CN218038585U - Fuel rod and fuel assembly - Google Patents

Abstract

The embodiment of the application provides a fuel rod and a fuel assembly. The fuel rod comprises a cladding, wherein a fuel core is arranged inside the cladding; the positioning winding wire is spirally wound on the outer wall of the cladding, the positioning winding wire is provided with a hollow cavity along the axial direction of the positioning winding wire, and the pipe wall of the positioning winding wire is provided with a fluid inlet and a fluid outlet for enabling a coolant to enter and exit the hollow cavity. This application sets up the location wire winding for hollow, have the structure of well plenum chamber to set up fluid inlet and fluid outlet on the pipe wall of location wire winding, satisfying the location function of location wire winding and promoting under the prerequisite of coolant crossing current, make the flow that also has the coolant in the well plenum chamber of location wire winding. The fuel rod that this application provided can improve the heat-carrying ability of coolant and with the cladding between the convective heat transfer ability, reduce the highest temperature of cladding and the position of location wire winding contact, guarantee the security during fuel rod operation better.

Description

Fuel rod and fuel assembly

Technical Field

The present application relates to the field of nuclear fuel assembly safety technology, and more particularly, to a fuel rod and a fuel assembly.

Background

The nuclear energy, as a high-density energy and low-pollution emission energy, has the capability of replacing fossil energy on a large scale and plays an important role in the current world energy structure. However, since the damage of nuclear reaction fuel leakage is irreversible, it is internationally important for the safe operation of nuclear reactors. At present, a plurality of scholars are dedicated to the optimization research of the fuel rod assembly so as to improve the heat exchange performance of the fuel rod assembly and guarantee the stable operation of the nuclear reactor to the maximum extent.

Disclosure of Invention

The present application provides a fuel rod and fuel assembly that at least partially address the above-identified problems of the prior art.

One aspect of the present application provides a fuel rod comprising: the fuel tank comprises a cladding, wherein a fuel core is arranged inside the cladding; the positioning winding wire is spirally wound on the outer wall of the cladding and is provided with a hollow cavity along the axial direction of the positioning winding wire, and a fluid inlet and a fluid outlet for enabling coolant to enter and exit the hollow cavity are formed in the pipe wall of the positioning winding wire.

In some embodiments, the ratio between the thickness of the tube wall of the positioning winding and the inner diameter of the positioning winding ranges from 0.1 to 0.5; a first included angle is formed between the axial direction of the fluid inlet and the axial direction of the hollow cavity, and the first included angle is smaller than 90 degrees; a second included angle is formed between the axial direction of the fluid outlet and the axial direction of the hollow cavity, and the second included angle is smaller than 90 degrees.

In some embodiments, the contour of the fluid inlet and the fluid outlet is an ellipse, and the ratio between the minor axis of the ellipse and the inner diameter of the positioning filament winding ranges from 0.5 to 0.8; the ratio range of the long axis to the short axis of the ellipse is 15-2.

In some embodiments, the sidewalls of the fluid inlet and the fluid outlet are cylindrical.

In some embodiments, a plurality of said fluid inlets and said fluid outlets are arranged in pairs on the wall of said positioning filament winding.

In some embodiments, the dimension between the centre of each fluid inlet and the envelope is greater than or equal to the dimension between the centre of the positioning filament winding and the envelope in the radial direction of the envelope.

In some embodiments, in a radial direction of the enclosure, a dimension between a center of each of the fluid outlets and the enclosure is greater than or equal to a dimension between a center of the positioning wire wrap and the enclosure.

In some embodiments, the distance between the fluid inlets and the fluid outlets provided in pairs gradually decreases in the flow direction of the coolant.

Another aspect of the present application provides a fuel assembly comprising: a core barrel having a containment chamber; a plurality of fuel rods as described above, housed in the housing chamber; and the other spaces in the accommodating cavity except the fuel rods are used for accommodating the coolant, and the coolant is used for carrying away the heat generated by the fuel core.

In some embodiments, a number of the fuel rods are staggered within the containment chamber, and the fluid inlets and the fluid outlets of adjacent fuel rods are staggered.

In the fuel rod provided by at least one embodiment of the present application, the positioning winding wire is set to be a hollow structure having a hollow cavity, and the fluid inlet and the fluid outlet are provided on the tube wall of the positioning winding wire, so that the coolant flows inside the hollow cavity of the positioning winding wire on the premise of satisfying the positioning function of the positioning winding wire and promoting the cross flow of the coolant. Compared with a winding wire of a solid structure in the prior art, the fuel rod provided by the application can improve the heat carrying capacity of the coolant and the heat convection capacity between the fuel rod and the cladding, reduces the highest temperature of the position where the cladding is contacted with the positioning winding wire, and better ensures the safety of the fuel rod during operation.

