Effect of Activation Cross Section Change on the Shallow Land Burial Fraction of Low Activation Materials for Fusion Reactors

The radwaste generated from three fusion power reactors using ferritic steel, V-alloy and SiC/SiC composite were classified into low level waste (LLW) which can be disposed by shallow land burial (SLB) and medium level waste (MLW) which cannot be disposed by SLB because one or more of the radionuclides exceeds the derived limiting concentration value. When the recently developed FENDL/A2.0 library is used, the SLB fraction became 91% for ferritic steel, 36% for V-alloy and 65% for SiC/SiC. It is found that if the Nb impurity content in V-. alloy and N impurity content in SiC/SiC could be reduced to 1/100 (0.15 Wt.ppm) and 1/20 (5times10⁻⁴ Wt.%), respectively, the SLB fraction becomes nearly 100% for both materials. On the other hand, the alloying element W content needs to be reduced to further increase the SLB fraction in case of the ferritic steel F82H.