WO2014173139A1

WO2014173139A1 - Fuel component upper tube socket

Info

Publication number: WO2014173139A1
Application number: PCT/CN2013/089190
Authority: WO
Inventors: 黄春兰; 雷涛; 茹俊; 青涛; 蒲曾坪; 肖忠; 焦拥军; 雍泾; 张�林; 程华旸
Original assignee: 中国核动力研究设计院
Priority date: 2013-04-24
Filing date: 2013-12-12
Publication date: 2014-10-30
Also published as: ZA201505858B; GB2524456A; GB2524456B; CN203376983U; AR095871A1; CN103413576B; GB201513652D0; CN103413576A; CN103247352A

Abstract

A fuel component upper tube socket is mainly formed of a connecting board (2), a surrounding board (3) fixed at an edge of the connecting board (2), and a frame board (4) fixed on the surrounding board (3). A connecting hole A (5) for installing a fuel component guide tube and a connecting hole B (6) for installing a meter tube are opened on the connecting board (2). A plurality of water flow holes in an overall long-strip shape is opened evenly on the connecting board (2). The water flow holes comprise a water flow hole A (201) and a water flow hole B (202), and an included angle greater than 0° exists between axial lines of the water flow hole A (201) and the water flow hole B (202). The advantages and beneficial effects of the upper tube socket lie in that, by changing the shape and arrangement manner of water flow holes, the water flow holes can be evenly arranged, and meanwhile a flow area proportion is increased, so that technical problems of low economic efficiency of an upper tube socket and undesirable flow field distribution of outlets of fuel components are solved.

Description

Fuel assembly upper header

TECHNICAL FIELD The present invention relates to the field of nuclear industry, and in particular to a fuel assembly upper header. BACKGROUND OF THE INVENTION A nuclear fuel assembly is composed of a plurality of fuel rods, a guide tube, a positioning grid, and upper and lower tubes. The structure is shown in Figure 1. Among them, the upper header 1 serves as a key component to laterally position the fuel assembly, to withstand and transmit the pressing force, to provide an outlet cavity for the coolant, to provide an interface for the fuel assembly lifting, and to prevent the fuel rod from being ejected. Some fuel assemblies are mainly composed of a connecting plate, a surrounding plate and a frame plate. In Fig. 2, a connecting plate of a conventional upper header is shown. The connecting plate is substantially square, and a circular instrument tube connecting hole and a guiding tube connecting hole and a plurality of elongated water flowing holes are formed in the connecting plate. The existing upper header has the following problems:

1. The arrangement of the flow holes is not good, so the number of flow holes is small, which directly leads to a lower proportion of the flow area on the connection plate, and the pressure drop on the lower side of the connection plate is larger. In this case, more consumption is required. The main pump head can make the cooling water flow meet the requirements, and the economy is not good;

2. The flow holes are asymmetrically arranged, which has an adverse effect on the flow field distribution at the outlet of the fuel assembly. When the cooling water is distributed after passing through the upper pipe seat, it is easy to generate lateral flow, and the control rod and the combustible poison rod are vibrated and abraded to cause failure. risks of. Summary of the invention

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fuel assembly upper header that overcomes the disadvantages of the current upper housing economy and the disadvantages of the field distribution of the fuel assembly outlet.

The object of the invention is achieved by the following technical solutions: The upper part of the fuel assembly is mainly composed of a connecting plate, a surrounding plate fixed to the edge of the connecting plate and a frame plate fixed on the surrounding plate, and the connecting plate is provided with a connecting hole A for mounting the fuel assembly guiding pipe and for installing the instrument a connecting hole B of the pipe, wherein a plurality of elongated water-flow holes are uniformly formed on the connecting plate, the water-flow hole includes a water-flow hole A and a water-flow hole B, and there is more than 0° between the axes of the water-flow hole A and the water-flow hole B An angle formed between the two axially adjacent water holes A and the two water holes B on the connecting plate; on the connecting plate, two radially adjacent water holes A A surrounding portion is formed between the two water flowing holes B. The connecting plate is further provided with a central water flowing hole, and the connecting hole A, the connecting hole B and the central flowing water hole are respectively disposed on the surrounding portion.

