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Sample records for nuclear waste repositories

  1. Coupled processes associated with nuclear waste repositories

    SciTech Connect

    Tsang, C.F.

    1987-01-01

    This book deals with coupled processes which affect a nuclear waste repository. While there are many descriptive accounts of environmental degradation resulting from various land uses, the author emphasizes the geomorphic processes responsible for such changes and the reasons why various reclamation practices are valuable in environmental management.

  2. Hydrologic issues associated with nuclear waste repositories

    NASA Astrophysics Data System (ADS)

    Tsang, Chin-Fu; Neretnieks, Ivars; Tsang, Yvonne

    2015-09-01

    Significant progress in hydrology, especially in subsurface flow and solute transport, has been made over the last 35 years because of sustained interest in underground nuclear waste repositories. The present paper provides an overview of the key hydrologic issues involved, and to highlight advances in their understanding and treatment because of these efforts. The focus is not on the development of radioactive waste repositories and their safety assessment, but instead on the advances in hydrologic science that have emerged from such studies. Work and results associated with three rock types, which are being considered to host the repositories, are reviewed, with a different emphasis for each rock type. The first rock type is fractured crystalline rock, for which the discussion will be mainly on flow and transport in saturated fractured rock. The second rock type is unsaturated tuff, for which the emphasis will be on flow from the shallow subsurface through the unsaturated zone to the repository. The third rock type is clay-rich formations, whose permeability is very low in an undisturbed state. In this case, the emphasis will be on hydrologic issues that arise from mechanical and thermal disturbances; i.e., on the relevant coupled thermo-hydro-mechanical processes. The extensive research results, especially those from multiyear large-scale underground research laboratory investigations, represent a rich body of information and data that can form the basis for further development in the related areas of hydrologic research.

  3. Constructibility issues associated with a nuclear waste repository in basalt

    SciTech Connect

    Turner, D.A.

    1981-12-04

    This report contains the text and slide reproductions of a speech on nuclear waste disposal in basalt. The presentation addresses the layout of repository access shafts and subsurface facilities resulting from the conceptual design of a nuclear repository in basalt. The constructibility issues that must be resolved prior to construction are described. (DMC)

  4. Siting Patterns of Nuclear Waste Repositories.

    ERIC Educational Resources Information Center

    Solomon, Barry D.; Shelley, Fred M.

    1988-01-01

    Provides an inventory of international radioactive waste-management policies and repository siting decisions for North America, Central and South America, Europe, Asia, and Africa. This discussion stresses the important role of demographic, geologic, and political factors in siting decisions. (Author/BSR)

  5. Public reactions to nuclear waste: Citizens' views of repository siting

    SciTech Connect

    Rosa, E.A.

    1993-01-01

    This book presents revised and updated papers from a panel of social scientists, at the 1989 AAAS meetings, that examined the public's reactions to nuclear waste disposal and the repository siting process. The papers report the results of original empirical research on citizens' views of nuclear waste repository siting. Topics covered include the following: content analysis of public testimony; sources of public concern about nuclear waste disposal in Texas agricultural communities; local attitudes toward high-level waste repository at Hanford; perceived risk and attitudes toward nuclear wastes; attitudes of Nevada urban residents toward a nuclear waste repository; attitudes of rural community residents toward a nuclear waste respository. An introductory chapter provides background and context, and a concluding chapter summarizes the implications of the reports. Two additional chapters cover important features of high-level waste disposal: long term trends in public attitudes toward nuclear energy and nuclear waste policy and assessment of the effects on the Los Vegas convention business if a high-level nuclear waste depository were sited in Nevada.

  6. Public concerns and choices regarding nuclear waste repositories

    SciTech Connect

    Rankin, W.L.; Nealey, S.M.

    1981-06-01

    Survey research on nuclear power issues conducted in the late 1970's has determined that nuclear waste management is now considered to be one of the most important nuclear power issues both by the US public and by key leadership groups. The purpose of this research was to determine the importance placed on specific issues associated with high-level waste disposal. In addition, policy option choices were asked regarding the siting of both low-level and high-level nuclear waste repositories. A purposive sampling strategy was used to select six groups of respondents. Averaged across the six respondent groups, the leakage of liquid wastes from storage tanks was seen as the most important high-level waste issue. There was also general agreement that the issue regarding water entering the final repository and carrying radioactive wastes away was second in importance. Overall, the third most important issue was the corrosion of the metal containers used in the high-level waste repository. There was general agreement among groups that the fourth most important issue was reducing safety to cut costs. The fifth most important issue was radioactive waste transportation accidents. Overall, the issues ranked sixth and seventh were, respectively, workers' safety and earthquakes damaging the repository and releasing radioactivity. The eighth most important issue, overall, was regarding explosions in the repository from too much radioactivity, which is something that is not possible. There was general agreement across all six respondent groups that the two least important issues involved people accidentally digging into the site and the issue that the repository might cost too much and would therefore raise electricity bills. These data indicate that the concerns of nuclear waste technologists and other public groups do not always overlap.

  7. Modeling transient heat transfer in nuclear waste repositories.

    PubMed

    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. PMID:19376651

  8. Selection of Corrosion Resistant Materials for Nuclear Waste Repositories

    SciTech Connect

    Rebak, R B

    2006-06-01

    Several countries are considering geological repositories to dispose of nuclear waste. The environment of most of the currently considered repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories alloys such as carbon steel, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

  9. Environmental Degradation of Materials for Nuclear Waste Repositories Engineered Barriers

    SciTech Connect

    Rebak, R B

    2006-12-24

    Several countries are considering geological repositories for the storage of nuclear waste. Most of the environments for these repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories, alloys such as carbon steel, copper, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

  10. Selection of Corrosion Resistant Materials for Nuclear Waste Repositories

    SciTech Connect

    R.B. Rebak

    2006-08-28

    Several countries are considering geological repositories to dispose of nuclear waste. The environment of most of the currently considered repositories will be reducing in nature, except for the repository in the US, which is going to be oxidizing. For the reducing repositories, alloys such as carbon steel, stainless steels and titanium are being evaluated. For the repository in the US, some of the most corrosion resistant commercially available alloys are being investigated. This paper presents a summary of the behavior of the different materials under consideration for the repositories and the current understanding of the degradation modes of the proposed alloys in ground water environments from the point of view of general corrosion, localized corrosion and environmentally assisted cracking.

  11. Thermohydeologic Behavior at the Potential Yucca Mountain Nuclear Waste Repository

    SciTech Connect

    Buscheck, T.A.; Rosenburg, N.D.; Gansemer, J.; Sun, Y.

    2000-02-17

    Radioactive decay of high-level nuclear waste emplaced in a Yucca Mountain repository will produce an initial heat flux on the order of 30 to 50 times the heat flux in the Geysers geothermal reservoir in California (Hardin et al., 1998). Even though the rate of heat production decreases rapidly with time after emplacement, this heat flux will change the thermal and hydrologic environment, affecting both the host rock and conditions within the drifts in ways significant to key repository performance variables.

  12. Expected brine movement at potential nuclear waste repository salt sites

    SciTech Connect

    McCauley, V.S.; Raines, G.E.

    1987-08-01

    The BRINEMIG brine migration code predicts rates and quantities of brine migration to a waste package emplaced in a high-level nuclear waste repository in salt. The BRINEMIG code is an explicit time-marching finite-difference code that solves a mass balance equation and uses the Jenks equation to predict velocities of brine migration. Predictions were made for the seven potentially acceptable salt sites under consideration as locations for the first US high-level nuclear waste repository. Predicted total quantities of accumulated brine were on the order of 1 m/sup 3/ brine per waste package or less. Less brine accumulation is expected at domal salt sites because of the lower initial moisture contents relative to bedded salt sites. Less total accumulation of brine is predicted for spent fuel than for commercial high-level waste because of the lower temperatures generated by spent fuel. 11 refs., 36 figs., 29 tabs.

  13. Rock mechanics for hard rock nuclear waste repositories

    SciTech Connect

    Heuze, F.E.

    1981-09-01

    The mined geologic burial of high level nuclear waste is now the favored option for disposal. The US National Waste Terminal Storage Program designed to achieve this disposal includes an extensive rock mechanics component related to the design of the wastes repositories. The plan currently considers five candidate rock types. This paper deals with the three hard rocks among them: basalt, granite, and tuff. Their behavior is governed by geological discontinuities. Salt and shale, which exhibit behavior closer to that of a continuum, are not considered here. This paper discusses both the generic rock mechanics R and D, which are required for repository design, as well as examples of projects related to hard rock waste storage. The examples include programs in basalt (Hanford/Washington), in granitic rocks (Climax/Nevada Test Site, Idaho Springs/Colorado, Pinawa/Canada, Oracle/Arizona, and Stripa/Sweden), and in tuff (Nevada Test Site).

  14. Can clays ensure nuclear waste repositories?

    PubMed

    Zaoui, A; Sekkal, W

    2015-01-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation. PMID:25742950

  15. Can clays ensure nuclear waste repositories?

    NASA Astrophysics Data System (ADS)

    Zaoui, A.; Sekkal, W.

    2015-03-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation.

  16. Can clays ensure nuclear waste repositories?

    PubMed Central

    Zaoui, A.; Sekkal, W.

    2015-01-01

    Research on argillite as a possible host rock for nuclear waste disposal is still an open subject since many issues need to be clarified. In the Underground Research Laboratories constructed for this purpose, a damaged zone around the excavation has been systematically observed and characterized by the appearance of micro-fissures. We analyse here -at nanoscale level- the calcite/clay assembly, the main constituents of argillite, under storage conditions and show the fragility of the montmorillonite with respect to calcite. Under anisotropic stress, we have observed a shear deformation of the assembly with the presence of broken bonds in the clay mineral, localised in the octahedral rather than the tetrahedral layers. The stress/strain curve leads to a failure strength point at 18.5 MPa. The obtained in-plane response of the assembly to perpendicular deformation is characterized by smaller perpendicular moduli Ez = 48.28 GPa compared to larger in-plane moduli Ex = 141.39 GPa and Ey = 134.02 GPa. Our calculations indicate the instability of the assembly without water molecules at the interface in addition to an important shear deformation. PMID:25742950

  17. Yucca Mountain nuclear waste repository prompts heated congressional hearing

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    2011-11-01

    Although the final report of the Blue Ribbon Commission on America's Nuclear Future is not expected until January 2012, the tentative conclusions of the commission's draft report were dissected during a recent joint hearing by two subcommittees of the House of Representatives' Committee on Science, Space, and Technology. Among the more heated issues debated at the hearing was the fate of the stalled Yucca Mountain nuclear waste repository in Nevada. The Blue Ribbon Commission's (BRC) draft report includes recommendations for managing nuclear waste and for developing one or more permanent deep geological repositories and interim storage facilities, but the report does not address the future of Yucca Mountain. The BRC charter indicates that the commission is to "conduct a comprehensive review of policies for managing the back end of the nuclear fuel cycle." However, the draft report states that the commission was not asked to consider, and therefore did not address, several key issues. "We have not rendered an opinion on the suitability of the Yucca Mountain site or on the request to withdraw the license application for Yucca Mountain," the draft report states.

  18. Geotechnical support and topical studies for nuclear waste geologic repositories

    SciTech Connect

    Not Available

    1989-01-01

    The present report lists the technical reviews and comments made during the fiscal year 1988 and summarizes the technical progress of the topical studies. In the area of technical assistance, there were numerous activities detailed in the next section. These included 24 geotechnical support activities, including reviews of 6 Study Plans (SP) and participation in 6 SP Review Workshops, review of one whole document Site Characterization Plan (SCP) and participation in the Assembled Document SCP Review Workshops by 6 LBL reviewers; the hosting of a DOE program review, the rewriting of the project statement of work, 2 trips to technical and planning meetings; preparation of proposed work statements for two new topics for DOE, and 5 instances of technical assistance to DOE. These activities are described in a Table in the following section entitled Geoscience Technical Support for Nuclear Waste Geologic Repositories.''

  19. Hydrogeologic effects of natural disruptive events on nuclear waste repositories

    SciTech Connect

    Davis, S.N.

    1980-06-01

    Some possible hydrogeologic effects of disruptive events that may affect repositories for nuclear wastte are described. A very large number of combinations of natural events can be imagined, but only those events which are judged to be most probable are covered. Waste-induced effects are not considered. The disruptive events discussed above are placed into four geologic settings. Although the geology is not specific to given repository sites that have been considered by other agencies, the geology has been generalized from actual field data and is, therefore, considered to be physically reasonable. The geologic settings considered are: (1) interior salt domes of the Gulf Coast, (2) bedded salt of southeastern New Mexico, (3) argillaceous rocks of southern Nevanda, and (4) granitic stocks of the Basin and Range Province. Log-normal distributions of permeabilities of rock units are given for each region. Chapters are devoted to: poresity and permeability of natural materials, regional flow patterns, disruptive events (faulting, dissolution of rock forming minerals, fracturing from various causes, rapid changes of hydraulic regimen); possible hydrologic effects of disruptive events; and hydraulic fracturing.

  20. Ultrafine cement grout for sealing underground nuclear waste repositories

    SciTech Connect

    Ahrens, E.H.; Onofrei, M.

    1996-02-01

    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 their host. This paper presents the results of collaborative work between Whitesell Laboratories, operated by Atomic Energy of Canada, Ltd., and Sandia National Laboratories; the work was undertaken in support of the Waste Isolation Pilot Plant (WIPP). 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 plugging and sealing program, specifically the development and optimization of Ultrafine cementitious grout that can be injected to adequately lower excessive, strain-induced permeability in the Distributed Rock Zone (DRZ) surrounding underground excavations. Innovative equipment and procedures employed in the laboratory produced a usable cement-based grout whose particles are 90% smaller than 8 microns and average 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 8 microns and lowered the gas permeability of the DRZ by three orders of magnitude. Following the WIPP test, additional work produced an improved version of the grout containing particles 90% smaller than 6 microns and averaging 2 microns. This grout can be produced in the dry form at a competitive cost ready to mix.

  1. Waste package performance evaluations for the proposed high-level nuclear waste repository at Yucca Mountain.

    PubMed

    Mon, Kevin G; Bullard, Bryan E; Mehta, Sunil; Lee, Joon H

    2004-04-01

    The evaluation studies of the proposed repository for long-term storage of spent nuclear fuel and high-level nuclear waste at Yucca Mountain, Nevada, are underway. Fulfillment of the requirements for limiting dose to the public, which includes containment of the radioactive waste emplaced in the proposed repository and subsequent slow release of radionuclides from the Engineered Barrier System (EBS) into the geosphere, will rely on a robust waste container design, among other EBS components. Part of the evaluation process involves sensitivity studies aimed at elucidating which model parameters contribute most to the waste package and overlying drip shield degradation characteristics. The model parameters identified for this study include (1) general corrosion rate parameters and (2) stress corrosion cracking (SCC) parameters. Temperature dependence and parameter uncertainty are evaluated for the general corrosion rate model parameters while for the SCC model parameters, uncertainty treatment of stress intensity factor, crack initiation threshold, and manufacturing flaw orientations are evaluated. Based on these evaluations new uncertainty distributions are generated and recommended for future analyses. Also, early waste package failures due to improper heat treatment were added to the waste package degradation model. The results of these investigations indicate that the waste package failure profiles are governed by the manufacturing flaw orientation model parameters. PMID:15078313

  2. Development of reference conditions for geologic repositories for nuclear waste in the USA

    SciTech Connect

    Raines, G.E.; Rickertsen, L.D.; Claiborne, H.C.; McElroy, J.L.; Lynch, R.W.

    1980-10-01

    Activities to determine interim reference conditions for temperatures, pressure, fluid, chemical, and radiation environments that are expected to exist in commercial and defense high-level nuclear waste and spent fuel repositories in salt, basalt, tuff, granite, and shale are summarized. These interim conditions are being generated by the Reference Repository Conditions Interface Working Groups (RRC-IWG), an ad hoc IWG established by the National Waste Terminal Storage Program's (NWTS) Isolation Interface Control Board (I-ICB).

  3. Fault Frictional Stability in a Nuclear Waste Repository

    NASA Astrophysics Data System (ADS)

    Orellana, Felipe; Violay, Marie; Scuderi, Marco; Collettini, Cristiano

    2016-04-01

    Exploitation of underground resources induces hydro-mechanical and chemical perturbations in the rock mass. In response to such disturbances, seismic events might occur, affecting the safety of the whole engineering system. The Mont Terri Rock Laboratory is an underground infrastructure devoted to the study of geological disposal of nuclear waste in Switzerland. At the site, it is intersected by large fault zones of about 0.8 - 3 m in thickness and the host rock formation is a shale rock named Opalinus Clay (OPA). The mineralogy of OPA includes a high content of phyllosilicates (50%), quartz (25%), calcite (15%), and smaller proportions of siderite and pyrite. OPA is a stiff, low permeable rock (2×10-18 m2), and its mechanical behaviour is strongly affected by the anisotropy induced by bedding planes. The evaluation of fault stability and associated fault slip behaviour (i.e. seismic vs. aseismic) is a major issue in order to ensure the long-term safety and operation of the repository. Consequently, experiments devoted to understand the frictional behaviour of OPA have been performed in the biaxial apparatus "BRAVA", recently developed at INGV. Simulated fault gouge obtained from intact OPA samples, were deformed at different normal stresses (from 4 to 30 MPa), under dry and fluid-saturated conditions. To estimate the frictional stability, the velocity-dependence of friction was evaluated during velocity steps tests (1-300 μm/s). Slide-hold-slide tests were performed (1-3000 s) to measure the amount of frictional healing. The collected data were subsequently modelled with the Ruina's slip dependent formulation of the rate and state friction constitutive equations. To understand the deformation mechanism, the microstructures of the sheared gouge were analysed. At 7 MPa normal stress and under dry conditions, the friction coefficient decreased from a peak value of μpeak,dry = 0.57 to μss,dry = 0.50. Under fluid-saturated conditions and same normal stress, the

  4. Backfill composition for secondary barriers in nuclear waste repositories

    DOEpatents

    Beall, G.W.; Allard, B.M.

    1980-05-30

    A backfill composition for sorbing and retaining hazardous elements of nuclear wastes comprises 50 to 70% by weight of quartz, 10 to 30% by weight of montmorillonite, 1 to 10% by weight of phosphate mineral, 1 to 10% by weight of ferrous mineral, 1 to 10% by weight of sulfate mineral and 1 to 10% by weight of attapulgite.

  5. Backfill composition for secondary barriers in nuclear waste repositories

    DOEpatents

    Beall, Gary W.; Allard, Bert M.

    1982-01-01

    A backfill composition for sorbing and retaining hazardous elements of nuclear wastes comprises 50-70% by weight of quartz, 10-30% by weight of montmorillonite, 1-10% by weight of phosphate mineral, 1-10% by weight of ferrous mineral, 1-10% by weight of sulfate mineral and 1-10% by weight of attapulgite.

  6. Retrieval effects on ventilation and cooling requirements for a nuclear waste repository

    SciTech Connect

    Hambley, D.F.

    1985-01-01

    The Nuclear Waste Policy Act of 1982 (Public Law 97-425) and the regulations promulgated in Title 10, Part 60 of the Code of Federal Regulations (10CFR60) by the US Nuclear Regulatory Commission (NRC) for an underground repository for spent fuel and high level nuclear waste (HLW) require that it is possible to retrieve waste, for whatever reason, from such a facility for a period of 50 years from initial storage or until the completion of the performance confirmation period, whichever comes first. This paper considers the effects that the retrievability option mandates on ventilation and cooling systems required for normal repository operations. An example is given for a hypothetical repository in salt. 18 refs., 1 tab.

  7. Engineered barrier development for a nuclear waste repository in basalt: an integration of current knowledge

    SciTech Connect

    Smith, M.J.

    1980-05-01

    This document represents a compilation of data and interpretive studies conducted as part of the engineered barriers program of the Basalt Waste Isolation Project. The overall objective of these studies is to provide information on barrier system designs, emplacement and isolation techniques, and chemical reactions expected in a nuclear waste repository located in the basalts underlying the Hanford Site within the state of Washington. Backfills, waste-basalt interactions, sorption, borehole plugging, etc., are among the topics discussed.

  8. Potential Biogenic Corrosion of Alloy 22, A Candidate Nuclear Waste Packaging Materials, Under Simulated Repository Conditions

    SciTech Connect

    Horn, J.M.; Martin, S.I.; Rivera, A.J.; Bedrossian, P.J.; Lian, T.

    2000-01-12

    The U.S. Department of Energy has been charged with assessing the suitability of a geologic nuclear waste repository at Yucca Mountain (YM), NV. Microorganisms, both those endogenous to the repository site and those introduced as a result of construction and operational activities, may contribute to the corrosion of metal nuclear waste packaging and thereby decrease their useful lifetime as barrier materials. Evaluation of potential Microbiological Influenced Corrosion (MIC) on candidate waste package materials was undertaken reactor systems incorporating the primary elements of the repository: YM rock (either non-sterile or presterilized), material coupons, and a continual feed of simulated YM groundwater. Periodically, both aqueous reactor efflux and material coupons were analyzed for chemical and surfacial characterization. Alloy 22 coupons exposed for a year at room temperature in reactors containing non-sterile YM rock demonstrated accretion of chromium oxide and silaceous scales, with what appear to be underlying areas of corrosion.

  9. Natural geochemical analogues of the near field of high-level nuclear waste repositories

    SciTech Connect

    Apps, J.A.

    1995-09-01

    United States practice has been to design high-level nuclear waste (HLW) geological repositories with waste densities sufficiently high that repository temperatures surrounding the waste will exceed 100{degrees}C and could reach 250{degrees}C. Basalt and devitrified vitroclastic tuff are among the host rocks considered for waste emplacement. Near-field repository thermal behavior and chemical alteration in such rocks is expected to be similar to that observed in many geothermal systems. Therefore, the predictive modeling required for performance assessment studies of the near field could be validated and calibrated using geothermal systems as natural analogues. Examples are given which demonstrate the need for refinement of the thermodynamic databases used in geochemical modeling of near-field natural analogues and the extent to which present models can predict conditions in geothermal fields.

  10. Anticipated Degradation Modes of Metallic Engineered Barriers for High-Level Nuclear Waste Repositories

    NASA Astrophysics Data System (ADS)

    Rodríguez, Martín A.

    2014-03-01

    Metallic engineered barriers must provide a period of absolute containment to high-level radioactive waste in geological repositories. Candidate materials include copper alloys, carbon steels, stainless steels, nickel alloys, and titanium alloys. The national programs of nuclear waste management have to identify and assess the anticipated degradation modes of the selected materials in the corresponding repository environment, which evolves in time. Commonly assessed degradation modes include general corrosion, localized corrosion, stress-corrosion cracking, hydrogen-assisted cracking, and microbiologically influenced corrosion. Laboratory testing and modeling in metallurgical and environmental conditions of similar and higher aggressiveness than those expected in service conditions are used to evaluate the corrosion resistance of the materials. This review focuses on the anticipated degradation modes of the selected or reference materials as corrosion-resistant barriers in nuclear repositories. These degradation modes depend not only on the selected alloy but also on the near-field environment. The evolution of the near-field environment varies for saturated and unsaturated repositories considering backfilled and unbackfilled conditions. In saturated repositories, localized corrosion and stress-corrosion cracking may occur in the initial aerobic stage, while general corrosion and hydrogen-assisted cracking are the main degradation modes in the anaerobic stage. Unsaturated repositories would provide an oxidizing environment during the entire repository lifetime. Microbiologically influenced corrosion may be avoided or minimized by selecting an appropriate backfill material. Radiation effects are negligible provided that a thick-walled container or an inner shielding container is used.

  11. Instrument reliability for high-level nuclear-waste-repository applications

    SciTech Connect

    Rogue, F.; Binnall, E.P.; Armantrout, G.A.

    1983-01-31

    Reliable instrumentation will be needed to evaluate the characteristics of proposed high-level nuclear-wasted-repository sites and to monitor the performance of selected sites during the operational period and into repository closure. A study has been done to assess the reliability of instruments used in Department of Energy (DOE) waste repository related experiments and in other similar geological applications. The study included experiences with geotechnical, hydrological, geochemical, environmental, and radiological instrumentation and associated data acquisition equipment. Though this paper includes some findings on the reliability of instruments in each of these categories, the emphasis is on experiences with geotechnical instrumentation in hostile repository-type environments. We review the failure modes, rates, and mechanisms, along with manufacturers modifications and design changes to enhance and improve instrument performance; and include recommendations on areas where further improvements are needed.

  12. Rock mass modification around a nuclear waste repository in welded tuff

    SciTech Connect

    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.

  13. Science Is the First Step to Siting Nuclear Waste Repositories

    NASA Astrophysics Data System (ADS)

    Neuzil, C. E.

    2014-02-01

    As Shaw [2014] notes, U.S. research on shale as a repository host was halted before expending anything close to the effort devoted to studying crystalline rock, salt, and—most notably—tuff at Yucca Mountain. The new political reality regarding Yucca Mountain may allow reconsideration of the decision to abandon research on shale as a repository host.

  14. Panel report on coupled thermo-mechanical-hydro-chemical processes associated with a nuclear waste repository

    SciTech Connect

    Tsang, C.F.; Mangold, D.C.

    1984-07-01

    Four basic physical processes, thermal, hydrological, mechanical and chemical, are likely to occur in 11 different types of coupling during the service life of an underground nuclear waste repository. A great number of coupled processes with various degrees of importance for geological repositories were identified and arranged into these 11 types. A qualitative description of these processes and a tentative evaluation of their significance and the degree of uncertainty in prediction is given. Suggestions for methods of investigation generally include, besides theoretical work, laboratory and large scale field testing. Great efforts of a multidisciplinary nature are needed to elucidate details of several coupled processes under different temperature conditions in different geological formations. It was suggested that by limiting the maximum temperature to 100{sup 0}C in the backfill and in the host rock during the whole service life of the repository the uncertainties in prediction of long-term repository behavior might be considerably reduced.

  15. Geochemical modeling of the nuclear-waste repository system. A status report

    SciTech Connect

    Deutsch, W.J.

    1980-12-01

    The primary objective of the geochemical modeling task is to develop an understanding of the waste-repository geochemical system and provide a valuable tool for estimating future states of that system. There currently exists a variety of computer codes which can be used in geochemical modeling studies. Some available codes contain the framework for simulating a natural chemical system and estimating, within limits, the response of that system to environmental changes. By data-base enhancement and code development, this modeling technique can be even more usefully applied to a nuclear-waste repository. In particular, thermodynamic data on elements not presently in the data base but identified as being of particular hazard in the waste-repository system, need to be incorporated into the code to estimate the near-field as well as the far-field reactions during a hypothetical breach. A reaction-path-simulation code, which estimates the products of specific rock/water reactions, has been tested using basalt and ground water. Results show that the mass-transfer capabilities of the code will be useful in chemical-evolution studies and scenario analyses. The purpose of this report is to explain the status of geochemical modeling as it currently applies to the chemical system of a hypothetical nuclear-waste repository in basalt and to present the plan proposed for further developmet and application.

  16. Summary of four release consequence analyses for hypothetical nuclear waste repositories in salt and granite

    SciTech Connect

    Cole, C.R.; Bond, F.W.

    1980-12-01

    Release consequence methology developed under the Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) program has now been applied to four hypothetical repository sites. This paper summarizes the results of these four studies in order to demonstrate that the far-field methodology developed under the AEGIS program offers a practical approach to the post-closure safety assessment of nuclear waste repositories sited in deep continental geologic formations. The four studies are briefly described and compared according to the following general categories: physical description of the repository (size, inventory, emplacement depth); geologic and hydrologic description of the site and the conceptual hydrologic model for the site; description of release scenario; hydrologic model implementation and results; engineered barriers and leach rate modeling; transport model implementation and results; and dose model implementation and results. These studies indicate the following: numerical modeling is a practical approach to post-closure safety assessment analysis for nuclear waste repositories; near-field modeling capability needs improvement to permit assessment of the consequences of human intrusion and pumping well scenarios; engineered barrier systems can be useful in mitigating consequences for postulated release scenarios that short-circuit the geohydrologic system; geohydrologic systems separating a repository from the natural biosphere discharge sites act to mitigate the consequences of postulated breaches in containment; and engineered barriers of types other than the containment or absorptive type may be useful.

  17. High level nuclear waste repository in salt: Sealing systems status and planning report: Draft report

    SciTech Connect

    1985-09-01

    This report documents the initial conceptual design studies for a repository sealing system for a high-level nuclear waste repository in salt. The first step in the initial design studies was to review the current design level, termed schematic designs. This review identified practicality of construction and development of a design methodology as two key issues for the conceptual design. These two issues were then investigated during the initial design studies for seal system materials, seal placement, backfill emplacement, and a testing and monitoring plan. The results of these studies have been used to develop a program plan for completion of the sealing system conceptual design. 60 refs., 26 figs., 18 tabs.

  18. NWTS program criteria for mined geologic disposal of nuclear waste: repository performance and development criteria. Public draft

    SciTech Connect

    1982-07-01

    This document, DOE/NWTS-33(3) is one of a series of documents to establish the National Waste Terminal Storage (NWTS) program criteria for mined geologic disposal of high-level radioactive waste. For both repository performance and repository development it delineates the criteria for design performance, radiological safety, mining safety, long-term containment and isolation, operations, and decommissioning. The US Department of Energy will use these criteria to guide the development of repositories to assist in achieving performance and will reevaluate their use when the US Nuclear Regulatory Commission issues radioactive waste repository rules.

  19. Climate considerations in long-term safety assessments for nuclear waste repositories.

    PubMed

    Näslund, Jens-Ove; Brandefelt, Jenny; Liljedahl, Lillemor Claesson

    2013-05-01

    For a deep geological repository for spent nuclear fuel planned in Sweden, the safety assessment covers up to 1 million years. Climate scenarios range from high-end global warming for the coming 100 000 years, through deep permafrost, to large ice sheets during glacial conditions. In contrast, in an existing repository for short-lived waste the activity decays to low levels within a few tens of thousands of years. The shorter assessment period, 100 000 years, requires more focus on climate development over the coming tens of thousands of years, including the earliest possibility for permafrost growth and freezing of the engineered system. The handling of climate and climate change in safety assessments must be tailor-made for each repository concept and waste type. However, due to the uncertain future climate development on these vast time scales, all safety assessments for nuclear waste repositories require a range of possible climate scenarios. PMID:23619797

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

    SciTech Connect

    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.

  1. Deep geological isolation of nuclear waste: numerical modeling of repository scale hydrology

    SciTech Connect

    Dettinger, M.D.

    1980-04-01

    The Scope of Work undertaken covers three main tasks, described as follows: (Task 1) CDM provided consulting services to the University on modeling aspects of the study having to do with transport processes involving the local groundwater system near the repository and the flow of fluids and vapors through the various porous media making up the repository system. (Task 2) CDM reviewed literature related to repository design, concentrating on effects of the repository geometry, location and other design factors on the flow of fluids within the repository boundaries, drainage from the repository structure, and the eventual transport of radionucldies away from the repository site. (Task 3) CDM, in a joint effort with LLL personnel, identified generic boundary and initial conditions, identified processes to be modeled, and recommended a modeling approach with suggestions for appropriate simplifications and approximations to the problem and identifiying important parameters necessary to model the processes. This report consists of two chapters and an appendix. The first chapter (Chapter III of the LLL report) presents a detailed description and discussion of the modeling approach developed in this project, its merits and weaknesses, and a brief review of the difficulties anticipated in implementing the approach. The second chapter (Chapter IV of the LLL report) presents a summary of a survey of researchers in the field of repository performance analysis and a discussion of that survey in light of the proposed modeling approach. The appendix is a review of the important physical processes involved in the potential hydrologic transport of radionuclides through, around and away from deep geologic nuclear waste repositories.

  2. A conceptual subsurface facility design for a high-level nuclear waste repository at Yucca Mountain

    SciTech Connect

    McKenzie, D.G., III; Bhattacharyya, K.K.; Segrest, A.M.

    1996-09-01

    The US Department of Energy is responsible for the design, construction, operation and closure of a repository in which to permanently dispose of the nation`s high level nuclear waste. In addition to the objective of safely isolating the waste inventory, the repository must provide a safe working environment for its workforce, and protect the public. The conceptual design for this facility is currently being developed. Tunnel Boring Machine will be used to excavate 228 kilometers of tunneling to construct the facility over a 30 year period. The excavation operations will be physically separated from the waste emplacement operations, and each operation will have its own dedicated ventilation system. The facility is being designed to remain open for 150 years.

  3. Consideration of criticality in a nuclear waste repository

    SciTech Connect

    Rechard, R.P.; Sanchez, L.C.; Stockman, C.T.; Ramsey, J.L. Jr.; Martell, M.

    1995-07-01

    The preliminary criticality analysis that was done suggests that the possibility of achieving critical conditions cannot be easily ruled out without looking at the geochemical process of assembly or the dynamics of the operation of a critical assembly. The evaluation of a critical assembly requires an integrated, consistent approach that includes evaluating the following: (1) the alteration rates of the layers of the container and spent fuel, (2) the transport of fissile material or neutron absorbers, and (3) the assembly mechanisms that can achieve critical conditions. The above is a non-trivial analysis and preliminary work suggests that with the loading assumed, enough fissile mass will leach from the HEU multi-purpose canisters to support a criticality. In addition, the consequences of an unpressurized Oklo type criticality would be insignificant to the performance of an unsaturated, tuff repository.

  4. Nuclear waste repository siting and locational conflict analysis: A contextual approach

    SciTech Connect

    Murauskas, G.T.

    1989-01-01

    This study develops and evaluates an alternative framework that is based on contextual variables. The premise is that differences in attitudes and perceptions regarding the local siting of nuclear wastes and differences in attitudes regarding siting decision-making procedures are influenced by local political, economic, and cultural variables. This framework articulates the nature of conflict in terms of the incongruence between the use-value individuals ascribe to their present situation and the anticipated exchange-value individuals associate with the local siting of a nuclear waste repository. In order to evaluate this conceptual framework a survey was conducted of residents in four communities representing distinct societal contexts: Richton, Mississippi; Peterborough, New Hampshire; Richland, Washington; and Antigo/Waupaca, Wisconsin. Data analyses indicate substantial differences in economic expectations associated with the local siting of a high-level nuclear waste repository and in perception regarding the impacts such a repository might have on the environment, local agriculture, personal health and safety, and the quality of life.

