The primary products of irradiation of alkali halide crystals are anion and cation Frenkel pairs [1–4]. Interaction of these products among themselves and with structural defects existing before irradiation leads to the appearance of various structural defects, the majority of which are optically active. The present study will treat enrichment centers which can be formed from the components of Frenkel cation pairs. Studies of this type are important in providing information on states in which radiation-created cation defects can exist stably in the lattice.