Mechanical compression behaviors of single phase Be and binary Be_(12)Ti pebbles

摘要

Beryllium pebbles are planned to be used as a neutron multiplier in the Helium-cooled ceramic breeder (HCCB) tritium breeding blanket module (TBM) of ITER, which is also the primary option of the Chinese TBM program. Advanced neutron multipliers such as Be12Ti beryllide with high stability at elevated temperature are desired for demonstration power plant (DEMO) reactors. Prototypic pebbles 1 mm in diameter of single phase Be and 0.7 mm in diameter of binary Be12Ti beryllide were successfully fabricated by a combination method involving hot isostatic pressing and rotating electrode process. Surface microstructure of Be and Be12Ti pebbles were analyzed by using AFM and SEM. Compression properties of Be and Be12Ti pebbles were evaluated by mechanical compression. Beryllium pebbles displayed high ductility (50% deformation without fracture), which is better than that of beryllide pebbles. One method based on contact mechanics was introduced to evaluate the range of effective modulus and stiffness of Be and Be12Ti from compression load curves in the elastic regime.