At least one embodiment of the present application provides a fuel rod in which a fluid inlet and a fluid outlet are obliquely disposed to have a guiding effect on a coolant. The fluid inlet guides the coolant outside the positioning winding wire to enter the hollow cavity, and the fluid outlet guides the coolant in the hollow cavity to flow out of the positioning winding wire, so that more coolant can flow into the hollow cavity, and the heat convection effect is better.

Drawings

Other features, objects, and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, with reference to the accompanying drawings. Wherein:

FIG. 1A is a schematic structural view of a fuel rod according to the prior art;

FIG. 1B is a schematic cross-sectional structure of the structure of FIG. 1A;

FIG. 2A is a schematic structural view of a fuel rod 100 according to one embodiment of the present application;

FIGS. 2B and 2C are enlarged partial views of the section I and II in FIG. 2A, respectively;

FIG. 2D is a schematic diagram of a transverse cross-sectional structure of the structure of FIG. 2A;

FIGS. 2E and 2F are schematic top and bottom views, respectively, of the structure of FIG. 2A;

FIG. 2G is another structural schematic of a fuel rod 100 according to an embodiment of the present application;

FIG. 2H is a schematic diagram of a process of forming a fluid inlet and a fluid outlet according to an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a fuel assembly 1000 according to one embodiment of the present application.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in this specification the expressions first, second, third etc. are only used to distinguish one feature from another, and do not indicate any limitation of features, in particular any precedence order. Thus, a first part discussed in this application may also be referred to as a second part, and vice versa, without departing from the teachings of this application.

In the drawings, the thickness, size and shape of the components have been slightly adjusted for convenience of explanation. The figures are purely diagrammatic and not drawn to scale. As used herein, the terms "approximately", "about" and the like are used as table-approximating terms and not as table-degree terms, and are intended to account for inherent deviations in measured or calculated values that would be recognized by one of ordinary skill in the art.

It will be further understood that terms such as "comprising," "including," "having," "including," and/or "containing" are used throughout this specification to specify the presence of stated features and/or components, but do not preclude the presence or addition of one or more other features, components, and/or groups thereof. Furthermore, when a statement such as "at least one of" appears after a list of listed features, it modifies that entire list of features rather than just individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

In the present application, since the positioning winding is spirally disposed, the axial direction of the positioning winding is a direction parallel to the spiral direction; the radial direction is a direction perpendicular to the axial direction. The radial direction of the cladding is the direction perpendicular to its axis.

Unless otherwise defined, all terms (including engineering and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. In addition, unless explicitly defined or contradicted by context, specific steps included in the methods described herein need not be limited to the order described, but can be performed in any order or in parallel. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.

Further, in this application, when "connected" or "coupled" is used, it may mean either direct contact or indirect contact between the respective components, unless there is an explicit other limitation or can be inferred from the context.

FIG. 1A shows a structural schematic of a fuel rod according to the prior art, and FIG. 1B shows a cross-sectional structural schematic of the structure in FIG. 1A.

As shown in fig. 1A, the prior art fuel rod 1 includes a cladding 11, a fuel core 12, and a wire-wound structure 13. The fuel rod 1 is generally cylindrical, and the wire winding structure 13 is wound on the surface of the cladding 11 of the fuel rod 1 at a constant pitch. The function of the wire winding 13 is to separate a plurality of fuel rods 1 in the radial direction. The wire winding structure 13 has low positioning cost and simple installation and manufacture, and can reduce the mechanical vibration abrasion of grid positioning. In addition, the use of the wire-wound structure 13 can provide structural support to the fuel rod 1 and also promote the lateral flow of the cooling fluid to increase the convective heat transfer coefficient. For example, the coolant can flow through the helical cavities formed by the wire-wound structure 13 of the fuel rods 1, forming a coolant circulation loop that carries away the heat released by the fuel core 12.

