A simple theory of radiation enhanced diffusion has been worked out which describes the dependence of this enhancement on flux and temperature under steady-state conditions. The theoretical study also shows that the measurement of enhanced diffusion as a function of temperature can indicate the mechanism by which defects are removed from the lattice. Alpha-brass was chosen for the experimental work because it is a kinetically simple system, not complicated by nucleation, in which diffusion is easily followed by measuring the electrical resistivity changes associated with changes in short-range order. The enhanced diffusion rate during irradiation in the Brookhaven reactor has been measured in this alloy at several temperatures in the range 0 to 190°C. This enhancement is independent of temperature from 0 to 150°C, in excellent agreement with the theoretical predictions for the case where the radiation induced defects finally disappear at internal surfaces. Some implications of radiation enhanced diffusion and suggestions for further study are also discussed.

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The kinetics of the annealing of point defects, either by migration to sinks or by recombination, is complicated by the occurrence of a variety of simultaneous r e x t i o n s. An extensive theoretical study of annealing processes is in progress at Brookhaven based on the isolation and combination of siaple kinetic steps. solutions have been used to obtain useful approximations and t o deternine their regions of validity. have bcen studied; the simultaneous annealing of single and divacancies, and the annealing of stngle vacancies with impurity trapping. Three reconbination reactions have been investigated; vacancy-interstitial elmihilation with interstitial migration to sinks, di-interstitial formation, and interstitial trapping at Lmpurities. When analytic solutions could not be found, computer Two migration reaction schemes *

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