Abstract: Provided are a tube sheet of a steam generator installed to support a tube of the steam generator, and a manufacturing method thereof, particularly, a tube sheet of a steam generator having an anticorrosive layer and a manufacturing method thereof.

Abstract: An apparatus and method for safely controlling a control rod of a nuclear reactor for a nuclear power plant is provided. The apparatus may include a first controller to output a signal to insert or withdraw the control rod, a mechanical portion to perform insertion or withdrawal of the control rod in response to the signal output by the first controller, the mechanical portion including a movement process portion, a stop latch to restrain the control rod, a moving latch to move the control rod, and a lift coil to insert or withdraw the control rod, a detector to detect a position or a speed of the control rod when the control rod is inserted or withdrawn, and a brake to stop the control rod by force when the control rod is withdrawn irrespective of an intended control of the control rod.

Abstract: Disclosed is a heat exchanger for a passive residual heat removal system, which improves heat transfer efficiency by expanding a heat transfer area. A heat exchange tube includes a first member connected to a steam pipe through which steam generated from a steam generator of a nuclear reactor circulates, and a second member connected to both of the first member and a feed water pipe used to supply water to the steam generator provided in the nuclear reactor, and the first member has the shape different from that of the second member, thereby expanding the heat transfer area so that the heat transfer efficiency is improved.

Abstract: A zirconium alloy for use in nuclear fuel assemblies is provided, which provides increased resistance against oxidation and corrosion and also improved bonding with parent material, because pure metallic material such as silicon (Si) or chromium (Cr) is evenly coated on the surface of the parent material by plasma spraying. Because the plasma spray coating used to coat the pure metallic material on the zirconium alloy does not require vacuum equipment and also is not limited due to the shape of the coated product, this is particularly useful when evenly treating the surface of the component such as 4 m-long tube or spacer grip arrangement which is very complicated in shape. Furthermore, because the coated zirconium alloy confers excellent resistance to oxidation and corrosion under emergency such as accident as well as normal service condition, both the economic and safety aspects of nuclear fuel are improved.

Abstract: The present invention provides a technique for adsorbing I-125 on a support for treating cancer and a method of preparing an I-125 seed using the same. Since a method of preparing iodine according to the present invention uses an intermediate having phosphate-based, oxalate-based, or arsenate-based anions introduced thereinto, the intermediate has a substitution effect of iodine 3 to 5 times higher than that of a typically used intermediate having chlorine anions introduced thereinto. According to the substitution effect, control of a radiation dose may be possible during the manufacturing of an iodine seed and an iodine seed may be prepared within a shorter period of time. Also, since an amount of residual radioactive iodine may be decreased as a result of a large amount of adsorption, an amount of radioactive iodine (I-125) waste may be decreased, and the effect thereof may be also high environmentally.

Abstract: The present invention relates to a novel method for increasing saccharification efficiency by adding chaperone protein during saccharification process, more precisely a composition for increasing saccharification efficiency of biomass containing cellulose using peroxiredoxin (Prx) protein and a method for increasing glucose yield by using the same. The conventional saccharification process has the disadvantage of decreasing cellulase activity, suggesting that the high priced saccharogenic enzyme has to be continuously supplied since the saccharogenic enzyme is losing its activity continuously by reducing sugar through the whole saccharification process. Therefore, to increase saccharification efficiency, the present invention provides a method characterized by increasing saccharification efficiency by preventing cellulase from losing its activity throughout the whole saccharification process by using chaperone protein, particularly Prx protein herein, together with cellulase.

Abstract: A monitoring method of metal ions or oxygen ions applicable to a high concentration non-aqueous electrolyte includes: applying a potential in a non-aqueous electrolyte to obtain current information with respect to the potential; varying the potential applied in the non-aqueous electrolyte containing metal ion concentration or oxygen ion concentration such that the metal ion concentration or the oxygen ion concentration is maintained in spite of the potential being applied; detecting a linear relationship among the concentration, the current, and passed charges in the non-aqueous electrolyte by repeatedly performing the obtaining step and the varying step, while changing the concentration; and calculating metal ion concentration or oxygen ion concentration of the non-aqueous electrolyte in pyroprocessing of the non-aqueous electrolyte by using the linear relationship.

