Steam-chemical reactivity for irradiated beryllium

This paper reports experimental results concerning the influence of neutron irradiation effects and annealing on the chemical reactivity of beryllium exposed to steam. The work entailed: (1) measurements of swelling, porosity and specific surface area for irradiated Be annealed at temperatures ranging from 700 deg C to 1200 deg C and (2) measurements of hydrogen generation rates for unirradiated Be, irradiated Be and irradiated-annealed Be exposed to steam at elevated temperatures. For irradiated Be, volumetric swelling increased from 14% at a 700 deg C anneal to about 56% at a 1200 deg C anneal. Gas-release measurements during annealing indicated the development of a surface-connected porosity network. Specific surface areas for irradiated-annealed Be increased with the anneal temperature. Steam-chemical reactivity was similar for irradiated and unirradiated Be at temperatures between 450 deg C and 600 deg C. For irradiated Be exposed to steam at 700 deg C, the reactivity accelerated rapidly and the specimen experienced a temperature excursion. Irradiated-annealed Be showed enhanced chemical reactivity related to its higher specific surface area.