To overcome the deficiencies of the prior art, the main technical problem to be solved is how to more uniformly arrange the flow holes with a larger total area. The inventors divided the flow holes into non-parallel flow holes A and flow holes B, and arranged the flow holes A and the flow holes B as a whole in an intersecting manner. Compared with the parallel arrangement in the prior art, the way of the cross arrangement can balance the arrangement of the connection hole A, the connection hole B and the central flow hole as much as possible, and arrange the flow holes as much as possible to increase the proportion of the flow area on the connection plate. Thereby, the purpose of reducing the pressure drop on the lower side of the connecting plate is achieved. The connecting portion functions to maintain the integrity of the connecting plate. On the basis of ensuring the structural strength of the connecting plate, the area of the connecting portion can be minimized, so that the proportion of the flow area on the connecting plate is maximized. In addition, subject to the arrangement of the connection hole A, the connection hole B and the central flow hole, the parallel arrangement in the prior art can only fill the remaining space on the connection plate by setting different sizes of flow holes when implemented. Moreover, the arrangement of the water holes cannot be symmetrical, which results in uneven water output through the connecting plates, which greatly affects the flow field distribution at the outlet of the fuel assembly. Arranged in an intersecting manner, the flow holes surrounding the connection hole A and the connection hole B can be processed to be uniform in size, and the connection holes A and the connection holes B are evenly arranged. In the present invention, the amount of water discharged from the connecting plates is the same, which does not affect the flow field distribution at the outlet of the fuel assembly, and avoids the problem of lateral flow.

As a first optimization of the present invention, the flow hole is rectangular. On the basis of ensuring the structural strength of the connecting plate, the rectangular flow hole can make the linear distance between the connecting hole A and the connecting hole B and the flowing hole Recently, the proportion of the flow area on the splicing plate has been increased.

As a second optimization scheme of the present invention, the side surface of the flow hole is concavely formed to form a circular arc surface A, and the curvature of the circular arc surface A matches the curvature of the adjacent connecting hole A, the connecting hole B or the central flowing water hole. By setting the arc surface A, the material distribution between the flow hole and the connection hole, the connection hole B or the central flow hole can be more evenly distributed, and there is no weak portion, and the structural strength of the connection plate can be reduced while taking into consideration the ratio of the flow area. Impact. It can be seen that, on the basis of ensuring the structural strength of the connecting plate, the distance between the circular arc surface A and the connecting hole A, the connecting hole B or the central flowing water hole can be as small as possible.

As a further optimization of the second optimization scheme of the present invention, the end surface of the flow hole is convexly formed to form a circular arc surface B, so that the water flow hole forms a structure with a narrow inner end and a smooth edge, which increases the flow area ratio and can It relieves the stress concentration at the edge of the flow hole.

As a further optimization of the second optimization scheme of the present invention, the end faces of the flow holes are convexly formed into lobes having straight lines on both sides. This optimization also increases the flow area ratio, and the lobes have a longer extendable length in the axial direction. It should be noted that the top of the lobes may be a circular arc shape, or may be a straight angle or other shape. The shape of the top of the lobes is mainly selected according to the physical properties of the materials constituting the connecting plate. For materials with better stress concentration resistance, a straight angle can be preferentially selected to obtain a longer extension length.

Further, adjacent sides of the adjacent lobes are parallel. The optimization can evenly distribute the material between the two sides, and the distribution of the materials on the connecting plate is more uniform and uniform, and the structural strength of the connecting plate is improved. It can be seen that in this case, it is possible to further enlarge the area of the flow hole so that the strength of the connecting plate is close to the acceptable bottom line, thereby obtaining the maximum flow area ratio.

As a third optimization of the present invention, in the above aspect, the connection hole A and the center water flow hole are alternately arranged, and the connection hole B is opened on a surrounding portion at a center position of the connection plate. This optimization can converge the flow of cooling water flowing out of the connecting plates, and further reduces the influence on the flow field distribution at the outlet of the fuel assembly.

