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Automated emergency meteorological response system

Description: A sophisticated emergency response system was developed to aid in the evaluation of accidental releases of hazardous materials from the Savannah River Plant to the environment. A minicomputer system collects and archives data from both onsite meteorological towers and the National Weather Service. In the event of an accidental release, the computer rapidly calculates the trajectory and dispersion of pollutants in the atmosphere. Computer codes have been developed which provide a graphic display of predicted concentration profiles downwind from the source, as functions of time and distance.
Date: January 1, 1980
Creator: Pepper, D W
Partner: UNT Libraries Government Documents Department

Calculation of particulate dispersion in a design-basis tornadic storm from the Atomics International Nuclear Material Development Facility, Santa Susana, California

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at the Atomics International Nuclear Material Development Facility at Santa Susana, California. Plutonium particles less than 20 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind values are based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The method of moments is used to incorporate subgrid-scale resolution of the concentration within a grid cell volume. This method is a quasi-Lagrangian scheme which minimizes numerical error associated with advection. In all case studies, the effects of updrafts and downdrafts, coupled with scavenging of the particulates by precipitation, account for most of the material being deposited within 50 km downwind of the plant site. Ground-level isopleths in the x-y plane show that most of the material is deposited behind and slightly to the left of the centerline trajectory of the storm. Approximately 5% of the material is dispersed into the stratosphere and anvil section of the storm.
Date: July 1, 1980
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Calculation of particulate dispersion in a design-basis tornadic storm from the Battelle Memorial Institute, Columbus, Ohio

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at the Battelle Memorial Institute at Columbus, Ohio. Plutonium particles less than 20 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind value is based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The method of moments is used to incorporate subgrid-scale resolution of the concentration within a grid cell volume.
Date: October 1, 1980
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Calculation of particulate dispersion in a design-basis tornadic storm from the Babcock and Wilcox Plant, Leechburg, Pennsylvania

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at the Babcock and Wilcox Plutonium Fabrication Facility at Leechburg, Pennsylvania. Plutonium particles lss than 20 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind values are based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The quasi-Lagrangian method of moments is used to model the transport of concentration within a grid cell volume.
Date: March 1, 1978
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Calculation of particulate dispersion in a design-basis tornadic storm from the General Electric Vallecitos Nuclear Center, Vallecitos, California

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at the General Electric Vallecitos Nuclear Center at Vallecitos, California. Plutonium particles less than 20 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind values are based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The method of moments is used to incorporate subgrid-scale resolution of the concentration within a grid cell volume. This method is a quasi-Lagrangian scheme which minimizes numerical error associated with advection. In all case studies, the effects of updrafts and downdrafts, coupled with scavenging of the particulates by precipitation, account for most of the material being deposited within 20 to 45 km downwind of the plant site. Ground-level isopleths in the x-y plane show that most of the material is deposited behind and slightly to the left of the centerline trajectory of the storm. Approximately 5% of the material is dispersed into the stratosphere and anvil section of the storm.
Date: November 1, 1979
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Calculation of particulate dispersion in a design-basis tornadic storm from the Exxon Nuclear Company, Richland, Washington

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at the Exxon Nuclear Company at Richland, Washington. Plutonium particles less than 20 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind values are based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The method of moments is used to incorporate subgrid-scale resolution of the concentration within a grid cell volume. This method is a quasi-Lagrangian scheme which minimizes numerical error associated with advection. In all case studies, the effects of updrafts and downdrafts, coupled with scavenging of the particulates by precipitation, account for most of the material being deposited within 20 to 45 km downwind of the plant site. Ground-level isopleths in the x-y plane show that most of the material is deposited behind and slightly to the left of the centerline trajectory of the storm. Approximately 5% of the material is dispersed into the stratosphere and anvil section of the storm.
Date: July 1, 1978
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Dispersion of radioactive pollutant in a tornadic storm

