Download or read book RADIONUCLIDE TRANSPORT MODELS UNDER AMBIENT CONDITIONS written by S. Magnuson and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this model report is to document the unsaturated zone (UZ) radionuclide transport model, which evaluates, by means of three-dimensional numerical models, the transport of radioactive solutes and colloids in the UZ, under ambient conditions, from the repository horizon to the water table at Yucca Mountain, Nevada.
Download or read book Radionuclide Transport Models Under Ambient Conditions written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this Analysis/Model Report (AMR) is to evaluate (by means of 2-D semianalytical and 3-D numerical models) the transport of radioactive solutes and colloids in the unsaturated zone (UZ) under ambient conditions from the potential repository horizon to the water table at Yucca Mountain (YM), Nevada. This is in accordance with the ''AMR Development Plan U0060, Radionuclide Transport Models Under Ambient Conditions'' (CRWMS M and O 1999a). This AMR supports the UZ Flow and Transport Process Model Report (PMR). This AMR documents the UZ Radionuclide Transport Model (RTM). This model considers: the transport of radionuclides through fractured tuffs; the effects of changes in the intensity and configuration of fracturing from hydrogeologic unit to unit; colloid transport; physical and retardation processes and the effects of perched water. In this AMR they document the capabilities of the UZ RTM, which can describe flow (saturated and/or unsaturated) and transport, and accounts for (a) advection, (b) molecular diffusion, (c) hydrodynamic dispersion (with full 3-D tensorial representation), (d) kinetic or equilibrium physical and/or chemical sorption (linear, Langmuir, Freundlich or combined), (e) first-order linear chemical reaction, (f) radioactive decay and tracking of daughters, (g) colloid filtration (equilibrium, kinetic or combined), and (h) colloid-assisted solute transport. Simulations of transport of radioactive solutes and colloids (incorporating the processes described above) from the repository horizon to the water table are performed to support model development and support studies for Performance Assessment (PA). The input files for these simulations include transport parameters obtained from other AMRs (i.e., CRWMS M and O 1999d, e, f, g, h; 2000a, b, c, d). When not available, the parameter values used are obtained from the literature. The results of the simulations are used to evaluate the transport of radioactive solutes and colloids, and to determine the processes, mechanisms, and geologic features that have a significant effect on it. They evaluate the contributions of daughter products of radioactive decay to transport from the bottom of the potential repository to the water table. The effect of the various conceptual models of perched water bodies on transport is also evaluated. Note that a more thorough study of perched water bodies can be found in another AMR (CRWMS M and O 1999d, Sections 6.2 and 6.6). The primary caveat for using the modeling results documented here is that the input transport parameters were based on limited site data. For some input parameters, best estimates were used because no specific data were available. An additional caveat is that the RTM is based on the conceptual models and numerical approaches used for developing the flow fields and infiltration maps, and thus they share the same limitations.
Download or read book Drift Scale Radionuclide Transport written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this model report is to document the drift scale radionuclide transport model, taking into account the effects of emplacement drifts on flow and transport in the vicinity of the drift, which are not captured in the mountain-scale unsaturated zone (UZ) flow and transport models ''UZ Flow Models and Submodels'' (BSC 2004 [DIRS 169861]), ''Radionuclide Transport Models Under Ambient Conditions'' (BSC 2004 [DIRS 164500]), and ''Particle Tracking Model and Abstraction of Transport Process'' (BSC 2004 [DIRS 170041]). The drift scale radionuclide transport model is intended to be used as an alternative model for comparison with the engineered barrier system (EBS) radionuclide transport model ''EBS Radionuclide Transport Abstraction'' (BSC 2004 [DIRS 169868]). For that purpose, two alternative models have been developed for drift-scale radionuclide transport. One of the alternative models is a dual continuum flow and transport model called the drift shadow model. The effects of variations in the flow field and fracture-matrix interaction in the vicinity of a waste emplacement drift are investigated through sensitivity studies using the drift shadow model (Houseworth et al. 2003 [DIRS 164394]). In this model, the flow is significantly perturbed (reduced) beneath the waste emplacement drifts. However, comparisons of transport in this perturbed flow field with transport in an unperturbed flow field show similar results if the transport is initiated in the rock matrix. This has led to a second alternative model, called the fracture-matrix partitioning model, that focuses on the partitioning of radionuclide transport between the fractures and matrix upon exiting the waste emplacement drift. The fracture-matrix partitioning model computes the partitioning, between fractures and matrix, of diffusive radionuclide transport from the invert (for drifts without seepage) into the rock water. The invert is the structure constructed in a drift to provide the floor of the drift. The reason for introducing the fracture-matrix partitioning model is to broaden the conceptual model for flow beneath waste emplacement drifts in a way that does not rely on the specific flow behavior predicted by a dual continuum model and to ensure that radionuclide transport is not underestimated. The fracture-matrix partitioning model provides an alternative method of computing the partitioning of radionuclide releases from drifts without seepage into rock fractures and rock matrix. Drifts without seepage are much more likely to have a significant fraction of radionuclide releases into the rock matrix, and therefore warrant additional attention in terms of the partitioning model used for TSPA.
