PROBABILITY DISTRIBUTIONS IN SIMPLE NEUTRONIC SYSTEMS VIA FOKKER-PLANCK EQUATION

The Fokker-Planck equation for the neutron density probability distribution in a multiplying system, possessing random source and random parametric excitation, is deduced. It is shown that white noise parametric excitation and white noise source excitation both have the same effect on the functional form of the correlation but that the parametric excitation increases its amplitude. A method for obtaining the correlation function directly from the conditional probability distribution is described and applied to a simple point model equation with one group of delayed neutrons. © 1969.