The ANET code: from high energy physics to stochastic dynamic neutronics with thermal hydraulic feedback

ANET is being developed targeting to a multiple capabilities code which can inherently, dynamically and accurately simulate GEN II/III reactors as well as Accelerator Driven Systems (ADSs). ANET is oriented towards an open- source pure Monte-Carlo transient code with Thermal-Hydraulics (T-H) feedback. It incorporates the treatment of all types of particles' creations and collisions as existing in the High Energy Physics code GEANT while its capabilities have been extended to energies below 20 MeV so as to cope with fission neutrons and their possible reactions in a reactor core (transport, elastic and inelastic scattering, capture and fission). The developed code aims to account for core evolution in both short and long time-scales, allowing for T- H feedback and assessment of the fuel isotopic composition variations, including neutron poisons' evolution. In order to analyze ADSs, ANET can incorporate specific codes (such as FLUKA and INCL/ABLA) for the treatment of spallation targets of various materials and geometries. Regarding verification and validation (V&V) studies ANET has been successfully tested against measurements and/or independent numerical results with respect to its capability to compute criticality, neutron fluence and reaction rates. Also ANET neutron yield computations for three of the most popular spallation target materials (Pb, W and U) hit by accelerated protons of various energies are satisfactorily compared with independent simulations and experimental results. Moreover, preliminary ANET applications for the prediction of changes in the fuel isotopic composition show encouraging results compared with measurements as well as corresponding simulations. (author)