SEDL / STP / STP824-EB / STP34476S

In-Reactor Creep of Zr-2.5Nb

Causey, AR
Atomic Energy of Canada Ltd., Chalk River Nuclear Laboratories, Chalk River, Ont.

Holt, RA
Atomic Energy of Canada Ltd., Chalk River Nuclear Laboratories, Chalk River, Ont.

MacEwen, SR
Atomic Energy of Canada Ltd., Chalk River Nuclear Laboratories, Chalk River, Ont.

Pages: 20    Published: Jan 1984

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Abstract

The anisotropy of irradiation creep of Zr-2.5Nb alloy tubes at 570 K has been investigated using creep of helical springs and stress relaxation of twisted rods and bent beams. These tests measure creep rate directly since strains associated with irradiation growth are absent. Creep rates from these tests and from results on creep of pressurized tubes reported in the literature can be correlated through consideration of the crystallographic texture, slip systems, and dislocation density of the Zr-2.5Nb tubing. A creep model based on glide of 1∕3⟨11¯20⟩ type dislocations on prismatic planes in combination with secondary glide of 1∕3⟨11¯22⟩ dislocations on {10¯11} pyramidal planes provides a consistent correlation. The creep rate is only slightly dependent on dislocation density as measured by X-ray diffraction.