抄録
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 603693 K and the hoop stress of 49314 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:
Saturated primary creep strain:
Steady-state creep rate:
The apparent activation energy of the steady-state creep, which is 2.72 t× 105 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.
