A system for predicting the consequences of atmospheric releases from nuclear facilities located in complex terrain

A system is presented for the prediction of the consequences of an accidental atmospheric release from a nuclear power plants. In this system, concentration calculations are performed with a three-dimensional Gaussian plume trajectory model. The potential flow model or quasi-potential flow model developed in our laboratory is used to provide the three-dimensional space- and time-varying advection field to the trajectory diffusion model. The meteorological data required by those wind field models are observed or forecasted winds at a certain point typical of inflow boundary condition. The forecasted winds are calculated from a statistical model using principal component analysis and maximum entropy method. The diffusion parameters are estimated from the concentration distributions measured with wind tunnel experiments for the topographical models of a site of interest and its surroundings. The gamma exposure rates due to radioactive plumes are calculated from a simplified exposure model based on plume segment model. The dose assessment method described in this report is useful in real-time estimation of the behavior of radioactive plumes released from nuclear facilities located in complex terrain. (author)