Ricerc@Sapienza

For the purposes of fission fast reactors analysis, the presence of an intense neutron flux within the core leads to the need of neutron kinetic and thermal hydraulic (NK/TH) coupled simulations to study operating and accidental conditions which may interest the nuclear power plant (NPP). The capability to perform such calculations is one of the main open topics in the Generation IV (GEN IV) fast reactors development. In the framework of a collaboration between Idaho National Laboratory (INL, USA) and the Sapienza Department of Astronautical, Electrical and Energy Engineering (DIAEE), the nuclear engineering group of DIAEE is a contributor for the developing of PHISICS (Parallel and Highly Innovative Simulation for INL Code System), a reactor analysis toolkit to perform advanced neutron transport calculations. PHISICS is capable to work coupled with RELAP5-3D®, the reference thermal hydraulic code for transient analyses in nuclear reactors, developed by INL. Thanks to the proposed coupling, symmetric and non-symmetric transients can be studied by using detailed 3D thermal hydraulic and 3D transport (or diffusion) neutronic models. A validation of this coupled approach is the object of this proposal and will be performed through the comparison with the results of a loss of flow without scram (LOFWOS) test performed in 1986 in the American facility of Fast Flux Test Facility (FFTF) during the passive safety demonstration program. In 2017, the International Atomic Energy Agency (IAEA) selected LOFWOS Test #13 for an international benchmark (CRP I32011 in the framework of IAEA Nuclear Power Programme). DIAEE will participate to this benchmark.