Korea Nuclear Fuel or KNF is a South Korean public enterprise established in 1982 to provide high quality nuclear fuel. It provides nuclear fuels to 20 nuclear power plants in South Korea. The price of the nuclear fuel provided by the company accounts for 60% of the average international price. Wikipedia.
Ha S.J.,Korea Electric Power Research Institute |
Park C.E.,KEPCO Engineering and Construction Company Inc. |
Kim K.D.,Korea Atomic Energy Research Institute |
Ban C.H.,Korea Nuclear Fuel Co.
Nuclear Engineering and Technology | Year: 2011
The Korean nuclear industry is developing a thermal-hydraulic analysis code for safety analysis of pressurized water reactors (PWRs). The new code is called the Safety and Performance Analysis Code for Nuclear Power Plants (SPACE). The SPACE code adopts advanced physical modeling of two-phase flows, mainly two-fluid three-field models which comprise gas, continuous liquid, and droplet fields and has the capability to simulate 3D effects by the use of structured and/or nonstructured meshes. The programming language for the SPACE code is C++ for object-oriented code architecture. The SPACE code will replace outdated vendor supplied codes and will be used for the safety analysis of operating PWRs and the design of advanced reactors. This paper describes the overall features of the SPACE code and shows the code assessment results for several conceptual and separate effect test problems.
Cho M.S.,Korea Atomic Energy Research Institute |
Lee S.J.,Korea Nuclear Fuel Co. |
Lee Y.S.,Daejeon University
Transactions of the American Nuclear Society | Year: 2010
Thermal load simulation and verification experiments of a very high temperature irradiation of TRISO coated particle fuels in HANARO research reactor were carried out to verify the feasibility of irradiation rod designs. Results of the experiments were used to develop and verify a COMSOL based finite element heat transfer model that will be used as a basis for an optimum design of an irradiation test rod.
Ryu S.-H.,Korea Nuclear Fuel Co. |
Park G.-C.,Seoul National University
Nuclear Engineering and Design | Year: 2011
Droplets are generated at the interface of annular flow due to an interaction between a liquid film and gas core flow. Therefore, knowledge of the interfacial wave structure is essential for making an accurate prediction of the amount of entrained droplets. A new droplet entrainment model was proposed based on the force balance of interfacial waves in vertical annular flow. An analytic wave shape function was developed reflecting the detailed experimental findings, and was used in the development of a new model. The model was validated using the experimental data reported by Hewitt and Pulling at low pressures and by Keeys et al. at high pressures, which had been performed in adiabatic vertical tubes. The root-mean-square error of the prediction of the amount of entrainment was approximately 27% when the model was implemented into COBRA-TF code, which is approximately 23% less than that determined by the Würtz model. The models proposed by Okawa et al. and Stevanovic et al. were also implemented into COBRA-TF and compared with the proposed model. © 2011 Published by Elsevier B.V.
Kim Y.-S.,Hanyang University |
Jeong Y.-H.,Korea Atomic Energy Research Institute |
Son S.-B.,Korea Nuclear Fuel Co.
Journal of Nuclear Materials | Year: 2014
The effects of dissolved hydrogen on oxide phase transformation and micro-structural changes during zirconium oxide growth were investigated using Raman spectroscopy and Transmission Electron Microscopy (TEM). Raman spectra measurements show that tetragonal zirconia develops during oxide growth and a fraction of the phase in pre-hydrided alloy is consistently lower than that of an un-hydrided one. This was observed identically in both Zircaloy-4 and Zr-1.5Nb alloys. TEM analysis at the metal-oxide interface support that the Raman spectra changes resulted from micro-structural changes. These results suggest that the dissolved hydrogen may cause meta-stabilization of the tetragonal phase oxide grown at the metal-oxide interface, probably by relaxing the compressive stress built up at the interface, or by modifying the stress distribution over the interface. The relaxation or modification possibly comes from the mitigation of the lattice incoherency between the metal and the oxide at the interface that is the origin of the compressive stress build-up. © 2013 Elsevier B.V. All rights reserved.
