Shielding performance of newly developed boron-loaded concrete for DT neutrons

In order to enhance the neutron shielding performance of concrete in neutron generation facilities from the view point of reduction of effective dose rates in operation and radioactive wastes in decommission, we develop concrete with boron of more than 10 wt%. We perform a neutron shielding experiment using the mockup of the newly developed boron-loaded concrete and DT neutrons at FNS in JAEA, and measure the reaction rates of the 93Nb(n,2n)92mNb and 197Au(n,)198Au reactions in the mockup. The calculations are conducted by using MCNP-5.14 and FENDL-2.1. The calculation results agree well with the measured ones, and we confirm that the accuracy is very good on the atomic composition data of the boron-loaded concrete and their nuclear data. In addition, we calculate neutron and photon effective dose rates and reaction rates of the 59Co(n,)60Co and 151Eu(n,)152Eu reactions, which produce critical radioisotopes in decommission, in the boron-loaded concrete and other concretes with DT neutrons and the experimental condition presently used. The dose rates and reaction rates are drastically reduced by using the boron-loaded concrete and it is concluded that the boron-loaded concrete has very good shielding performance for DT neutrons