KR101062786B1 - Support grid of nuclear fuel rods - Google Patents

Abstract

The present invention relates to a support lattice of a nuclear fuel rod, and a technical problem to be solved is to provide a support lattice of a nuclear fuel rod capable of supporting not only a conventional nuclear fuel rod but also a dual-cooled nuclear fuel rod having a large diameter.

To this end, the support grid of the nuclear fuel rod according to the present invention is continuously formed with a curved spring formed in the center of the first insertion slot portion vertically cut at one end in the longitudinal direction, by the planar portion located between the curved springs A first inner grating plate having integrally connected curved springs and having dimples supporting nuclear fuel rods on the planar portions disposed at both sides thereof; A plurality of curved springs having a second insertion slot portion formed in the center portion and a flat portion for integrally connecting the curved spring is formed, the first insertion slot portion, another second insertion slot portion or the A second inner grating plate having a slot orthogonally coupled to a third insertion slot portion and a dimple supporting the nuclear fuel rod; A curved grating plate having a plurality of curved springs having a third insertion slot portion formed at a central portion thereof, and a flat portion for integrally connecting the curved springs with slots which are orthogonally coupled to the second insertion slot portions at the flat portions disposed at both sides; And a third internal grating plate having a flat grating plate disposed at both sides of the curved grating plate at predetermined intervals and having a slot orthogonally coupled to the first insertion slot unit or the second insertion slot unit and a dimple supporting the nuclear fuel rod. ; A fourth inner part spaced apart from each other by a predetermined distance from the center part and having a slot orthogonally coupled to the first insertion slot part, the second insertion part or the third insertion slot part, and a dimple supporting the nuclear fuel rod; Gratings; And an outer grating plate to which both ends of the first inner grating plate and the fourth inner grating plate are welded and fixed, respectively, wherein the curved spring is disposed at an edge portion of the nuclear fuel rod cell formed by the first inner grating plate and the fourth inner grating plate. The two curved springs are curved into the fuel rod cell to support the fuel rod.

Internal grating, curved springs, flats, dimples, insertion slots

Description

SPACER GRID FOR NUCLEAR FUEL RODS}

The present invention relates to a support grid of a nuclear fuel rod and to a support grid of a nuclear fuel rod capable of supporting a large nuclear fuel rod.

Figure 16 is a perspective view schematically showing a fuel assembly according to the prior art, Figure 17 is a plan sectional view schematically showing a cross-section of the fuel assembly according to the prior art, Figure 18 is a support grid applied to the fuel assembly according to the prior art 19 is a plan view schematically illustrating a portion of the structure, FIG. 19 is a perspective view schematically illustrating a portion of a support grid applied to a nuclear fuel assembly according to the prior art, and FIG. 20 is a unit of the support grid supporting the fuel rod according to the prior art. It is a perspective view which shows a grid board schematically.

As shown in the figure, the fuel assembly 100 is composed of a nuclear fuel rod 110, the guide tube 140, the support grid 150, the upper fixture 120 and the lower fixture 130.

Here, the nuclear fuel rod 110 includes a cylindrical uranium sintered body in the zirconium alloy cladding tube, the high temperature heat is generated by the nuclear fission reaction of the uranium sintered body.

On the other hand, the guide tube 140 is used as a passage of the control rod to move up and down in order to control the output of the reactor core and to stop the fission reaction, the support grid 150 is supported by one of the components of the fuel assembly Springs 118 and dimples 119 in their respective grids have a function of supporting the nuclear fuel rods 110 to be arranged at a predetermined position.

The upper fixture 120 and the lower fixture 130 serve to fix and support the nuclear fuel assembly 100 in the upper and lower structures of the core, and the lower fixture 130 filters foreign substances floating in the core. It includes a filtration device (not shown) for.

In addition, the support grid 150 is usually made of a zirconium alloy, and there are guide rod cells into which the nuclear fuel rod cell and the guide tube 140 are inserted to support the nuclear fuel rods 110. 2 grid springs 118 one by one and the top and bottom of the springs, and two dimples 119 each of the two on each of the other two sides to support the nuclear fuel rod 110 at a total of six support points have.

In addition, the nuclear fuel rod 110 is charged with a cylindrical uranium dioxide sintered body, and the coolant is surrounded by four nuclear fuel rods 110, or is surrounded by three nuclear fuel rods 110 and one guide tube 140. It flows rapidly from the bottom of the core to the top in the axial direction through the sub channel 115. Here, the sub-channel 115 refers to a space enclosed by the nuclear fuel rods 110 and has a side that is open and refers to a passage through which fluid can freely move to a neighboring flow path.

