KR20090010443A - Support Grid of Dual Cooled Fuel Rod Using Cross Point Supports - Google Patents

Abstract

The present invention relates to a support grid for supporting Dual Cooling Nuclear Fuel Rods arranged at a narrow interval. The present invention relates to a dual cooling nuclear fuel rod for improving cooling performance and fuel stability and obtaining high combustion and high output. As the outer diameter of the nuclear fuel rods increases, the gap between the nuclear fuel rods and the lattice plate is narrowed to solve the problem that the conventional support grid cannot be used. The support grid of the dual-cooled fuel rods according to the present invention has a predetermined interval. It characterized in that it comprises a first grid plate and the second grid plate of the plate shape arranged to cross in the horizontal and vertical direction and the support is inserted in the vicinity of the intersection of the first grid plate and the second grid plate to support the dual-cooled fuel rods. .

Description

Space grid for dual cooling nuclear fuel rods by using a supporting structure at intersection}

The present invention relates to a support grid of a dual-cooled fuel rod under development in order to lower the center temperature of the nuclear fuel rod to secure the fuel rod safety and increase the output even at ultra-high combustion, and to obtain an economic effect. The present invention relates to a support grid for supporting a dual-cooled fuel rod in a diagonal direction by inserting a support at an intersection point of the support lattice in response to a narrower gap between the fuel rod and the support.

1 is a perspective view schematically showing a nuclear fuel assembly according to the prior art, Figure 2 is a plan sectional view schematically showing a cross section of the nuclear fuel assembly according to the prior art, Figure 3 is a support grid applied to the nuclear fuel assembly according to the prior art 4 is a perspective view schematically illustrating a support grid applied to a nuclear fuel assembly according to the prior art, and FIG. 5 schematically illustrates a unit grid of the support grid supporting a nuclear fuel rod according to the prior art. It is a perspective view showing.

As shown in the figure, the nuclear fuel assembly 100 is composed of a nuclear fuel rod 110, a guide tube 140, a 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 to control the output of the reactor core and to stop the fission reaction, the support grid 150 is supported as one of the components of the reactor fuel assembly A spring 118 and a dimple 119 in each lattice of the lattice body have a function of supporting the nuclear fuel rod 110 to be arranged at a predetermined position.

If the spring force in the spring 118 and the dimple 119 is too small, the fuel rod 110 may not be supported at a predetermined position, which may cause loss of support integrity of the nuclear fuel rod 110, and the spring force may be too large. In this case, when inserting the nuclear fuel rod 110 into the support grid itself, scratches such as scratches may occur on the surface of the nuclear fuel rod 110 due to excessive frictional resistance, and the length of the nuclear fuel rod 110 due to neutron irradiation during reactor operation. Inability to properly accommodate directional growth may cause the nuclear fuel rods 110 to bend, that is, to cause bowing of the nuclear fuel rods 110.

When the fuel rod 110 is bent, the fuel rod 110 is brought into close contact with or in contact with adjacent fuel rods 110 to narrow or block the coolant channel, that is, the sub-channel 115 between the fuel rods, which effectively prevents heat generated from the fuel. Because of this, the fuel rod temperature rises locally, causing the nuclear to escape from nuclear boiling. DNB) increases the likelihood of generating nuclear fuel, thereby reducing the fuel output.

The upper fixture 120 and the lower fixture 130 play a role of fixing and supporting the fuel assembly 100 in the upper and lower structures of the core, and the lower fixture 130 filters foreign matter floating in the core. Filtration device (foreign filter, not shown) for.

On the other hand, the support grid 150 is usually made of a zirconium alloy, there is a fuel rod cell for supporting the nuclear fuel rods 110 and the guide tube cells into which the guide tube 140 is inserted, one nuclear fuel rod cell each one in two sides A total of two grid springs 118 and the upper and lower sides of the springs, respectively, two drips 119 on each of the two remaining surfaces to support the nuclear fuel rod 110 at six support points.

Meanwhile, a cylindrical uranium dioxide sintered body is charged inside the nuclear fuel rod 110, and the coolant is surrounded by four nuclear fuel rods 110 or 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.

