Telescoping guide tube and light-water reactor nuclear power station fuel assembly

Abstract

The invention relates to a telescoping guide tube used for a light-water reactor nuclear power station fuel assembly. The telescoping guide tube comprises an inner sleeve and an outer sleeve which is closely sleeved around the inner sleeve; the inner sleeve comprises a large-diameter part, a small-diameter part and a buffering part connecting the large-diameter part with the small-diameter part; inner walls of the large-diameter part, the small-diameter part and the buffering part transit and are connected smoothly; the outer sleeve comprises a sleeve part and a connection part; the sleeve part is closely sleeved around the small-diameter part, and the connection part is in fixed connection with the buffering part. According to the invention, the outer sleeve is closely sleeved around the inner sleeve, which enables the sleeve part and the connection part to be respectively sleeved around the small-diameter part and the buffering part, thereby strengthening the strength of the whole guide tube and further strengthening the strength of the light-water reactor nuclear power station fuel assembly; meanwhile, the buffering part is reinforced, and therefore, control rods are easier to absorb energy when falling, thereby improving bending resistance; fabrication and assembly of the inner sleeve and the outer sleeve are convenient and are easy to realize.

Description

technical field [0001] The invention relates to a fuel assembly of a light water reactor nuclear power plant, and more specifically relates to a casing type guide pipe used in the fuel assembly of a nuclear power plant. Background technique [0002] The fuel assembly of a light water reactor nuclear power plant generally includes five major components, including an upper nozzle 1, a guide tube 2, a grid 3, a fuel rod 4, and a lower nozzle 5, such as Figure 14 shown. The grid 3 is generally assembled from strips, having 17×17 square grids. 25 guide tubes are placed in parallel in the grid of part grid 3. Grid 3 successfully separates guide tubes 2 and controls the distance between guide tubes 2, thus forming a tube bundle. The upper and lower ends of the tube bundle are fixed by the upper tube base 1 and the lower tube base 5, forming the framework of the fuel assembly. The fuel rods 4 are placed in parallel in the grid not occupied by the guide tubes 2 . The coolant flow...

AI Technical Summary

Problems solved by technology

Fuel assemblies assembled from prior art guide tubes have low stiffness and are prone to bending when subject to long-term large axial loads

[0006] Additionally, if Figure 16 As shown, since the lower part of the guide pipe 2 is a relatively dead water zone, as the fuel consumption increases, the foreign matter in the circuit will deposit too much on the lower part of the guide pipe 2

Then there is a risk of foreign matter blocking the screw 6 with the hole, thereby affecting the drop time of the control rods or not sufficiently cooling the relevant rods, or even causing localized boiling in the guide tube 2

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