Learnings from a Joint-Italian-Belgian Neutronic characterization of the TAPIRO source reactor

In the scope of an Interlaboratory Consulting agreement between the ENEA and SCK/CEN Laboratories, an extensive neutronic characterization of the Tapiro source reactor at Casaccia, Italy, has been carried-out. This does encompass the cylindrical enriched uranium core, its surrounding copper reflector and, for some sensors, part of the outer concret shield. A large array of equivalent fission flux and reaction rate measurements have been performed and experimentally normalized to a unit core-integrated neutron source strenght; this covers the entire energy range of practical interest, from ~100 eV to ~10 MeV. Tapiro provides a family of neutron spectra of extremely variable hardness, most suitable to many reactor metrology applications, and amenable to good geometrical modeling. The accuracy of a transport theory evaluation of these reference neutron fields primarily depends on th e quality of copper neutronic cross-sections. to supplement the Tapiro experimental data bank in this last respect, a supportive copper shell benchmark has been built at Mol within a 33-type natural uranium driver source shell at the centre of the one-meter spherical cavity in BR1 graphite thermal column. This overview highlights the Tapiro neutronic characterization results, with emphasis on learnings deemed to be of broader interest to reactor physics and neutron dosimetry concerns.