LOW IN REACTOR CREEP ZR-BASE ALLOY TUBES

摘要

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 densitics. The tubes are superior to the standard cold worked Zr-2.5wt% 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.