Experimental campaign on ordinary and baritic concrete samples for the SORGENTINA-RF plant: the SRF-bioshield tests

The SORGENTINA-RF project aims at designing and realizing an accelerator-driven 14 MeV fusion neutron source. The bio-shielding of this plant must guarantee a maximum contact dose rate of 10 μSv/h. For radiation protection purposes, baritic concrete is typically used in γ-ray sources. The higher density of the baritic concrete allows to obtain the same attenuation of the ordinary one, but over smaller thicknesses, albeit with higher production costs. In order to verify the effectiveness of the preliminary design of the SORGENTINA-RF neutron source relying on the use of both ordinary and baritic concrete layers, both neutron and γ-ray attenuation measurements were carried out. Neutron measurements were performed at the Frascati Neutron Generator (ENEA Frascati Research Center), while γ-rays measurements were carried out using the Co source of the ENEA Bologna Research Center. The measurements were corroborated by Monte Carlo simulations performed by means of the MCNP6 code. The good agreement between experiments and simulations allowed to establish that the use of a layer of baritic concrete for the SORGENTINA-RF bio-shielding does not appear to be neither advantageous or cost-effective in terms of attenuation of the n/γ radiation field, then suggesting the use of only ordinary concrete for the whole shielding design.