Jang J.-H.,Korea Nuclear Fuel Co. |
Kang H.-S.,Korea Nuclear Fuel Co. |
Lee Y.-S.,Korea Nuclear Fuel Co. |
Lee H.,Korea Nuclear Fuel Co. |
Kim J.-G.,Korea Nuclear Fuel Co.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2013
A continuous ingot casting process was developed to improve the productivity of ingot fabrication. A supplemental charge method in which uranium dendrites were additionally added into molten uranium was introduced for the first time, and a tilting system of a melting crucible to mold was developed. The feasibility of these processes was confirmed by a uranium melting test at the laboratory scale, successfully obtaining a uranium ingot in about 4.6 kg. Based on the results, we scaled up the ingot casting processes at the engineering scale. A rotating continuous feeder was installed for the ceaseless feeding of the dendrites into molten uranium. The tilting system and eight mold crucibles on a turn-table were adopted. The operability of the continuous ingot casting process at the engineering scale was successfully confirmed by a melting test of copper. We consider that the engineering scale equipment can cast above a 50 kg U/batch with the continuous casting processes. © 2012 Akadémiai Kiadó, Budapest, Hungary.
Jang J.,Korea Nuclear Fuel Co. |
Lee H.-S.,Korea Nuclear Fuel Co. |
Lee S.,Korea Nuclear Fuel Co.
Journal of Radioanalytical and Nuclear Chemistry | Year: 2016
The high-temperature stability of ZrN and TiN coatings deposited by plasma spraying on graphite crucibles for melting uranium was investigated. A layer of mixed Zr (or Ti) oxide and nitride was formed with a thickness of 80–100 μm. The chemical stability was evaluated by a melting test with uranium at 1400 °C. The ZrN layer disappeared after the melting test, but the TiN layer remained stable. The thermal stability was evaluated by heating up to 1400 °C; the surface of the crucible coated with ZrN flaked off after this test, whereas the surface of the crucible coated with TiN remained almost intact. © 2016 Akadémiai Kiadó, Budapest, Hungary
Korea Nuclear Fuel Co. | Date: 2010-01-13
Disclosed therein are an apparatus for and a method of automatically welding a flange to a guide thimble tube in a nuclear fuel assembly. The automatic welding apparatus includes: a welding part located on an axially conveying line of a tube for welding a welded surface of the tube inserted thereinto and a welded surface of a flange; a flange supplying part for supplying the flange at a tube inlet of the welding part onto the axially conveying line; and a conveying part mounted on the axially conveying line in such a way as to move the tube and the flange on the axially conveying line, so that they are inserted into and drawn from the welding part.
Korea Nuclear Fuel Co. | Date: 2012-06-15
A top nozzle is provided. The top nozzle can include a coupling plate, a perimeter wall and a hold-down spring unit. The coupling plate can be coupled to a guide thimble of the nuclear fuel assembly. The perimeter wall can protrude upwards from the perimeter of the coupling plate. A spring clamp can be provided on the upper surface of the perimeter wall. The hold-down spring unit can be mounted to the upper surface of the perimeter wall in such a way to couple a corresponding end of the hold-down spring unit to the spring clamp. A fastening pin hole can be vertically formed through an upper surface of the spring clamp. A spring insert hole into which the hold-down spring unit can be inserted and formed by electro-discharge machining in an insert direction of the hold-down spring.
Korea Nuclear Fuel Co. | Date: 2012-06-20
A hold-down spring unit for a top nozzle of a nuclear fuel assembly. The hold-down spring unit is coupled to the upper end of the top nozzle of the nuclear fuel assembly. The hold-down spring unit includes a first spring which provides a hold-down force upon the nuclear fuel assembly under start-up conditions or hot full power conditions of a nuclear reactor, and a second spring which provides an additional hold-down force upon the nuclear fuel assembly under start-up conditions of the nuclear reactor. The hold-down margin under start-up conditions or hot full power conditions is reduced, thus enhancing the mechanical and structural stability of the nuclear fuel assembly.
Korea Nuclear Fuel Co. | Date: 2013-10-31
Disclosed therein are an apparatus for and a method of welding a flange to a guide thimble tube in a nuclear fuel assembly. The automatic welding apparatus includes a welding unit located on an axially conveying line of a tube for welding a surface of the tube inserted thereinto and a surface of a flange, a flange supplying unit for supplying the flange at a tube inlet of the welding unit onto the axially conveying line, and a conveying unit mounted on the axially conveying line in such a way as to move the tube and the flange on the axially conveying line, so that they are inserted into and drawn from the welding unit.