  5. Spatial patterns of radiological dose from wells drilled near nuclear waste repositories

    SciTech Connect

    Not Available

    1980-03-31

    This report describes methodology for assessing the spatial patterns of radiological dose to man from wells drilled near nuclear waste repositories. Descriptions of the various categories of water wells and a model of a typical aquifer are presented. The equation governing the one-dimensional flow of waste in groundwater through porous media to a well is discussed. This is followed by development of a method for constructing lines of constant dose from a well located randomly in the plane of the aquifer. An area of hazard, in which the dose to man from a well exceeds a given statuatory or recommended limit, is then defined within this dose pattern. This technique is then used to compute dose and hazard profiles for wells adjacent to a repository located in either impermeable or permeable bedded salt. The repository and geologic parameters employed in this example are taken from a Lawrence Livermore Laboratory report for which this report serves as a supporting document. Scenarios with impermeable salt involve waste entering the repository through the shaft/tunnel fracture zone and exiting through a single additional flaw (borehole). Permeable-salt scenarios involve waste escaping from the repsitory through a borehole and via interstitial flow. Calculations are performed assuming both a single-layer (sandstone) aquifer and a double-layer (sandstone/shale) aquifer in the strate overlying the repository. Results indicate a time-varying area of hazard from well drilling, whose size depends on the permeability of the salt, the regional hydrology, and the surface ecosystem assumed in the potential hazard calculations.

  6. Investigating the Thermal Limit of Clay Minerals for Applications in Nuclear Waste Repository Design

    NASA Astrophysics Data System (ADS)

    Matteo, E. N.; Miller, A. W.; Kruichak, J.; Mills, M.; Tellez, H.; Wang, Y.

    2013-12-01

    Clay minerals are likely candidates to aid in nuclear waste isolation due to their low permeability, favorable swelling properties, and high cation sorption capacities. Establishing the thermal limit for clay minerals in a nuclear waste repository is a potentially important component of repository design, as flexibility of the heat load within the repository can have a major impact on the selection of repository design. For example, the thermal limit plays a critical role in the time that waste packages would need to cool before being transferred to the repository. Understanding the chemical and physical changes that occur in clay minerals at various temperatures above the current thermal limit (of 100 °C) can enable decision-makers with information critical to evaluating the potential trade-offs of increasing the thermal limit within the repository. Most critical is gaining understanding of how varying thermal conditions in the repository will impact radionuclide sorption and transport in clay materials either as engineered barriers or as disposal media. A variety of clays (illite, mixed layer illite/smectite, montmorillonite, and palygorskite) were heated for a range of temperatures between 100-500 °C. These samples were characterized by a variety of methods, including nitrogen adsorption, x-ray diffraction, thermogravimetric analysis, barium chloride exchange for cation exchange capacity (CEC), and iodide sorption. The nitrogen porosimetry shows that for all the clays, thermally-induced changes in BET surface area are dominated by collapse/creation of the microporosity, i.e. pore diameters < 17 angstroms. Changes in micro porosity (relative to no heat treatment) are most significant for heat treatments 300 °C and above. Alterations are also seen in the chemical properties (CEC, XRD, iodide sorption) of clays, and like pore size distribution changes, are most significant above 300 °C. Overall, the results imply that changes seen in pores size distribution

  7. Expected near-field thermal performance for nuclear waste repositories at potential salt sites: Technical report

    SciTech Connect

    McNulty, E.G.

    1987-08-01

    Thermal analyses were made for the environmental assessments of seven potential salt sites for a nuclear waste repository. These analyses predicted that potential repository sites in domal salts located in the Gulf Coast will experience higher temperature than those in bedded salts of Paradox and Palo Duro Basins, mainly because of higher ambient temperatures at depth. The TEMPV5 code, a semi-analytical heat transfer code for finite line sources, calculated temperatures for commercial high-level waste (CHLW) and spent fuel from pressurized-water reactors (SFPWR). Benchmarks with HEATING6, THAC-SIP-3D, STEALTH, and SPECTROM-41 showed that TEMPV5 agreed closely in the very near field around the waste package and approximately in the near-field and far-field regions of the repository. The analyses used site-specific thermal conductivities that were increased by 40% to compensate for reductions caused by testing technique, salt impurities, and other heterogeneities, and sampling disturbance. Analyses showed peak salt temperatures of 236/sup 0/C (CHLW) and 134/sup 0/C (SFPWR) for the bedded salt and 296/sup 0/C (CHLW) and 180/sup 0/C (SFPWR) for the domal salt. Analyses with uncorrected laboratory thermal conductivities would increase peak salt temperatures by about 120/sup 0/C for CHLW and about 60/sup 0/C for SFPWR. These temperature increases would increase the thermally induced flow of brine and accelerate corrosion of the waste package. 30 refs., 35 figs., 48 tabs.

  8. Coupling of Nuclear Waste Form Corrosion and Radionuclide Transports in Presence of Relevant Repository Sediments

    SciTech Connect

    Wall, Nathalie A.; Neeway, James J.; Qafoku, Nikolla P.; Ryan, Joseph V.

    2015-09-30

    Assessments of waste form and disposal options start with the degradation of the waste forms and consequent mobilization of radionuclides. Long-term static tests, single-pass flow-through tests, and the pressurized unsaturated flow test are often employed to study the durability of potential waste forms and to help create models that predict their durability throughout the lifespan of the disposal site. These tests involve the corrosion of the material in the presence of various leachants, with different experimental designs yielding desired information about the behavior of the material. Though these tests have proved instrumental in elucidating various mechanisms responsible for material corrosion, the chemical environment to which the material is subject is often not representative of a potential radioactive waste repository where factors such as pH and leachant composition will be controlled by the near-field environment. Near-field materials include, but are not limited to, the original engineered barriers, their resulting corrosion products, backfill materials, and the natural host rock. For an accurate performance assessment of a nuclear waste repository, realistic waste corrosion experimental data ought to be modeled to allow for a better understanding of waste form corrosion mechanisms and the effect of immediate geochemical environment on these mechanisms. Additionally, the migration of radionuclides in the resulting chemical environment during and after waste form corrosion must be quantified and mechanisms responsible for migrations understood. The goal of this research was to understand the mechanisms responsible for waste form corrosion in the presence of relevant repository sediments to allow for accurate radionuclide migration quantifications. The rationale for this work is that a better understanding of waste form corrosion in relevant systems will enable increased reliance on waste form performance in repository environments and potentially

  9. Long-Term Waste Package Degradation Studies at the Yucca Mountain Potential High-Level Nuclear Waste Repository

    SciTech Connect

    Mon, K. G.; Bullard, B. E.; Longsine, D. E.; Mehta, S.; Lee, J. H.; Monib, A. M.

    2002-02-26

    The Site Recommendation (SR) process for the potential repository for spent nuclear fuel (SNF) and high-level nuclear waste (HLW) at Yucca Mountain, Nevada is underway. Fulfillment of the requirements for substantially complete containment of the radioactive waste emplaced in the potential repository and subsequent slow release of radionuclides from the Engineered Barrier System (EBS) into the geosphere will rely on a robust waste container design, among other EBS components. Part of the SR process involves sensitivity studies aimed at elucidating which model parameters contribute most to the drip shield and waste package degradation characteristics. The model parameters identified included (a) general corrosion rate model parameters (temperature-dependence and uncertainty treatment), and (b) stress corrosion cracking (SCC) model parameters (uncertainty treatment of stress and stress intensity factor profiles in the Alloy 22 waste package outer barrier closure weld regions, the SCC initiation stress threshold, and the fraction of manufacturing flaws oriented favorably for through-wall penetration by SCC). These model parameters were reevaluated and new distributions were generated. Also, early waste package failures due to improper heat treatment were added to the waste package degradation model. The results of these investigations indicate that the waste package failure profiles are governed by the manufacturing flaw orientation model parameters and models used.

  10. Use of swelling clays to reduce permeability and its potential application to nuclear waste repository sealing

    NASA Astrophysics Data System (ADS)

    Moore, D. E.; Morrow, C. A.; Byerlee, J. D.

    1982-09-01

    The injection of swelling-clay slurries into joints or faults at a deep-burial nuclear waste disposal site may result in significant permeability reductions for the effective containment of radioactive wastes. In an experiment conducted to illustrate the permeability change accompanying clay swelling, a coarse stone with interconnected pore spaces was injected with a clay-electrolyte slurry, modelling the pressure-grouting of a fractured repository rock. Subsequently, solutions with lower electrolyte concentrations were driven through the clay-filled stone, corresponding to migration of lower salinity ground-waters through the clay-grouted fracture. The initial injection procedure reduced the permeability of the stone from 1-10 darcies to 700 nanodarcies; the changes in solution composition decreased permeability by more than 2 additional orders of magnitude to 3 nanodarcies. For application at a nuclear waste repository, the electrolyte concentration of the injected clay slurry should be made higher than that of the ground-water in the host rock. Subsequent interaction of the ground-water with the clays would initiate swelling and create the additional, post-injection permeability reductions that may be important in preventing the escape of buried radioactive wastes. The measured permeability of the clay filling is considerably lower than that of cement tested for borehole plugging. Clays also have the advantage over cement and chemical grouts in that they are geologically stable at relatively low temperatures and have a high capacity for radionuclide adsorption.

  11. Validation of the physico-chemical processes determining the state of the components of liquid nuclear wastes in underground repositories

    SciTech Connect

    Kosareva, I.M.; Savushkina, M.K.; Egorov, N.N.; Kudryavtsev, E.G.; Chizhikov, V.S.; Korotkevich, V.M.; Revenko, Yu.A.; Nosukhin, A.V.

    1995-12-31

    This paper presents the results of a study of the physico-chemical properties of liquid nuclear wastes formed during the treatment of wastes of nuclear enterprises and nuclear power plants. The parameters of underground layers which can be used for the disposal of liquid nuclear wastes are discussed. When wastes are injected into a collector layer, various chemical interactions occur which may change the compositions of the wastes and the collector layer. To predict the state of the waste components during the dangerous period of the repository operation, a physico-chemical study of the processes occurring in nuclear waste repositories was carried out. For each type of waste, main peculiarities of possible transformations, including chemical interactions, hydrolysis, thermolysis, radiolysis, and sorption were determined. The disposal of liquid nuclear wastes into deep geological formations is a unique pilot experiment on the concentration of liquid nuclear wastes in a comparatively small area of an underground collector layer. This makes the implementation of the method and the period after the end of the operation of the repositories, i.e., their conservation, essential stages of this work. The development of the method of disposing of liquid nuclear wastes deep in water-bearing layers was carried out along several lines: (1) a comprehensive geohydrological study of the matter; (2) a study of the physico-chemical conditions of the disposal; (3) solution of scientific and technological problems; and (4) control and assessment of sanitary radiation safety. To exercise control over the state of deep underground repositories of liquid nuclear wastes, various mathematical models are being developed.

  12. Role of geophysics in identifying and characterizing sites for high-level nuclear waste repositories.

    USGS Publications Warehouse

    Wynn, J.C.; Roseboom, E.H.

    1987-01-01

    Evaluation of potential high-level nuclear waste repository sites is an area where geophysical capabilities and limitations may significantly impact a major governmental program. Since there is concern that extensive exploratory drilling might degrade most potential disposal sites, geophysical methods become crucial as the only nondestructive means to examine large volumes of rock in three dimensions. Characterization of potential sites requires geophysicists to alter their usual mode of thinking: no longer are anomalies being sought, as in mineral exploration, but rather their absence. Thus the size of features that might go undetected by a particular method take on new significance. Legal and regulatory considerations that stem from this different outlook, most notably the requirements of quality assurance (necessary for any data used in support of a repository license application), are forcing changes in the manner in which geophysicists collect and document their data. -Authors

  13. Dynamic use of geoscience information to develop scientific understanding for a nuclear waste repository

    SciTech Connect

    Cook, N.G.W.; Tsang, C.F.

    1990-01-01

    The development and safety evaluation of a nuclear waste geologic repository require a proper scientific understanding of the site response. Such scientific understanding depends on information from a number of geoscience disciplines, including geology, geophysics, geochemistry, geomechanics and hydrogeology. The information comes in four stages: (1) general regional survey data base, (2) surface-based testing, (3) exploratory shaft testing, and (4) repository construction and evaluation. A discussion is given on the dynamic use of the information through the different stages. We point out the need for abstracting, deriving and updating a quantitative spatial and process model (QSPM) to develop a scientific understanding of site responses as a crucial element in the dynamic procedure. 2 figs.

  14. Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada

    USGS Publications Warehouse

    Whitney, John W.; O'Leary, Dennis W.

    1993-01-01

    Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada, is needed to assess seismic and possible volcanic hazards that could affect the site during the preclosure (next 100 years) and the behavior of the hydrologic system during the postclosure (the following 10,000 years) periods. Tectonic characterization is based on assembling mapped geological structures in their chronological order of development and activity, and interpreting their dynamic interrelationships. Addition of mechanistic models and kinematic explanations for the identified tectonic processes provides one or more tectonic models having predictive power. Proper evaluation and application of tectonic models can aid in seismic design and help anticipate probable occurrence of future geologic events of significance to the repository and its design.

  15. Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada

    SciTech Connect

    Whitney, J.W.; O`Leary, D.W.

    1993-09-01

    Tectonic characterization of a potential high-level nuclear waste repository at Yucca Mountain, Nevada, is needed to assess seismic and possible volcanic hazards that could affect the site during the preclosure (next 100 years) and the behavior of the hydrologic system during the postclosure (the following 10,000 years) periods. Tectonic characterization is based on assembling mapped geological structures in their chronological order of development and activity, and interpreting their dynamic interrelationships. Addition of mechanistic models and kinematic explanations for the identified tectonic processes provides one or more tectonic models having predictive power. Proper evaluation and application of tectonic models can aid in seismic design and help anticipate probable occurrence of future geologic events of significance to the repository and its design.

  16. Microbial effects on the radionuclide transport in a deep nuclear waste repository

    SciTech Connect

    Spor, H.; Trescinski, M.; Libert, M.F.

    1993-12-31

    This study deals with the effects of microorganisms on the transport of radionuclides under deep nuclear-waste disposal conditions. Metabolism of a cellulolytic microorganism is studied. Cellulose, as a carbon source, is representative of nuclear waste. A pilot device allows the study of the general effect of microrganisms. Bioleaching of radionuclides by a fungal culture is performed on columns of clay and cement used as engineered barriers. Cesium and Uranium had been incorporated into matrices prior to the tests. Operating conditions have been choosen according to realistic conditions of a deep repository. The production of organic acids by microorganisms is qualitatively and quantitatively determined. In addition, direct effects of microorganisms (biosorption, bioaccumulation) and indirect effects (complexing agents issued from the diodegradation of cellulose) on the transport and/or retardation of radionuclides are studied.

  17. Release and transport of gaseous C-14 from a nuclear waste repository in an unsaturated medium

    SciTech Connect

    Light, W.B.; Zwahlen, E.D.; Pigford, T.H.; Chambre, P.L.; Lee, W.W.L.

    1990-11-01

    The potential nuclear waste repository at Yucca Mountain is to be in partially saturated rock. Released radioactive gases such as {sup 14}CO{sub 2} could have a direct pathway to the biosphere. We study the release of {sup 14}C released as {sup 14}CO{sub 2} from partly failed nuclear waste containers by analyzing the flow of gas into and out of a container. We analyze the transport of released {sup 14}CO{sub 2} in an unsaturated, fractured, porous medium with gas-phase advection and dispersion. We calculate the inhalation dose to a maximally exposed individual above ground, based on some conservative assumptions about release from containers. For the assumed parameter values, a simple atmospheric diffusion model gives very small doses when compared to background radiation doses. 12 refs., 4 figs., 1 tab.

  18. Selection criteria for container materials at the proposed Yucca Mountain high level nuclear waste repository

    SciTech Connect

    Halsey, W.G.

    1989-11-01

    A geological repository has been proposed for the permanent disposal of the nation`s high level nuclear waste at Yucca Mountain in the Nevada desert. The containers for this waste must remain intact for the unprecedented service lifetime of 1000 years. A combination of engineering, regulatory, and licensing requirements complicate the container material selection. In parallel to gathering information regarding the Yucca Mountain service environment and material performance data, a set of selection criteria have been established which compare candidate materials to the performance requirements, and allow a quantitative comparison of candidates. These criteria assign relative weighting to varied topic areas such as mechanical properties, corrosion resistance, fabricability, and cost. Considering the long service life of the waste containers, it is not surprising that the corrosion behavior of the material is a dominant factor. 7 refs.

  19. Dynamic analysis and design considerations for high-level nuclear waste repositories

    SciTech Connect

    Hossain, Q.A.

    1993-09-01

    These proceedings are arranged into six broad categories: general overview of analysis and design; characterization of faulting; characterization of design ground vibratory ground motion; considerations for underground facilities; considerations for surface facilities; and guidelines for instrumentation and monitoring. Discussions are given on the relative merits and inadequacies of state-of-the-art design/analysis practices and methodologies in the seismic and dynamic analysis and design field in relation to high-level nuclear waste repositories. All papers have been processed for inclusion on the data base.

  20. Costs and impacts of transporting nuclear waste to candidate repository sites

    SciTech Connect

    McSweeney, T.I.; Peterson, R.W.; Gupta, R.

    1983-12-31

    In this paper, a status report on the current estimated costs and impacts of transporting high-level nuclear wastes to candidate disposal sites is given. Impacts in this analysis are measured in terms of risk to public health and safety. Since it is difficult to project the status of the nuclear industry to the time of repository operation - 20 to 50 years in the future - particular emphasis in the paper is placed on the evaluation of uncertainties. The first part of this paper briefly describes the characteristics of the waste that must be transported to a high-level waste disposal site. This discussion is followed by a section describing the characteristics of the waste transport system. Subsequent sections describe the costs and risk assessments of waste transport. Finally, in a concluding section, the effect of the uncertainties in the definition of the waste disposal system on cost and risk levels is evaluated. This last section also provides some perspectives on the magnitude of the cost and risk levels relative to other comparable costs and risks generally encountered. 13 references, 2 figures, 16 tables.

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

    NASA Astrophysics Data System (ADS)

    Koudelka, Tomáš; Kruis, Jaroslav

    2016-06-01

    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.

  2. Modeling Hydrogen-Induced Cracking of Titanium Alloys in Nuclear Waste Repository Environments

    SciTech Connect

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-09-08

    This paper reviews the current understanding of hydrogen-induced cracking (HIC) of Ti Grade 7 and other relevant titanium alloys within the context of the current waste package design for the repository environmental conditions anticipated within the Yucca Mountain repository. The review concentrates on corrosion processes possible in the aqueous environments expected within this site. A brief background discussion of the relevant properties of titanium alloys, the hydrogen absorption process, and the properties of passive film on titanium alloys is presented as the basis for the subsequent discussion of model developments. The key corrosion processes that could occur are addressed individually. Subsequently, the expected corrosion performance of these alloys under the specific environmental conditions anticipated at Yucca Mountain is considered. It can be concluded that, based on the conservative modeling approaches adopted, hydrogen-induced cracking of titanium alloys will not occur under nuclear waste repository conditions since there will not be sufficient hydrogen in the alloy after 10,000 years of emplacement.

  3. TEMP: A finite line heat transfer code for geologic repositories for nuclear waste

    SciTech Connect

    Wurm, K.J.; Bloom, S.G.; Atterbury, W.G.; Hetteberg, J.R.

    1987-10-01

    TEMP is a FORTRAN computer code for calculating temperatures in a geologic repository for nuclear waste. It will calculate the incremental temperature contributed by a single heat source, by an infinite array of heat sources, or by heat sources geometrically arranged in a finite array. In the finite array geometry, different types of heat sources can be placed in different regions at different times to more closely approximate the emplacement of waste in a repository. TEMP uses a semi-analytical technique for solving the equation for a heat producing finite length line source in an infinite and isotropic medium. Temperature contributions from individual heat sources are superimposed to determine the temperature at a specific location and time in a repository of multiple heat sources. Thermal conductivity of the geologic medium can be a function of temperature, and, when it is, an approximation is made for the temperature dependence of thermal diffusivity. This report derives the equations solved by TEMP and documents its accuracy by comparing its results to known analytical solutions and to the finite-difference and finite-element heat transfer codes HEATING5, HEATING6, THAC-SIP-3D, SPECTROM-41, and STEALTH-2D. The temperature results from TEMP are shown to be very accurate when compared to the analytical solutions and to the results from the finite-difference and finite-element codes. 8 refs., 97 figs., 39 tabs.

  4. Feasibility assessment of copper-base waste package container materials in nuclear waste repositories sited in basalt and tuff

    SciTech Connect

    Gause, E.P.; Abraham, N.

    1987-12-31

    In early 1984, the United States Department of Energy Office of Civilian Radioactive Waste Management (DOE-OCRWM) established a two-year program (FY 1985 and FY 1986) to evaluate the use of copper and copper alloys in basalt and tuff repository environments in accordance with Congressional directive. The Basalt Waste Isolation Project (BWIP) and the Nevada Nuclear Waste Storage Investigation (NNWSI) Project concluded that copper-base materials are feasible as candidate container materials in a repository sited in a basalt or tuff environment. The feasibility of using copper materials in containers was qualitatively assessed using the following criteria: 1) container design and development; 2) preclosure safety (e.g., fabrication or emplacement risks); 3) repository interfaces (e.g., handling of containers); 4) retrievability considerations; 5) containment (mainly corrosion considerations); 6) radionuclide release (container/waste interactions); and 7) cost and availability. Weighting factors were not used and no comparison to other candidate disposal container materials was made. This paper details the results of testing, literature reviews, and evaluations that were performed for each of the seven criteria on each of the three conceptual container designs. The designs were as follows: A thick-walled Cupronickel 90-10 pressure vessel (BWIP); a copper monolith made by the HIP (hot isostatic pressing) process (BWIP); and a thin-walled aluminum bronze or Cupronickel 70-30 pressure vessel (NNWSI Project). A brief discussion of future plans to evaluate copper-base materials is presented for the BWIP and NNWSI Project.

  5. Corrosion-induced gas generation in a nuclear waste repository: Reactive geochemistry and multiphase flow effect

    SciTech Connect

    Xu, T.; Senger, R.; Finsterle, S.

    2008-10-15

    Corrosion of steel canisters, stored in a repository for spent fuel and high-level nuclear wastes, leads to the generation and accumulation of hydrogen gas in the backfilled emplacement tunnels, which may significantly affect long-term repository safety. Previous studies used H{sub 2} generation rates based on the volume of the waste or canister material and the stoichiometry of the corrosion reaction. However, iron corrosion and H{sub 2} generation rates vary with time, depending on factors such as amount of iron, water availability, water contact area, and aqueous and solid chemistry. To account for these factors and feedback mechanisms, we developed a chemistry model related to iron corrosion, coupled with two-phase (liquid and gas) flow phenomena that are driven by gas-pressure buildup associated with H{sub 2} generation and water consumption. Results indicate that by dynamically calculating H{sub 2} generation rates based on a simple model of corrosion chemistry, and by coupling this corrosion reaction with two-phase flow processes, the degree and extent of gas pressure buildup could be much smaller compared to a model that neglects the coupling between flow and reactive transport mechanisms. By considering the feedback of corrosion chemistry, the gas pressure increases initially at the canister, but later decreases and eventually returns to a stabilized pressure that is slightly higher than the background pressure. The current study focuses on corrosion under anaerobic conditions for which the coupled hydrogeochemical model was used to examine the role of selected physical parameters on the H{sub 2} gas generation and corresponding pressure buildup in a nuclear waste repository. The developed model can be applied to evaluate the effect of water and mineral chemistry of the buffer and host rock on the corrosion reaction for future site-specific studies.

  6. Preclosure analysis of conceptual waste package designs for a nuclear waste repository in tuff

    SciTech Connect

    O`Neal, W.C.; Gregg, D.W.; Hockman, J.N.; Russell, E.W.; Stein, W.

    1984-11-01

    This report discusses the selection and analysis of conceptual waste package developed by the Nevada Nuclear Waste Storage Investigations (NNWSI) project for possible disposal of high-level nuclear waste at a candidate site at Yucca Mountain, Nevada. The design requirements that the waste package must conform to are listed, as are several desirable design considerations. Illustrations of the reference and alternative designs are shown. Four austenitic stainless steels (316L SS, 321 SS, 304L SS and Incoloy 825 high nickel alloy) have been selected for candidate canister/overpack materials, and 1020 carbon steel has been selected as the reference metal for the borehole liners. A summary of the results of technical and ecnonmic analyses supporting the selection of the conceptual waste package designs is included. Postclosure containment and release rates are not analyzed in this report.

  7. Expected environments in high-level nuclear waste and spent fuel repositories in salt

    SciTech Connect

    Claiborne, H.C.; Rickertsen, L.D., Graham, R.F.

    1980-08-01

    The purpose of this report is to describe the expected environments associated with high-level waste (HLW) and spent fuel (SF) repositories in salt formations. These environments include the thermal, fluid, pressure, brine chemistry, and radiation fields predicted for the repository conceptual designs. In this study, it is assumed that the repository will be a room and pillar mine in a rock-salt formation, with the disposal horizon located approx. 2000 ft (610 m) below the surface of the earth. Canistered waste packages containing HLW in a solid matrix or SF elements are emplaced in vertical holes in the floor of the rooms. The emplacement holes are backfilled with crushed salt or other material and sealed at some later time. Sensitivity studies are presented to show the effect of changing the areal heat load, the canister heat load, the barrier material and thickness, ventilation of the storage room, and adding a second row to the emplacement configuration. The calculated thermal environment is used as input for brine migration calculations. The vapor and gas pressure will gradually attain the lithostatic pressure in a sealed repository. In the unlikely event that an emplacement hole will become sealed in relatively early years, the vapor space pressure was calculated for three scenarios (i.e., no hole closure - no backfill, no hole closure - backfill, and hole closure - no backfill). It was assumed that the gas in the system consisted of air and water vapor in equilibrium with brine. A computer code (REPRESS) was developed assuming that these changes occur slowly (equilibrium conditions). The brine chemical environment is outlined in terms of brine chemistry, corrosion, and compositions. The nuclear radiation environment emphasized in this report is the stored energy that can be released as a result of radiation damage or crystal dislocations within crystal lattices.

  8. Development of permeable reactive barriers to prevent radionuclide migration from the nuclear waste repositories

    SciTech Connect

    Zakharova, E.; Kalmykov, S.; Batuk, O.; Kazakovskaya, T.; Shapovalov, V.; Haire, M.J.

    2007-07-01

    This paper is focused on three possible materials for permeable reactive barriers (PRB): 1) depleted uranium oxide that is accumulated as a residual product of the natural uranium enrichment process, 2) zero-valent iron and, 3) the composite material based on montmorillonite clay modified with different anion exchangers. The main aim of permeable reactive barriers is to prevent release of radionuclides emerging from a repository waste package containing spent nuclear fuel to outside the control area of the nuclear waste repository sites. The most experimentally developed material is depleted uranium oxide. It can be used both as a component of radiation shielding and as an absorbent for migrating long-lived radionuclides (especially {sup 237}Np and {sup 99}Tc). Experiments demonstrate the high sorption properties of depleted uranium oxide towards Np and Tc both from deionized water and from solution that simulates Yucca Mountain. Zero-valent iron, and the composite based on montmorillonite clay, also seem to be very promising to use in a PRB. Nano-particles of zero-valent iron with high surface will reduce high valency Np and Tc to the tetravalent state and thus immobilize them due to the extremely low solubility of corresponding hydroxides. The composite based on montmorillonite clay modified with different anion exchangers will possess high sorption affinity towards anionic and cationic species. (authors)

  9. Optimizing nuclear waste repository development by implementing experimental data on radiolysis

    SciTech Connect

    Paviet-Hartmann, Patricia; Hartmann, Thomas

    2007-07-01

    In a conceivable scenario of proposed geological salt repositories for nuclear waste within the time frame of 10,000 to 100,000 years being considered for performance assessment, groundwater intrusion leads to inundation of the repository and the formation of chloride-based brines. These brines will be exposed to {alpha}- radiation emitted by released transuranic waste constituents, mainly Pu, U, Am, and Np. In the absence of bromide, {alpha}-radiolysis causes the formation of radiolytic species such as hypochlorite (OCl{sup -}) and hypochlorous acid (HOCl). Natural brines contain at least traces of bromide ions to influence radiation chemical effects in the near-field of the nuclear disposal site. We are presenting new results on the irradiation-induced formation of two bromide species: ClBr{sub 2}{sup -} and Br{sub 3}{sup -} observed at 247 nm and 266 nm by spectrophotometry after irradiating synthetic NaCl based brine solutions, containing 1.13 g of NaBr, by 5.2 MeV He{sup ++} ions by using a 3 MV Tandem accelerator. The measured formation rates as G values (100 eV yields) are G(Br{sub 2}Cl{sup -}) = 3.51*10{sup -3} {+-} 0.04*10{sup -3} molecules per 100 eV, and G(Br{sub 3}{sup -}) = 2.67*10{sup -3} {+-} 0.04.10{sup -3} molecules per 100 eV radiation energy. (authors)

  10. Selection of candidate canister materials for high-level nuclear waste containment in a tuff repository

    SciTech Connect

    McCright, R.D.; Weiss, H.; Juhas, M.C.; Logan, R.W.

    1983-11-01

    A repository located at Yucca Mountain at the Nevada Test Site is a potential site for permanent geological disposal of high-level nuclear waste. The repository can be located in a horizon in welded tuff, a volcanic rock, which is above the static water level at this site. The environmental conditions in this unsaturated zone are expected to be air and water vapor dominated for much of the containment period. Type 304L stainless steel is the reference material for fabricating canisters to contain the solid high-level wastes. Alternative stainless alloys are considered because of possible susceptibility of 304L to localized and stress forms of corrosion. For the reprocessed glass wastes, the canisters serve as the recipient for pouring the glass with the result that a sensitized microstructure may develop because of the times at elevated temperatures. Corrosion testing of the reference and alternative materials has begun in tuff-conditioned water and steam environments. 21 references, 8 figures, 8 tables.

  11. Modelling groundwater contamination above a nuclear waste repository at Gorleben, Germany

    NASA Astrophysics Data System (ADS)

    Schwartz, Michael O.

    2012-05-01

    The candidate repository for high-level nuclear waste in the Gorleben salt dome, Germany, is expected to host 8,550 tonnes of uranium in burnt fuel. It has been proposed that 5,440 waste containers be deposited at a depth of about 800 m. There is 260-280 m of siliciclastic cover sediments above the proposed repository. The potential groundwater contamination in the siliciclastic aquifer is simulated with the TOUGHREACT and TOUGH2-MP codes for a three-dimensional model with 290,435 elements. Two deterministic cases are simulated. The single-phase case considers the transport of radionuclides in the liquid phase only. The two-phase case accounts for hydrogen gas generated by the corrosion of waste containers and release of gaseous C-14. The gas release via a backfilled shaft is assumed to be steady (non-explosive). The simulation period is 2,000,000 years for the single-phase case and 7,000 years for the two-phase case. Only the radioactive dose in the two-phase case is higher than the regulatory limit (0.1 mSv/a).

  12. Thermodynamic coupling of heat and matter flows in near-field regions of nuclear waste repositories

    SciTech Connect

    Carnahan, C.L.

    1983-11-01

    In near-field regions of nuclear waste repositories, thermodynamically coupled flows of heat and matter can occur in addition to the independent flows in the presence of gradients of temperature, hydraulic potential, and composition. The following coupled effects can occur: thermal osmosis, thermal diffusion, chemical osmosis, thermal filtration, diffusion thermal effect, ultrafiltration, and coupled diffusion. Flows of heat and matter associated with these effects can modify the flows predictable from the direct effects, which are expressed by Fourier's law, Darcy's law, and Fick's law. The coupled effects can be treated quantitatively together with the direct effects by the methods of the thermodynamics of irreversible processes. The extent of departure of fully coupled flows from predictions based only on consideration of direct effects depends on the strengths of the gradients driving flows, and may be significant at early times in backfills and in near-field geologic environments of repositories. Approximate calculations using data from the literature and reasonable assumptions of repository conditions indicate that thermal-osmotic and chemical-osmotic flows of water in semipermeable backfills may exceed Darcian flows by two to three orders of magnitude, while flows of solutes may be reduced greatly by ultrafiltration and chemical osmosis, relative to the flows predicted by advection and diffusion alone. In permeable materials, thermal diffusion may contribute to solute flows to a smaller, but still significant, extent.

  13. Role of natural analogs in performance assessment of nuclear waste repositories

    SciTech Connect

    Sagar, B.; Wittmeyer, G.W.

    1995-09-01

    Mathematical models of the flow of water and transport of radionuclides in porous media will be used to assess the ability of deep geologic repositories to safely contain nuclear waste. These models must, in some sense, be validated to ensure that they adequately describe the physical processes occurring within the repository and its geologic setting. Inasmuch as the spatial and temporal scales over which these models must be applied in performance assessment are very large, validation of these models against laboratory and small-scale field experiments may be considered inadequate. Natural analogs may provide validation data that are representative of physico-chemical processes that occur over spatial and temporal scales as large or larger than those relevant to repository design. The authors discuss the manner in which natural analog data may be used to increase confidence in performance assessment models and conclude that, while these data may be suitable for testing the basic laws governing flow and transport, there is insufficient control of boundary and initial conditions and forcing functions to permit quantitative validation of complex, spatially distributed flow and transport models. The authors also express their opinion that, for collecting adequate data from natural analogs, resources will have to be devoted to them that are much larger than are devoted to them at present.

  14. Functions of an engineered barrier system for a nuclear waste repository in basalt

    SciTech Connect

    Coons, W.E.; Moore, E.L.; Smith, M.J.; Kaser, J.D.

