[en] The fuel rod analysis computer program (FRAP-T) has been modified to analyze transient fuel rod behavior in the gas cooled fast reactor (GCFR). Major features modeled include the effects of helium coolant, ribbed cladding, pressure equalization system, and 316 stainless-steel material properties. The code capabilities include models of elastic-plastic-creep deformation behavior, two-dimensional heat conduction, rod ballooning, and transient axial gas flow. The models are particularly relevant to GCFR transient analysis in that partial or full blockage of the pressure equalization system could cause a significant pressure differential to exist during a helium depressurization, the GCFR design basis accident. An analysis of the design basis accident illustrating the predictive capabilities of the code is presented