Download or read book The Role of Dispersion in Radionuclide Transport Data and Modeling Requirements written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This document is the collaborative effort of the members of an ad hoc subcommittee of the Underground Test Area Project Technical Working Group. This subcommittee was to answer questions and concerns raised by the Nevada Division of Environmental Protection to the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office, regarding Pahute Mesa Corrective Action Units (CAUs) 101 and 102. The document attempts to synthesize the combined comments made by each member of this subcommittee into insights made in the role of dispersion in radionuclide transport data and modeling. Dispersion is one of many processes that control the concentration of radionuclides in groundwater beneath the Nevada Test Site where CAUs 101 and 102 are located. In order to understand the role of dispersion in radionuclide transport, there is a critical need for CAU- or site-specific data related to transport parameters which is currently lacking, particularly in the case of Western a nd Central Pahute Mesa. The purpose of this technical basis document is to: (1) define dispersion and its role in contaminant transport, (2) present a synopsis of field-scale dispersion measurements, (3) provide a literature review of theories to explain field-scale dispersion, (4) suggest approaches to account for dispersion in CAU-scale radionuclide modeling, and (5) to determine if additional dispersion measurements should be made at this time.
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 Modelling of Marine Dispersion and Transfer of Radionuclides Accidentally Released from Land Based Facilities written by International Atomic Energy Agency and published by International Atomic Energy Agency. This book was released on 2019-09-24 with total page 144 pages. Available in PDF, EPUB and Kindle. Book excerpt: This publication describes and summarizes the work of the MODARIA (modelling and data for radiological impact assessments) Programme Working Group 10. MODARIA was set up to continue the IAEA's activities in the field of testing, comparing and developing guidance on the application of models to assess radiation exposures to humans and radiological impacts on the environment. Different aspects of the MODARIA programme were addressed by ten working groups. The current publication presents the work undertaken by Working Group 10 on the modelling of marine dispersion and transfer of radionuclides accidentally released from land-based facilities. Two marine dispersion scenarios were studied. These scenarios simulated dispersion of radionuclides in the Baltic Sea following the Chernobyl accident, and dispersion in the Pacific Ocean following the Fukushima Daiichi nuclear power plant accident. The publication details some general conclusions and presents a comparison of model performance when applied to the above scenarios. The difficulties of developing operative modelling systems for supporting decision making in cases of emergencies in highly dynamic environments are highlighted.
Download or read book Introduction to the Numerical Modeling of Groundwater and Geothermal Systems written by Jochen Bundschuh and published by CRC Press. This book was released on 2010-07-05 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an introduction to the scientific fundamentals of groundwater and geothermal systems. In a simple and didactic manner the different water and energy problems existing in deformable porous rocks are explained as well as the corresponding theories and the mathematical and numerical tools that lead to modeling and solving them. This
Download or read book A Practical Guide to Understanding Managing and Reviewing Environmental Risk Assessment Reports written by Sally L. Benjamin and published by CRC Press. This book was released on 2001-02-21 with total page 515 pages. Available in PDF, EPUB and Kindle. Book excerpt: A Practical Guide to Understanding, Managing and Reviewing Environmental Risk Assessment Reports provides team leaders and team members with a strategy for developing the elements of risk assessment into a readable and beneficial report. The authors believe that successful management of the risk assessment team is a key factor is quality repor
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 Reliability of Radioactive Transfer Models written by G. Desmet and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 379 pages. Available in PDF, EPUB and Kindle. Book excerpt: Assessment of the radiological impact of planned or existing practices involving the (actual or potential) release of radionuclides to the environment are largely based on the use of modelling techniques which allow prediction of the relationship between environmental levels and releases and the associated radiation dose to man. Models are imperfect means of representing environmental transfer processes, and it is essential to know the reliability which can be associated with the predictions of these models for each and every assessment situation. Such information is necessary in order to establish confidence in model predictions and, in particular, to allow adequate safety margins to be set in the design of nuclear facilities. This knowledge is also a prerequisite to determine release limits or to decide whether further research is justified in order to improve predictive accuracy. Therefore a number of distinguished pilpers have been presented during this workshop which focused both on practical aspects of variability of observations of facts occuring in nature, but also on learned aspects of the science of statistics. It is not very clear, however, whether much insight in mechanisms is gained by such an approach. This insight is probably rather reached by a straightforward judgment of the quality of the primary data and by the willingness to think over carefully the experiments and measurernents before doing them. The book is composed such as to give the reader the chance to quietly study the presented papers in good order.
Download or read book Radioactivity Transport in Water written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies were undertaken to obtain a more accurate concept of the transport of radionuclides in aquatic systems. Various stages of this research were completed and published previously in progress reports, and are listed in the references. These reports describe the dispersion, uptake, release, and transport of /sup 89/Sr, /sup 137/Cs, /sup 103/Ru, /sup 58/Co and /sup 51/Cr. Transport data were obtained by conducting laboratory, model river, and field tests. Canal, river, and estuarine environmerts provided the necessary field information on hydrodynamic dispersion and on uptake and release of radionuclides by sediments. Model river data provided most of the useful uptake and release information involving special sediments, plants, and aquatic environments. Topics discussed include the factors affecting radionuclide transport, the use of model rivers to study cortinuous release of radionuclides, and the influence of various environmental factors on the accumulation and desorption of mercurials by a fresh water alga. Radioactive isotopes of mercury in the form of mercuric mercury and methyl mercury were used as tracers. (CH).
