ENERGY STORED IN IRRADIATED NACL

Recently reported measurements made by Jenks and Bopp (1974, 1977) of the energy stored in heavily irradiated NaCl are reviewed in the light of recent understanding of radiation-damage processes in this material It is shown that, in the ranges of temperatures and dose rates of these experiments, the F-centres produced by the irradiation are retained principally in the form of colloids: the stored energy is thus a direct measure of the number of P-centres retained in this form. Comparison of these results with the predictions of the recently proposed theory of colloid growth (Jain and Lidiard 1977) shows that the predictions of the dependence of colloid growth rates upon temperature and dose rate are qualitatively correct. The dependence of stored energy upon dose, however, appears to require the inclusion of a thermally activated back-reaction and possible modifications to the theory are briefly discussed. However, further experiments in this range of temperatures and dose rates are necessary for more quantitative tests of the theory. This reconsideration of the data of Jenks and Bopp (1974, 1977) does not alter their broad conclusion as to the relative insignificance of stored energy in a natural salt formation used as a radioactive waste repository, although more extensive measurements permitting a more exact test of theory would allow better predictions to be made for such applications. © 1979 Taylor & Francis Group, LLC.