Guide pipe connecting structure capable of eliminating torque and achieving uniform bearing and fuel assembly

Abstract

The invention belongs to the technical field of nuclear reactor fuel assemblies, and particularly discloses a torque-eliminating and uniform-bearing guide pipe connecting structure and a fuel assembly, the torque-eliminating and uniform-bearing guide pipe connecting structure comprises an upper connecting structure and a lower connecting structure; the upper connecting structure comprises an upper tube seat mounting hole, an opening suspension sleeve and a bearing sleeve; a guide pipe with a limiting ring is detachably connected in the mounting hole of the upper pipe seat through an opening suspension sleeve and a bearing sleeve; the lower connecting structure comprises a lower tube seat mounting hole; and the guide pipe end plug is connected with the lower pipe seat mounting hole to form a non-axisymmetric matching structure. Bidirectional locking and uniform bearing of connection are achieved, torque and loosening pieces of the guide pipes in upper connection are eliminated, all the guide pipes are evenly loaded, the bearing capacity of the fuel assembly connecting structure and the guide pipes is improved, the stress level in the operation process is reduced, thermal creep and irradiation creep are relieved, and the service life of the fuel assembly connecting structure is prolonged. And the operation bending of the fuel assembly caused by uneven load is avoided, and the fuel assembly is suitable for being applied to high-fuel-consumption long-circulation fuel assemblies.

Description

technical field [0001] The invention belongs to the technical field of nuclear reactor fuel assemblies, and in particular relates to a torque-eliminating and uniformly loaded guiding pipe connection structure and a fuel assembly. Background technique [0002] The nuclear fuel assembly is composed of a number of fuel rods, positioning grids, guide tubes, upper and lower tube sockets and their connection structures. The connection structure connects the guide tube and the upper nozzle base (hereinafter referred to as the upper connection), and the guide tube and the lower nozzle base (hereinafter referred to as the lower connection) as a whole to realize the continuity of the fuel assembly structure and load transfer functions. [0003] At present, most of the fuel assemblies in service are connected by a detachable structure that is screwed and then bulged to prevent loosening. This connection method needs to apply thread preload, which adds a large load burden to the weak st...

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Problems solved by technology

[0003] At present, the fuel assemblies in service are mostly connected by a detachable structure that is screwed and then bulged to prevent loosening. This connection method needs to apply thread preload, which adds a large load burden to the weak structure of the guide tube, thereby reducing the guide tube. The carrying capacity of the pipe during operation

In addition, when the fuel rods need to be replaced, when both ends are threaded, the disassembled screws cannot be reused as loose parts, and there is a risk of falling and becoming foreign objects; at the same time, the underwater long-distance thread removal of the fuel assembly after irradiation and Reinstallation is also more difficult

[0004] In addition, the prior art such as CN107610785B "Quickly Detachable Connection Device and Method for Guide Tube and Upper Tube Base" also discloses a quick detachable connection structure, but the connection gap between different guide tubes and upper tube bases in the same fuel assembly cannot be guaranteed As a result, the guide tubes with small gaps are excessively loaded, and the guide tubes with large gaps are suspended without loading, and the bearing capacity of all guide tubes is still not exerted.

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