Abstract: The present disclosure relates to a pellet containing an oxide additive to improve a nuclear-fission-gas-adsorption ability of a uranium-dioxide pellet used as nuclear fuel and increase the grain size thereof, and to a method of manufacturing the same. A La2O3—Al2O3—SiO2 sintering additive is added to uranium dioxide so that mass movement is accelerated due to the liquid phase generated during sintering of the uranium-dioxide pellet, which promotes the growth of grains thereof. Further, since less volatilization occurs during sintering due to the low vapor pressure of the liquid phase, efficient additive performance is exhibited, so the liquid phase surrounding the grain boundary effectively adsorbs cesium, which is a nuclear fission gas.

Abstract: Proposed is a nuclear fuel pellet manufactured with UO2 powder and being in a cylindrical shape, the nuclear fuel pellet including: a dish (10) provided in a shape of a spherical groove having a predetermined curvature and a diameter of 4.8 to 5.2 mm at a center of each of top and bottom surfaces of the nuclear fuel pellet; a shoulder (20) provided in an annular plane along a rim of the dish (10); a first chamfer (310) provided along a rim of the shoulder (20) while being adjacent to the shoulder (20); and a second chamfer (320) provided along a rim of the first chamfer (310), wherein a width (SW) of the shoulder (20) is 0.4565 mm to 0.6565 mm, an angle between the first chamfer (310) and a horizontal plane is 2.0°, and an angle between the second chamfer (320) and the horizontal plane is 18.0°.

Abstract: Provided is a nuclear-fuel sintered pellet based on oxide in which a plate-type fine precipitate material in a base of a sintered pellet of uranium dioxide, used as nuclear fuel in nuclear power plants, is uniformly dispersed in a matrix of uranium dioxide fuel thereof so as to form a donut-shaped precipitate cluster, and to a method of manufacturing the same. The plate-type fine precipitate material is uniformly precipitated in a tissue thereof or forms a donut-shaped precipitate cluster having a two-dimensional structure through dispersion to improve thermal and physical performance of the nuclear-fuel sintered pellet of uranium dioxide, whereby the creep deformation rate and thermal conductivity of the sintered pellet are improved. The nuclear-fuel sintered pellet based on oxide can reduce the Pellet-Clad Interaction (PCI) failure and the core temperature of nuclear fuel when an accident occurs, thereby significantly improving the safety of a nuclear reactor.

Abstract: Proposed are nuclear fuel pellets showing high oxidation resistance in a steam atmosphere and a method for manufacturing same. The method includes: preparing a powder mixture by mixing a sintering additive powder including Cr2O3, MnO, and SiO2 with a uranium dioxide powder; forming a molded body by subjecting the powder mixture to compression molding; and sintering the molded body in a weak oxidative atmosphere in which an oxygen potential is ?581.9 kJ/mol to ?218.2 kJ/mol. The nuclear fuel pellets contain 0.05% to 0.16% by weight of the sintering additive composed of Cr2O3, MnO, and SiO2. A liquid phase generated during the sintering accelerates grain growth and inhibits reaction between uranium dioxide with steam by forming a film at the grain boundary of the uranium dioxide. This reduces leakage of a fission material by improving high-temperature water vapor oxidation resistance at around 1204° C. in a loss-of-coolant accident condition.

Abstract: A method of manufacturing a zirconium alloy for a nuclear fuel cladding tube includes melting a mixture of 0.5 wt % of Nb, 0.4 wt % of Mo, 0.1 to 0.15 wt % of Cu, 0.15 to 0.2 wt % of Fe, and a balance of zirconium to prepare a melted ingot; heat treating the melted ingot at 1,000 to 1,050° C. for 30 to 40 min. followed by quenching in water to prepare a heat-treated ingot; preheating the heat-treated ingot at 630 to 650° C. for 20 to 30 min. to prepare a preheated ingot followed by hot rolling the preheated ingot at a reduction ratio of 60 to 65% to provide a hot-rolled material; thrice performing vacuum annealing followed by cold-rolling; and vacuum annealing a third cold-rolled material in a final vacuum annealing at 510 to 520° C. for 7 to 9 hrs. to provide the zirconium alloy as a cold-rolled material.