On the other hand, when the spring force of the grid spring 118 located in the limited space, that is, the spring constant is too small, the nuclear fuel rod 110 can not be supported in a predetermined position, and thus the support integrity of the nuclear fuel rod 110 may be lost. have.

On the contrary, when the spring force of the grid spring 118 is too large, a flaw such as a scratch on the surface of the nuclear fuel rod 110 due to excessive frictional resistance when the nuclear fuel rod 110 is inserted into the support grid 150. It may occur, the fuel rod 110 is bent due to the longitudinal growth and thermal expansion of the nuclear fuel rod 110 due to neutron irradiation during the operation of the reactor, that is, the bending of the nuclear fuel rod 110 (Bowing) May cause.

When the fuel rod 110 is bent, the fuel rod 110 comes into contact with or comes into contact with adjacent fuel rods, thereby narrowing or blocking the coolant flow path between the fuel rods, that is, the sub-channel 115, which does not effectively transfer heat generated from the fuel to the coolant. As a result, the temperature of the nuclear fuel rods increases locally, leading to a decrease in the output of nuclear fuel.Departure from Nuclear Boiling DNB) is more likely to occur.

In addition, the flow of the reactor coolant flowing around the nuclear fuel rod 110 is a large turbulent flow, i.e., a high Reynolds number flow, in the coolant flow around the nuclear fuel rod 110 to improve thermal performance. It is commonly known that turbulence in the flow of coolant flow around a nuclear fuel rod is the main cause of flow induced vibration. The vibration of the fuel rod, which is the fluidizer of the nuclear fuel rod, causes the relative movement of the nuclear fuel rod 110 in the contact surface of the support grid 150 with the spring structure, thereby causing local wear on the contact surface of the fuel rod and the spring structure. This results in fretting wear damage of the fuel rod, which causes the fuel rod to be progressively damaged.

The support grid according to the prior art as described above has tried to make the appropriate spring force act on the nuclear fuel rod by variously changing the structure of the lattice spring, as shown in Figure 20 a plurality of units forming the support grid in most cases The lattice plate was pressed to form a grid spring integrally formed on the unit grid.

However, when the lattice spring protruding through the press working as described above is integrally formed on the unit grid, an empty space is inevitably created in a part of the unit grid. Such empty spaces make it impossible to transfer the support grids to adjacent unit grids when they are impacted on the sides. In other words, this means that the effective lattice height of the support grid itself against the side impact drops considerably after press working.

If the lateral strength of the support grid falls, the structural health may be seriously threatened when an earthquake with transverse characteristics occurs, and if the height of the support grid is increased to reinforce the lateral strength, This causes a problem of hydraulic losses in the coolant flow inside the reactor passing through the support grid.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a support grid of a nuclear fuel rod capable of supporting not only a conventional nuclear fuel rod but also a double-cooled nuclear fuel rod having a large diameter.

In addition, another object of the present invention is to provide a support grid of the nuclear fuel rod, the shape of the internal grating plate is simple and easy to mold design and manufacturing.

In addition, another object of the present invention is to provide a support grid of a nuclear fuel rod that can accommodate a guide tube having a large outer diameter.

In order to achieve the object as described above, the support grid of the nuclear fuel rod according to the present invention has a continuous curved spring formed in the center portion of the first insertion slot section vertically cut at one end in the longitudinal direction, between the curved springs A first inner grating plate in which the curved springs are integrally connected to each other by a located plane portion, and a dimple supporting a nuclear fuel rod is formed in the plane portions disposed at both sides; A plurality of curved springs having a second insertion slot portion formed in the center portion and a flat portion for integrally connecting the curved spring is formed, the first insertion slot portion, another second insertion slot portion or the A second inner grating plate having a slot orthogonally coupled to a third insertion slot portion and a dimple supporting the nuclear fuel rod; A curved grating plate having a plurality of curved springs having a third insertion slot portion formed at a central portion thereof, and a flat portion for integrally connecting the curved springs with slots which are orthogonally coupled to the second insertion slot portions at the flat portions disposed at both sides; And a third internal grating plate having a flat grating plate disposed at both sides of the curved grating plate at predetermined intervals and having a slot orthogonally coupled to the first insertion slot unit or the second insertion slot unit and a dimple supporting the nuclear fuel rod. ; A fourth inner part spaced apart from each other by a predetermined distance from the center part and having a slot orthogonally coupled to the first insertion slot part, the second insertion part or the third insertion slot part, and a dimple supporting the nuclear fuel rod; Gratings; And an outer grating plate to which both ends of the first inner grating plate and the fourth inner grating plate are welded and fixed, respectively, wherein the curved spring is disposed at an edge portion of the nuclear fuel rod cell formed by the first inner grating plate and the fourth inner grating plate. The two curved springs are curved into the fuel rod cell to support the fuel rod.

