An axial xenon oscillation model

Abstract A two-point xenon oscillation model was developed for PWRs. The model employs the nonlinear xenon and iodine balance equations and the one group, one-dimensional neutron diffusion equation having nonlinear power reactivity feedback. A two-term spatial harmonic series solution was assumed for the flux, xenon and iodine distributions. The system was made as close to critical as possible with the assumed distributions using a variational principle. The xenon and iodine concentrations were then obtained from their governing differential equations. The input/output nature of the model makes it ideal for simulation of xenon-induced reactor transients. A comparison of the simulated plant to actual plant data was made. The period of oscillation, stability index and flux amplitude of the simulated plant were all found to match the actual plant data with less than 10% error.