Pressure tubes for CANada Deuterium Uranium Pressurized Heavy Water reactors are made from Zr-2.5Nb by extruding preheated hollow billets into tubes that are cold-worked 30 percent to size. The fabrication process produces fine elongated α-grains with a high dislocation density which makes a large contribution to the tensile strength of the tubes but increases in-reactor creep and growth rates.

The alloy Excel (Zr-3.5Sn-0.8Mo-0.8Nb) is stronger and more creep resistant than Zr-2.5Nb and is being developed as a pressure tube material. Tubes have been fabricated that are as strong as the Zr-2.5Nb tubes but they have more equiaxed α-grains with much lower dislocation densities. The tubes corrode faster than the Zr-2.5Nb tubes and will require 0.1 mm more corrosion allowance on the 4.1-mm-thick walls. However, their in-service axial elongation and diametral expansion due to irradiation creep and growth will be 70 percent less than the Zr-2.5Nb tubes.