In addition, one end of the flat grating plate and one end of the fourth internal grating plate of the third internal grating plate may be disposed on the second insertion slot part of the second internal grating plate to form the guide tube cell.

In addition, the nuclear fuel rod cell may be formed with at least one dimple supporting the nuclear fuel rod.

In addition, one end of the flat grating plate and one end of the fourth inner grating plate of the third inner grating plate may be disposed on the second insertion slot part of the second inner grating plate, thereby forming the guide tube cell.

In addition, the dimples may be formed in pairs of two at upper and lower portions of the inner grating.

In addition, the dimple may have a trapezoidal shape.

In addition, the dimple may be formed in an arc shape.

In addition, the dimple may have a concave curvature corresponding to the curvature of the nuclear fuel rods.

In addition, the curved spring may be formed in an arc shape curved toward the center.

In addition, the curved spring may be formed by rounding one side of the corner into which the nuclear fuel rod is inserted or rounding both sides of the corner.

In addition, the curved spring may have a closed slot portion (closed slot) for adjusting the spring stiffness on both sides with respect to the central portion.

In addition, the nuclear fuel rods may be a dual cooling nuclear fuel rods.

In addition, the outer lattice plate may be continuously formed with a spring for supporting the nuclear fuel rods on one surface.

As described above, according to the support grid of the nuclear fuel rod according to the present invention, there is an effect capable of supporting not only a conventional nuclear fuel rod but also a dual-cooled nuclear fuel rod having a large diameter.

In addition, since the shape of the internal grating is simple, it is easy to design and manufacture the mold.

In addition, there is an effect that can accommodate a large guide tube outer diameter.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that the same components or parts in the drawings represent the same reference numerals as much as possible. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order not to obscure the gist of the present invention.

1 is a schematic plan view of a support grid of a nuclear fuel rod according to an embodiment of the present invention.

As shown in FIG. 1, the support grid of the nuclear fuel rod according to the embodiment of the present invention forms a 12 × 12 type support grid, and includes a first inner grating 10 and a second inner grating 20, 21. 22,23,24,25,26, third inner grating plate 40,40 ', fourth inner grating plate 50 and first inner grating plate 10 to fourth inner grating plate 50 Both ends of the to include an outer grating 60 to be welded to cover the first inner grating (10) to the fourth inner grating 50 (50).

2A is a perspective view of a first inner grating according to an embodiment of the present invention, and FIG. 2B is a partially enlarged view of FIG. 2A.

The first inner grating plate 10 elastically supports the nuclear fuel rod 70 inserted into the support grid 1, and as shown in FIGS. 2A and 2B, a plurality of curved springs 11 and the curved surface It includes a plurality of planar portions 12 for connecting the spring (11). In this case, the nuclear fuel rod 70 may be a double-cooled nuclear fuel rod having a large diameter.

The curved spring 11 is a portion where direct contact with the nuclear fuel rod 70 is formed. The curved spring 11 is continuously formed between the planar portions 12 of the first inner grating 10 and alternates in a curved direction. Is formed.

Therefore, the first inner grating 10 may elastically support the plurality of nuclear fuel rods 70 by the curved spring 11.

The curved spring 11 may be formed in an arc shape that is curved toward the center, and one side of the corner where the nuclear fuel rod 70 is inserted may be rounded, or both sides of the corner may be rounded.

Accordingly, when the nuclear fuel rod 70 is charged into the support grid 1, the surface of the nuclear fuel rod 70 may be prevented from being scratched, or the nuclear fuel rod 70 may be stably supported. The possibility of fretting wear damage due to vibration, which is the fluidizer of the nuclear fuel rod 70 due to the coolant flow, can be reduced, and the pressure resistance of the coolant passing through the support grid 1 can be reduced.

The curved spring 11 is formed with a first insertion slot 13 which is vertically cut at one end in the longitudinal direction at the center thereof.

As shown in FIG. 1, the first insertion slot 13 may be a slot of the second inner grating 20, 22, 24, and 26, a slot of the third inner grating 40, or the like. The first inner grating 10 and the second inner grating 20, 22, 24, 26, the first inner grating 10 and the third inner grating ( 40 ') and orthogonal coupling of the first inner grating 10 and the fourth inner grating 50 is induced.

3A is a perspective view of a first inner grating according to another embodiment of the present invention, and FIG. 3B is a partially enlarged view of FIG. 3A.

Meanwhile, as illustrated in FIGS. 3A and 3B, the curved spring 11 may have a closed slot 15 for adjusting spring stiffness on both sides of the center portion.

