainty and the associated conservatism with respect to the radionuclide transport in the crystalline host-rock far-field around geological disposal of high-level radioactive wastes.

Nuclear waste repository in basalt: a design description

International Nuclear Information System (INIS)

Ritchie, J.S.; Schmidt, B.

1982-01-01

The conceptual design of a nuclear waste repository in basalt is described. Nuclear waste packages are placed in holes drilled into the floor of tunnels at a depth of 3700 ft. About 100 miles of tunnels are required to receive 35,000 packages. Five shafts bring waste packages, ventilation air, excavated rock, personnel, material, and services to and from the subsurface. The most important surface facility is the waste handling building, located over the waste handling shaft, where waste is received and packaged for storage. Two independent ventilation systems are provided to avoid potential contamination of spaces that do not contain nuclear waste. Because of the high temperatures at depth, an elaborate air chilling system is provided. Because the waste packages deliver a considerable amount of heat energy to the rock mass, particular attention is paid to heat transfer and thermal stress studies. 3 references, 31 figures, 3 tables

Handling and final disposal of nuclear waste. Hard Rock Laboratory

International Nuclear Information System (INIS)

1989-09-01

The purpose of the Hard Rock Laboratory is to provide an opportunity for research and development in a realistic and undisturbed underground rock environment down to the depth planned for the future repository. The R and D work in the underground laboratory has the following main goals: To test the quality and appropriateness of different methods for characterizing the bedrock with respect to conditions of importance for a final repository. To refine and demonstrate methods for how to adapt a repository to the local properties of the rock in connection with planning and construction. And, finally, to collect material and data of importance for the safety of the future repository and for confidence in the quality of the safety assessments 13 figs, 3 tabs

Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

2001-03-01

The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass.

Characterization on the Fracture system in jurassic granitic rocks: Kosung and Yusung areas

International Nuclear Information System (INIS)

Kim, Kyung Su; Bae, Dae Seok; Kim, Chun Soo; Park, Byung Yoon; Koh, Yong Kweon

2001-03-01

The safety of waste disposal can be achieved by a complete isolation of radioactive wastes from biosphere or by a retardation of nuclide migration to reach an acceptable dose level. For the deep geological disposal of high-level radioactive waste, the potential pathways of nuclide primarily depend on the spatial distribution characteristics of conductive fractures in rock mass. Major key issues in the quantification of fracture system for a disposal site are involved in classification criteria, hydraulic parameters, geometry, field investigation methods etc. This research aims to characterize the spatial distribution characteristics of regional lineaments and background fractures in eastern and western-type granite rock mass

Deformation Monitoring of Waste-Rock-Backfilled Mining Gob for Ground Control.

Science.gov (United States)

Zhao, Tongbin; Zhang, Yubao; Zhang, Zhenyu; Li, Zhanhai; Ma, Shuqi

2017-05-05

Backfill mining is an effective option to mitigate ground subsidence, especially for mining under surface infrastructure, such as buildings, dams, rivers and railways. To evaluate its performance, continual long-term field monitoring of the deformation of backfilled gob is important to satisfy strict public scrutiny. Based on industrial Ethernet, a real-time monitoring system was established to monitor the deformation of waste-rock-backfilled gob at -700 m depth in the Tangshan coal mine, Hebei Province, China. The designed deformation sensors, based on a resistance transducer mechanism, were placed vertically between the roof and floor. Stress sensors were installed above square steel plates that were anchored to the floor strata. Meanwhile, data cables were protected by steel tubes in case of damage. The developed system continually harvested field data for three months. The results show that industrial Ethernet technology can be reliably used for long-term data transmission in complicated underground mining conditions. The monitoring reveals that the roof subsidence of the backfilled gob area can be categorized into four phases. The bearing load of the backfill developed gradually and simultaneously with the deformation of the roof strata, and started to be almost invariable when the mining face passed 97 m.

Summary of United States Geological Survey investigations of fluid-rock-waste reactions in evaporite environments under repository conditions

International Nuclear Information System (INIS)

Stewart, D.B.; Jones, B.F.; Roedder, E.; Potter, R.W. II

1980-01-01

The interstitial and inclusion fluids contained in rock salt and anhydrite, though present in amounts less than 1 weight per cent, are chemically aggressive and may react with canisters or wastes. The three basic types of fluids are: (1) bitterns residual from saline mineral precipitation including later recrystallization reactions; (2) brines containing residual solutes from the formation of evaporite that have been extensively modified by reactions with contiguous carbonate of clastic rocks; and (3) re-solution brines resulting from secondary dehydration of evaporite minerals or solution of saline minerals by undersaturated infiltrating waters. Fluid composition can indicate that meteoric flow systems have contacted evaporites or that fluids from evaporites have migrated into other formations. The movement of fluids trapped in fluid inclusions in salt from southeast New Mexico is most sensitive to ambient temperature and to inclusion size, although several other factors such as thermal gradient and vapour/liquid ratio are also important. There is no evidence of a threshold temperature for movement of inclusions. Empirical data are given for determining the amount of brine reaching the heat source if the temperature, approximate amount of total dissolved solids, and Ca:Mg ratio in the brine are known. SrCl 2 and CsCl can reach high concentrations in saturated NaCl solutions and greatly depress the liquidus. The possibility that such fluids, if generated, could migrate from a high-level waste repository must be minimized because the fluid would contain its own radiogenic energy source in the first decades after repository closure, thus changing the thermal evolution of the repository from designed values. (author)

Corrosion testing of selected packaging materials for disposal of high-level waste glass in rock salt formations

International Nuclear Information System (INIS)

Smailos, E.; Schwarzkopf, W.; Koester, R.; Fiehn, B.; Halm, G.

1990-05-01

In previous corrosion studies performed in salt brines, unalloyed steels, Ti 99.8-Pd and Hastelloy C4 have proved to be the most promising materials for long-term resistant packagings to be used in heat-generating waste (vitrified HLW, spent fuel) disposal in rock-salt formations. To characterise the corrosion behaviour of these materials in more detail, further in-depth laboratory-scale and in-situ corrosion studies have been performed in the present study. Besides the above-mentioned materials, also some in-situ investigations of the iron-base materials Ni-Resist D2 and D4, cast iron and Si-cast iron have been carried out in order to complete the results available to date. (orig.) [de

Repository for high level radioactive wastes in Brazil: the importance of geochemical (Micro thermometric) studies and fluid migration in potential host rocks; Repositorios para rejeitos radioativos de alto nivel (RANR) no Brasil: a importancia de estudos geoquimicos (microtermometricos) e de migracao de fluidos em rochas potenciamente hospedeiras

Energy Technology Data Exchange (ETDEWEB)

Rios, Francisco Javier; Fuzikawa, Kazuo; Alves, James Vieira; Neves, Jose Marques Correia [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN-CNEN-MG), Belo Horizonte, MG (Brazil). Lab. de Inclusoes Fluidas e Metalogenese]. E-mail: javier@cdtn.br

2003-04-15

A detailed fluid inclusion study of host rocks, is of fundamental importance in the selection of geologically suitable areas for high level nuclear waste repository constructions (HLRW). The LIFM-CDTN is enabled to develop studies that confirm: the presence or not, of corrosive fluid in minerals from host rocks of the repository and the possible presence of micro fractures (and fluid leakage) when these rocks are submitted to high temperatures. These fluid geochemistry studies, with permeability determinations by means of pressurized air injection must be carried out in rocks hosting nuclear waste. Micro fracture determination is of vital importance since many naturally corrosive solutions, present in the mineral rocks, could flow out through these plans affecting the walls of the repository. (author)

Thermal-mechanical aspects for radioactive waste storage into underground caverns

International Nuclear Information System (INIS)

Vieira, Alvaro.

1985-12-01

The thermal and mechanical behaviors of rock mass by analytical models, considering transient effects of the heat generation from radioactive wastes, are analysed. The models were applied to Brazilian gneissic type of rock, considering the usual design of vitrified waste cylinders individually installed into conveniently spaced holes. (M.C.K.) [pt

Deformations of fractured rock

International Nuclear Information System (INIS)

Stephansson, O.

1977-09-01

Results of the DBM and FEM analysis in this study indicate that a suitable rock mass for repository of radioactive waste should be moderately jointed (about 1 joint/m 2 ) and surrounded by shear zones of the first order. This allowes for a gentle and flexible deformation under tectonic stresses and prevent the development of large cross-cutting failures in the repository area. (author)

SYNROC process. A geochemical approach to nuclear waste immobilization

Energy Technology Data Exchange (ETDEWEB)

Ringwood, A E; Kesson, S E; Ware, N G; Hibberson, W O; Major, A [Australian National Univ., Canberra. Research School of Earth Sciences

1979-08-01

The SYNROC process is proposed to immobilize high-level wastes as dilute solid solutions in the constituent minerals of a synthetic rock formed from a mixture of oxides. New modification of the SYNROC was developed. Experiments showed that the entire spectra of high-level waste elements can be incorporated in the crystal lattices of Ba-hollandite, perovskite and zirconolite. This titanate assemblage has been proved to be exceptionally resistant to hydrothermal leaching, and in this respect, amongst others, it is demonstrably superior to alternative ceramic waste forms and to borosilicate glasses. The relative stability of various waste forms was compared in hydrothermal leaching experiments using both pure water and 10 w/o NaCl solution. Borosilicate glasses were almost completely decomposed and disintegrated after only 24 hours at 350 deg C and 1000 bars, and the extensive loss of hazardous high-level waste elements occurred. The phase pollucite in ceramic waste forms began to decompose at 400 deg C. The hollandite-perovskite-zirconolite SYNROC assemblage was proved to be exceptionally resistant to leaching, surviving invariably the extreme conditions up to 900 deg C and 5000 bars. Geochemical studies of the naturally-occurring minerals containing radwaste elements are relevant to the problem of radiation damage to SYNROC phases. These imply that the 2-particle flux in SYNROC is unlikely to be enough to impair the ability to immobilize radwaste for the required period. The production of SYNROC is explained in detail. The SYNROC phases have the structures analogous to the natural minerals which have survived a variety of geological conditions for millions of years while retaining certain high-level waste elements in their crystal lattices.

Small-scale bentonite injection test on rock

International Nuclear Information System (INIS)

Pusch, R.