Meanwhile, as shown in FIGS. 6 and 7, dual-cooled nuclear fuel rods 10 having an annular structure instead of the cylindrical nuclear fuel rods 110 are disclosed in US Patent Nos. 3,928,132 and 6,909,765.

Here, the dual-cooled nuclear fuel rod 10 having an annular structure is composed of an sintered body 11 formed in an annular shape, an inner cladding tube 12 provided at an inner circumference, and an outer cladding tube 13 provided at an outer circumference thereof. Possibility of fuel damage by raising the central temperature of the fuel by maintaining the surface temperature of the dual-cooled fuel rod 10 by allowing heat to be transferred to the inside as well as the outside of the dual-cooled nuclear fuel rod 10 to maintain the surface temperature of the dual-cooled nuclear fuel rod 10 By lowering the safety margin of the dual-cooled nuclear fuel rod 10 to enable high combustion and high power.

However, in order to be structurally compatible with the existing pressurized water reactor-type core, the dual-cooled nuclear fuel rod 10 is located within the nuclear fuel assembly 100. The reason why the position of the guide tube 140 cannot be changed in order to maintain compatibility with the core structural components and the reason why the fuel rod outer diameter is increased causes the gap between the fuel rod and the grid to be significantly narrower than before. For example, as shown in FIG. 7, when the fuel assembly is constructed according to the 12 × 12 dual-cooled fuel design, the gap between the fuel rod and the unit grid is reduced to about 0.39 mm from the existing 1.45 mm.

Therefore, due to the narrow gap between the fuel rod and the unit lattice, there is a problem that the conventional method of forming and contacting the fuel rod supports at the portion orthogonal to the fuel rod so as to support the nuclear fuel rod cannot be used.

The present invention is to solve the above problems, to support the cooling system to form a spring and dimple with plastic deformation on the existing grating so that the dual-cooled fuel rods to improve the cooling performance and to obtain a high combustion and high output is soundly supported for the whole life Instead, by inserting a separate support to support the dual-cooled fuel rods near the intersection of the grids of the support grid itself, it is to ensure that the dual-cooled fuel rods can be stably supported despite the narrow gap. .

In order to achieve the above object, the support grid of the dual-cooled nuclear fuel rod according to the present invention is a plate-like first grid plate and the second grid plate and arranged in a horizontal and vertical direction at regular intervals and the first grid plate and the first Inserted near the intersection of the two grid plate is characterized in that consisting of a support provided to support the dual-cooled nuclear fuel rods.

In particular, the first grid plate is provided with a first grid slit spaced at the same interval on either side of the upper or lower, the first fastening slit is provided on both sides around the first grid slit, the second grid plate A second grid slit spaced at equal intervals is provided on either one of the upper and lower sides, and a second fastening slit is provided on both sides of the second grid slit on the other side.

In addition, the support is square As a plate having a cross-section, each edge is provided with a slit portion coupled to the first fastening slit and the second fastening slit, characterized in that each side is provided with a support for supporting the double-cooled fuel rods.

Alternatively, the support is a plate having a rectangular cross section, each corner is provided with a slit portion coupled to the first fastening slit and the second fastening slit, the concave to contact the outer diameter of the dual-cooled fuel rods on each side ( A concave, a convex or a plate-shaped support is characterized in that it is formed in the longitudinal direction.

At this time, the support is to be formed by bending the rectangular plate material at a right angle.

On the other hand, the support is a plate having a circular cross section, and arranged in four circumferential intervals at 90 degree intervals, the slits being coupled to the first fastening slit and the second fastening slit, the slits being provided between the slits. Characterized in that the support portion for supporting the dual-cooled nuclear fuel rods are formed.

At this time, the support is formed by rolling a rectangular plate in a circular shape.

On the other hand, the support is made of a cylindrical tube, arranged in four circumferential intervals at 90 degree intervals provided with a slit portion coupled to the first fastening slit and the second fastening slit, the double-cooled nuclear fuel The rod is characterized in that it is supported in contact with the outer peripheral surface of the support.

The support part may include a contact part contacting the outer diameter part of the dual cool fuel rod and a connection part bent and extended from upper and lower ends of the contact part after charging the dual cool fuel rod.

