Rancho Seco building wake effects on atmospheric diffusion: simulation in a meteorological wind tunnel

Meroney, Robert N., author
Peterka, Jon A., author
Allwine, K. J., author
Fluid Dynamics and Diffusion Laboratory, Department of Civil Engineering, Colorado State University, publisher
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Colorado State University. Libraries
Wind tunnel diffusion tests were conducted on 1:500 scale models of the Rancho Seco Nuclear Power Station, California; surrounding buildings, hyperbolic cooling towers, and terrain were similarly modeled in the Meteorological Wind Tunnel at Colorado State University. The purpose was to quantify the effects on diffusion of buildings perturbing the mean flow. The test program consisted of three gaseous tracer releases of gases having no appreciable plume rise from ground, building, and containment vessel top heights. The program was repeated for eight wind directions and cases of unstable, neutral, and stable atmospheric stratification conditions. Results show that the buildings significantly perturb the dispersion patterns from the flat terrain isolated source release case, hence buildings, hyperbolic towers, and terrain in the immediate vicinity of the release have a major effect. Maximum ground level normalized concentrations occurred during stable stratification. Upwind or downwind presence of the hyperbolic cooling towers was felt by the shift of ground level concentration values toward conditions approximately two categories more unstable than that suggested by the Pasquill-Gifford curves for the background flow stability. Data from three of the eight wind directions have been examined in some detail. These included 135°, containment building upwind of cooling towers; 225°, cooling towers to the side of the containment vessel wake; and 315°, cooling towers upwind of the containment vessel. If it is assumed that wind tunnel measurements are equivalent to field averaging times of 10 minutes, then the model concentrations adjusted to equivalent one-hour field sampling times overpredict field measurements for these cases by at most a factor of 1.7.
Prepared for Site Safety Research Branch, Office of Nuclear Regulatory Research, US. Nuclear Regulatory Commission.
Includes bibliographical references (pages 29-30).
March 1978. Revised December 1979.