NEUTRON NOISE CALCULATIONS IN THREE-DIMENSIONAL SYSTEMS

Paper i proceeding, 2011

In this paper, the neutron noise, i.e. the stationary fluctuations of the neutron flux around its mean value, is calculated in three dimensions and two energy groups using diffusion theory. Cross-sections and other reactor parameters are realistic data coming from a commercial PWR. This work is an extension of a previous model which used finite differences in two dimensions for the spatial discretization. In this work, the calculations are still performed using finite differences for the spatial discretization, but the neutron currents and neutron noise currents are corrected using the Analytical Nodal Method. Another correction is performed by introducing discontinuity factors to improve the modelling of leakages at the face between the fuel assemblies.