As a fourth optimization scheme of the present invention, on the basis of the foregoing solution, the connecting board is further The flow hole C, the flow hole D and the flow hole E are opened, and the flow hole C is a circular hole or a rounded rectangular hole, and the flow hole C is disposed at the four corners of the connecting plate and arranged in a rectangular array, the flow hole D and the flowing water The hole E is a long hole having a convex arc at both ends, and the length of the water flow hole E is shorter than the length of the water flow hole D, and the water flow hole D and the water flow hole E are provided at the edge of the connection plate. The webs are square, and if the water holes are also arranged in an intersecting manner at their edges, the material distribution at the edges will be uneven. Moreover, the complete surrounding portion cannot be formed at the edge of the connecting plate, and the connecting hole A and the central flowing water hole cannot be opened, resulting in waste of the connecting plate area. The above optimization can make the material distribution at the edge of the connecting plate uniform, and also make full use of the area of the edge of the connecting plate to enlarge the flow area ratio.

As a fifth optimization scheme of the present invention, on the basis of the above aspect, the flow holes A and the flow holes B are perpendicular to the axis. Under this structure, the surrounding portion is substantially square, and a circular connecting hole, a connecting hole B or a central flowing water hole is formed thereon, so that the area of the surrounding portion can be fully utilized, and the connecting plate is minimized. The waste of area maximizes the proportion of circulation area.

As a further optimization of the fifth optimization scheme of the present invention, the connecting plate is square, the axis of the water flow hole A is parallel to a diagonal line of the connecting plate, and the axis of the water flowing hole B is The other diagonal of the connecting plate is parallel. It can be seen that by this arrangement, the most flow holes can be arranged on the connecting plate, especially at the positions near the four corners of the connecting plate, the number of the flow holes can be increased, and the flow area ratio can be increased.

In summary, the advantages and benefits of the present invention are:

1. The invention can change the arrangement of the flow holes so that the flow holes can be evenly arranged, and at the same time increase the proportion of the flow area, and solve the technical problem that the upper tube seat is not economically good and the flow field distribution at the outlet of the fuel assembly is unfavorable;

2. The invention improves the flow area ratio by changing the shape of the flow hole, and at the same time, ensures the structural strength of the connecting plate;

3. By staggering the connection hole A and the central flow hole, the flow rate of the cooling water flowing out from the connection plate tends to be uniform, and the influence of the flow field distribution on the outlet of the fuel assembly is further reduced. DRAWINGS

In order to more clearly illustrate the embodiments of the present invention, a brief description of the drawings to be used in the embodiments of the present invention will be briefly described. It is obvious that the drawings in the following description are only some of the embodiments described in the present invention, and those skilled in the art can obtain other drawings according to the following drawings without any creative work. .

Figure 1 is a schematic view showing the structure of a nuclear fuel assembly;

2 is a schematic structural view of a connecting plate in a pipe socket of a conventional fuel assembly;

Figure 3 is a schematic cross-sectional view of the present invention;

Figure 4 is a schematic view showing a manner of opening a connecting plate of the present invention;

Figure 5 is a schematic view showing another opening mode of the connecting plate of the present invention;

Figure 6 is a plan view of the present invention;

The name of the component corresponding to the reference symbol is as follows:

1-Upper header, 2-connector, 3-socket, 4-frame, 5-connection hole A, 6-connection hole B, 7-positioning pin hole, 8-pin screw hole, 9-anti-dislocation Hole, 10-lifting surface, 201-flow hole A, 202-flow hole B, 203-joint, 204-fitting, 205-center water hole, 206-circular surface A, 207-circular surface B, 208 - lobe, 209 - flow hole C, 210 - flow hole D, 211 - flow hole E, 212 - side A, 213 - side B,, 214 - vacant.

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the drawings in the embodiments of the present invention. It will be apparent that the embodiments described below are only some, but not all, of the embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without departing from the scope of the invention are within the scope of the invention.

The "axis" of the flow hole refers to the center line passing through the ends of the flow hole, and the term "axial" refers to the flow hole. The direction of the axis, the term "radial" refers to the direction perpendicular to the axis of the flow hole. The flow hole includes a flow hole A201 and a flow hole B202 having the same size and shape. The size and shape of the flow hole C209, the flow hole D210, and the flow hole E211 are different from the flow hole A201 and the flow hole B202 in some cases, and thus are not included in the flowing water. In the range indicated by the hole.

