KR20080019876A - Upper and lower end plug of an annular nuclear fuel rod - Google Patents

Abstract

Upper and lower end plugs of an annular nuclear fuel rod are provided to prevent a foreign material from being inserted at the time of the inflow of cooling water by using a foreign material filtering device in an internal water path of the lower end plug. Upper and lower end plugs(10,30) are provided on upper and lower ends of an annular nuclear fuel rod(1). The upper end plug includes an inside bonding surface(13a) and an outside bonding surface(13b). The inside bonding surface is formed in the inside of an upper binding piece(13) so that an upper surface of an inside tube(7) is bonded by center alignment. The outside bonding surface is formed outside the upper binding piece so that an upper surface of an outside tube(8) is bonded by the central alignment. The lower end plug includes an inside bonding surface(33a) and an outside bonding surface(33b). The inside bonding surface of the lower end plug is formed inside a lower binding piece(33) so that a lower surface of the inside tube is bonded by the center alignment. The outside bonding surface of the lower end plug is formed outside the lower binding piece so that a lower surface of the outside tube is bonded by the center alignment.

Description

Upper and lower end plug of an annular nuclear fuel rod

1 is a front sectional view schematically showing a cylindrical nuclear fuel rod according to the prior art,

Figure 2 is a plan cross-sectional view schematically showing an annular fuel rod in the prior art,

Figure 3 is a perspective view schematically showing the upper and lower end caps of the annular fuel rod according to the present invention installed on the annular fuel rod,

4 is a cross-sectional view schematically showing the upper and lower end caps of the annular fuel rod according to the present invention installed on the annular fuel rod;

5 is a plan view schematically showing a foreign matter filtering device applied to the lower end stopper of the upper and lower end stoppers of the annular fuel rod according to the present invention;

6 is a plan view schematically showing another embodiment of a foreign matter filtering device applied to the lower end stopper of the upper and lower end stoppers of the annular nuclear fuel rod according to the present invention;

7 is a cross-sectional view schematically showing a state in which a handling groove for coupling a nuclear fuel rod handling tool is formed on the inner and outer edges of the upper and lower end caps of the annular fuel rod according to the present invention;

8 is a perspective view schematically showing an annular fuel rod to which another embodiment of the upper and lower end plugs of the annular fuel rod according to the present invention is applied;

9 is a cross-sectional view schematically showing the upper and lower end caps of the annular fuel rod according to the present embodiment installed on the annular fuel rod;

10 is a cross-sectional view schematically showing a state in which a handling groove for coupling a nuclear fuel rod handling tool is formed on the inner and outer edges of the upper and lower end caps of the annular fuel rod according to the present embodiment;

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

1: annular nuclear fuel rod, 3: sintered body,

5: inner channel, 7: inner tube,

8: outer tube, 10: upper end cap,

11: main outlet of the inner channel, 13: upper coupling piece,

13a: inner joining surface, 13b: outer joining surface,

15a: upper outer coupling groove, 15b: upper inner coupling groove,

30: lower end cap, 31: main entrance of the inner channel,

33: lower coupling piece, 33a: inner joining surface,

33b: outer joining surface, 35a: lower outer joining groove,

35b: lower inner coupling groove, 37: mounting groove,

50: foreign material filtering device, 51: foreign material filtering pin.

The present invention relates to an annular fuel rod, and more particularly, to form a coupling piece protruding from the lower surface and the upper surface of the upper and lower end caps coupled to the inner tube and the outer tube of the annular fuel rod, and in each coupling piece, Laser welding of the outer tube from the outside or electric resistance welding makes it easy to manufacture the annular fuel rod, and it is possible to improve the sealing efficiency of the welded part as well as to clean the welded part. In addition to preventing the inflow of extraneous foreign matter when the inlet of the coolant, it relates to the upper and lower end caps of the annular nuclear fuel rods easy to install and manufacture by installing the foreign matter filtration device in a circular groove or a spiral groove.

Currently, nuclear fuel rods of cylindrical shape are used in commercial nuclear power plants. Here, as shown in FIG. 1, the cylindrical nuclear fuel rod 100 is composed of a zirconium alloy cladding tube 101 and a sintered body 103, and a gap is formed between the cladding tube 101 and the sintered body 103. do.

In this case, after filling hundreds of sintered bodies having a cylindrical shape in one covering tube and pressing the sintered bodies with a spring provided separately, both ends of the covering tube are sealed.

In general, the diameter of the sintered body is about 9mm, the length is about 10mm, the diameter of the nuclear fuel rod is about 10mm, the length of the nuclear fuel rod is about 4m, of which about 3.6m is charged with the sintered body, the rest is a spring.

Here, the sintered body applied to the nuclear fuel rod is usually a ceramic material containing fissile materials such as uranium and plutonium, and is produced by a method of compression molding the powder and then sintering at high temperature.

During the combustion of the fuel rods in the reactor, heat from the sintered body is transferred to the cooling water through the cladding through the gap. At this time, the coolant flows to the outside of the nuclear fuel rod while joining the cladding tube.

