New scenario for the accumulation and release of radiation damage in rock salt and related materials

Rock salt might be a promising geological medium for a radioactive waste repository. However, we have observed that even a basically stable compound such as NaCl may become unstable after heavy irradiation. As a result of the irradiation, dislocations, Na and Cl2 precipitates and large voids are produced followed ultimately by sudden explosion-driven fracture of the material. We present a new concept of the radiation-induced micro-structural evolution, which explains the phenomena observed in heavily irradiated NaCl samples. This concept can be a prototype of a more general assessment of radiation effects in crystalline radwaste and repository materials, which is necessary for the evaluation of critical effects and maximization of the safety of repositories