Abstract: The present disclosure relates to a pellet containing an oxide additive to improve a nuclear-fission-gas-adsorption ability of a uranium-dioxide pellet used as nuclear fuel and increase the grain size thereof, and to a method of manufacturing the same. A La2O3—Al2O3—SiO2 sintering additive is added to uranium dioxide so that mass movement is accelerated due to the liquid phase generated during sintering of the uranium-dioxide pellet, which promotes the growth of grains thereof. Further, since less volatilization occurs during sintering due to the low vapor pressure of the liquid phase, efficient additive performance is exhibited, so the liquid phase surrounding the grain boundary effectively adsorbs cesium, which is a nuclear fission gas.

Abstract: Provided is a nuclear-fuel sintered pellet based on oxide in which a plate-type fine precipitate material in a base of a sintered pellet of uranium dioxide, used as nuclear fuel in nuclear power plants, is uniformly dispersed in a matrix of uranium dioxide fuel thereof so as to form a donut-shaped precipitate cluster, and to a method of manufacturing the same. The plate-type fine precipitate material is uniformly precipitated in a tissue thereof or forms a donut-shaped precipitate cluster having a two-dimensional structure through dispersion to improve thermal and physical performance of the nuclear-fuel sintered pellet of uranium dioxide, whereby the creep deformation rate and thermal conductivity of the sintered pellet are improved. The nuclear-fuel sintered pellet based on oxide can reduce the Pellet-Clad Interaction (PCI) failure and the core temperature of nuclear fuel when an accident occurs, thereby significantly improving the safety of a nuclear reactor.

Abstract: Provided is a nuclear fuel pellet having excellent impact resistance, the pellet being prepared with UO2 powder and having a cylindrical shape with a height of 9 to 13 mm and a horizontal cross-section diameter of 8 to 8.5 mm, and including: at each of a top surface and a bottom surface thereof, a dish configured as a spherical groove shape having a predetermined curvature and a groove diameter of 4.8 to 5.2 mm on a center; a shoulder configured as an annular plane along a rim of the dish; and a chamfer configured as a shape in which a corner is chamfered along a rim of the shoulder, wherein a width of the shoulder is 0.20 mm to 0.80 mm, and an angle between the chamfer and a horizontal plane is a 14-degree angle to 18-degree angle.

Abstract: Provided is a nuclear fuel pellet having excellent compression resistance and a reduced missing pellet surface, the pellet being a cylindrical shape and including, on each of a top surface and a bottom surface thereof: a dish configured as a spherical groove shape having a predetermined curved surface at a center; a land configured as a horizontal annular shape along a rim of the dish; and a chamfer configured as a shape in which a corner is chamfered at a predetermined angle along a rim of the land, wherein the chamfer includes: a primary chamfer adjacent to the rim of the land; and a secondary chamfer configured as a shape additionally chamfered along a rim of the primary chamfer.

Abstract: The present invention relates to a recrystallization rate measurement method of zirconium alloy cladding of a nuclear fuel rod, the method including: step 1 of irradiating SEM electron beams at a given scanning interval onto a first specimen to a third specimen which were electrolytically polished and obtaining electron backscattered signals therefrom by an EBSD camera; step 2 of converting electron backscattered signals obtained in step 1 into pattern quality values, respectively, and generating the pattern quality values as frequencies by a specified interval; step 3 of obtaining pattern quality frequencies (B+D) which are a portion of a whole frequency distribution of the second specimen, and pattern quality frequencies (D+E) which are a portion of a whole frequency distribution of the first specimen; and step 4 of obtaining the recrystallization rate of the second specimen with an equation of X ? = ( B + D ) ( D + E ) × 100 , % .

Abstract: A zirconium alloy is manufactured through melting; solution heat treatment at 1,000 to 1,050° C. (?) for 30 to 40 min and ?-quenching using water; preheating at 630 to 650° C. for 20 to 30 min and hot rolling at a reduction ratio of 60 to 65%; primary intermediate vacuum annealing at 570 to 590° C. for 3 to 4 hr and primarily cold-rolled at a reduction ratio of 30 to 40%; secondary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and secondarily cold-rolled at a reduction ratio of 50 to 60%; tertiary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and tertiarily cold-rolled at a reduction ratio of 30 to 40%; and final vacuum annealing at 460 to 590° C. for 7 to 9 hr.