Example

As shown in FIG. 3 and FIG. 4, the upper block of the fuel assembly is mainly composed of a connecting plate 2, a supporting plate 3 fixed to the edge of the connecting plate 2, and a frame plate 4 fixed to the surrounding plate 3. The connecting plate 2 is provided with useful a connecting hole A5 for mounting the fuel assembly guide tube and a connecting hole B6 for mounting the instrument tube, and a plurality of elongated water-flow holes are uniformly formed on the connecting plate 2, and the water-flow hole includes a water-flow hole A201 and a water-flow hole B202. An angle greater than 0° exists between the axis of the flow hole A201 and the flow hole B202. On the connecting plate 2, a connecting portion 203 is formed between the two axially adjacent water holes A201 and the two water holes B202. a connecting portion 204 is formed between the two adjacent water-flow holes A201 and the two water-flow holes B202 on the connecting plate 2; the connecting plate 2 is further provided with a central flow hole 205, the connecting hole A5, The connection hole B6 and the center flow hole 205 are respectively disposed on the surrounding portion 204.

The flow holes are used to pass the cooling water. Increasing the area of the flow hole can increase the proportion of the flow area on the connecting plate 2, thereby reducing the pressure drop on both sides of the connecting plate 2, consuming less main pump lift, and improving economy. The flow holes are arranged as evenly as possible to prevent lateral flow when the cooling water is distributed after passing through the upper pipe seat, thereby reducing the risk of failure of the control rod and the combustible poison rod due to vibration abrasion. In order to achieve the above object, the water holes are arranged in an intersecting manner. It can be seen that in this way, as long as the structural strength of the connecting plate 2 is ensured, as many flow holes as possible can be provided, thereby increasing the proportion of the flow area, reducing the pressure drop, and improving the economy. Moreover, this arrangement enables uniform distribution of the flow holes, so that the cooling water does not generate lateral flow when it is redistributed through the upper header, thereby reducing the control rod and the combustible poison. The risk of failure of the rod due to vibrational abrasion.

The above is only a general concept of the present invention. In the actual operation, under the premise of ensuring the structural strength of the connecting plate 2, the connecting portion 203 can be as small as possible to increase the flow area ratio. The change of the angle between the flow hole A201 and the flow hole B202 can change the area and shape of the surrounding portion 204, and ensure the structural strength of the connecting plate 2, and ensure that the connecting hole A5, the connecting hole B6 and the central flow hole 205 can be smoothly opened. The area of the surrounding portion 204 can also be as small as possible to increase the flow area ratio.

Example 2:

In the present embodiment, on the basis of the first embodiment, in order to further increase the flow area ratio, it is preferable that the shape of the flow hole is a rectangle. It will be understood by those skilled in the art that the rectangular flow holes can make the connection holes A5 and the connection holes B6 closest to the flow holes, thereby increasing the proportion of the flow area on the plate 2.

Example 3:

In the embodiment, on the basis of the first embodiment, as shown in FIG. 4, the side surface of the water pipe is concavely formed with a circular arc surface A206, and the arc of the circular arc surface A206 is adjacent to the adjacent connecting hole A5, the connecting hole B6 or the center. The arc of the flow hole 205 is matched. It can be understood by those skilled in the art that the arc surface A206 can be arranged to make the material distribution between the water injection hole and the connection hole A5, the connection hole B6 or the central flow hole 205 more uniform, and there is no weak part, and the ratio of the flow area is balanced. At the same time, the influence on the structural strength of the connecting plate 2 can also be reduced. On the basis of ensuring the structural strength of the connecting plate 2, the distance between the circular arc surface A206 and the connecting hole A5, the connecting hole B6 or the central flowing water hole 205 can be as small as possible.

Example 4:

In the embodiment, on the basis of the third embodiment, as shown in FIG. 4, the end surface of the flow hole is convexly formed to form a circular arc surface B207. It will be understood by those skilled in the art that the above improvements cause the flow holes to form in the middle. The narrow width and smooth edge structure increases the proportion of the flow area and at the same time relieves the stress concentration at the edge of the flow hole. By calculation, the flow area ratio of the present embodiment is increased by 6.5% with respect to the existing upper header.