    1980-01-01

    Defined in this document are the functions of components selected for an engineered barrier system for a nuclear waste repository in basalt. The definitions provide a focal point for barrier material research and development by delineating the purpose and operative lifetime of each component of the engineered system. A five-component system (comprised of waste form, canister, buffer, overpack, and tailored backfill) is discussed in terms of effective operation throughout the course of repository history, recognizing that the emplacement environment changes with time. While components of the system are mutually supporting, redundancy is provided by subsystems of physical and chemical barriers which act in concert with the geology to provide a formidable barrier to transport of hazardous materials to the biosphere. The operating philosophy of the conceptual engineered barrier system is clarified by examples pertinent to storage in basalt, and a technical approach to barrier design and material selection is proposed. A method for system validation and qualification is also included which considers performance criteria proposed by external agencies in conjunction with site-specific models and risk assessment to define acceptable levels of system performance.

  15. Chemical variability of zeolites at a potential nuclear waste repository, Yucca Mountain, Nevada

    SciTech Connect

    Broxton, D.E.

    1985-12-31

    The compositions of clinoptilolites and their host tuffs have been examined by electron microprobe and x-ray fluorescence, respectively, to determine their variability at a potential nuclear waste repository, Yucca Mountain, Nevada. Because of their sorptive properties, these zeolites could provide important geologic barriers to radionuclide migration. Variations in clinoptilolite composition can strongly affect the mineral`s thermal and ion-exchange properties, thus influencing its behavior in the repository environment. Clinoptilolites and heulandites closest to the proposed repository have calcium-rich compositions (60 to 90 mol. % Ca) and silica-to-aluminum ratios that concentrate between 4.0 and 4.6. In contrast, clinoptilolites and their host tuffs deeper in the volcanic sequence have highly variable compositions that vary vertically and laterally. Deeper-occurring clinoptilolites in the eastern part of Yucca Mountain are characterized by calcic-potassic compositions and tend to become more calcium-rich with depth. Clinoptilolites at equivalent stratigraphic levels on the western side of Yucca Mountain have sodic-potassic compositions and tend to become more sodium-rich with depth. Despite their differences in exchangeable cation compositions these two deeper-occurring compositional suites have similar silica-to-aluminum ratios, concentrating between 4.4 and 5.0. The chemical variability of clinoptilolites and their host tuffs at Yucca Mountain suggest that their physical and chemical properties will also vary. Compositionally-dependent clinoptilolite properties important for repository performance assessment include expansion/contraction behavior, hydration/dehydration behavior, and ion-exchange properties.

  16. Overweight truck shipments to nuclear waste repositories: legal, political, administrative and operational considerations

    SciTech Connect

    Not Available

    1986-03-01

    This report, prepared for the Chicago Operations Office and the Office of Civilian Radioactive Waste Management (OCRWM) of the US Department of Energy (DOE), identifies and analyzes legal, political, administrative, and operational issues that could affect an OCRWM decision to develop an overweight truck cask fleet for the commercial nuclear waste repository program. It also provides information required by DOE on vehicle size-and-weight administration and regulation, pertinent to nuclear waste shipments. Current legal-weight truck casks have a payload of one pressurized-water reactor spent fuel element or two boiling-water reactor spent fuel elements (1 PWR/2 BWR). For the requirements of the 1960s and 1970s, casks were designed with massive shielding to accommodate 6-month-old spent fuel; the gross vehicle weight was limited to 73,280 pounds. Spent fuel to be moved in the 1990s will have aged five years or more. Gross vehicle weight limitation for the Interstate highway system has been increased to 80,000 pounds. These changes allow the design of 25-ton legal-weight truck casks with payloads of 2 PWR/5 BWR. These changes may also allow the development of a 40-ton overweight truck cask with a payload of 4 PWR/10 BWR. Such overweight casks will result in significantly fewer highway shipments compared with legal-weight casks, with potential reductions in transport-related repository risks and costs. These advantages must be weighed against a number of institutional issues surrounding such overweight shipments before a substantial commitment is made to develop an overweight truck cask fleet. This report discusses these issues in detail and provides recommended actions to DOE.

  17. Long-Term Environmental Monitoring of an Operating Deep Geologic Nuclear Waste Repository

    SciTech Connect

    Conca, J.; Kirchner, Th.; Monk, J.; Sage, S.

    2008-07-01

    In the present energy dilemma in which we find ourselves, the magnitude of humanity's energy needs requires that we embrace a multitude of various energy sources and applications. Nuclear energy must be a major portion of the distribution. One often-cited strategic hurdle to the commercial production of nuclear energy is the apparent lack of an acceptable nuclear waste repository. This issue has been quietly addressed at the U. S. Department of Energy (DOE) Waste Isolation Pilot Plant (WIPP; see http://www.wipp.energy.gov), the closest population center of significant size being Carlsbad, New Mexico. WIPP has been operating for about nine years, disposing of over 250,000 drum-equivalents of nuclear waste. From the standpoint of addressing operational and environmental risk, as well as public fear, WIPP has had extensive human health and environmental monitoring. The Carlsbad Environmental Monitoring and Research Center is in the Institute for Energy and the Environment, in the College of Engineering at New Mexico State University. Located in Carlsbad, NM, CEMRC has been the independent monitoring facility for the area around WIPP from 1993 to the present, i.e., from six years before disposal operations began to nine years of waste disposal operations (www.cemcr.org). Based on the radiological analyses of monitoring samples completed to date for area residents and site workers, and for selected aerosols, soils, sediments, drinking water and surface waters, there is no evidence of increases in radiological contaminants in the region of WIPP that could be attributed to releases from WIPP. Levels of radiological and non-radiological analytes measured since operations began in 1999 have been within the range of baseline levels measured previously, and are within the ranges measured by other entities at the State and local levels since well before disposal phase operations began in 1999. (authors)

  18. Sub-Seabed Repository for Nuclear Waste - a Strategic Alternative - 13102

    SciTech Connect

    McAllister, Keith R.

    2013-07-01

    It was recognized at the outset of nuclear power generation in the 1950's that the waste products would require isolation away from humans for periods in excess of 10,000 years. After years studying alternatives, the DOE recommended pursuing the development of a SNF/HLW disposal facility within Yucca Mountain in the desert of Nevada. That recommendation became law with passage of the NWPAA, effectively stopping development of other approaches to the waste problem. In the face of political resistance from the state of Nevada, the 2010 decision to withdraw the license application for the geologic repository at Yucca Mountain has delayed further the most mature option for safe, long-term disposal of SNF and HLW. It is time to revisit an alternative option, sub-seabed disposal within the US Exclusive Economic Zone (EEZ), which would permanently sequester waste out of the biosphere, and out of the reach of saboteurs or terrorists. A proposal is made for a full scale pilot project to demonstrate burying radioactive waste in stable, deep ocean sediments. While much of the scientific work on pelagic clays has been done to develop a sub-seabed waste sequestration capability, this proposal introduces technology from non-traditional sources such as riser-less ocean drilling and the Navy's Sound Surveillance System. The political decisions affecting the issue will come down to site selection and a thorough understanding of comparative risks. The sub-seabed sequestration of nuclear waste has the potential to provide a robust solution to a critical problem for this clean and reliable energy source. (authors)

  19. Conceptualization of a hypothetical high-level nuclear waste repository site in unsaturated, fractured tuff

    SciTech Connect

    Parsons, A.M.; Olague, N.E.; Gallegos, D.P.

    1991-01-01

    Under the sponsorship of the US Nuclear Regulatory Commission (NRC), Sandia National Laboratories (SNL) is developing a performance assessment methodology for the analysis of long-term disposal and isolation of high-level nuclear wastes (HLW) in alternative geologic media. As part of this exercise, SNL created a conceptualization of ground-water flow and radionuclide transport in the far field of a hypothetical HLW repository site located in unsaturated, fractured tuff formations. This study provides a foundation for the development of conceptual mathematical, and numerical models to be used in this performance assessment methodology. This conceptualization is site specific in terms of geometry, the regional ground-water flow system, stratigraphy, and structure in that these are based on information from Yucca Mountain located on the Nevada Test Site. However, in terms of processes in unsaturated, fractured, porous media, the model is generic. This report also provides a review and evaluation of previously proposed conceptual models of unsaturated and saturated flow and solute transport. This report provides a qualitative description of a hypothetical HLW repository site in fractured tuff. However, evaluation of the current knowledge of flow and transport at Yucca Mountain does not yield a single conceptual model. Instead, multiple conceptual models are possible given the existing information.

  20. Perceived risk and benefit of nuclear waste repositories: four opinion clusters.

    PubMed

    Seidl, Roman; Moser, Corinne; Stauffacher, Michael; Krütli, Pius

    2013-06-01

    Local public resistance can block the site-selection process, construction, and operation of nuclear waste repositories. Social science has established that the perception of risks and benefits, trust in authorities, and opinion on nuclear energy play important roles in acceptance. In particular, risk and benefit evaluations seem critical for opinion formation. However, risks and benefits have rarely been studied independently and, most often, the focus has been on the two most salient groups of proponents and opponents. The aim of this exploratory study is to examine the often-neglected majority of people holding ambivalent or indifferent opinions. We used cluster analysis to examine the sample (N = 500, mailed survey in German-speaking Switzerland) in terms of patterns of risk and benefit perception. We reveal four significantly different and plausible clusters: one cluster with high-benefit ratings in favor of a repository and one cluster with high-risk ratings opposing it; a third cluster shows ambivalence, with high ratings on both risk and benefit scales and moderate opposition, whereas a fourth cluster seems indifferent, rating risks and benefits only moderately compared to the ambivalent cluster. We conclude that a closer look at the often neglected but considerable number of people with ambivalent or indifferent opinions is necessary. Although the extreme factions of the public will most probably not change their opinion, we do not yet know how the opinion of the ambivalent and indifferent clusters might develop over time. PMID:23020311

  1. Geochemically Homogeneous Tuffs Host the Potential Nuclear Waste Repository, Yucca Mountain, Nevada

    SciTech Connect

    Z.E. Peterman

    2001-07-13

    In evaluating a geological environment for the disposition of nuclear waste, the composition of the host rock is an important parameter in characterizing the natural system and its role as a barrier to migration of radionuclides. Emplacement drifts in a potential nuclear waste repository at Yucca Mountain, Nevada, would be constructed in the lower phenocryst-poor rhyolitic member ({approx}300 m thick) of the Topopah Spring Tuff, a felsic pyroclastic ash flow. The rhyolitic member, composed largely of microcrystalline quartz and alkali feldspar, contains localized secondary minerals including vapor-phase silica polymorphs and feldspar typically lining lithophysal cavities, and low-temperature calcite and opal in cavities and fractures. Chemical analyses of Topopah Spring Tuff samples from outcrops and from core obtained by surface-based drilling have shown that the phenocryst-poor rhyolite member at Yucca Mountain is remarkably uniform in composition both vertically and laterally. To verify this geochemical homogeneity in samples collected directly from the repository block where emplacement drifts would be constructed, major and trace elements were analyzed for core samples obtained from 20 systematically spaced drill holes in a drift constructed across the repository block. Means and standard deviations of selected oxides and elements in weight percent indicate geochemical uniformity among these samples: SiO{sub 2}, 76.29 {+-} 0.32; Al{sub 2}O{sub 3}, 12.55 {+-} 0.14; FeO, 0.13 {+-} 0.05; Fe{sub 2}O{sub 3}, 0.97 {+-} 0.07; MgO, 0.12 {+-} 0.02; CaO, 0.50 {+-} 0.03; Na{sub 2}O, 3.52 {+-} 0.11; K{sub 2}O, 4.83 {+-} 0.06; TiO{sub 2}, 0.109 {+-} 0.004; ZrO{sub 2}, 0.016 {+-} 0.001; MnO, 0.068 {+-} 0.008; Cl, 0.017 {+-} 0.004; F, 0.038 {+-} 0.008; and CO{sub 2}, 0.011 {+-} 0.003. Means and standard deviations of selected trace elements, in micrograms per gram, also indicate small compositional variability: Ba, 51 {+-} 12; Cs, 4.2 {+-} 0.3; Li, 25 {+-} 9; Pb, 27 {+-} 1

  2. Microstructural and mineralogical characterization of selected shales in support of nuclear waste repository studies

    SciTech Connect

    Lee, S.Y.; Hyder, L.K.; Alley, P.D.

    1988-01-01

    Five shales were examined as part of the Sedimentary Rock Program evaluation of this medium as a potential host for a US civilian nuclear waste repository. The units selected for characterization were the Chattanooga Shale from Fentress County, Tennessee; the Pierre Shale from Gregory County, South Dakota; the Green River Formation from Garfield County, Colorado; and the Nolichucky Shale and Pumpkin Valley Shale from Roane County, Tennessee. The micromorphology and structure of the shales were examined by petrographic, scanning electron, and high-resolution transmission electron microscopy. Chemical and mineralogical compositions were studied through the use of energy-dispersive x-ray, neutron activation, atomic absorption, thermal, and x-ray diffraction analysis techniques. 18 refs., 12 figs., 2 tabs.

  3. Coupled THMC models for bentonite in clay repository for nuclear waste

    NASA Astrophysics Data System (ADS)

    Zheng, L.; Rutqvist, J.; Birkholzer, J. T.; Li, Y.; Anguiano, H. H.

    2015-12-01

    Illitization, the transformation of smectite to illite, could compromise some beneficiary features of an engineered barrier system (EBS) that is composed primarily of bentonite and clay host rock. It is a major determining factor to establish the maximum design temperature of the repositories because it is believed that illitization could be greatly enhanced at temperatures higher than 100 oC and thus significantly lower the sorption and swelling capacity of bentonite and clay rock. However, existing experimental and modeling studies on the occurrence of illitization and related performance impacts are not conclusive, in part because the relevant couplings between the thermal, hydrological, chemical, and mechanical (THMC) processes have not been fully represented in the models. Here we present fully coupled THMC simulations of a generic nuclear waste repository in a clay formation with bentonite-backfilled EBS. Two scenarios were simulated for comparison: a case in which the temperature in the bentonite near the waste canister can reach about 200 oC and a case in which the temperature in the bentonite near the waste canister peaks at about 100 oC. The model simulations demonstrate that illitization is in general more significant at higher temperatures. We also compared the chemical changes and the resulting swelling stress change for two types of bentonite: Kunigel-VI and FEBEX bentonite. Higher temperatures also lead to much higher stress in the near field, caused by thermal pressurization and vapor pressure buildup in the EBS bentonite and clay host rock. Chemical changes lead to a reduction in swelling stress, which is more pronounced for Kunigel-VI bentonite than for FEBEX bentonite.

  4. MODELING OF THE GROUNDWATER TRANSPORT AROUND A DEEP BOREHOLE NUCLEAR WASTE REPOSITORY

    SciTech Connect

    N. Lubchenko; M. Rodríguez-Buño; E.A. Bates; R. Podgorney; E. Baglietto; J. Buongiorno; M.J. Driscoll

    2015-04-01

    The concept of disposal of high-level nuclear waste in deep boreholes drilled into crystalline bedrock is gaining renewed interest and consideration as a viable mined repository alternative. A large amount of work on conceptual borehole design and preliminary performance assessment has been performed by researchers at MIT, Sandia National Laboratories, SKB (Sweden), and others. Much of this work relied on analytical derivations or, in a few cases, on weakly coupled models of heat, water, and radionuclide transport in the rock. Detailed numerical models are necessary to account for the large heterogeneity of properties (e.g., permeability and salinity vs. depth, diffusion coefficients, etc.) that would be observed at potential borehole disposal sites. A derivation of the FALCON code (Fracturing And Liquid CONvection) was used for the thermal-hydrologic modeling. This code solves the transport equations in porous media in a fully coupled way. The application leverages the flexibility and strengths of the MOOSE framework, developed by Idaho National Laboratory. The current version simulates heat, fluid, and chemical species transport in a fully coupled way allowing the rigorous evaluation of candidate repository site performance. This paper mostly focuses on the modeling of a deep borehole repository under realistic conditions, including modeling of a finite array of boreholes surrounded by undisturbed rock. The decay heat generated by the canisters diffuses into the host rock. Water heating can potentially lead to convection on the scale of thousands of years after the emplacement of the fuel. This convection is tightly coupled to the transport of the dissolved salt, which can suppress convection and reduce the release of the radioactive materials to the aquifer. The purpose of this work has been to evaluate the importance of the borehole array spacing and find the conditions under which convective transport can be ruled out as a radionuclide transport mechanism

  5. Sorption of strontium on uranyl peroxide: implications for a high-level nuclear waste repository.

    PubMed

    Sureda, Rosa; Martínez-Lladó, Xavier; Rovira, Miquel; de Pablo, Joan; Casas, Ignasi; Giménez, Javier

    2010-09-15

    Strontium-90 is considered the most important radioactive isotope in the environment and one of the most frequently occurring radionuclides in groundwaters at nuclear facilities. The uranyl peroxide studtite (UO2O2 . 4H2O) has been observed to be formed in spent nuclear fuel leaching experiments and seems to have a relatively high sorption capacity for some radionuclides. In this work, the sorption of strontium onto studtite is studied as a function of time, strontium concentration in solution and pH. The main results obtained are (a) sorption is relatively fast although slower than for cesium; (b) strontium seems to be sorbed via a monolayer coverage of the studtite surface, (c) sorption has a strong dependence on ionic strength, is negligible at acidic pH, and increases at neutral to alkaline pH (almost 100% of the strontium in solution is sorbed above pH 10). These results point to uranium secondary solid phase formation on the spent nuclear fuel as an important mechanism for strontium retention in a high-level nuclear waste repository (HLNW). PMID:20638966

  6. Chemistry of diagenetically altered tuffs at a potential nuclear waste repository, Yucca Mountain, Nye County, Nevada

    SciTech Connect

    Broxton, D.E.; Warren, R.G.; Hagan, R.C.; Luedemann, G.

    1986-10-01

    The chemistry of diagenetically altered tuffs at a potential nuclear waste repository, Yucca Mountain, Nevada is described. These tuffs contain substantial amounts of zeolites that are highly sorptive of certain radionuclides. Because of their widespread distribution, the zeolitic tuffs could provide important barriers to radionuclide migration. Physical properties of these tuffs and of their constituent zeolites are influenced by their chemical compositions. This study defines the amount of chemical variability within diagenetically altered tuffs and within diagenetic minerals at Yucca Mountain. Zeolitic tuffs at Yucca Mountain formed by diagenetic alteration of rhyolitic vitric tuffs. Despite their similar starting compositions, these tuffs developed compositions that vary both vertically and laterally. Widespread chemical variations were the result of open-system chemical diagenesis in which chemical components of the tuffs were mobilized and redistributed by groundwaters. Alkalies, alkaline earths, and silica were the most mobile elements during diagenesis. The zeolitic tuffs can be divided into three compositional groups: (1) calcium- and magnesium-rich tuffs associated with relatively thin zones of alteration in the unsaturated zone; (2) tuffs in thick zones of alteration at and below the water table that grade laterally from sodic compositions on the western side of Yucca Mountain to calcic compositions on the eastern side; and (3) potassic tuffs at the north end of Yucca Mountain. Physical properties of tuffs and their consistuent zeolites at Yucca Mountain may be affected by variations in compositions. Properties important for assessment of repository performance include behavior and ion exchange.

  7. Bentonite alteration due to thermal-hydro-chemical processes during the early thermal period in a nuclear waste repository

    SciTech Connect

    Xu, T.; Senger, R.; Finsterle, S.

    2011-02-01

    After closure of an underground nuclear waste repository, the decay of radionuclides will raise temperature in the repository, and the bentonite buffer will resaturate by water inflow from the surrounding host rock. The perturbations from these thermal and hydrological processes are expected to dissipate within hundreds to a few thousand years. Here, we investigate coupled thermal-hydro-chemical processes and their effects on the short-term performance of a potential nuclear waste repository located in a clay formation. Using a simplified geometric configuration and abstracted hydraulic parameters of the clayey formation, we examine geochemical processes, coupled with thermo-hydrologic phenomena, and potential changes in porosity near the waste container during the early thermal period. The developed models were used for evaluating the mineral alterations and potential changes in porosity of the buffer, which can affect the repository performance. The results indicate that mineral alteration and associated changes in porosity induced by early thermal and hydrological processes are relatively small and are expected to not significantly affect flow and transport properties. Chlorite precipitation was obtained in all simulation cases. A maximum of one percent volume fraction of chlorite could be formed, whose process may reduce swelling and sorption capacity of bentonite clay, affecting the performance of the repository. llitisation process was not obtained from the present simulations.

  8. Geotechnical support and topical studies for nuclear waste geologic repositories: Annual report, fiscal year 1987

    SciTech Connect

    Not Available

    1988-01-01

    This multidisciplinary project was initiated in fiscal year 1986. It comprises 11 reports in two major interrelated tasks: The technical assistance part of the project includes reviewing the progress of the major projects in the DOE Office of Civilian Radioactive waste Management (OCRWM) Program and advising the Engineering and Geotechnology Division on significant technical issues facing each project; analyzing geotechnical data, reports, tests, surveys and plans for the different projects; reviewing and commenting on major technical reports and other program documents such as Site Characterization Plans (SCP) and Study Plans; and providing scientific and technical input at technical meetings. The topical studies activity comprises studies on scientific and technical ions and issues of significance to in-situ testing, test analysis methods, and site characterization of nuclear waste geologic repositories. The subjects of study were selected based on discussions with DOE staff. One minor topic is a preliminary consideration and planning exercise for postclosure monitoring studies. The major task, with subtasks involving various geoscience disciplines, is a study of the mechanical, hydraulic, geophysical and geochemical properties of fractures in geologic rock masses.

  9. SUMO, System performance assessment for a high-level nuclear waste repository: Mathematical models

    SciTech Connect

    Eslinger, P.W.; Miley, T.B.; Engel, D.W.; Chamberlain, P.J. II

    1992-09-01

    Following completion of the preliminary risk assessment of the potential Yucca Mountain Site by Pacific Northwest Laboratory (PNL) in 1988, the Office of Civilian Radioactive Waste Management (OCRWM) of the US Department of Energy (DOE) requested the Performance Assessment Scientific Support (PASS) Program at PNL to develop an integrated system model and computer code that provides performance and risk assessment analysis capabilities for a potential high-level nuclear waste repository. The system model that has been developed addresses the cumulative radionuclide release criteria established by the US Environmental Protection Agency (EPA) and estimates population risks in terms of dose to humans. The system model embodied in the SUMO (System Unsaturated Model) code will also allow benchmarking of other models being developed for the Yucca Mountain Project. The system model has three natural divisions: (1) source term, (2) far-field transport, and (3) dose to humans. This document gives a detailed description of the mathematics of each of these three divisions. Each of the governing equations employed is based on modeling assumptions that are widely accepted within the scientific community.

  10. Seismic Response of a Deep Underground Geologic Repository for Nuclear Waste at the Waste Isolation Pilot Plant in New Mexico

    SciTech Connect

    Sanchez, P.E.

    1998-11-02

    The Waste Isolation Pilot Plant (WIPP) is a deep underground nuclear waste repository certified by the U.S. Environmental Protection Agency ,(EPA) to store transuranic defense-related waste contaminated by small amounts of radioactive materials. Located at a depth of about 655 meters below the surface, the facility is sited in southeastern New Mexico, about 40 Department of Energy underground facilities, waste disposal. kilometers east of the city of Carlsbad, New Mexico. The U.S. (DOE) managed the design and construction of the surface and and remains responsible for operation and closure following The managing and operating contractor for the DOE at the WIPP, Westinghouse Electric Corporation, maintains two rechmiant seismic monitoring systems located at the surface and in the underground. This report discusses two earthquakes detected by the seismic monitoring system, one a duratior magnitude 5.0 (Md) event located approximately 60 km east-southeast of the facility, and another a body-wave magnitude 5.6 (rob) event that occurred approximately 260 kilometers to the south-southeast.

  11. Thermal calculations pertaining to a proposed Yucca Mountain nuclear waste repository

    SciTech Connect

    Johnson, G.L.; Montan, D.N.

    1990-02-01

    In support to the Yucca Mountain Project waste package and repository design efforts, LLNL conducted heat-transfer modeling of the volcanic tuff in the repository. The analyses quantify: the thermal response of a finite size, uniformly loaded repository where each panel of emplacement drifts contains the same type of heat source the response given a realistic waste stream inventory to show the effect of inter-panel variations; and the intra-panel response for various realistic distributions of sources within the panel. The calculations, using the PLUS family of computer codes, are based on a linear superposition, in time and in space, of the analytic solution of individual, constant output point sources located in an infinite, isotropic, and homogeneous medium with constant thermal properties. 8 refs., 22 figs., 3 tabs.

  12. RADIATION EFFECTS ON MATERIALS IN THE NEAR-FIELD OF NUCLEAR WASTE REPOSITORY

    EPA Science Inventory

    Successful, demonstrated containment of radionuclides in the near-field can greatly reduce the complexity of the performance assessment analysis of a geologic repository. The chemical durability of the waste form, the corrosion rate of the canister, and the physical and chemical ...

  13. Supplemental Performance Analyses for the Potential High-Level Nuclear Waste Repository at Yucca Mountain

    SciTech Connect

    Sevougian, S. D.; McNeish, J. A.; Coppersmith, K.; Jenni, K. E.; Rickertsen, L. D.; Swift, P. N.; Wilson, M. L.

    2002-02-26

    The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. To facilitate public review and comment, in May 2001 the DOE released the Yucca Mountain Science and Engineering Report (S&ER) (1), which presents technical information supporting the consideration of the possible site recommendation. The report summarizes the results of more than 20 years of scientific and engineering studies. Based on internal reviews of the S&ER and its key supporting references, the Total System Performance Assessment for the Site Recommendation (TSPA-SR) (2) and the Analysis Model Reports and Process Model Reports cited therein, the DOE has recently identified and performed several types of analyses to supplement the treatment of uncertainty in support of the consideration of a possible site recommendation. The results of these new analyses are summarized in the two-volume report entitled FY01 Supplemental Science and Performance Analysis (SSPA) (3,4). The information in this report is intended to supplement, not supplant, the information contained in the S&ER. The DOE recognizes that important uncertainties will always remain in any assessment of the performance of a potential repository over thousands of years (1). One part of the DOE approach to recognizing and managing these uncertainties is a commitment to continued testing and analysis and to the continued evaluation of the technical basis supporting the possible recommendation of the site, such as the analysis contained in the SSPA. The goals of the work described here are to provide insights into the implications of newly quantified uncertainties, updated science, and evaluations of lower operating temperatures on the performance of a potential Yucca Mountain repository and to increase confidence in the results of the TSPA described in the S

  14. Geology and hydrogeology of the proposed nuclear waste repository at Yucca Mountain, Nevada and the surrounding area

    SciTech Connect

    Mattson, S.R.; Broxton, D.E.; Crowe, B.M.; Buono, A.; Orkild, P.P.

    1989-07-01

    In late 1987 Congress issued an amendment to the Nuclear Waste Policy Act of 1982 which directed the characterization of Yucca Mountain, Nevada as the only remaining potential site for the Nation`s first underground high-level radioactive waste repository. The evaluation of a potential underground repository is guided and regulated by policy established by the Department of Energy (DOE), Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA), Department of Transportation (DOT), and the US Congress. The Yucca Mountain Project is the responsibility of the DOE. The purpose of this field trip is to introduce the present state of geologic and hydrologic knowledge concerning this site. This report describes the field trip. 108 refs., 6 figs., 1 tab.

  15. Review of geochemical measurement techniques for a nuclear waste repository in bedded salt

    SciTech Connect

    Knauss, K.G.; Steinborn, T.L.

    1980-05-22

    A broad, general review is presented of geochemical measurement techniques that can provide data necessary for site selection and repository effectiveness assessment for a radioactive waste repository in bedded salt. The available measurement techniques are organized according to the parameter measured. The list of geochemical parameters include all those measurable geochemical properties of a sample whole values determine the geochemical characteristics or behavior of the system. For each technique, remarks are made pertaining to the operating principles of the measurement instrument and the purpose for which the technique is used. Attention is drawn to areas where further research and development are needed.

  16. Brine: a computer program to compute brine migration adjacent to a nuclear waste canister in a salt repository

    SciTech Connect

    Duckworth, G.D.; Fuller, M.E.

    1980-06-10

    This report presents a mathematical model used to predict brine migration toward a nuclear waste canister in a bedded salt repository. The mathematical model is implemented in a computer program called BRINE. The program is written in FORTRAN and executes in the batch mode on a CDC 7600. A description of the program input requirements and output available is included. Samples of input and output are given.

  17. Radioactive waste isolation in salt: special advisory report on the status of the Office of Nuclear Waste Isolation's plans for repository performance assessment

    SciTech Connect

    Ditmars, J.D.; Walbridge, E.W.; Rote, D.M.; Harrison, W.; Herzenberg, C.L.

    1983-10-01

    Repository performance assessment is analysis that identifies events and processes that might affect a repository system for isolation of radioactive waste, examines their effects on barriers to waste migration, and estimates the probabilities of their occurrence and their consequences. In 1983 Battelle Memorial Institute's Office of Nuclear Waste Isolation (ONWI) prepared two plans - one for performance assessment for a waste repository in salt and one for verification and validation of performance assessment technology. At the request of the US Department of Energy's Salt Repository Project Office (SRPO), Argonne National Laboratory reviewed those plans and prepared this report to advise SRPO of specific areas where ONWI's plans for performance assessment might be improved. This report presents a framework for repository performance assessment that clearly identifies the relationships among the disposal problems, the processes underlying the problems, the tools for assessment (computer codes), and the data. In particular, the relationships among important processes and 26 model codes available to ONWI are indicated. A common suggestion for computer code verification and validation is the need for specific and unambiguous documentation of the results of performance assessment activities. A major portion of this report consists of status summaries of 27 model codes indicated as potentially useful by ONWI. The code summaries focus on three main areas: (1) the code's purpose, capabilities, and limitations; (2) status of the elements of documentation and review essential for code verification and validation; and (3) proposed application of the code for performance assessment of salt repository systems. 15 references, 6 figures, 4 tables.

  18. Results From an International Simulation Study on Couples Thermal, Hydrological, and Mechanical (THM) Processes Near Geological Nuclear Waste Repositories

    SciTech Connect

    J. Rutqvist; D. Barr; J.T. Birkholzer; M. Chijimatsu; O. Kolditz; Q. Liu; Y. Oda; W. Wang; C. Zhang

    2006-08-02

    As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the project, a good agreement was achieved between the research teams in calculating THM responses for both repository types, although some disagreement in hydrological responses is currently being resolved. In particular, good agreement in the basic thermal-mechanical responses was achieved for both repository types, even though some teams used relatively simplified thermal-elastic heat-conduction models that neglected complex near-field thermal-hydrological processes. The good agreement between the complex and simplified process models indicates that the basic thermal-mechanical responses can be predicted with a relatively high confidence level.

  19. Nuclear waste

    SciTech Connect

    Not Available

    1991-09-01

    Radioactive waste is mounting at U.S. nuclear power plants at a rate of more than 2,000 metric tons a year. Pursuant to statute and anticipating that a geologic repository would be available in 1998, the Department of Energy (DOE) entered into disposal contracts with nuclear utilities. Now, however, DOE does not expect the repository to be ready before 2010. For this reason, DOE does not want to develop a facility for monitored retrievable storage (MRS) by 1998. This book is concerned about how best to store the waste until a repository is available, congressional requesters asked GAO to review the alternatives of continued storage at utilities' reactor sites or transferring waste to an MRS facility, GAO assessed the likelihood of an MRSA facility operating by 1998, legal implications if DOE is not able to take delivery of wastes in 1998, propriety of using the Nuclear Waste Fund-from which DOE's waste program costs are paid-to pay utilities for on-site storage capacity added after 1998, ability of utilities to store their waste on-site until a repository is operating, and relative costs and safety of the two storage alternatives.

  20. Microbial impacts on the geochemistry evolution in a nuclear waste repository -Laboratory experiment of microbially mediated redox changes-

    NASA Astrophysics Data System (ADS)

    Nagaoka, T.

    2010-12-01

    It is important to investigate geochemical evolution around nuclear waste repositories, because geochemical conditions could affect radionuclide migration. Therefore, a laboratory jar experiment was conducted with subsurface sediments, in order to assess the response of the geochemical and microbial communities toward redox processes. The redox process was induced by exposure to air and discontinuation to sediment suspension, which simulated the process occurring during operation of nuclear waste repositories, i.e., tunnel excavation, transport of waste containers, and final backfilling. During the experiments, redox potential, dissolved oxygen, and pH in the suspension were measured, and the concentrations of dissolved ions concentration (e.g., NO3-, SO42- and organic acid), HCl-extractable iron, and also head space gasses (e.g., CO2, CH4) in the jar were analyzed. Moreover, microbial DNA was extracted from the suspension, and PCR-DGGE analysis was performed to analyze the response of microbial communities toward the geochemical changes. As a results, after discontinuation of air exposure with lactate amendment, redox potentials decreased from ca. +300 mV to -430 m V (vs. Ag/AgCl), and the sequential terminal electron-accepting process (TEAPs) was observed with the reactions of aerobic respiration, nitrate reduction, iron reduction, sulfate reduction, and methanogenesis. The related species of the microbes along with TEAPs, e.g., Pseudomonas sp. for nitrate reduction and Desulfovibrio sp. for sulfate reduction, was also detected. These results indicated that the microbial activities would affect the geochemical changes in nuclear repositories.