Description: A three-dimensional numerical model is used to calculate ground-level air concentration and deposition (due to precipitation scavenging) after a hypothetical tornado strike at a plutonium fabrication facility in Pennsylvania. Plutonium particles less than 10 ..mu..m in diameter are assumed to be lifted into the tornadic storm cell by the vortex. The rotational characteristics of the tornadic storm are embedded within the larger mesoscale flow of the storm system. The design-basis translational wind values are based on probabilities associated with existing records of tornado strikes in the vicinity of the plant site. Turbulence exchange coefficients are based on empirical values deduced from experimental data in severe storms and from theoretical assumptions obtained from the literature. The quasi-Lagrangian method of moments is used to model the transport of concentration within a grid cell volume. In all case studies, the effects of updrafts and downdrafts, coupled with scavenging of the particulates by precipitation, account for most of the material being deposited within 20 to 45 km downwind of the plant site. Ground-level isopleths in the x-y plane show that most of the material is deposited behind and slightly to the left of the centerline trajectory of the storm. Approximately 5% of the material is dispersed into the stratosphere and anvil section of the storm.
Date: May 1, 1981
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Numerical Solution of Natural Convection in Eccentric Annuli

Description: The governing equations for transient natural convection in eccentric annular space are solved with two high-order accurate numerical algorithms. The equation set is transformed into bipolar coordinates and split into two one-dimensional equations: finite elements are used in the direction normal to the cylinder surfaces; the pseudospectral technique is used in the azimuthal direction. This report discusses those equations.
Date: September 18, 2001
Creator: Pepper, D.W.
Partner: UNT Libraries Government Documents Department

Tornado activity at SRP during 1976

Description: Tracks of three small tornadoes were confirmed on the site of the Savannah River Plant during 1976. Only minor damage to buildings and vehicles was experienced. The tornadoes were rated F1 on the Fujita-Pearson scale. Synoptic weather conditions from the National Weather Service and from the SRP seven-tower data system were recorded.
Date: July 1, 1978
Creator: Pepper, D.W. & Schubert, J.F.
Partner: UNT Libraries Government Documents Department

Numerical solution of three-dimensional natural convection by the strongly implicit procedure

Description: A numerical model has been developed to solve three-dimensional laminar flow in enclosures. The model is based on a three-dimensional strongly implicit procedure (SIP). In simple cases of natural convection due to differential side heating, numerical results at low and moderate Rayleigh numbers agree with results appearing in the literature. Although the model requires a moderate amount of computer storage, computation times are relatively fast. The simple case of heating a cubical room by a uniform floor or ceiling heat system with a vertical wall exposed to a uniformly cooled surface is also investigated.
Date: unknown
Creator: Pepper, D.W. & Harris, S.D.
Partner: UNT Libraries Government Documents Department

Numerical solutions for a general set of problems by an alternating strongly implicit procedure

Description: A generalized numerical method is developed for analyzing the following problems: driven laminar flow past a square cavity, laminar flow past a cylinder located in an infinite fluid, transient analysis of the preceding problem, and heat transfer in driven laminar flow past a cavity.
Date: January 1, 1978
Creator: Pepper, D.W. & Cooper, R.E.
Partner: UNT Libraries Government Documents Department

Modeling pollutant dispersion over irregular terrain with second moments and cubic splines

