Thermal creep of zircaloy-4 cladding under internal pressure

Abstract

Creep characteristics of Zircaloy-4 stress-releaved cladding under internal pressure were studied. Creep tests were conducted under 21 conditions chosen from the temperature range of 603-693 K and the hoop stress of 49-314 MPa. The maximum accumulated test period was 3,000 h. Diametral creep data were analyzed by separating the primary (transient) and the secondary (steady-state) creep, based on Dorn’s quasitheretical model, and the following equations were derived: Total creep strain: [formula present] Saturated primary creep strain: [formula present] Steady-state creep rate: [formula present]. The apparent activation energy of the steady-state creep, which is 2.72 x 10s J/mol, is in good agreement with these of self-diffusion of Zr in Zr-Sn alloys and suggests the self-diffusion is the control mechanism. © 1987 Taylor & Francis Group, LLC.