The contact portion is provided in a concave shape to have the same curvature as the curvature of the outer diameter of the dual-cooled fuel rod to make a surface contact with the dual-cooled fuel rod after charging the dual-cooled fuel rod, alternatively considering the rigidity of the support The contact portion may be provided in a convex shape or a simple planar shape protruding in the dual-cooled fuel rod direction.

In addition, the upper and lower portions of the support is characterized in that the dimple is further provided.

In addition, the first grid plate, the second grid plate and the support are welded to each other to be coupled.

Due to the above configuration, the present invention, despite the narrow gap between the fuel rod and the lattice plate so that the ultra-high-combustion dual-cooled fuel rods with an increased outer diameter of the dual-cooled fuel rods can be soundly supported for the whole life, the first grid and the second grid plate By inserting the support at the intersection of the grid plate, there is an effect that can stably support the dual-cooled fuel rods.

Moreover, there is no need to change the position of the guide tube within the fuel assembly, and the upper and lower fixtures can be used as they are so that compatibility with the components of the conventional fuel assembly can be maintained without modification or modification of the existing core structure. do.

In addition, it is possible to obtain a side effect of improving impact strength against side loads by inserting a support at an intersection without plasticizing a spring or dimple on each grating.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

8 is a perspective view showing an example of the first lattice plate according to the present invention, Figure 9 is a perspective view showing an example of the second lattice plate according to the present invention, Figure 10 shows a support applied to the first embodiment of the present invention 11 is an assembled view showing a sequence of coupling the first grid plate, the second grid plate and the support of the present invention, FIG. 12 is a plan view of the support according to the first embodiment of the present invention, and FIG. 14 is a perspective view of a support grid according to a first embodiment of the present invention, and FIG. 14 is a perspective view illustrating that a dimple is additionally provided in a support applied to the first embodiment of the present invention.

The support grid 1 according to the present invention is a plate-shaped first lattice plate 20 and the second lattice plate 30 and the first lattice plate and the first lattice plate 20 and the cross-section arranged in a horizontal and vertical direction at regular intervals The support 40 is inserted near the intersection of the two grid plates 30 and is provided to support the dual-cooled nuclear fuel rod 10.

That is, the dual cooling nuclear fuel rods in a space formed by crossing the first grid plate 20 and the second grid plate 30 in a horizontal and vertical direction surrounded by each of the first grid plate 20 and the second grid plate 30 10 is accommodated, and in order to stably support the dual-cooled nuclear fuel rod 10, the support 40 is configured to be inserted near the intersection of the first grid plate 20 and the second grid plate 30.

The first grid plate 20 of the present invention according to Figure 8 is in the shape of a plate, the first grid slit 21 and the first fastening slit 22, which is two types of slit either one of the upper or lower is provided have.

First, the first lattice slit 21 is provided spaced at regular intervals on the upper portion of the first lattice plate 20 to be coupled to the second lattice plate 30 to be described later, the first lattice slit 21 The first fastening slit 22 is provided at both left and right sides of the center so that the support body 40 for supporting the dual-cooled nuclear fuel rod 10 can be inserted.

That is, a plurality of first lattice slits 21 and first fastening slits 22 formed on the first lattice plate 20 are formed on the first lattice plate 20 while maintaining a predetermined gap therebetween. The first lattice slit 21 is coupled to the second lattice slit 31 of the second lattice plate 30 to be described later, and the first fastening slit 22 and the slit part 41 formed on the support 40 to be described later. To be combined.

Here, the first grid slit 21 and the first fastening slit 22 are provided on the upper portion of the first grid plate 20, but the position thereof may be changed to the lower side.

The second grid plate 30 of the present invention according to FIG. 9 has a plate shape, and the second grid slit 31 and the second grid slit, which are two types of slits, are formed on either one of the upper and lower portions, similar to the first grid plate 20. Two fastening slits 32 are provided.

The second grid slit 31 is spaced apart from the bottom of the second grid plate 30 at regular intervals so as to be coupled to the first grid slit 21 provided in the first grid plate 20, the second fastening The slit 32 has the same spacing as that of the first fastening slit 22 on the second grid plate 30 and is provided on both left and right sides with respect to the second grid slit 31.

