The nuclear data basis for elemental substitution in vanadium alloys and steels

The relationship between composition and residual activation in a number of potential fusion first wall/blanket materials, namely stainless steels, vanadium alloys, Inconel and Zircaloy, is explored by means of a simple graphical approach. Since the main constituent of an alloy provides an essentially fixed reference level, the influence of candidate alloying additions is highlighted by the contribution each of them makes to a particular activation parameter, such as the specific activity, dose rate or heat output, relative to the contribution from the alloy base metal. This approach readily reveals the most critical parameters and post-exposure times with respect to safety and environmental objectives and, in addition, the opportunities for optimizing the activation behavior through elemental substitution.