1978-03-01

When radiactive waste is disposed a sealing of the rock is very valuable since it reduces the rate of water percolation and diffusion. In an earlier report injection of bentonite gels by means of over-pressure and subsequent electrophoresis has been suggested. The present report describes a rock test series where bentonite injection was applied. For the test an approximately cubical block of about 1 m 3 was selected. The rock type was diorite with a fairly high frequency of quartz denses. The block was kept in a basin during the test in order to maintain the water saturation. Holes were bored in the block. A bentonite slurry with 1000 percent water content was injected. It was shown that the bentonite had a sealing effect but the depth of extrusion into rock joints was not large because of gelation. Electro-Kinetic injection of montmorillonite was found to be a more promising technique for rock lightening

Evaluation of Used Fuel Disposition in Clay-Bearing Rock

Energy Technology Data Exchange (ETDEWEB)

Jove-Colon, Carlos F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Weck, Philippe F. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hammond, Glenn Edward [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kuhlman, Kristopher L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, James [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Caporuscio, Florie Andre [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Cheshire, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Palaich, Sarah [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Norskog, Katherine E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zavarin, Mavrik [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wolery, Thomas J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jerden, James L. [Argonne National Lab. (ANL), Argonne, IL (United States); Copple, Jacqueline M. [Argonne National Lab. (ANL), Argonne, IL (United States); Cruse, Terry [Argonne National Lab. (ANL), Argonne, IL (United States); Ebert, William L. [Argonne National Lab. (ANL), Argonne, IL (United States)

2015-09-04

Deep geological disposal of nuclear waste in clay/shale/argillaceous rock formations has received much consideration given its desirable attributes such as isolation properties (low permeability), geochemically reduced conditions, slow diffusion, sorbtive mineralogy, and geologically widespread (Jové Colón et al., 2014). There is a wealth of gained scientific expertise on the behavior of clay/shale/ argillaceous rock given its focus in international nuclear waste repository programs that includes underground research laboratories (URLs) in Switzerland, France, Belgium, and Japan. Jové Colón et al. (2014) have described some of these investigative efforts in clay rock ranging from site characterization to research on the engineered barrier system (EBS). Evaluations of disposal options that include nuclear waste disposition in clay/shale/argillaceous rock have determined that this host media can accommodate a wide range of waste types. R&D work within the Used Fuel Disposition Campaign (UFDC) assessing thermal effects and fluid-mineral interactions for the disposition of heat-generating waste have so far demonstrated the feasibility for the EBS and clay host rock to withstand high thermal loads. This report represents the continuation of disposal R&D efforts on the advancement and refinement of coupled Thermal-Hydrological-Mechanical-Chemical (THMC), hydrothermal experiments on clay interactions, used fuel degradation (source term), and thermodynamic modeling and database development. The development and implementation of a clay/shale/argillite reference case described in Jové Colón et al. (2014) for FY15 will be documented in another report (Mariner et al. 2015) – only a brief description will be given here. This clay reference case implementation is the result of integration efforts between the GDSA PA and disposal in argillite work packages. The assessment of sacrificial zones in the EBS is being addressed through experimental work along with 1D reactive

Uso do residuo de beneficiamento de rochas ornamentais na producao de argamassa de multiplo uso; Use of the ornamental rock waste in mortar multiple-use

Energy Technology Data Exchange (ETDEWEB)

Faial, Alline Silveira Ribeiro; Xavier, Gustavo de Castro; Alexandre, Jonas; Maia, Paulo Cesar de Almeida; Albuquerque Junior, Fernando Saboya, E-mail: gxavier@uenf.br [Universidade Estadual do Norte Fluminense Darcy Ribeiro (UENF/LECIV), Campos dos Goytacazes, RJ (Brazil). Lab. de Engenharia Civil

2012-07-01

The municipal district of Itapemirim-ES is the largest producer of ornamental stones in Brazil. The processing of these rocks for the manufacture of floor and produces a large amount of waste approximately 15,000 tons/month, which still are responsible for damage to the environment. Aiming at the use of this waste, this paper studies experimentally the production of mortars of multiple use, making the replacement of the use of hydrated lime, widely used in the manufacture of mortars in construction, by the waste of the processing of a marble industry Itapemirim -ES. The mortar waste was characterized and evaluated by comparing performance with mortar with the addition of hydrated lime. We used a slurry with lime as a reference, ie the mixture was made of 1:1:8 (cement: waste / lime sand), where the workability and the properties of the hardened condition were evaluated and compared with the mortars made with the waste of marble. The compressive strength results showed that the waste with lime mortars were 1.6 ± 0.5 MPa and 1.4 MPa respectively ± 0.6 after 28 days of curing, two were classified as P1 (ABNT 13279, 2005), can replace the waste lime, thereby reducing the cost of manufacture of the mortar. (author)

Cosmogenic Nuclide Exposure Dating of the Tiltill Rock Avalanche, Yosemite National Park

Science.gov (United States)

Ford, K. R.; Pluhar, C. J.; Stone, J. O.; Stock, G. M.; Zimmerman, S. R.

2013-12-01

Yosemite National Park serves as an excellent natural laboratory for studying rock falls and rock avalanches because these are the main processes modifying the nearly vertical slopes of this recently glaciated landscape. Mass wasting represents a significant hazard in the region and the database of previous rock falls and other mass wasting events in Yosemite is extensive, dating back to the mid-1800s. However, this record is too short to capture the recurrence characteristics and triggering mechanisms of the very largest events, necessitating studies of the geologic record of mass wasting. Rock falls and rock avalanches are readily dated by cosmogenic nuclide methods due to their instantaneous formation, and results can be tied to triggering events such as seismic activity (e.g. Stock et al., 2009). Here, we apply exposure dating to the Holocene Tiltill rock avalanche north of Hetch Hetchy Reservoir. The deposit comprises what appear to be two separate lobes of rock and debris, yielding a total volume of ~3.1 x 106 m3. Assuming an erosion rate of 0.0006 cm/yr and neglecting snowpack shielding, preliminary data suggest a mean exposure age of 11,000 + 600 year B.P. for both deposits, indicating that they were emplaced in a single event. The age of the Tiltill 'slide' is similar to earthquakes on the Owens Valley Fault between 10,800 + 600 and 10,200 + 200 cal year B.P. (Bacon, 2007) and the White Mountain Fault, ~10,000 cal year B.P. (Reheis, 1996; DePolo, 1989). Given that movement on the Owens Valley fault in 1872 caused a number of rock falls in Yosemite and the coincidence of ages between the Tiltill 'slide' and paleoseismic events, a large earthquake in Eastern Sierra Nevada may have triggered this event. Other trigger events are also possibilities, but only through compilation of a database of large rock avalanches can statistically significant groupings of events begin to demonstrate whether seismic triggering is a dominant process.

Radioactive wastes storage and disposal. Chapter 8

International Nuclear Information System (INIS)

2002-01-01

The Chapter 8 is essentially dedicated to radioactive waste management - storage and disposal. The management safety is being provided due to packages and facilities of waste disposal and storage. It is noted that at selection of sites for waste disposal it is necessary account rock properties and ways of the wastes delivery pathways

MCCREEP - a model to estimate creep produced by microcracking around a cavity in an intact rock mass

International Nuclear Information System (INIS)

Wilkins, B.J.S.; Rigby, G.L.

1991-11-01

AECL Research is examining the disposal of nuclear fuel waste in a vault in plutonic rock. Models (MCDIRC and MCROC) have been developed to predict the mechanical behaviour of the rock in response to excavation and heat from the waste. The dominant mechanism of deformation at temperatures below 150 degrees C is microcracking, which results in rock creep and a decrease in rock strength. MCDIRC has been constructed to consider the perturbation of the stress state of intact rock by long cylindrical cavities. Slow crack-growth data are used to estimate time-dependent changes in rock strength, from which possible movements (creep strain) in the rock mass are estimated. MCDIRC depends on analytical solutions for stress-state perturbations. MCCREEP has been developed from MCDIRC and relies on the use of finite-element methods to solve for stress states. It is more flexible than MCDIRC and can deal with non-homogeneous rock properties and non-symmetrical cavities

Conceptual and safety-related questions in the final storage of radioactive waste - a comparison of various types of host rock

International Nuclear Information System (INIS)

Kleemann, U.

2005-01-01

The German Federal Office for Radiation Protection (BfS) in early November published the synthesis report (BfS 2005) about the conceptual and safety-related specific questions associated with the final storage of radioactive waste. In addition to a condensed version of twelve individual projects, the report contains a description of the results of the peer review and the workshops carried out, in particular an evaluation comparing different types of host rock in Germany. The whole project constitutes a comprehensive documentation of the current state of the art. Findings are expressed at a general level referring neither to the suitability of any specific repository site nor to that of salts as a repository formation, but covering all potential repository formations in deep geologic strata in Germany. The limits to and possibilities of, generic comparisons of various types of host rock are shown. It si seen that, in principle, none of the host rock varieties in Germany would be preferable to others. Numerous problems can be solved only for specific sites, thus requiring site comparisons. While some questions indicate a need for regulatory treatment, the need for basic research is considered to be low. The contribution presents the main findings made in each of the specific projects and the evaluations by the Office. (orig.)

Evaluation of leachate emissions from crushed rock and municipal solid waste incineration bottom ash used in road construction.

Science.gov (United States)

Lidelöw, S; Lagerkvist, A

2007-01-01

Three years of leachate emissions from municipal solid waste incineration bottom ash and crushed rock in a full-scale test road were evaluated. The impact of time, construction design, and climate on the emissions was studied, and the predicted release from standard leaching tests was compared with the measured release from the road. The main pollutants and their respective concentrations in leachate from the roadside slope were Al (12.8-85.3 mg l(-1)), Cr (2-125 microg l(-1)), and Cu (0.15-1.9 mg l(-1)) in ash leachate and Zn (1-780 microg l(-1)) in crushed rock leachate. From the ash, the initial Cl(-) release was high ( approximately 20 g l(-1)). After three years, the amount of Cu and Cl(-) was in the same range in both leachates, while that of Al and Cr still was more than one order of magnitude higher in ash leachate. Generally, the release was faster from material in the uncovered slopes than below the pavement. Whether the road was asphalted or not, however, had minor impacts on the leachate quality. During rain events, diluted leachates with respect to, e.g., salts were observed. The leaching tests failed to simulate field leaching from the crushed rock, whereas better agreement was observed for the ash. Comparisons of constituent release from bottom ash and conventional materials solely based on such tests should be avoided.

Leaching behaviour of copper slag, construction and demolition waste and crushed rock used in a full-scale road construction.

