EXPERIMENTAL EVALUATION OF NEUTRON SHIELDING MATERIALS

A new proposed design of neutron shielding material-based on the commercial material Borotron UH050 with an addition of Al(OH)3-is evaluated in order to determine if its neutron and gamma shielding properties match those of a reference material, NS4FR. Neutron and gamma dosimetry measurements are performed, as well as neutron spectrometry measurements and Monte Carlo simulations. Negligible differences are found between the materials for neutron shielding, while significant differences are found for gamma shielding. The effect of Al(OH)3 addition to Borotron UH050 is to reduce neutron shielding properties while increasing gamma shielding properties. The resulting material is as efficient as NS4FR for neutron shielding but less efficient for gamma shielding-thicknesses 20% higher are required to match gamma shielding properties of NS4FR. Monte Carlo models of the materials are validated based on the performed measurements of neutron spectra and neutron and gamma ambient dose equivalent.