CN218038585U - Fuel rod and fuel assembly - Google Patents

Abstract

Embodiments of the present application provide a fuel rod and a fuel assembly. The fuel rod includes a cladding, and a fuel core is arranged inside the cladding; the positioning winding wire is spirally wound on the outer wall of the cladding, and the positioning winding has a hollow chamber along its axial direction, and the A fluid inlet and a fluid outlet for the coolant to enter and exit the hollow chamber are provided on the tube wall of the positioning winding wire. In this application, the positioning wrapping wire is set as a hollow structure with a hollow chamber, and a fluid inlet and a fluid outlet are arranged on the tube wall of the positioning wrapping wire, under the premise of satisfying the positioning function of the positioning wrapping wire and promoting the cross flow of the coolant , so that there is also a flow of coolant inside the hollow chamber where the winding wire is positioned. The fuel rod provided by this application can improve the heat carrying capacity of the coolant and the convective heat transfer capacity between the cladding and the cladding, reduce the maximum temperature at the position where the cladding is in contact with the positioning winding wire, and better ensure the safety of the fuel rod during operation sex.

Description

A fuel rod and fuel assembly

technical field

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

Background technique

As a high-density energy and low-pollution emission energy, nuclear energy has the ability to replace fossil energy on a large scale, and occupies an important position in the current world energy structure. However, due to the irreversible harm of nuclear reactor fuel leakage, the international community attaches great importance to the safe operation of nuclear reactors. At present, many scholars are devoted to the optimization research of fuel rod assemblies to improve the heat transfer performance of fuel rod assemblies and ensure the stable operation of nuclear reactors to the greatest extent.

Contents of the invention

The present application provides a fuel rod and a fuel assembly that can at least partially solve the above-mentioned problems in the prior art.

One aspect of the present application provides a fuel rod, including: a cladding, a fuel core is arranged inside the cladding; a positioning winding wire is spirally wound on the outer wall of the cladding, and the positioning winding wire has a A hollow chamber in the axial direction, and the tube wall of the positioning wrapping wire is provided with a fluid inlet and a fluid outlet for the coolant to enter and exit the hollow chamber.

In some embodiments, the ratio between the thickness of the tube wall of the positioning wrapping wire and the inner diameter of the positioning wrapping wire ranges from 0.1 to 0.5; the axial direction of the fluid inlet and the axial direction of the hollow chamber There is a first included angle between them, and the first included angle is less than 90°; there is a second included angle between the axial direction of the fluid outlet and the axial direction of the hollow chamber, and the second included angle is smaller than 90° °.

In some embodiments, the contour lines of the fluid inlet and the fluid outlet are elliptical, and the ratio between the minor axis of the ellipse and the inner diameter of the positioning winding wire is 0.5-0.8; the ellipse The ratio of the major axis to the minor axis of the shape ranges from 15 to 2.

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

In some embodiments, several fluid inlets and fluid outlets are arranged in pairs on the tube wall of the positioning wrapping wire.

In some embodiments, in the radial direction of the casing, the dimension between the center of each of the fluid inlets and the casing is greater than or equal to the distance between the center of the positioning wrapping wire and the casing room size.

In some embodiments, in the radial direction of the casing, the dimension between the center of each of the fluid outlets and the casing is greater than or equal to the distance between the center of the positioning wrapping wire and the casing. room size.

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

Another aspect of the present application provides a fuel assembly, including: a core barrel with a containing chamber; several fuel rods as described above, housed in the containing chamber; The other space outside is used to accommodate the coolant, and the coolant is used to take away the heat generated by the fuel core.

In some embodiments, several fuel rods are distributed in a dislocation in the accommodation chamber, and the fluid inlets and the fluid outlets of adjacent fuel rods are distributed in a dislocation.

In the fuel rod provided by at least one embodiment of the present application, the positioning wrapping wire is set as a hollow structure with a hollow chamber, and a fluid inlet and a fluid outlet are arranged on the tube wall of the positioning wrapping wire. Under the premise of function and promotion of cross flow of coolant, the flow of coolant also exists inside the hollow chamber where the winding wire is positioned. Compared with the solid-structure wrapping wire in the prior art, the fuel rod provided by the present application can improve the heat carrying capacity of the coolant and the convective heat transfer capability between the cladding and the cladding, and reduce the contact position between the cladding and the positioning wrapping wire The highest temperature can better ensure the safety of fuel rods during operation.

