CN117766165A - Reactor core fuel element and heat pipe cooling reactor with radial extraction heat pipe - Google Patents

Abstract

The invention provides a reactor core fuel element and a heat pipe cooling reactor with radial leading-out heat pipes. The core fuel elements are used for forming core fuel, and the core fuel is used for forming a heat pipe cooling reactor; the reactor core fuel elements are divided into a reactor core fuel element segments along the axis; each reactor core fuel element segment is provided with an axial heat pipe channel; in addition to the core fuel element segments at the head and tail ends, each core fuel element segment is radially provided with a radial heat pipe extraction channel. The axial heat pipe channel and the radial heat pipe leading-out channel both accommodate the heat pipe; according to the invention, the straight heat pipe and the bent heat pipe are matched with the axial heat pipe channels and the radial heat pipe leading-out channels, so that a plurality of heat pipes can be arranged in each axial heat pipe channel in the reactor core fuel element, and further, the heat exchange effect of a single reactor core fuel element is improved, and the overall heat exchange efficiency of the heat pipe cooling reactor is improved.

Description

Core fuel elements and heat pipe cooling reactor with radially led heat pipes

Technical field

The present invention relates to the field of heat exchange design, and in particular, to a core fuel element and a heat pipe cooling reactor with a radially drawn heat pipe.

Background technique

With the popularization of nuclear energy technology applications, the demand for heat pipe-cooled reactors is developing towards high power. However, current heat pipe stacks all adopt the solution of inserting and extracting straight heat pipes along the axial direction of the reactor core, whether it is inserted on one side (as shown in Figure 1), inserted in a staggered position on both sides (as shown in Figure 2), or inserted on both sides (as shown in Figure 2) 3) Only one or two heat pipes can be arranged in each axial heat pipe channel in the reactor core. Due to the current limited heat exchange capacity of a single heat pipe, it is difficult to provide sufficient cooling effect, resulting in the power of the heat pipe cooling reactor being greatly limited. , hindering the smooth development of high-power heat pipe stacks.

Contents of the invention

In view of the deficiencies in the prior art, the object of the present invention is to provide a heat pipe cooling reactor with a radially led heat pipe.

According to a core fuel element provided by the present invention, the core fuel element is used to constitute a core fuel, and the core fuel is used to constitute a heat pipe cooling reactor;

The core fuel elements are divided into a core fuel element segments along the axis; a is greater than 2;

One or more axial heat pipe channels are provided in each core fuel element segment; the axial heat pipe channels in adjacent core fuel element segments correspond one to one, and the corresponding axial heat pipe channels are connected;

In addition to the core fuel element segments located at the front and rear ends, each core fuel element segment also has radial heat pipe lead-out channels along the radial direction. The number of core fuel element segments with radial heat pipe lead-out channels is a. -2; the axial heat pipe channel in the core fuel element segment corresponds to the radial heat pipe lead-out channel in the core fuel element segment, and the corresponding axial heat pipe channel is connected to the radial heat pipe lead-out channel Pass;

The axial heat pipe channel and the radial heat pipe lead-out channel both accommodate the heat pipe;

Each heat pipe has one end located in the axial heat pipe channel and the other end located outside the core fuel element.

Preferably, each core fuel element segment is provided with an axial heat pipe channel; the axial heat pipe channels in adjacent core fuel element segments are connected in sequence to form an axial heat pipe channel in the core fuel element;

Each core fuel element segment is provided with a heat pipe.

Preferably, the heat pipe includes a straight heat pipe and a bent heat pipe;

Direct heat pipes are provided in the axial heat pipe channels in the core fuel element segments at both ends; one end of the direct heat pipe is installed in the axial heat pipe channel in the core fuel element segment, and the other end extends out of the axial heat pipe channel ;

A bent heat pipe is provided in the axial heat pipe channel in the core fuel element segment of the remaining core segments; one end of the bent heat pipe is located in the axial heat pipe channel, and the other end extends in the direction of the radial heat pipe lead-out channel, and Extending to the outside of the radial heat pipe lead-out channel.

Preferably, the number of the core fuel element segments is 5, which are respectively the first core fuel element segment, the second core fuel element segment, the third core fuel element segment, and the fourth core fuel element segment. Fuel element segments and the fifth core fuel element segment; the five core fuel element segments are arranged in sequence;

A direct heat pipe is arranged in each of the first core fuel element segment and the fifth core fuel element segment;

A bent heat pipe is arranged in the second core fuel element segment, the third core fuel element segment and the fourth core fuel element segment.

Preferably, the number of heat pipes in a core fuel element is N. At a given heat pipe operating temperature, when the average heat pipe heat transfer efficiency in the channel is equal to the boiling limit heat transfer efficiency, N is optimal. At this time, the reactor core The heat pipe channel of the fuel element has the highest heat exchange efficiency.