Conventional cylindrical fuel rods having such a configuration are limited in performance in terms of temperature and heat flux. That is, since the thermal conductivity of the sintered body is low, the heat produced by nuclear fission cannot be quickly transferred to the cooling water, and thus the sintered body has a much higher temperature than the cooling water.

Here, the temperature of the cooling water is in the range of 320 ℃ ~ 340 ℃, the temperature of the sintered body is the highest in the center, the surface is the lowest, the core temperature of the sintered body in the normally burning nuclear fuel rod is in the range of 1000 ℃ to 1500 ℃.

At this time, since the temperature of the sintered body is in a high state, all reactions depending on the temperature are accelerated, thereby degrading the performance of the material. In particular, the higher the combustion degree, the worse the performance deterioration, there was a problem that can result in the margin of safety (Margin) in a number of virtual reactor accidents when the sintered body is in a high temperature state.

In addition, when the heat flux of the nuclear fuel rod is increased, the departure of nucleate boiling may occur. Here, when the nuclear boiling departure occurs, since a bubble film is formed on the surface of the cladding tube, the heat transfer is severely lowered, and the nuclear fuel rod may be damaged.

In order to solve the problems as described above, a nuclear fuel rod having an annular type structure and cooling water flowing simultaneously into and out of the fuel rod has been proposed.

As shown in FIG. 2, the inner and outer tubes 201 and 203 respectively provided on the inner side and the outer side, and the annular sintered body 205 inserted in the space between the inner tube 201 and the outer tube 203, respectively. It is composed. That is, the nuclear fuel rod 200 is a structure in which the inner tube 201 is provided on the inner circumference of the sintered body 205 formed in an annular shape, and the outer tube 203 is surrounded on the outer circumference thereof. After installing the end caps on both ends of the nuclear fuel rods 200 in a pressurized state by the spring made of a structure for sealing by welding.

Here, the coolant flows through the inner channel 207 and the outer space of the outer tube 203 which are vertically penetrated inside the inner tube 201 of the annular fuel rod 200.

As described above, since the coolant is additionally flowed along the hottest center of the nuclear fuel rod, the temperature of the nuclear fuel rod is greatly reduced, and the thermal shear area of the nuclear fuel rod is increased to reduce the heat flux and thus the thermal margin. Could expect an improvement.

Here, the upper and lower end caps respectively installed at both ends of the annular fuel rod are joined to both ends of the inner tube and the outer tube by welding, but the upper and lower ends of the inner and outer tubes and the upper and lower end caps In the welding operation of the welding position is not easy, there is a problem that the space between the inner tube and the outer tube is not uniform, and the welded portion is broken.

On the other hand, in order to reduce the temperature of the nuclear fuel rods, there was a problem that the temperature of the nuclear fuel rods is increased by blocking foreign substances into the inner fuel rods when foreign matter flows into the inner channel of the annular fuel rods. That is, when foreign matter suspended along the coolant is caught in the inner channel of the nuclear fuel rods to block the flow path, the foreign matter blocks the flow of the cooling water and the flow rate of the inner channel decreases, so that the heat generated from the inner channel wall of the nuclear fuel rod cannot be cooled. As the temperature of the wall is increased or the temperature continues to rise, the wall of the internal waterway can be damaged, which can cause a safety accident such as a nuclear reactor accident. .

In order to solve the problem as described above, the Republic of Korea Patent Registration No. 10-0074788 (1994), 10-0077453 (1994), 10- for the annular nuclear fuel rod to which the foreign matter filtering device for removing the foreign matter suspended in the inner channel 0010878 (1999), 10-0453268 (2004), etc. proposed in the Republic of Korea Patent No. 66615 (2006), but most of the existing foreign matter filtration device is a patent applied to the aggregate of the existing cylinder form consisting of a structure formed integrally with the lower fixture. As a result, foreign matter can escape through the gap between the bottom fixture and the neighboring bottom fixture and between the bottom fixture and the wall of the core.

In addition, the foreign matter filtering device of the lower end of the bundle of the nuclear fuel rod assembly is not able to completely filter the foreign matters, foreign matters coming out of the lower stationary body into the internal channel, as well as complicated structure, difficult installation There was a problem.

The present invention has been made in order to solve the above problems, the upper and lower end caps coupled to the inner tube and the outer tube of the annular fuel rod protruding to form a coupling piece on the upper surface, and in each coupling piece, Laser welding of the outer tube from the outside or electric resistance welding makes it easy to manufacture the annular fuel rod, and it is possible to improve the sealing efficiency of the welded part as well as to clean the welded part. It is an object of the present invention to provide an upper and lower end cap of an annular nuclear fuel rod that is easy to install and manufacture by installing a foreign matter filtration device in a circular groove or a spiral groove, as well as preventing separate foreign matter from entering the cooling water.

