A method for rapid numerical simulation of transient radial heat transfer in nuclear fuel pins is presented. The method is based on a z-transfer matrix formulation of the transient conduction equations and assumes constant physical properties. The elements of the z-transfer matrix are obtained from Laplace transfer functions that are polynomial approximations to the exact equations over a specifiable frequency band, weighted to a better fit in the least-squares sense for frequencies for which inputs are expected to have higher amplitudes than for frequencies for which amplitudes of inputs are expected to be lower. Examples that demonstrate the method suitable for a large number of the transients encountered in plant dynamic analysis are presented.