Application of Galerkin’s Method to Calculate the Behavior of Boiling Water Reactors During Limit-Cycle Oscillations

A technique for calculating an approximation to the time-dependent power of a boiling water reactor (BWR) during steady-state, low-amplitude limit-cycle oscillations is described. An approximate solution is obtained from the application of Galerkin’s method to a BWR dynamic model consisting of the point-kinetics equations and the power-to-reactivity feedback transfer function; such a feedback transfer function can be obtained from linear frequency domain stability codes, such as the LAPUR code. The approximate solution technique is described, and comparisons of approximate solutions with numerical results and measured data are given. It is concluded from these comparisons that the application of Galerkin’s method to the equations obtained from this particular BWR dynamic model can be used to extend results from a linear frequency domain stability code to calculate nonlinear, time-dependent reactor parameters during low-amplitude limit-cycle oscillations.