Explosive Release Atmoshperic Dispersion (ERAD)

The Explosive Release Atmospheric Dispersion (ERAD) model is a three-dimensional numerical simulation of turbulent atmospheric transport and diffusion. This code is used to model the explosive release of radiological material from a single-point detonation or radiological dispersion device (RDD). ERAD uses an integral technique to describe the buoyant cloud's rise and downwind path as it rises into a single meteorological sounding. This simulates the evolution of the buoyant plume particulate cloud that results from an explosive detonation. Particle transport results from deterministically modeled advection and diffusion which is treated as a stochastic process simulated through a discrete Lagrangian Monte Carlo technique. The model was benchmarked against Double Tracks and Clean Slate1 events of Operation Roller Coaster and a 50% agreement was indicated. The dispersed material's particle size distribution may be represented as mono-disperse or as a truncated lognormal distribution. The model's basic outputs are grids of downwind integrated air concentration and mass deposition on the ground. When combined with demographic information and dose conversion coefficients dose and ground deposition outputs are developed to provide information to decision-makers for response and recovery planning.

References:

1. B. A. Boughton, and J.M.Delaurentis, An Atmospheric Dispersion Model for High Explosive Detonations. SAND--92-2069. 1986, Albuquerque: Sandia National Laboratories.

2. B. A. Boughton, and J.M.Delaurentis, An Integral Model of Plume Rise From High Explosive Detonations. SAND--86-2553C. 1986, Albuquerque: Sandia National Laboratories.