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.

Abstract: A polymer composition includes a rubber modified vinyl resin, a polyphenylene ether resin, a cyclic alkyl phosphate compound, and an aromatic phosphate ester. In some embodiments, the cyclic alkyl phosphate compound is able to impart good flame retardancy to the composition and thermal resistance to the polymer composition.

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: A polymer composition includes a rubber modified aromatic vinyl resin and a cyclic alkyl phosphate compound. In some embodiments, the cyclic alkyl phosphate compound is able to impart good flame retardancy to the composition, while maintaining a good balance of the other physical and mechanical properties of the resin including Vicat Softening Temperature and impact strength.

Abstract: A polymer composition includes a rubber modified vinyl resin, a cyclic alkyl phosphate compound, and an aromatic phosphate ester. Some embodiments may additionally comprises a polyphenylene ether resin. In some embodiments, the compositions have good flame retardancy, color stability, impact resistance, and thermal stability.

Abstract: The thermoplastic ABS resin composition according to the present invention comprises (a) 2 to 25 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.05 ?m to less than 0.18 ?m; (b) 2 to 25 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.18 ?m to less than 0.4 ?m; (c) 2 to 18 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.4 ?m to less than 4 ?m; (d) 10 to 70 parts by weight of a branched vinyl cyanide-vinyl aromatic copolymer; and (e) 1 to 60 parts by weight of a long-chain linear vinyl cyanide-vinyl aromatic copolymer.

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 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 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: The flameproof resin composition according to the present invention (A) 100 parts by weight of a rubber modified polystyrene resin containing (a1) 20 to 100% by weight of graft copolymer prepared by graft-polymerizing 5 to 65% by weight of a rubber polymer, 30 to 95% by weight of an aromatic vinyl monomer, 0 to 20% by weight of a monomer copolymerizable with said aromatic vinyl monomer and 0 to 15% by weight of a monomer for providing good processability and heat resistance; and (a2) 0 to 80% by weight of copolymer prepared by polymerizing 60 to 90% by weight of an aromatic vinyl monomer, 10 to 40% by weight of a monomer copolymerizable with said aromatic vinyl monomer and 0 to 30% by weight of a monomer for providing good processability and heat resistance; and (B) 15 to 40 parts by weight of a ring-shaped alkyl phosphonic acid compound.

Abstract: The present invention relates to a flame retardant thermoplastic resin composition that contains a phenol resin derivative having good char formability, regardless of the base resin. A flame retardant thermoplastic resin composition according to the present invention comprises (A) 100 parts by weight of a thermoplastic resin as a base resin, (B) about 0.1˜100 parts by weight of a phenol resin derivative, and (C) about 0.1˜50 parts by weight of a phosphorous compound or a mixture of phosphorous compounds.

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.

Abstract: The thermoplastic ABS resin composition according to the present invention comprises (a) 2 to 25 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.05 ?m to less than 0.18 ?m; (b) 2 to 25 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.18 ?m to less than 0.4 ?m; (c) 2 to 18 parts by weight of a graft copolymer particle containing rubbers having a volume average particle diameter range from 0.4 ?m to less than 4 ?m; (d) 10 to 70 parts by weight of a branched vinyl cyanide-vinyl aromatic copolymer; and (e) 1 to 60 parts by weight of a long-chain linear vinyl cyanide-vinyl aromatic copolymer.

Abstract: Disclosed herein is a styrenic resin composition comprising (A) about 15 to about 80 parts by weight of a styrenic resin, (B) about 15 to about 80 parts by weight of a polyphenylene ether resin, and (C) about 0.1 to about 25 parts by weight of a phosphoric compound comprising (c1) about 1 to about 30% by weight of an alkyl phosphinic metal salt and (c2) about 70 to about 99% by weight of an aromatic phosphate ester, per 100 parts by weight of a base resin comprising (A) and (B).

Abstract: An apparatus for forming a thin film on a substrate includes a chamber having a gas inlet, an upper electrode in the chamber, the upper electrode having a plurality of nozzles, a lower electrode in the chamber for supporting the substrate thereon, the lower electrode being spaced apart from the upper electrode, and a selective injection plate above the upper electrode, the selective injection plate including a selective injection valve for selectively concentrating a gas supplied through the gas inlet onto a portion of the upper electrode.

Abstract: A thermoplastic flame retardant resin composition according to the present invention comprises: (A) about 40˜95 parts by weight of a styrenic resin; (B) about 5˜60 parts by weight of a polyphenylene ether, (C) about 0.1˜40 parts by weight of a rubber modified polystyrene resin containing about 40˜65% by weight of a rubber and about 0.1˜8% by weight of acrylonitrile based on 100 parts by weight of the sum of (A) and (B); and (D) about 5 to 30 parts by weight of an aromatic phosphoric acid ester compound based on 100 parts by weight of the sum of (A) and (B).

Abstract: The present invention relates to a flame retardant thermoplastic resin composition that contains a polyphenylene ether resin and a phenol resin derivative, both of them having good char formability, regardless of the base resin. A flame retardant thermoplastic resin composition according to the present invention comprises (A) 100 parts by weight of a thermoplastic resin as a base resin, (B) about 0.1˜100 parts by weight of polyphenylene ether, (C) about 0.1˜100 parts by weight of a phenol resin derivative, and (D) about 0.1˜50 parts by weight of a phosphorous compound or a mixture of phosphorous compounds. The thermoplastic resin composition may contain up to 5.0 parts by weight of an anti-dripping agent based on 100 parts by weight of the base resin.