IRRADIATION-DRIVEN SOLUTE REDISTRIBUTION IN ZR ALLOYS

Zr-2.5Nb, with four different Fe concentrations, Zircaloy-2 and a Zr(F e) single crystal have been irradiated with energetic Ar+ ions (mostly 1.5 MeV) to fluences less than or equal to 10(21)/m(2) (similar to 10 0 dpa). The resulting enhancement of the alpha-phase Fe solubility has been measured as a function of dose, dose-rate and specimen temperatu re. Most of the chemical analyses were done by electron microprobe. At 50 and 300 degrees C there was a discernible increase in alpha-phase Fe for Zircaloy-2, bur not for Zr-2.5Nb. Between 411 and 469 degrees C the Fe levels in the alpha-phase of both alloys increased to similar to 2500 ppma from prior-irradiation levels of - 70 ppma: in Zr-2.5Nb t hin foils there was a corresponding drop of the beta-phuse Fe concentr ations from about 1.5 to 0.4 at.%.