NUCLEAR REACTOR FUEL ELEMENT Russian patent published in 2011 - IPC G21C3/00 

FIELD: power engineering.

SUBSTANCE: nuclear reactor fuel element comprises a cylindrical metal shell, which contains nuclear fuel in the form of a column of uranium dioxide pellets, a fixing element, a lower and upper plugs, along with the coolant flow in the reactor core. Besides, the fixing element is arranged in the form of a twisted spring, in which the support turns at one side of the spring rests against the fuel column of pellets, and at the other side of the spring - against the internal end of the upper plug, which comprises a support turn alignment element. The spring has a cylindrical working part, turns of which are arranged with identical diametre, and a shaped part, turns of which are arranged with alternating diametre. The support turn of the spring shaped part of the fixing element at the side of the upper plug has external diametre, which is less than the diametre of the zone with modified structure, formed at the internal end of the upper plug when the shell is sealed, the length of the spring shaped part in previously compressed condition is more than the zone with modified structure formed along the length of the wall as a result of sealing, and the alignment element at the end of the upper plug is made in the form of a conical ledge with the base diametre that is less than the diametre of the zone with the modified structure by value of the diametre of the wire, from which the spring is made. The turns of the fixing element shaped part are arranged in pressed condition. The alignment element of the upper plug may be arranged as a conical groove at the internal end of the plug, has the base diametre of 0.75-0.9 of the fuel element shell internal diametre and depth of 0.1-0.2 of the length of plug and shell welded joint zone.

EFFECT: increased reliability of fuel element operation with reduction of costs for its production.

2 cl, 10 dwg