Spills of liquid radioactive material are reviewed as potential event that can be associated with release into the atmosphere. Existing approaches to radiological impact assessment for onsite as well as offsite of facility are presented. The example of using the actual Java version of the European RODOS system as prototype of the decision support system shows the general implementation of the analysis and preparation of initial data in order to model the radiological impact on the public, personnel and environment. Given the specifics of the occurrence of emergency scenarios of this type, features of atmospheric models application, description of the source term model, software integration features, ventilation task solving, completeness and format of the initial data required for radiological consequence modelling.