Abstract: Disclosed are a zirconium alloy for a nuclear fuel cladding having a good oxidation resistance in reactor accident conditions, a zirconium alloy nuclear fuel cladding prepared by using thereof and a method of preparing the same. The zirconium alloy includes 1.0 to 1.2 wt % of niobium (Nb); at least one element selected from tin (Sn), iron (Fe) and chromium (Cr); 0.02 to 0.1 wt % of copper (Cu); 0.1 to 0.15 wt % of oxygen (0); 0.008 to 0.012 wt % of silicon (Si) and a remaining amount of zirconium (Zr). The amount of Sn is 0.1 to 0.3 wt %, the amount of Fe is 0.3 to 0.8 wt %, and the amount of Cr is 0.1 to 0.3 wt %. A good oxidation resistance of the nuclear fuel cladding may be confirmed under accident conditions as well as normal operating conditions of a reactor, thereby improving economic efficiency and safety.

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: Disclosed are a zirconium alloy for a nuclear fuel cladding having a good oxidation resistance in a severe reactor operation condition and a method of preparing zirconium alloy nuclear fuel claddings by using thereof. The zirconium alloy includes 1.8 to 2.0 wt % of niobium (Nb); at least one element selected from iron (Fe), chromium (Cr) and copper (Cu); 0.1 to 0.15 wt % of oxygen (O); 0.008 to 0.012 wt % of silicon (Si) and a remaining amount of zirconium (Zr). The amount of Fe is 0.1 to 0.4 wt %, the amount of Cr is 0.05 to 0.2 wt %, and the amount of Cu is 0.03 to 0.2 wt %. A good oxidation resistance of the nuclear fuel cladding may be confirmed under a severe reactor operation condition at an accident condition as well as a normal operating condition of a reactor, thereby improving economic efficiency and safety.

Abstract: A method for fabricating porous UO2 sintered pellets to be fed into an electrolytic reduction process for the purpose of metallic nuclear fuel recovery is provided, which includes forming a powder containing U3O8 by oxidizing a spent nuclear fuel containing uranium dioxide (UO2) (step 1), fabricating U3O8 green pellets by compacting the powder formed in step 1 (step 2), and fabricating UO2 sintered pellets by sintering the U3O8 green pellets fabricated in step 2 at 1000 to 1600° C., in an atmospheric gas, and cooling the same for reduction, by changing the atmosphere to a reducing atmospheric gas (step 3). The porous UO2 sintered pellets can be fabricated, which do not have any defects. The volatile fission products are sufficiently removed from the fabricated porous UO2 sintered pellet, the O/U ratio is 2.00, the permeation of the electrolyte during reduction is facilitated, and the electrolytic reduction velocity increases.

Abstract: A nuclear fuel rod for a fast reactor includes tubular fuel materials comprising a hollow portion formed therein, a tubular inner pipe inserted into the hollow portion of the tubular fuel materials to prevent collapse of the tubular fuel materials due to combustion of nuclear fuel, a tubular cladding pipe which surrounds the tubular fuel materials, and a liquid metal, or He gas or vacuum applied in a gap between the tubular fuel materials and the tubular cladding pipe.

Abstract: A method for fabricating porous UO2 sintered pellets to be fed into the electrolytic reduction process for the purpose of metallic nuclear fuel recovery is provided, which includes forming a powder containing U3O8 by oxidizing spent nuclear fuel containing uranium dioxide (UO2) (step 1), fabricating green pellets by compacting the powder formed in step 1 (step 2), fabricating UO2+x sintered pellets by sintering the porous U3O8 green pellets fabricated in step 2 at 1200 to 1600° C., in an atmospheric gas (step 3), and forming UO2 sintered pellets by cooling the UO2+x sintered pellets to room temperature, and reduction the same at 1000 to 1400° C., in a reducing atmosphere (step 4).