Nuclear fuel assembly guiding tube

Abstract

The invention discloses a nuclear fuel assembly guiding tube. The nuclear fuel assembly guiding tube comprises an outer tube and an end plug, wherein two ends of the outer tube are open; the end plugis used for sealing the opening of the lower end of the outer tube; at least one inner tube is fixed on the inner peripheral wall of the outer tube; and the lower end surface of the outer tube is parallel and level to the lower end surface of the inner tube. For solving the problems that in the prior art, a guiding tube is complicated in structure, positioning fit difficulty is high after expansion, an expansion portion of the guiding tube fails easily, and thus, the framework of a whole fuel assembly fails, a traditional guiding tube designing mode is abandoned, double-layered design of an outer tube and an inner tube is adopted, after being parallel and level to the lower end surface of the outer tube, the lower end surface of the inner tube is connected with the end plug so as to achieve the buffering effect which meets the requirement for the fuel assembly, sufficient rigidity of the guiding tube is ensured, and then the anti-seismic property of the nuclear fuel assembly guiding tube is improved.

Description

technical field [0001] The invention relates to the technical field of nuclear reactor fuel assemblies, in particular to a nuclear fuel assembly guide pipe. Background technique [0002] The nuclear fuel assembly is composed of a number of fuel rods, guide tube parts, positioning grids, upper and lower tube seats, etc. The guide tube part is the load-bearing part of the fuel assembly skeleton, and its basic functions are as follows: provide continuity for the fuel assembly structure; provide insertion channels for fuel-related components; provide hydraulic buffer for the drop of control rods during reactor emergency shutdown; provide fuel-related component rods Provides coolant flow. [0003] At present, the typical guide tube structures of PWR fuel assemblies mainly include AFA3G guide tube and AP1000 guide tube). The AFA3G guide tube is a MonoblocTM guide tube, which adopts the design of increased wall thickness of the buffer section, the outer diameter of the guide tube...

AI Technical Summary

Problems solved by technology

The structure of the MonoblocTM guide tube is simple, but the rolling process of the guide tube is relatively difficult, and this process has not yet been mastered in China; the AP1000 guide tube is a tube-in-tube structure, and the buffer tube is placed at the lower end of the guide tube, and the two are matched through their respective end plugs , but although the AP1000 guide tube avoids the difficult rolling process of the AFA3G guide tube, the buffer tube and end plug are added, the structure is more complicated, and the positioning and matching are more difficult

In addition, the AP1000 guide tube needs to be expanded with the bottom grid casing first, and then inserted into the internal buffer tube for expansion to form a guide tube component. There is a risk that the entire fuel assembly skeleton will fail due to the failure of the guide tube component expansion, and the expansion process is difficult. bigger

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