A new methodology in computational micromechanics, dislocation dynamics (DD), is introduced.Dislocation dynamics is developed for examining the dynamic behavior of dislocation distributions in solid materials. Under conditions of externally applied stress, dislocations exhibit glide with a velocity proportional to a power of the applied stress 0. and climb motion with a velocity that is a function of the applied stress and temperature. These motions result from long-range force fields, comprising both externally applied stress and long-range interactions between individual dislocations. Short-range reactions are represented as discrete events. The DD methodology is to be differentiated from particle methods in statistical mechanics (e.g. , molecular dynamics and the Monte Carlo method) in two respects. First, DD is developed to study the dynamical behavior of "defects" in the solid. Generally, the density of defects is less than that of the particles that make up the solid. Second, the small number of dislocations allows for a complete dynamical representation of the evolution of dislocations in the material medium without the requirement of statistical averaging. The purpose of the DD methodology is to bridge the gap between experimentally observed phenomena and theoretical descriptions of dislocation aggregates, particularly the evolution of self-organized dislocation structures under temperature, stress, and irradiation conditions.

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and HA10-after 20 3 achieving a burnup of 3x10 captures/cm (after Hollenberg [2]). . 35 2 Volumetric swelling of LiAlO. exposed to = 5 MW/m of neutron wall loading as a function of irradiation time 39 2 Volumetric swelling of Li,0 exposed to 5 MN/m of neutron wall wall loading as a function of irradiation time 42 Blanket pin average steady state temperature as a function of distance from the first wall for a neutron wall loading of = 5 MW/m 2 45 Helium production in LiAlO, breeder pins as a function of distance from the. first wall 47 Average helium production in Be-rods as a function of distance from the first wall 48 Average volumetric swelling of LiAlO, breeder rods exposed to 2 5 MW/m neutron wall loading after 3 years of irradiation 49 2 Volumetric swelling of Be-rods exposed to 5 MW/m neutron wall loading after 1, 2, and 3 years of irradiation 50 TABLES Summary for blanket material properties current status (12/85) ... Estimates for bubble number densities and radii using above model and experimental swelling data for LiAlO. Experimental and analytical swelling results for LiAlO, for 500 i T 1 900°C 3S Experimental sw511ing and helium retention data for Li 0 iv 5. Estimate for bubble number densities and radii using the above model and experimental data for Li-O 6. Experimental and analytical swelling results for Li.O for 500 < T < 900°C 7. Experimental and analytical swelling results for Be irradiated to

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