If the first lattice slit 21 and the first fastening slit 22 are provided under the first lattice plate 20, the second lattice slit 31 of the second lattice plate 30 may be formed of the first lattice slit 31. It is provided at the top of the two grid plate 30 and the second fastening slit 32 should be provided at the bottom.

In this case, the support 40 for supporting the dual-cooled nuclear fuel rod 10 to be described later is coupled upward from the first grid plate 20 and the second grid plate 30.

10 shows a support 40 according to the first embodiment of the present invention, wherein the slit portion is coupled to the first fastening slit 22 and the second fastening slit 32 at each corner of the plate having a rectangular cross section. 41 is provided.

At this time, the diagonal length of the support 40 should be equal to the distance between the first fastening slit 22 and the second fastening slit 32 provided in the first grid plate 20 and the second grid plate 30, respectively. do.

That is, the support 40 is attached to the first fastening slit 22 and the second fastening slit 32 provided in each lattice board after the first lattice plate 20 and the second lattice plate 30 are joined to each other. Diagonal length of the slit portion 41 provided at each corner of the support 40 to be inserted should be equal to the horizontal or vertical spacing of the first fastening slit 22 and the second fastening slit 32. do.

In the present embodiment, the slit part 41 is provided below each corner of the support body 40 to assemble the support body 40 from above the first grid plate 20 and the second grid plate 30. However, the slits 41 may be provided on the upper corners of the support 40 to be assembled upward from the first grid plate 20 and the second grid plate 30.

For this purpose, the first fastening slit 22 and the second fastening slit 32 provided in the first grid plate 20 and the second grid plate 30 should be provided at the bottom of each grating plate.

Each side of the support 40 having the rectangular cross-section is provided with a support portion 42 for supporting the dual-cooled nuclear fuel rod 10, the support portion 42 is inserted into the dual-cooled nuclear fuel rod 10 after the double It consists of a contact portion 43 in contact with the outer diameter portion of the cooling nuclear fuel rod 10 and the connecting portion 44 extending from the upper and lower ends of the contact portion 43, respectively.

That is, the support 42 provided on each side of the support 40 protrudes toward the dual cooling nuclear fuel rod 10 at the intersection of the first lattice 20 and the second lattice 30 and the dual cooled nuclear fuel. The contact part 43 is provided so that the outer diameter part of the rod 10 may be contacted.

In addition, in order to provide a constant elastic force to the contact portion 43, the connecting portion 44 is formed by extending from the upper and lower ends of the contact portion 43, respectively.

That is, the connecting portion 44 elastically supports the contact portions 43 protruding from each side of the support 40, which in turn causes the dual cooling nuclear fuel rod 10 to be elastically supported through the contact portions 43. .

In FIG. 10, the contact portion 43 is recessed to have the same curvature as the curvature of the outer diameter of the dual-cooled fuel rod 10 so as to be in surface contact with the dual-cooled fuel rod 10 after charging the dual-cooled nuclear fuel rod 10. Although provided in a shape, in consideration of the rigidity of the support 42, the contact portion 43 may be provided in a convex shape or a simple planar shape protruding toward the dual-cooled nuclear fuel rod (10).

The support 40 is a rectangular plate material using a press device or the like to plasticize the support portion 42 consisting of the slit portion 41, the contact portion 43 and the connecting portion 44 and then bent at a right angle to the square Have a shape.

FIG. 11 shows an example of forming the support grid 1 according to the present invention by combining the first grid plate 20, the second grid plate 30, and the support 40 of the present invention.

As shown in FIG. 11, the second grid plate 30 is connected to the first grid slit 21 of the first grid plate 20 so that the second grid slit 31 of the second grid plate 30 is coupled to each other. 1 Assemble downward from above the grid plate 20. Thereafter, the intersections of the first grid plate 20 and the second grid plate 30 are fixed to each other by welding or the like.

Next, the support body 40 is coupled to the first fastening slit 22 and the second fastening slit 32 provided at each corner of the support body 40 so as to engage with the first fastening slit 22 and the second fastening slit 32. Insert from top to bottom. After that, the portions where the support body 40 and the grids intersect are fixed to each other by welding or the like.