The closed slot 15 has a rectangular space to adjust the spring stiffness.

The planar portion 12 connects the curved springs 11 having different bending directions, and the planar portions 12 disposed on both sides of the first inner grating plate 10 connect the nuclear fuel rod 70. Supporting dimples 14 may be formed.

15A is a partial cross-sectional view of a first inner grating according to an embodiment of the present invention, and FIG. 15B is a partial cross-sectional view of a first inner grating according to another embodiment of the present invention.

The dimples 14 may be formed in two pairs at upper and lower portions of the first inner grating 10.

In this case, the dimple 14 may be formed in a trapezoidal shape, as shown in FIG. 15A, and may be formed in an arc shape, as shown in FIG. 15B.

On the other hand, the dimple 14 may be formed to have a concave curvature corresponding to the curvature of the nuclear fuel rod 70, may be formed convex, it may be formed flat.

As shown in FIG. 1 to identify a specific position in which the first inner grating 10 is disposed on the supporting lattice 1, the first inner grating 10 forming the supporting lattice 1 is formed. ) To the fourth inner grating 50 and the outer grating 60 may correspond to the 13 × 13 matrix.

The first inner grating 10 is symmetrically arranged in rows 2 and 12 of the matrix.

4 to 10 are perspective views of a second inner grating according to an embodiment of the present invention.

As shown in FIG. 4, the second inner grating 20 includes a plurality of curved springs 31 and a plurality of planar portions 32 connecting the curved springs 31.

The curved springs 31 are continuously formed between the planar portions 32 of the second inner grating 20, and are alternately formed with different curved directions.

The curved spring 31 has the same structure and contents as the curved spring 11 of the first inner grating 10, and will be described later with other second inner gratings 21, 22, 23, 24, 25, The curved spring 31 formed on the 26 and the curved spring 41 formed on the third internal gratings 40 and 40 ′ also have the same structure and content as the curved spring 11 of the first internal grating 10. Do.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot part 33 includes a slot of another second inner grating 21, 23, and 25, a slot of the third inner grating 40, and a fourth inner grating ( A second inner grating 21, 23 and 25, the second inner grating 20 and the third inner grating 40, and the second inner grating 20 different from the second inner grating 20, Orthogonal coupling of the inner grating 20 and the fourth inner grating 50 is induced.

On the other hand, although the curved spring 31 is not shown, a closed slot portion (not shown) of a rectangular space for adjusting the spring stiffness may be formed on both sides of the center portion.

Hereinafter, the curved springs 31 formed on the other second inner gratings 21, 22, 23, 24, 25, and 26 and the curved springs 41 formed on the third inner gratings 40, 40 ′ are also referred to as the center portion. As such, a closed slot portion (not shown) of a rectangular space for adjusting spring stiffness may be formed.

The planar portion 32 connects the curved springs 31 having different bending directions, and the planar portions 32 disposed on both sides of the second inner grating 20 may be used to connect the nuclear fuel rod 70. Supporting dimples 34 may be formed. In this case, the dimple 34 has the same structure and contents as the dimple 14 formed on the first inner grating 10.

In addition, the planar portion 32 is provided with a slot 35 orthogonally coupled to the first insertion slot portion 13 of the first inner grating 10 between the curved spring 31 and the dimple 14. .

The slot 35 is vertically cut along the one end in the longitudinal direction to a length of about half of the height, is inserted into the first insertion slot portion 13 so that the upper and lower ends of the first insertion slot portion 13 Can be joined by welding.

As shown in FIG. 1, the second internal grating 20 is symmetrically disposed in two rows and twelve rows in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 5, the second inner grating plate 21 according to the exemplary embodiment of the present invention has a plurality of flat springs 31 and a plurality of flat parts connecting the curved springs 31 to each other. 32).

The curved springs 31 are formed between the planar portions 32 of the second inner grating plate 21, and a plurality of curved springs 31 having a different bending direction from the curved springs 31 formed at the center are formed at the center of the curved springs 31. It is formed symmetrically to the left and right relative to.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot 33 may include a slot of another second inner grating 26, a slot of the third inner grating 40 'and a fourth inner grating 50. Orthogonal.

The flat part 32 connects the curved spring 31, and the flat part 32 disposed on both sides of the second inner grating 21 may have a dimple for supporting the nuclear fuel rod 70. 34 can be formed in multiple numbers.

The dimple 34 has the same structure and contents as the dimple 14 formed in the first inner grating 10, and is shown in FIG. 1 between the curved spring 31 and the dimple 14 and between the dimples. As shown, slots orthogonally coupled to the second insertion slot portions of the other second inner gratings 20 and 22 are formed, respectively.