However, as shown in fig. 1B, the wire-wound structure 13 is a solid metal structure, and although the conventional wire-wound structure 13 can promote the cross flow of the cooling fluid and increase the convective heat transfer coefficient, the temperature of the contact position between the cladding 11 of the fuel rod 1 and the wire-wound structure 13 is still high. The reason is that when the existing wire winding structure 13 contacts the cladding 11 of the fuel rod 1, a certain included angle is generated, so that flow stagnation is easily generated near the wire winding structure 13, heat generated by the fuel core 12 at the position cannot be transmitted in time, the highest temperature of the surface of the cladding 11 is increased, and the cladding 11 may have a risk of failure under an accident condition, so that the operation risk of the nuclear reactor is increased.

It is therefore necessary to explore how to effectively reduce the maximum temperature at the contact point of the envelope 11 with the filament winding structure 13 due to flow stagnation.

Based on this, a fuel rod according to an embodiment of the present application includes a cladding, a fuel core, and a positioning wrap. A fuel core is disposed inside the cladding. The positioning wire winding is spirally wound on the outer wall of the cladding. The positioning winding wire is provided with a hollow cavity chamber along the axial direction of the positioning winding wire, and a fluid inlet and a fluid outlet for allowing coolant to enter and exit the hollow cavity chamber are arranged on the pipe wall of the positioning winding wire.

In the scheme, the positioning winding wire is of a hollow structure with a hollow cavity, and the pipe wall of the positioning winding wire is provided with the fluid inlet and the fluid outlet, so that the coolant flows in the hollow cavity of the positioning winding wire on the premise of meeting the positioning function of the positioning winding wire and promoting the cross flow of the coolant. Compared with a winding wire of a solid structure in the prior art, the fuel rod provided by the application can improve the heat carrying capacity of the coolant and the heat convection capacity between the fuel rod and the cladding, reduces the highest temperature of the position where the cladding is contacted with the positioning winding wire, and better ensures the safety of the fuel rod during operation.

FIG. 2A shows a structural schematic of a fuel rod 100 according to one embodiment of the present application. Fig. 2B and 2C show partial enlarged views at I and II in fig. 2A, respectively. Fig. 2D shows a cross-sectional structural schematic of the structure in fig. 2A. Fig. 2E and 2F show a top and bottom schematic view, respectively, of the structure in fig. 2A, fig. 2G shows another schematic view of the fuel rod 100, and fig. 2H shows a schematic view of a process of forming the fluid inlet and the fluid outlet according to an embodiment of the present application. An embodiment of the present application will be described in detail with reference to fig. 2A to 2H.

In the embodiment shown in fig. 2A and 2G, the fuel rod 100 includes an upper end plug 110, a lower end plug 120, a cladding 130, and a fuel core 140. The cavity of the cladding 130 is used to accommodate the fuel core 140 and is compressed by the compression spring 160. The both ends of the envelope 130 are connected to the upper end plug 110 and the lower end plug 120, respectively. A positioning wire 150 is wound on the outer wall surface of the envelope 130, that is, the positioning wire 150 is spirally wound on the outer surface of the envelope 130. Optionally, one end of the positioning wire 150 may be fixed to the lower end plug 120 by welding; the other end is fixed to the upper end plug 110 by welding. The connection of the positioning wire wrap 150 to the upper end plug 110 and the lower end plug 120 may also be other fixed connection methods, which are not limited in this application. Furthermore, as shown in the drawing of fig. 2A, only one positioning wire winding 150 is provided as an example, and in other possible embodiments, the number of positioning wire windings 150 is not limited to one.

As shown in fig. 2D, the positioning wire winding 150 has a hollow chamber 152 along the axial direction thereof, and a fluid inlet 154 (shown in fig. 2B) and a fluid outlet 156 (shown in fig. 2C) for allowing the coolant to enter and exit the hollow chamber 152 are provided on the tube wall of the positioning wire winding 150. The coolant may be, for example, a liquid metal (lead or a lead bismuth alloy).

In the above-described aspect, when the coolant flows through the spiral gap formed by the positioning wire windings 150 of the plurality of fuel rods 100, the positioning wire windings 150 form a fluid stagnation region S (see fig. 2D) where they contact the cladding 130 due to the blocking effect of the positioning wire windings 150, and the coolant is reduced in velocity when passing through the fluid stagnation region S, thereby failing to remove heat of the cladding 130 in time. However, since the positioning wire winding 150 of the present application is provided with the fluid inlet 154 and the fluid outlet 156, when the coolant flows near the positioning wire winding 150, a part of the coolant can enter the hollow cavity 152 of the positioning wire winding 150 through the fluid inlet 154, exchange heat with the cladding 130, take away heat from the cladding 130, and flow out of the hollow cavity 152 through the fluid outlet 156, so as to reduce the maximum temperature of the position where the cladding 130 contacts the positioning wire winding 150, effectively improve the safety margin of the maximum temperature limit of the cladding 130, and better ensure the safety of the fuel rod 100 during operation.