In order to achieve the above object, the present invention, the sintered body is formed in an annular shape, and the inner and outer tubes are respectively provided on the inner and outer periphery of the sintered body and the upper and lower ends of the inner and outer tubes, respectively, An annular nuclear fuel rod comprising an upper and lower end cap through which an inner channel main outlet and an inner channel main inlet are formed at a center thereof, wherein an upper coupling piece protrudes in a circumferential direction at a center of a lower side of the inner channel main outlet. And an inner joining surface formed inside the upper joining piece so that the upper surface of the inner tube is centered and joined, and an outer joining surface formed outside the upper joining piece so that the upper surface of the outer tube is centered and joined. Upper end closure; And an inner joining surface formed inside the lower joining piece so that the lower joining piece is protruded in the circumferential direction at the center of the upper surface of the inner channel main inlet, and the lower surface of the inner tube is aligned in the center and the lower joining piece; A lower end cap having an outer joining surface formed on an outer side of the lower joining piece so that the surfaces are aligned in a center; Characterized in that consisting of a configuration including a.

The lower end cap further includes an installation groove formed at an inner circumference of the lower side of the inner channel main entrance, and a foreign matter filtering device coupled to the installation groove.

Here, the foreign matter filtration device is formed in an annular shape, consisting of a foreign matter filter pin that is interconnected in the cross shape in the vertical and horizontal direction at the center thereof.

Alternatively, the foreign matter filtering device is formed in an annular shape, consisting of a plurality of foreign matter filtering pins connected in a grid form vertically and horizontally to the center thereof.

In addition, the foreign material filtering device is composed of a foreign material filter pin that is interconnected in the cross shape in the vertical and horizontal direction at the center.

In addition, the foreign material filtering device is composed of a foreign material filter pin connected in a plurality of grids vertically and horizontally in the center.

At this time, the installation groove is formed in a columnar or spiral shape.

Here, an upper outer coupling groove and a lower outer coupling groove are formed on the outer circumferential edges of the upper end cap and the lower end stopper to engage the nuclear fuel rod handling tool in the circumferential direction.

On the other hand, the upper inner end and the lower end of the inner end of the upper end stopper, the inner inner coupling groove and the lower inner coupling groove for coupling the nuclear fuel rod handling tool in the circumferential direction is formed, the upper, lower inner coupling groove The upper and lower end caps are formed to be close to each inner joining surface.

Here, each end of the inner and outer circumference of the upper end cap and the lower end cap is inclined to reduce the fluid resistance of the cooling water.

Sintered body formed in an annular shape, and the inner and outer tubes and the upper and lower ends of the inner and outer tubes respectively installed on the inner and outer periphery of the sintered body, respectively, the inner channel main outlet and the inner channel main inlet In the annular nuclear fuel rods including upper and lower end caps formed therethrough, the upper coupling piece for joining the upper surface of the inner tube to the lower edge of the inner channel main outlet is formed to protrude, and the outer surface of the outer nuclear fuel rod. An upper end cap to which the inner side of the tube is joined; And a lower end cap which protrudes a lower coupling piece for joining the lower surface of the inner tube to the upper edge of the inner channel main entrance, and the lower surface of the outer tube to the edge thereof; It consists of a configuration comprising a.

The lower end cap further includes an installation groove formed at an inner circumference of the lower side of the inner channel main entrance, and a foreign matter filtering device coupled to the installation groove.

Here, the foreign matter filtration device is formed in an annular shape, consisting of a foreign matter filter pin that is interconnected in the cross shape in the vertical and horizontal direction at the center thereof.

Alternatively, the foreign matter filtering device is formed in an annular shape, consisting of a plurality of foreign matter filtering pins connected in a grid form vertically and horizontally to the center thereof.

In addition, the foreign material filtering device is composed of a foreign material filter pin that is interconnected in the cross shape in the vertical and horizontal direction at the center.

In addition, the foreign material filtering device is composed of a foreign material filter pin connected in a plurality of grids vertically and horizontally in the center.

At this time, the installation groove is formed in a columnar or spiral shape.

Here, the upper outer coupling groove and the lower outer coupling groove for the nuclear fuel rod handling tool in the circumferential direction is formed in the outer circumferential position of the upper end plug and the lower end plug.

On the other hand, the upper inner end and the lower end of the inner end of the upper end stopper, the inner inner coupling groove and the lower inner coupling groove for coupling the nuclear fuel rod handling tool in the circumferential direction is formed, the upper, lower inner coupling groove The upper and lower end caps are formed to be close to the upper and lower coupling pieces.

Here, each end of the inner and outer circumference of the upper end cap and the lower end cap is inclined to reduce the fluid resistance of the cooling water.

Hereinafter, with reference to the accompanying drawings, an embodiment according to the present invention will be described in detail.

3 is a perspective view schematically showing the upper and lower end caps of the annular fuel rod according to the present invention installed in the annular fuel rod, and FIG. 4 is the upper and lower end caps of the annular fuel rod according to the present invention installed in the annular fuel rod. Figure 5 is a cross-sectional view schematically showing a state, Figure 5 is a plan view schematically showing a foreign matter filtering device applied to the lower end stopper of the upper and lower end stopper of the annular nuclear fuel rod according to the present invention, Figure 6 is a view of the annular nuclear fuel rod 7 is a plan view schematically showing another embodiment of the foreign matter filtering device applied to the lower end stopper of the upper and lower end stoppers, and FIG. 7 is a nuclear fuel rod handling tool coupled to an inner circumference of the upper and lower end stoppers of the annular fuel rod according to the present invention. Is a cross-sectional view schematically showing a state in which a handling groove is formed.