Description: Under ideal conditions, dispersion can be reasonably predicted with analytical methods, such as Gaussian puff/plume theory. However, analytical methods are typically inflexible under variable wind conditions, particularly in cases where dispersion occurs over irregular surfaces. A specific need exists for more detailed study into the effect of surface irregularities on dispersion. The requirement is to establish an accurate and efficient numerical solution algorithm for three-dimensional mesoscale atmospheric transport and diffusion over irregular terrain. Herein, a three-dimensional method-of-moments technique is employed to calculate pollutant advection. The method is based on the calculation of moment distributions of a concentration within a cell (volume). By summing moments over the solution domain, and using a Lagrangian advection scheme, concentration can be transported without generation of numerical dispersion error. Because the method maintains subgrid scale resolution, problems involving steep gradients can be calculated without significant computational damping. Three-dimensional diffusion is solved by the method of cubic splines. The cubic spline method is based on continuous-curvature cubic spline relations used as interpolation functions for first and second derivative terms. After solution of the diffusion terms, the first and second moments are recalculated to ensure continuity with the advection terms. To reduce computer programming complexity, the procedure of fractional steps is used to calculate the three-dimensional solutions. A coordinate transformation is employed to transform the terrain-lid variability into regular intervals in the computational domain. Simple tests are conducted to determine the accuracy of the numerical methods. The effect of topography on a continuous emission is examined under ideal conditions and the results compared with values obtained from an analytical Gaussian plume relation.
Date: January 1, 1978
Creator: Pepper, D.W. & Baker, A.J.
Partner: UNT Libraries Government Documents Department

Modeling the dispersion of atmospheric pollution using cubic splines and Chapeau functions. [Environmental transport of chemical and radioactive gaseous wastes at Savannah River Plant]

Description: A quasi-Lagrangian cubic-spline method and a chapeau-function (Galerkin) method are investigated and numerical results compared in advecting a passive scalar. Both methods are simple to use, computationally fast, and give reasonably accurate results. Little numerical dissipation is manifested by either scheme. In simple advection tests with equal mesh spacing, chapeau functions are more accurate than the quasi-Lagrangian cubic-spline method for maintaining peak concentration values. In tests with unequal mesh spacing, cubic-spline methods have lower reflectivity (noise) than chapeau functions and maintain slightly more accurate concentration distributions. Both cubic splines and chapeau functions are used to solve the dispersion of gaseous emissions in three dimensions over the Savannah River Plant (SRP). Real-time winds are obtained from measured data and interpolated to nodal points. Vertical diffusion is calculated from similarity theory and an O'Brien cubic profile. Results obtained from chapeau functions are compared to measured data after the 1974 accidental tritium release from SRP.
Date: January 1, 1977
Creator: Pepper, D.W. & Kern, C.D.
Partner: UNT Libraries Government Documents Department

Investigation of multi-dimensional computational models for calculating pollutant transport

Description: A performance study of five numerical solution algorithms for multi-dimensional advection-diffusion prediction on mesoscale grids was made. Test problems include transport of point and distributed sources, and a simulation of a continuous source. In all cases, analytical solutions are available to assess relative accuracy. The particle-in-cell and second-moment algorithms, both of which employ sub-grid resolution coupled with Lagrangian advection, exhibit superior accuracy in modeling a point source release. For modeling of a distributed source, algorithms based upon the pseudospectral and finite element interpolation concepts, exhibit improved accuracy on practical discretizations.
Date: January 1, 1980
Creator: Pepper, D W; Cooper, R E & Baker, A J
Partner: UNT Libraries Government Documents Department

Simulation of natural convection in a rectangular loop using finite elements

Description: A two-dimensional finite-element analysis of natural convection in a rectangular loop is presented. A psi-omega formulation of the Boussinesque approximation to the Navier-Stokes equation is solved by the false transient technique. Streamlines and isotherms at Ra = 10/sup 4/ are shown for three different modes of heating. The results indicate that corner effects should be considered when modeling flow patterns in thermosyphons.
Date: January 1, 1984
Creator: Pepper, D W; Hamm, L L & Kehoe, A B
Partner: UNT Libraries Government Documents Department

Modeling pollutant transport using a meshless-lagrangian particle model

Description: A combined meshless-Lagrangian particle transport model is used to predict pollutant transport over irregular terrain. The numerical model for initializing the velocity field is based on a meshless approach utilizing multiquadrics established by Kansa. The Lagrangian particle transport technique uses a random walk procedure to depict the advection and dispersion of pollutants over any type of surface, including street and city canyons
Date: January 1, 2002
Creator: Carrington, D. B. (David B.) & Pepper, D. W. (Darrell W.)
Partner: UNT Libraries Government Documents Department