Development of a numerical tool for calculating the fluctuations in PWRs

Other conference contribution, 2011

This paper describes the development of a tool for estimating fluctuations in neutron flux, fuel temperature, moderator density and flow velocity in Pressurized Water Reactors by coupling a dynamic thermal-hydraulic module and a dynamic neutron kinetic module. The code calculates the static solution first, giving the profile of the static fuel temperature, moderator density, velocity and neutron flux. The fluctuations (called noise in this work) are the differences between the actual time-dependent values and the corresponding mean values. The fluctuations are in general induced by perturbations in the thermal-hydraulic parameters, e.g. moderator temperature or density, at the inlet of the core. There is also a possibility to directly define the perturbations in the macroscopic cross-sections and to supply them to the neutronic part of the model.