Science.gov (United States)

Lidelöw, Sofia; Mácsik, Josef; Carabante, Ivan; Kumpiene, Jurate

2017-12-15

The leaching behaviour of a road construction with fayalitic copper slag, recycled concrete and crushed rock as sub-base materials was monitored over ten years. All studied materials used in the road construction, including crushed rock, contained concentrations of several elements exceeding the guideline values recommended by the Swedish EPA for total element concentrations for waste materials used in constructions. Despite that, leaching from the road construction under field conditions in general was relatively low. The leachates from the recycled materials contained higher concentrations of several constituents than the leachates from the reference section with crushed rock. The leaching of the elements of interest (Cr, Mo, Ni, Zn) reached peak concentrations during the second and fourth (Cu) years and decreased over the observation period to levels below the Swedish recommended values. Carbonation of the concrete aggregates caused a substantial but short-term increase in the leaching of oxyanions such as chromate. The environmental risks related to element leaching are highest at the beginning of the road life. Ageing of materials or pre-treatment through leaching is needed prior to their use in construction to avoid peak concentrations. Also, the design of road constructions should be adjusted so that recycled materials are covered with low-permeability covers, which would minimize the exposure to atmospheric precipitation and weathering. Copyright © 2017 Elsevier Ltd. All rights reserved.

The disposal of Canada`s nuclear fuel waste: a study of postclosure safety of in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock volume 1: summary

Energy Technology Data Exchange (ETDEWEB)

Wikjord, A G; Baumgartner, P; Johnson, L H; Stanchell, F W; Zach, R; Goodwin, B W

1996-06-01

The concept for disposal of Canada`s nuclear fuel waste involves isolating the waste in corrosion-resistant containers emplaced and sealed within a vault at a depth of 500 to 1000 m in plutonic rock of the Canadian Shield. The case for the acceptability of the concept as a means of safely disposing of Canada`s nuclear fuel waste is presented in an Environmental Impact Statement (EIS) The disposal concept permits a choice of methods, materials, site locations and designs. The EIS presents a case study of the long-term (i.e., postclosure) performance of a hypothetical implementation of the concept, referred to in this report as the reference disposal system. The reference disposal system is based on borehole emplacement of used CANDU fuel in Grade-2 titanium alloy containers in low-permeability, sparsely fractured plutonic rock of the Canadian Shield. We evaluate the long-term performance of another hypothetical implementation of the concept based on in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock. The geological characteristics of the geosphere assumed for this study result in short groundwater travel times from the disposal vault to the surface. In the present study, the principal barrier to the movement of contaminants is the long-lasting copper container. We show that the long-lasting container can effectively compensate for a permeable host rock which results in an unfavourable groundwater flow condition. These studies illustrate the flexibility of AECL`s disposal concept to take advantage of the retention, delay, dispersion, dilution and radioactive decay of contaminants in a system of natural barriers provided by the geosphere and hydrosphere and of engineered barriers provided by the waste form, container, buffer, backfills, other vault seals and grouts. In an actual implementation, the engineered system would be designed for the geological conditions encountered at the host site. 34 refs., 2 tabs., 11 figs.

FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock

Energy Technology Data Exchange (ETDEWEB)

Alberid, J; Barcala, J M; Campos, R; Cuevas, A M; Fernandez, E [Ciemat. Madrid (Spain)

2000-07-01

FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

Radon as a natural tracer for gas transport within uranium waste rock piles

International Nuclear Information System (INIS)

Silva, N.C.; Chagas, E.G.L.; Dias, D.C.S.; Guerreiro, E.T.Z.; Alberti, H.L.C.; Braz, M.L.; Abreu, C.B.; Lopez, D.; Branco, O.; Fleming, P.

2014-01-01

Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Industrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222 Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222 Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m -3 with mean concentration of 320.7±263.3 kBq m -3 . (authors)

Thermal effects in disposal of radioactive waste in hard rock

International Nuclear Information System (INIS)

Bourke, P.J.; Hodgkinson, D.P.; Batchelor, A.S.

1978-01-01

The first objective of the UKAEA programme of field heating experiments is to study any variations in thermal conductivity of granite over long (10 - 100m) distances heated to high (100's 0 C) temperatures for about a year. A description is given of the first tests with an 18 kW heater at 50 m depth and 72 thermocouples in the surrounding 25m radius sphere of rock. The reasons for choice of this scale of experiment are presented and the problems encountered and initial results are described. The further objectives of these experiments are to investigate thermal stresses and any cracking of the granite so that thermally induced movement of water through rock with both its natural and any increased permeability can be quantified. Measurements to be made of the mechanical and permeable properties as the rock heats are described

Geosphere migration studies as support for the comparison of candidate sites for disposal of radioactive waste in rock-salt

International Nuclear Information System (INIS)

Glasbergen, P.; Hassanizadeh, S.M.; Noordijk, H.; Sauter, F.

1988-01-01

The Dutch research program on the geological disposal of radioactive waste was designed to supply a basis for the selection of combinations of three factors, i.e., type of rock-salt formation, site, and disposal technique, satisfying radiological standards and other criteria for final disposal. The potential sites have been grouped according to the type of rock-salt formation (e.g. bedded salt and salt domes) and two classes of depth below the surface of the ground. Values for geohydrological parameters were obtained by extrapolation of data from existing boreholes and analysis of the sedimentary environment. A three-dimensional model of groundwater flow and contaminant transport, called METROPOL, has been developed. To investigate the effect of high salinity on nuclide transport properly, a theoretical experimental study was carried out. Use of a thermodynamic approach showed that terms related to salt mass fraction have to be added to Darcy's and Fick's laws. An experimental study to investigate effects of these modifications is in progress. 8 refs.; 8 figs.; 1 table

A coupled reaction and transport model for assessing the injection, migration and fate of waste fluids

International Nuclear Information System (INIS)

Liu, X.; Ortoleva, P.

1996-01-01

The use of reaction-transport modeling for reservoir assessment and management in the context of deep well waste injection is evaluated. The study is based on CIRF.A (Chemical Interaction of Rock and Fluid), a fully coupled multiphase flow, contaminant transport, and fluid and mineral reaction model. Although SWIFT (Sandia Waste-Isolation Flow and Transport Model) is often the numerical model of choice, it can not account for chemical reactions involving rock, wastes, and formation fluids and their effects on contaminant transport, rock permeability and porosity, and the integrity of the reservoir and confining units. CIRF.A can simulate all these processes. Two field cases of waste injection were simulated by CIRF.A. Both observation data and simulation results show mineral precipitation in one case and rock dissolution in another case. Precipitation and dissolution change rock porosity and permeability, and hence the pattern of fluid migration. The model is shown to be invaluable in analyzing near borehole and reservoir-scale effects during waste injection and predicting the 10,000 year fate of the waste plume. The benefits of using underpressured compartments as waste repositories were also demonstrated by CIRF.A simulations

Artificial porous stone from of ornamental rock waste adaptable for civil construction and heritage restoration

International Nuclear Information System (INIS)

Durán Suárez, J.A.; García Casco, A.

2017-01-01

The technique of volumetric reintegration in severely deteriorated stone materials is of major importance for the restoration of architectural heritage. In using mortars for restoration it is important to control aspects such as the colour and textural similarity in relation to the adjacent stone, minor or equal strength and equal or greater porosity/permeability with respect to the original stone. This latter aspect is of particular complexity because the percentage distribution of pore-size ranges should not differ from that of the original stone material. The invention patent (with numbers of publication ES2187245 A1 and B1 16. 06. 2004), owned by the University of Granada, allows the production of excellent porous stones for decorative work in construction and mortar for restoration of stone materials with controlled porosity. Both materials consist of ornamental rock waste, so that a particular recycling purpose is given to this type of material which is difficult to reuse. In this paper we present the manufacturing process of these artificial stones and porous mortars with decorative and restorative purposes, from the controlled mixture of aggregates of ornamental rocks, organic and inorganic binders and generators of porosity. Once the curing and hardening has been done it is worth noting that one of the most important aspects of the product is the generation of a complex connected porous system as a result of the incorporation of crushed expanded polystyrene, which is activated after hardening through the application of organic solvents. [es

Survey on the characteristics of rock under low and high temperature

International Nuclear Information System (INIS)

Shin, Koich; Kitano, Koichi

1987-01-01

Rock caverns for Superconducting Magnetic Energy Storage (SMES), Radioactive Waste Disposal, or Liquified Natural Gas Storage will suffer extraordinary temperature. Therefore, authors have researched the rock characteristics under the low temperature conditions and the rock mass behavior when it is heated, by papers so far reported. As a result, rock characteristics such as strength, linear expansion coefficient, thermal conductivity etc. are found to be ready to change with temperature condition and the kind of rocks. Even an anisotropy of some kind appears under some conditions. So, when sitting those facilities before mentioned, rock characteristics under each temperature condition must be enough clarified for the purpose of the evaluation of rock cavern stability and especially, rock behavior when it is loaded dynamically under low temperature must be cleared from now on, for such studies have been few. (author)

Waste isolation safety assessment program. Collection and generation of transport data

International Nuclear Information System (INIS)

Apps, J.A.

1977-01-01

A project devoted to evaluation of mechanisms and rates of radioactive waste transport in igneous, metamorphic and sedimentary rocks is described. The research effort includes/ (1) calculation of the range of concentration expected for different radionuclides in given geologic environments by computer simulation of the groundwater chemistry; (2) development of a comprehensive theory relating exchange constants (K/sub D/s) to significant variables; (3) fabrication of test equipment to measure waste radionuclide transport rates in rock samples; (4) identification of transport rate controlling mechanisms; (5) experiments to determine K/sub D/ values for important radioactive waste elements for a variety of rock types and environmental conditions

An analytical one-dimensional model for predicting waste package performance

International Nuclear Information System (INIS)

Relyea, J.F.; Wood, M.I.

1984-01-01

A method for allocating waste package performance requirements among waste package components with regard to radionuclide isolation has been developed. Modification or change in this approach can be expected as the understanding of radionuclide behavior in the waste package improves. Thus, the performance requirements derived in this document are preliminary and subject to change. However, this kind of analysis is a useful starting point. It has also proved useful for identifying a small group of radionuclides which should be emphasized in a laboratory experimental program designed to characterize the behavior of specific radionuclides in the waste package environment. A simple one-dimensional, two media transport model has been derived and used to calculate radionuclide transport from the waste form-packing material interface of the waste package into the host rock. Cumulative release over 10,000 years, maximum yearly releases and release rates at the packing material-host rock interface were evaluated on a radionuclide-by radionuclide basis. The major parameters controlling radionuclide release were found to be: radionuclide solubility, porosity of the rock, isotopic ratio of the radionuclide and surface area of the waste form-packing material interface. 15 refs., 2 figs., 16 tabs

Radioactive waste isolation in salt: geochemistry of brine in rock salt in temperature gradients and gamma-radiation fields - a selective annotated bibliography

International Nuclear Information System (INIS)

Hull, A.B.; Williams, L.B.