Download or read book Behavior of Radionuclides in the Environment I written by Kenji Kato and published by Springer Nature. This book was released on 2020-02-18 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 3-volume set highlights the behavior of radionuclides in the environment and focusing on the development of related fields of study, including microbiology and nanoscience. In this context, it discusses the behavior of radionuclides released in areas of Lake Karachai in Ural, and those released as a result of Chernobyl accident (1986), and in Fukushima (2011). Volume I presents the experiences gained in South Urals (“Mayak” plant, Lake Karachai), providing a scientific basis for more precise understanding of the behavior of radionuclides in complex subsurface environments. On the basis of monitoring data, it examines the pathways of radionuclide migration and the influence of the geological environment and groundwater on the migration, with a particular focus on particles from the nanoscale to microscale. It also discusses the function of microbes and microscale particles, from their direct interaction with radionuclides to their ecological role in changing the physic-chemical condition of a given environment. Lastly, the protective properties of geological media are also characterized, and mathematical modeling of contaminant migration in the area of Lake Karachai is used to provide information regarding the migration of radionuclides.
Download or read book Site Characterization Progress Report written by and published by . This book was released on 2001 with total page 86 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Drift Scale Radionuclide Transport written by P. R. Dixon and published by . This book was released on 2004 with total page 189 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this Model Report is to document two models for drift-scale radionuclide transport. This has been developed in accordance with ''Technical Work Plan for: Performance Assessment Unsaturated Zone'' (Bechtel SAIC Company, LLC (BSC) 2002 [160819]), which includes planning documents for the technical work scope, content, and management of this Model Report in Section 1.15, Work Package AUZM11, ''Drift-Scale Radionuclide Transport.'' The technical work scope for this Model Report calls for development of a process-level model and an abstraction model representing diffusive release from the invert to the rocks, partitioned between fracture and matrix, as compared to the fracture-release approach used in the Site Recommendation. The invert is the structure constructed in a drift to provide the floor of that drift. The plan for validation of the models documented in this Model Report is given in Section I-5 of Attachment I in BSC (2002 [160819]). Note that the model validation presented in Section 7 deviates from the technical work plan (BSC 2002 [160819], Section I-5) in that an independent technical review specifically for model validation has not been conducted, nor publication in a peer-reviewed journal. Model validation presented in Section 7 is based on corroboration with alternative mathematical models, which is also called out by the technical work plan (BSC 2002 [160819], Section I-5), and is sufficient based on the requirements of AP-SIII. 10Q for model validation. See Section 7 for additional discussion. The phenomenon of flow and transport in the vicinity of the waste emplacement drift are evaluated in this model report under ambient thermal, chemical, and mechanical conditions. This includes the effects of water diversion around an emplacement drift and the flow and transport behavior expected in a fractured rock below the drift. The reason for a separate assessment of drift-scale transport is that the effects of waste emplacement drifts on flow are not captured in the flow fields used for radionuclide transport at the mountain scale (''UZ Flow Models and Submodels'', BSC 2003 [163045]).
