Korea Atomic Energy Research Institute

Korea Hydro Nuclear Power Co., Ltd.

Keon Sik Kim

Jong Hun Kim

Kun Woo Song

Jae Ho Yang

Ki Won Kang

Young Woo Rhee

Youn Ho Jung

Dong Seok Kim

Dong Joo Kim

Sang Chae Jeon

Ji Hae Yoon

UOnuclear fuel pellets are fabricated by adding additive powder comprising Mn compound and Al compound into UOpowder.

Uranium dioxide nuclear fuel containing Mn and Al as additives and method of fabricating the same

There is provided a method of producing UOpowder having large surface area and small particle size by oxidizing defective UOpellets and manufacturing nuclear fuel pellets which are stable in a pore structure and high in density through the use of a mixture comprising UOpowder and UOpowder. The method includes producing an U308 powder having a surface area of at least 1 m/g by oxidizing defective UOpellets at a temperature of 300 to 370&#xb0; C. in such a way that a maximum weight increase rate per 1 g of the UOpellets is up to 0.06 wt %/min; producing a mixed powder by mixing the UOpowder with an UOpowder by 2 to 15 wt %; producing a compact by compression molding the mixed powder; and sintering the compact in a reducing gas atmosphere at a temperature of 1600 to 1800&#xb0; C. In addition, a small amount of an Al-compound may be added to the oxidized UOpowder before the UOpowder is mixed with the UOpowder. The additive such as Al is mixed with the UOpowder and then mixed with the UOpowder to produce the pellets by a conventional production method. This ensures a stable pore structure, high density and a considerable increase in a crystal grain size.

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A method for manufacturing an annular nuclear fuel pellet is provided. In the method, an annular nuclear fuel green compact whose lateral cross-section is a trapezoid is prepared. The thickness of the annular nuclear fuel green compact reduces along one direction of the central axis, and a green density of the nuclear fuel green compact increases along one direction of the central axis. The annular nuclear fuel green compact is sintered under a reducing gas atmosphere so that the annular nuclear fuel pellet is obtained. According to this method, the annular pellet which has uniform inner and outer diameters and small diametric tolerances along the pellet height is fabricated without grinding the pellet surfaces.

Method for manufacturing sintered annular nuclear fuel pellet without surface grinding

A method for fabricating a sintered duplex nuclear fuel pellet includes the steps of: preparing a first powder composed of a material selected from the group consisting of UOand UO&#x2014;ErO, and a second powder composed of UO&#x2014;GdOand a sintering additive; producing a duplex compact consisting of an annular outer portion composed of the first powder and a cylindrical inner portion composed of the second powder; and sintering the duplex compact under a reducing gas atmosphere, wherein the sintering additive contains manganese of 0.001% to 2% by weight based on the total weight of the cylindrical inner portion.

Fabrication method of sintered duplex nuclear fuel pellet

The present invention relates to a nuclear fuel body comprising tungsten network and a method for manufacturing the same, more particularly, a nuclear fuel body in which tungsten network is continuously formed over the entire or some parts of a sintered body and a method for manufacturing the same. The sintered body in the nuclear fuel body of the present invention contains tungsten network having excellent heat conductivity, leading to the enhancement of heat conductivity of the nuclear fuel sintered body itself with decreasing the temperature of the nuclear fuel, so that it can contribute to the improvement in safety and performance of nuclear fuel.

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Daejeon, South Korea

Keon Sik Kim