A heat pipe cooling reactor with radially led heat pipes provided by the present invention includes a core fuel, and the core fuel is composed of a plurality of core fuel elements arranged in parallel; the core fuel element is the core fuel element.

Preferably, there is no axial position section in the heat pipe cooling reactor: the bent heat pipes in this section are all led out in the radial direction at this section.

Preferably, the bent heat pipes exported at the same axial position are exported in a layered superposition mode.

Preferably, the layered superposition mode is: from the side view angle, the outlets of multiple radial heat pipe lead-out channels at the same axial position are arranged in layers, and each layer is arranged with several outlets of the radial heat pipe lead-out channels. stacked arrangement.

Compared with the prior art, the present invention has the following beneficial effects:

The present invention uses core fuel elements to form core fuel, and then uses the core fuel to form a heat pipe to cool the reactor, in which a radial heat pipe lead-out channel is provided in the core fuel element; the present invention combines straight heat pipes and bent heat pipes with axial The arrangement of heat pipe channels and radial heat pipe lead-out channels allows multiple heat pipes to be arranged in each axial heat pipe channel in the core fuel element, thereby improving the heat exchange effect of a single core fuel element and allowing the heat pipes to cool the overall reactor Heat exchange efficiency is improved.

Description of drawings

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

Figure 1 is a schematic structural diagram of a single-side insertion solution in the prior art;

Figure 2 is a schematic structural diagram of a two-side dislocation insertion scheme in the prior art;

Figure 3 is a schematic structural diagram of the two-side pair insertion solution in the prior art;

Figure 4 is a structural view of the core fuel element of the present invention;

Figure 5 is a schematic cross-sectional structural diagram of the axial position of the core fuel of the present invention;

Figure 6 is a schematic structural diagram of the heat pipe cooling reactor of the present invention, which mainly reflects the arrangement of the heat pipes;

Figure 7 is a schematic structural diagram of the heat pipe cooling reactor of the present invention embodying the layered superposition mode;

Figure 8 is a schematic diagram of the heat pipe structure;

Figure 9 is a schematic diagram of the relationship between the heat transfer limit of the heat pipe and the operating temperature of the heat pipe.

Figure 10 is a schematic diagram showing the relationship between the heat exchange efficiency of the heat pipe channel and the number of inserted heat pipes.

The figure shows:

Detailed ways

The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

The invention provides a core fuel element, the core fuel element 10 is used to constitute the core fuel 1, and the core fuel 1 is used to constitute a heat pipe cooling reactor;

The core fuel element 10 is divided into a core fuel element segments 11 along the axis; a is greater than 2;

Each core fuel element segment 11 is provided with one or more axial heat pipe channels. Preferably, as shown in Figure 4, each core fuel element segment 11 is provided with only one axial heat pipe channel. Each core fuel element segment 11 is provided with one heat pipe 2 , that is, the number a of the core fuel element segment 11 is the same as the number of heat pipes 2 in the core fuel element 10 . The axial heat pipe channels in adjacent core fuel element segments 11 correspond one to one, and the corresponding axial heat pipe channels are connected; that is, the axial heat pipe channels in adjacent core fuel element segments 11 are connected in sequence, An axial heat pipe channel in the core fuel element 10 is formed.

In addition to the core fuel element segments 11 located at both ends, each core fuel element segment 11 is also provided with a radial heat pipe lead-out channel in the radial direction, that is, the core fuel element is located in the middle of the core fuel element segments 11 at both ends. The element block 11 is provided with a radial heat pipe lead-out channel along the radial direction. The number of core fuel element segments 11 with radial heat pipe lead-out channels is a-2; the axial heat pipe channel in the core fuel element segment 11 and the radial heat pipe lead-out in the core fuel element segment 11 The channels correspond one to one, and the corresponding axial heat pipe channels are connected with the radial heat pipe lead-out channels;

The axial heat pipe channel and the radial heat pipe lead-out channel both accommodate the heat pipes 2; each heat pipe 2 has one end located in the axial heat pipe channel and the other end located outside the core fuel element 10.

The heat pipe 2 includes a straight heat pipe 21 and a bent heat pipe 22; only straight heat pipes 21 are provided in the axial heat pipe channels in the core fuel element segments 11 at both ends. One end of the direct heat pipe 21 is installed in the axial heat pipe channel in the core fuel element block 11, and the other end extends out of the axial heat pipe channel. Only the bent heat pipe 22 is provided in the axial heat pipe channel in the core fuel element segment 11 of the remaining core segments; one end of the bent heat pipe 22 is located in the axial heat pipe channel, and the other end leads to the radial heat pipe channel. direction, and extends to the outside of the radial heat pipe lead-out channel to extend out of the core fuel element 10 .