  1. Geological repository for nuclear high level waste in France from feasibility to design within a legal framework

    SciTech Connect

    Voizard, Patrice; Mayer, Stefan; Ouzounian, Gerald

    2007-07-01

    Over the past 15 years, the French program on deep geologic disposal of high level and long-lived radioactive waste has benefited from a clear legal framework as the result of the December 30, 1991 French Waste Act. To fulfil its obligations stipulated in this law, ANDRA has submitted the 'Dossier 2005 Argile' (clay) and 'Dossier 2005 Granite' to the French Government. The first of those reports presents a concept for the underground disposal of nuclear waste at a specific clay site and focuses on a feasibility study. Knowledge of the host rock characteristics is based on the investigations carried out at the Meuse/Haute Marne Underground Research Laboratory. The repository concept addresses various issues, the most important of which relates to the large amount of waste, the clay host rock and the reversibility requirement. This phase has ended upon review and evaluation of the 'Dossier 2005' made by different organisations including the National Review Board, the National Safety Authority and the NEA International Review Team. By passing the 'new', June 28, 2006 Planning Act on the sustainable management of radioactive materials and waste, the French parliament has further defined a clear legal framework for future work. This June 28 Planning Act thus sets a schedule and defines the objectives for the next phase of repository design in requesting the submission of a construction authorization application by 2015. The law calls for the repository program to be in a position to commission disposal installations by 2025. (authors)

  2. Materials Degradation Issues in the U.S. High-Level Nuclear Waste Repository

    SciTech Connect

    K.G. Mon; F. Hua

    2005-04-12

    This paper reviews the state-of-the-art understanding of the degradation processes by the Yucca Mountain Project (YMP) with focus on interaction between the in-drift environmental conditions and long-term materials degradation of waste packages and drip shields within the repository system during the first 10,000-years after repository closure. This paper provides an overview of the degradation of the waste packages and drip shields in the repository after permanent closure of the facility. The degradation modes discussed in this paper include aging and phase instability, dry oxidation, general and localized corrosion, stress corrosion cracking, and hydrogen induced cracking of Alloy 22 and titanium alloys. The effects of microbial activity and radiation on the degradation of Alloy 22 and titanium alloys are also discussed. Further, for titanium alloys, the effects of fluorides, bromides, and galvanic coupling to less noble metals are considered. It is concluded that the materials and design adopted will provide sufficient safety margins for at least 10,000-years after repository closure.

  3. The Use of Basalt, Basalt Fibers and Modified Graphite for Nuclear Waste Repository - 12150

    SciTech Connect

    Gulik, V.I.; Biland, A.B.

    2012-07-01

    New materials enhancing the isolation of radioactive waste and spent nuclear fuel are continuously being developed.. Our research suggests that basalt-based materials, including basalt roving chopped basalt fiber strands, basalt composite rebar and materials based on modified graphite, could be used for enhancing radioactive waste isolation during the storage and disposal phases and maintaining it during a significant portion of the post-closure phase. The basalt vitrification process of nuclear waste is a viable alternative to glass vitrification. Basalt roving, chopped basalt fiber strands and basalt composite rebars can significantly increase the strength and safety characteristics of nuclear waste and spent nuclear fuel storages. Materials based on MG are optimal waterproofing materials for nuclear waste containers. (authors)

  4. US nuclear repository in jeopardy

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2009-04-01

    Physicists have expressed uneasiness about the future of nuclear-waste storage in the US after President Barack Obama's administration proposed slashing funds for a long-planned repository at Yucca Mountain in Nevada. If approved by Congress, the cuts seem likely to spell the death knell of the project, which has been in the works since 1987 and has so far cost the government 9.5bn.

  5. Social impacts of hazardous and nuclear facilities and events: Implications for Nevada and the Yucca Mountain high-level nuclear waste repository; [Final report

    SciTech Connect

    Freudenburg, W.R.; Carter, L.F.; Willard, W.; Lodwick, D.G.; Hardert, R.A.; Levine, A.G.; Kroll-Smith, S.; Couch, S.R.; Edelstein, M.R.

    1992-05-01

    Social impacts of a nuclear waste repository are described. Various case studies are cited such as Rocky Flats Plant, the Feed Materials Production Center, and Love Canal. The social impacts of toxic contamination, mitigating environmental stigma and loss of trust are also discussed.

  6. A Natural Analogue for Thermal-Hydrological-Chemical Coupled Processes at the Proposed Nuclear Waste Repository at Yucca Mountain, Nevada

    SciTech Connect

    Bill Carey; Gordon Keating; Peter C. Lichtner

    1999-08-01

    Dike and sill complexes that intruded tuffaceous host rocks above the water table are suggested as natural analogues for thermal-hydrologic-chemical (THC) processes at the proposed nuclear waste repository at Yucca Mountain, Nevada. Scoping thermal-hydrologic calculations of temperature and saturation profiles surrounding a 30-50 m wide intrusion suggest that boiling conditions could be sustained at distances of tens of meters from the intrusion for several thousand years. This time scale for persistence of boiling is similar to that expected for the Yucca Mountain repository with moderate heat loading. By studying the hydrothermal alteration of the tuff host rocks surrounding the intrusions, insight and relevant data can be obtained that apply directly to the Yucca Mountain repository and can shed light on the extent and type of alteration that should be expected. Such data are needed to bound and constrain model parameters used in THC simulations of the effect of heat produced by the waste on the host rock and to provide a firm foundation for assessing overall repository performance. One example of a possible natural analogue for the repository is the Paiute Ridge intrusive complex located on the northeastern boundary of the Nevada Test Site, Nye County, Nevada. The complex consists of dikes and sills intruded into a partially saturated tuffaceous host rock that has stratigraphic sequences that correlate with those found at Yucca Mountain. The intrusions were emplaced at a depth of several hundred meters below the surface, similar to the depth of the proposed repository. The tuffaceous host rock surrounding the intrusions is hydrothermally altered to varying extents depending on the distance from the intrusions. The Paiute Ridge intrusive complex thus appears to be an ideal natural analogue of THC coupled processes associated with the Yucca Mountain repository. It could provide much needed physical and chemical data for understanding the influence of heat

  7. Micron-Scale MIC of Alloy 22 After Long Term Incubation in Saturated Nuclear Waste Repository Microcosms

    SciTech Connect

    Martin, S; Horn, J; Carrillo, C

    2003-10-29

    The effects of potential microbiologically influenced corrosion (MIC) on candidate packaging materials for nuclear waste containment are being assessed. Coupons of Alloy 22, the outer barrier candidate for waste packaging, were exposed to a simulated, saturated repository environment consisting of crushed rock from the repository site and a continual flow of simulated groundwater for periods up to five years. Coupons were incubated with YM tuff under both sterile and non-sterile conditions. Surfacial analysis of the biotically-incubated coupons show development of both submicron-sized pinholes and pores; these features were not present on either sterile or untreated control coupons. Quantification of these effects will help define the overall contribution of MIC to the integrity of the containment system over a period of 10,000 years.

  8. BIODOSE: a code for predicting the dose to man from radionuclides released from underground nuclear waste repositories

    SciTech Connect

    Bonner, N.A.; Ng, Y.C.

    1980-03-01

    The BIODOSE computer program simulates the environmental transport of radionuclides released to surface water and predicts the resulting dosage to humans. This report describes the program and discusses its use in the evaluation of nuclear waste repositories. The methods used to estimate dose are examined critically, and the most important parameters in each stage of the calculations are identified as an aid in planning for measurements in the field. Dose predictions from releases of nuclear waste to a large northwestern river (the baseline river) are presented to point out the nuclides, compartments and pathways that contribute most to the hazard as a function of waste storage time. Predictions for five other water systems are presented to identify the most important system parameters that determine the concentrations of individual nuclides in compartments and the resultant dose. The uncertainties in the biological parameters for dose prediction are identified, and changes in current values are suggested. Various ways of reporting dose estimates for radiological safety assessments are discussed. Additional work needed to improve the dose predictions from BIODOSE and specific areas and steps to improve our capabilities to assess the environmental transport of nuclides released from nuclear waste repositories and the resultant dose to man are suggested.

  9. Perceived risk, stigma, and potential economic impacts of a high-level nuclear waste repository in Nevada

    SciTech Connect

    Slovic, P.; Layman, M.; Kraus, N.N.; Chalmers, J.; Gesel, G.; Flynn, J.

    1989-07-01

    This paper describes a program of research designed to assess the potential impacts of a high-level nuclear waste repository at Yucca Mountain, Nevada, upon tourism, retirement and job-related migration, and business development in Las Vegas and the state. Adverse economic impacts may be expected to result from two related social processes. One has to do with perceptions of risk and socially amplified reactions to ``unfortunate events`` associated with the repository (major and minor accidents, discoveries of radiation releases, evidence of mismanagement, attempts to sabotage or disrupt the facility, etc.). The second process that may trigger significant adverse impacts is that of stigmatization. The conceptual underpinnings of risk perception, social amplification, and stigmatization are discussed in this paper and empirical data are presented to demonstrate how nuclear images associated with Las Vegas and the State of Nevada might trigger adverse effects on tourism, migration, and business development.

  10. Sweden picks site for waste repository

    NASA Astrophysics Data System (ADS)

    Stafford, Ned

    2009-07-01

    Nuclear power-plant operators in Sweden have selected a site where they can permanently store the country's spent nuclear fuel. The repository would be located 500 m below ground at Forsmark, roughly 200km north of Stockholm, which is already home to a nuclear power plant. The decision was taken after two decades of study by the Swedish Nuclear Fuel and Waste Management Company (SKB), which is owned by the country's nuclear firms.

  11. Nuclear waste repositories in salt mines: a new approach to safety assessment.

    PubMed

    Memmert, G

    1996-08-01

    The long-term safety of radioactive waste repositories in rock-salt mines in the deep underground benefits significantly from the barrier effect of overlying rocks. The concentrations of radioactive substances released from the repository and migrating in the aquifer up to the biosphere are greatly reduced during passage through these rocks. In former safety analyses of waste repositories this transport has generally been modelled as a combination of the involved phenomena, e.g. convection, dispersion, adsorption, etc. The data required for a numerical evaluation of the overall effect are obtained either as (conservative) estimates based on experience or are empirical, based mainly on laboratory experiments. The approach presented here is much simpler and entirely empirical, and therefore more transparent. It makes use of the fact that the groundwater in the overlying rocks always contains dissolved salt from the salt formation and carries it continuously into the receiving channels or the drainage system. The relation between the total amount of dissolved solids present in a certain subsurface catchment area and their steady-state concentration in the receiving channels is assumed to be equivalent to the relation between the given amount of radionuclides released from the repository and their concentration in the receiving channels, the latter leading to a certain radiation exposure of the population. Two versions of this approach are discussed: version (a) assumes a continuous stream of radionuclides released from the repository, and version (b) assumes a pulse release of radionuclides from the repository. A simple calculation using data from the Gorleben exploration leads to the inequality [equation: see text] where Cmax is the maximum radionuclide concentration (with respect to time) in the receiving channels and W (Bq) is the amount of radionuclides released from the respository in a very short time. Cmax obtained from (1), is supposed to be an upper limit of

  12. Science Is Important, but Politics Drives the Siting of Nuclear Waste Repositories

    NASA Astrophysics Data System (ADS)

    Shaw, George H.

    2014-02-01

    In 1982, I worked on the Nuclear Waste Policy Act as an AGU Congressional Science Fellow tasked with assisting a member of the House Energy and Commerce Committee. When I recently read the suggestion that clay-rich strata (shales) could be a viable medium for high-level nuclear waste (HLW) disposal [Neuzil, 2013], I could not help but remember the insights I gained more than 30 years ago from my time on the Hill.

  13. Prediction of Coupled Thermal, Hydrological and Chemical Processes at the Proposed Yucca Mountain Nuclear Waste Repository: An Integrated Approach

    SciTech Connect

    N. Spycher; E. Sonnenthal; T. Kneafsey; P. Dobson

    2003-10-17

    An integrated modeling approach was developed to investigate long-term coupled thermal, hydrological, and chemical (THC) processes that could take place around nuclear waste emplacement tunnels (drifts). The approach involves the development of process models, followed by numerical implementation and validation against field and laboratory experiments before conducting long-term predictive simulations. An outcome of this work was the refinement and validation of an existing reactive transport numerical code for applications specific to the geologic storage of nuclear waste. The model was applied to the case of the proposed high-level nuclear waste repository at Yucca Mountain, Nevada, to evaluate the chemistry of waters potentially seeping into drifts and the effect of water-rock interaction on long-term hydrological behavior around the repository. At liquid saturations significantly larger than residual, no extreme pH or salinity values were predicted. Mineral precipitation around drifts consists mainly of silica with minor calcite, trace zeolites and clays. The effect of mineral precipitation on flow depends largely on initial fracture porosity, and results in negligible to significant diversion of percolation around the drift. Further analyses of model uncertainty are under way to improve confidence in model results.

  14. The AEGIS technology demonstration for a nuclear waste repository in basalt. Assessment of effectiveness of geologic isolation systems

    NASA Astrophysics Data System (ADS)

    Dove, F. H.; Cole, C. R.; Foley, M. G.

    1982-09-01

    A technology demonstration of performance assessment techniques as applied to a nuclear waste repository in the Columbia Plateau Basalts was conducted. Hypothetical repository coordinates were selected for an acutal geographical setting on the Hanford Reservation in the state of Washington. Available information was used to establish the data base and initial hydrologic and geologic interpretations for this site-specific application. A simplified diagram of the AEGIS analyses is shown. Because an understanding of the dynamics of ground water flow is essential to the development of release scenarios and consequence analyses, a key step in the demonstration is the systems characterization contained in the conceputal model. Regional and local ground water movement patterns were defined with the aid of hydrologic computer models.

  15. AN EVALUATION OF HYDROGEN INDUCED CRACKING SUSCEPTIBILITY OF TITANIUM ALLOYS IN US HIGH-LEVEL NUCLEAR WASTE REPOSITORY ENVIRONMENTS

    SciTech Connect

    G. De; K. Mon; G. Gordon; D. Shoesmith; F. Hua

    2006-02-21

    This paper evaluates hydrogen-induced cracking (HIC) susceptibility of titanium alloys in environments anticipated in the Yucca Mountain nuclear waste repository with particular emphasis on the. effect of the oxide passive film on the hydrogen absorption process of titanium alloys being evaluated. The titanium alloys considered in this review include Ti 2, 5 , 7, 9, 11, 12, 16, 17, 18, 24 and 29. In general, the concentration of hydrogen in a titanium alloy can increase due to absorption of atomic hydrogen produced from passive general corrosion of that alloy or galvanic coupling of it to a less noble metal. It is concluded that under the exposure conditions anticipated in the Yucca Mountain repository, the HIC of titanium drip shield will not occur because there will not be sufficient hydrogen in the metal even after 10,000 years of emplacement. Due to the conservatisms adopted in the current evaluation, this assessment is considered very conservative.

  16. A comparative simulation study of coupled THM processes and their effect on fractured rock permeability around nuclear waste repositories

    SciTech Connect

    Rutqvist, Jonny; Barr, Deborah; Birkholzer, Jens T.; Fujisaki, Kiyoshi; Kolditz, Olf; Liu, Quan-Shen; Fujita, tomoo; Wang, Wenqing; Zhang, Cheng-Yuan

    2008-10-23

    This paper presents an international, multiple-code, simulation study of coupled thermal, hydrological, and mechanical (THM) processes and their effect on permeability and fluid flow in fractured rock around heated underground nuclear waste emplacement drifts. Simulations were conducted considering two types of repository settings: (a) open emplacement drifts in relatively shallow unsaturated volcanic rock, and (b) backfilled emplacement drifts in deeper saturated crystalline rock. The results showed that for the two assumed repository settings, the dominant mechanism of changes in rock permeability was thermal-mechanically-induced closure (reduced aperture) of vertical fractures, caused by thermal stress resulting from repository-wide heating of the rock mass. The magnitude of thermal-mechanically-induced changes in permeability was more substantial in the case of an emplacement drift located in a relatively shallow, low-stress environment where the rock is more compliant, allowing more substantial fracture closure during thermal stressing. However, in both of the assumed repository settings in this study, the thermal-mechanically-induced changes in permeability caused relatively small changes in the flow field, with most changes occurring in the vicinity of the emplacement drifts.

  17. Some Materials Degradation Issues in the U.S. High-Level Nuclear Waste Repository Study (The Yucca Mountain Project)

    SciTech Connect

    F. Hua; P. Pasupathi; N. Brown; K. Mon

    2005-09-19

    The safe disposal of radioactive waste requires that the waste be isolated from the environment until radioactive decay has reduced its toxicity to innocuous levels for plants, animals, and humans. All of the countries currently studying the options for disposing of high-level nuclear waste (HLW) have selected deep geologic formations to be the primary barrier for accomplishing this isolation. In U.S.A., the Nuclear Waste Policy Act of 1982 (as amended in 1987) designated Yucca Mountain in Nevada as the potential site to be characterized for high-level nuclear waste (HLW) disposal. Long-term containment of waste and subsequent slow release of radionuclides into the geosphere will rely on a system of natural and engineered barriers including a robust waste containment design. The waste package design consists of a highly corrosion resistant Ni-based Alloy 22 cylindrical barrier surrounding a Type 316 stainless steel inner structural vessel. The waste package is covered by a mailbox-shaped drip shield composed primarily of Ti Grade 7 with Ti Grade 24 structural support members. The U.S. Yucca Mountain Project has been studying and modeling the degradation issues of the relevant materials for some 20 years. This paper reviews the state-of-the-art understanding of the degradation processes based on the past 20 years studies on Yucca Mountain Project (YMP) materials degradation issues with focus on interaction between the in-drift environmental conditions and long-term materials degradation of waste packages and drip shields within the repository system during the 10,000 years regulatory period. This paper provides an overview of the current understanding of the likely degradation behavior of the waste package and drip shield in the repository after the permanent closure of the facility. The degradation scenario discussed in this paper include aging and phase instability, dry oxidation, general and localized corrosion, stress corrosion cracking and hydrogen induced

  18. Importance of transparency and traceability in building a safety case for high-level nuclear waste repositories.

    PubMed

    Mohanty, Sitakanta; Sagar, Budhi

    2002-02-01

    The complexity of the safety case for a high-level nuclear waste repository makes it imperative that deliberate and significant effort be made to incorporate in it a high level of transparency and traceability. Diverse audiences, from interested members of the public to highly trained subject matter experts, make this task difficult. A systematic study of the meaning of transparency and traceability and the implementation of the associated principles in preparing the safety case is, therefore, required. In this article, we review the existing knowledge and propose topics for further investigation. PMID:12017364

  19. Can Sisyphus succeed? Getting U.S. high-level nuclear waste into a geological repository.

    PubMed

    North, D Warner

    2013-01-01

    The U.S. government has the obligation of managing the high-level radioactive waste from its defense activities and also, under existing law, from civilian nuclear power generation. This obligation is not being met. The January 2012 Final Report from the Blue Ribbon Commission on America's Nuclear Future provides commendable guidance but little that is new. The author, who served on the federal Nuclear Waste Technical Review Board from 1989 to 1994 and subsequently on the Board on Radioactive Waste Management of the National Research Council from 1994 to 1999, provides a perspective both on the Commission's recommendations and a potential path toward progress in meeting the federal obligation. By analogy to Sisyphus of Greek mythology, our nation needs to find a way to roll the rock to the top of the hill and have it stay there, rather than continuing to roll back down again. PMID:23311528

  20. Perceived risk, stigma, and potential economic impacts of a high-level nuclear waste repository in Nevada

    SciTech Connect

    Slovic, P.; Layman, M.; Kraus, N.; Flynn, J.; Chalmers, J.; Gesell, G.

    1991-12-01

    This study investigates the potential impacts of the proposed nuclear waste repository at Yucca Mountain, Nevada, upon tourism, retirement and job-related migration, and business development in Las Vegas and the state. Adverse impacts may be expected to result from perceptions of risk, stigmatization, and socially amplified reactions to `unfortunate events` associated with the repository (major and minor accidents, discoveries of radiation releases, evidence of mismanagement, attempts to sabotage or disrupt the facility, etc.). The conceptual underpinnings of risk perception, stigmatization, and social amplification are discussed and empirical data are presented to demonstrate how nuclear images associated with Las Vegas and the State of Nevada might trigger adverse economic effects. The possibility that intense negative imagery associated with the repository may cause significant harm to Nevada`s economy can no longer be ignored by serious attempts to assess the risks and impacts of this unique facility. The behavioral processes described here appear relevant as well to the social impact assessment of any proposed facility that produces, uses, transports, or disposes of hazardous materials.

  1. Physico-chemical interactions at the concrete-bitumen interface of nuclear waste repositories

    NASA Astrophysics Data System (ADS)

    Bertron, A.; Ranaivomanana, H.; Jacquemet, N.; Erable, B.; Sablayrolles, C.; Escadeillas, G.; Albrecht, A.

    2013-07-01

    This study investigates the fate of nitrate and organic acids at the bitumenconcrete-steel interface within a repository storage cell for long-lived, intermediatelevel, radioactive wastes. The interface was simulated by a multiphase system in which cementitious matrices (CEM V-paste specimens) were exposed to bitumen model leachates consisting of nitrates and acetic acid with and without oxalic acid, chemical compounds likely to be released by bitumen. Leaching experiments were conducted with daily renewal of the solutions in order to accelerate reactions. C-steel chips, simulating the presence of steel in the repository, were added in the systems for some experiments. The concentrations of anions (acetate, oxalate, nitrate, and nitrite) and cations (calcium, potassium, ammonium) and the pH were monitored over time. Mineralogical changes of the cementitious matrices were analysed by XRD. The results confirmed the stability of nitrates in the absence of steel, whereas, reduction of nitrates was observed in the presence of steel (production of NH4+). The action of acetic acid on the cementitious matrix was similar to that of ordinary leaching; no specific interaction was detected between acetate and cementitious cations. The reaction of oxalic acid with the cementitious phases led to the precipitation of calcium oxalate salts in the outer layer of the matrix. The concentration of oxalate was reduced by 65% inside the leaching medium.

  2. Selection of candidate container materials for the conceptual waste package design for a potential high level nuclear waste repository at Yucca Mountain

    SciTech Connect

    Van Konynenburg, R.A.; Halsey, W.G.; McCright, R.D.; Clarke, W.L. Jr.; Gdowski, G.E.

    1993-02-01

    Preliminary selection criteria have been developed, peer-reviewed, and applied to a field of 41 candidate materials to choose three alloys for further consideration during the advanced conceptual design phase of waste package development for a potential high level nuclear waste repository at Yucca Mountain, Nevada. These three alloys are titanium grade 12, Alloy C-4, and Alloy 825. These selections are specific to the particular conceptual design outlined in the Site Characterization Plan. Other design concepts that may be considered in the advanced conceptual design phase may favor other materials choices.

  3. What comes to mind when you hear the words nuclear waste repository '': A study of 10,000 images

    SciTech Connect

    Slovic, P.; Layman, M.; Flynn, J.H. )

    1990-09-01

    Attempts by the federal government and the nuclear industry to develop sites for disposal of high-level and low-level radioactive wastes have been stymied by public and political opposition. The record of strenuous protest against nuclear waste repositories, as well as the findings of numerous public opinion surveys, make it clear that public opposition is widespread and deeply felt. It is also clear that there is an immense gap between the perceptions of the pubic and the views of technical experts and nuclear-industry officials. Given the seriousness of nuclear waste as a public issue, it is surprising that there have been only a few attempts to understand the deeper meaning of nuclear fears and opposition to nuclear waste disposal sites, and to provide some insight into the nature and pervasiveness of people's concerns. One step toward a deeper understanding would be to define the origins of these concerns, the emotions and images that underlie them, and their tractability or stability over time. In the present study, the authors recorded 10,000 word-association images from more than 3,300 respondents to four surveys during the period between April, 1988 and January 1, 1990. Each of the 10,000 images was assigned to one of thirteen general or superordinate categories, which expressed the dominant theme of the response. All but one superordinate categories contained subordinate categories. All in all there were 92 distinct categories. The two dominant superordinate categories, (1) negative consequences and (2) negative concepts accounted for more than 56% of the total number of images. Many of the smaller categories and subcategories were also quite negative in tone. The five leading subordinate categories, dangerous toxic, death sickness, environmental damage, bad, and scary, accounted for more than 42% of the total number of images. 27 refs., 6 tabs.

  4. Radiation effects on materials in the near-field of a nuclear waste repository. 1997 annual progress report

    SciTech Connect

    Wang, L.M.; Ewing, R.C.

    1997-11-25

    'Sheet silicates (e.g. micas and clays) are important constituents of a wide variety of geological formations such as granite, basalt, and sandstone. Sheet silicates, particularly clays such as bentonite are common materials in near-field engineered barriers in high-level nuclear waste (HLW) repositories. This is because migration of radionuclides from an underground HLW repository to the geosphere may be significantly reduced by sorption of radionuclides (e.g., Pu, U and Np) onto sheet silicates (e.g., clays and micas) that line the fractures and pores of the rocks along groundwater flowpaths. In addition to surface sorption, it has been suggested that some sheet silicates may also be able to incorporate many radionuclides, such as Cs and Sr, in the inter-layer sites of the sheet structure. However, theability of the sheet silicates to incorporate radionuclides and retard release and migration of radionuclides may be significantly affected by the near-field radiation due to the decay of fission products and actinides. for example, the unique properties of the sheet structures will be lost completely if the structure becomes amorphous due to irradiation effects. Thus, the study of irradiation effects on sheet-structures, such as structural damage and modification of chemical properties, are critical to the performance assessment of long-term repository behavior.'

  5. Nye County Nuclear Waste Repository Project Office independent scientific investigations program annual report, May 1997--April 1998

    SciTech Connect

    1998-07-01

    This annual summary report, prepared by the Nye County Nuclear Waste Repository Project Office (NWRPO), summarizes the activities that were performed during the period from May 1, 1997 to April 30, 1998. These activities were conducted in support of the Independent Scientific Investigation Program (ISIP) of Nye County at the Yucca Mountain Site (YMS). The Nye County NWRPO is responsible for protecting the health and safety of the Nye County residents. NWRPO`s on-site representative is responsible for designing and implementing the Independent Scientific Investigation Program (ISIP). Major objectives of the ISIP include: Investigating key issues related to conceptual design and performance of the repository that can have major impact on human health, safety, and the environment; identifying areas not being addressed adequately by the Department of Energy (DOE). Nye County has identified several key scientific issues of concern that may affect repository design and performance which were not being adequately addressed by DOE. Nye County has been conducting its own independent study to evaluate the significance of these issues. This report summarizes the results of monitoring from two boreholes and the Exploratory Studies Facility (ESF) tunnel that have been instrumented by Nye County since March and April of 1995. The preliminary data and interpretations presented in this report do not constitute and should not be considered as the official position of Nye County. The ISIP presently includes borehole and tunnel instrumentation, monitoring, data analysis, and numerical modeling activities to address the concerns of Nye County.

  6. Effect of transport-pathway simplifications on projected releases of radionuclides from a nuclear waste repository (Sweden)

    NASA Astrophysics Data System (ADS)

    Selroos, Jan-Olof; Painter, Scott L.

    2012-12-01

    The Swedish Nuclear Fuel and Waste Management Company has recently submitted an application for a license to construct a final repository for spent nuclear fuel, at approximately 500 m depth in crystalline bedrock. Migration pathways through the geosphere barrier are geometrically complex, with segments in fractured rock, deformation zones, backfilled tunnels, and near-surface soils. Several simplifications of these complex migration pathways were used in the assessments of repository performance that supported the license application. Specifically, in the geosphere transport calculations, radionuclide transport in soils and tunnels was neglected, and deformation zones were assumed to have transport characteristics of fractured rock. The effects of these simplifications on the projected performance of the geosphere barrier system are addressed. Geosphere performance is shown to be sensitive to how transport characteristics of deformation zones are conceptualized and incorporated into the model. Incorporation of advective groundwater travel time within backfilled tunnels reduces radiological dose from non-sorbing radionuclides such as I-129, while sorption in near-surface soils reduces radiological doses from sorbing radionuclides such as Ra-226. These results help quantify the degree to which geosphere performance was pessimistically assessed, and provide some guidance on how future studies to reduce uncertainty in geosphere performance may be focused.

  7. Current Status and Potential Impacts Regarding the Proposed Development of a Rail Line to the Yucca Mountain Nuclear Waste Repository

    SciTech Connect

    Lanthrum, G.; Gunnerson, J.

    2008-07-01

    This paper provides a description of the current status regarding the proposed development of a rail line to the Yucca Mountain Nuclear Waste Repository in Nye County, Southern Nevada, which includes potential impacts analyzed during the National Environmental Policy Act (NEPA) process, and the subsequent creation of an Environmental Impact Statement (EIS) for the rail line. Potential impacts are addressed within the context of impacts to natural and human environmental resources found within the geographic area of the proposed federal project. Potential impacts to these resources have been fully analyzed in the Rail Alignment Draft EIS (DEIS). This paper includes a summary of the potential impacts analyzed in the DEIS. Examples of potential impacts include land use conflicts, air quality, water use, and impacts to biological and cultural resources, among others. In conclusion: Based on its obligations under the NWPA and its decision to select the mostly rail scenario for the transportation of spent nuclear fuel and high-level radioactive waste, DOE needs to ship these materials by rail in Nevada to a repository at Yucca Mountain. DOE prepared the Rail Alignment EIS to provide the background, data, information, and analyses to help decision makers and the public understand the potential environmental impacts that could result from constructing and operating a railroad for shipment of spent nuclear fuel, high-level radioactive waste, and other materials from an existing rail line in Nevada to a repository at Yucca Mountain. This railroad would consist of a rail line, railroad operations support facilities, and other related infrastructure. DOE will use the Rail Alignment EIS to decide whether to construct and operate the proposed railroad, and if so, to: - Select a rail alignment (Caliente rail alignment or Mina rail alignment) in which to construct the railroad; - Select the common segments and alternative segments within either a Caliente rail alignment or a Mina

  8. Site characterization plan conceptual design report for a high-level nuclear waste repository in salt, vertical emplacement mode: Volume 1

    SciTech Connect

    Not Available

    1987-12-01

    This Conceptual Design Report describes the conceptual design of a high-level nuclear waste repository in salt at a proposed site in Deaf Smith County, Texas. Waste receipt, processing, packing, and other surface facility operations are described. Operations in the shafts underground are described, including waste hoisting, transfer, and vertical emplacement. This report specifically addresses the vertical emplacement mode, the reference design for the repository. Waste retrieval capability is described. The report includes a description of the layout of the surface, shafts, and underground. Major equipment items are identified. The report includes plans for decommissioning and sealing of the facility. The report discusses how the repository will satisfy performance objectives. Chapters are included on basis for design, design analyses, and data requirements for completion of future design efforts. 105 figs., 52 tabs.

  9. Recommended new criteria for the selection of nuclear waste repository sites in Columbia River basalt and US Gulf Coast domed salt

    SciTech Connect

    Steinborn, T.L.; Wagoner, J.L.; Qualheim, B.; Fitts, C.R.; Stetkar, R.E.; Turnbull, R.W.

    1980-06-16

    Screening criteria and specifications are recommended to aid in the evaluation of sites proposed for nuclear waste disposal in basalt and domed salt. The recommended new criteria proposed in this report are intended to supplement existing repository-related criteria for nuclear waste disposal. The existing criteria are contained in 10 CFR 60 sections which define siting criteria of the Nuclear Regulatory Commission (NRC), and ONWI 33(2) which defines siting criteria of the Office of Nuclear Waste Isolation (ONWI) for the Department of Energy. The specifications are conditions or parameter values that the authors recommend be applied in site acceptance evaluations. The siting concerns covered in this report include repository depth, host rock extent, seismic setting, structural and tectonic conditions, groundwater and rock geochemistry, volcanism, surface and subsurface hydrology, and socioeconomic issues, such as natural resources, land use, and population distribution.

  10. Effects of long-term exposure of tuffs to high-level nuclear waste-repository conditions. Preliminary report

    SciTech Connect

    Blacic, J.; Carter, J.; Halleck, P.; Johnson, P.; Shankland, T.; Andersen, R.; Spicochi, K.; Heller, A.

    1982-02-01

    Tests have been performed to explore the effects of extended exposure of tuffs from the southwestern portion of the Nevada Test Site to temperatures and pressures similar to those that will be encountered in a high-level nuclear waste repository. Tuff samples ranging from highly welded, nonzeolitized to unwelded, highly zeolitized varieties were subjected to temperatures of 80, 120, and 180{sup 0}C; confining pressures of 9.7 and 19.7 MPa; and water-pore pressures of 0.5 to 19.7 MPa for durations of 2 to 6 months. The following basic properties were measured before and after exposure and compared: tensile strength, uniaxial compressive strength, grain density, porosity, mineralogy, permeability, thermal expansion, and thermal conductivity. Depending on rock type and exposure conditions, significant changes in ambient tensile strength, compressive strength, grain density, and porosity were measured. Mineralogic examination, permeability, and thermal property measurements remain to be completed.

  11. Hydrothermal conditions and resaturation times in underground openings for a nuclear waste repository in the Umtanum flow at the Basalt Waste Isolation Project

    SciTech Connect

    Pruess, K.; Bodvarsson, G.

    1982-07-01

    Numerical simulation techniques have been used to study heat flow and pore fluid migration in the near field of storage tunnels and canister storage holes in a proposed high-level nuclear waste repository in the Umtanum Basalt at the Basalt Waste Isolation Project site at Hanford, Washington. Particular emphasis was placed on evaluating boiling conditions in the host rock. Sensitivity studies were performed to determine the influence of variations in critical site-specific parameters which are not presently accurately known. The results indicate that, even when rather extreme values are assumed for key hydrothermal parameters, the volume of rock dried by boiling of pore fluids is negligible compared to the volume of excavated openings. The time required for saturation of backfilling materials is thus controlled by the volume of the mined excavations. When realistic values for the parameters of the natural and man-made systems are used resaturation is predicted to occur within less than two years after backfilling is placed. The approximations used in the analyses, and their limitations, are discussed in the body of the report. Recommendations are made for additional studies of the thermohydrological behavior of a high-level nuclear waste repository. 31 references, 76 figures, 7 tables.

  12. Death Valley Lower Carbonate Aquifer Monitoring Program Wells Down gradient of the Proposed Yucca Mountain Nuclear Waste Repository

    SciTech Connect

    Inyo County

    2006-07-26

    Inyo County has participated in oversight activities associated with the Yucca Mountain Nuclear Waste Repository since 1987. The overall goal of these studies are the evaluation of far-field issues related to potential transport, by ground water, or radionuclides into Inyo County, including Death Valley, and the evaluation of a connection between the Lower Carbonate Aquifer (LCA) and the biosphere. Our oversight and completed Cooperative Agreement research, and a number of other investigators research indicate that there is groundwater flow between the alluvial and carbonate aquifers both at Yucca Mountain and in Inyo County. In addition to the potential of radionuclide transport through the LCA, Czarnecki (1997), with the US Geological Survey, research indicate potential radionuclide transport through the shallower Tertiary-age aquifer materials with ultimate discharge into the Franklin Lake Playa in Inyo County. The specific purpose of this Cooperative Agreement drilling program was to acquire geological, subsurface geology, and hydrologic data to: (1) establish the existence of inter-basin flow between the Amargosa Basin and Death Valley Basin; (2) characterize groundwater flow paths in the LCA through Southern Funeral Mountain Range, and (3) Evaluation the hydraulic connection between the Yucca Mountain repository and the major springs in Death Valley through the LCA.