In addition, the planar portion 32 disposed between the curved springs 31 is provided with a slot orthogonally coupled with the slot formed in the planar portion of the other second inner grating 24.

As shown in FIG. 1, the second inner grating 21 is symmetrically arranged in rows 3 and 11 in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 6, the second inner grating plate 22 according to the exemplary embodiment may include a plurality of curved springs 31 and a plurality of planar portions connecting the curved springs 31. And (32).

The curved spring 31 is formed between the planar portions 32 of the second inner grating 22, and a plurality of curved springs 31 having the same curved direction are formed.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot 33 is orthogonally coupled to the slots of the other second inner gratings 21 and 25 and the third inner grating 40.

The flat part 32 connects the curved spring 31, and the flat part 32 disposed on both sides of the second inner grating plate 22 is a dimple supporting the nuclear fuel rod 70. 34) can be formed.

The dimple 34 has the same structure and contents as the dimple 14 formed in the first inner grating 10, and the flat portion 32 has the first insertion slot portion between the curved spring and the dimple. A slot orthogonally coupled to 13 is formed.

In addition, the planar portion 32 disposed between the curved springs 31 is orthogonally coupled to the slot formed in the planar portion of the second inner grating plate 23 and the slot formed in the planar portion of the fourth inner grating plate 50. Slot is formed.

As shown in FIG. 1, the second internal grating 22 is symmetrically arranged in three rows and eleven columns in a 13 × 13 matrix corresponding to the support grid.

Meanwhile, as shown in FIG. 7, the second inner grating plate 23 according to the exemplary embodiment may include a plurality of curved springs 31 and a plurality of planar portions connecting the curved springs 31. And (32).

The curved spring 31 is formed between the planar portions 32 of the second inner grating 23, and a plurality of curved springs 31 having different curved directions are formed.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot 33 may include a slot of another second inner grating 26, a slot of the third inner grating 40 'and a fourth inner grating 50. Orthogonal.

The flat part 32 connects the curved spring 31, and the flat part 32 disposed on both sides of the second inner grating plate 23 may have a dimple supporting the nuclear fuel rod 60. 34) can be formed.

The dimple 34 has the same structure and contents as the dimple 14 formed in the first inner grating 10, and has a second inner grating 20 different between the dimple 34 and the outer grating 60. A slot which is orthogonally coupled to the second insertion slot portion 33 of (), and is orthogonally coupled to the slot formed in the planar portion of the second inner grating plate 22 between the curved spring 31 and the dimple 34. Slots are formed.

In addition, the planar portion 32 disposed between the curved springs 31 is formed with a slot orthogonally coupled with a slot formed in the planar portion 32 of the other second inner grating 24.

As shown in FIG. 1, the second inner grating 23 is symmetrically arranged in rows 5 and 9 in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 8, another second inner grating 24 according to an embodiment of the present invention has a plurality of planar parts connecting the plurality of curved springs 31 and the curved springs 31. And (32).

The curved spring 31 is formed between the planar portions 36 of the second inner grating 24, each of which is formed with a plurality of curved springs 31 having the same curved direction at the center and near the center. A curved spring 31 having a different bending direction at a distance is formed.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot 33 is orthogonal to a slot of another second inner grating 25, a slot of the third inner grating 40, and a fourth inner grating 50. To combine.

The flat part 32 connects the curved spring 31, and the flat part 32 disposed on both sides of the second inner grating 24 has a dimple (not shown) that supports the nuclear fuel rod 70. 34 can be formed in multiple numbers.

The dimple 34 has the same structure and contents as the dimple 14 formed in the first inner grating 10, and a first insertion slot portion of the first inner grating 10 between the dimples 34. A slot that is orthogonally coupled to 13 is formed, and a slot that is orthogonally coupled to the slot formed in the planar portion of the second inner grating 21 between the curved spring 31 and the dimple 34 is formed.

In addition, the planar portion 32 disposed between the curved springs 31 is provided with a slot orthogonally coupled with the slot formed in the planar portion of the other second inner grating 23.

As shown in FIG. 1, the second internal grating 24 is symmetrically arranged in rows 5 and 9 in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 9, the second inner grating plate 25 according to the embodiment of the present invention has a curved spring 31 and a plurality of flat parts 32 connected to the curved spring 31. ).

The curved spring 31 is formed at the center of the second inner grating 25.

The curved spring 31 is formed with a second insertion slot portion 33 cut vertically at one end in the longitudinal direction at the center portion.

As shown in FIG. 1, the second insertion slot 33 is orthogonally coupled to the fourth inner grating 50.