As shown in FIGS. 12 and 13, the support 40 is inserted near the intersection of the first grid plate 20 and the second grid plate 30, and then joined by welding or the like, thereby forming a double space in a square space surrounded by the grid plates. The refrigerated nuclear fuel rods 10 are accommodated, and the dual-cooled nuclear fuel rods 10 can be stably supported by the support 42 provided in the support 40 inserted at each intersection.

FIG. 14 shows that dimples 46 are additionally provided on the upper and lower portions of each of the supports 40 of FIG. 10 to maintain the supporting integrity of the dual-cooled nuclear fuel rod 10.

The dimple 46 protrudes in the direction of the dual-cooled nuclear fuel rod 10 on each side of the support to make a surface contact with the outer diameter portion of the dual-cooled nuclear fuel rod 10, the dual-cooled nuclear fuel rod 10 After the charge of the outer diameter of the dual-cooled nuclear fuel rod (10) A concave contact surface having a curvature equal to the curvature is provided.

In FIG. 14, the dimple 46 has a concave contact surface having the same curvature as the curvature of the outer diameter of the dual-cooled nuclear fuel rod 10 so as to be in surface contact with the outer diameter of the dual-cooled nuclear fuel rod 10. In order to support the stability of the dual-cooled nuclear fuel rod 10, it may be provided with a contact surface of a convex form or a simple planar shape protruding toward the dual-cooled nuclear fuel rod 10.

FIG. 15 shows a support 40 according to a second embodiment of the present invention, wherein the slits are combined with the first fastening slit 22 and the second fastening slit 32 at each corner of a plate having a rectangular cross section. The part 41 is provided, and the support part 42 of the shape concave so that surface contact with the outer diameter part of the said dual-cooled nuclear fuel rod 10 is formed in each side in the longitudinal direction.

In addition, the support 42 has a portion of the upper and lower portions of each surface in the longitudinal direction in consideration of the rigidity of the support 40 or the fretting characteristics of the dual-cooled nuclear fuel rod 10 by the support 40. It may be formed after the incision.

When the support 42 is provided in a concave shape, the support 42 has the same curvature as the curvature of the outer diameter of the double-cooled fuel rod 10 after charging the double-cooled nuclear fuel rod 10. It is preferable to make a surface contact with the dual-cooled nuclear fuel rods (10).

In addition, the diagonal length of the support 40 should be equal to the distance between the first fastening slit 22 and the second fastening slit 32 provided in the first grid plate 20 and the second grid plate 30, respectively. do.

That is, the support 40 is attached to the first fastening slit 22 and the second fastening slit 32 provided in each lattice board after the first lattice plate 20 and the second lattice plate 30 are joined to each other. Diagonal length of the slit portion 41 provided at each corner of the support 40 to be inserted should be equal to the horizontal or vertical spacing of the first fastening slit 22 and the second fastening slit 32. .

The support 40 forms a rectangular plate by using a press device or the like to plasticize the slit part 41, the contact part and the support part 42, and then bends it at right angles to have a rectangular shape.

Since the method for manufacturing the support grid 1 according to the second embodiment of the present invention is made in the same manner as the first embodiment, it will be omitted below.

Therefore, as shown in FIGS. 16 and 17, the support body 40 is inserted near the intersection of the first lattice plate 20 and the second lattice plate 30, and then joined by welding or the like, thereby forming a square space surrounded by each lattice plate. The dual-cooled nuclear fuel rods 10 are accommodated therein, and the dual-cooled nuclear fuel rods 10 can be stably supported by the support 42 provided in the support body 40 inserted at each intersection.

FIG. 18 is a perspective view illustrating a support 40 having a convex support 42 applied to a second embodiment of the present invention, wherein the support 42 is formed in a convex form to provide the double-cooled nuclear fuel rod ( By protruding in the 10) direction, the dual cooled nuclear fuel rod 10 may be in contact with the outer diameter portion of the dual cooled nuclear fuel rod 10 to support the dual cooled nuclear fuel rod 10.

Although not shown in FIGS. 17 and 18, the support 42 may also have the form of a flat plate.

In addition, the support 42 has a portion of the upper and lower portions of each surface in the longitudinal direction in consideration of the rigidity of the support 40 or the fretting characteristics of the dual-cooled nuclear fuel rod 10 by the support 40. It may be formed after the incision.