  13. Closure development for high-level nuclear waste containers for the tuff repository; Phase 1, Final report

    SciTech Connect

    Robitz, E.S. Jr.; McAninch, M.D. Jr.; Edmonds, D.P. |

    1990-09-01

    This report summarizes Phase 1 activities for closure development of the high-level nuclear waste package task for the tuff repository. Work was conducted under U.S. Department of Energy (DOE) Contract 9172105, administered through the Lawrence Livermore National Laboratory (LLNL), as part of the Yucca Mountain Project (YMP), funded through the DOE Office of Civilian Radioactive Waste Management (OCRWM). The goal of this phase was to select five closure processes for further evaluation in later phases of the program. A decision tree methodology was utilized to perform an objective evaluation of 15 potential closure processes. Information was gathered via a literature survey, industrial contacts, and discussions with project team members, other experts in the field, and the LLNL waste package task staff. The five processes selected were friction welding, electron beam welding, laser beam welding, gas tungsten arc welding, and plasma arc welding. These are felt to represent the best combination of weldment material properties and process performance in a remote, radioactive environment. Conceptual designs have been generated for these processes to illustrate how they would be implemented in practice. Homopolar resistance welding was included in the Phase 1 analysis, and developments in this process will be monitored via literature in Phases 2 and 3. Work was conducted in accordance with the YMP Quality Assurance Program. 223 refs., 20 figs., 9 tabs.

  14. Thermal Analysis of Repository Codisposal Waste Packages Containing Aluminum Spent Nuclear Fuel

    SciTech Connect

    Lee, S.Y.

    1999-10-21

    The objective of this study is to develop a thermal analysis methodology and to perform analyses of codisposal storage configurations to estimate the SNF, HWGL, and WP temperatures in a geological repository for various boundary conditions.

  15. AEGIS technology demonstration for a nuclear waste repository in basalt. Assessment of effectiveness of geologic isolation systems

    SciTech Connect

    Dove, F.H.; Cole, C.R.; Foley, M.G.

    1982-09-01

    A technology demonstration of current performance assessment techniques as applied to a nuclear waste repository in the Columbia Plateau Basalts was conducted. Hypothetical repository coordinates were selected for an actual geographical setting on the Hanford Reservation in the state of Washington. Published hydrologic and geologic data used in the analyses were gathered in 1979 or earlier. The following report documents the technology demonstration in basalt. Available information has been used to establish the data base and initial hydrologic and geologic interpretations for this site-specific application. A simplified diagram of the AEGIS analyses is shown. Because an understanding of the dynamics of ground-water flow is essential to the development of release scenarios and consequence analyses, a key step in the demonstration is the systems characterization contained in the conceptual model. Regional and local ground-water movement patterns have been defined with the aid of hydrologic computer models. Hypothetical release scenarios have been developed and evaluated by a process involving expert opinion and a Geologic Simulation Model for basalt. (The Geologic Simulation Model can also be used to forecast future boundary conditions for the hydrologic simulation.) Chemical reactivity of the basalt with ground water will influence the leaching and transport of radionuclides; solubility equilibria based on available data are estimated with geochemical models. After the radionuclide concentrations are mathematically introduced into the ground-water movement patterns, waste movement patterns are outlined over elapsed time. Contaminant transport results are summarized for significant radionuclides that are hypothetically released to the accessible environment and to the biosphere.

  16. Study of thermo-hydro-mechanical processes at a potential site of an Indian nuclear waste repository

    NASA Astrophysics Data System (ADS)

    Maheshwar, Sachin; Verma, A. K.; Singh, T. N.; Bajpai, R. K.

    2015-12-01

    A detailed scientific study is required for the disposal of high-level radioactive wastes because they generate extremely high heat during their half-life period. Although, several methods have been proposed for the disposal of nuclear wastes, deep underground repository is considered to be a suitable option. In this paper, field investigation has been done near to Bhima basin of peninsular India. Detailed fracture analysis near the borehole shows very prominent maxima of fractures striking N55∘E coinciding with the trace of master basement cover metasediment fault. Physico-mechanical properties of rocks have been determined in the laboratory. The host rock chosen is granite and engineered barrier near the canister is proposed to be clay. A thermo-hydro-mechanical (THM) analysis has been done to study the effect of heat on deformations, stresses and pore-pressure variation in granite and clay barriers. For this purpose, finite difference method has been used. Suitable rheological models have been used to model elastic canister and elasto-plastic engineered barrier and host rock. It has been found that both temperature and stresses at any point in the rockmass is below the design criteria which are 100∘C for temperature and 0.2 for damage number.

  17. INDIVIDUAL DOSIMETRY IN DISPOSAL REPOSITORY OF HEAT-GENERATING NUCLEAR WASTE.

    PubMed

    Pang, Bo; Saurí Suárez, Héctor; Becker, Frank

    2016-09-01

    Certain working scenarios in a disposal facility of heat-generating nuclear waste might lead to an enhanced level of radiation exposure for workers in such facilities. Hence, a realistic estimation of the personal dose during individual working scenarios is desired. In this study, the general-purpose Monte Carlo N-Particle code MCNP6 (Pelowitz, D. B. (ed). MCNP6 user manual LA-CP-13-00634, Rev. 0 (2013)) was applied to simulate a representative radiation field in a disposal facility. A tool to estimate the personal dose was then proposed by taking into account the influence of individual motion sequences during working scenarios. As basis for this approach, a movable whole-body phantom was developed to describe individual body gestures of the workers during motion sequences. In this study, the proposed method was applied to the German concept of geological disposal in rock salt. The feasibility of the proposed approach was demonstrated with an example of working scenario in an emplacement drift of a rock salt mine. PMID:27150513

  18. SYNTHESIS AND PERFORMANCE OF FE-BASED AMORPHOUS ALLOYS FOR NUCLEAR WASTE REPOSITORY APPLICATIONS

    SciTech Connect

    Kaufman, L; Perepezko, J; Hildal, K

    2007-02-08

    In several Fe-based alloy systems it is possible to produce glasses with cooling rates as low as 100 K/s that exhibit outstanding corrosion resistance compared to typical crystalline alloys such as high-performance stainless steels and Ni-based C-22 alloy. Moreover, novel alloy compositions can be synthesized to maximize corrosion resistance (i.e. adding Cr and Mo) and to improve radiation compatibility (adding B) and still maintain glass forming ability. The applicability of Fe-based amorphous coatings in typical environments where corrosion resistance and thermal stability are critical issues has been examined in terms of amorphous phase stability and glass-forming ability through a coordinated computational analysis and experimental validation. Similarly, a novel computational thermodynamics approach has been developed to explore the compositional sensitivity of glass-forming ability and thermal stability. Also, the synthesis and characterization of alloys with increased cross-section for thermal neutron capture will be outlined to demonstrate that through careful design of alloy composition it is possible to tailor the material properties of the thermally spray-formed amorphous coating to accommodate the challenges anticipated in typical nuclear waste storage applications over tens of thousands of years in a variety of corrosive environments.

  19. A compound power-law model for volcanic eruptions: Implications for risk assessment of volcanism at the proposed nuclear waste repository at Yucca Mountain, Nevada

    SciTech Connect

    Ho, Chih-Hsiang

    1994-10-17

    Much of the ongoing debate on the use of nuclear power plants in U.S.A. centers on the safe disposal of the radioactive waste. Congress, aware of the importance of the waste issue, passed the Nuclear Waste Policy Act of 1982, requiring the federal government to develop a geologic repository for the permanent disposal of high level radioactive wastes from civilian nuclear power plants. The Department of Energy (DOE) established the Office of Civilian Radioactive Waste Management (OCRWM) in 1983 to identify potential sites. When OCRWM had selected three potential sites to study, Congress enacted the Nuclear Waste Policy Amendments Act of 1987, which directed the DOE to characterize only one of those sites, Yucca Mountain, in southern Nevada. For a site to be acceptable, theses studies must demonstrate that the site could comply with regulations and guidelines established by the federal agencies that will be responsible for licensing, regulating, and managing the waste facility. Advocates and critics disagree on the significance and interpretation of critical geological features which bear on the safety and suitability of Yucca Mountain as a site for the construction of a high-level radioactive waste repository. Recent volcanism in the vicinity of Yucca Mountain is readily recognized as an important factor in determining future public and environmental safety because of the possibility of direct disruption of a repository site by volcanism. In particular, basaltic volcanism is regarded as direct and unequivocal evidence of deep-seated geologic instability. In this paper, statistical analysis of volcanic hazard assessment at the Yucca Mountain site is discussed, taking into account some significant geological factors raised by experts. Three types of models are considered in the data analysis. The first model assumes that both past and future volcanic activities follow a homogeneous Poisson process (HPP).

  20. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    SciTech Connect

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  1. Environmental and health impacts of February 14, 2014 radiation release from the nation's only deep geologic nuclear waste repository.

    PubMed

    Thakur, P; Lemons, B G; Ballard, S; Hardy, R

    2015-08-01

    The environmental impact of the February 14, 2014 radiation release from the nation's only deep geologic nuclear waste repository, the Waste Isolation Pilot Plant (WIPP) was assessed using monitoring data from an independent monitoring program conducted by the Carlsbad Environmental Monitoring & Research Center (CEMRC). After almost 15 years of safe and efficient operations, the WIPP had one of its waste drums rupture underground resulting in the release of moderate levels of radioactivity into the underground air. A small amount of radioactivity also escaped to the surface through the ventilation system and was detected above ground. It was the first unambiguous release from the WIPP repository. The dominant radionuclides released were americium and plutonium, in a ratio that matches the content of the breached drum. The accelerated air monitoring campaign, which began following the accident, indicates that releases were low and localized, and no radiation-related health effects among local workers or the public would be expected. The highest activity detected was 115.2 μBq/m(3) for (241)Am and 10.2 μBq/m(3) for (239+240)Pu at a sampling station located 91 m away from the underground air exhaust point and 81.4 μBq/m(3) of (241)Am and 5.8 μBq/m(3) of (239+240)Pu at a monitoring station located approximately one kilometer northwest of the WIPP facility. CEMRC's recent monitoring data show that the concentration levels of these radionuclides have returned to normal background levels and in many instances, are not even detectable, demonstrating no long-term environmental impacts of the recent radiation release event at the WIPP. This article presents an evaluation of almost one year of environmental monitoring data that informed the public that the levels of radiation that got out to the environment were very low and did not, and will not harm anyone or have any long-term environmental consequence. In terms of radiological risk at or in the vicinity of the

  2. Final Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada

    SciTech Connect

    N /A

    2002-10-25

    The purpose of this environmental impact statement (EIS) is to provide information on potential environmental impacts that could result from a Proposed Action to construct, operate and monitor, and eventually close a geologic repository for the disposal of spent nuclear fuel and high-level radioactive waste at the Yucca Mountain site in Nye County, Nevada. The EIS also provides information on potential environmental impacts from an alternative referred to as the No-Action Alternative, under which there would be no development of a geologic repository at Yucca Mountain.

  3. Clinoptilolite compositions in diagenetically-altered tuffs at a potential nuclear waste repository, Yucca Mountain, Nevada

    SciTech Connect

    Broxton, D.E.

    1987-12-31

    The compositions of Yucca Mountain clinoptilolites and their host tuffs are highly variable. Clinoptilolites and heulandites in fractures near the repository and in a thin, altered zone at the top of the Topopah Spring basal vitrophyre have consistent calcium-rich compositions. Below this level, clinoptilolites in thick zones of diagenetic alteration on the east side of Yucca Mountain have calcic-potassic compositions and become more calcium rich with depth. Clinoptilolites in stratigraphically equivalent tuffs to the west have sodic-potassic compositions and become more sodic with depth. Clinoptilolite properties important for repository performance assessment include thermal expansion/contraction behavior, hydration/dehydration behavior, and ion-exchange properties. These properties can be significantly affected by clinoptilolite compositions. The compositional variations for clinoptilolites found by this study suggest that the properties will vary vertically and laterally at Yucca Mountain. Used in conjunction with experimental data, the clinoptilolite compositions presented here can be used to model the behavior of clinoptilolites in the repository environment and along transport pathways.

  4. Importance of thermo-osmosis for fluid flow and transport in clay formations hosting a nuclear waste repository

    NASA Astrophysics Data System (ADS)

    Gonçalvès, Julio; de Marsily, Ghislain; Tremosa, Joachim

    2012-07-01

    Three osmotic processes have been identified in clay-rich media. Electro- and chemo-osmosis - flows of water caused by salinity and electrical potential gradients - have so far attracted almost exclusive attention. But, despite the recurring concern about the importance of thermo-osmosis - a flow of water driven by a temperature gradient - in argillaceous media, it remains largely neglected. Here we propose a new formalism for estimating the thermo-osmotic permeability based on a theoretical analysis at the molecular and pore scale, then upscaled. We show that the thermo-osmotic permeability can be estimated only from surface-charge density, temperature, pore size and salinity. The possible prominent role of thermo-osmosis in compacted shale layers with a temperature gradient is then exemplified. This first general estimate of the thermo-osmotic permeability can be used to improve our understanding of the influence on fluid flow and pressure fields of the natural geothermal gradient in sedimentary basins, which is required, e.g., for safety assessments of nuclear-waste repositories in shale layers.

  5. Images of a place and vacation preferences: Implications of the 1989 surveys for assessing the economic impacts of a nuclear waste repository in Nevada

    SciTech Connect

    Slovic, P.; Layman, M.; Flynn, J.H.

    1990-11-01

    In July, 1989 the authors produced a report titled Perceived Risk, Stigma, and Potential Economic Impacts of a High-Level Nuclear-Waste Repository in Nevada (Slovic et al., 1989). That report described a program of research designed to assess the potential impacts of a high-level nuclear waste repository at Yucca Mountain, Nevada upon tourism, retirement and job-related migration, and business development in Las Vegas and the state. It was concluded that adverse economic impacts potentially may result from two related social processes. Specifically, the study by Slovic et al. employed analyses of imagery in order to overcome concerns about the validity of direct questions regarding the influence of a nuclear-waste repository at Yucca Mountain upon a person`s future behaviors. During the latter months of 1989, data were collected in three major telephone surveys, designed to achieve the following objectives: (1) to replicate the results from the Phoenix, Arizona, surveys using samples from other populations that contribute to tourism, migration, and development in Nevada; (2) to retest the original Phoenix respondents to determine the stability of their images across an 18-month time period and to determine whether their vacation choices subsequent to the first survey were predictable from the images they produced in that original survey; (3) to elicit additional word-association images for the stimulus underground nuclear waste repository in order to determine whether the extreme negative images generated by the Phoenix respondents would occur with other samples of respondents; and (4) to develop and test a new method for imagery elicitation, based upon a rating technique rather than on word associations. 2 refs., 8 figs., 13 tabs.

  6. Projected costs for mined geologic repositories for dispoal of commercial nuclear wastes

    SciTech Connect

    Waddell, J.D.; Dippold, D.G.; McSweeney, T.I.

    1982-12-01

    This documen reports cost estimates for: (1) the exploration and development activities preceding the final design of terminal isolation facilities for disposal of commercial high-level waste; and (2) the design, construction, operation, and decommissioning of such facilities. Exploration and evelopment costs also include a separate cost category for related programs such as subseabed research, activities of the Transportation Technology Center, and waste disposal impact mitigation activities.

  7. Application of Non-Human Biota Assessment Methodologies to the Assessment of Potential Impacts from a Nuclear Waste Repository

    SciTech Connect

    Smith, K.L.; Robinson, C.A.; Ikonen, A.T.K.

    2007-07-01

    The protection of the environment from the effects of ionising radiation has become increasingly more topical over the last few years as the intentions enshrined in international principles and agreements have become more binding through national and international law. For example, the Directive on impact of certain projects on the environment (EIA Directive 85/337/EEC) [CEC, 1985], amended in 1997 [CEC, 1997], places a mandatory requirement on all EU Member States to conduct environmental impact assessments for a range of project having potential impact on the environment, including radioactive waste disposal. Such assessments must consider humans, fauna and flora, the abiotic environment (soil, water, air), material assets and cultural heritage as well as the interactions between these factors. In Finland, Posiva Oy are responsible for the overall repository programme for spent nuclear fuel and, as such, are conducting the Safety Case Assessment for a proposed geological repository for nuclear waste. Within the European legislation framework, the Finnish regulatory body requires that the repository safety case assessment should include not only human radiological safety, but also an assessment of the potential impact upon populations of non-human biota. Specifically, the Safety Case should demonstrate that there will be: - no decline in the biodiversity of currently living populations; - no significant detriment to populations of fauna and flora; and, - no detrimental effects on individuals of domestic animals and rare plants and animals. At present, there are no internationally agreed criteria that explicitly address protection of the environment from ionising radiation. However, over recent years a number of assessment methodologies have been developed including, at a European level, the Framework for the Assessment of Environmental impact (FASSET) and Environmental Risks from Ionising Contaminants (ERICA). The International Committee on Radiation Protection

  8. Results from an International Simulation Study on Coupled Thermal,Hydrological, and Mechanical (THM) Processes near Geological NuclearWaste Repositories

    SciTech Connect

    Rutqvist, Jonny; Rutqvist, J.; Barr, D.; Birkholzer, J.T.; Chijimatsu, M.; Kolditz, O.; Liu, Q.-S; Oda, Y.; Wang, W.; Zhang, C.-Y.

    2007-10-23

    As part of the ongoing international DECOVALEX project, four research teams used five different models to simulate coupled thermal, hydrological, and mechanical (THM) processes near waste emplacement drifts of geological nuclear waste repositories. The simulations were conducted for two generic repository types, one with open and the other with back-filled repository drifts, under higher and lower postclosure temperatures, respectively. In the completed first model inception phase of the project, a good agreement was achieved between the research teams in calculating THM responses for both repository types, although some disagreement in hydrological responses is currently being resolved. In particular, good agreement in the basic thermal-mechanical responses was achieved for both repository types, even though some teams used relatively simplified thermal-elastic heat-conduction models that neglected complex near-field thermal-hydrological processes. The good agreement between the complex and simplified process models indicates that the basic thermal-mechanical responses can be predicted with a relatively high confidence level.

  9. Mineralogical characterization of selected shales in support of nuclear waste repository studies: Progress report

    SciTech Connect

    Lee, S.Y.; Hyder, L.K.; Alley, P.D.

    1987-12-01

    Because baseline characterization of shale mineralogy is critical to the interpretation of results from experiments on radionuclide retardation, groundwater-shale interactions, and physicochemical characteristics, a protocol for quantitative mineralogical analyses has been developed by integrating geochemical and instrumental techniques for the investigation of properties related to repository performance. Thermal analyses were used to estimate total organic matter and carbonate mineral contents. Scanning electron microscope backscattering and elemental mapping of polished sectors and particle-size distribution data were used to estimate the amounts of quartz plus feldspar and pyrite in the shales. X-ray diffraction, neutron activation, and size-distribution data were utilized to estimate phyllosilicate mineral contents. High-resolution transmission electron microscopy was used to identify clay mineral components.

  10. A probabilistic approach to rock mechanical property characterization for nuclear waste repository design

    SciTech Connect

    Kim, Kunsoo; Gao, Hang

    1996-04-01

    A probabilistic approach is proposed for the characterization of host rock mechanical properties at the Yucca Mountain site. This approach helps define the probability distribution of rock properties by utilizing extreme value statistics and Monte Carlo simulation. We analyze mechanical property data of tuff obtained by the NNWSI Project to assess the utility of the methodology. The analysis indicates that laboratory measured strength and deformation data of Calico Hills and Bullfrog tuffs follow an extremal. probability distribution (the third type asymptotic distribution of the smallest values). Monte Carlo simulation is carried out to estimate rock mass deformation moduli using a one-dimensional tuff model proposed by Zimmermann and Finley. We suggest that the results of these analyses be incorporated into the repository design.

  11. Reliability of instrumentation in a simulated nuclear-waste repository environment

    SciTech Connect

    Patrick, W.C.; Rector, N.L.

    1983-06-01

    In light of the observed performance of the geotechnical instrumentation deployed on the Spent Fuel Test-Climax (SFT-C), the following conclusions and recommendations are offered. Further research is required to fully understand the observed failures of linear potentiometers utilized in sealed or partially ventilated extensometer head assemblies. Based on our field observations, we recommend deploying Schaevitz LVDTs or proximeters as extensometer transducers where a sealed head assembly is required. The user must be cognizant of the potential drift and thermal instabilities of these units, however. The first-generation wire extensometers and fracture monitors developed for this test are an accurate, reliable means for measuring convergence and discrete joint motion, respectively. The improved hermetically sealed vibrating-wire stressmeters function reliably. Calibration of the gauge remains difficult and further work is warranted in this area. Utilization of a single lot of sheathed thermocouples in a zone box configuration is a cost-effective, accurate, and reliable means of measuring temperatures in the repository environment. Care must be taken to tailor the sheath composition to the test thermal and chemical environment. Monitoring and post-test studies will continue at the SFT-C through 1984. Included in these studies will be post-test calibrations of all accessible instrumentation. A final report on the performance of the field instrumentation will be prepared at that time.

  12. Assessment of the potential for tectonic fault rupture for high-level nuclear waste repositories

    SciTech Connect

    Swan, F.H.; Stepp, J.C.; McGuire, R.K.

    1993-09-01

    Active faults that extend to or near the Earth`s surface may threaten the safety of engineered structures. The threat can be mitigated by appropriate siting and design, which requires understanding of the characteristics and magnitude of the faulting hazard based on detailed site investigations and assessment of the characteristics of faulting that has occurred under the present tectonic regime in the site area. Both deterministic and probabilistic approaches are used to assess hazards due to fault rupture for engineering design. A combined probabilistic-deterministic approach provides the broadest perspective both for evaluating the potential fault rupture hazard and for selecting design criteria, which may differ among the various components of the repository depending on their function and importance to safety. Probabilistic analyses that explicitly incorporates uncertainties in parameters that characterize fault activity, the nature and amount of deformation, and the likelihood of occurrence, as well as uncertainties in the analytical methods, enables reasonable design parameters to be selected and the identification of the input parameters and analytical methods that dominate the hazard. Deterministic analyses can then be made to examine in detail those factors that dominate the fault rupture hazard.

  13. Preliminary total-system analysis of a potential high-level nuclear waste repository at Yucca Mountain

    SciTech Connect

    Eslinger, P.W.; Doremus, L.A.; Engel, D.W.; Miley, T.B.; Murphy, M.T.; Nichols, W.E.; White, M.D.; Langford, D.W.; Ouderkirk, S.J.

    1993-01-01

    The placement of high-level radioactive wastes in mined repositories deep underground is considered a disposal method that would effectively isolate these wastes from the environment for long periods of time. This report describes modeling performed at PNL for Yucca Mountain between May and November 1991 addressing the performance of the entire repository system related to regulatory criteria established by the EPA in 40 CFR Part 191. The geologic stratigraphy and material properties used in this study were chosen in cooperation with performance assessment modelers at Sandia National Laboratories (SNL). Sandia modeled a similar problem using different computer codes and a different modeling philosophy. Pacific Northwest Laboratory performed a few model runs with very complex models, and SNL performed many runs with much simpler (abstracted) models.

  14. Characteristics of potential repository wastes

    SciTech Connect

    Cowart, C.G.; Notz, K.J.

    1992-10-01

    This report presents the results of a fully documented peer review of DOE/RW-0184, Rev. 1, Characteristics of Potential Repository Wastes''. The peer review was chaired and administered by oak Ridge National Laboratory (ORNL) for the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM) and was conducted in accordance with OCRWM QA procedure QAAP 3.3 Peer Review'' for the purpose of quailing the document for use in OCRWM quality-affecting work. The peer reviewers selected represent a wide range of experience and knowledge particularly suitable for evaluating the subject matter. A total of 596 formal comments were documented by the seven peer review panels, and all were successfully resolved. The peers reached the conclusion that DOE/RW-0184, Rev. 1, is quality determined and suitable for use in quality-affecting work.

  15. Measurements of electrical conductivity for characterizing and monitoring nuclear waste repositories

    SciTech Connect

    Morrison, H.F.; Becker, A.; Lee, K.H.

    1986-11-01

    The detection of major fractures is one topic of this study but another equally important problem is to develop quantitative relationships between large scale resistivity and fracture systems in rock. There has been very little work done on this central issue. Empirical relations between resistivity and porosity have been derived on the basis of laboratory samples or from well logging, but there are no comparable 'laws' for rock masses with major fracture or joint patterns. Hydrologic models for such rocks have been recently been derived but the corresponding resistivity models have not been attempted. Resistivity due to fracture distributions with preferred orientation could be determined with such models, as could quantitative interpretation of changes as fracture aperature varies with load. This study is not only important for the assessment of a repository site, but has far ranging implications in reservoir studies for oil, gas, and geothermal resources. The electrical conductivity can be measured in two ways. Current can be injected into the ground through pairs of electrodes and corresponding voltage drops can be measured in the vicinity with other pairs of electrodes. The electrical conductivity can also be measured inductively. Instead of injecting current into the ground as described in the dc resistivity method, currents can be induced to flow by a changing magnetic field. In these inductive or electromagnetic (em) methods the interpretation depends both on transmitter-receiver geometry and frequency of operation. In principle the interpretation should be more definitive than with the dc resistivity methods. Rigorous confirmation of this statement in inhomogeneous media awaits the development of generalized inversion techniques for em methods.

  16. Factors influencing the performance of carbon steel overpacks in the proposed high-level nuclear waste repository

    SciTech Connect

    Cragnolino, G.A.; Dunn, D.S.; Angell, P.; Pan, Y.M.; Sridhar, N.

    1998-12-31

    A C-Mn steel, ASTM A516 Grade 55, is the primary candidate material for the outer metallic barrier in the current advanced conceptual design for the waste package in the proposed high-level radioactive waste repository at Yucca Mountain. The expected performance of this steel and that of the alternate material, A387 Grade 22 (2 1/4Cr-1Mo) steel, as affected by thermal embrittlement, dry or humid air oxidation, uniform and localized aqueous corrosion, microbially influenced corrosion, and stress corrosion cracking, is discussed on the basis of experimental studies and a review of information and data available in the literature.

  17. Supplemental Performance Analyses for Igneous Activity and Human Intrusion at the Potential High-Level Nuclear Waste Repository at Yucca Mountain

    SciTech Connect

    Swift, P.; Gaither, K.; Freeze, G.; McCord, J.; Kalinich, D.; Saulnier, G.; Statham, W.

    2002-02-26

    The U.S. Department of Energy (DOE) is considering the possible recommendation of a site at Yucca Mountain, Nevada, for the potential development of a geologic repository for the disposal of high-level radioactive waste and spent nuclear fuel. Consequences of hypothetical disruption of the Yucca Mountain site by igneous activity or human intrusion have been evaluated in the Yucca Mountain Science and Engineering Report (S&ER) (1), which presents technical information supporting the consideration of the possible site recommendation. Since completion of the S&ER, supplemental analyses have examined possible impacts of new information and alternative assumptions on the estimates of the consequences of these events. Specifically, analyses of the consequences of igneous disruption address uncertainty regarding: (1) the impacts of changes in the repository footprint and waste package spacing on the probability of disruption; (2) impacts of alternative assumptions about the appropriat e distribution of future wind speeds to use in the analysis; (3) effects of alternative assumptions about waste particle sizes; and (4) alternative assumptions about the number of waste packages damaged by igneous intrusion; and (5) alternative assumptions about the exposure pathways and the biosphere dose conversion factors used in the analysis. Additional supplemental analyses, supporting the Final Environmental Impact Statement (FEIS), have examined the results for both igneous disruption and human intrusion, recalculated for a receptor group located 18 kilometers (km) from the repository (the location specified in 40 CFR 197), rather than at the 20 km distance used in the S&ER analyses.

  18. A literature review of coupled thermal-hydrologic-mechanical-chemical processes pertinent to the proposed high-level nuclear waste repository at Yucca Mountain

    SciTech Connect

    Manteufel, R.D.; Ahola, M.P.; Turner, D.R.; Chowdhury, A.H.

    1993-07-01

    A literature review has been conducted to determine the state of knowledge available in the modeling of coupled thermal (T), hydrologic (H), mechanical (M), and chemical (C) processes relevant to the design and/or performance of the proposed high-level waste (HLW) repository at Yucca Mountain, Nevada. The review focuses on identifying coupling mechanisms between individual processes and assessing their importance (i.e., if the coupling is either important, potentially important, or negligible). The significance of considering THMC-coupled processes lies in whether or not the processes impact the design and/or performance objectives of the repository. A review, such as reported here, is useful in identifying which coupled effects will be important, hence which coupled effects will need to be investigated by the US Nuclear Regulatory Commission in order to assess the assumptions, data, analyses, and conclusions in the design and performance assessment of a geologic reposit``. Although this work stems from regulatory interest in the design of the geologic repository, it should be emphasized that the repository design implicitly considers all of the repository performance objectives, including those associated with the time after permanent closure. The scope of this review is considered beyond previous assessments in that it attempts with the current state-of-knowledge) to determine which couplings are important, and identify which computer codes are currently available to model coupled processes.

  19. Materials in Nuclear Waste Disposition

    NASA Astrophysics Data System (ADS)

    Rebak, Raul B.

    2014-03-01

    Commercial nuclear energy has been used for over 6 decades; however, to date, none of the 30+ countries with nuclear power has opened a repository for high-level waste (HLW). All countries with nuclear waste plan to dispose of it in metallic containers located in underground geologically stable repositories. Some countries also have liquid nuclear waste that needs to be reduced and vitrified before disposition. The five articles included in this topic offer a cross section of the importance of alloy selection to handle nuclear waste at the different stages of waste processing and disposal.

  20. Assessing materials (''Getters'') to immobilize or retard the transport of technetium through the engineered barrier system at the potential Yucca Mountain nuclear waste repository

    SciTech Connect

    Viani, B E

    1999-03-15

    Current performance assessment calculations show that technetium (Tc) and neptunium (Np) will deliver the major fraction of the radiation dose to the accessible environment from the potential Yucca Mountain nuclear waste repository. Therefore, materials that can immobilize or delay the transport of Tc or Np (getters) are being considered for addition to either the waste-package or the backfill adjacent to the waste-package. Of the two radionuclides, Tc presents the greater challenge in identifying a suitable getter material. This report identifies several materials that warrant further consideration for immobilizing and/or sorbing Tc as additives to the backfill, and recommends active carbon and an inorganic oxide for initial testing. Other materials, such as zero valent iron, might be useful as getters if they were placed in the waste package itself, a subject that merits further investigation.

  1. Identification and characterization of potential discharge areas for radionuclide transport by groundwater from a nuclear waste repository in Sweden.

    PubMed

    Berglund, Sten; Bosson, Emma; Selroos, Jan-Olof; Sassner, Mona

    2013-05-01

    This paper describes solute transport modeling carried out as a part of an assessment of the long-term radiological safety of a planned deep rock repository for spent nuclear fuel in Forsmark, Sweden. Specifically, it presents transport modeling performed to locate and describe discharge areas for groundwater potentially carrying radionuclides from the repository to the surface where man and the environment could be affected by the contamination. The modeling results show that topography to large extent determines the discharge locations. Present and future lake and wetland objects are central for the radionuclide transport and dose calculations in the safety assessment. Results of detailed transport modeling focusing on the regolith and the upper part of the rock indicate that the identification of discharge areas and objects considered in the safety assessment is robust in the sense that it does not change when a more detailed model representation is used. PMID:23619801

  2. Perceived risk, stigma, and potential economic impacts of a high-level nuclear waste repository in Nevada

    SciTech Connect

    Slovic, P.

    1989-12-31

    This paper addresses the potential for the proposed Yucca Mountain repository to have serious adverse economic impacts on the city of Las Vegas and the State of Nevada. Adverse economic impacts may be expected to result from two related social processes. One has to do with perceptions of risk and socially amplified reactions to unfortunate events associated with the repository (major and minor accidents, discoveries of radiation releases, evidence of mismanagement, attempts to sabotage or disrupt the facility, etc.). The second process that may trigger significant adverse impacts is that of stigmatization. The conceptual underpinnings of risk perception, social amplification, and stigma are discussed in this paper and empirical data are presented to demonstrate how nuclear images associated with Las Vegas and the State of Nevada might trigger adverse effects on tourism, migration, and business development.

  3. Bridging the Gap in the Chemical Thermodynamic Database for Nuclear Waste Repository: Studies of the Effect of Temperature on Actinide Complexation

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin; Xia, Yuanxian; Friese, Judah I.; Zanonato, PierLuigi; Di Bernardo, Plinio

    2009-12-21

    Recent results of thermodynamic studies on the complexation of actinides (UO{sub 2}{sup 2+}, NpO{sub 2}{sup +} and Pu{sup 4+}) with F{sup -}, SO{sub 4}{sup 2-} and H{sub 2}PO{sub 4}{sup -}/HPO{sub 4}{sup 2-} at elevated temperatures are reviewed. The data indicate that, for all systems except the 1:1 complexation of Np(V) with HPO{sub 4}{sup 2-}, the complexation of actinides is enhanced by the increase in temperature. The enhancement is primarily due to the increase in the entropy term (T{Delta}S) that exceeds the increase in the enthalpy ({Delta}H) as the temperature is increased. These data bridge the gaps in the chemical thermodynamic database for nuclear waste repository where the temperature could remain significantly higher than 25 C for a long time after the closure of the repository.

  4. Progress in evaluation of radionuclide geochemical information developed by DOE high-level nuclear waste repository site projects. Annual report, October 1984-September 1985. Volume 4

    SciTech Connect

    Meyer, R.E.; Arnold, W.D.; Blencoe, J.G.; Jacobs, G.K.; Kelmers, A.D.; Seeley, F.G.; Whatley, S.K.

