[en] The Fuel Disruption (FD) program at Sandia National Laboratories (SNL) has provided data from over 30 in-pile experiments on the timing and character of initial fuel disruption under simulated liquid metal fast breeder reactor (LMFBR) accident conditions. As part of the FD program, the SANDPIN fuel pin behavior code has been developed to help interpret the observed experiment results and to apply the understanding gained from these experiments to the analysis of LMFBR hypothetical accidents. This paper describes the fission-gas behavior modeling in the SANDPIN code and presents a comparison of SANDPIN predictions with the results of selected FD experiments