1985-07-01

Evaluation of the extensive research concerning brine geochemistry and transport is critically important to successful exploitation of a salt formation for isolating high-level radioactive waste. This annotated bibliography has been compiled from documents considered to provide classic background material on the interactions between brine and rock salt, as well as the most important results from more recent research. Each summary elucidates the information or data most pertinent to situations encountered in siting, constructing, and operating a mined repository in salt for high-level radioactive waste. The research topics covered include the basic geology, depositional environment, mineralogy, and structure of evaporite and domal salts, as well as fluid inclusions, brine chemistry, thermal and gamma-radiation effects, radionuclide migration, and thermodynamic properties of salts and brines. 4 figs., 6 tabs

Radioactive waste isolation in salt: geochemistry of brine in rock salt in temperature gradients and gamma-radiation fields - a selective annotated bibliography

Energy Technology Data Exchange (ETDEWEB)

Hull, A.B.; Williams, L.B.

1985-07-01

Evaluation of the extensive research concerning brine geochemistry and transport is critically important to successful exploitation of a salt formation for isolating high-level radioactive waste. This annotated bibliography has been compiled from documents considered to provide classic background material on the interactions between brine and rock salt, as well as the most important results from more recent research. Each summary elucidates the information or data most pertinent to situations encountered in siting, constructing, and operating a mined repository in salt for high-level radioactive waste. The research topics covered include the basic geology, depositional environment, mineralogy, and structure of evaporite and domal salts, as well as fluid inclusions, brine chemistry, thermal and gamma-radiation effects, radionuclide migration, and thermodynamic properties of salts and brines. 4 figs., 6 tabs.

The disposal of Canada's nuclear fuel waste: a study of postclosure safety of in-room emplacement of used CANDU fuel in copper containers in permeable plutonic rock. Volume 3: geosphere model

International Nuclear Information System (INIS)

Stanchell, F.W.; Davison, C.C.; Melnyk, T.W.; Scheier, N.W.; Chan, T.

1996-06-01

This report discusses the approach we used to develop a model of the 3-D network of transport pathways through the geosphere from the location of a nuclear fuel waste disposal vault at a depth of 500 m in a hypothetical permeable plutonic rock mass. The transport pathways correspond to the pathways of advective groundwater movement through this permeable rock from the disposal vault to discharge areas at groundsurface. In this analysis we assumed the permeability of the region of rock immediately surrounding the waste emplacement areas of the disposal vault was considerably higher than the permeability used in the geosphere model for the EIS case study. We also assumed the porosity of the rock could fall within the range 10 -3 to 10 -5 to represent the range of effects by alternative conceptual models of flow through fracture networks in the rock. Advection by the groundwater flow field in the rock surrounding the disposal vault entirely controls the rate and direction of transport from the vault in this geosphere model. The hydrogeological environment we assumed for this geosphere model is entirely hypothetical, unlike the model we developed for the EIS case study which was a conservative, yet realistic, representation of the hydrogeological conditions encountered at the site of our Underground Research Laboratory in the Whiteshell Research Area. We used the same geometry of rock structures for this model as we used in the geosphere model for the EIS case study but we assigned hydrogeologic properties to the various rock domains of the model that result in relatively rapid groundwater flow from the depth of the disposal vault to surface discharge areas. This report desribes the modelling and sensitivity analyses we performed with the MOTIF finite element model to develop the GEONET transport network for this hypothetical geosphere situation. The geosphere model accounts for the effects of natural geothermal heat and vault-induced heat on transport pathways

Effect of channelling on water balance, oxygen diffusion and oxidation rate in mine waste rock with an inclined multilayer soil cover.

Science.gov (United States)

Song, Qing; Yanful, Ernest K

2010-05-20

Engineered soil covers provide an option to mitigate acid rock drainage through reduced water flow and gaseous oxygen influx to underlying mine waste. Channels such as fissures, cracks or fractures developed in the barrier may influence the long-term performance of the soil cover. However, limited published information is available on the extent to which soil cover performance is impacted by these fissures and cracks. This study was conducted to investigate the effect of channelling in a barrier layer on water flow and oxygen transport in a soil cover. Two inclined (a slope of 20%) multilayer soil covers were examined under laboratory conditions. One cover had a 10-cm wide sand-filled channel in a compacted barrier layer (silty clay) at the upslope section, while the other cover was a normal one without the channel pathway. The soil covers were installed in plastic boxes measuring 120 cm x 120 cm x 25 cm (width x height x thickness). The sand-filled channel was designed to represent the aggregate of fissures and cracks that may be present in the compacted barrier. The soil covers were subjected to controlled drying and wetting periods selected to simulate field situation at the Whistle mine site near Capreol, Ontario, Canada. The measured results indicated that interflow decreased from 72.8% of the total precipitation in the soil cover without channel flow to 35.3% in the cover with channel flow, and percolation increased from zero in the normal soil cover to 43.0% of the total precipitation in the cover with channel flow. Gaseous oxygen transfer into the waste rock below the cover soils was 1091 times greater in the cover with channel than in the soil cover without channel. The channel pathway present in the barrier layer acted as a major passage for water movement and gaseous oxygen diffusion into the waste rock layer, thus decreasing the performance of the soil cover. The spacing of the channel with respect to the length of the test box is similar to those found

Policy of radioactive waste disposal in the Netherlands

International Nuclear Information System (INIS)

Selling, H.A.

2002-01-01

Earlier this year the final report of the CORA Commission on retrievable disposal of radioactive waste was published. It confirmed the technical feasibility of retrievable repository concepts in the deep underground. Rock salt and sedimentary clay were considered as potential host rocks for such a repository. It is recommended, among other things, that subsequent research programmes should focus on stakeholder identification and involvement in a stepwise decision-making process of waste disposal. (author)

Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

International Nuclear Information System (INIS)

Zheng, Liange; Rutqvist, Jonny; Kim, Kunhwi; Houseworth, Jim

2015-01-01

The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

Investigation of Coupled Processes and Impact of High Temperature Limits in Argillite Rock

Energy Technology Data Exchange (ETDEWEB)

Zheng, Liange [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Rutqvist, Jonny [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kim, Kunhwi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Houseworth, Jim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2015-07-01

The focus of research within the UFD Campaign is on repository-induced interactions that may affect the key safety characteristics of an argillaceous rock. These include thermal-hydrological-mechanical-chemical (THMC) process interactions that occur as a result of repository construction and waste emplacement. Some of the key questions addressed in this report include the development of fracturing in the excavation damaged zone (EDZ) and THMC effects on the near-field argillaceous rock and buffer minerals and petrophysical characteristics, particularly the impacts of induced temperature rise caused by waste heat.

Composition of rock core from hole AEC-8, New Mexico

International Nuclear Information System (INIS)

Rhoderick, J.E.; Buck, A.D.

1981-12-01

AEC-8 is a borehole about 5000 ft deep located within the Waste Isolation Pilot Plant (WIPP) site in southeastern New Mexico. About 28 ft of rock core from seven depth intervals in this hole was characterized by petrographic examination. This included logging, examination of the rock with a stereomicroscope, examination of thin sections with a polarizing microscope, and examination of each sample by x-ray diffraction

Radiolysis salt phenomenology: application to storage of high level radioactive waste

International Nuclear Information System (INIS)

Akram, Najib

1993-01-01

In France, rock salt is a candidate repository for highly radioactive waste. Rock salt contains water and adsorbed gases which can be released in boreholes after heating due to vitrified wastes. In addition, waste-induced irradiation in near-field conditions induce radiolytic reactions which also contribute to gas release. The aim of this work is to understand and evaluate the effects of heat and irradiation produced by waste containers in a deep disposal, primarily concerning gas production. This is justified by the impact of gases on long-term safety: toxicity, explosibility, chemical reactivity, pressure build-up. We have evidenced the influence of integrated dose, filling gases, temperature and grain size on an homogeneous medium (Asse Mine rock salt). We have then studied heterogeneous samples, which allowed to determine the influence of the chemical and mineralogical composition of rock salt (bedded rock salt from the Mine de Potasse d'Alsace). The role played by organic matter on gas production is important, leading for instance to high consumption rates of oxygen. Through this study, we have also considered the behaviour of clay-rich materials under irradiation. Our results constitute important bases for the future modelling of the phenomena which will take place in the near-field of a rock salt-type repository, especially concerning its long-term safety. (author) [fr

Ground water movements around a repository. Rock mechanics analyses

International Nuclear Information System (INIS)

Ratigan, J.L.

1977-09-01

The determination and rational assessment of groundwater flow around a repository depends upon the accurate analysis of several interdependent and coupled phenomenological events occuring within the rock mass. In particular, the groundwater flow pathways (joints) are affected by the excavation and thermomechanical stresses developed within the rock mass, and the properties, of the groundwater are altered by the temperature perturbations in the rock mass. The objective of this report is to present the results of the rock mechanics analysis for the repository excavation and the thermally-induced loadings. Qualitative analysis of the significance of the rock mechanics results upon the groundwater flow is provided in this report whenever such an analysis can be performed. Non-linear rock mechanics calculations have been completed for the repository storage tunnels and the global repository domain. The rock mass has been assumed to possess orthoganol joint sets or planes of weakness with finite strength characteristics. In the local analyses of the repository storage tunnels the effects of jointorientation and repository ventilation have been examined. The local analyses indicated that storage room support requirements and regions of strength failure are highly dependent upon joint orientation. The addition of storage tunnel ventilation was noted to reduce regions of strength failure, particularly during the 30 year operational phase of the repository. Examination of the local stresses around the storage tunnels indicated the potential for perturbed hydraulic permeabilities. The permeabilities can be expected to be altered to a greater degree by the stresses resulting from excavation than from stresses which are thermally induced. The thermal loading provided by the instantaneous waste emplacement resulted in stress states and displacements quite similar to those provided by the linear waste emplacement sequence

Waste-isolation projects, FY 1978

International Nuclear Information System (INIS)

Ramspott, L.D.

1979-01-01

This report describes Lawrence Livermore Laboratory (LLL) activities during FY 1978 in support of the National Waste Terminal Storage Program. Current projects at LLL fall into three categories: (1) field testing, (2) laboratory rock mechanics measurements, and (3) laboratory studies of sorption and leaching. Field test activities conducted in the Climax granite at the Nevada Test Site included electrical heater tests, preparation for a spent-fuel-storage test, and planning for a series of rock mechanics tests. The heater tests determined the in situ thermal properties of Climax granite and its in situ permeability as a function of rock temperature. The two main laboratory rock mechanics projects involved (1) measurement of the permeability, electrical conductivity, and acoustic velocity of 15-cm-diam cores of granitic rocks over a range of confining pressure, pore (water) pressure, and deviatoric stress, and (2) measurement of rock thermal properties as a function of temperature and confining pressure in the presence of pore fluids to 770 0 K and 200 Mpa. The leaching studies made use of an LLL-designed, single-pass leaching apparatus with three solutions, two leach temperatures, and three flow rates. The material evaluated was Np--Pu-doped simulated waste glass from Battelle Pacific Northwest Laboratories. The sorption studies involved standard static measurements of the equilibrium distribution coefficient (K/sub d/) for various radionuclides on a variety of rocks, and flow-through-core studies of dynamic sorption

Self-healing of excavation-disturbed rocks in the near field of underground cavities - exemplary measurements in rock salt and interpretation of preliminary results

International Nuclear Information System (INIS)

Wieczorek, K.; Schwarzianeck, P.; Rothfuchs, T.

