Neutron irradiation effects on carbon and graphite cloths and fibers

A series of cloth and fiber samples were irradiated to fluences of 3.5, 7.3, and 10 x 1021 cm-2 at 4700C. Dimensional changes of the fibers in the radial direction ranged from -19% to +33% and in the axial direction from -18% to -27%, roughly ten times greater than dimensional changes found for typical nuclear graphites. Despite these large dimensional changes, all but one of the 2-dimensional cloths remained essentially unchanged in overall physical appearance. The 3-dimensional cloths, on the other hand, deteriorated apparently because these types of weaves were less able to accommodate the large axial fiber shrinkages