Full Core Criticality Modeling of Gas-Cooled Fast Reactor using the SCALE6.0 and MCNP5 Code Packages

The Gas-Cooled Fast Reactor (GFR) is one of the reactor concepts selected by Generation IV International Forum (GIF) for next generation innovative nuclear energy systems. It was among a group more than 100 prototypes and his commercial availability expected 2030. GFR has common goals as rest GIF advanced types: economy, safety, proliferation resistance, sustainability. Several fuel design such plates, rod pins pebbles are currently being investigated in order to meet high temperature constraints characteristic working environment. In previous study we have compared depletion results heterogeneous assembly (FA), obtained with TRITON6 sequence SCALE6.0 MCNPX-CINDER90 TRIPOLI-4-D codes. Present work continuation neutronic criticality analysis FA full core configurations concept using 3-D Monte Carlo codes KENO-VI/SCALE6.0 MCNP5. based on hexagonal mesh rods (uranium plutonium carbide fuel, silicon clad, helium gas coolant) axial reflector thickness varied purpose optimization. Three materials were analyzed: zirconium (ZrC), (SiC) natural uranium. ZrC been material, having best contribution neutron economy reactivity core. safety parameters also analysed: negative coefficient verified heavy metal coolant density loss. Criticality calculations different active heights performed adjusted. Finally, fixed height done find optimal Shannon entropy fission distribution proved be useful technique monitor both source convergence (stationarity) eigenvalue (keff) fundamental eigenmode All ENDF/B-VII.0 library. showed similarity reference results.