[en] The PINSIM-MOD1 digital computer code has been developed for (1) simulating the thermal response of both nuclear fuel pins and electrically heated fuel pin simulators to reactor accident environments, (2) determining transient simulator power input, and (3) analyzing the results of simulator experiments. The code is capable of simulating the thermal response of up to four pins and their associated coolant channels. Three interrelated power systems are modeled in the code, which is capable of determining the power for these systems by interpolating user-supplied tables, by solving the point reactor kinetics equations with or without reactivity feedback, by back-calculation from desired pin surface conditions, or by determining the second-order transfer function response to a calculated demand