In the fuel rod provided by at least one embodiment of the present application, the fluid inlet and the fluid outlet are arranged obliquely to guide the coolant. The fluid inlet guides the coolant outside the positioning wire to enter the hollow chamber, and the fluid outlet guides the coolant in the hollow chamber to flow out to the outside of the positioning wire, which is conducive to more coolant fluid flowing into the hollow chamber, and the convective heat transfer effect is better it is good.

Description of drawings

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

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

Fig. 1B is a cross-sectional schematic diagram of the structure in Fig. 1A;

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

Fig. 2B and Fig. 2C are respectively the partial enlarged view of I place and II place in Fig. 2A;

Figure 2D is a schematic diagram of a transverse cross-sectional structure of the structure in Figure 2A;

Fig. 2E and Fig. 2F are respectively the top view structure schematic diagram and the bottom view structure schematic diagram of the structure in Fig. 2A;

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

2H is a schematic diagram of the formation process of 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 an embodiment of the present application.

detailed description

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are descriptions of exemplary embodiments of the application only, and are not intended to limit the scope of the application in any way. Throughout the specification, the same reference numerals refer to the same elements. 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, expressions such as first, second, third, etc. are only used to separate one feature from another feature area, and do not represent any limitation on the features, especially do not represent any sequential order. Accordingly, a first part discussed in this application could also be termed a second part, and vice versa, without departing from the teachings of this application.

In the drawings, the thickness, size and shape of components have been slightly adjusted for convenience of illustration. The drawings are examples only and are not strictly drawn to scale. As used herein, the words "approximately," "approximately," and similar words are used as words of approximation, not of degree, and are intended to describe measurements that would be recognized by those of ordinary skill in the art. Or inherent bias in calculated values.

It should also be understood that expressions such as "comprises", "comprises", "has", "comprises" and/or "comprising" in this specification are open rather than closed expressions, which mean that there are all The stated features and/or components do not exclude the presence of one or more other features, components and/or combinations thereof. Furthermore, expressions such as "at least one of," when preceding a list of listed features, modify the entire list of features and do not modify just the individual elements of the list. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". Also, the word "exemplary" is intended to mean an example or illustration.

In the present application, since the positioning winding wire is arranged helically, the axial direction of the positioning winding wire is a direction parallel to the helical 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 terms and scientific and technical terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It should also be understood that unless expressly stated in this application, words defined in commonly used dictionaries should be interpreted to have a meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or Overly formal interpretation of meaning.

It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. In addition, unless explicitly defined or contradicted by the context, the specific steps included in the methods described in the present application are not necessarily limited to the recited order, but may be performed in any order or in parallel. The present application will be described in detail below with reference to the accompanying drawings and embodiments.

In addition, when "connected" or "coupled" is used in the present application, it may indicate that the corresponding parts are in direct contact or indirect contact, unless there is a clear other limitation or it can be deduced from the context.

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

As shown in FIG. 1A , a fuel rod 1 in the prior art includes a cladding 11 , a fuel core 12 and a wire wrapping structure 13 . The fuel rod 1 is cylindrical as a whole, and the wire wrapping structure 13 is wound on the surface of the cladding 11 of the fuel rod 1 according to a fixed pitch. The function of the wire wrapping structure 13 is to separate a plurality of fuel rods 1 in the radial direction. The positioning cost of the above-mentioned wire winding structure 13 is low, the installation and manufacture are simple, and the mechanical vibration and abrasion of the grid positioning can be reduced. In addition, the use of the wire wrapping structure 13 can not only provide structural support for the fuel rod 1, but also promote the lateral flow between cooling fluids to improve the convective heat transfer coefficient. For example, the coolant can flow through the spiral cavities formed by the wire-wound structures 13 of several fuel rods 1 to form a coolant circulation loop and take 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. Although the existing wire-wound structure 13 can promote the cross flow of cooling fluid and improve the convective heat transfer coefficient, the cladding 11 of the fuel rod 1 and the wire-wound The temperature at the contact position of structure 13 is still high. This is due to the fact that a certain angle will be generated when the existing wire wrapping structure 13 is in contact with the cladding 11 of the fuel rod 1, resulting in flow stagnation easily occurring near the wire wrapping structure 13, so that the heat generated by the fuel core 12 there cannot be timely In turn, the maximum temperature of the surface of the cladding 11 rises, so that the cladding 11 may have a risk of failure under accident conditions, thereby increasing the operational risk of the nuclear reactor.