In some embodiments, the positioning wire 150 is made of a material having a high strength, such as a zirconium alloy, a tungsten-rhenium alloy, or the like, since the positioning wire 150 provides structural support to the fuel rod 100.

In some embodiments, the positioning wire winding 150 has an outer diameter d and a wall thickness a, i.e., an inner diameter d-2a, and the ratio of the wall thickness a of the positioning wire winding 150 to the inner diameter d-2a of the positioning wire winding 150 ranges from 0.1 to 0.5. A first included angle θ 1 is formed between the axial direction of the fluid inlet 154 and the axial direction of the hollow chamber 152, and the first included angle θ 1 is smaller than 90 °. A second included angle θ 2 is formed between the axial direction of the fluid outlet 156 and the axial direction of the hollow chamber 152, and the second included angle θ 2 is smaller than 90 °.

Optionally, the outer diameter of the positioning winding wire 150 is 1 mm-3 mm, and the wall thickness is 0.2 mm-0.5 mm. The ranges of the first included angle theta 1 and the second included angle theta 2 are both larger than 0 degrees and smaller than 60 degrees.

It should be noted that the outer diameter of the cladding 130, the winding pitch of the positioning wire 150, and other parameters of the present application can refer to the 7-fuel rod model proposed by Pasio, which is not described in detail herein.

In the above solution, since the positioning wire winding 150 has a certain wall thickness, in order to facilitate the flow of the coolant into/out of the hollow chamber 152, the present application further defines that the first included angle θ 1 between the axial direction of the fluid inlet 154 and the axial direction of the hollow chamber 152 is smaller than 90 °. A second included angle θ 2 between the axial direction of the fluid outlet 156 and the axial direction of the hollow chamber 152 is less than 90 °. In other words, the fluid inlet 154 and the fluid outlet 156 have a guiding effect on the coolant. The fluid inlet 154 guides the coolant outside the positioning wire winding 150 to enter the hollow chamber 152, and the fluid outlet 156 guides the coolant inside the hollow chamber 152 to flow out of the positioning wire winding 150, so that more coolant fluid flows into the hollow chamber 152, and the heat convection effect is better.

In some embodiments, the fluid inlet 154 and the fluid outlet 156 have elliptical contours with a ratio between the minor axis of the ellipse and the inner diameter D of the positioning filament winding 150 in the range of 0.5 to 0.8; the ratio range of the long axis to the short axis of the ellipse is 15-2. The sidewalls of the fluid inlet 154 and the fluid outlet 156 are cylindrical. In some embodiments, the fluid inlet 154 and the fluid outlet 156 are contoured by intersecting lines (see fig. 2H) formed by another cylinder M with the positioning wire winding 150 and on the positioning wire winding 150.

As shown in FIG. 2H, assuming the outer diameter of the cladding 130 is D, the pitch of the positioning wire 150 is L, the angle between the axis of the cylinder M and the axis of the positioning wire 150 is β, the radius of the cylinder M is r, and the angle of inclination of the positioning wire 150 is θ, that is

When β satisfies the following formula (1), the fluid inlet 154 and the fluid outlet 156 enable smooth flow of the coolant into/out of the hollow chamber 152.

It should be noted that the included angle β between the axis of the cylinder M and the axis of the positioning filament 150 is the first included angle θ 1 and the second included angle θ 2.

The above arrangement provides better guidance of coolant flow into/out of the hollow chamber 152, thereby improving heat exchange efficiency and reducing the maximum temperature at the point where the cladding 130 contacts the positioning wire wrap 150.

In some embodiments, a plurality of the fluid inlets 154 and the fluid outlets 156 are arranged in pairs on the wall of the positioning wire wrap 150. The greater the number of fluid inlets 154 and fluid outlets 156, the more intense the coolant flow within the positioning wire wrap 150 and the better the heat exchange.

Alternatively, the total number of fluid inlets 154 and fluid outlets 156 in a single pitch of positioning wire wrap 150 may be arranged in eight, i.e., four pairs of fluid inlets 154 and fluid outlets 156. Theoretically, the more the quantity is, the better the heat exchange effect is. However, an excessive number of the fluid inlets 154 and the fluid outlets 156 may increase the difficulty of processing, and the magnitude of the gain may be insignificant.