2001-01-01

Excavation disturbed zones develop in all kinds of rock as a consequence of the opening of cavities. Such zones are characterized by a change in hydraulic behaviour which can form a problem with regard to the sealing of waste disposal areas. Rocks showing a plastic behaviour, like rock salt, have the potential of healing when the stress state which was disturbed by excavation returns to an advantageous state. If healing can reliably be predicted, the excavation disturbed zone may not form a long-term safety issue in rock salt. Investigations of permeability and stress state around lined and open excavations have been performed in order to relate hydraulic behaviour to stress state. First results which are presented here are promising. (authors)

Final environmental impact statement. Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

1980-10-01

This volume contains the appendices for the Final Environmental Impact Statement for the Waste Isolation Pilot Plant (WIPP). Alternative geologic environs are considered. Salt, crystalline rock, argillaceous rock, and tuff are discussed. Studies on alternate geologic regions for the siting of WIPP are reviewed. President Carter's message to Congress on the management of radioactive wastes and the findings and recommendations of the interagency review group on nuclear waste management are included. Selection criteria for the WIPP site including geologic, hydrologic, tectonic, physicochemical compatability, and socio-economic factors are presented. A description of the waste types and the waste processing procedures are given. Methods used to calculate radiation doses from radionuclide releases during operation are presented. A complete description of the Los Medanos site, including archaeological and historic aspects is included. Environmental monitoring programs and long-term safety analysis program are described

Radiation effects in rock salt. A status report

International Nuclear Information System (INIS)

Gies, H.; Hild, W.; Kuehle, T.; Moenig, J.

1994-01-01

Knowledge of the irradiation defects and the accompanying energy storage in rock salt resulting from the absorption of ionizing radiation emitted by vitrified high level radioactive waste (HLW) disposed off in geological rock salt formations in an important prerequisite for a realistic assessment of possible consequences. Based on a critical review of the scientific status this report attempts to evaluate whether the available database is satisfactory and sufficiently reliable for the performance of such an assessment. Apart from a brief description of the radiation-and temperature-conditions prevailing in a HLW-repository, a detailed presentation is given of both the interaction of radiation with rock salt and the theories and models developed for their quantification

Thermal conductivity of the rocks in the Bureau of Mines Standard Rock Suite

International Nuclear Information System (INIS)

Morgan, M.T.; West, G.A.

1980-01-01

Thermal conductivities of eight rocks from the Bureau of Mines Standard Rock Suite were measured in air over the temperature range 373 to 533 0 K (100 to 260 0 C). The thermal conductivities of these rocks were measured to furnish standards for future comparisons with host rock from prospective nuclear waste repository sites. The thermal conductivity at a given temperature decreased by as much as 9% after a specimen had been heated to the maximum temperature (533 0 K), but additional heating cycles had no further effect. This decrease was smallest in the igneous rocks and largest in the sedimentary types. Variations due to orientation were within the precision of measurements (+- 5%). In most cases the thermal conductivities were linear with the reciprocal of the temperature and were within 14% of published data obtained by other methods. Measurements were made by a cut-bar comparison method in which the sample was sandwiched between two reference or metering bars made of Pyroceram 9606 glass-ceramic. The apparatus consisted of a Dynatech Model TCFCM-N20 comparative thermal conductivity analyzer controlled by a Hewlett Packard Model 3052A data acquisition system. A program was written to increment and cycle the temperature in steps between predetermined initial and maximum values. At each step the thermal conductivity was measured after steady-state conditions were established. The rocks furnished by the Bureau of Mines were quarried in large and fairly homogeneous lots for use by researchers at various laboratories. To investigate any anisotropy, cores were taken from each rock cube perpendicular to each of the cube faces. Samples 2 in. in diameter and approx. 0.75 in. thick were prepared from the cores and were dried in a vacuum oven for at least one month prior to taking measurements

Nuclear waste management. Quarterly progress report, January-March 1980

Energy Technology Data Exchange (ETDEWEB)

Platt, A.M.; Powell, J.A. (comps.)

1980-06-01

Reported are: high-level waste immobilization, alternative waste forms, nuclear waste materials characterization, TRU waste immobilization, TRU waste decontamination, krypton solidification, thermal outgassing, iodine-129 fixation, unsaturated zone transport, well-logging instrumentation development, mobile organic complexes of fission products, waste management system and safety studies, assessment of effectiveness of geologic isolation systems, waste/rock interactions, engineered barriers, criteria for defining waste isolation, and spent fuel and pool component integrity. (DLC)

Deep underground disposal of radioactive wastes: Near field effects

International Nuclear Information System (INIS)

1985-01-01

This report reviews the important near-field effects of the disposal of wastes in deep rock formations. The basic characteristics of waste form, container and package, buffer and backfill materials and potential host-rock types are discussed from the perspective of the performance requirements of the total repository system. Effects of waste emplacement on the separate system components and on the system as a whole are discussed. The effects include interactions between groundwater and brines and the other system components, thermal and thermo-mechanical effects, and chemical and geochemical reactions. Special consideration is given to the radiation field that exists in proximity to the waste containers and also to the coupled effects of different phenomena

The modelling and measurement of super-conducting rock joints

International Nuclear Information System (INIS)

Barton, N.; Makurat, A.; Vik, G.; Loset, F.

1985-01-01

Rock joints exhibiting exceptionally high conductivity have been responsible for severe inflows (10-50 m 3 /min.) and flooding in recent Norwegian tunneling projects. These events may be explained by channeling of flow in partially outwashed mineral fillings, associated with deep weathering in ancient basement rocks. There is also evidence to suggest extensional strain with consistent relationships to regional faulting patterns (Selmer-Olsen 1981). Hydraulic fractures making connection with joint systems that are sheared as a result of increased fluid pressure, has been deduced as the mechanism explaining unusually large fluid losses in the geothermal project in Cornwall, England (Pine and Batchelor, 1984). Such mechanisms also introduce uncertainty into water flood and MHF stimulation treatment of fractured oil and gas reservoirs, particularly when principal stress and joint orientations are poorly understood due to coring and stress measurement problems in weak, overstressed reservoir rocks. The possibility of permanent disposal of nuclear waste in crystalline rock, has also focussed attention on highly conductive (''super-conducting'') joints in nuclear waste programmes in Canada, the USA and in Europe. The bi-modal distributions of joint spacing, continuity, apertures and conductivities resulting from the discovery of super-conducting joints has important implications for the location of planned repositories, due to their dramatic impact on potential transport times. In the laboratory a class of super-conducting joints can be created by shear displacement that causes dilation when shearing non-planar features. Recent biaxial shear testing of rock joints recovered in jointed core has identified a strong coupling of conductivity and shear displacement. The theoretical predictions of constitutive relationships for coupled flow in rock joints (Barton et al. 1985) have been broadly verified

Sponsored research on radioactive waste management

International Nuclear Information System (INIS)

1983-01-01

The report is in chapters entitled: introduction (background, responsibilities, options, structure of the programme); strategy development; disposal of accumulations; disposal of radioactive waste arisings; quality assurance for waste conditioning quality assurance related to radioactive waste disposal (effectiveness of different rock types as natural barriers to the movement of radioactivity, and non-site specific factors in the design of repositories; radiological assessment; environmental studies; research and development to meet requirements specific to UKAEA wastes; long term research (processes for the solidification of highly active liquid wastes); plutonium contamination waste minimisation. (U.K.)

Nuclear waste disposal: technology and environmental hazards

International Nuclear Information System (INIS)

Hare, F.K.; Aikin, A.M.

1980-01-01

The subject is discussed under the headings: introduction; the nature and origin of wastes (fuel cycles; character of wastes; mining and milling operations; middle stages; irradiated fuel; reprocessing (waste generation); reactor wastes); disposal techniques and disposal of reprocessing wastes; siting of repositories; potential environmental impacts (impacts after emplacement in a rock repository; catastrophic effects; dispersion processes (by migrating ground water); thermal effects; future security; environmental survey, monitoring and modelling); conclusion. (U.K.)

Migration of particulates in permeable rock columns

International Nuclear Information System (INIS)

Cropper, R.L.

1982-01-01

The migration of radioactive material through soil and permeable rock formations have become a major topic of concern due to the interest in the licensing of new radioactive waste disposal sites. Previously, research has been conducted in relation to deep repositories; however, similar situations arise in the vadose zone, where there is a higher probability of naturally-occurring particulates of organic nature and for the incursion of water. Test data has provided information which suggests that particulates will travel through porous media subject to various delay mechnisms and must be included in any consideration of waste migration. Data concerning particulate migration must and should be considered in the future when radioactive waste disposal sites are licensed

Geo-scientific considerations on evaluation of possible sites for radioactive waste isolation in Japan

Energy Technology Data Exchange (ETDEWEB)

Doi, K [Radioactive Waste Management Center, Tokyo (Japan)

1980-08-01

Japan is located on the Circum-Pacific Arc, which is a geoscientifically difficult area for selecting sites suitable as repositories for isolating radioactive waste. The writer has analyzed the problems relevant to radioactive waste isolation in this aqueous and active structural territory, with a view to examining the possibility of finding geological formations suitable for such repositories. As a result, certain parts in Neogene sedimentary rocks and Palaeozoic calcarious rocks were found to present geological characteristics that appeared favorable for radioactive waste isolation, while, on the other hand, the study indicated that much difficulty would be foreseen in crystalline rocks such as are currently suitable in the US and in Europe for high level radioactive waste isolation.

In situ investigations on the impact of heat production and gamma radiation with regard to high-level radioactive waste disposal in rock salt formations

International Nuclear Information System (INIS)

Rothfuchs, T.

