This chapter talks about data of defect reactions of the AgxAl1-x alloy system. Defect reactions have been investigated within the α-phase of this Ag-Al alloy system (x = 0.925, 0.885, 0.845) by residual electrical resistivity measurements after electron irradiation, quenching, fast neutron irradiation and in thermal equilibrium. Superannealing is observed for the irradiated samples at temperatures below 100 K; this behaviour indicates SIA migration at these low temperatures and demonstrates in addition that SIA migration can change the degree of SRO in this alloy (interstitialcy mechanism). Due to the change of SRO also vacancy migration can be detected even for very low vacancy concentrations. For the Al-rich side of the phase diagram (x = 0.04) the annealing of irradiation defects is very similar to that of dilute Al alloys.