摘要:
Disclosed are a bottom spacer grid with a louver on a spring that can filter debris flowed through a channel of a lower end fitting with coolant on the lower end fitting of a nuclear fuel assembly, and can prevent uplift of fuel rods due to coolant, simultaneously.The bottom spacer grid for debris filtering with the louver for preventing uplift of the fuel rods, in the spacer grid equipped with a strip dividing a plurality of unit grid cells and a plurality of springs, protruded in uniform directions of each of vertical and horizontal directions on a grid surface of the strip, having uniform elasticity and supporting a lower end cap of a nuclear fuel rod, which includes: a spring having a plane portion with a predetermined size to contact to an outer circumference of the bottom end cap of the nuclear fuel rod; a louver protruded downward the spacer grid at a predetermined angle from the plane portion of the spring; and a debris filtering member bent and protruded to the bottom of the grid surface of the spacer grid.
摘要:
Disclosed are a bottom spacer grid with a louver on a spring that can filter debris flowed through a channel of a lower end fitting with coolant on the lower end fitting of a nuclear fuel assembly, and can prevent uplift of fuel rods due to coolant, simultaneously.The bottom spacer grid for debris filtering with the louver for preventing uplift of the fuel rods, in the spacer grid equipped with a strip dividing a plurality of unit grid cells and a plurality of springs, protruded in uniform directions of each of vertical and horizontal directions on a grid surface of the strip, having uniform elasticity and supporting a lower end cap of a nuclear fuel rod, which includes: a spring having a plane portion with a predetermined size to contact to an outer circumference of the bottom end cap of the nuclear fuel rod; a louver protruded downward the spacer grid at a predetermined angle from the plane portion of the spring; and a debris filtering member bent and protruded to the bottom of the grid surface of the spacer grid.
摘要:
The present invention relates to a top nozzle having on-off type of hold-down springs for a nuclear fuel assembly that has a two-stage elastic section such that a pushing force against the axial movement of the nuclear fuel assembly under normal conditions is optimized and at the same time a suppressing force against a drastic uplifting force of the nuclear fuel assembly under transient conditions is strengthened, and that lowers the elastic coefficients of the springs operating under normal conditions more than those of existing coil springs, thereby providing an optimal pushing force against the nuclear fuel assembly.
摘要:
Disclosed herein are a collagen-based matrix for use as a restorative material and a method for the preparation thereof. An atelocollagen dispersion is spread at a predetermined thickness over a plate and freeze-dried to form a porous collagen membrane. An atelocollagen dispersion is separately spread over a plate and pressurized to form a dense collagen membrane. This is overlaid with the porous collagen membrane and immersed in an EDS solution in ethanol to crosslink the two membranes with each other. From the bilayer structure thus constructed, EDS is removed, followed by lyophilization and cutting into an appropriate size.
摘要:
The present invention relates to an anti-fretting wear spacer grid having a plurality of canoe-shaped springs formed thereon, wherein each of the canoe-shaped springs includes: a fuel rod-contacting part having a flat surface having a predetermined longitudinal length so as to have linear contact with the fuel rod; a curved face-connecting part formed on the upper and lower portions of the fuel rod-contacting part; a leg-connecting part formed on the end portion of the curved face-connecting part; and legs each being formed of a plate shape having a predetermined length and connecting the both sides of the leg-connecting part with one unit grid cell surface.
摘要:
Disclosed herein are a collagen-based matrix for use as a restorative material and a method for the preparation thereof. An atelocollagen dispersion is spread at a predetermined thickness over a plate and freeze-dried to form a porous collagen membrane. An atelocollagen dispersion is separately spread over a plate and pressurized to form a dense collagen membrane. This is overlaid with the porous collagen membrane and immersed in an EDS solution in ethanol to crosslink the two membranes with each other. From the bilayer structure thus constructed, EDS is removed, followed by lyophilization and cutting into an appropriate size.
摘要:
Disclosed herein is a joining structure between a top nozzle and guide thimbles in a nuclear fuel assembly, which can prevent a rotation of inner insertion tube bodies when the top nozzle is separated from the nuclear fuel assembly and promote convenience in assembling and disassembling the top nozzle and the guide thimbles.
摘要:
A joint structure between a top nozzle and a guide thimble of a nuclear fuel assembly and, more particularly, a structure for joining an inner-extension tube, the top nozzle and the guide thimble. When an inner-extension tube head, which is provided as a means for facilitating removal of the top nozzle of the nuclear fuel assembly from the guide thimble, is removed from an inner-extension tube body to separate the top nozzle from the nuclear fuel assembly, the inner-extension tube body is prevented from undesirably rotating, so that the guide thimble and the inner-extension tube body can maintain the joined state.
摘要:
A joint structure between a top nozzle and a guide thimble of a nuclear fuel assembly and, more particularly, a structure for joining an inner-extension tube, the top nozzle and the guide thimble. When an inner-extension tube head, which is provided as a means for facilitating removal of the top nozzle of the nuclear fuel assembly from the guide thimble, is removed from an inner-extension tube body to separate the top nozzle from the nuclear fuel assembly, the inner-extension tube body is prevented from undesirably rotating, so that the guide thimble and the inner-extension tube body can maintain the joined state.
摘要:
Disclosed herein is a joint structure between a top nozzle and a guide thimble. The joint structure includes an outer guide post, an inner-extension tube head, an inner-extension tube body, a wedge and the guide thimble. The outer guide post is provided with an external thread formed on a lower end thereof. The inner-extension tube head includes an annular retaining part formed on an upper end thereof. An internal thread is formed on a medial portion of the inner-extension tube head. An external thread is formed on each of upper and lower ends of the inner-extension tube body. A stop protrusion is provided under a lower end of the wedge. The wedge is welded to the inner-extension tube body after the top nozzle has been joined with the guide thimble. A stop protrusion receiving depression is formed in the guide thimble.