Therefore, it is necessary to explore how to effectively reduce the maximum temperature at the contact portion between the cladding 11 and the winding wire 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 wire. A fuel core is disposed inside the cladding. The positioning wrapping wire is helically wound on the outer wall of the casing. The positioning winding wire has a hollow chamber along its axial direction, and the tube wall of the positioning winding wire is provided with a fluid inlet and a fluid outlet for allowing coolant to enter and exit the hollow chamber.

In the above scheme, the positioning winding wire is set as a hollow structure with a hollow chamber, and a fluid inlet and a fluid outlet are arranged on the tube wall of the positioning winding wire, in order to satisfy the positioning function of the positioning winding wire and promote the coolant cross flow On the premise, the flow of coolant also exists inside the hollow chamber where the winding wire is positioned. Compared with the solid-structure wrapping wire in the prior art, the fuel rod provided by the present application can improve the heat carrying capacity of the coolant and the convective heat transfer capability between the cladding and the cladding, and reduce the contact position between the cladding and the positioning wrapping wire The highest temperature can better ensure the safety of fuel rods during operation.

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

In the embodiment shown in FIG. 2A and FIG. 2G , the fuel rod 100 includes an upper end plug 110 , a lower end plug 120 , a cladding 130 , and a fuel core 140 . Wherein, the cavity of the cladding 130 is used to accommodate the fuel core 140 and is compressed by the compression spring 160 . Both ends of the shell 130 are connected to the upper plug 110 and the lower plug 120 respectively. A positioning winding wire 150 is wound on the outer wall surface of the casing 130 , that is, the positioning winding wire 150 is spirally wound on the outer surface of the casing 130 . Optionally, one end of the positioning wire 150 can be fixed on the lower end plug 120 by welding; the other end can be fixed on the upper end plug 110 by welding. The connection method between the positioning winding wire 150 and 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. Moreover, as shown in FIG. 2A , only one positioning winding wire 150 is set as an example, and in other feasible implementation manners, the number of positioning winding wires 150 is not limited to one.

As shown in FIG. 2D, the positioning winding wire 150 has a hollow chamber 152 along its axial direction, and the tube wall of the positioning winding wire 150 is provided with a fluid for allowing the coolant to enter and exit the hollow chamber 152. Inlet 154 (shown with reference to FIG. 2B ) and fluid outlet 156 (shown with reference to FIG. 2C ). The coolant can be, for example, liquid metal (lead or lead-bismuth alloy).

In the above solution, when the coolant flows through the spiral gap formed by the positioning winding wires 150 of several fuel rods 100, due to the blocking effect of the positioning winding wires 150, a fluid stagnation area is formed at the position where the positioning winding wires 150 and the cladding 130 are in contact. S (refer to FIG. 2D ), the speed of the coolant decreases when flowing through the fluid stagnation area S, and the heat of the cladding 130 cannot be taken away in time. However, since the positioning winding 150 of the present application is provided with a fluid inlet 154 and a fluid outlet 156, when the coolant flows near the positioning winding 150, part of the coolant can enter the hollow cavity of the positioning winding 150 through the fluid inlet 154 In the chamber 152, it exchanges heat with the cladding 130, takes away the heat of the cladding 130, and then flows out from the hollow chamber 152 through the fluid outlet 156, thereby reducing the maximum temperature of the position where the cladding 130 is in contact with the positioning winding wire 150 , which can effectively increase 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, since the positioning wrapping wire 150 can provide structural support for the fuel rod 100 , the material of the positioning wrapping wire 150 should have relatively high strength, for example, zirconium alloy, tungsten-rhenium alloy, and the like.

In some embodiments, the outer diameter of the positioning wrapping wire 150 is d, the thickness of the tube wall is a, that is, the inner diameter is d-2a, the thickness a of the tube wall of the positioning wrapping wire 150 is the same as the inner diameter of the positioning wrapping wire 150 The ratio between d-2a ranges from 0.1 to 0.5. There is a first included angle θ1 between the axial direction of the fluid inlet 154 and the axial direction of the hollow chamber 152 , and the first included angle θ1 is less than 90°. There is a second included angle θ2 between the axial direction of the fluid outlet 156 and the axial direction of the hollow chamber 152 , and the second included angle θ2 is less than 90°.

Optionally, the outer diameter of the positioning wrap 150 is 1 mm to 3 mm, and the wall thickness is 0.2 mm to 0.5 mm. The ranges of the first included angle θ1 and the second included angle θ2 are both larger than 0° and smaller than 60°.

It should be noted that parameters such as the outer diameter of the cladding 130 and the winding pitch of the positioning wrapping wire 150 in the present application can refer to the 7-fuel rod model proposed by Pasio, which will not be repeated in the present application.

