Concrete Modeling for Neutron Transport and Associated Sensitivity Studies Performed at the AMANDE-MIRCOM Facility

Concrete plays a major role in nuclear facilities as protection against radiation. However, its chemical composition, which is fundamental, is often unknown. Several concrete samples, extracted from the AMANDE-MIRCOM Institute for Radiological Protection and Nuclear Safety (IRSN) facility, were analyzed. Various simulations were performed in order to evaluate the neutron fluence behind a 40-cm-thick concrete wall. These simulations were compared to experimental measurements performed with a Bonner sphere spectrometer and a neutron survey meter. No set of parameters tested was able to produce a simulation accurately matching all the experimental results, but sensitivity studies on several parameters highlight that the three most sensitive parameters are the hydrogen content, the density, and the concrete inhomogeneity. To improve the agreement between the simulations and the measurements, the concrete inhomogeneity modeling should be studied further. Nevertheless, using concrete compositions that are close to reality, especially for hydrogen content, is crucial to correctly simulate neutron transport.