Abstract: Disclosed are a nuclear fuel pellet having enhanced thermal conductivity and a method of manufacturing the same, the method including (a) a step of manufacturing a mixture including a nuclear fuel oxide powder and a thermally conductive plate-shaped metal powder; and (b) a step of molding and then heat-treating the thermally conductive plate-shaped metal powder to have an orientation in a horizontal direction in the mixture, thereby forming a pellet.

Abstract: The present invention relates to nuclear fuel pellets and a manufacturing method thereof, and more particularly, to nuclear fuel pellets comprising a trapping material of fission gas and a manufacturing method thereof. A nuclear fuel pellet of the present invention comprises a nuclear fuel; and a trapping material of fission gas, wherein the trapping material of the fission gas includes an oxide containing at least one element selected from the group consisting of silicon (Si), aluminum (Al) and barium (Ba) to exhibit an excellent trapping ability selective and independent for fission gas.

Abstract: Disclosed are a nuclear fuel pellet having enhanced thermal conductivity and a method of manufacturing the same, the method including (a) a step of manufacturing a mixture including a nuclear fuel oxide powder and a thermally conductive plate-shaped metal powder; and (b) a step of molding and then heat-treating the thermally conductive plate-shaped metal powder to have an orientation in a horizontal direction in the mixture, thereby forming a pellet.

Abstract: A method of a nuclear fuel pellet including a thermal conductive metal and a nuclear fuel pellet prepared thereby. The method includes preparing an oxide nuclear fuel granule having about 30%-45% theoretical density, mixing the fuel granule with thermal conductive metal powder, compacting the fuel granule with which the thermal conductive metal powder is mixed to prepare a green pellet, and sintering the green pellet. In the method, the sintering may be performed under a reducing gas atmosphere that is the same as the commercial pellet preparing process. Thus, compatibility compared to existing commercial preparing processes may be superior. Also, since a liquefied oxide formation process and a reducing process are omitted, the distribution uniformity of the metal material within the pellet may be superior. Therefore, the nuclear fuel pellet in which the metal network and fine microstructure are uniformly distributed within the pellet may be prepared.

Abstract: A uranium dioxide nuclear fuel pellet has about 50 to about 400 ?M (with respect to a 3-dimentional size) microcells formed of a ceramic material having a chemical attraction with fission products generated in the nuclear fuel pellet to absorb and trap the fission products, such that the extraction of the fission product may be retrained in a normal operation condition and that the performance of the nuclear fuel may be enhanced by mitigating PCI. In addition, highly radioactive fission products including Cs and I having a large generation amount or a long half-life enough to affect the environments can be trapped in the pellet in an accident condition, without being released outside.

Abstract: Disclosed is a uranium dioxide nuclear fuel pellet, which includes metallic microcell partitions having a high protection capacity for fission products and a high thermal conductivity simultaneously. These metal microcell partitions are arranged in the nuclear fuel pellet to trap fission products. Further disclosed is a method of making the uranium dioxide nuclear fuel pellet. The method includes providing a mixture of uranium dioxide powder and additive powder of Cr-containing compound or Mo-containing compound; compressing the powder mixture to form a green pellet; and then sintering the green pellet under reducing gas environment to form the metallic microcell partitions.

Abstract: A fabrication method of burnable absorber nuclear fuel pellets and burnable absorber nuclear fuel pellets fabricated by the same are provided, in which the fabrication method includes adding boron compound and manganese compound to one or more type of nuclear fuel powders selected from the group consisting of uranium dioxide (UO2), plutonium dioxide (PuO2) and thorium dioxide (ThO2) and mixing the same (step 1), compacting the mixed powder of step 1 into compacts (step 2), and sintering the compacts of step 2 under hydrogen atmosphere (step 3). According to the fabrication method, sintering can be performed under hydrogen atmosphere at a temperature lower than the hydrogen atmosphere sintering that is conventionally applied in the nuclear fuel sintered pellet mass production, by adding sintering additives such as manganese oxide or the like.

Abstract: A method of a nuclear fuel pellet including a thermal conductive metal and a nuclear fuel pellet prepared thereby. The method includes preparing an oxide nuclear fuel granule having about 30%-45% theoretical density, mixing the fuel granule with thermal conductive metal powder, compacting the fuel granule with which the thermal conductive metal powder is mixed to prepare a green pellet, and sintering the green pellet. In the method, the sintering may be performed under a reducing gas atmosphere that is the same as the commercial pellet preparing process. Thus, compatibility compared to existing commercial preparing processes may be superior. Also, since a liquefied oxide formation process and a reducing process are omitted, the distribution uniformity of the metal material within the pellet may be superior. Therefore, the nuclear fuel pellet in which the metal network and fine microstructure are uniformly distributed within the pellet may be prepared.

Abstract: Provided are a method of controlling the compositional gradient and solubility of doped-additives at grain boundaries during sintering of a uranium-based oxide green pellet including the additives, and a method of manufacturing a sintered nuclear fuel pellet having a large grain size using the same. The grain boundary solubility of the doped-additives is maintained at a certain level by stepwise varying of an oxygen partial pressure during isothermal sintering of a uranium-based oxide green pellet including the additives. The method of manufacturing a sintered nuclear fuel pellet having a large grain size includes preparing additive mixed uranium oxide powder, forming an additive mixed uranium oxide green pellet using the mixed powder, heating the green pellet to a sintering temperature in a gas atmosphere having a low oxygen partial pressure, and sintering while a sintering gas atmosphere is changed to stepwise increase an oxygen partial pressure at the isothermal sintering temperature.