The flat part 32 may be disposed at both sides of the second inner grating plate 25, and a dimple 34 supporting the nuclear fuel rod 70 may be formed.

The dimple 34 has the same structure and contents as the dimple 14 formed in the first inner grating 10, and the second inner grating 20, which is different between the dimple 34 and the curved spring 31. Slots that are orthogonally coupled to the second insertion slot portions 22, 24, and 26 and the third insertion slot portions of the third internal grating 40 'are formed.

As shown in FIG. 1, the second internal grating 25 is symmetrically arranged in 6 rows and 8 rows in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 10, the second inner grating plate 26 according to the embodiment of the present invention has a plurality of planar parts connecting the plurality of curved springs 31 and the curved springs 31. And (32).

The curved spring 31 is formed between the planar portions 32 of the second inner grating plate 26, and a second insertion slot portion 33 cut vertically at one end in the longitudinal direction is formed at the center thereof.

As shown in FIG. 1, the second insertion slot 33 is orthogonally coupled to the slot of another second inner grating 25 and the fourth inner grating 50.

Dimples 34 supporting the nuclear fuel rod 60 may be formed in the planar portions 32 disposed at both sides of the second inner grating 26.

The dimple 34 has the same structure and content as the dimple 14 formed in the first inner grating 10, and the first inner lattice 10 between the dimple 34 and the curved spring 31. Slots that are orthogonally coupled to the first insertion slot portion of), the second insertion slot portion of the other second inner grating plates 21 and 23, and the third insertion slot portion of the third inner grating plate 40.

As shown in FIG. 1, the second internal grating 26 is symmetrically arranged in rows 6 and 8 in a 13 × 13 matrix corresponding to the support grid 1.

11 to 12 are perspective views of a third inner grating according to an embodiment of the present invention.

As illustrated in FIG. 11, the third internal grating 40 includes a curved grating 46, and planar gratings 47 disposed on both sides of the curved grating 46.

The curved grating plate 46 includes a plurality of curved springs 41 and a plurality of planar portions 42 for integrally connecting the curved springs 41.

The curved spring 41 is formed between the planar portions 36 of the curved grating 46, and a plurality of curved springs 41 having different curved directions are formed.

The curved spring 41 is formed with a third insertion slot portion 43 cut vertically at one end in the longitudinal direction at the center thereof.

As shown in FIG. 1, the third insertion slot portion 43 is orthogonally coupled to the slot of the second inner grating 26 and the slot of the fourth inner grating 50.

The planar portions 42 disposed on both sides of the curved grating 46 are orthogonally coupled to the second insertion slot 33 of the second inner grating 24.

The flat grating 47 is disposed at regular intervals on both sides of the curved grating 46, and slots 45 are orthogonally coupled to the first insertion slot 13 of the first internal grating 10. A dimple supporting the nuclear fuel rod 70 is formed and is orthogonally coupled to the second insertion slot portion 33 of the second inner grating 22.

As shown in FIG. 1, the third internal grating 40 is symmetrically arranged in four rows and ten rows in a 13 × 13 matrix corresponding to the support grid 1.

Meanwhile, as shown in FIG. 12, another third internal grating 40 'according to an embodiment of the present invention is a plane disposed on both sides of the curved grating 46 and the curved grating 46. Grating 47.

The curved grating 46 includes a plurality of curved springs 41 and a plurality of flat portions 42 which integrally connect the curved springs 41, and the curved springs 41 have the curved grating 46. A plurality of curved directions are formed in the same manner between the planar portions 42.

The curved spring 41 is formed with a third insertion slot portion 43 cut vertically at one end in the longitudinal direction at the center thereof.

As shown in FIG. 1, the third insertion slot portion 31 is orthogonally coupled to the slot of the second inner grating 25 and the slot of the fourth inner grating 50.

The planar portions 42 disposed on both sides of the curved grating 46 are orthogonally coupled to the second insertion slots of the second inner grating 23.

The flat grating 47 is disposed at regular intervals on both sides of the curved grating 46, and slots 45 are orthogonally coupled to the first insertion slot 13 of the first internal grating 10. A dimple 44 for supporting the nuclear fuel rod 70 is formed, and is orthogonally coupled to the second insertion slot 33 of the second inner grating 21.

As shown in FIG. 1, the third internal grating 40 'is disposed symmetrically in rows 4 and 10 in a 13 × 13 matrix corresponding to the support grid 1.

As shown in FIG. 1, the guide tube cell 80 formed by the second inner grating plates 21, 22, 23, and 24 and the third inner grating plates 40, 40 ′ is formed by the curved spring. The cell 80 is bent outwardly, and one end of the planar grating among the third inner gratings 40, 40 ′ is a second insertion slot of the second inner gratings 21, 22, 23, and 24. Disposed on and combined. Therefore, a guide tube with a large outer diameter can be accommodated.

