Studies on the shielding properties of polyboron and ilmenite-magnetite concrete using a reactor neutron beam

The shielding effectiveness of locally developed poly-boron and ilmenite-ma gnetite (I-M) concrete is investigated using the reactor neutron beam of th e 3-MW TRIGA Mark II research reactor at the Atomic Energy Research Establi shment, Savar, Dhaka. The effective removal cross sections for the foregoin g individual shielding materials as well as their combinations are obtained from transmission data using two-group neutron fluxes defined by a Cd-cuto ff value. The experimental transmission factors for I-M concrete and polybo ron are compared with those obtained from transport calculations performed with the ANISN deterministic code in the forward mode and the MCNP4B Monte Carlo code. The ANISN code is used for the fast neutron group flux (Cd-cuto ff flux), and the MCNP4B code is used for the total neutron flux. The agree ment between the experiment and calculation is fairly good at deep penetrat ion, but at initial points, some disagreement is observed. This observation is valid for both polyboron and I-M concrete.