Top nozzle for nuclear fuel assembly having spring insert hole improved in fastening stability and method of manufacturing the same

Abstract

A top nozzle for a nuclear fuel assembly and a method of manufacturing the top nozzle are provided. The top nozzle can include a coupling plate, a perimeter wall and a hold-down spring unit. The coupling plate can be coupled to a guide thimble of the nuclear fuel assembly. The perimeter wall can protrude upwards from the perimeter of the coupling plate. A spring clamp can be provided on the upper surface of the perimeter wall. The hold-down spring unit can be mounted to the upper surface of the perimeter wall in such a way to couple a corresponding end of the hold-down spring unit to the spring clamp. A fastening pin hole can be vertically formed through an upper surface of the spring clamp. A spring insert hole into which the hold-down spring unit can be inserted and formed by electro-discharge machining in an insert direction of the hold-down spring.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present application claims priority benefits under 35 U.S.C. §1.119 to KR10-2010-0006469 filed Jan. 25, 2010.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a top nozzle for a nuclear fuel assembly having a spring insert hole.[0004]2. Description of the Related Art[0005]As is well known to those skilled in the art, a nuclear reactor is a device in which a fission chain reaction of fissionable materials is controlled for the purpose of generating heat, producing radioactive isotopes and plutonium, or forming a radiation field.[0006]Generally, in light-water reactor nuclear power plants, enriched uranium, which is increased in the ratio of uranium-235 to 2% through 5%, is used. To process enriched uranium into nuclear fuel to be used in nuclear reactors, a forming process, by which uranium is formed into a cylindrical pellet having a weight of about 5 g, is conducted. Several hundreds of ...

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