Helium damage and helium effusion in fully stabilised zirconia

Nuclear reaction analysis of helium migration in silicon carbide

“…Below 800°C, the measured diffusion constants with an apparent athermal behavior (like D 1 ) were analyzed as effective values, which include diffusion, trapping and detrapping, on the basis of a single diffusion equation [14]. At temperatures higher than 800°C, helium emission from the (He n -V m ) clusters was found and an apparent profile narrowing was observed in both sets of data, in agreement with the data of YSZ polycrystalline ceramics [33]. In this second diffusion regime, helium out gassing is controlled by the gradient of total helium concentration between the sample surface and the trapping zone near the EOR zone.…”

Xenon versus helium behavior in UO2 single crystals: A TEM investigation

“…Thus He diffuses probably via an interstitial mechanism as it was observed in yttria-stabilized zirconia [27]. Conversely the diffusion process of substitutional Xe involves certainly the vacancies created by energetic ions as it was shown by Evans in UO 2 implanted with Kr and Xe ions [7].…”

Helium behaviour in waste conditioning matrices during thermal annealing

“…The total quantity of helium released from the sample is modeled with the assumption that the initial profile is a Gaussian (evidenced by Neutron Depth Profiling for the case of helium implanted in YSZ [12,15,16]. The model is based on Eq.…”