The Spills Working Group is one of 6 working groups under the DOE-DP Accident Phenomenology and Consequence (APAC) methodology evaluation program. Objectives are to assess methodologies available in this area, evaluate their adequacy for accident analysis at DOE facilities, identify development needs, and define standard practices to be followed in the analyses supporting facility safety basis documentation. The group focused on methodologies for estimating 4 types of spill source terms: liquid chemical spills and evaporation, pressurized liquid/gas releases, solid spills and resuspension/sublimation, and resuspension of particulate matter from liquid spills. Computer models were identified with capabilities for quantifying release rates or released amounts from spills, and a set of sample test problems was established for evaluating a specific model for some common or probable accident release scenarios. The group agreed on a set of recommended computer codes which are classified according to spill type and hazard category. Code results for a given problem varied by up to an order of magnitude; this is attributed to differences in how the physics and thermodynamics of the problems were treated by the models