13 is a perspective view of a fourth internal grating according to an embodiment of the present invention.

As shown in FIG. 13, the fourth inner grating 50 is spaced apart from both sides with respect to the center of the fourth inner grating 50, and the first insertion slot 13 of the first inner grating 10, and the Slots orthogonally coupled to the second insertion slot portion 33 of the second inner grating 20, 21, 22, 23, 24 and the third insertion slot portion 43 of the third inner grating 40, 40 '. A dimple supporting the nuclear fuel rod 55 is formed and orthogonally coupled to the second insertion slot 33 of the second inner grating 25 and 26.

As shown in FIG. 1, the fourth internal grating 50 is disposed in 7 rows and 7 columns in a 13 × 13 matrix corresponding to the support grid 1.

Slots of the fourth inner grating 50 arranged in the seventh row include second insertion slots of the second inner grating 20 and 24 and third insertion slots of the third inner grating 40 '. And a slot formed in the planar portion of the second inner grating 22.

In addition, a slot of the fourth inner grating plate 50 arranged in the seventh row may include a first insertion slot part of the first inner grating plate 10 and a second insertion slot part of the second inner grating plates 21 and 23. And a third insertion slot portion of the third inner grating 40.

As shown in FIG. 1, the guide tube cell 80 formed by the second inner grating plates 25 and 26 and the fourth inner grating plate 50 is curved to the outside of the guide tube cell 80. One end of the fourth inner grating 50 is disposed on and coupled to the second insertion slots of the second inner gratings 25 and 26.

14A is a side view of an external grating according to an embodiment of the present invention, and FIG. 14B is a cross-sectional view of the external grating according to an embodiment of the present invention.

As shown in FIGS. 14A and 14B, the outer grating 60 is continuously provided with springs 61 that support the nuclear fuel rod 70 on one surface thereof at equal intervals.

As illustrated in FIG. 1, the outer grating 60 is symmetrically arranged in rows 1 and 13, columns 1 and 13, respectively, in a 13 × 13 matrix corresponding to the support grid 1.

As shown in FIG. 1, the support grid 1 according to the present invention has the curved spring of the fuel rod cell formed by the first inner grating plate 10 to the fourth inner grating plate 50. Is disposed at the corner portion, the two curved springs are bent into the fuel rod cell, at least one dimple may be formed to support the fuel rod.

That is, the support grid 1 has a structure in which two curved springs are located at intersections in a direction intersected or diagonally connected to each other among four intersection regions formed by an internal grating plate, and a dimple supports the nuclear fuel rod 70. Can be formed.

As described above with reference to the drawings illustrating a support grid of the nuclear fuel rod according to the present invention, the present invention is not limited by the embodiments and drawings disclosed herein, those skilled in the art within the scope of the present invention Of course, various modifications may be made.

1 is a schematic plan view of a support grid of a nuclear fuel rod according to an embodiment of the present invention.

2A is a perspective view of a first inner grating according to one embodiment of the present invention.

FIG. 2B is an enlarged partial view of FIG. 2A; FIG.

3A is a perspective view of a first inner grating according to another embodiment of the present invention.

3B is an enlarged partial view of FIG. 3A.

4 to 10 are perspective views of a second inner grating according to an embodiment of the present invention.

11 to 12 are perspective views of a third inner grating according to an embodiment of the present invention.

13 is a perspective view of a fourth inner grating according to an embodiment of the present invention.

14A is a side view of an outer grating according to one embodiment of the present invention.

14B is a cross-sectional view of an outer grating according to one embodiment of the present invention.

15A is a partial cross-sectional view of a first inner grating according to one embodiment of the present invention.

15B is a partial cross-sectional view of the first inner grating according to another embodiment of the present invention.

Figure 16 is a perspective view schematically showing a nuclear fuel assembly according to the prior art.

17 is a plan sectional view schematically showing a cross section of a nuclear fuel assembly according to the prior art.

18 is a plan view schematically showing a part of a support grid applied to a nuclear fuel assembly according to the prior art;

19 is a perspective view schematically showing a part of a support grid applied to a nuclear fuel assembly according to the prior art;

20 is a perspective view schematically showing a unit grid of the support grid for supporting a nuclear fuel rod according to the prior art.