Download or read book NCRP Report written by National Council on Radiation Protection and Measurements and published by . This book was released on 1966 with total page 498 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Subsurface Solute Transport Models and Case Histories written by Vyacheslav G. Rumynin and published by Springer Science & Business Media. This book was released on 2012-01-14 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book addresses the development of the basic knowledge of the subsurface solute transfer with a particular emphasis on field data collection and analysis coupled with modeling (analytical and numerical) tool application. The relevant theoretical developments are concerned mainly with the formulation and solution of deterministic mass-transport equations for a wide range of engineering issues in groundwater quality assessment and forecasting. The book gives many computational examples and case studies drawn from the conducted field investigations. The analyzed problems are as follows: investigation and prediction of groundwater contamination by industrial contaminants and solutions (radionuclides, chloride and nitrate brine) with special focus on the effect of (a) aquifer heterogeneity, anisotropy, and dual porosity, (b) density contrast existing between industrial waste and groundwater, or in density-stratified artesian and coastal groundwater systems; (c) physicochemical interactions that play a major role in retarding (e.g. adsorption) or enhancing (e.g. interactions between dissolved species and mobile colloids) contaminant transport; prediction of the effects of pumping on groundwater quality at wellfields; groundwater dating using stable and radioactive isotopes for prediction and assessment of contamination potential; field and laboratory tests’ design and analysis, and monitoring data interpretation; partitioning of surface and subsurface flows using isotope techniques. One of the most essential topics addressed in the book is the migration and fate of radionuclides. Model development is motivated by field data analysis from a number of radioactively contaminated sites in the Russian Federation: near-surface radioactive waste disposal sites and deep-well radioactive waste injection sites. They play a unique role in the advancement of knowledge of the subsurface behavior and fate of many hazardous radionuclides and can be considered as field-scale laboratories. Thus, the book, along with theoretical findings, contains field information, which will facilitate the understanding of subsurface solute transport and the development of a methodology for practical applications to groundwater hydrology.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radioactive Waste Management written by and published by . This book was released on 1981 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Viability Assessment of a Repository at Yucca Mountain Total system performance assessment written by and published by . This book was released on 1998 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Deep Geological Disposal of Radioactive Waste written by W. R. Alexander and published by Elsevier. This book was released on 2011-07-29 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: Deep Geological Disposal of Radioactive Waste presents a critical review of designing, siting, constructing and demonstrating the safety and environmental impact of deep repositories for radioactive wastes. It is structured to provide a broad perspective of this multi-faceted, multi-disciplinary topic: providing enough detail for a non-specialist to understand the fundamental principles involved and with extensive references to sources of more detailed information. Emphasis is very much on “deep geological disposal – at least some tens of metres below land surface and, in many cases, many hundred of metres deep. Additionally, only radioactive wastes are considered directly – even though such wastes often contain also significant chemotoxic or otherwise hazardous components. Many of the principles involved are generally applicable to other repository options (e.g. near-surface or on-surface disposal) and, indeed, to other types of hazardous waste. Presents a current critical review in designing, siting, constructing and demonsrating the safety and environmental impact of deep repositories for radwaste Addresses the fundamental principles of radioactive waste with up-to-date examples and real-world case studies Written for a multi-disciplinary audience, with an appropriate level of detail to allow a non-specialist to understand
Download or read book NUREG CR written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1980 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Radioactivity in the Environment written by E.M. Scott and published by Elsevier. This book was released on 2003-05-22 with total page 439 pages. Available in PDF, EPUB and Kindle. Book excerpt: Just as an environmental model typically will be composed of a number of linked sub-models, representing physical, chemical or biological processes understood to varying degrees, this volume includes a series of linked chapters exemplifying the fundamental nature of environmental radioactivity models in all compartments of the environment. Why is a book on modelling environmental radioactivity necessary? There are many reasons why such a boook is necessary, perhaps the most important that: - modelling is an often misunderstood and maligned activity and this book can provide, to a broad audience, a greater understanding of modelling power but also some of the limitations. - modellers and experimentalists often do not understand and mistrust each other's work yet they are mutually dependent, in the sense that good experimental science can direct good modelling work and vice-versa; we hope that this book can dispel mistrust and engender improved understanding. - there is an increasing reliance on model results in environmental management, yet there is also often misuse and misrepresentation of these results. This book can help to bridge the gap between unrealistic expectations of model power and the realisation of what is possible, practicable and feasible in modelling of environmental radioactivity; and finally, - modelling tools, capacity and power have increased many-fold in a relatively short period of time. Much of this is due to the much-heralded computer revolution, but much is also due to better science. It is useful to consider what gap if any still remains between what is possible and what is necessary.
Download or read book Site Characterization Progress Report written by and published by . This book was released on 1997 with total page 862 pages. Available in PDF, EPUB and Kindle. Book excerpt:
