HIGH-TEMPERATURE H AND D BEHAVIOR IN SOLID AND LIQUID BERYLLIUM

We present the salient features and interpretations from a multi-technique study of the high temperature H isotope behaviour in Be, including liquid Be. The effects of the implantation of If or D ions in Be at 300 to 983 K as well as the effects of in situ annealing in the transmission electron microscope and annealing with a 30 ns laser pulse were investigated. Quantitative measurements of the gas release, ion-beam depth profiling, scanning electron and atomic force microscopy, and numerical modeling were used in the analysis. For H/Be < 14%, the H trapping energy is 1.7 eV and diffusion out of the sample is effectively 10 times faster than anticipated from other work. The release is not connected with blister rupture. For H/Be greater than or equal to 14%, the trapping energy is only 1.0-1.2 eV, but explosive release can take place under some circumstances. The implications for Be plasma facing components in tokamaks are discussed.