As shown in the figure, the annular nuclear fuel rod 1 according to the present invention has a sintered body 3 formed in an annular shape having an inner channel 5 at the center thereof, and the inner and outer circumferences of the sintered body 3, respectively. Inner and outer tubes 7 and 8 to be installed are included.

Here, the upper end stopper 10 of the upper and lower end stoppers 10 and 30 of the annular nuclear fuel rod 1 has an inner channel main outlet 11 penetratingly formed at its center, and the inner channel main outlet 11 The upper coupling piece 13 protrudes in the circumferential direction at the center of the lower surface of the inner side, and the inner joining surface 13a for joining the upper surface of the inner tube 7 to the inner side of the upper joining piece 13. ) Is formed, and an outer joining surface 13b for joining the upper surface of the outer tube 8 to the outside thereof is formed.

In addition, the lower end end cap 30 of the annular fuel rod 1 has an inner channel main inlet 31 formed therethrough at a central portion thereof, and a lower portion in the circumferential direction at the center of the upper side of the inner channel main inlet 31. The engaging piece 33 is protruded, the inner joining surface 33a for joining the lower surface of the inner tube 7 inside the lower engaging piece 33 is formed, the outer tube 8 on the outside The outer joining surface 33b for joining the lower surface of the is formed.

The upper and lower end caps 10, 30 by the structure as described above is formed in the circumferential direction protruding in the center of the lower side and the upper side of the inner channel main outlet 11 and the inner channel main inlet 31, When the inner tube 7 and the outer tube 8 are coupled to the lower coupling pieces 13 and 33, center alignment between the tubes 7 and 8 is facilitated.

Here, the width of the upper and lower coupling pieces 13 and 33 protruding from the upper side and the lower side of the annular fuel rod 1, the lower end caps 10 and 30, the width of the inner tube (7) and It is made to correspond to the width of the annular sintered body 3 inserted between the outer tubes 8.

By the structure and shape as described above, the inner channel 5 and the upper end cap formed with the coolant flowing through the lower channel main inlet 31 of the lower end cap 30 inside the inner tube 7 ( 10) to prevent the rise of the temperature of the nuclear fuel rod (1) while flowing through the main outlet 11 of the domestic water.

Here, an installation groove 37 is formed in the circumferential direction at an inner circumferential edge of the lower end plug 30 of the lower end plug 30 at an inner circumferential side of the lower end plug 30, and filters foreign substances in the installation groove 37. The apparatus 50 is provided.

At this time, the foreign matter filtering device 50 is formed in an annular shape, made of a cross-shaped foreign matter filtering pin 51 of the cross shape connected to each other in the vertical and horizontal direction in the center. That is, the foreign matter filtering device 50 is formed in an annular shape having a circular cross section, and the foreign matter filtering device 51 has a structure in which two foreign matter filtering pins 51 are connected in a cross shape.

In the embodiment of the present invention, the foreign matter filtering device 50 is formed in an annular shape, but has a cross shape that is interconnected in the vertical and horizontal directions at its center, but the foreign matter filtering device 50 is formed in an annular shape. It is also possible to have a structure in which a plurality of foreign matter filter pins 51 are connected in a lattice form in the vertical and horizontal directions at the center thereof.

In addition, in one embodiment of the present invention, the foreign matter filtration device 50 is formed in an annular shape, but has a cross shape that is interconnected in the vertical and horizontal directions at its center, but the foreign matter filtration device 50 has two It is composed of only foreign matter filter pin 51, the center and the center is formed in the cross shape interconnected in the vertical and horizontal direction, or the foreign matter filtering device 50 in the vertical and horizontal direction to the center of the plurality of foreign matter filter pins (51) It is also possible to have a structure in which) is connected in a lattice form.

Here, the foreign substance filtering pin 51 constituting the foreign substance filtering device 50 is preferably formed in a circular cross section, the cross section of the foreign substance filtering pin 51 has an ellipse streamline or triangular, square, etc. It is also possible to be formed in various other shapes.

As described above, only the coolant except the foreign matter flows into the inner channel 5 of the nuclear fuel rod 1 by the foreign substance filtering device 50 installed in the inner channel main inlet 31 of the lower end cap 30. As a result, not only the inner channel 5 of the nuclear fuel rod 1 is prevented from being blocked by foreign substances, but also a smooth inflow of cooling water is possible, thereby helping to cool the nuclear fuel rod 1.

On the other hand, it is preferable to position the foreign matter filtration device 50 in the installation groove 37 of the lower end cap 30, and then fix the end of the foreign matter filtration device 50 in the installation groove 37 by a welding process.

In one embodiment of the present invention has a structure in which the foreign matter filtration device 50 is coupled to the installation groove 37 formed on the inner periphery of the lower inlet end 30 by the inner end of the lower end cap 30 and then joined by welding. However, after forming the installation groove (37) in the circumferential or helical shape at the inner periphery of the lower main end 31 of the lower end end cap 30 in the circumferential or spiral shape, the foreign matter filtration device (50) in the installation groove (37) It is also possible to have a structure for bonding.