Example 5

In the embodiment, on the basis of the third embodiment, as shown in Fig. 5, the end faces of the water holes are convexly formed into lobes 208 having straight lines on both sides. It can be seen that this optimization also increases the flow area ratio, and the lobes 208 have a longer extendable length in the axial direction. It should be noted that the top of the lobe 208 may be a circular arc shape, or may be a straight angle or other shape. The shape of the top of the lobes 208 is mainly selected according to the physical properties of the materials constituting the connecting plate 2. For materials having better stress concentration resistance, a straight angle can be preferentially selected to obtain a longer extending length.

Example 6:

This embodiment is based on the fifth embodiment. As shown in Fig. 5, adjacent sides of the adjacent ribs 208 are parallel. In order to clarify the optimization more clearly, in FIG. 5, two adjacent flow holes are selected, the two sides of the water holes are parallel to the nearest side A212 and the side B213, and the material between the side A212 and the side B213 is elongated. The distribution is uniform, and the distribution of the materials on the connecting plate 2 is more uniform and uniform as a whole, and the structural strength of the connecting plate 2 is improved. It can be seen that in this case, it is possible to enlarge the area of the flow hole so that the strength of the connecting plate is close to the acceptable bottom line, thereby obtaining the maximum flow area ratio.

Example 7

The present embodiment is based on the above embodiment. As shown in FIG. 4 and FIG. 5, the connecting hole A5 and the central water flowing hole 205 are alternately arranged, and the connecting hole B6 is opened at the center of the connecting plate 2. On the enclosure 204. The staggered arrangement indicates that the circumference of the central flow hole 205 is the connection hole A5, At the same time, the circumference of the connection hole A5 is the center flow hole 205. This optimization can make the flow rate of the cooling water flowing out of the connecting plate 2 tend to be uniform, and further reduces the influence on the flow field distribution at the outlet of the fuel assembly.

Example 8;

The embodiment is based on the above embodiment. As shown in FIG. 4 and FIG. 5, the connecting plate 2 is further provided with a water flowing hole C209, a water flowing hole D210 and a water flowing hole E211. The water flowing hole C209 is a circular hole or a circle. An angled rectangular hole, a flow hole C209 is disposed at four corners of the connecting plate 2 and arranged in a rectangular array, and the water flowing hole D210 and the water flowing hole E211 are long holes with outer convex arcs at both ends, and the length of the water flowing hole E211 is shorter than The length of the flow hole D210, the flow hole D210 and the flow hole E211 are provided at the edge of the connecting plate 2.

As can be seen from Figures 4 and 5, the web 2 is square, and if the water holes are also arranged at the edges thereof in a crosswise manner, the material distribution at the edges will be uneven. Moreover, the complete surrounding portion 204 cannot be formed at the edge of the connecting plate 2, so that the connecting hole A5 and the center water flowing hole 205 cannot be opened, resulting in waste of the area of the connecting plate 2. The above optimization can make the material distribution at the edge of the connecting plate 2 uniform, and also make full use of the area of the edge of the connecting plate 2, so that the flow area ratio can be enlarged.

The arrangement of the flow hole D210 and the flow hole E211 is as shown in Figs. 4 and 5. The connecting hole A5 at the edge of the connecting plate 2 occupies a large space, so a short water hole E211 is provided near the connecting hole A5. At the position between the two connection holes A5 at the edge of the connecting plate 2, the flow hole A201 and the flow hole B202 are replaced by the water holes D210 to obtain the maximum flow area ratio.

Further, it is preferable that the axis of the flow hole D210 and the flow hole E211 are parallel to the central axis of the connecting plate 2, and the side of the flow hole D210 and the flow hole E211 are parallel.

At a position close to the four corners of the connecting plate 2, the water flowing hole A201 and the water flowing hole B202 are eliminated, and the vacant portion 214 is obtained, and the vacant portion 214 is filled with the two central water flowing holes 205 and one connecting hole A5. The extra space, this arrangement not only achieves the largest proportion of the flow area, but also makes it easier to arrange the water hole D210 and the water hole E211 at the edge of the connecting plate 2.

