Patent ID: 6125161
Filing Date: 2000-09-26
Classification: G21C,Y02E

Abstract:
A method for making Zr alloy nuclear reactor fuel cladding, the method comprising: performing hot forging, solution heat treatment, hot extruding, and repeated cycles of annealing and cold rolling, ending in a final cold rolling, of a Zr alloy comprising, by weight, 0.2 to 1.7% Sn, 0.18 to 0.6% Fe, 0.07 to 0.4% Cr and 0.05 to 1.0% Nb, with a remainder being Zr and incidental impurities, and an incidental nitrogen impurity content being 60 ppm or less, and then performing final stress relief annealing thereon; whereinsaid annealing is performed in a range of temperatures between about 550.degree. C. and about 850.degree. C. for a period of time between about 1 hour and about 4 hours such that an accumulated annealing parameter .SIGMA.Ai represented by.SIGMA.Ai=.SIGMA.ti.multidot.exp(-40,000/Ti) satisfies relationships as follow:-20.ltoreq.log.SIGMA.Ai.ltoreq.-15, and-18-10.multidot.X.sub.Nb .ltoreq.log.SIGMA.Ai.ltoreq.-15-3.75.multidot.(X.sub.Nb -0.2),wherein Ai represents an annealing parameter for an i-th annealing,ti represents annealing time (hours) for the i-th annealing,Ti represents annealing temperature (K) for the i-th annealing, andX.sub.Nb represents Nb concentration (wt %).