1986-01-01

Deep geological formations especially rock salt formations, are considered worldwide as suitable media for the final disposal of radioactive high-level waste (HLW). In the Federal Republic of Germany, the Institut fur Tieflagerung of the Gesellschaft fur Strahlen- und Umweltforschung mbH Munchen operates the Asse Salt Mine as a pilot facility for testing the behavior of an underground nuclear waste repository. The tests are performed using heat and radiation sources to simulate disposed HLW canisters. The measured data obtained since 1965 show that the thermomechanical response of the salt formation and the physical/chemical changes in the vicinity of disposal boreholes are not a serious concern and that their long-term consequences can be estimated based on theoretical considerations and in-situ investigations

Review of Studies of Clay Minerals as Significant Component of Potential Host Rocks or Engineering Barriers for Radioactive Waste Disposals Performed at Comenius University in Bratislava

International Nuclear Information System (INIS)

Peter, Uhlik; Vladimir, Sucha; Maria, Caplovicova; Igor, Stricek

2013-01-01

About 50 % of electric power is produced by nuclear power plants in Slovakia. In spite of the significant production of nuclear waste, Slovakia has not defined basic strategy of radioactive-waste isolation. However, some pilot projects and studies have been carried out. Five areas were determined as prospective sites for construction of deep geological repository (DGR). Two of them are situated in the south of Slovakia. Szecseny schlier (mixture of siltstones and Clay-stones) of Lucenec Formation (Egerian) is one of the most prospective host rocks from lithological, structural and spatial perspective. Besides the investigation of potential host rock for DGR the studies of bentonite properties as important part of engineering barriers for radioactive waste disposals were performed. Detailed mineral and structural analyses of smectites from the bentonitic material exposed to laboratory Mock-Up test were realised. Particular interest has been focused on interaction between Fe and smectites. Other field of interest is investigation of sorption of Cs and Sr on natural and modified bentonites, including irradiation. Purpose of this work is to present a short review of other studies done by our group with partial focusing to interaction of organic dye (Rhoda-mine 6G) with smectite that is connected with changes of layer charge after treatment; possibilities to measure preferential orientation of clays after compaction by TEM and to effort to use X-ray micro-tomography for inner structure of sediments. (authors)

Geologic factors in nuclear waste disposal

International Nuclear Information System (INIS)

Towse, D.

1978-07-01

The study of geosciences and their relation to nuclear waste disposal and management entails analyzing the hydrology, chemistry, and geometry of the nuclear waste migration process. Hydrologic effects are determined by analyzing the porosity and permeability (natural and induced) of rock as well as pressures and gradients, dispersion, and aquifer length of the system. Chemistry parameters include radionuclide retardation factors and waste dissolution rate. Geometric parameters (i.e., parameters with dimension) evaluated include repository layer thickness, fracture zone area, tunnel length, and aquifer length. The above parameters act as natural barriers or controls to nuclear waste migration, and are evaluated in three potential geologic media: salt, shale, and crystalline rock deposits. Parametric values are assigned that correspond to many existing situations. These values, in addition to other important inputs, are lumped as a hydrology input into a computer simulation program used to model and calculate nuclear waste migration from the repository to the biosphere, and potential individual and population dose and radiation effects. These results are preliminary and show trends only; they do not represent an actual risk analysis

Workshop on rock mechanics issues in repository design and performance assessment

International Nuclear Information System (INIS)

1996-04-01

The Center for Nuclear Waste Regulatory Analyses organized and hosted a workshop on ''Rock Mechanics Issues in Repository Design and Performance Assessment'' on behalf its sponsor the U.S. Nuclear Regulatory Commission (NRC). This workshop was held on September 19- 20, 1994 at the Holiday Inn Crowne Plaza, Rockville, Maryland. The objectives of the workshop were to stimulate exchange of technical information among parties actively investigating rock mechanics issues relevant to the proposed high-level waste repository at Yucca Mountain and identify/confirm rock mechanics issues important to repository design and performance assessment The workshop contained three technical sessions and two panel discussions. The participants included technical and research staffs representing the NRC and the Department of Energy and their contractors, as well as researchers from the academic, commercial, and international technical communities. These proceedings include most of the technical papers presented in the technical sessions and the transcripts for the two panel discussions

In situ measurement of the thermal conductivity in propylite rock mass

International Nuclear Information System (INIS)

Shimooka, Kenji; Araki, Kunio; Suda, Shintaro.

1982-11-01

The safety evaluation for the geological disposal of the high level waste becomes an urgent problem to establish the backend of nuclear fuel cycle. The stability of the original host rock and the flow of groundwater will be perturbed by the thermal disturbances from the waste. So the heater experiment at a depth of 90 m below the surface was carried out to study the conduction of decay heat. For measuring the thermal conductivity of propylite rock mass, a cylindrical heater and 13 thermocouples were inserted in 6 boreholes. The power output of the heater was kept at 880 W constant during the experimental periods of 61 days. From the observed temperature rise around the heater, the thermal conductivity 2.1 W/m 0 C was calculated by steady-state calculation. The value of the rock mass was found to be slightly bigger compared with 1.5 - 1.6 W/m 0 C of core samples. (author)

Initial waste package interaction tests: status report

International Nuclear Information System (INIS)

Shade, J.W.; Bradley, D.J.

1980-12-01

This report describes the results of some initial investigations of the effects of rock media on the release of simulated fission products from a sngle waste form, PNL reference glass 76-68. All tests assemblies contained a minicanister prepared by pouring molten, U-doped 76-68 glass into a 2-cm-dia stanless steel tube closed at one end. The tubes were cut to 2.5 to 7.5 cm in length to expose a flat glass surface rimmed by the canister wall. A cylindrical, whole rock pellet, cut from one of the rock materials used, was placed on the glass surface then both the canister and rock pellet were packed in the same type of rock media ground to about 75 μm to complete the package. Rock materials used were a quartz monzonite basalt and bedded salt. These packages were run from 4 to 6 weeks in either 125 ml digestion bombs or 850 ml autoclaves capable of direct solution sampling, at either 250 or 150 0 C. Digestion bomb pressures were the vapor pressure of water, 600 psig at 250 0 C, and the autoclaves were pressurized at 2000 psig with an argon overpressure. In general, the solution chemistry of these initial package tests suggests that the rock media is the dominant controlling factor and that rock-water interaction may be similar to that observed in some geothermal areas. In no case was uranium observed in solution above 15 ppB. The observed leach rates of U glass not in contact with potential sinks (rock surfaces and alteration products) have been observed to be considerably higher. Thus the use of leach rates and U concentrations observed from binary leach experiments (waste-form water only) to ascertain long-term environmental consequences appear to be quite conservative compared to actual U release in the waste package experiments. Further evaluation, however, of fission product transport behavior and the role of alteration phases as fission product sinks is required

Distribution coefficient of radionuclides on rocks for performance assessment of high-level radioactive waste repository

International Nuclear Information System (INIS)

Shibutani, Tomoki; Shibata, Masahiro; Suyama, Tadahiro

1999-11-01

Distribution coefficients of radionuclides on rocks are selected for safety assessment in the 'Second Progress Report on Research and Development for the geological disposal of HLW in Japan (H12 Report)'. The categorized types of rock are granitic rocks (crystalline and acidic rocks), basaltic rocks (crystalline and basic rocks), psammitic rocks (neogene sedimentary (soft)), and tuffaceous-pelitic rocks (pre-neogene sedimentary rocks (hard)). The types of groundwater are FRHP (fresh reducing high-pH), FRLP (fresh reducing low-pH), SRHP (saline reducing high-pH), SRLP (saline reducing low-pH), MRNP (mixing reducing neutral-pH) and FOHP (fresh oxidizing high-pH) groundwater. The elements to be surveyed are Ni, Se, Zr, Nb, Tc, Pd, Sn, Cs, Sm, Pb, Ra, Ac, Th, Pa, U, Np, Pu, Am and Cm. Distribution coefficients are collected from literatures describing batch sorption experimental results, and are selected under consideration of conservativity. (author)

Safety evaluation of geological disposal concepts for low and medium-level wastes in rock-salt (Pacoma project)

International Nuclear Information System (INIS)

Prij, J.; Van Dalen, A.; Roodbergen, H.A.; Slagter, W.; Van Weers, A.W.; Zanstra, D.A.; Glasbergen, P.; Koester, H.W.; Lembrechts, J.F.; Nijhof-Pan, I.; Slot, A.F.M.

1991-01-01

In the framework of the Performance Assessment of Confinements for MLW and Alpha Waste (PACOMA) the disposal options dealing with rock-salt are studied by GSF and ECN (with subcontract to RIVM). The overall objectives of these studies are to develop and demonstrate procedures for the radiological safety assessment of a deep repository in salt formations. An essential objective is to show how far appropriate choices of the repository design parameters can improve the performances of the whole system. The research covers two waste inventories (the Dutch OPLA and the PACOMA reference inventory), two disposal techniques (conventional and solution mining) and three types of formations (salt dome, pillow and bedded salt). An important part of the research has been carried out in the socalled VEOS project within the framework of the Dutch OPLA study. The methodology used in the consequence analysis is a deterministic one. The models and calculation tools used to perform the consequence analysis are the codes: EMOS, METROPOL and BIOS. The results are expressed in terms of dose rates and doses to individuals as well as to groups. Detailed information with respect to the input data and the results obtained with the three codes is given in three annexes to this final report

Development of rock segment for reduction of amount of cement use

International Nuclear Information System (INIS)

Tada, Hiroyuki; Kumasaka, Hiroo; Saito, Akira; Nakaya, Atsushi; Ishii, Takashi; Sanada, Masanori; Noguchi, Akira; Kishi, Hirokazu; Nakama, Shigeo; Fujita, Tomoo

2013-01-01

The authors have been developing methods for constructing tunnels using the minimum quantities of cement-type support materials in high-level radioactive waste disposal facilities and advancing research and development about the technical formation of rock segment using low alkali mortar. In this study, the mechanical characteristic values concerning the rock segment and backfill materials were examined. The stability analysis of drift supported by the rock segment and backfilling with gravel were performed. Technical formation and effectiveness of the support planned for further reduction in cement influence was confirmed from the study result. (author)

Final environmental impact statement. Waste Isolation Pilot Plant

Energy Technology Data Exchange (ETDEWEB)

1980-10-01

This volume contains the appendices for the Final Environmental Impact Statement for the Waste Isolation Pilot Plant (WIPP). Alternative geologic environs are considered. Salt, crystalline rock, argillaceous rock, and tuff are discussed. Studies on alternate geologic regions for the siting of WIPP are reviewed. President Carter's message to Congress on the management of radioactive wastes and the findings and recommendations of the interagency review group on nuclear waste management are included. Selection criteria for the WIPP site including geologic, hydrologic, tectonic, physicochemical compatability, and socio-economic factors are presented. A description of the waste types and the waste processing procedures are given. Methods used to calculate radiation doses from radionuclide releases during operation are presented. A complete description of the Los Medanos site, including archaeological and historic aspects is included. Environmental monitoring programs and long-term safety analysis program are described. (DMC)

Novel Microbial Assemblages Dominate Weathered Sulfide-Bearing Rock from Copper-Nickel Deposits in the Duluth Complex, Minnesota, USA.

