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Stress-fatigue-resistant single-metal positioning grid for pressurized water reactor fuel assembly

A technology for positioning grids and fuel assemblies, applied in the directions of reactor fuel elements, fuel element assembly, reactors, etc., can solve problems such as fatigue cracks and increased cyclic stress of clamping structures, and achieve ease of fretting wear and a simple structure. , the effect of prolonging the service life

Active Publication Date: 2020-09-01
NUCLEAR POWER INSTITUTE OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At the same time, due to the rapid relaxation of the single metal grid, after the fuel rods are separated from the clamping structure, the action mode changes from friction to impact, resulting in an increase in the cyclic stress of the clamping structure, and fatigue cracks are more likely to occur

Method used

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  • Stress-fatigue-resistant single-metal positioning grid for pressurized water reactor fuel assembly
  • Stress-fatigue-resistant single-metal positioning grid for pressurized water reactor fuel assembly
  • Stress-fatigue-resistant single-metal positioning grid for pressurized water reactor fuel assembly

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] like Figure 1 to Figure 4 As shown, a single metal positioning grid of a pressurized water reactor fuel assembly resistant to stress fatigue includes strips 2 for surrounding the positioning grid, springs 3 are arranged on the strips 2, and springs 3 are arranged on the strips. A plurality of stress relief grooves on 2, the stress relief grooves are arranged around the spring 3: the spring 3 is located in the area surrounded by the plurality of stress relief grooves, and the stress relief grooves are all strip-shaped grooves running through the inside and outside of the strip 2.

[0033] In the prior art, in order to reduce the positioning damage and wear of the fuel rods 1, when designing the fuel assembly positioning grid, the springs 3 arranged on the strips 2 are generally adopted to have an overall lower stiffness. More specifically, in view of the above overall low stiffness characteristics, if the spring 3 is designed as a multi-bending structure as a whole, thi...

Embodiment 2

[0036] The present embodiment is further limited on the basis of embodiment 1, as Figure 1 to Figure 4 As shown, as a specific solution of the spring 3 , it is set as follows: the spring 3 has an elliptical spherical shell structure, and the long axis direction of the spring 3 is parallel to the length direction of the strip 2 . In this solution, the above spring 3 not only has a simple structure, but also increases the contact length between the spring 3 on the positioning grid and the fuel rod 1, thereby reducing the abrasion depth corresponding to the same abrasion volume. By adopting this solution, the structural design of the spring 3 also has the characteristics of being convenient for pulling and inserting the fuel rod 1 . Combining the above technical scheme including stress relief grooves, in order to facilitate the description of the design features of this scheme, the following prior art is provided: "H" shaped spring 3 grids and "I" shaped spring 3 grids of Americ...

Embodiment 3

[0048] The present embodiment is further limited on the basis of embodiment 1, as Figure 1 to Figure 4 As shown: as a more complete technical solution for the positioning grid, it is set as follows: the positioning grid is a rectangular tube structure surrounded by four strips 2, and two springs 3 and four springs are arranged on the positioning grid. Rigid convex 4, each spring 3 is matched with two rigid convex 4, the matching spring 3 and rigid convex 4 have the following relationship: in the length direction of the strip 2, the spring 3 is located in the middle of one of the strips 2, and the rigid convex 4 The protrusion 4 is located on the opposite side of the spring 3, and both the upper and lower sides of the spring 3 have a rigid protrusion 4. This scheme provides a rectangular positioning grid. When the positioning grid is used in practice, the matching spring 3 and the rigid protrusion 4 form a clamping station for clamping the fuel rod 1, that is: this scheme prov...

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Abstract

The invention discloses a stress-fatigue-resistant single-metal positioning grid for a pressurized water reactor fuel assembly. The positioning grid comprises strips used for defining the positioninggrid, and springs are arranged on the strips. The positioning grid further comprises a plurality of stress release grooves formed in the strips, the stress release grooves are formed around the springs, the springs are located in the areas defined by the stress release grooves, and the stress release grooves are strip-shaped grooves penetrating through the inner sides and the outer sides of the strips. Due to the structural design of the positioning grid, stress on the springs can be effectively released to the strips, so that the possibility of fatigue fracture failure of the springs is reduced.

Description

technical field [0001] The invention relates to the technical field of fuel assemblies for pressurized water reactor nuclear power plants, in particular to a single metal positioning grid for pressurized water reactor fuel assemblies that resists stress fatigue. Background technique [0002] The fuel assembly is one of the core components of the pressurized water reactor, and its main function is to release energy through the fission of the nuclear fuel in the fuel rod and to export energy through the coolant. [0003] A commonly used PWR fuel assembly consists of a fuel skeleton and several fuel rods. Usually, the fuel skeleton consists of several guide tubes, instrument tubes, several spacer grids and upper and lower tube bases. The spacer grids are welded and fixed on the guide tubes and the instrument tubes, and the fuel rods are clamped by the spacer grids. The positioning grid is an important part of the fuel assembly, and its main function is to maintain the lateral ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G21C3/34
CPCG21C3/3424G21C3/3432Y02E30/30
Inventor 郑美银陈平雷涛焦拥军秦勉李权肖忠陈杰彭园黄永忠蒲曾坪
Owner NUCLEAR POWER INSTITUTE OF CHINA
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