In reactor physics calculations, the measurement of kinetic parameters has an important influence on control and safety analysis of a nuclear reactor. The most important kinetic parameters of nuclear reactors are the effective delayed neutron fraction (βeff), the prompt removal lifetime (τ r) and the mean neutron generation time (Λ). In this study, the kinetic parameters of the Moroccan TRIGA Mark-II reactor were calculated using the 3-D continuous-energy Monte Carlo code MCNP5. The geometrical structure of the Moroccan reactor core and the fuel configuration were designed. The MCNP Results of these parameters are analyzed and compared with references data.

The influence of variation in the kind of material of neutron reflector elements on the core neutronic parameters of the Moroccan Triga Mark-II research reactor was examined. The comparison was made between three kinds of reflector element materials: graphite, beryllium, and beryllium oxide. MCNP5 Monte Carlo computations of the effective neutron multiplication factor ( k ef f ) of the reactor according to the number of reflector material elements inserted in the reactor core for these three reflector elements materials families were carried out. The results found could be used in order to increase the k ef f parameter without changing the size of the reactor.

The measurement of neutronic parameters in nuclear reactors has an important influence on control and safety of nuclear reactor. The effective multiplication factor (keff) is the most important neutronic parameter for determining the state of reactor. This parameter strongly depends of the reflector elements loaded in the reactor core and the outer reflector thickness that surrounds the core. The main purpose of this work is using the Monte Carlo simulation via the MCNP5 code to evaluate the reflector effect of the Moroccan TRIGA Mark-II research reactor on the keff value. For this goal, the geometrical structure of the reactor and the fuel configuration were designed. The MCNP5 calculations of keff parameter of the reactor varying with reflector thickness have been performed. The obtained results are analysed and discussed.