This paper presents a consequence analysis for a postulated fire accident on a building containing plutonium when the resulting outside release is partly through the ventilation/filtration system and partly through other pathways such as building access doorways. When analyzing an accident scenario involving the release of radioactive powders inside a building, various pathways for the release to the outside environment can exist. This study is presented to guide the analyst on how the multiple building leak path factors (combination of filtered and unfiltered releases) can be evaluated in an integrated manner starting with the source term calculation and proceeding through the receptor consequence determination. The analysis is performed in a two-step process. The first step of the analysis is to calculate the leak path factor, which represents the fraction of respirable radioactive powder that is made airborne that leaves the building through the various pathways. The computer cod e of choice for this determination is MELCOR. The second step is to model the transport and dispersion of powder material released to the atmosphere and to estimate the resulting dose that is received by the downwind receptors of interest. The MACCS computer code is chosen for this part of the analysis. This work can be used as model for performing analyses for systems similar in nature where releases can propagate to the outside environment via filtered and unfiltered pathways. The methodology provides guidance to analysts outlining the essential steps needed to perform a sound and defensible consequence analysis
