Geologic and geohydrologic data for the Paradox Basin have been used to simulate movement of ground water and radioactive contaminants from a hypothetical nuclear reactor spent fuel repository after an assumed accidental release. The pathlines, travel times and velocity of the ground water from the repository to the discharge locale (river) were determined after the disruptive event by use of a two-dimensional finite difference hydrologic model. The concentration of radioactive contaminants in the ground water was calculated along a series of flow tubes by use of a one-dimensional mass transport model which takes into account convection, dispersion, contaminant/ media interactions and radioactive decay. For the hypothetical site location and specific parameters used in this demonstration, it is found that Iodine-129 (1-129) is the only isotope reaching the Colorado River in significant concentration. The 1-129 is transported to the river at a maximum concentration of about 1.84 x 10-8 microcuries per milliliter (~Ci/ml). This concentration occurs about 8.0 x 10 5 years after the repository has been breached. This 1-129 groundwater concentration is about 0.3 of the drinking water standard for uncontrolled use. The groundwater concentration would then be diluted by the Colorado River (mean flow of 7,000 ft 3 /sec to about 2.13 x 10-13 ~Ci/ml. None of the actinide elements reach more than half the distance from the repository to the Colorado River in the two-million year model run time. As an example, Radium-226, at a maximum concentration, has travelled 0.46 of the distance to the river in two million years. Radium-226 concentration in the ground water at that point in space and time is 1.02 x 10-7 ~Ci/ml. This exercise demonstrates that the W1SAP model system is applicable for analysis of contaminant transport. The results presented in this report, however, are valid only for one particular set of parameters. A complete sensitivity analysis must be performed to evaluate the range of effects from the release of contaminants from a breached repository. iii. . SUMMARY LIST OF FIGURES.
PNL-3162 PATHS Groundwater Hydrologic Code-PATHS is a first-level (simplest), idealized, hybrid analytical/numerical code for two-dimensional, saturated groundwater flow and single component transport. The geology of the modeled region must be homogeneous. PNL-3160 VTT (Variable Thickness Transient) Groundwater Hydrologic Code-VTT is a second-level (intermediate complexity) twodimensional saturated groundwater flow code, using the Boussinesq approximation, finite difference approach. It has two-dimensional (quasi three-dimensional) multiaquifer capability. Heterogeneous geology is considered. PNL-2939 FE3DGW (Finite-Element, Three-Dimensional Groundwater) Hydrologic Code-FE3DGW is a third-level (high complexity) three-dimensional, finite-element approach (Galerkin formulation) to solve for saturated groundwater flow. Heterogeneous geology is considered .
Abstract. The authors introduce a method for extracting weather and climate data from a historical plantation document. They demonstrate the method on a document from Shirley Plantation in Virginia (USA) covering the period 1816–1842. They show how the resulting data are organized into a spreadsheet that includes direct weather observations and information on various cultivars. They then give three examples showing how the data can be used for climate studies. The first example is a comparison of spring onset between the plantation era and the modern era. A modern median final spring freeze event (for the years 1943–2017) occurs a week earlier than the historical median (for the years 1822–1839). The second analysis involves developing an index for midsummer temperatures from the timing of the first malaria-like symptoms in the plantation population each year. The median day when these symptoms would begin occurring in the modern period is a month and a half earlier than the median day they occurred in the historical period. The final example is a three-point temperature index generated from ordinal weather descriptions in the document. The authors suggest that this type of local weather information from historical archives, either direct from observations or indirect from phenophase timing, can be useful toward a more complete understanding of climates of the past.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.