19 shows a support 40 according to the third embodiment of the present invention, wherein the first fastening slit 22 and the second are arranged at four circumferential positions of a plate having a circular cross section at 90 degree intervals. A slit part 41 is provided to be coupled to the fastening slit 32, and a support part 42 supporting the dual cooling nuclear fuel rod 10 is provided between the four slit parts 41.

At this time, the interval between the slit portion 41 facing each of the slit portion 41 provided on the circumference of the support 40 is the first fastening slit 22 and the second fastening slit ( It should be equal to the interval in 32).

Four circumferential portions of the support 40 having the circular cross-section are provided at the same interval to support the support 42 for the dual-cooled nuclear fuel rod 10, the support 42 is the dual-cooled nuclear fuel rods (10) After the charging is composed of a contact portion 43 is in contact with the outer diameter portion of the dual-cooled nuclear fuel rod 10 and the connecting portion 44 extending from the upper and lower ends of the contact portion 43, respectively.

That is, the support part 42 provided on the support 40 protrudes toward the dual cooling nuclear fuel rod 10 at the intersection of the first lattice plate 20 and the second lattice plate 30 and the dual cooling nuclear fuel rod ( The contact part 43 is provided so that the outer diameter part of 10 may be contacted.

In addition, in order to provide a constant elastic force to the contact portion 43, the connecting portion 44 is formed by extending from the upper and lower ends of the contact portion 43, respectively.

That is, the connecting portion 44 elastically supports the contact portions 43 protruding from each side of the support 40, which in turn makes the dual cooling fuel rod 10 elastically support through the contact portions 43.

In FIG. 19, the contact portion 43 has the same curvature as the curvature of the outer diameter of the dual-cooled nuclear fuel rod 10 to be in surface contact with the dual-cooled nuclear fuel rod 10 after charging the dual-cooled nuclear fuel rod 10. Although provided in a concave shape, in consideration of the rigidity of the support portion 42, the contact portion 43 may be provided in a convex shape or a simple planar shape protruding toward the dual-cooled nuclear fuel rod (10) direction.

The support 40 is formed of a rectangular plate by using a press device or the like, after plasticizing the support part 42 formed of the slit part 41, the contact part 43, and the connecting part 44, and rolling it in a circular shape. .

Therefore, as shown in FIGS. 20 and 21, the support body 40 is inserted near the intersection of the first grid plate 20 and the second grid plate 30, and then joined by welding or the like, thereby forming a square space surrounded by the grid plates. The dual-cooled nuclear fuel rods 10 are accommodated therein, and the dual-cooled nuclear fuel rods 10 can be stably supported by the support 42 provided in the support body 40 inserted at each intersection.

FIG. 22 illustrates that dimples 46 are additionally provided on the upper and lower portions of each of the supports 40 of FIG. 19 to maintain the supporting integrity of the dual-cooled nuclear fuel rod 10.

The dimple 46 protrudes in the direction of the dual-cooled nuclear fuel rod 10 on each side of the support to make a surface contact with the outer diameter portion of the dual-cooled nuclear fuel rod 10, the dual-cooled nuclear fuel rod 10 After the charge of the outer diameter of the dual-cooled nuclear fuel rod (10) A concave contact surface having a curvature equal to the curvature is provided.

In FIG. 22, the dimple 46 has a concave contact surface having the same curvature as the curvature of the outer diameter of the dual-cooled nuclear fuel rod 10 so as to be in surface contact with the outer diameter of the dual-cooled nuclear fuel rod 10. In order to support the stability of the dual-cooled nuclear fuel rod 10, it may be provided with a contact surface of a convex form or a simple planar shape protruding toward the dual-cooled nuclear fuel rod 10.

FIG. 23 shows a support 40 according to a fourth embodiment of the present invention, wherein the support 40 is formed of a cylindrical tube. The slit portion 41 is arranged in four circumferential positions at 90 degree intervals so as to be coupled to the first fastening slit 22 and the second fastening slit 32, and the double cooling nuclear fuel rod 10 is provided. It is supported by being in direct contact with the outer circumferential surface of the support 40.

At this time, the interval between the slit portions 41 facing each other on the circumference of the support 40 is the same as the interval between the first fastening slit 22 and the second fastening slit 32 provided in each of the gratings. It should be done.

