ALFRED Lead-cooled Fast Reactor neutronics benchmark

Lead-cooled fast reactors (LFRs) have been identified as one of the most promising Generation IV technologies, leading to the development of the SMR-LFR project in the Belgian Nuclear Research Centre (SCK CEN). Moreover, in order to familiarize with the neutronics of LFRs, the Nuclear Energy Agency (NEA) is organizing a benchmark based on the Advanced Lead-cooled Fast Reactor European Demonstrator (ALFRED). The neutronics benchmark is split into three phases. During the first one, a 2D model is considered to reproduce the geometry of a fuel pin cell. For the second phase, the model is upgraded into a fuel assembly, and in phase 3, the 3D model of the whole core is replicated. In each stage, a criticality analysis is performed, while carrying out calculations of cross sections and the neutron flux. In parallel, sensitivity analysis of k-effective to nuclear data are performed. This allows to determine what are the nuclear data, mostly cross sections, of greatest importance to k-eff. The output sensitivity data is subsequently used to carry out the uncertainty propagation using the sandwich rule. Therefore, the major contributors to the uncertainty in k-eff can be identified. In particular for this thesis, calculations have been performed with Serpent 2, a Monte Carlo code for neutron transport. With regards to the nuclear data, several libraries were considered, including ENDF/B-VIII.0, JENDL-5, JEFF-3.1.1, JEFF-3.3 and JEFF-4. The results obtained are of great value, as they allow to verify different libraries and several codes, when compared with other participant results. The top contributors of the uncertainty are also assessed, giving some insight on which should be the main concerns to guarantee the safe operation of LFRs.