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Nuclear irradiation creep, often simply referred to as irradiation creep, is a special type of plastic deformation that occurs in materials under the combined effect of stress and nuclear radiation. It is one of the primary damage mechanisms for structural materials in nuclear reactors, and was officially recognized as a term in materials science and technology in 2011. I. Core classification: Irradiation-enhanced creep: The point defects generated by irradiation significantly increase the dislocation climb rate, enabling dislocations that are otherwise hindered by second-phase particles to move more easily, thereby accelerating the creep process of the material. Irradiation-induced creep: Under stress, dislocations of different orientations within a material preferentially absorb the point defects generated by irradiation, leading to anisotropic deformation; creep can occur even in low-temperature environments where significant thermal creep does not take place. II. Key influencing factors: The occurrence of this phenomenon is directly related to temperature, stress levels, and neutron irradiation flux/dose. There are significant differences in the resistance to irradiation-induced creep among different materials: ferritic/martensitic steels are less affected by irradiation, resulting in a smaller decrease in allowable stress ； The allowable stress of austenitic stainless steels (such as 316 steel) in an irradiated environment decreases significantly. III. Engineering application value: It is a key factor in the structural design of reactors, and is widely used for assessing the service life of components in pressurized water reactors, fast neutron breeder reactors, and fusion reactors (such as China’s CFETR). It applies to critical components such as fuel cladding, core graphite elements, control rods, and the first wall of fusion reactors, and is directly related to the long-term operational safety of reactors.