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

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: According to one embodiment, a method of recording a digital stream on a recording medium, includes checking an existence of entry point information in a received digital transport stream, the entry point information associated with entry points in the digital transport stream, the digital transport stream comprising a plurality of data packets; grouping received data packets into one or more data object units based on the entry point information as a result of the checking step, and grouping one or more data object units into one data object; and recording the received data packets on the basis of the data object on the recoding medium.

Abstract: A recording medium, method and apparatus for providing management information are provided. According to an embodiment, the method includes grouping data of a digital stream into a plurality of object units, and grouping one or more object units into an object; and creating management information for accessing the data, the management information including map information and indication information, wherein the map information includes an object unit index table associated with the object units, and wherein the indication information indicates whether the data of the digital stream are grouped into the object units on a basis of a predetermined time period or an entry point information included in the digital stream.

Abstract: A recording medium, method and apparatus for providing management information are provided. According to an embodiment, the method includes grouping data of a digital stream into a plurality of object units, and grouping one or more object units into an object; and creating management information for accessing the data, the management information including map information and indication information, wherein the map information includes an object unit index table associated with the object units, and the object unit index table includes object unit information associated with the object units, and wherein the indication information indicates whether the data of the digital stream are grouped into the object units on a basis of a predetermined time period or an entry point information included in the digital stream.

Abstract: According to an embodiment, a method of recording a digital stream on a recording medium, includes determining one of at least two recording modes to record a transmitted digital stream, wherein a first recording mode is to record data based on entry point information present in the digital stream and a second recording mode is to record data on a basis of a predetermined time; and recording the digital stream based on the determined recording mode, and recording a mode information indicating the determined recording mode.

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: In a method of producing large-grained nuclear fuel pellet, Cr-compound contained in an uranium oxide green pellet is reduced to Cr phase at 1,470° C. or below and maintained to the Cr phase, and the uranium oxide green pellet containing the Cr-compound is then sintered at 1,650° C.-1,800° C. in a gas atmosphere of oxygen potential at which Cr element in the uranium oxide green pellet becomes liquid phase.

Abstract: A method and apparatus are provided for creating and recording management information for digital data streams, and for reproducing data using the management information. According to an embodiment, the method for recording a digital data stream being received, comprising: (a) recording received stream units of a digital data stream along with their arrival time references representing the arrival times of the received stream units on a recording medium; (b) grouping the received stream units into stream object units of a predetermined size, such that the maximum search time for a stream object unit is almost uniform among the recorded stream object units; and (c) creating and recording reproduction management information regarding the stream object units.

Abstract: A method and apparatus for recording time information for received digital data streams are provided. The method includes recording first time information and second time information on a recording medium. The first time information is part of management data for managing presentation data and the second time information is time information of the presentation data. The format of the first time information coincides with the format of the second time information.

Abstract: A high-frequency inductive heating apparatus of ceramic material, whereby the nonconductive ceramic specimen in which induced current is not generated at room temperature is rapidly heated in a preheating housing, and a pressure-less sintering method using the same, are disclosed. The high-frequency inductive heating apparatus includes a preheating housing placed in a chamber to preheat a ceramic material; an induction coil installed around the preheating housing for supplying induced current so that the preheating housing is heated; and a high-frequency current generator for supplying high-frequency current to the induction coil. According to the present invention, inductive heating is made possible of nonconductive ceramic material for which inductive heating has thus far been impossible because induced current is not generated at room temperature, so that rapid heating by the self-heating of the specimen of ceramic material is possible.

Abstract: A method and apparatus are provided for creating and recording management information for digital data streams, and for reproducing data using the management information. The method for reproducing data from a recording medium includes receiving an access time for accessing data from the recording medium, searching for a target entry point based on the access time by using access time entries, and searching for a target object unit by using the target entry point and object unit entries. The access time entries and the object unit entries are management information stored on the recording medium.

Abstract: A recording medium with the increased recording efficiency is provided. Depending upon the size of the remaining area of a sector, a transport stream unit is recorded across two sectors with the result that sectors contain no null data. If the size of the remaining area of the last sector of a stream object unit is less than the size of a transport stream unit, the remaining area is padded with null data.

Abstract: In a method for creating and recording management information for searching recorded digital data streams when a digital data stream is recorded on a recording medium, index information for pointing to the location of the time information corresponding to the first stream object unit of each stream object on a time information table is created and recorded. When reproducing or searching the recorded digital data stream, a stream object is found using the time information of stream objects and the recording location corresponding to a requested search time is found using the index information.

Abstract: A recording medium with the increased recording efficiency is provided. Depending upon the size of the remaining area of a sector, a transport stream unit is recorded across two sectors with the result that sectors contain no null data. If the size of the remaining area of the last sector of a stream object unit is less than the size of a transport stream unit, the remaining area is padded with null data.

Abstract: 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 UO2 and UO2—Er2O3, and a second powder composed of UO2—Gd2O3 and 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.

Abstract: A recording medium, apparatus and method for recording a digital data stream on the recording medium are discussed. The method according to an embodiment includes recording the digital data stream by dividing the digital data stream into stream objects; recording common information for the stream objects; and recording stream time map information in a stream information file of the recording medium, the stream time map information including a time mapping list having time search information for searching the stream objects.

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? 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?. 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.