<Description of Symbols for Main Parts of Drawings>

1: support grid 10: first internal grating

11, 31, 41: curved spring 12, 32, 42: flat

13: first insertion slot 14, 34, 44, 54: dimple

15: closed slot

20,21,22,23,24,25,26: second internal grating

33: second insertion slot 35, 45, 55: slot

40,40 ': third internal grating

43: third insertion slot portion 46: curved grating

47: flat grating 50: fourth internal grating

60: Outer grating 61: Spring

70: nuclear fuel rod 80: guide cell

Claims (13)

A curved spring 11 having a centrally formed first insertion slot portion 13 vertically cut at one end in the longitudinal direction is continuously formed, and is provided by the planar portion 12 positioned between the curved springs 11. A first inner grating plate 10 in which the curved springs 11 are integrally connected, and dimples 14 supporting nuclear fuel rods 70 are formed in the planar portions 12 disposed at both sides; A plurality of curved springs 31 having a second insertion slot portion 33 formed in a central portion thereof and a flat portion 32 integrally connecting the curved springs 31 are formed, and the flat portions 32 disposed on both sides thereof. A slot 35 orthogonally coupled to the first insertion slot portion 13, another second insertion slot portion 33, or a third insertion slot portion 43 to be described later, and the nuclear fuel rod 70. Second inner gratings 20, 21, 22, 23, 24, 25, and 26 on which dimples 34 are formed; A plurality of curved springs 41 having a third insertion slot portion 43 formed in a central portion thereof and a flat portion 42 for integrally connecting the curved springs 41 are formed, and the flat portions 42 disposed on both sides thereof. Is spaced apart at regular intervals on both sides of the curved grating plate 46 and orthogonally coupled to the second insertion slot part 33, and the first insertion slot part 13 or the second insertion A third internal grating plate (40, 40 ') comprising a flat grating (47) formed with a slot (45) orthogonally coupled to the slot part (33) and a dimple (44) for supporting the nuclear fuel rod (70); A slot 55 spaced apart from each other on both sides of the central portion and orthogonally coupled to the first insertion slot portion 13, the second insertion slot portion 33, or the third insertion slot portion 43; A fourth internal grating plate 50 in which a dimple 54 supporting the nuclear fuel rod 70 is formed; And Including the outer grating 60 is fixed to both ends of the first inner grating plate to the fourth inner grating plate, respectively, The curved springs 11, 31, and 41 are disposed at corners of the nuclear fuel rod cells formed by the first to fourth inner grids, and two of the curved springs 11, 31, and 41 are inserted into the fuel rod cells. Curved support grid of the nuclear fuel rods, characterized in that for supporting the nuclear fuel rods (70). The method of claim 1, Guide tube cells formed by the second inner grating plate 21, 22, 23, 24 and the third inner grating plate 40, 40 ′ or the second inner grating plate 25, 26 and the fourth inner grating plate 50 ( 80 is a support grid of the nuclear fuel rod, characterized in that the curved spring 31 is formed by bending to the outside of the guide tube cell (80). 3. The method of claim 2, One end of the planar grating 47 of the third internal gratings 40 and 40 ′ is disposed on the second insertion slot 33 of the second internal gratings 21 and 22 to provide the guide tube cell 80. ) And one end of the fourth inner grating 50 is disposed on the second insertion slot 33 of the second inner grating 25 and 26 to form the guide tube cell 80. A support grid for a nuclear fuel rod. The method of claim 1, The fuel rod cell is a support grid of the nuclear fuel rod, characterized in that at least one dimple supporting the fuel rod is formed. The method of claim 1, The dimple is a support grid of the nuclear fuel rod, characterized in that formed in a pair consisting of two upper and lower portions of the first to fourth inner grating plate. The method of claim 1, The dimple is a support grid of the nuclear fuel rod, characterized in that the trapezoidal shape. The method of claim 1, The dimple is a support grid of the nuclear fuel rod, characterized in that formed in an arc shape. The method of claim 1, The dimple has a concave curvature corresponding to the curvature of the nuclear fuel rod support grid of the nuclear fuel rod. The method of claim 1, The curved spring (11,31,41) is a support grid of the nuclear fuel rod, characterized in that formed in an arc shape curved toward the center. The method of claim 1, The curved spring (11,31,41) is a support grid of the nuclear fuel rod, characterized in that one side of the corner is inserted into the nuclear fuel rod (70) is rounded, or both sides are rounded. The method of claim 1, The curved spring (11) is a support grid of the nuclear fuel rod, characterized in that the closed slot portion (15) is formed for adjusting the spring stiffness on both sides of the center portion. The method of claim 1, The nuclear fuel rod support grid of the nuclear fuel rods, characterized in that the dual-cooled nuclear fuel rods. The method of claim 1, The outer lattice plate 60 is a support grid of the nuclear fuel rod, characterized in that the spring 61 for supporting the nuclear fuel rod 70 on one surface continuously formed at equal intervals.

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