Neutron attenuation studies with borated polyethylene slabs containing 30% natural boron and its comparison with hydrogenous materials

In fast reactor fuel reprocessing facilities, providing suitable shielding for neutrons is one of the challenging tasks. The material chosen for neutron shielding should have good moderating and absorbing properties. In order to find cost effective prospective materials, a series of neutron attenuation measurements are performed with hydrogenous materials in the south beam end of Kalpakkam Mini (KAMINI) reactor to understand their characteristics. In the present experiment, the neutron attenuating properties of borated polyethylene containing 30 % natural boron are studied. The thermal and fast neutron flux attenuation characteristics of the material are compared with 5% and 10% borated polyethylene and other hydrogenous materials. The thermal/epithermal neutron flux attenuation obtained with 30% borated polyethylene for a thickness of 30 cm is 1.5 times more than 5% and 10% borated polyethylene. Similarly, the fast flux attenuation increases by a factor 1.1 compared to 5% and 10% borated polyethylene. In general if borated polyethylene is used instead of normal polyethylene, 50% reduction in volume of shields can be obtained for thermal and epithermal neutron flux attenuation and 16 to 22% reduction in volume shields can be obtained for fast neutron flux attenuation. (author)