Advanced neutron shielding material using zirconium borohydride and zirconium hydride

Neutron transport calculations have been carried out to assess the capability of zirconium borohydride (Zr(BH 4 ) 4 ) and zirconium hydride (ZrH 2 ) as advanced shield materials, because excellent shields can be used to protect outer structural materials from serious activation. The neutron shielding capability of Zr(BH 4 ) 4 is lower than ZrH 2 , even though the hydrogen density of Zr(B H 4 ) 4 is slightly higher than that of ZrH 2 . High-Z atoms are effective in neutron shielding as well as hydrogen atoms. The combination of steel and Zr(BH 4 ) 4 can improve the neutron shielding capability. The combinations of (Zr(BH 4 ) 4 + F82H) and (ZrH 2 + F82H) can reduce the thickness of the shield by 6.5% and 19% compared to (water + F82H), respectively. The neutron flux for Zr(BH 4 ) 4 is drastically reduced in the range of neutron energy below 100 eV compared to other materials, due to the effect of boron, which can lead to a reduction of radwaste from fusion reactors.