    1986-05-01

    Information pertaining to the potential geochemical behavior of radionuclides at candidate sites for a high-level radioactive waste repository, which is being developed by projects within the Department of Energy (DOE), is being evaluated by Oak Ridge National Laboratory for the Nuclear Regulatory Commission (NRC). During this report period, emphasis was placed on the evaluation of information pertinent to the Hanford site in southeastern Washington. Results on the sorption/solubility behavior of technetium, neptunium, and uranium in the basalt/water geochemical system are summarized and compared to the results of DOE. Also, summaries of results are reported from two geochemical modeling studies: (1) an evaluation of the information developed by DOE on the native copper deposits of Michigan as a natural analog for the emplacement of copper canisters in a repository in basalt, and (2) calculation of the solubility and speciation of radionuclides for representative groundwaters from the Yucca Mountain site in Nevada.

  5. Investigation of environmentally assisted fracture of metallic nuclear waste package barrier materials in simulated basalt repository environments

    SciTech Connect

    Pitman, S.G.

    1982-11-01

    Statically loaded corrosion tests, slow strain rate (SSR) tests, and fatigue crack growth rate (FCGR) tests were conducted to evaluate the relative susceptibility of two titanium-base nuclear waste package candidate structural barrier materials Ti-grade 2 and Ti-grade 12-to environmentally enhanced cracking in a simulated repository environment. Statically loaded corrosion tests were done in oxic basalt ground water at 250/sup 0/C; SSR tests were done in oxic basalt ground water at 150, 250, and 300/sup 0/C and in air at 20 and 250/sup 0/C; and FCGR tests were done in basalt ground water, fluoride-ion-enhanced basalt ground water, high-purity water, and air at 90/sup 0/C. The following conclusions can be drawn: the general corrosion rate of statically loaded corrosion coupons was very low in a 3-mo test, and no pitting or cracking of the specimens was observed. Ti-grade 2 and Ti-grade 12 exhibited strain rate dependent ductility diminution in SSR tests. The ductility diminution was most severe in Ti-grade 2 at 300/sup 0/C and in Ti-grade 12 at 250/sup 0/C. For of Ti-grade 12 it was found to be highly orientation dependent. The ductility diminution was also found in tests conducted in air as well as in those conducted in the basalt ground water environment; however, the extent of the degradation was less in air. The ductility diminution cannot be attributed to stress corrosion cracking because the fracture mode was microvoid coalescence in all tests. Evidence obtained in the current study and correlation of the present results with results obtained by other researchers indicate that dynamic strain aging is responsible for the loss of ductility. The FCGR of Ti-grade 2 and Ti-grade 12 was not affected by any of the environmental conditions used in this study, which indicates that no environmental cracking mechanism is operative under the conditions tested (90/sup 0/C, oxic ground water, and frequencies from 0.01 to 5 Hz).

  6. Long-Term Modeling of Coupled Processes in a Generic Salt Repository for Heat-Generating Nuclear Waste: Analysis of the Impacts of Halite Solubility Constraints

    NASA Astrophysics Data System (ADS)

    Blanco Martin, L.; Rutqvist, J.; Battistelli, A.; Birkholzer, J. T.

    2015-12-01

    Rock salt is a potential medium for the underground disposal of nuclear waste because it has several assets, such as its ability to creep and heal fractures and its water and gas tightness in the undisturbed state. In this research, we focus on disposal of heat-generating nuclear waste and we consider a generic salt repository with in-drift emplacement of waste packages and crushed salt backfill. As the natural salt creeps, the crushed salt backfill gets progressively compacted and an engineered barrier system is subsequently created [1]. The safety requirements for such a repository impose that long time scales be considered, during which the integrity of the natural and engineered barriers have to be demonstrated. In order to evaluate this long-term integrity, we perform numerical modeling based on state-of-the-art knowledge. Here, we analyze the impacts of halite dissolution and precipitation within the backfill and the host rock. For this purpose, we use an enhanced equation-of-state module of TOUGH2 that properly includes temperature-dependent solubility constraints [2]. We perform coupled thermal-hydraulic-mechanical modeling and we investigate the influence of the mentioned impacts. The TOUGH-FLAC simulator, adapted for large strains and creep, is used [3]. In order to quantify the importance of salt dissolution and precipitation on the effective porosity, permeability, pore pressure, temperature and stress field, we compare numerical results that include or disregard fluids of variable salinity. The sensitivity of the results to some parameters, such as the initial saturation within the backfill, is also addressed. References: [1] Bechthold, W. et al. Backfilling and Sealing of Underground Repositories for Radioactive Waste in Salt (BAMBUS II Project). Report EUR20621 EN: European Atomic Energy Community, 2004. [2] Battistelli A. Improving the treatment of saline brines in EWASG for the simulation of hydrothermal systems. Proceedings, TOUGH Symposium 2012

  7. Background studies in support of a feasibility assessment on the use of copper-base materials for nuclear waste packages in a repository in tuff

    SciTech Connect

    Van Konynenburg, R.A.; Kundig, K.J.A.; Lyman, W.S.; Prager, M.; Meyers, J.R.; Servi, I.S.

    1990-06-01

    This report combines six work units performed in FY`85--86 by the Copper Development Association and the International Copper Research Association under contract with the University of California. The work includes literature surveys and state-of-the-art summaries on several considerations influencing the feasibility of the use of copper-base materials for fabricating high-level nuclear waste packages for the proposed repository in tuff rock at Yucca Mountain, Nevada. The general conclusion from this work was that copper-base materials are viable candidates for inclusion in the materials selection process for this application. 55 refs., 48 figs., 22 tabs.

  8. Review of revegetation practices appropriate for reclamation of the proposed nuclear waste repository at Yucca Mountain, Nevada

    SciTech Connect

    1989-10-01

    The Yucca Mountain site, proposed by US Department of Energy (DOE) as the nation`s first high-level radioactive waste repository is located in Nye County, Nevada, approximately 100 miles northwest of Las Vegas. Yucca Mountain is located in a botanically unique transition zone between the Great Basin and the Mojave Desert. The environment of the proposed repository is influenced by both biotic provinces, and additionally possesses characteristics that are unique unto itself. The purpose of this report is to summarize the existing pertinent data relative to the local environmental constraints that affect reclamation; describe the observations that have been made regarding vegetation reestablishment in the absence of reclamation; and provide special horticultural considerations appropriate for harsh environments such as Yucca Mountain. Further, this report provides specific recommendations to acquire further more specific information needed to refine reclamation prescriptions specifically for Yucca Mountain. Finally, this report describes the time and procedural commitment that must be made to monitor reclamation success. 43 refs., 1 tab.

  9. Use of Geohydrologic Response Functions in the assessment of deep nuclear waste repositories: assessment of effectiveness of geologic isolation systems

    SciTech Connect

    Nelson, R.W.

    1981-05-01

    Geohydrologic Response Functions (GRFs) interrelate the three vital factors needed in the repository decision-making process: the quantity, arrival time, and location of contamination reaching the biosphere. GRFs further focus attention upon two related and additive parameters: the initial delay time and delay spread time. After the principal site selection, the GRFs may be applied to obtain more detailed performance evaluations concerning specific nuclides or waste components, specific results for various types of accidental release, and effects of a variety of contaminant source terms or leach models. The response functions may be applied to consider contaminant reductions and delays through material sorption as well as through a variety of other interactions and effects.

  10. Repository disposal requirements for commercial transuranic wastes (generated without reprocessing)

    SciTech Connect

    Daling, P.M.; Ludwick, J.D.; Mellinger, G.B.; McKee, R.W.

    1986-06-01

    This report forms a preliminary planning basis for disposal of commercial transuranic (TRU) wastes in a geologic repository. Because of the unlikely prospects for commercial spent nuclear fuel reprocessing in the near-term, this report focuses on TRU wastes generated in a once-through nuclear fuel cycle. The four main objectives of this study were to: develop estimates of the current inventories, projected generation rates, and characteristics of commercial TRU wastes; develop proposed acceptance requirements for TRU wastes forms and waste canisters that ensure a safe and effective disposal system; develop certification procedures and processing requirements that ensure that TRU wastes delivered to a repository for disposal meet all applicable waste acceptance requirements; and identify alternative conceptual strategies for treatment and certification of commercial TRU first objective was accomplished through a survey of commercial producers of TRU wastes. The TRU waste acceptance and certification requirements that were developed were based on regulatory requirements, information in the literature, and from similar requirements already established for disposal of defense TRU wastes in the Waste Isolation Pilot Plant (WIPP) which were adapted, where necessary, to disposal of commercial TRU wastes. The results of the TRU waste-producer survey indicated that there were a relatively large number of producers of small quantities of TRU wastes.

  11. Multi-scale groundwater flow modeling during temperate climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden

    NASA Astrophysics Data System (ADS)

    Joyce, Steven; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter

    2014-09-01

    Forsmark in Sweden has been proposed as the site of a geological repository for spent high-level nuclear fuel, to be located at a depth of approximately 470 m in fractured crystalline rock. The safety assessment for the repository has required a multi-disciplinary approach to evaluate the impact of hydrogeological and hydrogeochemical conditions close to the repository and in a wider regional context. Assessing the consequences of potential radionuclide releases requires quantitative site-specific information concerning the details of groundwater flow on the scale of individual waste canister locations (1-10 m) as well as details of groundwater flow and composition on the scale of groundwater pathways between the facility and the surface (500 m to 5 km). The purpose of this article is to provide an illustration of multi-scale modeling techniques and the results obtained when combining aspects of local-scale flows in fractures around a potential contaminant source with regional-scale groundwater flow and transport subject to natural evolution of the system. The approach set out is novel, as it incorporates both different scales of model and different levels of detail, combining discrete fracture network and equivalent continuous porous medium representations of fractured bedrock.

  12. YUCCA MOUNTAIN PROJECT RECOMMENDATION BY THE SECRETARY OF ENERGY REGARDING THE SUITABILITY OF THE YUCCA MOUNTAIN SITE FOR A REPOSITORY UNDER THE NUCLEAR WASTE POLICY ACT OF 1982

    SciTech Connect

    NA

    2002-03-26

    For more than half a century, since nuclear science helped us win World War II and ring in the Atomic Age, scientists have known that !he Nation would need a secure, permanent facility in which to dispose of radioactive wastes. Twenty years ago, when Congress adopted the Nuclear Waste Policy Act of 1982 (NWPA or ''the Act''), it recognized the overwhelming consensus in the scientific community that the best option for such a facility would be a deep underground repository. Fifteen years ago, Congress directed the Secretary of Energy to investigate and recommend to the President whether such a repository could be located safely at Yucca Mountain, Nevada. Since then, our country has spent billions of dollars and millions of hours of research endeavoring to answer this question. I have carefully reviewed the product of this study. In my judgment, it constitutes sound science and shows that a safe repository can be sited there. I also believe that compelling national interests counsel in favor of proceeding with this project. Accordingly, consistent with my responsibilities under the NWPA, today I am recommending that Yucca Mountain be developed as the site for an underground repository for spent fuel and other radioactive wastes. The first consideration in my decision was whether the Yucca Mountain site will safeguard the health and safety of the people, in Nevada and across the country, and will be effective in containing at minimum risk the material it is designed to hold. Substantial evidence shows that it will. Yucca Mountain is far and away the most thoroughly researched site of its kind in the world. It is a geologically stable site, in a closed groundwater basin, isolated on thousands of acres of Federal land, and farther from any metropolitan area than the great majority of less secure, temporary nuclear waste storage sites that exist in the country today. This point bears emphasis. We are not confronting a hypothetical problem. We have a staggering amount of

  13. Illitization within bentonite engineered barrier system in clay repositories for nuclear waste and its effect on the swelling stress: a coupled THMC modeling study

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    Geological repositories for disposal of high-level nuclear waste generally rely on a multi-barrier system to isolate radioactive waste from the biosphere. An engineered barrier system (EBS), which comprises in many design concepts a bentonite backfill, is widely used. Clay formations have been considered as a host rock throughout the world. Illitization, the transformation of smectite to illite, could compromise some beneficiary features of EBS bentonite and clay host rock such as sorption and swelling capacity. It is the major determining factor to establish the maximum design temperature of the repositories because it is believed that illitization could be greatly enhanced at temperatures higher than 100 oC. However, existing experimental and modeling studies on the occurrence of illitization and related performance impacts are not conclusive, in part because the relevant couplings between the thermal, hydrological, chemical, and mechanical (THMC) processes have not been fully represented in the models. Here we present a fully coupled THMC simulation study of a generic nuclear waste repository in a clay formation with a bentonite-backfilled EBS. Two scenarios were simulated for comparison: a case in which the temperature in the bentonite near the waste canister can reach about 200 oC and a case in which the temperature in the bentonite near the waste canister peaks at about 100 oC. The model simulations demonstrate that illitization is in general more significant under higher temperature. However, the quantity of illitization is affected by many chemical factors and therefore varies a great deal. The most important chemical factors are the concentration of K in the pore water as well as the abundance and dissolution rate of K-feldspar. For the particular case and bentonite properties studied, the reduction in swelling stress as a result of chemical changes vary from 2% up to 70% depending on chemical and temperature conditions, and key mechanical parameters. The

  14. Workshop on the source term for radionuclide migration from high-level waste or spent nuclear fuel under realistic repository conditions: proceedings

    SciTech Connect

    Hunter, T.O.; Muller, A.B.

    1985-07-01

    Sixteen papers were presented at the workshop. The fourteen full-length papers included in the proceedings were processed separately. Only abstracts were included for the following two papers: Data Requirements Based on Performance Assessment Analyses of Conceptual Waste Packages in Salt Repositories, and The Potential Effects of Radiation on the Source Term in a Salt Repository. (LM)

  15. Final base case community analysis: Indian Springs, Nevada for the Clark County socioeconomic impact assessment of the proposed high- level nuclear waste repository at Yucca Mountain, Nevada

    SciTech Connect

    1992-06-18

    This document provides a base case description of the rural Clark County community of Indian Springs in anticipation of change associated with the proposed high-level nuclear waste repository at Yucca Mountain. As the community closest to the proposed site, Indian Springs may be seen by site characterization workers, as well as workers associated with later repository phases, as a logical place to live. This report develops and updates information relating to a broad spectrum of socioeconomic variables, thereby providing a `snapshot` or `base case` look at Indian Springs in early 1992. With this as a background, future repository-related developments may be analytically separated from changes brought about by other factors, thus allowing for the assessment of the magnitude of local changes associated with the proposed repository. Given the size of the community, changes that may be considered small in an absolute sense may have relatively large impacts at the local level. Indian Springs is, in many respects, a unique community and a community of contrasts. An unincorporated town, it is a small yet important enclave of workers on large federal projects and home to employees of small- scale businesses and services. It is a rural community, but it is also close to the urbanized Las Vega Valley. It is a desert community, but has good water resources. It is on flat terrain, but it is located within 20 miles of the tallest mountains in Nevada. It is a town in which various interest groups diverge on issues of local importance, but in a sense of community remains an important feature of life. Finally, it has a sociodemographic history of both surface transience and underlying stability. If local land becomes available, Indian Springs has some room for growth but must first consider the historical effects of growth on the town and its desired direction for the future.

  16. Final Systems Development Report for the Clark County Socioeconomic Impact Assessment of the Proposed High-Level Nuclear Waste Repository at Yucca Mountain, NV

    SciTech Connect

    1992-06-18

    The Systems Development Report represents the third major step in the Clark County Socioeconomic Impact Assessment of the Proposed High-Level Nuclear Waste Repository at Yucca Mound Nevada. The first of these steps was to forge a Research Design that would serve as a guide for the overall research process. The second step was the construction of the Base Case, the purpose of which was to describe existing conditions in Clark County in the specified analytic areas of Economic-Demographic/Fiscal, Emergency Planning and Management, Transportation and Sociocultural analysis. The base case description will serve as a basis for assessing changes in these topic areas that might result from the Yucca Mountain project. These changes will be assessed by analyzing conditions with and without repository development in the county. Prior to performing such assessments, however, the snapshot type of data found in the base case must be operationalized or systematized to allow for more dynamic data utilization. In other words, a data system that can be used to analyze the consequences of the introduction of different variables (or variable values) in the Clark County context must be constructed. Such a system must be capable of being updated through subsequent data collection and monitoring efforts to both provide a rolling base case and supply information necessary to construct trend analyses. For example, during the Impact Assessment phase of the study process, the without repository analysis is accomplished by analyzing growth for the county given existing conditions and likely trends. These data are then compared to the with Yucca Mountain project conditions anticipated for the county. Similarly, once the emergency planning management and response needs associated with the repository are described, these needs will be juxtaposed against existing (and various future) capacity(ies) in order to determine the nature and magnitude of impacts in this analytic area. Analogous tasks

  17. Milestones for Selection, Characterization, and Analysis of the Performance of a Repository for Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain.

    SciTech Connect

    Rechard, Robert P.

    2014-02-01

    This report presents a concise history in tabular form of events leading up to site identification in 1978, site selection in 1987, subsequent characterization, and ongoing analysis through 2008 of the performance of a repository for spent nuclear fuel and high-level radioactive waste at Yucca Mountain in southern Nevada. The tabulated events generally occurred in five periods: (1) commitment to mined geologic disposal and identification of sites; (2) site selection and analysis, based on regional geologic characterization through literature and analogous data; (3) feasibility analysis demonstrating calculation procedures and importance of system components, based on rough measures of performance using surface exploration, waste process knowledge, and general laboratory experiments; (4) suitability analysis demonstrating viability of disposal system, based on environment-specific laboratory experiments, in-situ experiments, and underground disposal system characterization; and (5) compliance analysis, based on completed site-specific characterization. Because the relationship is important to understanding the evolution of the Yucca Mountain Project, the tabulation also shows the interaction between four broad categories of political bodies and government agencies/institutions: (a) technical milestones of the implementing institutions, (b) development of the regulatory requirements and related federal policy in laws and court decisions, (c) Presidential and agency directives and decisions, and (d) critiques of the Yucca Mountain Project and pertinent national and world events related to nuclear energy and radioactive waste.

  18. Surveys for desert tortoise on the proposed site of a high-level nuclear waste repository at the Nevada Test Site

    SciTech Connect

    Collins, E.; Sauls, M.L.; O`Farrell, T.P.

    1983-12-31

    The National Waste Terminal Storage Program is a national search for suitable sites to isolate commercial spent nuclear fuel or high-level radioactive waste. The Nevada Nuclear Waste Storage Investigation (NNWSI) managed by the U.S. Department of Energy (DOE), Nevada Operations Office, was initiated to study the suitability of a portion of Yucca Mountain on the DOE`s Nevada Test Site (NTS) as a location for such a repository. EG and G was contracted to provide information concerning the ecosystems encountered on the site. A comprehensive literature survey was conducted to evaluate the status and completeness of the existing biological information for the previously undisturbed area. Site specific studies were begun in 1981 when preliminary field surveys confirmed the presence of the desert tortoise (Gopherus agassizi) within the project area FY82 studies were designed to determine the overall distribution and abundance of the tortoise within the area likely to be impacted by NNWSI activities. The Yucca Mountain area of the Nevada Test Site is situated close to the northern range limit of the desert tortoise. Prior to the 1982 surveys, the desert tortoise was reported from only nine locations on NTS. A known population had been under study in Rock Valley about 25 miles southeast of the project area. However, the distribution and population densities of tortoise in the southwest portion of NTS were virtually unknown. Results of our surveys indicate that desert tortoise can be expected, albeit in small numbers, in a wide range of Mojavean and Transitional habitats.

  19. Actinide Sorption in a Brine/Dolomite Rock System: Evaluating the Degree of Conservatism in Kd Ranges used in Performance Assessment Modeling for the WIPP Nuclear Waste Repository

    NASA Astrophysics Data System (ADS)

    Dittrich, T. M.; Reed, D. T.

    2015-12-01

    The Waste Isolation Pilot Plant (WIPP) near Carlsbad, NM is the only operating nuclear waste repository in the US and has been accepting transuranic (TRU) waste since 1999. The WIPP is located in a salt deposit approximately 650 m below the surface and performance assessment (PA) modeling for a 10,000 year period is required to recertify the operating license with the US EPA every five years. The main pathway of concern for environmental release of radioactivity is a human intrusion caused by drilling into a pressurized brine reservoir below the repository. This could result in the flooding of the repository and subsequent transport in the high transmissivity layer (dolomite-rich Culebra formation) above the waste disposal rooms. We evaluate the degree of conservatism in the estimated sorption partition coefficients (Kds) ranges used in the PA based on an approach developed with granite rock and actinides (Dittrich and Reimus, 2015; Dittrich et al., 2015). Sorption onto the waste storage material (Fe drums) may also play a role in mobile actinide concentrations. We will present (1) a conceptual overview of how Kds are used in the PA model, (2) technical background of the evolution of the ranges and (3) results from batch and column experiments and model predictions for Kds with WIPP dolomite and clays, brine with various actinides, and ligands (e.g., acetate, citrate, EDTA) that could promote transport. The current Kd ranges used in performance models are based on oxidation state and are 5-400, 0.5-10,000, 0.03-200, and 0.03-20 mL g-1 for elements with oxidation states of III, IV, V, and VI, respectively. Based on redox conditions predicted in the brines, possible actinide species include Pu(III), Pu(IV), U(IV), U(VI), Np(IV), Np(V), Am(III), and Th(IV). We will also discuss the challenges of upscaling from lab experiments to field scale predictions, the role of colloids, and the effect of engineered barrier materials (e.g., MgO) on transport conditions. Dittrich

  20. On the importance of coupled THM processes to predict the long-term response of a generic salt repository for high-level nuclear waste

    NASA Astrophysics Data System (ADS)

    Blanco Martin, L.; Rutqvist, J.; Birkholzer, J. T.

    2013-12-01

    Salt is a potential medium for the underground disposal of nuclear waste because it has several assets, in particular its ability to creep and heal fractures generated by excavation and its water and gas tightness in the undisturbed state. In this research, we focus on disposal of heat-generating nuclear waste (such as spent fuel) and we consider a generic salt repository with in-drift emplacement of waste packages and subsequent backfill of the drifts with run-of-mine crushed salt. As the natural salt creeps, the crushed salt backfill gets progressively compacted and an engineered barrier system is subsequently created. In order to evaluate the integrity of the natural and engineered barriers over the long-term, it is important to consider the coupled effects of the thermal, hydraulic and mechanical processes that take place. In particular, the results obtained so far show how the porosity reduction of the crushed salt affects the saturation and pore pressure evolution throughout the repository, both in time and space. Such compaction is induced by the stress and temperature regime within the natural salt. Also, transport properties of the host rock are modified not only by thermo-mechanically and hydraulically-induced damaged processes, but also by healing/sealing of existing fractures. In addition, the THM properties of the backfill evolve towards those of the natural salt during the compaction process. All these changes are based on dedicated laboratory experiments and on theoretical considerations [1-3]. Different scenarios are modeled and compared to evaluate the relevance of different processes from the perspective of effective nuclear waste repositories. The sensitivity of the results to some parameters, such as capillarity, is also addressed. The simulations are conducted using an updated version of the TOUGH2-FLAC3D simulator, which is based on a sequential explicit method to couple flow and geomechanics [4]. A new capability for large strains and creep

  1. Axisymmetric Analysis of Multilayered Thermoelastic Media with Application to a Repository for Heat-Emitting High-Level Nuclear Waste in a Geological Formation

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Datcheva, Maria; Schanz, Tom

    2016-05-01

    Comprehensive analytical solutions to 3D axisymmetric problems for static response of multilayered thermoelastic media subjected to surface loads and containing sources are presented in this study. The solution strategy employs Laplace and Hankel transforms to the field variables. The problem is formulated in cylindrical coordinate system and in this coordinate system vector surface harmonics and generalized propagator matrix are introduced to find the solution for the problem for the behaviour of thermoelastic multilayered media subject to surface loads and containing heat sources. A high-order adaptive Gaussian quadrature method with continued fraction expansions is employed to approximate the integral solutions expressed in terms of semi-infinite Hankel-type integrals. It is the first time to apply the proposed solution method to investigate the behaviour of repository for heat-emitting high-level nuclear waste (HLW) in a geological formation where the HLW can be regarded as a decaying with time point heat source.

  2. Axisymmetric analysis of multilayered thermoelastic media with application to a repository for heat-emitting high-level nuclear waste in a geological formation

    NASA Astrophysics Data System (ADS)

    Yang, Yang; Datcheva, Maria; Schanz, Tom

    2016-08-01

    Comprehensive analytical solutions to 3-D axisymmetric problems for static response of multilayered thermoelastic media subjected to surface loads and containing sources are presented in this study. The solution strategy employs Laplace and Hankel transforms to the field variables. The problem is formulated in cylindrical coordinate system and in this coordinate system vector surface harmonics and generalized propagator matrix are introduced to find the solution for the problem for the behaviour of thermoelastic multilayered media subject to surface loads and containing heat sources. A high-order adaptive Gaussian quadrature method with continued fraction expansions is employed to approximate the integral solutions expressed in terms of semi-infinite Hankel-type integrals. It is the first time to apply the proposed solution method to investigate the behaviour of repository for heat-emitting high-level nuclear waste (HLW) in a geological formation where the HLW can be regarded as a decaying with time point heat source.

  3. Multiple-Code BenchMaek Simulation Stidy of Coupled THMC Processes IN the EXCAVATION DISTURBED ZONE Associated with Geological Nuclear Waste Repositories

    SciTech Connect

    J. Rutqvist; X. Feng; J. Hudson; L. Jing; A. Kobayashi; T. Koyama; P.Pan; H. Lee; M. Rinne; E. Sonnenthal; Y. Yamamoto

    2006-05-08

    An international, multiple-code benchmark test (BMT) study is being conducted within the international DECOVALEX project to analyze coupled thermal, hydrological, mechanical and chemical (THMC) processes in the excavation disturbed zone (EDZ) around emplacement drifts of a nuclear waste repository. This BMT focuses on mechanical responses and long-term chemo-mechanical effects that may lead to changes in mechanical and hydrological properties in the EDZ. This includes time-dependent processes such as creep, and subcritical crack, or healing of fractures that might cause ''weakening'' or ''hardening'' of the rock over the long term. Five research teams are studying this BMT using a wide range of model approaches, including boundary element, finite element, and finite difference, particle mechanics, and elasto-plastic cellular automata methods. This paper describes the definition of the problem and preliminary simulation results for the initial model inception part, in which time dependent effects are not yet included.

  4. On-line remote monitoring of radioactive waste repositories

    NASA Astrophysics Data System (ADS)

    Calì, Claudio; Cosentino, Luigi; Litrico, Pietro; Pappalardo, Alfio; Scirè, Carlotta; Scirè, Sergio; Vecchio, Gianfranco; Finocchiaro, Paolo; Alfieri, Severino; Mariani, Annamaria

    2014-12-01

    A low-cost array of modular sensors for online monitoring of radioactive waste was developed at INFN-LNS. We implemented a new kind of gamma counter, based on Silicon PhotoMultipliers and scintillating fibers, that behaves like a cheap scintillating Geiger-Muller counter. It can be placed in shape of a fine grid around each single waste drum in a repository. Front-end electronics and an FPGA-based counting system were developed to handle the field data, also implementing data transmission, a graphical user interface and a data storage system. A test of four sensors in a real radwaste storage site was performed with promising results. Following the tests an agreement was signed between INFN and Sogin for the joint development and installation of a prototype DMNR (Detector Mesh for Nuclear Repository) system inside the Garigliano radwaste repository in Sessa Aurunca (CE, Italy). Such a development is currently under way, with the installation foreseen within 2014.

  5. Review and analysis of hydrogeologic conditions near the site of a potential nuclear-waste repository, Eddy and Lea counties, New Mexico

    USGS Publications Warehouse

    Mercer, Jerry W.; Orr, Brennon R.

    1977-01-01

    This interim report reviews and summarizes the hydrogeology of rocks associated with the Permian salt beds (Castile and Salado Formations) of Los Medanos area in southeastern New Mexico. The information will be considered, together with other factors, in the preparation of an analysis of the impact of a potential nuclear-waste repository on the environment. Most of the geologic units in and adjacent to the Permian salt deposits are characterized by low permeabilities and highly mineralized water. Sandstone of the Delaware Mountain Group, which underlies the salt, has an average hydraulic conductivity of 0.16 ft/d and an average porosity of 15.65 percent. Flow is north-northeastward toward the margin of the Capitan Limestone, at velocities ranging from 0.0005 to 0.0008 ft/d. The Capitan Limestone, a relatively high yielding limestone-reef aquifer adjacent to the study area, has transmissivity values ranging from 500 sq ft/d to 10,000 sq ft/d and an average hydraulic conductivity of about 5 ft/d. Water movement west of the Pecos River is northeastward in the reef, with discharge at Carlsbad Springs. East of the Pecos River, water moves at very low rates and the direction of movement is uncertain. The Castile and Salado Formations, which might be used to contain the nuclear waste, have a few isolated pockets of brine and gas, but generally transmit little or no ground water. (Woodard-USGS)

  6. Modeling of strongly heat-driven flow processes at a potential high-level nuclear waste repository at Yucca Mountain, Nevada

    SciTech Connect

    Pruess, K.; Tsang, Y.

    1993-01-01

    Two complementary numerical models for analyzing high-level nuclear waste emplacement at Yucca Mountain have been developed. A vertical cross-sectional (X-Z) model permits a realistic representation of hydrogeologic features, such as alternating tilting layers of welded and non-welded tuffs. fault zones, and surface topography. An alternative radially symmetric (R-Z) model is more limited in its ability to describe the hydrogeology of the site, but is better suited to model heat transfer in the host rock. Our models include a comprehensive description of multiphase fluid and heat flow processes, including strong enhancements of vapor diffusion from pore-level phase change effects. The neighborhood of the repository is found to partially dry out from the waste heat. A condensation halo of large liquid saturation forms around the drying zone, from which liquid flows downward at large rates. System response to infiltration from the surface and to ventilation of mined openings is evaluated. The impact of the various flow processes on the waste isolation capabilities of the site is discussed.

  7. Multiple-code simulation study of the long-term EDZ evolution of geological nuclear waste repositories

    SciTech Connect

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

    2008-10-23

    This simulation study shows how widely different model approaches can be adapted to model the evolution of the excavation disturbed zone (EDZ) around a heated nuclear waste emplacement drift in fractured rock. The study includes modeling of coupled thermal-hydrological-mechanical (THM) processes, with simplified consideration of chemical coupling in terms of time-dependent strength degradation or subcritical crack growth. The different model approaches applied in this study include boundary element, finite element, finite difference, particle mechanics, and elastoplastic cellular automata methods. The simulation results indicate that thermally induced differential stresses near the top of the emplacement drift may cause progressive failure and permeability changes during the first 100 years (i.e., after emplacement and drift closure). Moreover, the results indicate that time-dependent mechanical changes may play only a small role during the first 100 years of increasing temperature and thermal stress, whereas such time-dependency is insignificant after peak temperature, because decreasing thermal stress.

  8. Politics of nuclear waste

    SciTech Connect

    Colglazier, E.W. Jr.

    1982-01-01

    In November of 1979, the Program in Science, Technology and Humanism and the Energy Committee of the Aspen Institute organized a conference on resolving the social, political, and institutional conflicts over the permanent siting of radioactive wastes. This book was written as a result of this conference. The chapters provide a comprehensive and up-to-date overview of the governance issues connected with radioactive waste management as well as a sampling of the diverse views of the interested parties. Chapter 1 looks in depth of radioactive waste management in the United States, with special emphasis on the events of the Carter Administration as well as on the issues with which the Reagen administration must deal. Chapter 2 compares waste management policies and programs among the industralized countries. Chapter 3 examines the factional controversies in the last administration and Congress over nuclear waste issues. Chapter 4 examines the complex legal questions involved in the federal-state conflicts over nuclear waste management. Chapter 5 examines the concept of consultation and concurrence from the perspectives of a host state that is a candidate for a repository and an interested state that has special concerns regarding the demonstration of nuclear waste disposal technology. Chapter 6 examines US and European perspectives concerning public participation in nuclear waste management. Chapter 7 discusses propaganda in the issues. The epilogue attempts to assess the prospects for consensus in the United States on national policies for radioactive waste management. All of the chapter in this book should be interpreted as personal assessments. (DP)

  9. Research on uranium deposits as analogies of radioactive waste repositories

    SciTech Connect

    Hardy, C.J.

    1988-01-01

    The disposal of highly radioactive waste deep underground in suitable geological formations is proposed by many countries to protect public health and safety. The study of natural analogies of nuclear waste repositories is one method of validating mathematical models and assuring that a proposed repository site and design will be safe. Since 1981, the AAEC has studied the major uranium deposits in the Alligator Rivers region of the Northern Territory of Australia as natural analogues of radioactive waste repositories. Results have been obtained on the following: (1) the migration of uranium, thorium and radium isotopes, (2) the behavior of naturally occurring levels of selected fission products and transuranium nuclides, e.g. technetium-99, iodine-129 and plutonium-239; (3) the role of specific minerals in retarding migration, and (4) the importance of colloidal material, in the migration of thorium. The AAEC has initiated a wider international project entitled The Alligator Rivers Analogue Project which will enable participating organizations to obtain additional results and to apply them in modeling, planning and regulating waste repositories.

  10. Processing of nuclear waste

    SciTech Connect

    Hennelly, E.J.

    1981-01-01

    The processing of nuclear waste to transform the liquid waste from fuel reprocessing activities is well defined. Most solid waste forms, if they are cooled and contain diluted waste, are compatible with many permanent storage environments. The public acceptance of methods for disposal is being delayed in the US because of the alternatives studies of waste forms and repositories now under way that give the impression of indecision and difficulty for the disposal of HLW. Conservative programs that dilute and cool solid waste are under way in France and Sweden and demonstrate that a solution to the problem is available now. Research and development should be directed toward improving selected methods rather than seeking a best method, which at best, may always be illusory.

  11. Decidedly different: Expert and public views of risks from a radioactive waste repository

    SciTech Connect

    Flynn, J.; Slovic, P.; Mertz, C.K. )

    1993-12-01

    A questionnaire with items that had been used in a national survey of the general public was administered to persons attending an American Nuclear Society meeting. The items asked about risks associated with high-level nuclear waste (HLNW), trust in nuclear-waste program managers, costs and benefits of a repository project, and images of a HLNW repository. The results suggest that nuclear industry experts may have very different opinions from the general public about most of these items and their images of a repository indicate a vastly different conceptual framework within which their opinions are formed. 8 refs., 4 tabs.

