In the framework of a collaboration between Idaho National Laboratory (INL, USA) and the Department of Astronautical, Electrical and Energy Engineeing (DIAEE) of Sapienza, the Nuclear research group of DIAEE is a contributor for the developing of the ¿Parallel and Highly Innovative Simulation for INL Code System¿ (PHISICS), a neutronic (NK) toolkit intended to provide a modern analysis tool for reactor physics investigations. PHISICS is capable to work coupled with RELAP5-3D®, the reference thermal hydraulic code for transient analyses in nuclear reactors, developed by INL. The analyses for fast reactors need the using a large number of energy groups for the neutrons, in comparison with the actual four groups as the default RELAP5-3D® neutron kinetic solver. In addition, thanks to the proposed coupling, detailed 3D thermal hydraulic (TH) transient analysis with a full 3D transport (or diffusion) neutronic will be possible.
The capability to perform TH-NK coupled calculations is one of the main open topics in the GEN IV fast reactors development. This research would realize a complete methodology by using the state-of the art tools, capable to analyze also the unprotected and dissymmetric transient analyses, with a reduction of uncertainty margins.
An optimization of the coupling, object of this proposal, is needed for this kind of calculations, because of the required very large number of nodes and time step, which would make not feasible a simulation, even by exploiting a powerful computing cluster.
A validation of this coupling will be performed through a comparison with the results of an experimental test performed during the ¿Sodium Natural Circulation Test¿ in the framework of ¿PHENIX End-of-Life Experiment¿, selected for a IAEA (International Atomic Energy Agency) benchmark.
Risk Analysis Virtual ENvironment (RAVEN) code will be used as sensitivity and uncertainty evaluation tool for the calculations and for a statistical comparison with experimental data.