Example 9

The present embodiment is based on the above embodiment. As shown in Figs. 4 and 5, the flow holes A201 and the flow holes B202 are perpendicular to the axis. In this configuration, the surrounding portion 204 is substantially square, and a circular connecting hole A5, a connecting hole B6 or a central water flowing hole 205 is formed thereon, so that the area of the surrounding portion 204 can be fully utilized, and the width is minimized. The waste of the area of the connecting plate 2 maximizes the proportion of the flow area.

Example 10

The embodiment is based on Embodiment 9, as shown in FIG. 4 and FIG. 5, the connecting plate 2 is square, and the axis of the water flowing hole A201 is parallel to a diagonal line of the connecting plate 2, The axis of the flow hole B202 is parallel to the other diagonal line of the connecting plate 2. It can be seen that by this arrangement, the largest number of water holes can be arranged on the connecting plate 2, especially at a position close to the four corners of the connecting plate 2, the number of the water holes can be increased, and the flow area ratio can be increased.

Example 11:

The upper assembly of the fuel assembly is mainly composed of a square connecting plate 2, a surrounding plate 3 fixed to the edge of the connecting plate 2, and a frame plate 4 fixed to the surrounding plate 3. The connecting plate 2 is provided with a connection for mounting the fuel assembly guiding tube. The hole A5 and the connecting hole B6 for mounting the instrument tube are uniformly provided with a plurality of flowing water holes integrally formed on the connecting plate 2, and the water flowing holes include a water flowing hole A201 and a water flowing hole B202, and the water flowing hole A201 and There is an angle greater than 0° between the axes of the flow holes B202; on the connecting plate 2, a connecting portion 203 is formed between the two axially adjacent water holes A201 and the two water holes B202; On the plate 2, between the two radially adjacent water holes A201 and the two water holes B202 The connecting plate 2 is further provided with a central flow hole 205, and the connecting hole A5, the connecting hole B6 and the central flowing water hole 205 are respectively disposed on the surrounding portion 204. The flow hole A201 is perpendicular to the axis of the flow hole B202, the axis of the flow hole A201 is parallel to a diagonal line of the connecting plate 2, and the axis of the flow hole B202 is different from the connecting plate 2 One diagonal is parallel. The side surface of the water flow hole is concavely formed to form a circular arc surface A206, and the curvature of the circular arc surface A206 matches the curvature of the adjacent connection hole A5, the connection hole B6 or the central flow hole 205. The end faces of the flow holes are convexly formed to form lobes 208 having straight lines on both sides. Adjacent sides of the lobes 208 are adjacent to each other. The connecting plate 2 is further provided with a water flowing hole C209, a water flowing hole D210 and a water flowing hole E211. The water flowing hole C209 is a circular hole or a rounded rectangular hole, and the water flowing hole C209 is disposed at four corners of the connecting plate 2 and arranged in a rectangular array. Arrangement, the water flow hole D210 and the water flow hole E211 are long holes with outer convex arcs at both ends, the length of the water flow hole E211 is shorter than the length of the water flow hole D210, and the water flow hole D210 and the water flow hole E211 are disposed at the edge of the connection plate 2 .

The flow area of this embodiment is increased by 7.8% with respect to the existing upper header.

Example 12:

This embodiment is based on the above embodiment, as shown in FIG. 3 and FIG. 6, positioning pin holes 7 are provided on two opposite corners of the frame plate 4, so that the present invention can be used with the positioning pin of the upper core plate. Cooperate. On the other two opposite corners of the upper end surface of the frame plate 4 are respectively provided with pressing screw holes 8 for mounting the leaf springs to achieve axial compression of the fuel assembly. The upper end surface of the frame plate 4 is further provided with an anti-missing hole 9 which is located at any corner where the pressing screw hole 8 is provided for identifying the orientation of the component in the core and is compatible with the lifting tool. The number of the positioning pin hole 7, the pressing screw hole 8 and the misalignment preventing hole 9 and the setting position are not limited thereto, and may be separately designed according to actual conditions, for example: the number of positioning pin holes 7 and the setting position according to the positioning of the upper core plate The number of pins and the location are set as long as their position is met and The pin can be matched. The interior of the frame plate 4 is provided with a lifting surface 10 for facilitating the lifting of the fuel assembly. In order to make the present invention more clearly understood by those skilled in the art, the processing of the present invention will now be described.