In some embodiments, the fluid inlet 154 is located close to the last fluid outlet 156, except for the last fluid outlet 156, in the direction of coolant flow, so that coolant can enter the hollow chamber 152 of the positioning wire wrap 150 in time after exiting the last fluid outlet 156.

In some embodiments, the dimension between the center of each fluid inlet 154 and the envelope 130 is greater than or equal to the dimension between the center of the positioning wire wrap 150 and the envelope 130 in the radial direction of the envelope 130.

As described above, due to the blocking effect of the positioning wire winding 150, a fluid stagnation region S is formed near the contact portion of the sheath 130 and the positioning wire winding 150, and therefore, the dimension between the center of the fluid inlet 154 and the sheath 130 is equal to or greater than the dimension between the center of the positioning wire winding 150 and the sheath 130, and the fluid inlet 154 can be formed at a position far away from the fluid stagnation region S, so that a certain flow rate of the coolant entering the hollow cavity 152 can be ensured, the coolant capacity at the fluid stagnation region S can not be affected, the cooling effect of the coolant on the sheath 130 can be ensured, and the purpose of reducing the maximum temperature of the sheath 130 can be finally achieved under the combined action of the coolant at the fluid stagnation region S and the coolant entering the hollow cavity 152 of the positioning wire winding 150.

In some embodiments, the dimension between the center of each of the fluid outlets 156 and the envelope 130 is greater than or equal to the dimension between the center of the positioning wire wrap 150 and the envelope 130 in the radial direction of the envelope 130.

In the same manner as described above, the dimension between the center defining the fluid outlet 156 and the enclosure 130 is greater than or equal to the dimension between the center defining the positioning wire winding 150 and the enclosure 130, so that the fluid outlet 156 is formed at a position far away from the fluid stagnation region S, and the coolant flowing out of the hollow cavity 152 through the fluid outlet 156 is prevented from carrying away the coolant in the fluid stagnation region S, so that the capacity of the coolant in the fluid stagnation region S is not affected, and the cooling effect of the coolant on the enclosure 130 is ensured. In addition, the space inside the hollow chamber 152 of the positioning wire winding 150 is smaller than the space of the spiral gap formed outside the positioning wire winding 150, so that the pressure drop of the coolant passing through the hollow chamber 152 of the positioning wire winding 150 is larger, the velocity of the coolant after flowing out through the fluid outlet 156 is reduced, and the cooling effect is reduced. At this time, the coolant with a relatively high speed in the spiral gap outside the positioning winding 150 is driven to increase the speed, which is advantageous to improve the cooling effect again.

In some embodiments, the distance between the fluid inlets 154 and the fluid outlets 156 arranged in pairs gradually decreases in the direction of flow of the fluid.

In the above solution, since the cooling effect of the coolant is slightly reduced downstream in the flow direction, the fluid inlet 154 and the fluid outlet 156 with a small distance are disposed downstream in the flow direction, which is beneficial for the coolant to flow inside and outside the hollow cavity 152, and improves the convection heat exchange effect.

In some embodiments, the first fluid inlet 154 is located as close as possible to the inlet of the coolant and the last fluid outlet 156 is located as close as possible to the outlet of the coolant in the direction of coolant flow, thereby ensuring that coolant flows at both ends of the positioning wire wrap 150 and preventing localized maximum temperature increases in the jacket 130.

In some embodiments, the fluid inlet 154 is positioned as close as possible to the last fluid outlet 156 in the direction of coolant flow, except for the last fluid outlet 156, so that coolant can enter the hollow chamber 152 of the positioning wire coil 150 in time after flowing out of the last fluid outlet 156, and local maximum temperature increases in the enclosure 130 can be prevented.

To further illustrate the beneficial effects of the present application, the inventors of the present application compared the following examples and found that:

the embodiment of the application compares the convective heat transfer of a single fuel rod 100 with a hollow positioning wire 150 and a fuel bundle with a solid winding positioning structure in a circular flow channel, and under the condition of ensuring that the inlet flow and the temperature are the same, the cladding temperature of the fuel rod is taken as an example, so that the following effects can be achieved: the pressure drop after the improvement is not much (within 1 percent) compared with that before the improvement, but the maximum temperature around the fuel rod cladding is reduced by about 9K, so that the safety of the assembly is improved while the economy is ensured.

Fig. 3 shows a schematic structural diagram of a fuel assembly 1000 according to an embodiment of the present application.

