An intrinsically safe facility for forefront research and training on nuclear technologies — A zero-power experiment

The study of subcritical reactors needs some test to correctly evaluate many parameters that must be introduced in a reactor model. The Sub-critical Multiplication installation at the University of Pavia was used to measure neutron fluxes and multiplication factors that will be modelled with a MCNP Monte Carlo numerical simulation. The comparison between the measurements and the simulations were very promising demonstrating that also in a sub-critical system the Monte Carlo model could be very helpful in describing the reactor characteristics. Using all the collected data from measurements and simulations, it was possible to determine the keff of the reactor plant with a reasonable accuracy. The ratio between the fast and the thermal component of the neutron fluxes was also determined.