Experimental Measurements of Neutron Attenuation in the Advanced Shield Material Ferro Boron in KAMINI Reactor

Shields around core and blankets form major part of reactor assembly in fast reactors. Among the advanced shield materials considered for use in future FBRs, planned to be constructed in India, Ferro-boron is a cheap and indigenously available material. This paper reports the results of experiments conducted in the south end neutron beam of KAMINI reactor on the fast, epithermal and thermal neutron flux attenuation behaviour of Ferro-boron with different percentages of boron as well as boron carbide. The attenuation factors were found over a thickness of 20-30 cm for the measured reaction rates of Pt195 (n,n’) Pt195m, Cd111 (n, n’) Cd111m, Rh103(n,n’) Rh103, In115 (n,n’) In115m, Hf180(n,n’)Hf180m, Cu63 (n,) Cu64, Na23 (n,) Na24, Mn55 (n,) Mn56 and Au197 (n,) Au198 reactions representative of fast, epithermal and thermal neutron fluxes. A comparative analysis with the neutron attenuation behaviour measured in boron carbide powder is also made.