Chemical reactivity and mobilization of beryllium exposed to steam

Beryllium is used in many fusion reactor designs as either an armor for plasma facing surfaces, or as a neutron multiplier in the blanket. Beryllium used in a water-cooled design poses important safety issues related to the chemical reactivity of beryllium in steam and its toxicity. The fusion safety program at the Idaho National Engineering and Environmental Laboratory has been investigating experimentally the chemical reactivity and mobilization of various forms of beryllium for the past 6 years. In this paper we present a summary of this work, including results from fully dense (irradiated and non-irradiated), plasma-sprayed, and 88% dense beryllium. Assembling this data helps us to assess where further testing is needed. Our data help guide designs such that accident temperatures stay below values necessary to ensure beryllium release limits and hydrogen generation limits are met. (orig.)