Fission Matrix Interpolation For The Tfm Approach Based On A Local Correlated Sampling Technique For Fast Spectrum Heterogeneous Reactors

Abstract : Reactor safety analysis requires complex coupled multiphysics calculations modeling the full coreevolution during various accidental situations. Such calculation codes rely on physical models adapted to the physics of the simulated reactor concept. In this frame, the innovative Transient Fission Matrix (TFM) neutronic approach, based on a conversion of the Monte Carlo response in Green functions characterizing the local transport in the reactor and initialy developed for other kinds of reactors, has been successfully applied on one dimensional sodium fast reactors using the correlated sampling technique as detailed in this article. This method takes into account the sensitivity of the neutron transport to local perturbations in order to estimate on the fly the matrices variations due to a given perturbation distribution. This model provides an accurate estimation of the reactivity and of the power distribution in the core during the accident, including the influence of the sodium density distribution in the plenum. This article also illustrates the applications of this neutronic model on sodium fast reactors for small to large perturbations of the system, and point kinetic feedback coecients evaluations.