Material transport analysis for accident-induced flow in nuclear facilities

This report is a summary of the material transport modeling procedures developed to support a family of accident analysis computer codes. The material transport modeling areas include transport initiation, convection, interaction, depletion, and filtration. Except for material interaction, these areas are developed in modular form in three Los Alamos National Laboratory computer codes: TORAC, EXPAC, and FIRAC. This family of codes was developed to provide improved methods of tornado, explosion, and fire accident consequence assessment, respectively, for the nuclear industry. Although the codes were designed to estimate accident-induced gas-dynamic, thermal, and material transport transient phenomena in nuclear fuel cycle facility ventilation systems, they are applicable to other faciliites as well. Sample problems using TORAC have been provided to illustrate the current material transport capabilities for a simple system under tornado-induced accident conditions. Some suggestions for future improvements to some of these material transport models also are discussed.