Thermomechanical behaviour of ceramic breeder and beryllium pebble beds

In order to describe the interaction between ceramic breeder and beryllium pebble beds and the structural material in ceramic breeder blankets, the characteristic properties of these pebble beds in the relevant temperature and pressure ranges must be known. Uniaxial compression tests with Li4SiO4 pebble beds were performed in temperatures between ambient and 900°C and pressures up to 8 MPa. Corresponding experiments with a smaller parameter variation were carried out with Li2TiO3, Li2ZrO3, and Li2O pebble beds. Empirical correlations for the moduli of deformation are presented for the different materials and first relationships for thermal creep of Li4SiO4 pebble beds are given. Using a different test facility, uniaxial tests were carried out with monosized and binary beryllium pebble beds in a temperature range between ambient and 480°C and pressures up to 8 MPa. Again, relationships for the deformation modulus are presented.