Non-linear noise theory for the fluidized bed light water reactor

A non-linear neutron noise theory for zero-power and power mode operation is developed for a fluidized bed light water reactor which operates with a reactor core consisting of a large number of spherical, slightly enriched UO 2 -fuel elements. These fuel pellets have a diameter of 0.8-1.0 cm and are fluidized in a water bed to the optimum moderator-volume to fuel-volume ratio. By means of an experimental loop the reactivity driving force, giving rise to a potentially noisy reactor type, was identified and a method is proposed with which one can evaluate experimentally whether or not such a reactor type could be licensed. Furthermore some numerical results are presented which show that the quadratic term of the reactivity driving force does not excite the noise level but die out with time.