Higher Flux Mode Effects in Xenon Spatial Oscillations

The stability of a reactor to xenon-induced spatial power oscillations is generally determined using the first harmonic flux mode alone. This assumption has been tested by including the second harmonic mode in the model and allowing cross coupling between modes. It was found that modal interaction effects are only significant for unstable situations, thus verifying that the use of a single flux mode stability criterion is an adequate approximation to the multimode case.