In the above solution, since the positioning wire 150 has a certain wall thickness, in order to facilitate the flow of coolant into/out of the hollow chamber 152, the present application further defines the axial direction of the fluid inlet 154 and the axial direction of the hollow chamber 152 The first included angle θ1 between them is less than 90°. A second included angle θ2 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 guide the coolant. The fluid inlet 154 guides the coolant outside the positioning winding 150 into the hollow chamber 152, and the fluid outlet 156 guides the coolant in the hollow chamber 152 to flow out to the outside of the positioning winding 150, which is beneficial for more coolant fluid to flow into the hollow chamber Inside the 152, convection heat transfer is better.

In some embodiments, the contour lines of the fluid inlet 154 and the fluid outlet 156 are elliptical, and the ratio between the minor axis of the ellipse and the inner diameter D of the positioning winding wire 150 is in the range of 0.5-0.8 ; The ratio of the major axis to the minor axis of the ellipse is 15-2. The side walls of the fluid inlet 154 and the fluid outlet 156 are cylindrical. In some embodiments, the contours of the fluid inlet 154 and the fluid outlet 156 are formed by another cylinder M intersecting the positioning winding wire 150 and forming an intersecting line on the positioning winding wire 150 (refer to FIG. 2H ). .

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

When β satisfies the following formula ①, the fluid inlet 154 and the fluid outlet 156 can make the coolant flow into/out of the hollow chamber 152 smoothly.

It should be noted that the above-mentioned angle β between the axis of the cylinder M and the axis of the positioning winding wire 150 is the aforementioned first included angle θ1 and the aforementioned second included angle θ2.

The above solution can better guide the coolant to flow into/out of the hollow chamber 152 , thereby improving the heat exchange efficiency and reducing the maximum temperature at the position where the cladding 130 is in contact with the positioning winding wire 150 .

In some embodiments, several fluid inlets 154 and fluid outlets 156 are provided in pairs on the tube wall of the positioning wrapping wire 150 . The more the number of the fluid inlets 154 and the fluid outlets 156 are, the more intense the flow of the coolant in the positioning wire 150 is, and the better the heat exchange effect is.

Optionally, the total number of the fluid inlets 154 and the fluid outlets 156 within a single pitch of the positioning winding 150 is set to eight, that is, four pairs of the fluid inlets 154 and the fluid outlets 156 . In theory, the more the number, the better the heat transfer effect. However, too many fluid inlets 154 and fluid outlets 156 may increase processing difficulty, and the gain is not obvious.

In some embodiments, in the flow direction of the coolant, except for the last fluid outlet 156, the fluid inlet 154 is close to the previous fluid outlet 156, so that the coolant can flow out of the last fluid outlet 156 in time. Access to the interior of the hollow chamber 152 where the wrapping wire 150 is positioned.

In some embodiments, in the radial direction of the casing 130, the dimension between the center of each fluid inlet 154 and the casing 130 is greater than or equal to the center of the positioning wrapping wire 150 and the center of the casing 130. The size between the shells 130 described above.

As mentioned above, due to the blocking effect of the positioning winding wire 150, a fluid stagnation area S will be formed near the position where the casing 130 contacts the positioning winding wire 150. Therefore, the center between the fluid inlet 154 and the casing 130 is defined The size is greater than or equal to the size between the center of the positioning winding 150 and the casing 130, so that the fluid inlet 154 can be formed at a position away from the fluid stagnation area S, and the coolant entering the hollow chamber 152 can be ensured to have A certain flow rate will not affect the capacity of the coolant located in the fluid stagnation area S at the same time, so as to ensure the cooling effect of this part of the coolant on the cladding 130, so that the coolant in the fluid stagnation area S enters the positioning winding 150 The purpose of reducing the maximum temperature of the cladding shell 130 is finally achieved under the joint action of the coolant inside the hollow chamber 152 .

In some embodiments, in the radial direction of the casing 130, the dimension between the center of each fluid outlet 156 and the casing 130 is greater than or equal to the center of the positioning wrapping wire 150 and the center of the casing 130. The size between the shells 130 described above.

