Shielding efficiency of metal hydrides and borohydrides in fusion reactors

Abstract

Mass at ten u a tion co ef fi cients, mean free paths and ex po sure buildup fac tors have been used to char ac ter ize the shield ing ef fi ciency of metal hy drides and borohydrides, with high den sity of hy dro gen. Gamma ray ex po sure buildup fac tors were com puted us ing five-pa ram e ter geomet ric pro gres sion fit ting at en er gies 0.015 MeV to15 MeV, and for pen e tra tion depths up to 40 mean free paths. Fast-neu tron shield ing ef fi ciency has been char ac ter ized by the ef fec tive neu tron re moval cross-sec tion. It is shown that ZrH 2 and VH 2 are very good shield ing ma teri als for gamma rays and fast neu trons due to their suit able com bi na tion of low-and high-Z el e ments. The pres ent work should be use ful for the se lec tion and de sign of blan kets and shield ing, and for dose eval u a tion for com po nents in fu sion re ac tors.