On the other hand, the inner and outer periphery of the upper end cap 10 and the lower end cap 30 is formed to be inclined, thereby reducing the fluid resistance of the cooling water introduced to prevent the high temperature generated in the nuclear fuel rod (1) To reduce.

Here, the upper outer coupling groove 15a and the lower outer coupling groove 35a for coupling the nuclear fuel rod handling tool (not shown) in the circumferential direction to the outer circumferential position of the upper end cap 10 and the lower end cap 30. ) Is formed.

In an embodiment of the present invention, the upper and lower outer coupling grooves 15a and 35a are formed to couple and install the nuclear fuel rod handling tool in the circumferential direction at the outer peripheral positions of the upper and lower end caps 10 and 30. However, as shown in Figure 7, the upper and lower end coupling grooves (15b, 35b) for the nuclear fuel rod handling tool is coupled and installed in the inner circumferential position of the end caps (10, 30) It is also preferably formed, in this case, the upper and lower inner coupling grooves (15b, 35b) the position of the upper and lower ends of the inner tube 7, the inner side of the lower end stopper (10, 30) is joined It is preferable to be formed in proximity to the surfaces 13a and 33a.

As described above, the upper and lower inner coupling grooves 15b and 35b are formed on the inner circumference of the inner and outer peripheral surfaces 13a and 33a of the upper and lower end caps 10 and 30 so that the respective inner joints are formed. When the inner tube 7, which abuts against the surfaces 13a and 33a, is extended in the longitudinal direction, the inner joints of the upper and lower end caps 10 and 30 of the upper, lower, and abutment surfaces of the inner tube 7. The surfaces 13b and 33b are elastically deformed in predetermined portions to fix and support the inner tube 7.

That is, the upper and lower inner coupling grooves 15b and 35b are formed on the inner circumferences of the upper and lower end caps 10 and 30 so that the upper and lower surfaces of the inner and outer tubes 7 and 8 come into contact with each other. Thermal expansion or neutrons in a reactor operating environment by varying the thicknesses of the respective inner joining surfaces 13a and 33a and the outer joining surfaces 13b and 33b of the upper and lower end caps 10 and 30 to be welded or electric resistance welded. When the longitudinal growth of the inner tube 7 and the outer tube 8 is different due to the growth due to irradiation, the phenomenon of the bow of the annular fuel rod 1 can be alleviated.

In an embodiment of the present invention, the upper and lower inner coupling grooves 15b and 35b are formed on the inner circumferences of the upper and lower end caps 10 and 30, but the inner and inner tubes 7 are formed in close proximity to the inner tube 7. Each inner joining surface (13a, 33a) that the tube (7) abuts has a structure that absorbs the bending phenomenon of the nuclear fuel rod (1), but the image formed on the outer periphery of the upper, lower end caps (10, 30) And the lower outer coupling grooves 15a and 35a are formed in close proximity to each of the outer joining surfaces 13b and 33b contacting the upper and lower surfaces of the outer tube 8 to absorb even the bending phenomenon of the outer tube 8. It is also possible to consist of.

Here, as shown in FIGS. 4 and 7, the inner joining surfaces 13a and 33a and the respective outer joinings of the upper and lower engaging pieces 13 and 33 of the upper and lower end closures 10 and 30, respectively. The portions marked in bold portions on the joints of the surfaces 13b and 33b and the upper and lower surfaces of the inner and outer tubes 7 and 8 represent welded portions.

In one embodiment of the present invention, the upper and lower end caps 30 and the upper end cap 10 are sequentially coupled to the inner and outer tubes 7 and 8, and then the upper and lower ends are formed by laser welding or electric resistance welding. After attaching the stoppers 10 and 30 to the upper and lower portions of the inner tube 7 and the outer tube 8, the foreign material filtering device 50 is installed in the installation groove 37 of the lower end cap 30. Preferably, the upper and lower end caps 10 and the lower end cap 30 are sequentially coupled to the inner and outer tubes 7 and 8, and the upper and lower end caps 10 and 10 are formed by laser welding or electric resistance welding. It is also possible to install the foreign matter filtration device 50 in the installation groove 37 of the lower end cap 30 after the 30 is bonded to the upper and lower portions of the inner tube 7 and the outer tube 8.

In addition, in an embodiment of the present invention, the upper and lower end caps 10 and 30 are welded to the inner and outer tubes 7 and 8, and the foreign material is filtered through the installation grooves 37 of the lower end cap 30. Although the device 50 is configured to be welded, the foreign matter filtration device 50 is welded to the installation groove 37 of the lower end cap 30, and then the upper and outer tubes 7 and 8 are installed on the inner and outer tubes 7 and 8. It is also possible to laser weld the lower end caps 10 and 30, or to perform electrical resistance welding.

