Kepco Nuclear Fuel Co., Ltd.

Korea Institute of Energy Research

Seong Soo Kim

Su Pil Ryu

Joo Hong Chun

Dong Geun Ha

Kyong Bo Eom

Jin Sun Kim

Sang Youn Jeon

Joo Young Ryu

Ba Leum Kim

Nam Gyu Park

Jong Sung Yoo

Jung Min Suh

Joon Kyoo Park

Jae Ik Kim

O Cheol Kwon

Hak In Lee

Oh Joon Kwon

Jeong Geun Kim

Seong Ryong Park

Chong Pyo Cho

Do Gwan Lee

System for separating and coupling a nuclear fuel assembly from/to a top nozzle which has a flow channel plate with guide holes. The system includes a lock insert and a separation member. The lock insert includes an insertion part provided on a top portion of a hollow body. The separation member is configured to separate the insertion part from a guide hole. The insertion part is variable in size. The insertion part comprises a first latching member and a second latching member, each having a step which contacts the flow channel plate. The first latching member includes a latching groove which is inserted into a member protruding from the top surface of the flow channel plate. The second latching member contacts a bottom surface of the flow channel plate. The separation member provides a space accommodating an outer circumferential surface of the first latching member.

System including a member configured to separate a lock insert from a guide hole in a top nozzle plate of a nuclear fuel assembly

Disclosed is a system for separating and coupling a top nozzle of a nuclear fuel assembly. There is provided a lock insert configured to support the top nozzle of the nuclear fuel assembly by being coupled to a guide hole provided in a flow channel plate of the top nozzle, the lock insert including: a body in a hollow shape; and an insertion part provided on a top portion of the body and inserted into the guide hole, wherein a circumference of the insertion part is variable in size, thereby being capable of being inserted into the guide hole. Accordingly, disassembly and reassembly of the top nozzle of the nuclear fuel assembly and the lock insert are simplified, thereby simplifying and reducing the number of processes involved therein. Accordingly, the system is effective for maintenance and repair of the nuclear fuel assembly.

System for separating and coupling top nozzle of nuclear fuel assembly

Embodiments of a bottom nozzle of a nuclear fuel assembly provided with flow holes by utilizing a layered aircraft airfoil structure are provided. The bottom nozzle not only increases efficiency of filtering foreign substances by minimizing a size of the flow holes by constituting a shape of flow holes into cross stripes but also prevents coolant water flow velocity drop through prevention of coolant water pressure drop by constituting a lateral sectional shape of the grid frames constituting the cross stripes into an aircraft airfoil type.

Bottom nozzle of nuclear fuel assembly provided with flow holes by utilizing layered aircraft airfoil structure

The present disclosure relates to a decompression apparatus for superheated steam comprising: a temperature raising unit having an inlet connected to an exit side of a boiler for introducing steam discharged from the exit of the boiler, and an outlet for raising the temperature of steam introduced through the inlet and discharging it; a steam utilizing unit connected to the outlet and using the steam discharged from the outlet; and a decompression unit installed at one or all of a section between the exit side of the boiler and the inlet and a section between the outlet and the steam utilizing unit, the decompression unit controlling temperature of steam while decompressing pressure of steam. According to the decompression apparatus for superheated steam, it is possible to control the pressure and temperature of steam more precisely.

Decompression apparatus for superheated steam

The present invention relates to a top nozzle and a nuclear reactor in which an in-core instrument, which is supposed to be inserted through a top head of a nuclear reactor, is inserted through a guide pin for an upper core plate. In a nuclear reactor including guide pins for aligning a top nozzle for a nuclear fuel assembly with an upper core plate of a nuclear reactor, a guide hole () is axially formed through the guide pins () and in-core instruments () are inserted through the guide holes ().

Nuclear fuel assembly top nozzle having in-core instrument insertion structure using an upper core plate hollow guide pin

The present invention relates to a lower end fitting for reducing flow resistance due to an in-core instrument in a nuclear fuel assembly, that is, a lower end fitting () having a plurality of flow holes for a nuclear fuel assembly, in which the flow holes () are formed under an assembly groove in which an instrumentation tube () for a nuclear fuel assembly is inserted, and at least two or more flow holes () are formed at a predetermined distance from the central axis (C) of the instrumentation tube ().

Lower end fixing body for improving flow path resistance of in-core detector

Disclosed herein is a spacer grid for a nuclear fuel assembly which is formed from grid strips of an improved structure, thus reducing flow-induced high-frequency vibration. The spacer grid has dimples or grid springs for supporting fuel rods and is formed from a plurality of grid strips assembled in a lattice shape to form lattice cells. Each of the grid strips has at least one slot formed in a planar portion of the grid strip separately from the dimple or grid spring. Therefore, characteristics of the vibration of the spacer grid can be set in a variety of different manners so that flow-induced high-frequency vibration can be reduced.

Spacer grid for nuclear fuel assembly for reducing high frequency vibration

Disclosed herein is a spacer grid for a nuclear fuel assembly. The spacer grid has dimples for supporting fuel rods and is formed from grid strips which are assembled in a lattice shape to form lattice cells. Each grid strip has at least one hole which is formed separately from the dimples. Therefore, when coolant is drawn into the fuel assembly, a pressure difference between opposite sides of the holes is reduced, and friction generated between cut edges of the holes and the coolant reduces the magnitude of the vibration and causes a damping effect, thus reducing flow-induced vibration. The hole formed in the grid strip function to widen the range of the frequency of the flow-induced vibration caused by vortex sheddings formed around the edges of the grid strip, thus reducing the possibility of the generation of resonance with the natural frequency of the spacer grid.

Growing community of inventors

Daejeon, South Korea

Seong Soo Kim