  12. Application of Analytical Heat Transfer Models of Multi-layered Natural and Engineered Barriers in Potential High-Level Nuclear Waste Repositories - 12435

    SciTech Connect

    Greenberg, Harris R.; Blink, James A.; Fratoni, Massimiliano; Sutton, Mark; Ross, Amber D.

    2012-07-01

    A combination of transient heat transfer analytical solutions for a finite line source, a series of point sources, and a series of parallel infinite line sources were combined with a quasi-steady-state multi-layered cylindrical solution to simulate the temperature response of a deep geologic radioactive waste repository with multi-layered natural and engineered barriers. This evaluation was performed to provide information to scientists and decision makers to compare candidate geologic media for a repository (crystalline rock [granite], clay, salt, and deep borehole), and to provide input for the future evaluation of the trade-off between pre-emplacement surface storage time, waste package size, and repository footprint. This approach was selected in favor of the finite element solution typically used to analyze the temperature response because it allowed rapid comparison of a large number of alternative disposal options and design configurations. More than 100 combinations of waste form, geologic environment, repository design configuration, and surface storage times were analyzed and compared. The analytical solution approach used to analyze the repository temperature response allowed rapid comparison of a large number of alternative disposal options and design configurations. More than 100 combinations of waste form, geologic environment, repository design configuration, and surface storage times were analyzed and compared. This approach allowed investigation of the sensitivity of the results to combinations of parameters that show that there is much flexibility to be gained in terms of spent fuel management options by varying a few key parameters. This initial analysis used representative design concepts and thermal constraints based on international design concepts, and it also included waste forms representing future fuel cycles with high burnup fuels. Unlike repository designs with large open tunnels and pre-closure ventilation, all of the disposal concepts

  13. Repository waste-handling operations, 1998

    SciTech Connect

    Cottam, A.E.; Connell, L.

    1986-04-01

    The Civilian Radioactive Waste Management Program Mission Plan and the Generic Requirements for a Mined Geologic Disposal System state that beginning in 1998, commercial spent fuel not exceeding 70,000 metric tons of heavy metal, or a quantity of solidified high-level radioactive waste resulting from the reprocessing of such a quantity of spent fuel, will be shipped to a deep geologic repository for permanent storage. The development of a waste-handling system that can process 3000 metric tons of heavy metal annually will require the adoption of a fully automated approach. The safety and minimum exposure of personnel will be the prime goals of the repository waste handling system. A man-out-of-the-loop approach will be used in all operations including the receipt of spent fuel in shipping casks, the inspection and unloading of the spent fuel into automated hot-cell facilities, the disassembly of spent fuel assemblies, the consolidation of fuel rods, and the packaging of fuel rods into heavy-walled site-specific containers. These containers are designed to contain the radionuclides for up to 1000 years. The ability of a repository to handle more than 6000 pressurized water reactor spent-fuel rods per day on a production basis for approximately a 23-year period will require that a systems approach be adopted that combines space-age technology, robotics, and sophisticated automated computerized equipment. New advanced inspection techniques, maintenance by robots, and safety will be key factors in the design, construction, and licensing of a repository waste-handling facility for 1998.

  14. Pools and fluxes of organic matter in a boreal landscape: implications for a safety assessment of a repository for nuclear waste.

    PubMed

    Kumblad, Linda; Söderbäck, Björn; Löfgren, Anders; Lindborg, Tobias; Wijnbladh, Erik; Kautsky, Ulrik

    2006-12-01

    To provide information necessary for a license application for a deep repository for spent nuclear fuel, the Swedish Nuclear Fuel and Waste Management Co is carrying out site investigations, including extensive studies of different parts of the surface ecosystems, at two sites in Sweden. Here we use the output from detailed modeling of the carbon dynamics in the terrestrial, limnic and marine ecosystems to describe and compare major pools and fluxes of organic matter in the Simpevarp area, situated on the southeast coast of Sweden. In this study, organic carbon is used as a proxy for radionuclides incorporated into organic matter. The results show that the largest incorporation of carbon into living tissue occurs in terrestrial catchments. Carbon is accumulated in soil or sediments in all ecosystems, but the carbon pool reaches the highest values in shallow near-land marine basins. The marine basins, especially the outer basins, are dominated by large horizontal water fluxes that transport carbon and any associated contaminants into the Baltic Sea. The results suggest that the near-land shallow marine basins have to be regarded as focal points for accumulation of radionuclides in the Simpevarp area, as they receive a comparatively large amount of carbon as discharge from terrestrial catchments, having a high NPP and a high detrital accumulation in sediments. These focal points may constitute a potential risk for exposure to humans in a future landscape as, due to post-glacial land uplift, previous accumulation bottoms are likely to be used for future agricultural purposes. PMID:17334057

  15. Fabrication development for high-level nuclear waste containers for the tuff repository; Phase 1 final report

    SciTech Connect

    Domian, H.A.; Holbrook, R.L.; LaCount, D.F. |

    1990-09-01

    This final report completes Phase 1 of an engineering study of potential manufacturing processes for the fabrication of containers for the long-term storage of nuclear waste. An extensive literature and industry review was conducted to identify and characterize various processes. A technical specification was prepared using the American Society of Mechanical Engineers Boiler & Pressure Vessel Code (ASME BPVC) to develop the requirements. A complex weighting and evaluation system was devised as a preliminary method to assess the processes. The system takes into account the likelihood and severity of each possible failure mechanism in service and the effects of various processes on the microstructural features. It is concluded that an integral, seamless lower unit of the container made by back extrusion has potential performance advantages but is also very high in cost. A welded construction offers lower cost and may be adequate for the application. Recommendations are made for the processes to be further evaluated in the next phase when mock-up trials will be conducted to address key concerns with various processes and materials before selecting a primary manufacturing process. 43 refs., 26 figs., 34 tabs.

  16. Radioactive waste disposal in simulated peat bog repositories

    SciTech Connect

    Schell, W.R.; Massey, C.D.

    1987-01-01

    The Low Level Radioactive Waste Policy Act of 1980 and the Low Level Radioactive Waste Policy Amendments Act of 1985 have required state governments to be responsible for providing low-level waste (LLW) disposal facilities in their respective areas. Questions are (a) is the technology sufficiently advanced to ensure that radioactive wastes can be stored for 300 to 1000 yr without entering into any uncontrolled area. (b) since actual experience does not exist for nuclear waste disposal over this time period, can the mathematical models developed be tested and verified using unequivocal data. (c) how can the public perception of the problem be addressed and the potential risk assessment of the hazards be communicated. To address the technical problems of nuclear waste disposal in the acid precipitation regions of the Northern Hemisphere, a project was initiated in 1984 to evaluate an alternative method of nuclear waste disposal that may not rely completely on engineered barriers to protect the public. Certain natural biogeochemical systems have been retaining deposited materials since the last Ice Age (12,000 to 15,000 yr). It is the authors belief that the biogeochemical system of wetlands and peat bogs may provide an example of an analogue for a nuclear waste repository system that can be tested and verified over a sufficient time period, at least for the LLW disposal problem.

  17. A Transportation Risk Assessment Tool for Analyzing the Transport of Spent Nuclear Fuel and High-Level Radioactive Waste to the Proposed Yucca Mountain Repository

    SciTech Connect

    Ralph Best; T. Winnard; S. Ross; R. Best

    2001-08-17

    The Yucca Mountain Transportation Database was developed as a data management tool for assembling and integrating data from multiple sources to compile the potential transportation impacts presented in the Draft Environmental Impact Statement for a Geologic Repository for the Disposal of Spent Nuclear Fuel and High-Level Radioactive Waste at Yucca Mountain, Nye County, Nevada (DEIS). The database uses the results from existing models and codes such as RADTRAN, RISKIND, INTERLINE, and HIGHWAY to estimate transportation-related impacts of transporting spent nuclear fuel and high-level radioactive waste from commercial reactors and U. S. Department of Energy (DOE) facilities to Yucca Mountain. The source tables in the database are compendiums of information from many diverse sources including: radionuclide quantities for each waste type; route and route characteristics for rail, legal-weight truck, heavy haul. truck, and barge transport options; state-specific accident and fatality rates for routes selected for analysis; packaging and shipment data by waste type; unit risk factors; the complex behavior of the packaged waste forms in severe transport accidents; and the effects of exposure to radiation or the isotopic specific effects of radionclides should they be released in severe transportation accidents. The database works together with the codes RADTRAN (Neuhauser, et al, 1994) and RISKlND (Yuan, et al, 1995) to calculate incident-free dose and accident risk. For the incident-free transportation scenario, the database uses RADTRAN and RISKIND-generated data to calculate doses to offlink populations, onlink populations, people at stops, crews, inspectors, workers at intermodal transfer stations, guards at overnight stops, and escorts, as well as non-radioactive pollution health effects. For accident scenarios, the database uses RADTRAN-generated data to calculate dose risks based on ingestion, inhalation, resuspension, immersion (cloudshine), and groundshine as

  18. Mountain-Scale Coupled Thermal-Hydrological-Chemical Processes Around the Potential Nuclear Waste Repository at Yucca Mountain

    SciTech Connect

    E. Sonnenthal; C. Haukwa; N. Spycher

    2001-06-04

    The objectives of this study were to evaluate the thermal-hydrological-chemical (THC) effects on flow and geochemistry in the unsaturated zone (UZ) at Yucca Mountain at a mountain scale. The major THC processes important in the UZ are (1) mineral precipitation/dissolution affecting flow and transport to and from the potential repository, and (2) changes in the compositions of gas and liquid that may seep into drifts.

  19. Effects on groundwater flow of abandoned engineered structures for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden

    NASA Astrophysics Data System (ADS)

    Bockgård, Niclas; Marsic, Niko; Follin, Sven

    2014-09-01

    Effects on groundwater flow of abandoned engineered structures in relation to a potential geological repository for spent high-level nuclear fuel in fractured crystalline rock at the Forsmark site, Sweden, are studied by means of numerical modeling. The effects are analyzed by means of particle tracking, and transport-related performance measures are calculated. The impacts of abandoned, partially open repository tunnels are studied for two situations with different climate conditions: a "temperate" climate case with present-day boundary conditions, and a generic future "glacial" climate case with an ice sheet covering the repository. Then, the impact of abandoned open boreholes drilled through the repository is studied for present-day climate conditions. It is found that open repository tunnels and open boreholes can act as easy pathways from repository level to the ground surface; hence, they can attract a considerable proportion of particles released in the model at deposition hole positions within the repository. The changed flow field and flow paths cause some changes in the studied performance measures, i.e., increased flux at the deposition holes and decreased transport lengths and flow-related transport resistances. However, these effects are small and the transport resistance values are still high.

  20. Critical assessment of seismic and geomechanics literature related to a high-level nuclear waste underground repository

    SciTech Connect

    Kana, D.D.; Vanzant, B.W.; Nair, P.K.; Brady, B.H.G.

    1991-06-01

    A comprehensive literature assessment has been conducted to determine the nature and scope of technical information available to characterize the seismic performance of an underground repository and associated facilities. Significant deficiencies were identified in current practices for prediction of seismic response of underground excavations in jointed rock. Conventional analytical methods are based on a continuum representation of the host rock mass. Field observations and laboratory experiments indicate that, in jointed rock, the behavior of the joints controls the overall performance of underground excavations. Further, under repetitive seismic loading, shear displacement develops progressively at block boundaries. Field observations correlating seismicity and groundwater conditions have provided significant information on hydrological response to seismic events. However, lack of a comprehensive model of geohydrological response to seismicity has limited the transportability conclusions from field observations. Based on the literature study, matters requiring further research in relation to the Yucca Mountain repository are identified. The report focuses on understanding seismic processes in fractured tuff, and provides a basis for work on the geohydrologic response of a seismically disturbed rock mass. 220 refs., 43 figs., 11 tabs.

  1. Scenarios constructed for the effects of tectonic processes on the potential nuclear waste repository at Yucca Mountain

    SciTech Connect

    Barr, G.E.; Borns, D.J.; Fridrich, C.

    1996-10-01

    A comprehensive collection of scenarios is presented that connect initiating tectonic events with radionuclide releases by logical and physically possible combinations or sequences of features, events and processes. The initiating tectonic events include both discrete faulting and distributed rock deformation developed through the repository and adjacent to it, as well as earthquake-induced ground motion and changes in tectonic stress at the site. The effects of these tectonic events include impacts on the engineered-barrier system, such as container rupture and failure of repository tunnels. These effects also include a wide range of hydrologic effects such as changes in pathways and flow rates in the unsaturated and saturated zones, changes in the water-table configuration, and in the development of perched-water systems. These scenarios are intended go guide performance-assessment analyses and to assist principal investigators in how essential field, laboratory, and calculational studies are used. This suite of scenarios will help ensure that all important aspects of the system disturbance related to a tectonic scenario are captured in numerical analyses. It also provides a record of all options considered by project analysts to provide documentation required for licensing agreement. The final portion of this report discusses issues remaining to be addressed with respect to tectonic activity. 105 refs.

  2. Environmental program planning for the proposed high-level nuclear waste repository at Yucca Mountain, Nevada; Volume 1

    SciTech Connect

    1987-08-01

    Environmental protection during the course of siting and constructing a repository is mandated by NWPA in conjunction with various phases of repository siting and development. However, DOE has issued no comprehensive, integrated plan for environmental protection. Consequently, it is unclear how DOE will accomplish environmental assessment, monitoring, impact mitigation, and site reclamation. DOE should, therefore, defer further implementation of its current characterization program until a comprehensive environmental protection plan is available. To fulfill its oversight responsibilities the State of Nevada has proposed a comprehensive environmental program for the Yucca Mountain site that includes immediately undertaking studies to establish a 12-month baseline of environmental information at the site; adopting the DOE Site Characterization Plan (SCP) and the engineering design plans it will contain as the basis for defining the impact potential of site characterization activities; using the environmental baseline and the SCP to evaluate the efficacy of the preliminary impact analyses reported by DOE in the EA; using the SCP as the basis for discussions with federal, state, and local regulatory authorities to decide which environmental requirements apply and how they can be complied with; using the SCP, the EA impact review, and the compliance requirements to determine the scope of reclamation measures needed; and developing environmental monitoring and impact mitigation plans based on the EA impact review, compliance requirements, and anticipated reclamation needs.

  3. Natural Analogues - One Way to Help Build Public Confidence in the Predicted Performance of a Mined Geologic Repository for Nuclear Waste

    SciTech Connect

    Stuckless, J. S.

    2002-02-26

    The general public needs to have a way to judge the predicted long-term performance of the potential high-level nuclear waste repository at Yucca Mountain. The applicability and reliability of mathematical models used to make this prediction are neither easily understood nor accepted by the public. Natural analogues can provide the average person with a tool to assess the predicted performance and other scientific conclusions. For example, hydrologists with the Yucca Mountain Project have predicted that most of the water moving through the unsaturated zone at Yucca Mountain, Nevada will move through the host rock and around tunnels. Thus, seepage into tunnels is predicted to be a small percentage of available infiltration. This hypothesis can be tested experimentally and with some quantitative analogues. It can also be tested qualitatively using a variety of analogues such as (1) well-preserved Paleolithic to Neolithic paintings in caves and rock shelters, (2) biological remains preserved in caves and rock shelters, and (3) artifacts and paintings preserved in man-made underground openings. These examples can be found in materials that are generally available to the non-scientific public and can demonstrate the surprising degree of preservation of fragile and easily destroyed materials for very long periods of time within the unsaturated zone.

  4. Progress in evaluation of radionuclide geochemical information developed by DOE high-level nuclear waste repository site projects: Report for April 1986-September 1987

    SciTech Connect

    Meyer, R.E.; Arnold, W.D.; Blencoe, J.G.; O`Kelley, G.D.; Land, J.F.

    1988-02-01

    Experiments were conducted with tuff from the proposed high-level nuclear waste site at Yucca Mountain, Nevada. Batch sorption ratio determinations were conducted for strontium, cesium, uranium, and technetium onto samples of tuff using real and synthetic groundwater J-13. There were no significant differences in sorption ratios in experiments with real and synthetic groundwater. Columns 1 cm in diameter and about 5 cm long were constructed, and experiments were conducted with the objective of correlating the results of batch and the column experiments. The characteristics of the columns were tested by determination of elution curves in J-13 containing tritium and technetium as the TcO{sub 4}{sup -} ion. For strontium and cesium, fairly good correlation between values of the sorption ratio obtained by the two methods was observed. Little or no technetium sorption was observed with either method. The elution peaks obtained with neptunium and uranium were asymmetrical and the shapes were often complex, observations which suggest irreversibilities in the sorption reaction. An experiment was performed to provide information on the compositions of the first groundwaters that will contact waste canisters in a tuff-hosted repository after very near field temperatures have cooled to below 100{degree}C. Synthetic groundwater J-13 was slowly dripped onto a slab of tuff maintained at 95-100{degree}C, and the result was a thin encrustation of solids on the slab as the water evaporated. Fresh J-13 groundwater was then allowed to contact the encrustation in a vessel maintained at 90{degree}C. The principal result of the experiment was a significant loss of calcium and magnesium from the fresh J-13 groundwater.

  5. Repository Waste Package Transporter Shielding Weight Optimization

    SciTech Connect

    C.E. Sanders; Shiaw-Der Su

    2005-02-02

    The Yucca Mountain repository requires the use of a waste package (WP) transporter to transport a WP from a process facility on the surface to the subsurface for underground emplacement. The transporter is a part of the waste emplacement transport systems, which includes a primary locomotive at the front end and a secondary locomotive at the rear end. The overall system with a WP on board weights over 350 metric tons (MT). With the shielding mass constituting approximately one-third of the total system weight, shielding optimization for minimal weight will benefit the overall transport system with reduced axle requirements and improved maneuverability. With a high contact dose rate on the WP external surface and minimal personnel shielding afforded by the WP, the transporter provides radiation shielding to workers during waste emplacement and retrieval operations. This paper presents the design approach and optimization method used in achieving a shielding configuration with minimal weight.

  6. Characterisation and modelling of mixing processes in groundwaters of a potential geological repository for nuclear wastes in crystalline rocks of Sweden.

    PubMed

    Gómez, Javier B; Gimeno, María J; Auqué, Luis F; Acero, Patricia

    2014-01-15

    This paper presents the mixing modelling results for the hydrogeochemical characterisation of groundwaters in the Laxemar area (Sweden). This area is one of the two sites that have been investigated, under the financial patronage of the Swedish Nuclear Waste and Management Co. (SKB), as possible candidates for hosting the proposed repository for the long-term storage of spent nuclear fuel. The classical geochemical modelling, interpreted in the light of the palaeohydrogeological history of the system, has shown that the driving process in the geochemical evolution of this groundwater system is the mixing between four end-member waters: a deep and old saline water, a glacial meltwater, an old marine water, and a meteoric water. In this paper we put the focus on mixing and its effects on the final chemical composition of the groundwaters using a comprehensive methodology that combines principal component analysis with mass balance calculations. This methodology allows us to test several combinations of end member waters and several combinations of compositional variables in order to find optimal solutions in terms of mixing proportions. We have applied this methodology to a dataset of 287 groundwater samples from the Laxemar area collected and analysed by SKB. The best model found uses four conservative elements (Cl, Br, oxygen-18 and deuterium), and computes mixing proportions with respect to three end member waters (saline, glacial and meteoric). Once the first order effect of mixing has been taken into account, water-rock interaction can be used to explain the remaining variability. In this way, the chemistry of each water sample can be obtained by using the mixing proportions for the conservative elements, only affected by mixing, or combining the mixing proportions and the chemical reactions for the non-conservative elements in the system, establishing the basis for predictive calculations. PMID:24070873

  7. Mineralogical characterization of selected shales in support of nuclear waste repository studies: Progress report, October 1987--September 1988

    SciTech Connect

    Lee, S. Y.; Hyder, L. K.; Baxter, P. M.

    1989-07-01

    One objective of the Sedimentary Rock Program at the Oak Ridge National Laboratory has been to examine end-member shales to develop a data base that will aid in evaluations if shales are ever considered as a repository host rock. Five end-member shales were selected for comprehensive characterization: the Chattanooga Shale from Fentress County, Tennessee; the Pierre Shale from Gregory County, South Dakota; the Green River Formation from Garfield County, Colorado; and the Nolichucky Shale and Pumpkin Valley Shale from Roane County, Tennessee. Detailed micromorphological and mineralogical characterizations of the shales were completed by Lee et al. (1987) in ORNL/TM-10567. This report is a supplemental characterization study that was necessary because second batches of the shale samples were needed for additional studies. Selected physical, chemical, and mineralogical properties were determined for the second batches; and their properties were compared with the results from the first batches. Physical characterization indicated that the second-batch and first-batch samples had a noticeable difference in apparent-size distributions but had similar primary-particle-size distributions. There were some differences in chemical composition between the batches, but these differences were not considered important in comparison with the differences among the end-member shales. The results of x-ray diffraction analyses showed that the second batches had mineralogical compositions very similar to the first batches. 9 refs., 9 figs., 4 tabs.

  8. The hydrothermal stability of cement sealing materials in the potential Yucca Mountain high level nuclear waste repository

    SciTech Connect

    Krumhansl, J.L.; Hinkebein, T.E.; Myers, J.

    1991-11-26

    Cementitious materials, together with other materials, are being considered to seal a potential repository at Yucca Mountain. A concern with cementitious materials is the chemical and mineralogic changes that may occur as these materials age while in contact with local ground waters. A combined theoretical and experimental approach was taken to determine the ability to theoretically predict mineralogic changes. The cementitious material selected for study has a relatively low Ca:Si ratio approaching that of the mineral tobermorite. Samples were treated hydrothermally at 200{degrees}C with water similar to that obtained from the J-13 well on the Nevada Test Site. Post-test solutions were analyzed for pH as well as dissolved K, Na, Ca, Al, and Si. Solid phases formed during these experiments were characterized by scanning electron microscopy and X- ray diffraction. These findings were compared with predictions made by the geochemical modeling code EQ3NR/E06. It was generally found that there was good agreement between predicted and experimental results.

  9. Systems study of the feasibility of high-level nuclear waste fractionation for thermal stress control in a geologic repository: appendices

    SciTech Connect

    McKee, R.W.; Elder, H.K.; McCallum, R.F.; Silviera, D.J.; Swanson, J.L.; Wiles, L.E.

    1983-06-01

    This study assesses the benefits and costs of fractionating the cesium and strontium (Cs/Sr) components in commercial high-level waste (HLW) to a separate waste stream for the purpose of reducing geologic-repository thermal stresses in the region of the HLW. The major conclusion is that the Cs/Sr fractionation concept offers the prospect of a substantial total system cost advantage for HLW disposal if reduced HLW package temperatures in a basalt repository are desired. However there is no cost advantage if currently designated maximum design temperatures are acceptable. Aging the HLW for 50 to 100 years can accomplish similar results at equivalent or lower costs. Volume II contains appendices for: (1) thermal analysis supplement; (2) fractionation process experimental results supplement; (3) cost analysis supplement; and (4) radiological risk analysis supplement.

  10. Nuclear Waste Programs semiannual progress report, April--September 1992

    SciTech Connect

    Bates, J.K.; Bradley, C.R.; Buck, E.C.

    1994-05-01

    This document reports on the work done by the Nuclear Waste Programs of the Chemical Technology Division (CMT), Argonne National Laboratory, in the period April--September 1992. In these programs, studies are underway on the performance of waste glass and spent fuel in projected nuclear repository conditions to provide input to the licensing of the nation`s high-level waste repositories.

  11. Nuclear waste programs; Semiannual progress report, October 1991--March 1992

    SciTech Connect

    Bates, J.K.; Bradley, C.R.; Buck, E.C.; Dietz, N.L.; Ebert, W.L.; Emery, J.W.; Feng, X.; Finn, P.A.; Gerding, T.J.; Hoh, J.C.

    1993-11-01

    This document reports on the work done by the Nuclear Waste Programs of the Chemical Technology Division (CMT), Argonne National Laboratory, in the period October 1991-March 1992. In these programs, studies are underway on the performance of waste glass and spent fuel in projected nuclear repository conditions to provide input to the licensing of the nation`s high-level waste repositories

  12. Proposed methodology for completion of scenario analysis for the Basalt Waste Isolation Project. [Assessment of post-closure performance for a proposed repository for high-level nuclear waste

    SciTech Connect

    Roberds, W.J.; Plum, R.J.; Visca, P.J.

    1984-11-01

    This report presents the methodology to complete an assessment of postclosure performance, considering all credible scenarios, including the nominal case, for a proposed repository for high-level nuclear waste at the Hanford Site, Washington State. The methodology consists of defensible techniques for identifying and screening scenarios, and for then assessing the risks associated with each. The results of the scenario analysis are used to comprehensively determine system performance and/or risk for evaluation of compliance with postclosure performance criteria (10 CFR 60 and 40 CFR 191). In addition to describing the proposed methodology, this report reviews available methodologies for scenario analysis, discusses pertinent performance assessment and uncertainty concepts, advises how to implement the methodology (including the organizational requirements and a description of tasks) and recommends how to use the methodology in guiding future site characterization, analysis, and engineered subsystem design work. 36 refs., 24 figs., 1 tab.

  13. Swedish nuclear waste efforts

    SciTech Connect

    Rydberg, J.

    1981-09-01

    After the introduction of a law prohibiting the start-up of any new nuclear power plant until the utility had shown that the waste produced by the plant could be taken care of in an absolutely safe way, the Swedish nuclear utilities in December 1976 embarked on the Nuclear Fuel Safety Project, which in November 1977 presented a first report, Handling of Spent Nuclear Fuel and Final Storage of Vitrified Waste (KBS-I), and in November 1978 a second report, Handling and Final Storage of Unreprocessed Spent Nuclear Fuel (KBS II). These summary reports were supported by 120 technical reports prepared by 450 experts. The project engaged 70 private and governmental institutions at a total cost of US $15 million. The KBS-I and KBS-II reports are summarized in this document, as are also continued waste research efforts carried out by KBS, SKBF, PRAV, ASEA and other Swedish organizations. The KBS reports describe all steps (except reprocessing) in handling chain from removal from a reactor of spent fuel elements until their radioactive waste products are finally disposed of, in canisters, in an underground granite depository. The KBS concept relies on engineered multibarrier systems in combination with final storage in thoroughly investigated stable geologic formations. This report also briefly describes other activities carried out by the nuclear industry, namely, the construction of a central storage facility for spent fuel elements (to be in operation by 1985), a repository for reactor waste (to be in operation by 1988), and an intermediate storage facility for vitrified high-level waste (to be in operation by 1990). The R and D activities are updated to September 1981.

  14. Evaluation of tuff as a medium for a nuclear waste repository: interim status report on the properties of tuff

    SciTech Connect

    Johnstone, J.K.; Wolfsberg, K.

    1980-07-01

    This report is the second in a series of summary briefings to the National Academy of Science`s (NAS) Committee on Radioactive Waste Management dealing with feasibility of disposal of heat-producing radioactive waste in silicic tuff. The interim status of studies of tuff properties determined on samples obtained from Yucca Mountain and Rainier Mesa (G-tunnel) located on the Nevada Test Site (NTS) are discussed. In particular, progress is described on resolving issues identified during the first briefing to the NAS which include behavior of water in tuff when heated, the effect of the presence or absence of water and joints on the thermal/physical properties of tuff and the detailed/complex sorptive properties of highly altered and unaltered tuff. Initial correlations of thermal/physical and sorptive properties with the highly variable porosity and mineralogy are described. Three in-situ, at-depth field experiments, one nearly completed and two just getting underway are described. In particular, the current status of mineralogy and petrology, geochemistry, thermal and mechanical, radiation effects and water behavior studies are described. The goals and initial results of a Mine Design Working Group are discussed. Regional factors such as seismicity, volcanism and hydrology are not discussed.

  15. A federalist strategy for nuclear waste management.

    PubMed

    Lee, K N

    1980-05-16

    The federal government plans to rely on a policy of "consultation and concurrence" with state governments in developing nuclear waste repositories. The weaknesses of the concurrence approach are analyzed, and an alternative institutional framework for locating a waste repository is proposed: a siting jury that provides representation for state and local interests, while maintaining a high level of technical review. The proposal could be tested in the siting of away-from-reactor storage facilities for spent nuclear fuel. PMID:17771087

  16. Radiation-Induced Defects in Kaolinite as Tracers of Past Occurrence of Radionuclides in a Natural Analogue of High Level Nuclear Waste Repository

    NASA Astrophysics Data System (ADS)

    Allard, T.; Fourdrin, C.; Calas, G.

    2007-05-01

    Understanding the processes controlling migrations of radioelements at the Earth's surface is an important issue for the long-term safety assessment of high level nuclear waste repositories (HLNWR). Evidence of past occurrence and transfer of radionuclides can be found using radiation-induced defects in minerals. Clay minerals are particularly relevant because of their widespread occurrence at the Earth's surface and their finely divided nature which provides high contact area with radioactive fluids. Owing to its sensitivity to radiations, kaolinite can be used as natural, in situ dosimeter. Kaolinite is known to contain radiation-induced defects which are detected by Electron Paramagnetic Resonance. They are differentiated by their nature, their production kinetics and their thermal stability. One of these defects is stable at the scale of geological periods and provides a record of past radionuclide occurrence. Based on artificial irradiations, a methodology has been subsequently proposed to determine paleodose cumulated by kaolinite since its formation. The paleodose can be used to derive equivalent radioelement concentrations, provided that the age of kaolinite formation can be constrained. This allows quantitative reconstruction of past transfers of radioelements in natural systems. An example is given for the Nopal I U-deposit (Chihuahua, Mexico), hosted in hydrothermally altered volcanic tufs and considered as analogue of the Yucca Mountain site. The paleodoses experienced by kaolinites were determined from the concentration of defects and dosimetry parameters of experimental irradiations. Using few geochemical assumption, a equivalent U-content responsible for defects in kaolinite was calculated from the paleodose, a dose rate balance and model ages of kaolinites constrained by tectonic phases. In a former study, the ages were assumptions derived from regional tectonic events. In thepresent study, ages of mineralization events are measured from U

  17. Milestones for Selection Characterization and Analysis of the Performance of a Repository for Spent Nuclear Fuel and HIh-Level Radioactive Waste at Yucca Mountain.

    SciTech Connect

    Rechard, Robert P.

    2015-02-01

    This report presents a concise history in tabular form of events leading up to site identification in 1978, site selection in 1987, subsequent characterization, and ongoing analysis throu gh 2009 of the performance of a repository for spent nuclear fuel and high - level radi oactive waste at Yucca Mou ntain in southern Nevada. The tabulated events generally occurred in five periods: (1) commitment to mined geologic disposal and identification of sites; (2) site selection and analysis, based on regional geologic characterization through literature and an alogous data; (3) feasibility analysis demonstrating calculation procedures and importance of system components, based on rough measures of performance using surface exploration, waste process knowledge, and general laboratory experiments; (4) suitability analysis demonstrating viability of disposal system, based on environment - specific laboratory experiments, in - situ experiments, and underground disposal system characterization; and (5) compliance analysis, based on completed site - specific characterization . The current sixth period beyond 2010 represents a new effort to set waste management policy in the United States. Because the relationship is important to understanding the evolution of the Yucca Mountain Project , the tabulation also shows the interaction between the policy realm and technical realm using four broad categories of events : (a ) R egulatory requirements and related federal policy in laws and court decisions, (c ) Presidential and agency directives, (c) technical milestones of implemen ting institutions, and (d ) critiques of the Yucca Mountai n P roject and pertinent national and world events related to nuclear energy and radioactive waste. Preface The historical progression of technical milestones for the Yucca Mountain Project was originally developed for 10 journal articles in a special issue of Reliability Engineering System Safe ty on the performance assessment for the Yucca Mountain

  18. Characteristics of potential repository wastes. Volume 1

    SciTech Connect

    Not Available

    1992-07-01

    This document, and its associated appendices and microcomputer (PC) data bases, constitutes the reference OCRWM data base of physical and radiological characteristics data of radioactive wastes. This Characteristics Data Base (CDB) system includes data on spent nuclear fuel and high-level waste (HLW), which clearly require geologic disposal, and other wastes which may require long-term isolation, such as sealed radioisotope sources. The data base system was developed for OCRWM by the CDB Project at Oak Ridge National Laboratory. Various principal or official sources of these data provided primary information to the CDB Project which then used the ORIGEN2 computer code to calculate radiological properties. The data have been qualified by an OCRWM-sponsored peer review as suitable for quality-affecting work meeting the requirements of OCRWM`s Quality Assurance Program. The wastes characterized in this report include: light-water reactor (LWR) spent fuel and immobilized HLW.

  19. Waste package/repository impact study: Final report

    SciTech Connect

    Not Available

    1985-09-01

    The Waste Package/Repository Impact Study was conducted to evaluate the feasibility of using the current reference salt waste package in the salt repository conceptual design. All elements of the repository that may impact waste package parameters, i.e., (size, weight, heat load) were evaluated. The repository elements considered included waste hoist feasibility, transporter and emplacement machine feasibility, subsurface entry dimensions, feasibility of emplacement configuration, and temperature limits. The evaluations are discussed in detail with supplemental technical data included in Appendices to this report, as appropriate. Results and conclusions of the evaluations are discussed in light of the acceptability of the current reference waste package as the basis for salt conceptual design. Finally, recommendations are made relative to the salt project position on the application of the reference waste package as a basis for future design activities. 31 refs., 11 figs., 11 tabs.

  20. Case for retrievable high-level nuclear waste disposal

    USGS Publications Warehouse

    Roseboom, Eugene H., Jr.

    1994-01-01

    Plans for the nation's first high-level nuclear waste repository have called for permanently closing and sealing the repository soon after it is filled. However, the hydrologic environment of the proposed site at Yucca Mountain, Nevada, should allow the repository to be kept open and the waste retrievable indefinitely. This would allow direct monitoring of the repository and maintain the options for future generations to improve upon the disposal methods or use the uranium in the spent fuel as an energy resource.