First, respectively processing the connecting plate 2, the surrounding plate 3 and the frame plate 4;

Then, the panel 3 is placed on the upper end surface of the connecting plate 2, and then the frame plate 4 is placed on the upper end surface of the panel 3, and is fixed by the fixture;

Finally, the connecting plate 2, the surrounding plate 3 and the frame plate 4 are welded integrally.

Those skilled in the art will appreciate that many variations and configurations of the various exemplary embodiments described above can be applied selectively to form other possible embodiments of the present invention. All possible combinations and possible embodiments are not provided or described in detail herein, in view of the abilities of those skilled in the art, but all combinations and possible embodiments that are included in other forms are part of this application.

Claims

Rights request

1. The upper pipe seat of the fuel assembly is mainly composed of a connecting plate (2), a coaming plate (3) fixed on the edge of the connecting plate (2), and a frame plate (4) fixed on the coaming plate (3). The connecting plate ( 2) is provided with a connection hole A (5) for installing the fuel assembly guide pipe and a connection hole B (6) for installing the instrument pipe. It is characterized in that: there are multiple holes evenly provided on the connecting plate (2). An elongated water hole, the water hole includes a water hole A (201) and a water hole B (202), and there is an angle greater than 0° between the axes of the water hole A (201) and the water hole B (202);

On the connecting plate (2), a connecting portion (203) is formed between two axially adjacent water holes A (201) and two water holes B (202); on the connecting plate (2) , an enclosed portion (204) is formed between the two radially adjacent water holes A (201) and the two water holes B (202);

The connecting plate (2) is also provided with a central drain hole (205), and the connecting hole A (5), the connecting hole B (6) and the central drain hole (205) are respectively provided on the enclosing portion (204).

2. The fuel assembly upper tube holder according to claim 1, characterized in that: the water flow hole is rectangular.

3. The fuel assembly upper tube holder according to claim 1, characterized in that: the side surface of the water flow hole is concave to form an arc surface A (206), and the curvature of the arc surface A (206) is connected with the adjacent Match the curvature of hole A (5), connecting hole B (6) or central drain hole (205).

4. The fuel assembly upper tube holder according to claim 3, characterized in that: the end surface of the water flow hole is convex to form an arc surface B (207).

5. The fuel assembly upper tube holder according to claim 3, characterized in that: the end surface of the water flow hole is convex to form a straight convex angle (208) on both sides.

6. The fuel assembly upper tube holder according to claim 5, characterized in that: the adjacent The adjacent sides of the lobe (208) are parallel.

7. The upper tube holder of the fuel assembly according to claim 1, characterized in that: the connecting hole A (5) and the central water hole (205) are arranged in a staggered manner, and the connecting hole B (6) is opened at On the enclosing portion (204) at the center of the connecting plate (2).

8. The fuel assembly upper tube holder according to claim 1, characterized in that: the connecting plate

(2) is also provided with drain hole C (209), drain hole D (210) and drain hole E (211). Drain hole C (209) is a circular hole or a rounded rectangular hole. Drain hole C (209) They are arranged at the four corners of the connecting plate (2) and arranged in a rectangular array. The drain hole D (210) and the drain hole E (211) are long holes with convex arcs at both ends. The drain hole E (211) The length of is shorter than the length of the drain hole D (210), and the drain hole D (210) and the drain hole E (211) are set at the edge of the connecting plate (2).

9. The fuel assembly upper tube holder according to any one of claims 1 to 8, characterized in that: the axes of the water flow hole A (201) and the water flow hole B (202) are perpendicular.

10. The fuel assembly upper tube holder according to claim 9, characterized in that: the connecting plate (2) is square, and the axis of the water hole A (201) is aligned with one of the connecting plates (2). The diagonals are parallel, and the axis of the water hole B (202) is parallel to the other diagonal of the connecting plate (2).