Science.gov (United States)

Jones, Daniel S; Lapakko, Kim A; Wenz, Zachary J; Olson, Michael C; Roepke, Elizabeth W; Sadowsky, Michael J; Novak, Paige J; Bailey, Jake V

2017-08-15

The Duluth Complex in northeastern Minnesota hosts economically significant deposits of copper, nickel, and platinum group elements (PGEs). The primary sulfide mineralogy of these deposits includes the minerals pyrrhotite, chalcopyrite, pentlandite, and cubanite, and weathering experiments show that most sulfide-bearing rock from the Duluth Complex generates moderately acidic leachate (pH 4 to 6). Microorganisms are important catalysts for metal sulfide oxidation and could influence the quality of water from mines in the Duluth Complex. Nevertheless, compared with that of extremely acidic environments, much less is known about the microbial ecology of moderately acidic sulfide-bearing mine waste, and so existing information may have little relevance to those microorganisms catalyzing oxidation reactions in the Duluth Complex. Here, we characterized the microbial communities in decade-long weathering experiments (kinetic tests) conducted on crushed rock and tailings from the Duluth Complex. Analyses of 16S rRNA genes and transcripts showed that differences among microbial communities correspond to pH, rock type, and experimental treatment. Moreover, microbial communities from the weathered Duluth Complex rock were dominated by taxa that are not typically associated with acidic mine waste. The most abundant operational taxonomic units (OTUs) were from the genera Meiothermus and Sulfuriferula , as well as from diverse clades of uncultivated Chloroflexi , Acidobacteria , and Betaproteobacteria Specific taxa, including putative sulfur-oxidizing Sulfuriferula spp., appeared to be primarily associated with Duluth Complex rock, but not pyrite-bearing rocks subjected to the same experimental treatment. We discuss the implications of these results for the microbial ecology of moderately acidic mine waste with low sulfide content, as well as for kinetic testing of mine waste. IMPORTANCE Economic sulfide mineral deposits in the Duluth Complex may represent the largest

Problems of the final storage of radioactive waste in salt formations

International Nuclear Information System (INIS)

Hofrichter, E.

1977-01-01

The geological conditions for the final storage of radioactive waste, the occurrence of salt formations, and the tectonics of salt domes are discussed. The safety of salt rocks, the impermeability of the rocks, and the thermal problems in the storage of high-activity waste are dealt with. Possibilities and preconditions of final storage in West Germany are discussed. (HPH) [de

Stability of disposal rooms during waste retrieval

International Nuclear Information System (INIS)

Brandshaug, T.

1989-03-01

This report presents the results of a numerical analysis to determine the stability of waste disposal rooms for vertical and horizontal emplacement during the period of waste retrieval. It is assumed that waste retrieval starts 50 years after the initial emplacement of the waste, and that access to and retrieval of the waste containers take place through the disposal rooms. It is further assumed that the disposal rooms are not back-filled. Convective cooling of the disposal rooms in preparation for waste retrieval is included in the analysis. Conditions and parameters used were taken from the Nevada Nuclear Waste Storage Investigation (NNWSI) Project Site Characterization Plan Conceptual Design Report (MacDougall et al., 1987). Thermal results are presented which illustrate the heat transfer response of the rock adjacent to the disposal rooms. Mechanical results are presented which illustrate the predicted distribution of stress, joint slip, and room deformations for the period of time investigated. Under the assumption that the host rock can be classified as ''fair to good'' using the Geomechanics Classification System (Bieniawski, 1974), only light ground support would appear to be necessary for the disposal rooms to remain stable. 23 refs., 28 figs., 2 tabs

Numerical modeling of heat outflux from a vitrified high level waste

International Nuclear Information System (INIS)

Aravind, Arun; Jayaraj, Aparna; Seshadri, H.; Balasubramaniyan, V.

2018-01-01

Heat generating vitrified high-level waste is initially stored in interim storage facility with adequate cooling for sufficient period of time, and then proposed to be disposed of in deep geological repositories. Heat flux from the waste form can cause thermo mechanical changes within the disposal module and also in the surrounding rock. It may change the permeability of rock fractures over a period of time. It is very essential to study the long term performance of deep geological repository to build confidence in the design and over all operation of the disposal facility. In this study a numerical model was developed to study the temperature distribution in the waste matrix and also the heat out flux to the surrounding rock matrix

Mechanisms and modelling of waste-cement and cement-host rock interactions

Science.gov (United States)

2017-06-01

Safe and sustainable disposal of hazardous and radioactive waste is a major concern in today's industrial societies. The hazardous waste forms originate from residues of thermal treatment of waste, fossil fuel combustion and ferrous/non-ferrous metal smelting being the most important ones in terms of waste production. Low- and intermediate-level radioactive waste is produced in the course of nuclear applications in research and energy production. For both waste forms encapsulation in alkaline, cement-based matrices is considered to ensure long-term safe disposal. Cementitious materials are in routine use as industrial materials and have mainly been studied with respect to their evolution over a typical service life of several decades. Use of these materials in waste management applications, however, requires assessments of their performance over much longer time periods on the order of thousands to several ten thousands of years.

Microbiologically mediated processes in a repository sited in a clay host rock

International Nuclear Information System (INIS)

Schwyn, B.; Leupin, O. X.; Bagnoud, A.; Bernier-Latmani, R.

2012-01-01

Document available in extended abstract form only. Because of their favourable retention properties for radionuclides, clay-rich sediments are being considered in Switzerland as host rocks for the geological disposal of high, intermediate- and low-level radioactive waste. Compacted bentonite is foreseen as backfill material in the high level waste repository whereas for intermediate- and low-level waste the near field will mainly consist of cementitious material. The evolution of both types of repositories, which includes re-saturation, heat generation (only high level waste), near field degradation, gas production and radionuclide release may be impacted by microbial activity and vice versa. In this respect questions arise such as: - Are microorganisms present in a repository and its host rock? - Under which condition are microorganisms active in and around a repository? - In which processes are microorganisms involved? Various in situ experiments in a wide range of geological environments have evidenced the presence of microorganisms. Whether the microorganisms found in these in situ experiments are indigenous or introduced by drilling or/and excavation activities is still controversial. However, recent findings suggest the presence of indigenous microorganisms in Opalinus Clay. To conclusively answer the question about the origin of microorganisms, an international investigation programme has been launched to probe rock samples from the Underground Rock Laboratory at Mont Terri. So far, no metabolic activity has been observed in undisturbed clay rocks. Such activity may have ceased during diagenetic compaction of the sediment as suggested by the pore water composition measured in the Callovian-Oxfordian clayey formation of Bure (France). For the safety case of a repository the origin of microorganisms is of minor importance compared to the understanding of the conditions under which they might be metabolically active. Pore size distribution and connectivity can

FEBEX project: full-scale engineered barriers experiment for a deep geological repository for high level radioactive waste in crystalline host rock. Final report

International Nuclear Information System (INIS)

Alberdi, J.; Barcala, J. M.; Campos, R.; Cuevas, A. M.; Fernandez, E.

2000-01-01

FEBEX has the multiple objective of demonstrating the feasibility of manufacturing, handling and constructing the engineered barriers and of developing codes for the thermo-hydro-mechanical and thermo-hydro-geochemical performance assessment of a deep geological repository for high level radioactive wastes. These objectives require integrated theoretical and experimental development work. The experimental work consists of three parts: an in situ test, a mock-up test and a series of laboratory tests. The experiments is based on the Spanish reference concept for crystalline rock, in which the waste capsules are placed horizontally in drifts surround by high density compacted bentonite blocks. In the two large-scale tests, the thermal effects of the wastes were simulated by means of heaters; hydration was natural in the in situ test and controlled in the mock-up test. The large-scale tests, with their monitoring systems, have been in operation for more than two years. the demonstration has been achieved in the in situ test and there are great expectation that numerical models sufficiently validated for the near-field performance assessment will be achieved. (Author)

Shear-flow coupling in non-planar rock joints

International Nuclear Information System (INIS)

Makurat, A.; Barton, N.

1985-01-01

Crystalline rock masses are regarded as a possible host rock for permanent nuclear waste disposal. During the excavation of the required shafts and tunnels, the initial state of stress will be changed and cause a deformation of the rock mass and discontinuities. During the lifetime of the nuclear repository joint apertures may change due to thermally induced stress variations during the heating and cooling phase. As the conductivity of a joint is very sensitive to its aperture, fluid flow from and towards a repository, as well as the potential transport times of radionuclides are highly dependent on the deformability of the joints. Theoretical calculations of coupled flow in rock joints (Barton et al. 1984) predict an increase of conductivity of several orders of magnitude for the first few millimeters for shear displacement. The shear-dilation-conductivity coupling for two block sizes at two effective stress levels is shown

Image resolution influence on determination of resin injection rock mass

Science.gov (United States)

Wang, Weixing; Hakami, Eva

2006-01-01

In the context of nuclear waste repositories, an important approach to understanding brittle rock mass behavior to integrate new and powerful observational and numerical methods with multi-functional 3-D imaging and visualization techniques. Since 1994, Swedish Nuclear Fuel and Waste Management Company (SKB) have identified the need for a better understanding of radionuclide transport and retention processes in fractured rock. As a cooperation project between Sweden and China, we sampled a number of rock specimens for analyze rock fracture network by optical image technique. The samples are resin injected, in which way; opened fractures can be seen clearly by means of UV (Ultraviolet) light illumination. In the study period, we used different optical focuses to obtain the images from the same samples; we found that Image resolution influences on porosity determination of resin injected rock mass. This paper presents and discusses the six issues based on our research results: (1) Fracture porosity increases as camera focus distance decreases; (2) Porosity increases as illumination increases in resin injected fracture images; (3) To roughly estimate the porosity, the low resolution image can be used; (4) To collect more details of fracture information, the high resolution image is needed; (5) The resolution of image should be determined based on the aim of fracture analysis; (6) To acquire high resolution image, constructing a special illumination (standard) box maybe helpful to avoid light reflection and diffusion.

