Characterization of neutron fields at Cernavoda NPP

In the environment near a nuclear reactor, a fuel container or a particle accelerator, mixed neutron/gamma fields are very common, necessitating routine neutron dosimetry. Accurate neutron dosimetry is complicated by the fact that the neutron effective dose E and neutron personal dose equivalent Hp(10) is strongly dependent both on the neutron energy and the direction distribution of the neutron fluence. Therefore, neutron field characterization is indispensable if one wants to obtain a reliable estimate for the neutron dose. A measurement campaign in CANDU NPP in Cernavoda, Romania, was set up in November 2010 to characterize the neutron fields in four different locations and to investigate the behavior of different personal neutron dosemeters. Neutron field characteristics, such as energy and angular distributions, were determined using different neutron monitors. The energy distribution was measured using a BTI Mycrospec and Nprobe combination, the angular distribution was measured by placing personal dosemeters on five faces of a slab phantom. The results were combined together to obtain a reference value for the personal dose equivalent Hp(10). The obtained values were compared to the readings of the personal monitors in order to choose a suitable neutron dosimetry system at Cernavoda nuclear power plant.