Results of several uniaxial in-reactor creep tests, carried out in a temperature range of 553 to 623 K on Zircaloy-2 cold-worked specimens in fast flux (E > 1 MeV) from 1.2 × 1017 to 1.1 × 1018 n·m−2 · s and in a stress range from 98 to 157 MPa, are presented. The effects of instantaneous flux and applied tensile stress are investigated, and the available data correlated by functional relationship. The effect of the temperature on the creep rate in the presence and absence of flux is also investigated and discussed.