Numerical tools applied to power reactor noise analysis

Paper i proceeding, 2006

In this paper, the development of numerical tools allowing the determination of the neutron noise in power reactors is reported. These tools give the space-dependence of the fluctuations of the neutron flux induced by fluctuating properties of the medium in the 2-group diffusion approximation and in a 2-dimensional representation of heterogeneous systems. Some applications of these tools to power reactor noise analysis are then described. These applications include the unfolding of the noise source from the resulting neutron noise measured at a few discrete locations throughout the core, the study of the space-dependence of the Decay Ratio in Boiling Water Reactors, the noise-based estimation of the Moderator Temperature Coefficient of reactivity in Pressurized Water Reactors, the modeling of shell-mode core barrel vibrations in Pressurized Water Reactors, and the investigation of the validity of the point-kinetic approximation in subcritical systems.