FUEL ELEMENT, ITS MANUFACTURING METHOD AND DEVICE Russian patent published in 2003 - IPC

FIELD: fuel elements for nuclear reactors. SUBSTANCE: fuel element has can filled with nuclear fuel. One seam is made by resistance butt welding with plug being deepened. Fuel element diameter in vicinity of weld obtained is not over original diameter of can. Changed structure area is located both in can and in plug. Ratio of maximal radial width of this plug area in any section of weld to half the original diameter of plug is maximum 1/3. Proposed method for plug manufacture includes manufacture of plug with outer diameter greater than inner diameter of can and smaller than its outer diameter; can deepening and locking in current contact jaw; compression of can-and-plug assembly, and heating of parts being welded by electric current distributed over can section in vicinity of welding point at the same time affording heat transfer from outer surface of can to outer buttend part of plug. Ratio of plug diameter to diameter of lower end cap is 0.95 1.1. In the course of locking and current supply locked end of can is set on cone in flexible area of strain with can primarily heated over edges of welding area by welding current. Welding is conducted at rate of rise of current between 0.4 and 5 kA/ms. Proposed device for fuel element manufacture has annular split current contact jaw incorporating high-resistance section in welding contact forming area. Resistance of this section is always higher that that of fuel element can at welding point. EFFECT: enhanced reliability and sealing stability, as well as simplified design of device. 5 cl, 3 dwg