Accuracy of the Quasistatic Treatment of Spatial Reactor Kinetics

The quasistatic approach of treating the spatial dynamics problem is described as one method out of a full sequence of methods that factorize the flux into an amplitude and a shape function. The accuracy of these methods is investigated for a wide range of excursions in fast and thermal reactors by comparison with a full numerical solution. The quasistatic method describes even extreme excursions in fast reactors very accurately. Its application to thermal reactor excursions may, however, lead to appreciable errors. The “improved quasistatic” method reduces the errors for both types of reactors to negligible amounts so that its application to thermal reactors may be also considered.