Computer simulation of radiation damage in NaCl by using a kinetic rate reaction model

The formation of radiation damage in NaCl has generated interest because of the relevance of this damage to the disposal of radioactive waste in rock salt formations. In order to estimate the long term behaviour of a rock salt repository, an accurate theory is required, describing the major processes of radiation damage in NaCl. In 1977, Jain and Lidiard presented a rather simple model which, until now, has served as a means for long term predictions of rock salt repositories. Although the model of Jain and Lidiard describes many experimental results on colloid growth in NaCl reasonably well, it describes the early stages of colloid growth and the effect of impurities on colloid growth less well. The model presented in this paper is an extended version of the Jain-Lidiard model; its extensions comprise the effect of impurities and the colloid nucleation stage on the formation of radiation damage. The new model has been tested against various experimental data obtained from the literature and accounts for several well known aspects of radiation damage in alkali halides which were not covered by the original Jain-Lidiard model. The new model thus may be expected to provide more reliable predictions for the build-up of radiation damage in a rock salt nuclear repository. (orig.)