Abstract: UO2 nuclear fuel pellets are fabricated by adding additive powder comprising Mn compound and Al compound into UO2 powder.

Abstract: A uranium dioxide nuclear fuel pellet includes metallic microcells having a high protection capacity for fission products and a high thermal conductivity simultaneously arranged in the nuclear fuel pellet to trap fission products, such that extraction of fission products may be restrained in a normal operation condition and that the temperature of a nuclear fuel may be lowered to enhance the performance of the nuclear fuel, only to restrain extraction of radioactive fission products toward the environment in an accident condition to enhance a stability of the nuclear fuel pellet, and a fabricating method thereof.

Abstract: A uranium dioxide nuclear fuel pellet has about 50 to about 400 ?M (with respect to a 3-dimentional size) microcells formed of a ceramic material having a chemical attraction with fission products generated in the nuclear fuel pellet to absorb and trap the fission products, such that the extraction of the fission product may be retrained in a normal operation condition and that the performance of the nuclear fuel may be enhanced by mitigating PCI. In addition, highly radioactive fission products including Cs and I having a large generation amount or a long half-life enough to affect the environments can be trapped in the pellet in an accident condition, without being released outside.

Abstract: A method for fabricating a sintered annular nuclear fuel pellet includes molding nuclear fuel powder or granule, an oxide of a fissile element (M), to fabricate an annular nuclear fuel green body. A rod-like shaped structure is inserted into the annular nuclear fuel green body and sintered in a slight oxidizing gas atmosphere such that the oxide of the fissile element has a balanced O/M ratio higher than a desired O/M ratio (oxygen/fissile element) of a final sintered annular nuclear fuel pellet, while being maintained in a cubic phase. The sintered annular nuclear fuel pellet is then reduced in a reductive gas atmosphere so as to have the desired O/M ratio in the state that the rod-like shaped structure is inserted.

Abstract: A method for fabricating a sintered annular nuclear fuel pellet includes: molding nuclear fuel powder or granules to fabricate an annular nuclear fuel green body; inserting a rod-like shaped structure into the annular nuclear fuel green body; sintering the rod-like shaped structure-inserted annular nuclear fuel green body in a reductive gas atmosphere; and separating the sintered annular nuclear fuel pellet from the rod-like shaped structure.

Abstract: UO2 nuclear fuel pellets are fabricated by adding additive powder comprising Mn compound and Al compound into UO2 powder.

Abstract: There is provided a method of producing U3O8 powder having large surface area and small particle size by oxidizing defective UO2 pellets and manufacturing nuclear fuel pellets which are stable in a pore structure and high in density through the use of a mixture comprising UO2 powder and U3O8 powder. The method includes producing an U308 powder having a surface area of at least 1 m2/g by oxidizing defective UO2 pellets at a temperature of 300 to 370° C. in such a way that a maximum weight increase rate per 1 g of the UO2 pellets is up to 0.06 wt %/min; producing a mixed powder by mixing the U3O8 powder with an UO2 powder 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° C. In addition, a small amount of an Al-compound may be added to the oxidized U3O8 powder before the U3O8 powder is mixed with the UO2 powder.

Abstract: 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.

Abstract: Provided are a method of controlling the compositional gradient and solubility of doped-additives at grain boundaries during sintering of a uranium-based oxide green pellet including the additives, and a method of manufacturing a sintered nuclear fuel pellet having a large grain size using the same. The grain boundary solubility of the doped-additives is maintained at a certain level by stepwise varying of an oxygen partial pressure during isothermal sintering of a uranium-based oxide green pellet including the additives. The method of manufacturing a sintered nuclear fuel pellet having a large grain size includes preparing additive mixed uranium oxide powder, forming an additive mixed uranium oxide green pellet using the mixed powder, heating the green pellet to a sintering temperature in a gas atmosphere having a low oxygen partial pressure, and sintering while a sintering gas atmosphere is changed to stepwise increase an oxygen partial pressure at the isothermal sintering temperature.

Abstract: A method for fabricating a sintered annular nuclear fuel pellet includes: molding nuclear fuel powder or granules to fabricate an annular nuclear fuel green body; inserting a rod-like shaped structure into the annular nuclear fuel green body; sintering the rod-like shaped structure-inserted annular nuclear fuel green body in a reductive gas atmosphere; and separating the sintered annular nuclear fuel pellet from the rod-like shaped structure.

Abstract: A method for fabricating a sintered annular nuclear fuel pellet includes molding nuclear fuel powder or granule, an oxide of a fissile element (M), to fabricate an annular nuclear fuel green body. A rod-like shaped structure is inserted into the annular nuclear fuel green body and sintered in a slight oxidizing gas atmosphere such that the oxide of the fissile element has a balanced O/M ratio higher than a desired O/M ratio (oxygen/fissile element) of a final sintered annular nuclear fuel pellet, while being maintained in a cubic phase. The sintered annular nuclear fuel pellet is then reduced in a reductive gas atmosphere so as to have the desired O/M ratio in the state that the rod-like shaped structure is inserted.