8 is a perspective view schematically showing an annular fuel rod to which the upper and lower end caps of the annular fuel rod according to the present invention is applied, and FIG. 9 is an upper and lower end cap of the annular fuel rod according to the present embodiment. 10 is a cross-sectional view schematically showing a state in which the handling grooves for coupling the nuclear fuel rod handling tool are formed on the inner circumference of the upper and lower end caps of the annular nuclear fuel rod according to the present embodiment.

As shown in the figure, in the present embodiment, the inner channel main outlet 11 is formed through the center of the upper end cap 10 of the upper and lower end caps 10 and 30 of the annular fuel rod, but the inner channel On the lower side edge of the main outlet 11, an upper engaging piece 13 for protruding to the upper surface of the inner tube 7 is formed, and on the outer side of the upper end cap 10 of the outer tube 8 The inner side is joined.

In addition, the lower end cap 30 has a water inlet canal main inlet 31 is formed in the center, the lower portion for bonding to the lower surface of the inner tube (7) to the upper edge of the inner channel main inlet 31 The engaging piece 33 is protruded, and the lower surface of the outer tube 8 is joined to the edge.

To this end, the outer diameter of the upper end cap 10 is formed smaller than the outer diameter of the lower end cap 30, it is made to have a difference as much as the width of the outer tube (8). As described above, the outer diameter of the upper end cap 10 and the outer diameter of the lower end cap 30 differ by the width of the outer tube 8 so that the upper end of the upper end of the outer tube 8 is closed. The outer surface of the stopper 10 abuts and is joined, and the lower surface of the outer tube 8 abuts and abuts on the upper side edge of the lower end cap 30.

Here, as shown in Figs. 5 and 6, the inner groove of the lower end end plug 30 in the present embodiment, as shown in Figure 5, 6, the installation groove 37 is formed, the installation groove ( 37, the foreign matter filtration device 50 is provided.

At this time, the foreign substance filtering device 50 is formed in an annular shape, but made of cross-shaped foreign matter filtering pins 51 connected to each other in the vertical and horizontal directions at the center thereof, but the foreign substance filtering device 50 is formed in an annular shape. In addition, it is also possible to be composed of a lattice-like foreign matter filter pin 51 that is connected to a plurality of vertical and horizontal in the center.

In addition, the foreign matter filtering device 50 may be formed of a cross-shaped foreign matter filtering pin 51, the center of which is connected to each other in the vertical and horizontal directions, the foreign matter filtering device 50 in the vertical and horizontal directions It is also possible to consist of a lattice-like foreign matter filter pin 51 is connected to a plurality of central portion.

The foreign matter filtration device 50 installed in the lower end stopper 30 of the annular fuel rod 1 according to the present embodiment is also preferably bonded to the installation groove 37 of the lower end stopper 30 by welding, After forming the installation grooves 37 in the circumferential or helical shape at the inner circumferential edge of the lower end end cap 30 below the main inlet 31, the foreign matter filtration device 50 is coupled to the installation grooves 37. It is also possible to consist of.

On the other hand, the inner and outer periphery of the upper end cap 10 and the lower end cap 30 is formed to be inclined, thereby reducing the fluid resistance of the cooling water introduced to prevent the high temperature generated in the nuclear fuel rod (1) To reduce.

Here, the upper outer coupling groove 15a and the lower outer coupling groove 35a for coupling the nuclear fuel rod handling tool (not shown) in the circumferential direction to the outer circumferential position of the upper end cap 10 and the lower end cap 30. ) Is formed.

In an embodiment of the present invention, the upper and lower outer coupling grooves 15a and 35a are formed to couple and install the nuclear fuel rod handling tool in the circumferential direction at the outer peripheral positions of the upper and lower end caps 10 and 30. However, as shown in FIG. 10, upper and lower inner coupling grooves 15b and 35b for coupling and installing nuclear fuel rod handling tools are formed in the inner circumferential position of the upper and lower end caps 10 and 30. Preferably, the upper and lower inner coupling grooves 15b and 35b are positioned at the upper and lower end caps 10 and 30 of the upper and lower ends of the inner tube 7, respectively. It is preferable that the coupling pieces 13 and 33 are formed in close proximity.

As described above, the upper and lower inner coupling grooves (15b, 35b) is formed on the inner peripheral edges of the upper and lower end caps (10, 30), the lower coupling pieces (13, 33), When the inner tube 7 which is brought into contact with the lower coupling pieces 13 and 33 is extended in the longitudinal direction, the upper and lower end caps 10 and 30 of the upper and lower ends of the inner tube 7 which are in contact with the lower surface of the inner tube 7 are extended. The upper and lower coupling pieces 13 and 33 elastically deform a predetermined portion to fix and support the inner tube 7.

That is, the upper and lower inner coupling grooves 15b and 35b are formed on the inner circumferences of the upper and lower end caps 10 and 30 so that the upper and lower surfaces of the inner and outer tubes 7 and 8 come into contact with each other. By varying the thicknesses of the upper and lower coupling pieces 13 and 33 of the upper and lower end caps 10 and 30 to be welded or electric resistance welded, the inner tube may be subjected to thermal expansion or growth by neutron irradiation in a reactor operating environment. When the longitudinal growth of 7) and the outer tube 8 is different, the phenomenon of the bowing of the annular fuel rod 1 can be alleviated.

