Feasibility study for design and utilization of a cold neutron irradiation facility at the JSI TRIGA reactorCuellar Fernandez, Diego Martín (Avtor) Žerovnik, Gašper (Mentor) Suikkanen, Heikki (Komentor) Neutron transportCold neutronsNuclear reactionsNeutron scatteringNeutron absorptionCross sections.According to some conventions, cold neutrons range from energies of 0.1 meV to 5 meV. Within this energy range, the cross sections for scattering and radiative capture are clearly outside the neutron resonance region. The need for increased accuracy in these cross section values arises from the discrepancies between different evaluated nuclear data libraries (ENDL) and experimental neutron cross section data. In this regard, a design of a cold neutron source using neutrons originating from the JSI TRIGA reactor core is proposed. A parametric study of this irradiation facility is performed using the computer code OpenMC for neutron transport calculations. Neutron beam is sampled and directed through a guide tube with a cold temperature moderator at the beginning, made of graphite or light-water. At first, the simulation is done for a facility in the absence of targets, where energy spectra and cold neutron flux fractions are obtained and evaluated, using moderator thickness and temperature as degrees of freedom. Then, for selected thickness of 70 cm in graphite and 20 cm in H2O, where the cold neutron fluxes were found to be high, the evaluation is made at different temperatures of interest and the highest cold neutron fluxes were found at around 20 K and 58 K respectively for the moderators With the combination of these moderator thicknesses and temperatures, targets of 207Pb and 241Am were added and the scattering and absorption reaction rates were obtained in the simulation, leading to the calculation of their respective cross sections over the cold energy range.20232023-09-21 08:15:03Magistrsko delo/naloga150625sl