Calculation of kinetic parameters of LFR with the OpenMC Monte Carlo code

This work investigates the different methods used to analyze the effective delayed neutron fraction, $beta_{eff}$, and the effective mean generation time, $Lambda_{eff}$, in the OpenMC code, with a particular focus on Lead-cooled Fast Reactors. The document centres on the implementation of the Iterated Fission Probability (IFP) method in OpenMC. A detailed examination of the theory behind the method, along with the sources of uncertainty, is provided to improve understanding and optimize the method. The IFP method is verified and validated by running simulations and comparing their accuracy with experimental data and other commonly used methods for calculating kinetic parameters. These values are computed for a set of fast neutron reactor facilities that are used as benchmarks by various organizations. In general terms, the IFP method demonstrates correct behavior for this type of calculation, achieving consistent results (less than 10% of relative deviation) that agree with benchmarks and other references and showing good adaptation to optimization (number of latent generations, propagation of incertitude).