In an embodiment of the present invention, the upper and lower inner coupling grooves 15b and 35b are formed on the inner circumferences of the upper and lower end caps 10 and 30, but the inner and inner tubes 7 are formed in close proximity to the inner tube 7. The upper and lower coupling pieces 13 and 33 in contact with the tube 7 are configured to absorb the warpage phenomenon of the nuclear fuel rod 1, but are formed on the outer periphery of the upper and lower end caps 10 and 30. The upper and lower outer coupling grooves 15a and 35a are formed at positions close to the edges of the upper and lower end caps 10 and 30 contacting the upper and lower surfaces of the outer tube 8 to warp the outer tube 8. It is also possible to have a structure that absorbs even the phenomenon.

Hereinafter, a welding method for installing upper and lower end caps of the annular nuclear fuel rod according to the present embodiment will be described.

First, a lower surface of the inner tube 7 is positioned on an upper side of the lower coupling piece 33 of the lower end cap 30, and then an upper surface of the lower coupling piece 33 and a lower surface of the inner tube 7. Weld from outside.

Then, after placing the upper surface of the inner tube (7) on the lower side of the upper coupling piece 13 of the upper end cap 10, the upper surface of the inner tube (7) on the lower side of the upper coupling piece (13) Weld from outside.

At this time, the welding device for welding is preferably made to weld the lower surface of the upper coupling piece 13 and the upper surface of the inner tube 7 after the insertion through the inner channel.

Here, before connecting the upper and lower end caps 10 and 30 to the upper and lower end portions of the inner tube 7 by welding, the annular sintered body 3 is charged to the outer side of the inner tube 7 and then described above. It is also possible to perform a welding operation.

As described above, after connecting the upper and lower end caps 10 and 30 to the upper and lower ends of the inner tube 7 by welding, the outer tube 8 is connected to the upper edge of the lower end cap 30. By positioning the bottom surface of the lower end cap 30 of the upper edge and the outer surface of the outer tube 8 is welded.

At this time, the outer diameter of the lower end cap 30 is made slightly larger than the outer diameter of the upper end cap 10 so that when the outer tube 8 is located at the upper side edge of the lower end cap 30, the outer tube (8) is inserted and positioned through the upper end cap 10.

The upper edge of the lower end cap 30 and the lower surface of the outer tube 8 are welded, and then the outer side of the upper end cap 10 and the inner side of the outer tube 8 are welded.

At this time, as shown in Figures 9 and 10, the upper and lower coupling pieces 13, 33 and inner and outer sides protruding from the lower side and the upper side of the upper and lower end closures 10 and 30, respectively. The portions marked in bold portions at the joints formed on the upper and lower portions of the tubes 7 and 8 and the joints formed on the outer side face the welded portions.

Here, the foreign matter filtration device 50 is coupled to the installation groove 37 of the lower end cap 30, and the welding process is performed by joining each end of the foreign matter filtration device 50 and the installation groove 37 by welding. To complete.

In this embodiment, after the foreign matter filtration device 50 is welded to the lower end cap 30, the upper and lower end caps 10 and 30 are installed on the inner and outer tubes 7 and 8 to annular fuel rods. It is also possible to manufacture and manufacture.

While the exemplary embodiments of the present invention have been described above by way of example, the scope of the present invention is not limited to the specific embodiments, and those skilled in the art are appropriate within the scope described in the claims of the present invention. It will be possible to change.

As described above, the present invention having the configuration as described above has a coupling piece protruding from the lower surface and the upper surface of the upper and lower end caps coupled to the inner tube and the outer tube of the annular nuclear fuel rods, Laser welding of the outer tube from the outside or electric resistance welding makes it easy to manufacture the annular fuel rod, and it is possible to improve the sealing efficiency of the welded part as well as to clean the welded part. When the inflow of the cooling water not only prevents the inflow of foreign matters, the foreign matter filtration device can be installed in a circular groove or a spiral groove, and the effect can be easily installed and manufactured.

Claims (20)