Grimsel test site. Research on safe geological disposal of radioactive waste

International Nuclear Information System (INIS)

2010-07-01

The Grimsel Test Site is located at an altitude of 1730 meters in the granitic formations of the Aare Massif. Some 300 million years ago, magmas solidified to form granitic rocks in the Grimsel area. New molten masses flowed into fissures of the cooling rock and formed dyke rocks. During the alpine orogeny around 40 million years ago, the rocks of the Aare Massif were passed over by the northwards-moving alpine layers and subsided by around 12 kilometres. The rocks were then overprinted under high temperature and pressure conditions and shear zones and fracture systems were formed. Uplift (0.5 to 0.8 mm/a) and erosion processes, which are still continuing today, brought the rocks of the Aare Massif to the surface once more. The mineral fractures for which the Grimsel area is famous, formed around 14 million years ago. Deep in the rock, the range of geological conditions found in the laboratory present ideal boundary conditions for investigating the functioning of both the geological and engineered barriers of deep repositories. Projects that look at the disposal concepts on a large scale are also an important aspect of the work at the Test Site. A radiation controlled zone allows radionuclides to be used under monitored conditions, giving a direct insight into the transport of radioactive substances in the rock. Around 25 partner organisations from various countries are involved in the projects at the Test Site. The European Union and the Swiss State Secretariat for Education and Research provide financial support to several experiments. In Switzerland, deep geological disposal is required by law for all types of radioactive waste. Field investigations for determining the suitability of potential disposal sites are an important component of a waste management programme. The field work is complemented by laboratory studies, investigations of relevant natural processes and research projects in underground rock laboratories; these provide a better understanding of the

Grimsel test site. Research on safe geological disposal of radioactive waste

Energy Technology Data Exchange (ETDEWEB)

NONE

2010-07-15

The Grimsel Test Site is located at an altitude of 1730 meters in the granitic formations of the Aare Massif. Some 300 million years ago, magmas solidified to form granitic rocks in the Grimsel area. New molten masses flowed into fissures of the cooling rock and formed dyke rocks. During the alpine orogeny around 40 million years ago, the rocks of the Aare Massif were passed over by the northwards-moving alpine layers and subsided by around 12 kilometres. The rocks were then overprinted under high temperature and pressure conditions and shear zones and fracture systems were formed. Uplift (0.5 to 0.8 mm/a) and erosion processes, which are still continuing today, brought the rocks of the Aare Massif to the surface once more. The mineral fractures for which the Grimsel area is famous, formed around 14 million years ago. Deep in the rock, the range of geological conditions found in the laboratory present ideal boundary conditions for investigating the functioning of both the geological and engineered barriers of deep repositories. Projects that look at the disposal concepts on a large scale are also an important aspect of the work at the Test Site. A radiation controlled zone allows radionuclides to be used under monitored conditions, giving a direct insight into the transport of radioactive substances in the rock. Around 25 partner organisations from various countries are involved in the projects at the Test Site. The European Union and the Swiss State Secretariat for Education and Research provide financial support to several experiments. In Switzerland, deep geological disposal is required by law for all types of radioactive waste. Field investigations for determining the suitability of potential disposal sites are an important component of a waste management programme. The field work is complemented by laboratory studies, investigations of relevant natural processes and research projects in underground rock laboratories; these provide a better understanding of the

Aspects of nuclear waste management

International Nuclear Information System (INIS)

Moberg, L.

1990-10-01

Six areas of concern in nuclear waste management have been dealt with in a four-year Nordic research programme. They include work in two international projects, Hydrocoin dealing with modelling of groundwater flow in crystalline rock, and Biomovs, concerned with biosphere models. Geologic questions of importance to the prediction of future behaviour are examined. Waste quantities from the decommissioning of nuclear power stations are estimated, and total amounts of waste to be transported in the Nordic countries are evaluated. Waste amounts from a hypothetical reactor accident are also calculated. (au)

Hygienic assessment of using rocks with high content of natural radionuclides in road construction

International Nuclear Information System (INIS)

Kornilov, A.N.; Ryabchikov, S.G.

1983-01-01

Experimental investigations on radiation hygienic assessment of the possibilities of using rocks with an increased content of natural radionuclides (NRN) are carried out. At experimental road portions constructed using such rocks, γ-radiation levels have been measured and radioactive contamination of the ad-- jacent territory has been determined. The danger presented by such roads for highway engineering workers and population also has been assessed. The results obtained permit to express a possitive opinion on the use of solid wastes with an increased NRN content for construction of roads with asphalt coating. Rocks with specific α-activity 3 Bq/kg are recommended to be used for any types of road construction, whereas wastes with specific α-activity 3 Bq/kg - only for road construction in an industrial zone, between populated areas and for thoroughfares and highways. The use of wastes with a higher NRN content is unreasonable as it leads to a growth of annular dose to population and excessive exposure of construction workers engaged in highway engineering operations

Quality assurance in management of geotechnical experiments for nuclear waste disposal

International Nuclear Information System (INIS)

Dormuth, K.W.; Simmons, G.R.

1992-01-01

Research and development (R and D) of technology for the disposal of nuclear fuel waste in plutonic rock is being undertaken in the Canadian Nuclear Fuel Waste Management Program, jointly funded by Atomic Energy of Canada Limited (AECL) Research and Ontario Hydro under the auspices of the CANDU Owner's Group. A major component of the R and D is geotechnical research to improve the understanding of the response of the host rock to a waste repository; investigate the interactions between the waste package, sealing systems, and rock; elucidate geotechnical factors affecting potential transport of waste elements from the repository; and establish and refine techniques and procedures for repository engineering. Nine major experimental activities are currently in various stages of planning and implementation at AECL's Underground Research Laboratory (URL). A general description of a quality assurance (QA) program developed at AECL for R and D on nuclear waste disposal has been published previously. This QA program is project-oriented and is designed specifically for and R and D environment. The full application of the QA program is being phased into the management of the operating phase experiments because some activities were under way prior to establishment of the QA program

Numerical simulation for excavation and long-term behavior of large-scale cavern in soft rock

International Nuclear Information System (INIS)

Sawada, Masataka; Okada, Tetsuji

2010-01-01

Low-level radioactive waste is planned to be disposed at the depth of more than 50 m in Neogene tuff or tuffaceous sandstone. Generally there are few cracks in sedimentary soft rocks, thus it is considered to be easier to determine permeability of soft rocks than that of discontinuous rocks. On the other hand, sedimentary soft rocks show strong time-dependent behavior, and they are more sensitive to heat, groundwater, and their chemical effect. Numerical method for long-term behavior of underground facilities is necessary to their design and safety assessment. Numerical simulations for excavation of test cavern in disposal site are described in this report. Our creep model was applied to these simulations. Although it is able to reproduce the behavior of soft rock observed in laboratory creep test, simulation using parameters obtained from laboratory tests predicts much larger displacement than that of measurement. Simulation using parameters modified based on in-situ elastic wave measurement and back analysis reproduces measured displacements very well. Behavior of the surrounding rock mass during resaturation after setting of the waste and the engineered barrier system is also simulated. We have a plan to investigate chemical and mechanical interaction among soft rock, tunnel supports and engineered barriers, and to make their numerical models. (author)

Waste package project quarterly report, April 1, 1995--June 30, 1995

International Nuclear Information System (INIS)

Ladkany, S.G.

1995-01-01

Research activities spanned multidisciplinary areas: structural and stress analysis of the container including nonlinear yield and damage assessment and structural stability studies of the dynamic behavior of the steel multipurpose container under normal and accidental handling conditions; nuclear fission criticality studies in the canisters; investigation of novel canister design concepts and corrosion studies; heat transfer studies of the waste canisters and in adjacent rock drifts; fluid flow in porous media and radionuclide transport in near field rock; stresses and stability of the rock formations resulting from thermal loading of fuel elements and multi-tunnel concept being analyzed; faulted rock tunnel model; and three link steel robot for remote handling of high level nuclear waste

Sorption of cesium in intact rock

International Nuclear Information System (INIS)

Puukko, E.

2014-04-01

The mass distribution coefficient K d is used in performance assessment (PA) to describe sorption of a radionuclide on rock. The R d is determined using crushed rock which causes uncertainty in converting the R d values to K d values for intact rock. This work describes a method to determine the equilibrium of sorption on intact rock. The rock types of the planned Olkiluoto waste disposal site were T-series mica gneiss (T-MGN), T-series tonalite granodiorite granite gneiss (T-TGG), P-series tonalite granodiorite granite gneiss (P-TGG) and pegmatitic granite (PGR). These rocks contain different amount of biotite which is the main sorbing mineral. The sorption of cesium on intact rock slices was studied by applying an electrical field to speed up migration of cesium into the rock. Cesium is in the solution as a noncomplex cation Cs + and it is sorbed by ion exchange. The tracer used in the experiments was 134 Cs. The experimental sorption on the intact rock is compared with values calculated using the in house cation exchange sorption model (HYRL model) in PHREEQC program. The observed sorption on T-MGN and T-TGG rocks was close to the calculated values. Two PGR samples were from a depth of 70 m and three samples were from a depth of 150 m. Cesium sorbed more than predicted on the two 70 m PGR samples. The sorption of Cs on the three 150 m PGR samples was small which was consistent with the calculations. The pegmatitic granite PGR has the smallest content of biotite of the four rock types. In the case of P-TGG rock the observed values of sorption were only half of the calculated values. Two kind of slices were cut from P-TGG drill core. The slices were against and to the direction of the foliation of the biotite rims. The sorption of cesium on P-TGG rock was same in both cases. The results indicated that there was no effect of the directions of the electric field and the foliation of biotite in the P-TGG rock. (orig.)

Compact rock material gas permeability properties

Energy Technology Data Exchange (ETDEWEB)

Wang, Huanling, E-mail: whl_hm@163.com [Key Laboratory of Coastal Disaster and Defence, Ministry of Education, Hohai University, Nanjing 210098 (China); LML, University of Lille, Cite Scientifique, 59655 Villeneuve d’Ascq (France); Xu, Weiya; Zuo, Jing [Institutes of Geotechnical Engineering, Hohai University, Nanjing 210098 (China)

2014-09-15

Natural compact rocks, such as sandstone, granite, and rock salt, are the main materials and geological environment for storing underground oil, gas, CO{sub 2,} shale gas, and radioactive waste because they have extremely low permeabilities and high mechanical strengths. Using the inert gas argon as the fluid medium, the stress-dependent permeability and porosity of monzonitic granite and granite gneiss from an underground oil storage depot were measured using a permeability and porosity measurement system. Based on the test results, models for describing the relationships among the permeability, porosity, and confining pressure of rock specimens were analyzed and are discussed. A power law is suggested to describe the relationship between the stress-dependent porosity and permeability; for the monzonitic granite and granite gneiss (for monzonitic granite (A-2), the initial porosity is approximately 4.05%, and the permeability is approximately 10{sup −19} m{sup 2}; for the granite gneiss (B-2), the initial porosity is approximately 7.09%, the permeability is approximately 10{sup −17} m{sup 2}; and the porosity-sensitivity exponents that link porosity and permeability are 0.98 and 3.11, respectively). Compared with moderate-porosity and high-porosity rocks, for which φ > 15%, low-porosity rock permeability has a relatively lower sensitivity to stress, but the porosity is more sensitive to stress, and different types of rocks show similar trends. From the test results, it can be inferred that the test rock specimens’ permeability evolution is related to the relative particle movements and microcrack closure.

Low- and intermediate level radioactive waste from Risoe, Denmark. Location studies for potential disposal areas. Report no. 2. Characterization of low permeable and fractured sediments and rocks in Denmark