SWIFT HEAVY ION IRRADIATION EFFECTS ON He AGGLOMERATION IN ZrN AND TiZrN CERAMICS

Abstract

The development of novel materials with future nuclear applications is of ongoing concern.As part of this investigation we address two major issues concerning such applications. Firstly, improving the performance of structural materials in the reactor core for new and existing reactors and also the processing and storage of nuclear waste. Nanocrystalline-ZrN and -TiZrN have been identified as candidate materials for inert matrix fuel hosts and as a coatings for structural materials respectively. These materials will experience high levels of different types of radiation in the reactor core such as fission fragments and α-radiation. The effects of different types of radiation on the long term stability of these materials however still needs to be determined. The effects of fission fragments are simulated by means of swift heavy ion implantation and α-radiation by He implantation. The combined effects of SHIs and He on these materials is also studied, since recent studies have indicated that SHI irradiation may significantly modulate hydrogen and helium behaviour in materials. ZrN and TiZrN samples were implanted with 30 keV He and 167 MeV Xe and in some cases also 695 MeV Bi, the samples were subsequently annealed to temperatures between 600 and 1000 °C for 20 minutes. The microstructure of the annealed samples was investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) before and after SHI implantation. Results indicated that post irradiation heat treatment induces exfoliation at a depth that corresponds to the end-of-range of 30 keV He ions, however the formation of blis-ters was suppressed after irradiation with SHIs. It is also important to note that latent ion tracks were not observed in any of the samples.