MCNP model of L-54M nuclear research reactor: validation by preliminary graphite radiological characterization

Abstract

Since its shutdown in 1979, L-54M nuclear research reactor of Politecnico di Milano has been kept in safe storage configuration. In view of forthcoming decommissioning activities, many characterization activities have been performed on its matrices.Regarding the L-54M graphite stack, a neutron activation model was developed and validated by a graphite sampling and preliminary radiological characterization campaign focused on the most significant gamma-emitting radionuclides.Even if slightly underestimating the measured values, between -5% and -49% for 152 Eu, between -41% and -67% for 154 Eu, the simulated activity concentrations promisingly reproduce the experimental radial profile.