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Early experimental data on void swelling in electron-irradiated materials disagree with the dislocation bias models based on the dislocation-point defect elastic interactions. Later, this became one of the factors that prompted the development of models based on production bias (PBM) as the main driver for swelling, which assumed that the dislocation bias was much lower than that predicted by theoretical analyses of dislocation bias. However, the PBM in its present form fails to account for important and common observations, namely, the indefinite void growth often observed under cascade irradiation and the swelling saturation observed under high-dose irradiation and in void lattices. In this paper, we show that these contradictions can be naturally resolved in the framework of the rate theory that accounts for the radiation-induced vacancy emission from extended defects, such as voids, dislocations and grain boundaries. This modification introduces a new bias type in the theory, namely, the emission bias. This modified rate theory agrees well with the experimental data and demonstrates that the original dislocation bias should be used in rate theory models along with the emission bias in different irradiation environments. The modified theory predictions include, but are not limited to, the radiation-induced annealing of voids, swelling saturation under high-dose irradiation, generally, and in void lattices, in particular.

The irradiation hardening of reactor pressure vessel steels due to the formation of dislocation loops is analyzed. The analysis is based on the original model for the nucleation and subsequent evol...

A new mechanism of irradiation creep is proposed, which is based on the radiation and stress induced difference in emission (RSIDE) of vacancies from dislocations of different orientations with respect to the external stress. This phenomenon is due to the difference in vacancy formation energies, which is proportional to the external stress. The proposed model exhibits similarities with thermal creep models and it is distinct from stress-induced preferential absorption (SIPA) models based on the difference in the long-range interaction of point defects with dislocations. The RSIDE creep rate is essentially temperature independent and is proportional to the dislocation density, stress and irradiation flux. It is inversely proportional to the square of the vacancy formation energy, which is lower than the Frenkel pair formation energy. Experimental verification of the proposed model is discussed on the basis of the measurements of vacancy concentration and creep rate under sub-threshold electron irradiation.

We report on the results of computer simulation of point defect production near voids in crystalline Cu at primary knock-on atom (PKA) kinetic energies ranging from 5 to 1000 eV. The PKA energy dependence of numbers of created defects are revealed. The threshold energy for a stable vacancy formation is found to be much smaller than that for an interstitial atom, which results in a biased formation of vacancies in the void proximity in the whole investigated range of PKA energies. Dissolution of small voids by subthreshold irradiation is simulated. The impact of considered radiation effects on kinetics of radiation damage is discussed.

Until recently researchers focused attention mostly on determining the causes of aggression rather than on the search for ways to prevent or to reduce it. On the one hand this can be explained by the widespread conviction that we already know the most effective ways to prevent aggressive actions, namely punishment and catharsis; and, on the other hand, by the notion that aggression can be reduced by getting rid of the factors that give rise to manifestations of it [3; 6].

Experimental and the oretical results are presented on the formation of voids discovered recently in havily irradiated NaCl. Experimental data show that for NaCl samples with particular dopants, the development of radiation damage, such as Na-colloids, chlorine inclusions and voids does not show a saturation as a function of the dose. A quantitative comparison of the new model (Dubinko et al., These proceedings) for radiation damage in alkali halides with experiemental data is presented. Mean sizes and volume fractions of all types of observed defects are calculated. It is shown that voids formed due to agglomeration of F centers and cation vacancies can grow to the dimensions exceeding the mean distance between colloids and bubbles, eventually absorbing them, and, hence, bringing the halogen gas and metal to a back reaction. Impurities are shown to play a major role in the void development with increasing irradiation dose, which strongly affects the radiation stability of NaCl.

We consider diffusion in a medium with randomly fluctuating diffusion coefficient. An equation is derived for diffusate concentration averaged over dimensions exceeding those of fluctuations. In the case when fluctations are weak and their correlation scales small the equation is reduced to a differential one, where the effective diffusion coefficient is always lower than the average one. A stability criterion for uniform distribution of diffusate is derived. Some implications of the theory for the radiation effects in solids are discussed.

The theory of gas bubble lattice that is formed under irradiation by light gas ions is developed. To explain the ordering, a new mechanism of bubble interaction is proposed which is based on the loop-punching from growing bubbles. The symmetry and alignment of the bubble lattice are explained, its stability criteria are derived and characteristic parameters are estimated.