The upper and lower ends of the inner and outer tubes 7 and 8 and the inner and outer tubes 7 and 8 respectively provided in the annular sintered body 3 and the inner and outer peripheries of the sintered body 3, respectively. In the annular fuel rod (1) is provided, including the upper and lower end caps (10, 30) through which the inner channel main outlet (11) and the inner channel main inlet 31 is formed in the center thereof, The upper coupling piece 13 protrudes in the circumferential direction at the center of the lower surface of the inner channel main outlet 11, and the upper coupling piece 13 so that the upper surface of the inner tube 7 is aligned and bonded. The inner joining surface 13a formed inside of) and the outer joining surface 13b formed on the outer side of the upper joining piece 13 so that the upper surface of the outer tube 8 is centered and joined. Having an upper end cap 10; And The lower coupling piece 33 protrudes in the circumferential direction at the center of the upper surface of the inner channel main inlet 31, and the lower coupling piece 33 is aligned so that the lower surface of the inner tube 7 is aligned. The inner joining surface 33a formed inside of) and the outer joining surface 33b formed on the outer side of the lower joining piece 33 so that the lower surface of the outer tube 8 are aligned and bonded to each other. Lower end stopper 30 having; Upper and lower end caps of the annular fuel rod, characterized in that consisting of a configuration comprising a. The method of claim 1, The lower end cap 30 is further configured to further include an installation groove 37 formed on the inner circumference of the lower side of the inner channel main inlet 31, and the foreign matter filtration device 50 coupled to the installation groove 37. Upper and lower end caps of the annular fuel rod. The method of claim 2, The foreign matter filtering device 50 is formed in an annular shape, the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of foreign matter filter pins 51 connected to each other in the vertical and horizontal direction in the center. The method of claim 2, The foreign matter filtering device 50 is formed in an annular shape, the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of a plurality of foreign matter filter pins 51 connected in a grid form vertically and horizontally at the center thereof. The method of claim 2, The foreign material filtering device 50 is the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of foreign matter filter pins 51 connected to each other in the vertical and horizontal direction in the center. The method of claim 2, The foreign material filtering device 50 is the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of a plurality of foreign matter filter pins 51 connected in a grid form vertically and horizontally at the center. The method of claim 2, Upper and lower end caps of the annular fuel rod, characterized in that the installation groove 37 is formed in a columnar or spiral. The method of claim 1, Upper outer coupling grooves 15a and lower outer coupling grooves 35a are formed on the outer circumferential edges of the upper end cap 10 and the lower end cap 30 to engage nuclear fuel rod handling tools in the circumferential direction. Upper and lower end caps of the annular nuclear fuel rods, characterized in that it becomes. The method of claim 1, The upper inner coupling groove 15b and the lower inner coupling groove 35b are formed on the inner circumference of the upper end cap 10 and the lower end cap 30 to engage the nuclear fuel rod handling tool in the circumferential direction. The upper and lower inner coupling grooves 15b and 35b are formed to be adjacent to the inner joining surfaces 13a and 33a of the upper and lower end caps 10 and 30, respectively. End cap. The method of claim 1, Upper and lower end caps of the annular fuel rod, characterized in that the inner and outer edges of the upper end cap 10 and the lower end cap 30 are inclined to reduce fluid resistance of the cooling water. The upper and lower ends of the inner and outer tubes 7 and 8 and the inner and outer tubes 7 and 8 respectively provided in the annular sintered body 3 and the inner and outer peripheries of the sintered body 3, respectively. In the annular fuel rod (1) is provided, including the upper and lower end caps (10, 30) through which the inner channel main outlet (11) and the inner channel main inlet 31 is formed in the center thereof, An upper coupling piece 13 for joining the upper surface of the inner tube 7 to the lower side edge of the inner channel main outlet 11 is protruded, and an outer tube 8 on the outer side thereof. Upper end cap 10 is bonded to the inner side of the; And The lower engaging piece 33 for joining the lower surface of the inner tube 7 to the upper side edge of the inner channel main inlet 31 protrudes, and the lower surface of the outer tube 8 is joined to the edge. Lower end closure 30; Upper and lower end caps of the annular fuel rod, characterized in that consisting of a configuration comprising a. The method of claim 11, The lower end cap 30 is further configured to further include an installation groove 37 formed on the inner circumference of the lower side of the inner channel main inlet 31, and the foreign matter filtration device 50 coupled to the installation groove 37. Upper and lower end caps of the annular fuel rod. The method of claim 12, The foreign matter filtering device 50 is formed in an annular shape, the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of foreign matter filter pins 51 connected to each other in the vertical and horizontal direction in the center. The method of claim 12, The foreign matter filtering device 50 is formed in an annular shape, the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of a plurality of foreign matter filter pins 51 connected in a grid form vertically and horizontally at the center thereof. The method of claim 12, The foreign material filtering device 50 is the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of foreign matter filter pins 51 connected to each other in the vertical and horizontal direction in the center. The method of claim 12, The foreign material filtering device 50 is the upper and lower end caps of the annular nuclear fuel rods, characterized in that consisting of a plurality of foreign matter filter pins 51 connected in a grid form vertically and horizontally at the center. The method of claim 12, Upper and lower end caps of the annular fuel rod, characterized in that the installation groove 37 is formed in a columnar or spiral. The method of claim 11, An upper outer coupling groove 15a and a lower outer coupling groove 35a are formed at the outer circumferential positions of the upper end cap 10 and the lower end cap 30 to allow the nuclear fuel rod handling tool to be coupled in the circumferential direction. Upper and lower end caps of annular fuel rods. The method of claim 11, The upper inner coupling groove 15b and the lower inner coupling groove 35b are formed on the inner circumference of the upper end cap 10 and the lower end cap 30 to engage the nuclear fuel rod handling tool in the circumferential direction. The upper and lower inner coupling grooves 15b and 35b are formed on the upper and lower end caps 10 and 30 of the upper and lower coupling pieces 13 and 33, respectively. Lower end cap. The method of claim 11, Upper and lower end caps of the annular fuel rod, characterized in that the inner and outer edges of the upper end cap 10 and the lower end cap 30 are inclined to reduce fluid resistance of the cooling water.

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