In a preferred example, referring to Figures 4 and 6, the number of the core fuel element segments 11 is 5, which are the first core fuel element segment 111, the second core fuel element segment 112, The third core fuel element segment 113, the fourth core fuel element segment 114 and the fifth core fuel element segment 115; the five core fuel element segments 11 are arranged in sequence;

A direct heat pipe 21 is arranged in each of the first core fuel element segment 111 and the fifth core fuel element segment 115; the second core fuel element segment 112, the third core fuel element segment 113 and A bent heat pipe 22 is arranged in each of the fourth core fuel element segments 114 .

That is, for the core fuel element 10, two straight heat pipes 21 are arranged on both sides of a single axial heat pipe channel of the core fuel element 10, and three bent heat pipes 22 are arranged inside the axial heat pipe channel. The bent heat pipes One part of 22 is arranged in the axial heat pipe channel along the axial direction, and the other part is bent and led out of the core fuel element 10 along the radial heat pipe lead-out channel of the core fuel element 10. Among them, there is one straight heat pipe 21 and three bent heat pipes 22. , and a straight heat pipe 21 are arranged in sequence. The evaporation sections of the above five heat pipes fill the axial heat pipe channel of the core fuel element 10 in turn. The heat of the core fuel element 10 is led from the evaporation section of the heat pipe to the condensation section of the heat pipe. , the heat in the straight heat pipe 21 is led out in the axial direction, and the bent heat pipe 22 is turned and led out in the radial direction at the core fuel element segment. In this way, for the core fuel element 10, more than 2 heat pipes can be continuously arranged in the axial heat pipe channel of a complete core fuel element 10, and the number of heat pipes can be increased or decreased according to the core power, effectively enhancing the power inside the reactor. The total number of heat pipes ensures the effective implementation of high-power heat pipe stacks.

The number of heat pipes 2 in a core fuel element 10 is N. At a given heat pipe operating temperature, the total heat transfer amount in a heat pipe channel will increase as the number of heat pipes increases, and the heat pipe boiling heat transfer The limit will decrease as the number of heat pipes increases. When the average heat pipe heat transfer efficiency in the channel is equal to the boiling limit heat transfer efficiency, N is optimal. At this time, the heat pipe channel heat transfer efficiency of the core fuel element is the highest. Specifically, as shown in Figure 9, in the axial heat pipe channel of a core fuel element 10 of a given power and length, when a heat pipe is inserted, generally speaking, the heat transfer power of the heat pipe is affected by its operation. The corresponding heat transfer limit limits at temperature are shown as solid lines in Figure 9, such as entrainment limit, capillary limit, etc. If the material temperature and operating conditions permit, the operating temperature of the heat pipe can be increased to increase the heat transfer limit, thereby ultimately improving the heat pipe heat transfer efficiency of the heat pipe.

At a given operating temperature of the heat pipe, the heat transfer power of a single heat pipe is limited by the corresponding heat transfer limit. It should be noted that except for the boiling limit which is proportional to the length of the evaporation section of the heat pipe, the other limits have nothing to do with the length of the evaporation section of the heat pipe. Or inversely proportional; because in most heat pipe operating conditions, the heat pipe temperature does not reach the area dominated by the boiling limit. Therefore, by placing two or more heat pipes in a single axial heat pipe channel of the core fuel element 10, the evaporation section of these heat pipes is shortened relative to the evaporation section of a single heat pipe, but the corresponding heat transfer limit is It can increase slightly, that is, the average heat transfer efficiency of multiple heat pipes can be greater than the heat transfer efficiency under the condition of a single tube, thereby improving the overall heat transfer efficiency of the channel.

However, it should be noted that the number n of multiple heat pipes will be limited by the boiling limit. As mentioned above, the boiling limit is proportional to the length of the evaporation section. When the evaporation section is repeatedly reduced, as shown by the dotted line in Figure 9, the boiling limit will Rapidly reduces to lower than other limit values at the same operating temperature, that is, the heat transfer limit is dominated by the boiling limit at this time, so the average single heat transfer of multiple heat pipes in the same channel reaches the limit. At this time, if more heat pipes are added, due to The heat flow per unit length has reached the extreme value (boiling limit/channel length). By reducing the length of the evaporation section of a single heat pipe, the increased number of heat pipes will not increase the total channel heat transfer. At this time, as shown in Figure 10 As shown, the optimal value of N is reached.

The invention also provides a heat pipe cooling reactor with radially led heat pipes. The heat pipe cooling reactor includes a core fuel 1. The core fuel 1 is composed of a plurality of core fuel elements 10 arranged in parallel; different core fuel elements 10 , the number a of the core fuel element segments 11 is not exactly the same, and the core fuel element 10 is the core fuel element described above.

