Assessment of the neutron activation of a stainless steel sample in a Research Nuclear Reactor using the Monte Carlo method and CINDER’90

Materials in a nuclear reactor are activated by neutron irradiation. When they are withdrawn from the reactor and placed in some storage, the potential dose received by workers in the surrounding area must be taken into account. In previous papers, activation of control rods in a NPP with BWR and dose rates around the storage pool have been estimated using the MCNP5 code based on the Monte Carlo method. Models were validated comparing simulation results with experimental measurements. As the activation is mostly produced in stainless steel components of control rods the activation model can be also validated by means of experimental measurements on a stainless steel sample after being irradiated in a reactor. This has been done in the Portuguese Research Reactor at Instituto Tecnológico e Nuclear. The neutron activation has been calculated by two different methods, Monte Carlo and CINDER’90, and results have been compared. After irradiation, dose rates at the water surface of the reactor pool were measured, with the irradiated stainless steel sample submerged at different positions under water. Experimental measurements have been compared with simulation results using Monte Carlo. The comparison shows a good agreement confirming the validation of models