In the first to third embodiments, the support 40 is formed by bending a rectangular plate at right angles or by rolling it in a circular shape. However, in the present embodiment, the support 40 is formed by using a cylindrical tube itself having a circular cross section. To provide a plastic working process, the slits 41 arranged at intervals of 90 degrees by a press device or the like.

Therefore, as shown in FIGS. 24 and 25, the support body 40 is inserted near the intersection of the first grid plate 20 and the second grid plate 30, and then joined by welding or the like, thereby forming a square space surrounded by each grid plate. The dual-cooled nuclear fuel rods 10 are accommodated therein, and the outer diameter portion of the dual-cooled nuclear fuel rods 10 is directly contacted with the outer circumferential surface of the support 40 having a circular cross section inserted into each intersection to take advantage of the rigidity of the support 40 itself. By doing so, it is possible to stably support the dual cooling nuclear fuel rod (10).

While the invention has been shown and described with respect to particular embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention as indicated by the appended claims. Anyone can grow up easily.

1 is a front view schematically showing a nuclear fuel assembly according to the prior art,

Figure 2 is a plan sectional view schematically showing a cross section of the fuel assembly according to the prior art,

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

Figure 4 is a perspective view schematically showing a support grid applied to the nuclear fuel assembly according to the prior art,

Figure 5 is a perspective view schematically showing a unit grid of the support grid for supporting the nuclear fuel rods according to the prior art,

6 is a plan sectional view schematically showing a cross section of a dual-cooled nuclear fuel rod,

7 is a plan sectional view schematically showing a cross section of a dual-cooled fuel assembly;

8 is a perspective view showing an example of a first lattice plate according to the present invention;

9 is a perspective view showing an example of a second lattice plate according to the present invention;

10 is a perspective view showing a support applied to the first embodiment of the present invention;

11 is an assembly view showing a procedure of combining the first grid plate, the second grid plate and the support of the present invention,

12 is a plan view of a support grid according to a first embodiment of the present invention;

13 is a perspective view of a support grid according to a first embodiment of the present invention;

14 is a perspective view showing that the dimple is additionally provided in the support applied to the first embodiment of the present invention;

15 is a perspective view showing a support applied to a second embodiment of the present invention;

16 is a plan view of a support grid according to a second embodiment of the present invention;

17 is a perspective view of a support grid according to a second embodiment of the present invention;

18 is a perspective view showing a support having a convex support applied to a second embodiment of the present invention;

19 is a perspective view showing a support applied to the third embodiment of the present invention;

20 is a plan view of a support grid according to a third embodiment of the present invention;

21 is a perspective view of a support grid according to a third embodiment of the present invention;

FIG. 22 is a perspective view illustrating that dimples are additionally provided on a support applied to a third embodiment of the present invention; FIG.

23 is a perspective view showing a support applied to the fourth embodiment of the present invention;

24 is a plan view of a support grid according to a fourth embodiment of the present invention;

25 is a perspective view of a support grid according to a fourth embodiment of the present invention.

** Explanation of symbols for main parts of the drawing **

1: support grid 10: dual cooling nuclear fuel rod

11: sintered compact 12: inner side cover tube

13: outer cladding tube 20: first lattice plate

21: first lattice slit 22: first fastening slit

30: second lattice plate 31: second lattice slit

32: second fastening slit 40: support

41: slit part 42: support part

43: contact 44: connection

46: dimple 100: nuclear fuel assembly

110: nuclear fuel rod 115: subwaterway

118: spring 119: dimple

120: upper fixture 130: lower fixture

140: guide 150: support grid itself

Claims (18)

