[en] The objective of this study is to examine the usefulness and effectiveness of currently existing models that simulate the release of uranium hexafluoride from UF₆-handling facilities, subsequent reactions of UF₆ with atmospheric moisture, and the dispersion of UF₆ and reaction products in the atmosphere. The study evaluates screening-level and detailed public-domain models that were specifically developed for UF₆ and models that were originally developed for the treatment of dense gases but are applicable to UF₆ release, reaction, and dispersion. The model evaluation process is divided into three specific tasks: model-component evaluation; applicability evaluation; and user interface and quality assurance and quality control (QA/QC) evaluation. Within the model-component evaluation process, a model's treatment of source term, thermodynamics, and atmospheric dispersion are considered and model predictions are compared with actual observations. Within the applicability evaluation process, a model's applicability to Integrated Safety Analysis, Emergency Response Planning, and Post-Accident Analysis, and to site-specific considerations are assessed. Finally, within the user interface and QA/QC evaluation process, a model's user-friendliness, presence and clarity of documentation, ease of use, etc. are assessed, along with its handling of QA/QC. This document presents the complete methodology used in the evaluation process