  1. Characteristics of potential repository wastes. Volume 2

    SciTech Connect

    Not Available

    1992-07-01

    The LWR spent fuels discussed in Volume 1 of this report comprise about 99% of all domestic non-reprocessed spent fuel. In this report we discuss other types of spent fuels which, although small in relative quantity, consist of a number of diverse types, sizes, and compositions. Many of these fuels are candidates for repository disposal. Some non-LWR spent fuels are currently reprocessed or are scheduled for reprocessing in DOE facilities at the Savannah River Site, Hanford Site, and the Idaho National Engineering Laboratory. It appears likely that the reprocessing of fuels that have been reprocessed in the past will continue and that the resulting high-level wastes will become part of defense HLW. However, it is not entirely clear in some cases whether a given fuel will be reprocessed, especially in cases where pretreatment may be needed before reprocessing, or where the enrichment is not high enough to make reprocessing attractive. Some fuels may be canistered, while others may require special means of disposal. The major categories covered in this chapter include HTGR spent fuel from the Fort St. Vrain and Peach Bottom-1 reactors, research and test reactor fuels, and miscellaneous fuels, and wastes generated from the decommissioning of facilities.

  2. For Sale: Nuclear Waste Sites--Anyone Buying?

    ERIC Educational Resources Information Center

    Hancock, Don

    1992-01-01

    Explores why the United States Nuclear Waste Program has been unable to find a volunteer state to host either a nuclear waste repository or monitored retrieval storage facility. Discusses the Department of Energy's plans for Nevada's Yucca Mountain as a repository and state and tribal responses to the plan. (21 references) (MCO)

  3. Groundwater flow modeling of periods with periglacial and glacial climate conditions for the safety assessment of the proposed high-level nuclear waste repository site at Forsmark, Sweden

    NASA Astrophysics Data System (ADS)

    Vidstrand, Patrik; Follin, Sven; Selroos, Jan-Olof; Näslund, Jens-Ove

    2014-09-01

    The impact of periglacial and glacial climate conditions on groundwater flow in fractured crystalline rock is studied by means of groundwater flow modeling of the Forsmark site, which was recently proposed as a repository site for the disposal of spent high-level nuclear fuel in Sweden. The employed model uses a thermal-hydraulically coupled approach for permafrost modeling and discusses changes in groundwater flow implied by the climate conditions found over northern Europe at different times during the last glacial cycle (Weichselian glaciation). It is concluded that discharge of particles released at repository depth occurs very close to the ice-sheet margin in the absence of permafrost. If permafrost is included, the greater part discharges into taliks in the periglacial area. During a glacial cycle, hydraulic gradients at repository depth reach their maximum values when the ice-sheet margin passes over the site; at this time, also, the interface between fresh and saline waters is distorted the most. The combined effect of advances and retreats during several glaciations has not been studied in the present work; however, the results indicate that hydrochemical conditions at depth in the groundwater flow model are almost restored after a single event of ice-sheet advance and retreat.

  4. Alternative configurations for the waste-handling building at the Yucca Mountain Repository

    SciTech Connect

    1990-08-01

    Two alternative configurations of the waste-handling building have been developed for the proposed nuclear waste repository in tuff at Yucca Mountain, Nevada. One configuration is based on criteria and assumptions used in Case 2 (no monitored retrievable storage facility, no consolidation), and the other configuration is based on criteria and assumptions used in Case 5 (consolidation at the monitored retrievable storage facility) of the Monitored Retrievable Storage System Study for the Repository. Desirable waste-handling design concepts have been selected and are included in these configurations. For each configuration, general arrangement drawings, plot plans, block flow diagrams, and timeline diagrams are prepared.

  5. Numerical study of the THM effects on the near-field safety of ahypothetical nuclear waste repository - BMT1 of the DECOVALEX IIIproject. Part 3: Effects of THM coupling in sparsely fracturedrocks

    SciTech Connect

    Rutqvist, J.; Chijimatsu, M.; Jing, L.; Millard, A.; Nguyen,T.S.; Rejeb, A.; Sugita, Y.; Tsang, C.F.

    2004-09-09

    BENCHPAR project, the impact of thermal-hydrological-mechanical (THM) couplings on the performance of a bentonite-back-filled nuclear waste repository in near-field crystalline rocks is evaluated in a Bench-Mark Test problem (BMT1) and the results are presented in a series of three companion papers in this issue. This is the third paper with focus on the effects of THM processes at a repository located in a sparsely fractured rock. Several independent coupled THM analyses presented in this paper show that THM couplings have the most significant impact on the mechanical stress evolution, which is important for repository design, construction and post-closure monitoring considerations. The results show that the stress evolution in the bentonite-back-filled excavations and the surrounding rock depends on the post-closure evolution of both fields of temperature and fluid pressure.It is further shown that the time required to full resaturation may play an important role for the mechanical integrity of the repository drifts.In this sense, the presence of hydraulically conducting fractures in the near-field rock might actually improve the mechanical performance of the repository. Hydraulically conducting fractures in the near-field rocks enhances the water supply to the buffers/back-fills, which promotes a more timely process of resaturation and development of swelling pressures in the back-fill, thus provides timely confining stress and support to the rock walls. In one particular case simulated in this study, it was shown that failure in the drift walls could be prevented if the compressive stresses in back-fill were fully developed within 50 years,which is when thermally induced rock strain begins to create high differential (failure-prone) stresses in the near-field rocks.

  6. Building of multilevel stakeholder consensus in radioactive waste repository siting

    SciTech Connect

    Dreimanis, A.

    2007-07-01

    This report considers the problem of multilevel consensus building for siting and construction of shared multinational/regional repositories for radioactive waste (RW) deep disposal. In the siting of a multinational repository there appears an essential innovative component of stakeholder consensus building, namely: to reach consent - political, social, economic, ecological - among international partners, in addition to solving the whole set of intra-national consensus building items. An entire partnering country is considered as a higher-level stakeholder - the national stakeholder, represented by the national government, being faced to simultaneous seeking an upward (international) and a downward (intra-national) consensus in a psychologically stressed environment, possibly being characterized by diverse political, economic and social interests. The following theses as a possible interdisciplinary approach towards building of shared understanding and stakeholder consensus on the international scale of RW disposal are forwarded and developed: a) building of international stakeholder consensus would be promoted by activating and diversifying on the international scale multilateral interactions between intra- and international stakeholders, including web-based networks of the RW disposal site investigations and decision-making, as well as networks for international cooperation among government authorities in nuclear safety, b) gradual progress in intergovernmental consensus and reaching multilateral agreements on shared deep repositories will be the result of democratic dialogue, via observing the whole set of various interests and common resolving of emerged controversies by using advanced synergetic approaches of conflict resolution, c) cross-cultural thinking and world perception, mental flexibility, creativity and knowledge are considered as basic prerogatives for gaining a higher level of mutual understanding and consensus for seeking further consensus, for

  7. Feasibility assessment of copper-base waste package container materials in a repository in basalt

    SciTech Connect

    Anantatmula, R.P.

    1985-09-01

    The results of FY 1985 corrosion testing and design development efforts are presented in support of a feasibility assessment of copper-base materials for use in waste container applications for a proposed nuclear waste repository in basalt. Two materials were included in the assessment activities: (1) high purity copper (UNS C10200), and (2) Cupronickel 90-10 (UNS C70600). Testing activities during FY 1985 included general corrosion, pitting corrosion, and environmentally assisted cracking studies. The FY 1985 waste package design studies considered consolidated spent nuclear fuel and West Valley high-level waste. 6 refs., 5 figs., 2 tabs.

  8. Assessing microbiologically induced corrosion of waste package materials in the Yucca Mountain repository

    SciTech Connect

    Horn, J. M., LLNL

    1998-01-01

    The contribution of bacterial activities to corrosion of nuclear waste package materials must be determined to predict the adequacy of containment for a potential nuclear waste repository at Yucca Mountain (YM), NV. The program to evaluate potential microbially induced corrosion (MIC) of candidate waste container materials includes characterization of bacteria in the post-construction YM environment, determination of their required growth conditions and growth rates, quantitative assessment of the biochemical contribution to metal corrosion, and evaluation of overall MIC rates on candidate waste package materials.

  9. Parameter sensitivity studies of selected components of the Waste Isolation Pilot Plant repository/shaft system

    SciTech Connect

    Rechard, R.P. ); Beyeler, W.; Schreiber, J.D. ); McCurley, R.D.; Rudeen, D.K.; Bean, J.E. )

    1990-03-01

    This status report presents preliminary analyses of flow through the rooms, drifts, seals, and shafts of the Waste Isolation Pilot Plant (WIPP). The purpose of these analyses is to evaluate the importance of various components and parameters of the transuranic waste repository. These analyses are presented to show the current status of repository/shaft system modeling, and to provide input for evaluating proposed engineered modifications to the waste and rooms to ensure compliance with the Environmental Protection Agency's Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Waste. Detailed descriptions are given for nine computational models of the WIPP repository for either undisturbed or human intrusion conditions. Some models are refined versions of earlier models; others include rudimentary studies of an additional phenomenon, flow of generated gas. The models of an undisturbed repository substantiated the results of earlier models by showing that no waste leaves the vicinity of the disposal area in 10,000 yr. The models that studies gas flow agreed with this position; however, the models are too rudimentary to permit conclusive statements. The five models of the human intrusion event explored the importance of parameters that influence the flow of brine through the waste, establishing a base for understanding the behavior of the waste disposal rooms, drifts,and interbeds in the host rock. 63 refs., 92 figs., 29 tabs.

  10. Thermal - Hydraulic Behavior of Unsaturated Bentonite and Sand-Bentonite Material as Seal for Nuclear Waste Repository: Numerical Simulation of Column Experiments

    NASA Astrophysics Data System (ADS)

    Ballarini, E.; Graupner, B.; Bauer, S.

    2015-12-01

    For deep geological repositories of high-level radioactive waste (HLRW), bentonite and sand bentonite mixtures are investigated as buffer materials to form a a sealing layer. This sealing layer surrounds the canisters and experiences an initial drying due to the heat produced by HLRW and a successive re-saturation with fluid from the host rock. These complex thermal, hydraulic and mechanical processes interact and were investigated in laboratory column experiments using MX-80 clay pellets as well as a mixture of 35% sand and 65% bentonite. The aim of this study is to both understand the individual processes taking place in the buffer materials and to identify the key physical parameters that determine the material behavior under heating and hydrating conditions. For this end, detailed and process-oriented numerical modelling was applied to the experiments, simulating heat transport, multiphase flow and mechanical effects from swelling. For both columns, the same set of parameters was assigned to the experimental set-up (i.e. insulation, heater and hydration system), while the parameters of the buffer material were adapted during model calibration. A good fit between model results and data was achieved for temperature, relative humidity, water intake and swelling pressure, thus explaining the material behavior. The key variables identified by the model are the permeability and relative permeability, the water retention curve and the thermal conductivity of the buffer material. The different hydraulic and thermal behavior of the two buffer materials observed in the laboratory observations was well reproduced by the numerical model.

  11. Investigations of natural groundwater hazards at the proposed Yucca Mountain high level nuclear waste repository. Part A: Geology at Yucca Mountain. Part B: Modeling of hydro-tectonic phenomena relevant to Yucca Mountain. Annual report - Nevada

    SciTech Connect

    Szymanski, J.S.; Schluter, C.M.; Livingston, D.E.

    1993-05-01

    This document is an annual report describing investigations of natural groundwater hazards at the proposed Yucca Mountain, Nevada High-Level Nuclear Waste Repository.This document describes research studies of the origin of near surface calcite/silica deposits at Yucca Mountain. The origin of these deposits is controversial and the authors have extended and strengthened the basis of their arguments for epigenetic, metasomatic alteration of the tuffs at Yucca Mountain. This report includes stratigraphic, mineralogical, and geochronological information along with geochemical data to support the conclusions described by Livingston and Szymanski, and others. As part of their first annual report, they take this opportunity to clarify the technical basis of their concerns and summarize the critical geological field evidence and related information. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  12. Radionuclide transport behavior in a generic geological radioactive waste repository.

    PubMed

    Bianchi, Marco; Liu, Hui-Hai; Birkholzer, Jens T

    2015-01-01

    We performed numerical simulations of groundwater flow and radionuclide transport to study the influence of several factors, including the ambient hydraulic gradient, groundwater pressure anomalies, and the properties of the excavation damaged zone (EDZ), on the prevailing transport mechanism (i.e., advection or molecular diffusion) in a generic nuclear waste repository within a clay-rich geological formation. By comparing simulation results, we show that the EDZ plays a major role as a preferential flowpath for radionuclide transport. When the EDZ is not taken into account, transport is dominated by molecular diffusion in almost the totality of the simulated domain, and transport velocity is about 40% slower. Modeling results also show that a reduction in hydraulic gradient leads to a greater predominance of diffusive transport, slowing down radionuclide transport by about 30% with respect to a scenario assuming a unit gradient. In addition, inward flow caused by negative pressure anomalies in the clay-rich formation further reduces transport velocity, enhancing the ability of the geological barrier to contain the radioactive waste. On the other hand, local high gradients associated with positive pressure anomalies can speed up radionuclide transport with respect to steady-state flow systems having the same regional hydraulic gradients. Transport behavior was also found to be sensitive to both geometrical and hydrogeological parameters of the EDZ. Results from this work can provide useful knowledge toward correctly assessing the post-closure safety of a geological disposal system. PMID:24571606

  13. Nuclear Waste Disposal

    SciTech Connect

    Gee, Glendon W.; Meyer, Philip D.; Ward, Andy L.

    2005-01-12

    Nuclear wastes are by-products of nuclear weapons production and nuclear power generation, plus residuals of radioactive materials used by industry, medicine, agriculture, and academia. Their distinctive nature and potential hazard make nuclear wastes not only the most dangerous waste ever created by mankind, but also one of the most controversial and regulated with respect to disposal. Nuclear waste issues, related to uncertainties in geologic disposal and long-term protection, combined with potential misuse by terrorist groups, have created uneasiness and fear in the general public and remain stumbling blocks for further development of a nuclear industry in a world that may soon be facing a global energy crisis.

  14. Waterproofing and Strengthening Volcanic Tuff in Waste Repositories

    SciTech Connect

    Carter, E.E.; Carter, P.E.; Cooper, D.C.

    2008-07-01

    Waste repositories from surface trenches and shafts at Los Alamos to drilled tunnels at Yucca Mountain are being built in volcanic Tuff, a soft compacted material that is permeable to water and air. US Department of Energy documents on repository design identify the primary design goal of 'preventing water from reaching the waste canisters, dissolving the canisters and carrying the radioactive waste particles away from the repository'. Designers expect to achieve this by use of multiple barriers along with careful placement of the repository both well above the water table and well above the ground level in a mountain. Though repositories are located in areas that have a historically dry climate to minimize the impact of rainfall infiltration, global warming phenomena may have the potential to alter regional climate patterns - potentially leading to higher infiltration rates. Conventional methods of sealing fractures within volcanic tuff may not be sufficiently robust or long lived to isolate a repository shaft from water for the required duration. A new grouting technology based on molten wax shows significant promise for producing the kind of long term sealing performance required. Molten wax is capable of permeating a significant distance through volcanic tuff, as well as sealing fractures by permeation that is thermally dependent instead of chemically or time dependent. The wax wicks into and saturates tuff even if no fractures are present, but penetrates and fills only the heated area. Heated portions of the rock fill like a vessel. The taffy-like wax has been shown to waterproof the tuff, and significantly increase its resistance to fracture. This wax was used in 2004 for grouting of buried radioactive beryllium waste at the Idaho National Laboratory, chiefly to stop the water based corrosion reactions of the waste. The thermoplastic material contains no water and does not dry out or change with age. Recent studies indicate that this kind of wax material may

  15. Might underground waste repositories blow up?

    SciTech Connect

    Hippel, F. von

    1996-03-01

    Some writers have presented possible scenarios in which a subcritical underground deposit of plutonium or other fissile material might be changed into a critical configuration. The underground criticalities that occurred in Gabon some 1.7 billion years ago in deposits of natural uranium is cited. Other scientists assert that it is virtually impossible that such a configuration could develop in an underground repository. The author presents the pros and cons of these views. 5 refs.

  16. Source terms for analysis of accidents at a high level waste repository

    SciTech Connect

    Mubayi, V.; Davis, R.E.; Youngblood, R.

    1989-01-01

    This paper describes an approach to identifying source terms from possible accidents during the preclosure phase of a high-level nuclear waste repository. A review of the literature on repository safety analyses indicated that source term estimation is in a preliminary stage, largely based on judgement-based scoping analyses. The approach developed here was to partition the accident space into domains defined by certain threshold values of temperature and impact energy density which may arise in potential accidents and specify release fractions of various radionuclides, present in the waste form, in each domain. Along with a more quantitative understanding of accident phenomenology, this approach should help in achieving a clearer perspective on scenarios important to preclosure safety assessments of geologic repositories. 18 refs., 3 tabs.

  17. Groundwater occurrence and the dissolution of salt at the WIPP Radioactive Waste Repository Site

    NASA Astrophysics Data System (ADS)

    Chaturvedi, Lokesh; Rehfeldt, Kenneth

    1984-04-01

    The Waste Isolation Pilot Plant (WIPP), located about 25 miles east of Carlsbad, in southeastern New Mexico, is slated to be the first deep geologic repository for permanent disposal of radioactive wastes in the United States. The repository will be located in bedded salt of Permian (225 m.y. B.P.) age, at a depth of 655 m below the ground surface. The present mission of WIPP calls for a permanent disposal of approximately 170,000 cubic meters of defense transuranic (TRU) wastes and for temporary, retrievable emplacement of 4.25 cubic meters of experimental high level wastes. The site will not be licensed by the Nuclear Regulatory Commission (NRC) but will comply with the Environmental Protection Agency (EPA) standards and all other federal and state regulations.

  18. Reliable predictions of waste performance in a geologic repository

    SciTech Connect

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

    1985-08-01

    Establishing reliable estimates of long-term performance of a waste repository requires emphasis upon valid theories to predict performance. Predicting rates that radionuclides are released from waste packages cannot rest upon empirical extrapolations of laboratory leach data. Reliable predictions can be based on simple bounding theoretical models, such as solubility-limited bulk-flow, if the assumed parameters are reliably known or defensibly conservative. Wherever possible, performance analysis should proceed beyond simple bounding calculations to obtain more realistic - and usually more favorable - estimates of expected performance. Desire for greater realism must be balanced against increasing uncertainties in prediction and loss of reliability. Theoretical predictions of release rate based on mass-transfer analysis are bounding and the theory can be verified. Postulated repository analogues to simulate laboratory leach experiments introduce arbitrary and fictitious repository parameters and are shown not to agree with well-established theory. 34 refs., 3 figs., 2 tabs.

  19. Thermodynamic Properties of Magnesium Chloride Hydroxide Hydrate (Mg3Cl(OH)5:4H2O, Phase 5), and Its importance to Nuclear Waste Isolation in Geological Repositories in Salt Formations

    NASA Astrophysics Data System (ADS)

    Xiong, Y.; Deng, H.; Nemer, M. B.; Johnsen, S.

    2009-12-01

    -1, respectively. Phase 5, and its similar phase, phase 3 (Mg2Cl(OH)3:4H2O), could have a significant role in influencing the geochemical conditions in geological repositories for nuclear waste in salt formations where MgO or brucite is employed as engineered barriers, when Na-Mg-Cl dominated brines react with MgO or brucite. Based on our solubility constant for phase 5 in combination with the literature value for phase 3, we predict that the composition for the invariant point of phase 5 and phase 3 would be mMg = 1.70 and pmH = 8.93 in the Mg-Cl binary system. The recent WIPP Compliance Recertification Application PA Baseline Calculations indicate that phase 5 instead of phase 3 is indeed a stable phase when GWB equilibrates with actinide-source-term phases, brucite, magnesium carbonates, halite and anhydrite. 1. This research is funded by WIPP programs administered by the U.S. Department of Energy. 2. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

  20. Comparison of the Microbial Community Composition at Yucca Mountain and Laboratory Test Nuclear Repository Environments

    SciTech Connect

    Horn, J; Carrillo, C; Dias, V

    2002-10-09

    The microbiological community structure within a proposed nuclear waste repository at Yucca Mountain (YM), NV was determined. Microbial growth from collected rock was detected using simulated ground water as a growth medium, with or without amendment of a carbon source. Grown isolates were identified by 16s ribosomal DNA (rDNA) sequence analysis. A more complete compositional analysis of the microbial community located at the proposed nuclear waste repository site was performed using environmental DNA isolation and subsequent identification of amplified 16s rDNA genes. Concurrently, a series of corrosion testing tanks that simulate the evolution of anticipated environmental conditions within the proposed repository have been subjected to the same type of analyses.

  1. Nuclear waste forms for actinides

    PubMed Central

    Ewing, Rodney C.

    1999-01-01

    The disposition of actinides, most recently 239Pu from dismantled nuclear weapons, requires effective containment of waste generated by the nuclear fuel cycle. Because actinides (e.g., 239Pu and 237Np) are long-lived, they have a major impact on risk assessments of geologic repositories. Thus, demonstrable, long-term chemical and mechanical durability are essential properties of waste forms for the immobilization of actinides. Mineralogic and geologic studies provide excellent candidate phases for immobilization and a unique database that cannot be duplicated by a purely materials science approach. The “mineralogic approach” is illustrated by a discussion of zircon as a phase for the immobilization of excess weapons plutonium. PMID:10097054

  2. Viability Assessment of a Repository at Yucca Mountain. Volume 2: Preliminary Design Concept for the Repository and Waste Package

    SciTech Connect

    1998-12-01

    This volume describes the major design features of the Monitored Geologic Repository. This document is not intended to provide an exhaustive, detailed description of the repository design. Rather, this document summarizes the major systems and primary elements of the design that are radiologically significant, and references the specific technical documents and design analyses wherein the details can be found. Not all portions of the design are at the same level of completeness. Highest priority has been given to assigning resources to advance the design of the Monitored Geologic Repository features that are important to radiological safety and/or waste isolation and for which there is no NRC licensing precedent. Those features that are important to radiological safety and/or waste isolation, but for which there is an NRC precedent, receive second priority. Systems and features that have no impact on radiological safety or waste isolation receive the lowest priority. This prioritization process, referred to as binning, is discussed in more detail in Section 2.3. Not every subject discussed in this volume is given equal treatment with regard to the level of detail provided. For example, less detail is provided for the surface facility design than for the subsurface and waste package designs. This different level of detail is intentional. Greater detail is provided for those functions, structures, systems, and components that play key roles with regard to protecting radiological health and safety and that are not common to existing nuclear facilities already licensed by NRC. A number of radiological subjects are not addressed in the VA, (e.g., environmental qualification of equipment). Environmental qualification of equipment and other radiological safety considerations will be addressed in the LA. Non-radiological safety considerations such as silica dust control and other occupational safety considerations are considered equally important but are not addressed in

  3. Southern Nevada residents` views about the Yucca Mountain high-level nuclear waste repository and related issues: A comparative analysis of urban and rural survey data

    SciTech Connect

    Krannich, R.S.; Little, R.L.; Mushkatel, A.; Pijawka, K.D.; Jones, P.

    1991-10-01

    two separate surveys were undertaken in 1988 to ascertain southern Nevadans` views about the Yucca Mountain repository and related issues. The first of these studies focused on the attitudes and perceptions of residents in the Las Vegas metropolitan area. The second study addressed similar issues, but focused on the views of residents in six rural communities in three counties adjacent to the Yucca Mountain site. However, parallel findings from the two data sets have not been jointly analyzed in order to identify ways in which the views and orientations of residents in the rural and urban study areas may be similar or different. The purpose of this report is to develop and present a comparative assessment of selected issues addressed in the rural and urban surveys. Because both urban and rural populations would potentially be impacted by the Yucca Mountain repository, such an analysis will provide important insights into possible repository impacts on the well-being of residents throughout southern Nevada.

  4. Experimental determination of the solubility constant for magnesium chloride hydroxide hydrate (Mg 3Cl(OH) 5·4H 2O, phase 5) at room temperature, and its importance to nuclear waste isolation in geological repositories in salt formations

    NASA Astrophysics Data System (ADS)

    Xiong, Yongliang; Deng, Haoran; Nemer, Martin; Johnsen, Shelly

    2010-08-01

    In this study, the solubility constant of magnesium chloride hydroxide hydrate, Mg 3Cl(OH) 5·4H 2O, termed as phase 5, is determined from a series of solubility experiments in MgCl 2-NaCl solutions. The solubility constant in logarithmic units at 25 °C for the following reaction, MgCl(OH)·4HO+5H=3Mg+9HO(l)+Cl is calculated as 43.21 ± 0.33 (2 σ) based on the specific interaction theory (SIT) model for extrapolation to infinite dilution. The Gibbs free energy and enthalpy of formation for phase 5 at 25 °C are derived as -3384 ± 2 (2 σ) kJ mol -1 and -3896 ± 6 (2 σ) kJ mol -1, respectively. MgO (bulk, pure MgO corresponding to the mineral periclase) is the only engineered barrier certified by the Environmental Protection Agency (EPA) for emplacement in the Waste Isolation Pilot Plant (WIPP) in the US, and an Mg(OH) 2-based engineered barrier (bulk, pure Mg(OH) 2 corresponding to brucite) is to be employed in the Asse repository in Germany. Phase 5, and its similar phase, phase 3 (Mg 2Cl(OH) 3·4H 2O), could have a significant role in influencing the geochemical conditions in geological repositories for nuclear waste in salt formations where MgO or brucite is employed as engineered barriers. Based on our solubility constant for phase 5 in combination with the literature value for phase 3, we predict that the composition for the invariant point of phase 5 and phase 3 would be mMg = 1.70 and pmH = 8.94 in the Mg-Cl binary system. The recent WIPP Compliance Recertification Application Performance Assessment Baseline Calculations indicate that phase 5, instead of phase 3, is indeed a stable phase when the WIPP Generic Weep Brine (GWB), a Na-Mg-Cl-dominated brine associated with the Salado Formation, equilibrates with actinide-source-term phases, brucite, magnesium carbonates, halite and anhydrite. Therefore, phase 5 is important to the WIPP, and potentially important to other repositories in salt formations.

  5. Progress in evaluation of radionuclide geochemical information developed by DOE high-level nuclear waste repository site projects: Report for April 1986--September 1987

    SciTech Connect

    Meyer, R.E.; Arnold, W.D.; Blencoe, J.G.; O`Kelley, G.D.; Land, J.F.

    1988-07-01

    During this report period, all experiments were conducted with tuff from the proposed high-level nuclear waste site at Yucca Mountain, Nevada. Batch sorption ratio determinations were conducted for strontium, cesium, uranium, and technetium onto samples of tuff using real and synthetic groundwater J-13. There were no significant differences in sorption ratios in experiments with real and synthetic groundwater. Columns were tested by determination of elution curves in J-13 containing tritium and technetium as the TcO{sub 4}/sup {minus}/ ion. For strontium and cesium, fairly good correlation between values of the sorption ratio obtained by the two methods was observed. Little technetium sorption was observed with either method. The elution peaks obtained with neptunium and uranium were asymmetrical and the shapes were often complex, observations which suggest irreversibilities in the sorption reaction. Synthetic groundwater J-13 was slowly dripped onto a slab of tuff maintained at 95--100{degree}C, and the result was a thin encrustation of solids on the slab as the water evaporated. Fresh J-13 groundwater was then allowed to contact the encrustation in a vessel maintained at 90{degree}C. The principal result of the experiment was a significant loss of calcium and magnesium from the fresh J-13 groundwater. 13 refs. 25 figs., 9 tabs.

  6. Nuclear waste policy and politics

    SciTech Connect

    Carter, L.J.

    1989-12-31

    The nation`s nuclear waste problem began in 1955 but did not draw widespread public attention until the early 1970s. It was then that the old Atomic Energy commission got in trouble by prematurely designating a site in Lyons, Kansas, as its first nuclear waste repository. This and several other false starts, coupled with the growing environmental and anti-nuclear movements, thrust the issue to the forefront of national consciousness. in the meantime, growing quantities of waste were accumulating at nuclear power plants across the country, creating mounting pressure for action. Congress acted in 1982 and again in 1987. Its 1987 decision was decisive: stop the nationwide search for a disposal site, and focus all efforts on Yucca Mountain in Nevada. Despite the clear Congressional mandate, the program is again bogged down in controversy, internal conflicts, and bureaucracy. Its future depends on a solution to these problems. And the solution involves charting some new and innovative paths around political and technical mine fields.

  7. Paleostress evolution through 1.7 Gyr of geological history - Brittle deformation of the Olkiluoto Island, SW Finland, and implications on the characterisation of a high-level nuclear waste repository

    NASA Astrophysics Data System (ADS)

    Mattila, Jussi; Viola, Giulio; Zwingmann, Horst

    2013-04-01

    Olkiluoto Island, located in SW Finland, is being evaluated as the potential final repository for the high-level nuclear waste generated in Finland, and the repository is expected to become operational in A.D. 2020. The bedrock at Olkiluoto is formed by the crystalline basement of the Fennoscandian Shield and consists of Proterozoic amphibolite-facies metasedimentary rocks and gneisses. During feasibility studies for deep geological repositories for high-level nuclear waste, it is essential to characterise in detail potential fluid flow pathways and structures prone to movements during the repository life span. In crystalline geological settings these consist mainly of existing brittle structures. As a part of these studies at Olkiluoto Island, we documented in detail the character and kinematics of the fault zones of the site and developed a conceptual model of the brittle deformational history of the region by using a unique fault-slip data set consisting of more than 2000 striated faults, collected from both drill cores and the walls of an investigation tunnel reaching to the depth of 420 meters. By applying iterative inversion procedures on the fault-slip data, combined with the investigation of the regional brittle structures through the analysis of key outcrops, it was possible to generate distinct paleostress tensors and to define specific tectonic events at the site. The results were strengthened by comparing the output with the known paleostress states of southern Scandinavia and by using absolute and relative time criteria. Uniaxial compression of presumably late Svecofennian age with a regional NNW- SSE ?1 axis was active soon after 1.75 Ga ago, when brittle deformation was first accommodated in the region. A younger transpressive paleostress field with a NE-SW ?1 axis caused reactivation of some of the structures formed during the first shortening event. A phase of ESE-WNW extension is constrained by a number of tensors and direct field evidence and is

  8. A TRANSPORTATION RISK ASSESSMENT TOOL FOR ANALYZING THE TRANSPORT OF SPENT NUCLEAR FUEL AND HIGH-LEVEL RADIOACTIVE WASTE TO THE PROPOSED YUCCA MOUNTAIN REPOSITORY

    SciTech Connect

    NA

    2001-02-15

    The Yucca Mountain Draft Environmental Impact Statement (DEIS) analysis addressed the potential for transporting spent nuclear fuel and high-level radioactive waste from 77 origins for 34 types of spent fuel and high-level radioactive waste, 49,914 legal weight truck shipments, and 10,911 rail shipments. The analysis evaluated transportation over 59,250 unique shipment links for travel outside Nevada (shipment segments in urban, suburban or rural zones by state), and 22,611 links in Nevada. In addition, the analysis modeled the behavior of 41 isotopes, 1091 source terms, and used 8850 food transfer factors (distinct factors by isotope for each state). The analysis also used mode-specific accident rates for legal weight truck, rail, and heavy haul truck by state, and barge by waterway. This complex mix of data and information required an innovative approach to assess the transportation impacts. The approach employed a Microsoft{reg_sign} Access database tool that incorporated data from many sources, including unit risk factors calculated using the RADTRAN IV transportation risk assessment computer program. Using Microsoft{reg_sign} Access, the analysts organized data (such as state-specific accident and fatality rates) into tables and developed queries to obtain the overall transportation impacts. Queries are instructions to the database describing how to use data contained in the database tables. While a query might be applied to thousands of table entries, there is only one sequence of queries that is used to calculate a particular transportation impact. For example, the incident-free dose to off-link populations in a state is calculated by a query that uses route segment lengths for each route in a state that could be used by shipments, populations for each segment, number of shipments on each segment, and an incident-free unit risk factor calculated using RADTRAN IV. In addition to providing a method for using large volumes of data in the calculations, the

  9. Enlargement of the Baldone near-surface radioactive waste repository

    SciTech Connect

    Dreimanis, A.

    2007-07-01

    A unified analysis of the enlargement of the Baldone near-surface radioactive waste (RW) repository RADONS considers the interplay of the existing engineering, safety and infrastructure premises, with the foreseen newly socio-technical features. This enlargement consists in construction of two additional RW disposal vaults and in building a long-term storage facility for spent sealed sources at the RADONS territory. Our approach is based on consecutive analysis of following basic elements: - the origin of enlargement - the RADONS safety analysis and a set of optimal socio-technical solutions of Salaspils research reactor decommissioning waste management; - the enlargement - a keystone of the national RW management concept, including the long-term approach; - the enlargement concept - the result of international co-operation and obligations; - arrangement optimization of new disposal and storage space; - environmental impact assessment for the repository enlargement - the update of socio-technical studies. The study of the public opinion revealed: negative attitude to repository enlargement is caused mainly due to missing information on radiation level and on the RADONS previous operations. These results indicate: basic measures to improve the public attitude to repository enlargement: the safety upgrade, public education and compensation mechanisms. A detailed stakeholders engagement and public education plan is elaborated. (author)

  10. Insights to repository performance through study of a nuclear test site

    SciTech Connect

    Smith, D K; Kersting, A B; Thompson, J L; Finnegan, D L

    2000-07-12

    Underground nuclear test sites offer an unprecedented opportunity to evaluate processes relevant to high-level waste repository performance in the absence of engineered barriers. Radionuclide migration programs at the Nevada Test Site represent a twenty-five year systematic investigation of the diverse radiologic source terms residual from weapons testing and the evolution of the hydrologic source term which comprises those radionuclides dissolved in or otherwise available for transport by groundwater. The Nevada Test Site shares actinide source terms, correlative geology, an identical tectonic setting, similar climate, and a thick unsaturated zone with the adjacent proposed Yucca Mountain high-level waste repository and provides a natural laboratory to assess long-term radionuclide transport in the near field. Analog studies may ultimately help validate predictions of radionuclide transport from the Yucca Mountain repository.