Radiation effects in beryllium as produced by fast neutrons and resulting in dimensional changes are reviewed. It is found that helium bubble swelling is the predominant mechanism; however, because of the intrinsic anisotropy of the dislocation structure, bubble swelling is expected to be anisotropic, accompanied by radiation-induced growth. The anisotropy of swelling and plastic deformation at the microscopic level of crystal grains eventually results in microcracking, and the total inelastic deformation should therefore not exceed about 1%.