0 Steam Chemical R E 2 4 C " Y of Plasmas - Sprayed Beryllium

Plasma-spraying with the potential for in-situ repair makes beryllium a primary candidate for plasma facing and structural components in experimental magnetic h i o n machines. Deposits with good thermal conductivity and resistance to thermal cycling have been produced with low pressure plasma-spraying (LPPS). A concern during a potential accident with steam ingress is the amount of hydrogen produced by the reactions of steam with hot components. In this study we measure the reaction rates of various deposits produced by LPPS with steam from 350°C to above 1000°C. We correlate these reaction rates with measurements of density, open porosity and I3ET surface areas. We find the reactivity to be largely depndent upon effective surface area. Promising results were obtained below 600°C fiom a 94% theoretical dense ('I'D) deposit with a BET specific surface area of 0.085 m*/g Although reaction rates were higher than those for dense consolidated beryllium they were substantially lower, i.e.. about two orders of magnitude, than those obtained from previously tested lower density plasma-sprayed deposits.