Radiation-induced stored energy in rock salt

Material characterization and modification using helium lon microscopy : various examples

“…A similar effect of enhanced F-center creation was observed in the case of LiF [140,141]. Dislocations are also effective traps for H-centers [126,142] and are able to further enhance F-center formation. However, we do not expect the appearance of dislocations at the applied fluences [72].…”

“…When the current density increases, the events temporally overlap, and the processes that occur are not independent anymore. When the cascade events start to overlap, the high H-center concentration, combined with the high mobility of such centers, increases the probability for the formation of a Cl 2 molecule [108,[140][141][142]. The recombination rate between an F-center and Cl 2 is much smaller than that between F -H centers.…”

New mechanism for radiation defect production and aggregation in crystalline ceramics

“…5 shows the void±crack evolution with increasing irradiation dose and the amount of stored energy in natural rock salt crystals. 2 It is seen that the crack length increases gradually, which can be explained by a combined mechanism of diusion accumulation and explosive release of energy in voids [21], by which the ®nal crack length is determined by the rates of two competing processes, namely, the production and dissipation of heat. In some cases, the former process dominates resulting in a sudden fracture of the material [20,21].…”

“…Important geological applications are related with nuclear waste management, e.g. synthetic ceramic processing of highlevel waste (HLW) in ceramic waste forms and the planned storage of HLW in stable geological formations [1,2]. In Europe these formations are rock salt (NaCl), clay and granite.…”

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

“…Rock salt can store energy of ionizing radiation emitted by HLW in the form of radiolytic products, i.e. colloidal sodium and molecular chlorine, which was the subject of numerous investigations [3][4][5][6][7][8][9], some of them concluding that saturation of radiation damage with increasing irradiation dose occurs well within the acceptable range for repository safety [6,7]. On the other hand, more recent systematic experiments on many heavily irradiated samples have shown that in many doped and natural rock salt samples, the stored energy value increases with increasing dose without any sign of saturation [8] and more important is that large voids are produced, which initiate explosive fracture of the samples [9].…”