[en] The in-reactor creep behavior of 20% cold worked Type 316 stainless steel tubing was investigated at temperatures ranging from 410 to 720⁰C for neutron fluences up to 5 x 10²² n/cm² (E > 0.1 MeV) in the experimental breeder reactor (EBR-II). The irradiation environment was found to either retard or enhance creep rates depending upon the irradiation conditions. When compared to thermal control tests on unirradiated specimens, irradiation enhanced creep rates were observed for temperatures below 620⁰C. Above 620⁰C, however, some specimens exhibited less in-reactor creep than thermal creep of unirradiated specimens. This irradiation hardening was observed for strain rates exceeding 5 x 10^-4% per hour. In-reactor and thermal creep rates were found to be similar at lower strain rates. To fully describe the experimentally observed in-reactor creep behavior with an empirical expression, a commutative equation was developed. The development was based as much as possibe on existing equations for thermal creep and irradiation creep. The thermal creep description is comprised of a slow transient, rapid transient, and a tertiary creep term. The tertiary creep term which becomes important for strain rates greater than 5 x 10^-4% per hour has been modified to predict the irradiation hardening phenomena. Similarly, the irradiation-enhanced contributions to in-reactor creep are comprised of a primary irradiation-enhanced creep term, steady-state irradiation enhanced creep term, and a tertiary irradiation enhanced creep term