A plate-shaped first lattice plate 20 arranged to intersect in a horizontal and vertical direction at a predetermined interval; and a second lattice plate 30; And a support 40 inserted near the intersection point of the first grid plate 20 and the second grid plate 30 to support the dual-cooled nuclear fuel rod 10. Double cooling using a cross-point support The support grid of the nuclear fuel rods (10). The method of claim 1, The first grid plate 20 is provided with a first grid slit 21 spaced at the same interval on either side of the upper or lower, the first fastening slit 22 on both sides of the first grid slit 21 ), The second grid plate 30 is provided with a second grid slit 31 spaced at the same interval on either side of the upper or lower, the second fastening slit on both sides around the second grid slit 31 on the other side A support grid of a dual-cooled nuclear fuel rod (10) using an intersection support, characterized in that the (32) is provided. The method of claim 2, The support body 40 is a plate having a rectangular cross section, and a slit portion 41 coupled to the first fastening slit 22 and the second fastening slit 32 is provided at each corner, and the double cooling is provided at each side. Support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that the support 42 for supporting the nuclear fuel rod (10) is provided. The method of claim 3, wherein The support part 42 is connected to the contact portion 43 and the upper and lower ends of the contact portion 43 formed in contact with the outer diameter portion of the dual-cooled fuel rod 10 after the charge of the dual-cooled nuclear fuel rod 10 is bent ( 44. The support grid of the dual-cooled nuclear fuel rod (10) using the cross-point support, characterized in that consisting of. The method of claim 4, wherein The support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that the dimple (46) is further provided on the upper and lower portions of the support (42). The method of claim 2, The support 40 is a plate having a rectangular cross section, and a slit portion 41 coupled to the first fastening slit 22 and the second fastening slit 32 is provided at each corner, and the double surface is provided on each side. A double-cooled fuel rod using a cross-point support, characterized in that the support 42 in the form of a concave, convex or plate is formed in the longitudinal direction so as to contact the outer diameter of the cooling fuel rod 10. (10) support grid itself. The method of claim 6, The concave support 42 has a dual-cooled nuclear fuel rod 10 using a cross-point support, characterized in that it has the same curvature of the outer diameter of the dual-cooled nuclear fuel rod 10 after loading the dual-cooled nuclear fuel rod 10. Support grid. The method according to any one of claims 3 to 7, The support 40 is a support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that formed by bending a rectangular plate at a right angle. The method of claim 2, The support body 40 is a plate having a circular cross section and is arranged at four circumferential intervals at 90 degree intervals so that the slit part 41 is coupled to the first fastening slit 22 and the second fastening slit 32. The support grid of the dual-cooled fuel rod (10) using the cross-point support, characterized in that the support portion 42 is provided between the slit portion (41) for supporting the dual-cooled nuclear fuel rod (10). The method of claim 9, The support part 42 is connected to the bent portion extending from the upper and lower ends of the contact portion 43 and the contact portion 43 in contact with the outer diameter portion of the dual-cooled nuclear fuel rod 10 after charging the dual-cooled nuclear fuel rod 10 ( 44. The support grid of the dual-cooled nuclear fuel rod (10) using the cross-point support, characterized in that consisting of. The method of claim 10, The support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that the dimple (46) is further provided on the upper and lower portions of the support (42). The method according to claim 5 or 11, wherein The dimple 46 is a double cooling using a cross point support, characterized in that the contact surface of the concave (concave), convex (convex) or plate (plate) shape is provided to contact the outer diameter of the dual-cooled nuclear fuel rod (10). Support grid of the nuclear fuel rod (10). The method according to claim 4 or 10, The contact portion 43 is a double-cooled fuel rod using a cross-point support characterized in that it is provided with a concave shape to have the same curvature as the curvature of the outer diameter of the double-cooled nuclear fuel rod 10 after charging the dual-cooled nuclear fuel rod (10). (10) support grid itself. The method according to claim 4 or 10, The contact portion 43 is a support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that provided in the convex shape protruding in the direction of the dual-cooled nuclear fuel rods (10). The method according to claim 4 or 10, The contact portion 43 is a support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that provided in a planar shape. The method of claim 9, The support 40 is formed by rolling a rectangular plate in a circular shape A support grid of a dual cooled nuclear fuel rod (10) using an intersection support. The method of claim 2, The support body 40 is formed of a cylindrical tube, and is arranged at four intervals at 90 degree intervals, and the slit part 41 coupled to the first fastening slit 22 and the second fastening slit 32. Is provided, the dual-cooled fuel rod (10) support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that the support is supported in contact with the outer peripheral surface of the support (40). The method of claim 1, The first lattice plate (20), the second lattice plate (30) and the support (40) is a support grid of the dual-cooled nuclear fuel rods (10) using the cross-point support, characterized in that welded to each other.

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