The origins and goals of the advanced fluid dynamics model (AFDM) program are described, and the models, algorithm, and coding used in the resulting AFDM computer program are summarized. Two boiling pool calculations are presented, the first of an experiment with volume-heated water, the second of a sample fuel/steel pool that is compared with a similar SIMMER-II calculation. A subjective assessment of the AFDM developments is given. It is concluded that a future severe accident code development program might be more oriented toward identification of generic or typical accident sequences rather than attempting to address all uncertainties.