Browsing by Author "Nguyen, Chau"

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    Mixing and Heat Transfer of Cooling Water Discharges from the Monticello Nuclear Power Generating Plant into the Mississippi River
    (St. Anthony Falls Hydraulic Laboratory, 1976-03) Stefan, Heinz; Lake, Gary; Nguyen, Chau
    Water temperature data obtained in the Mississippi River downstream from the Monticello Nuclear Power Generating Plant during 32 field surveys have been analyzed and reduced to a form which permits the prediction of certain thermal plume characteristics using readily available plant operational, hydrologic and meteorological input data. To achieve this goal, dimensionless parameters are derived by analysis and applied in order to reduce the field data to simple graphical form and in some cases to semi-empirical equations. All results indicate that lateral turbulent mixing is the main mechanism by which cooling water effluents from the Monticello plant are diluted over the first three miles downstream from the outlet. There is no significant horizontal stratification and not much heat transfer to the atmosphere within the river reach studied.
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    Waste Heat Dissipation and Effluent Water Temperatures from Black Dog Lake
    (St. Anthony Falls Hydraulic Laboratory, 1976-07) Stefan, Heinz; Nguyen, Chau
    Northern States Power Company's Black Dog Power Generating Plant discharges its condenser cooling water into a pond called Black Dog Lake, which releases it through two outlets into the Minnesota River. In this study it was found that an average 63 percent of the heat load rejected by the plant was dissipated to the atmosphere by the lake during a period from March 1974 through January 1975. Daily heat dissipation varied from 15 to 128 percent because of temporary heat storage in the lake (lag) under transient weather conditions. Daily lake effluent temperature fluctuations were determined and compared to Minnesota River temperature fluctuations. The lake very effectively reduces the impact of thermal discharges on the Minnesota River. Its effectiveness was found to vary with season, with a maximum in midsummer and a minimum in midwinter, presumably due to sinking plumes. A mathematical model of the unsteady well-mixed type predicts summer effluent water temperatures well, but is not applicable for winter conditions.