As shown in fig. 3, the fuel assembly 1000 includes a core barrel 200 and a number of fuel rods 100 as described above. The core barrel 200 has a receiving cavity 210. A plurality of fuel rods 100 are accommodated in the accommodation chamber 210; the space in the receiving chamber 210 other than the fuel rods 100 is used to receive the coolant for removing heat generated from the fuel core 140.

In the above-described aspect, when the coolant flows through the spiral gap formed by the positioning wire windings 150 of the plurality of fuel rods 100, the positioning wire windings 150 form a fluid stagnation region S (see fig. 2D) where they contact the cladding 130 due to the blocking effect of the positioning wire windings 150, and the coolant is reduced in velocity when passing through the stagnation region S, thereby failing to timely remove heat from the cladding 130. However, since the positioning wire winding 150 of the present application is provided with the fluid inlet 154 and the fluid outlet 156, when the coolant flows near the positioning wire winding 150, a part of the coolant can enter the hollow cavity 152 of the positioning wire winding 150 through the fluid inlet 154, exchange heat with the cladding 130, take away heat from the cladding 130, and flow out of the hollow cavity 152 through the fluid outlet 156, so as to reduce the maximum temperature of the position where the cladding 130 contacts the positioning wire winding 150, effectively improve the safety margin of the maximum temperature limit of the cladding 130, and better ensure the safety of the fuel assembly 1000 during operation.

In some embodiments, a number of the fuel rods 100 are staggered within the receiving cavity 210, and the fluid inlets 154 and the fluid outlets 156 of adjacent fuel rods 100 are staggered.

The offset distribution of the fluid inlets 154 and fluid outlets 156 can increase turbulence of the coolant within the containment chamber 210, thereby improving convective heat transfer.

The above description is only an embodiment of the present application and an illustration of the technical principles applied. It will be appreciated by a person skilled in the art that the scope of protection covered by the present application is not limited to the embodiments with a specific combination of the features described above, but also covers other embodiments with any combination of the features described above or their equivalents without departing from the technical idea. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims (10)

1. A fuel rod, comprising:

the fuel tank comprises a cladding, wherein a fuel core is arranged inside the cladding;

the positioning winding wire is spirally wound on the outer wall of the cladding and is provided with a hollow cavity along the axial direction of the positioning winding wire, and a fluid inlet and a fluid outlet for enabling coolant to enter and exit the hollow cavity are formed in the pipe wall of the positioning winding wire.

2. The fuel rod of claim 1,

the ratio range of the thickness of the pipe wall of the positioning winding wire to the inner diameter of the positioning winding wire is 0.1-0.5;

a first included angle is formed between the axial direction of the fluid inlet and the axial direction of the hollow cavity, and the first included angle is smaller than 90 degrees;

a second included angle is formed between the axial direction of the fluid outlet and the axial direction of the hollow cavity, and the second included angle is smaller than 90 degrees.

3. The fuel rod of claim 2,

the contour lines of the fluid inlet and the fluid outlet are elliptical, and the ratio range of the minor axis of the ellipse to the inner diameter of the positioning winding wire is 0.5-0.8;

the ratio of the long axis to the short axis of the ellipse ranges from 15 to 2.

4. The fuel rod of claim 2,

the side walls of the fluid inlet and the fluid outlet are cylindrical.

5. The fuel rod of any one of claims 1 to 4,

and a plurality of fluid inlets and fluid outlets are arranged on the tube wall of the positioning winding in pairs.

6. The fuel rod of claim 5,

the dimension between the centre of each fluid inlet and the envelope is greater than or equal to the dimension between the centre of the positioning wire wrap and the envelope in the radial direction of the envelope.

7. The fuel rod of claim 5,

in the radial direction of the envelope, the dimension between the centre of each fluid outlet and the envelope is greater than or equal to the dimension between the centre of the positioning winding and the envelope.

8. The fuel rod of claim 5,

the distance between the fluid inlets and the fluid outlets provided in pairs is gradually reduced in the flow direction of the coolant.

9. A fuel assembly, comprising:

a core barrel having a receiving chamber;

a plurality of fuel rods according to any one of claims 1 to 8, housed in said containment chamber;

and the other spaces in the accommodating cavity except the fuel rods are used for accommodating the coolant, and the coolant is used for carrying away the heat generated by the fuel core.

10. The fuel assembly of claim 9,

the fuel rods are distributed in the accommodating cavity in a staggered mode, and the fluid inlets and the fluid outlets of the adjacent fuel rods are distributed in a staggered mode.

Images