N Reactor thermal plume characterization study during dual-purpose mode of operation. Part I: Field investigation, Part II: Computer simulation

摘要

The U.S. Department of Energy was issued a National Pollutant Discharge Elimination System (NPDES) permit for operation of the N Reactor discharge from December 7, 1981, through December 31, 1985. Part 1.A.9 (Effluent Limitations, Monitoring Requirements, and Schedule of Compliance) states in part that a detailed low-flow receiving-water study be conducted to document the extent and nature of the existing outfall discharge plume. Pacific Northwest Laboratory conducted a two-phase program to characterize the N Reactor thermal plume. The work was performed for UNC Nuclear Industries, Inc., the operator of N Reactor for the U.S. Department of Energy (DOE). Part I of this report deals with the field studies to characterize the N Reactor thermal plume, performed September 15 through 20, 1982. It includes a description of the study area, a description of field tasks and procedures, and data collection results and discussion. The field studies consisted of a bathymetric survey, underway thermal surveys, dye dispersion surveys, and vertical velocity measurements. Part II is the computer simulation of the thermal plume under different flow conditions and the calibration of the model used. It includes a description of the computer model and the assumptions on which it is based, a presentation of the input data used in this application, and a discussion of modeling results. The model is used to predict the effects of the discharged heated water on downstream river temperatures for flow conditions from 36,000 cubic feet per second (cfs) to 300,000 cfs. Figures called out in the text of this report are found at the end of each section.