NMR line shifts and spin-lattice relaxation rates of 89y and 63Cu in YBa2Cu306, 9 were measured in disordered samples irradiated by fast neutrons with a fluence of: q0 = 5 9 10 TM cm -2 ( Tg "s = 70 K), cp ~ 1.2 9 1019 cm -2 ( T ~ ~ 20 K), in order to investigate the evolution of spin susceptibility ,~s under irradiation. According to the data obtained, ,Zs decreases markedly as structural disorder accumulates in the samples. The variation of ~ 91 is related closely to that observed in oxygen-depleted YBa2CU3OT_ 91 compounds with nearly the same T e value. The data for yttrium display some features that are absent in oxygen-depleted samples. The different temperature dependence of the 89y and 63Cu Knight shifts and the increase of the 89y spin-lattice relaxation rate in irradiated samples are discussed in terms of the electron localization effects a¡ in the CuO2 planes due to the radiation-induced structural disorder.

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