With doses simulating those received by spent nuclear fuel (SNF) facilities, gamma-ray (γ-ray) irradiation experiments were conducted on hexagonal zirconium. γ-ray irradiation–induced crystalline defects were observed in the hexagonal zirconium and characterized. Monte Carlo calculations combined with Transmission Electron Microscopy characterizations revealed that the energy of primary knock-on atoms could reach the threshold energy (Ed) of zirconium atoms and result in dislocation loops within the α-zirconium grains. The influence of γ dose on dislocation loop...