Download or read book Description and Evaluation of the Atmospheric Radionuclide Transport Model ARTM written by Robert Hanfland and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In Germany, the Lagrangian Atmospheric Radionuclide Transport Model (ARTM) was developed in order to monitor and forcast the immission of discharges from nuclear facilities within a typical distance of up to 20 km and within the planetary boundary layer. Such transport models have to be validated carefully to make sure that they simulate tracer dispersions comparable to reality. This study shows the description and extension of ARTM as well as the analysis of the three-dimensional dispersion properties and their evaluation. In a sensitivity study, the effects of stability class, roughness length, zero-plane displacement, source height and tracer type on the three-dimensional plume dispersion are analysed. Furthermore, the dispersion of five different turbulence models are studied. Airborne CO2 observations in the vicinity of the lignite power plant Bełchatów, Poland, allow to evaluate the model performance under unstable boundary layer conditions. An intercomparison of ARTM with numerical weather prediction and large-eddy simulation models extend the investigation to slightly unstable atmospheric conditions. The results show that the stability class, as a parametrisation of the atmospheric stability, causes the largest impact to the simulation results. The turbulence models show deviation from the well-mixed state by up to approx. 20%. All simulated mixing ratios are in the same order of magnitude as the airborne in situ data. Although, some turbulence models underestimate the plume widths by up to 50%. The results of this work help to improve the agreement of plumes simulated by ARTM with real plumes under very unstable atmospheric conditions by the selection of distinct turbulence models.
Download or read book Numerical Modeling of a Thermohydrochemical T H C Coupling and the Implications to Radionuclide Transport written by and published by . This book was released on 1999 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thermohydrochemical (T-H-C) processes result from the placement of heat-generating radioactive materials in unsaturated, fractured geologic materials. The placement of materials in the proposed Yucca Mountain repository will result in complex environmental conditions. Simple models are developed liking the thermohydrological effects simulated with TOUGHZ to system chemistry, with an example presented for chloride. Perturbations to near-field chemistry could have a significant impact on the migration of actinides and fission products in geologic materials. Various conceptual models to represent fractures are utilized in TOUGHZ simulations of thermohydrological processes. The simulated moisture redistribution is then coupled to simple chemical models to demonstrate the potential magnitude of T-H-C processes. The concentration of chloride in solution (returning to the engineered barrier system) is demonstrated, in extreme cases, to exceed 100,000 mg/L. The implication is that the system (typically ambient chemical and hydrological conditions) in which radionuclide transport is typically simulated and measured may be significantly different from the perturbed system.
Download or read book Hydrology and Geochemistry of Yucca Mountain and Vicinity Southern Nevada and California written by John S. Stuckless and published by Geological Society of America. This book was released on 2012 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radiological Risk Assessment and Environmental Analysis written by John E. Till and published by Oxford University Press. This book was released on 2008-07-10 with total page 729 pages. Available in PDF, EPUB and Kindle. Book excerpt: Radiological Risk Assessment and Environmental Analysis comprehensively explains methods used for estimating risk to people exposed to radioactive materials released to the environment by nuclear facilities or in an emergency such as a nuclear terrorist event. This is the first book that merges the diverse disciplines necessary for estimating where radioactive materials go in the environment and the risk they present to people. It is not only essential to managers and scientists, but is also a teaching text. The chapters are arranged to guide the reader through the risk assessment process, beginning with the source term (where the radioactive material comes from) and ending with the conversion to risk. In addition to presenting mathematical models used in risk assessment, data is included so the reader can perform the calculations. Each chapter also provides examples and working problems. The book will be a critical component of the rebirth of nuclear energy now taking place, as well as an essential resource to prepare for and respond to a nuclear emergency.
Download or read book Modeling One dimensional Radionuclide Transport Under Time varying Fluid flow Conditions written by Fred Gelbard and published by . This book was released on 1989 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Use of Natural Analogues to Support Radionuclide Transport Models for Deep Geological Repositories for Long Lived Radioactive Wastes written by and published by . This book was released on 1999 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radionuclide Concentrations in Food and the Environment written by Michael Poschl and published by CRC Press. This book was released on 2006-08-21 with total page 473 pages. Available in PDF, EPUB and Kindle. Book excerpt: As radiological residue, both naturally occurring and technologically driven, works its way through the ecosystem, we see its negative effects on the human population. Radionuclide Concentrations in Food and the Environment addresses the key issues concerning the relationship between natural and manmade sources of environmental radioactivity
Download or read book Radionuclide Transport Modeling in Unsaturated Zone at Transient and Steady state Conditions with Emphasis on the Impacts on Dose Assessment written by Zuo Tan and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Handbook on Radiation Environment Volume 1 written by Dinesh Kumar Aswal and published by Springer Nature. This book was released on with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulating radionuclide fate and transport in the unsaturated zone evaluation and sensitivity analyses of select computer models written by Jin-Song Chen and published by DIANE Publishing. This book was released on 2002 with total page 186 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Office of Civilian Radioactive Waste Management OCRWM Annual Report to Congress Fiscal Year 2001 written by and published by DIANE Publishing. This book was released on with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt:
