Irradiation creep due to point defect absorption at dislocations

The stress induced preferential absorption (SIPA) mechanism of irradiation creep is briefly reviewed. Its origin is explained in terms of the first-order size effect interaction and the induced interaction between the intrinsic point defects and the dislocations. These two interactions combine in a body under uniaxial stress to ensure that preferential absorption of interstitials will occur at those edge dislocations oriented with their extra planes normal to the stress axis and vice-versa for the vacancies. A simplified rate theory argument is used to deduce the magnitude and microstructural dependence of the resulting creep strain. It is shown that the calculated creep rate is linear in applied stress and irradiating flux and is fairly independent of temperature. (author)