Abstract: A sample of the pressure tube of a CANDU type of nuclear reactor is obtained for deuterium analyses without removing the pressure tube from the reactor. The preferred sampling tool comprises two cutters and means for capturing the removed material, wherein one cutter removes the surface oxide layer, and the second cutter removes a sample for analysis. The cutters and cutting operation are designed to avoid damaging the integrity of the pressure tube to allow it to remain in service. In the preferred embodiment, the sampling tool performs the surface and sample removal operation with the fueling equipment with simple linear movement.

Abstract: A process for fabricating tubes from a quaternary 3.5% Sn, 1% Mo, 1% Nb balance Zr alloy by hot extrusion, cold working and heat treatment so that the tubes have small grains that have low dislocation densities. The tubes are superior to the standard cold worked Zr-2.5 wt % Nb tubes because during service in CANDU-PHW reactors they (a) have lower axial elongation and diametral expansion and (b) the hydrides are less susceptible to reorientation from the circumferential-axial plane into the radial-axial plane.

Abstract: Tubes for use in nuclear reactors fabricated from a quaternary alloy comprising 2.5-4.0 wt% Sn, 0.5-1.5 wt% Mo, 0.5-1.5 wt% Nb, balance essentially Zr. The tubes are fabricated by a process of hot extrusion, heat treatment, cold working to size and age hardening, so as to produce a microstructure comprising elongated .alpha. grains with an acicular transformed .beta. grain boundary phase.