Water Resources Research Program. Thermal Plumes from Submerged Discharges at Zion Nuclear Power Station: Additional Prototype Measurements of Interacting Plumes

摘要

Measurements were made of the thermal plumes from the two submerged discharges of the Zion plant into Lake Michigan during the summer of 1976. The survey results are reported in the form of horizontal isotherm maps at vertical intervals of 1.0 m, from the surface to a depth of 3.0 m, and of selected vertical cross sections. Ambient lake-water temperatures and currents were monitored throughout the study period. Analysis of data from two mappings of double plumes made in 1975 by Argonne at this site had indicated that significant interaction between the plumes from the adjacent discharges occurred in the presence of an ambient current. The interaction resulted in surface areas of the double plumes that were more than ten times the sum of two separate, single-discharge plumes. Comparisons of the results of the present surveys with the previous mappings are limited somewhat because of the difficulties in defining the ambient, or background, water temperature. Temperature data collected in the 1976 surveys exhibited large spatial and temporal variability. Vertical temperature stratification during one of these surveys resulted in entrainment of cooler near-bottom water, greatly reducing plume surface temperatures; and intrusion of a cool-water mass into the site area during the other survey made it possible to define only a range of ambient temperatures. The conclusions from the analysis of the additional double-plume data, constrained by the variability cited above, are that the surface isotherm areas associated with the downcurrent, shielded plume were larger than those of a single plume discharged in the same direction, and that the total double-plume surface isotherm area in one survey appears to exceed that of the sum of two separate, single-discharge plumes. (ERA citation 03:045360)