Abstract: Provided is a silicon-carbide-sintered body in which plural crystal grains including silicon carbide are densely formed so as to be adjacent to each other. Sc and Y elements are present in a rich phase at a triple point at which interfaces of the crystal grains forming the sintered body meet each other without solid-solution of the elements in the crystal grains. Accordingly, sintering is feasible at a temperature of 1950° C. or lower, and an EB layer including a rare-earth-Si oxide containing the Sc and Y elements is formed on a surface thereof without an EB coating process, and is also formed up to the inner region of a silicon carbide base, resulting in strong three-dimensional bonding, so that the possibility of peeling of the EB layer is reduced and a new EB layer is formed even when peeling occurs, increasing the resistance to corrosion of the silicon carbide material.

Abstract: The present invention relates to a recrystallization rate measurement method of zirconium alloy cladding of a nuclear fuel rod, the method including: step 1 of irradiating SEM electron beams at a given scanning interval onto a first specimen to a third specimen which were electrolytically polished and obtaining electron backscattered signals therefrom by an EBSD camera; step 2 of converting electron backscattered signals obtained in step 1 into pattern quality values, respectively, and generating the pattern quality values as frequencies by a specified interval; step 3 of obtaining pattern quality frequencies (B+D) which are a portion of a whole frequency distribution of the second specimen, and pattern quality frequencies (D+E) which are a portion of a whole frequency distribution of the first specimen; and step 4 of obtaining the recrystallization rate of the second specimen with an equation of X ? = ( B + D ) ( D + E ) × 100 , % .

Abstract: Disclosed is a method of manufacturing a zirconium alloy plate, wherein fine precipitates having an average size of 35 nm or less are uniformly distributed in a matrix through multi-pass hot rolling, thus increasing corrosion resistance and fatigue failure resistance, the method including forming a zirconium alloy ingot (step 1); subjecting the ingot of step 1 to beta annealing and rapid cooling (step 2); preheating the ingot of step 2 (step 3); forming a multi-pass hot-rolled plate through primary hot rolling and then air cooling during which secondary hot rolling is subsequently conducted (step 4); subjecting the multi-pass hot-rolled plate of step 4 to primary intermediate annealing and primary cold rolling (step 5); subjecting the rolled plate of step 5 to secondary intermediate annealing and secondary cold rolling (step 6); subjecting the rolled plate of step 6 to tertiary intermediate annealing and tertiary cold rolling (step 7); and finally annealing the rolled plate of step 7 (step 8).

Abstract: This invention relates to a composition and method for manufacturing a large-grained uranium oxide nuclear fuel pellet containing an additive. The nuclear fuel pellet is configured such that a uranium oxide powder and an additive powder composed of an Mg compound and a Si compound or Ca compound and a Al compound are mixed together, thus increasing a grain size to thus suppress the release of fission products, thereby increasing the stability of nuclear fuel, preventing cladding tubes from breaking, and contributing to the stable operation of nuclear power plants, ultimately increasing the overall stability of nuclear power plants including nuclear fuel.

Abstract: A zirconium alloy is manufactured through melting; solution heat treatment at 1,000 to 1,050° C. for 30 to 40 min and ?-quenching using water; preheating at 630 to 650° C. for 20 to 30 min and hot rolling at a reduction ratio of 60 to 65%; primary intermediate vacuum annealing at 570 to 590° C. for 3 to 4 hr and primarily cold-rolled at a reduction ratio of 30 to 40%; secondary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and secondarily cold-rolled at a reduction ratio of 50 to 60%; tertiary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and tertiarily cold-rolled at a reduction ratio of 30 to 40%; and final vacuum annealing at 440 to 650° C. for 7 to 9 hr.

Abstract: A zirconium alloy is manufactured through melting; solution heat treatment at 1,000 to 1,050° C. (?) for 30 to 40 min and ?-quenching using water; preheating at 630 to 650° C. for 20 to 30 min and hot rolling at a reduction ratio of 60 to 65%; primary intermediate vacuum annealing at 570 to 590° C. for 3 to 4 hr and primarily cold-rolled at a reduction ratio of 30 to 40%; secondary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and secondarily cold-rolled at a reduction ratio of 50 to 60%; tertiary intermediate vacuum annealing at 560 to 580° C. for 2 to 3 hr and tertiarily cold-rolled at a reduction ratio of 30 to 40%; and final vacuum annealing at 460 to 590° C. for 7 to 9 hr.

Abstract: A short message routing apparatus of a short message transmitting device is disclosed, in which a mobile originated short message is transmitted through a base station, a switching system and a short message system center (SMSC) to a subscriber. The system includes a short message routing control system (SMRS) having a prefix configuration file for routing a short message between the switching system and the SMSC.