In the same way as above, the size between the center of the fluid outlet 156 and the casing 130 is defined to be greater than or equal to the size between the center of the positioning wrapping wire 150 and the casing 130, so that the fluid outlet 156 can be formed far away from the casing 130. The position of the fluid stagnation area S is to prevent the coolant flowing out of the hollow chamber 152 through the fluid outlet 156 from taking the coolant in the fluid stagnation area S away, thereby not affecting the capacity of the coolant in the fluid stagnation area S, and ensuring this part The cooling effect of the coolant on the cladding 130 . In addition, compared with the space size of the spiral gap formed outside the positioning winding wire 150, the internal space of the hollow chamber 152 of the positioning winding wire 150 is relatively small, therefore, when the coolant passes through the hollow chamber 152 of the positioning winding wire 150 The pressure drop is relatively large, the velocity of the fluid flowing out through the outlet 156 is also reduced, and the cooling effect is reduced. At this time, driven by the faster coolant located in the helical gap outside the positioning winding 150, increasing its velocity is beneficial to improve the cooling effect again.

In some embodiments, the distance between the paired fluid inlets 154 and the fluid outlets 156 decreases gradually along the flow direction of the fluid.

In the above solution, since the cooling effect of the coolant is slightly lowered downstream in the flow direction, the fluid inlet 154 and the fluid outlet 156 with smaller spacings are arranged downstream in the flow direction to facilitate the flow of the coolant inside and outside the hollow chamber 152 , improve convective heat transfer effect.

In some embodiments, in the flow direction of the coolant, the first fluid inlet 154 should be as close as possible to the coolant inlet, and the last fluid outlet 156 should be as close as possible to the coolant outlet, so that the position of the winding wire 150 can be ensured. There is also coolant flow at both ends, preventing a local maximum temperature rise in the cladding 130 .

In some embodiments, in the flow direction of the coolant, except for the last fluid outlet 156, the fluid inlet 154 is as close as possible to the previous fluid outlet 156, so that the coolant can flow out from the last fluid outlet 156. Timely access to the interior of the hollow chamber 152 where the winding wire 150 is positioned can also prevent the local maximum temperature of the cladding 130 from rising.

In order to further illustrate the beneficial effects of the present application, the inventor of the present application finds after comparing the following examples:

The embodiment of the present application compares the convective heat transfer between a single fuel rod 100 with a hollow positioning winding wire 150 and a fuel rod bundle with a solid winding positioning structure in a circular flow channel. Under the condition that the inlet flow rate and temperature are the same , taking the cladding temperature of the fuel rod as an example, the following effects can be achieved: the pressure drop after the improvement is not much different from that before the improvement (within 1%), but the maximum temperature around the cladding of the fuel rod is reduced by about 9K. At the same time, it also improves the safety of components.

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 several fuel rods 100 as described above. The core barrel 200 has an accommodation chamber 210 . Several fuel rods 100 are accommodated in the accommodation chamber 210; other spaces in the accommodation chamber 210 except the fuel rods 100 are used to accommodate the coolant, and the coolant is used to take away the The heat generated by the fuel core 140 .

In the above solution, when the coolant flows through the spiral gap formed by the positioning winding wires 150 of several fuel rods 100, due to the blocking effect of the positioning winding wires 150, a fluid stagnation area is formed at the position where the positioning winding wires 150 and the cladding 130 are in contact. S (refer to FIG. 2D ), the speed of the coolant decreases when flowing through the stagnant region S, and the heat of the cladding 130 cannot be taken away in time. However, since the positioning winding 150 of the present application is provided with a fluid inlet 154 and a fluid outlet 156, when the coolant flows near the positioning winding 150, part of the coolant can enter the hollow cavity of the positioning winding 150 through the fluid inlet 154 In the chamber 152, it exchanges heat with the cladding 130, takes away the heat of the cladding 130, and then flows out from the hollow chamber 152 through the fluid outlet 156, thereby reducing the maximum temperature of the position where the cladding 130 is in contact with the positioning winding wire 150 , which can effectively increase 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, several fuel rods 100 are distributed in a staggered manner in the accommodation chamber 210 , and the fluid inlets 154 and the fluid outlets 156 of adjacent fuel rods 100 are distributed in a staggered manner.

The dislocation distribution of the fluid inlet 154 and the fluid outlet 156 can increase the turbulence of the coolant in the accommodation chamber 210 , thereby improving the convective heat transfer effect.

The above description is only an implementation of the present application and an illustration of the applied technical principle. Those skilled in the art should understand that the scope of protection involved in this application is not limited to the technical solution formed by the specific combination of the above-mentioned technical features, and should also cover the technical solutions obtained by the above-mentioned technical features or other technical solutions without departing from the technical concept. Other technical solutions formed by any combination of equivalent features. For example, a technical solution formed by replacing the above-mentioned features with technical features with similar functions disclosed in (but not limited to) this 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.

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