In order to test the reliability and compatibility of first-wall/blanket components for a fusion engineering test reactor, it is important to determine the interactive effects between properties of different materials which are in contact or close proximity. This paper describes an approach to the selection and design of subscale interactive testing for fusion nuclear components, and gives two examples of interactive tests which can be performed in current fission- and accelerator-based neutron sources. The goal of these interactive tests is to analyze the behavior of nuclear components (such as the first wall and blanket) in a fusion engineering test reactor in order to verify predictions of their lifetimes and failure modes.