Patent Number: 056205368
Section: description

An ingot of the inner component is manufactured (1). The inner component consists of zirconium with 0.25% Sn, 310 ppm Fe and 430 ppm O as well as impurity quantities normally occurring in reactor-grade zirconium. Thereafter, the ingot is preheated (2) and forged (3). These steps can be repeated by preliminary forging and finally forging the ingot. The ingot is preheated to a temperature of 820.degree. C. for 8 hours (2) and is forged (3), whereupon an additional heating to 800.degree. C. (2) and a final forging (3) are carried out. After forging, the billet is rolled down (4) and extruded at a temperature of about 670.degree. C. (5). Thereafter, the billet is annealed at 650.degree. C. for 5 hours (6). The outer component is manufactured conventionally by forging and is beta-quenched before extrusion (7, 8, 9, 10, 11). The inner component is joined to the outer component in conventional manner and the composite body is extruded (12) at a temperature of about 670.degree. C. Thereafter, the tube blank is rolled in three stages into the final dimension with intermediate annealings at 570.degree. C. for 1 hour (13, 14). After the last rolling, the tube is finally annealed at 570.degree. C. for 1.5 hours (15). The cladding tubes are filled with fuel pellets and sealed, whereupon they are assembled into bundles forming nuclear fuel elements intended for light-water reactors.