In Figure 6, the heat pipe 2 can take the heat in the core fuel 1 out of the core fuel 1 and transfer it to the energy conversion device. Since the number of heat pipes 2 cooled by the system has increased by >2.5 times (in the axial heat pipe channel of a single core fuel element in Figure 3, the number of heat pipes 2 is 2; as shown in Figures 4 and 6, the number of heat pipes 2 in a single core of the present invention In the axial heat pipe channel of the fuel element, the number of heat pipes 2 is 5), the heat transmitted from a single core fuel element 10 will increase by 2.5 times, and a stronger core output power corresponds to a stronger core neutron flux. , so the reactor core has a stronger reproductive capacity; the increase in the number of heat pipes in the reactor can effectively ensure the safe operation of the reactor core.

In a preferred example, when implementing the radial heat pipe solution in a nuclear reactor using heat pipe cooling, for the core fuel 1, in order to ensure that neutrons can move smoothly throughout the core, if the core fuel 1 is All the bent heat pipes 22 are radially led out at the same axial position, which will make it difficult to arrange nuclear fuel there and may cause the nuclear reaction to stop. In order to solve the above problem, it can be considered to export the heat pipes in all the heat pipe channels in the core fuel 1 at different axial positions to ensure that when exporting at any axial position, there are always some heat pipe channels that are not in the same axial position. The heat pipe is radially led out, so that its corresponding nuclear fuel can still ensure the flow of neutrons and nuclear reactions occur; that is to say, there is no following axial position section in the heat pipe cooling reactor: the bent heat pipes 22 in this section are all in this section. The cross section is derived along the radial direction.

In a preferred example, the bent heat pipes 22 derived at the same axial position are derived using a layered superposition mode. The layered superposition mode is that, under the side view angle as shown in Figure 7, the outlets of multiple radial heat pipe lead-out channels at the same axial position are arranged in layers, and each layer is arranged with several outlets of the radial heat pipe lead-out channels. , stacked between layers. As shown in Figure 5, this schematic diagram only shows the layered superposition diagram of the heat pipes in the axial heat pipe channel corresponding to the outermost and sub-outer fuel elements in 1/6 core fuel 1, and the radial lead-out. The remaining The inner layers are also layered and drawn out in sequence.

Since it is difficult to fill the corresponding positions with nuclear fuel when the heat pipe is led out in the radial direction, it may lead to a decrease in the overall nuclear fuel in the core, affecting the core's nuclear criticality and burn-up time. Therefore, in a preferred example, in the radial lead-out area, The enrichment of fissile materials in the nearby nuclear fuel needs to be increased accordingly to ensure the criticality of the entire reactor and the long effective burn-up time.

As shown in Figure 8, the heat pipe realizes heat transfer through natural circulation in the tube. As long as the evaporation section is arranged inside the core fuel, the adiabatic section and the condensation section are arranged outside the core fuel, and the working fluid in the heat pipe in the evaporation section is , such as alkali metal lithium, sodium, potassium, etc., will evaporate when heated to form steam. Driven by expansion and natural convection, the steam moves to the low-temperature and high-density condensation section. There is a low-temperature heat absorber outside the heat pipe condensation section, and the high-temperature steam is released in the condensation section. After heating, it condenses into a liquid phase and returns to the steam section under the action of natural convection, capillary force, etc., so that the heat pipe can effectively transport heat out of the reactor core without external power. Therefore, the heat pipes in the stack operate independently during the heat transfer process and do not affect each other.

Multiple heat pipes are inserted into each axial heat pipe channel in the reactor core fuel element 10. During the operation of the reactor, the fission reaction of the core fuel releases heat to heat the evaporation section of the heat pipe in the reactor, causing the temperature of the evaporation section of the heat pipe in the reactor to rise. High, through its own natural circulation, the heat of the heat pipe in the reactor is transferred to the adiabatic section and condensation section of the heat pipe outside the reactor. The condensation section of the external heat pipe can be connected to an energy conversion device, which converts the heat in the heat pipe into electrical energy or thermal energy and transports it to the end user.

To sum up, the core operating power of the present invention is higher: since the core fuel element 10 adopts the cooling method of radially drawn heat pipes, the heat exchange capacity of the core is enhanced. Therefore, under the same core fuel structure, this method The core power is increased by > n/2 times, where n is the number of heat pipes arranged in a single axial heat pipe channel for the core fuel element 10 . The reactor core of the present invention has a stronger reproductive capacity: the internal power of the reactor is high, the neutron flux is strong, the probability of fissionable nuclides absorbing neutrons and causing a capture reaction is higher, and the rate of producing fissile nuclides is faster. The invention has higher safety: under the same core structure, the number of heat pipes that transfer core fuel heat increases. In the event of a heat pipe failure accident, the accident redundancy is larger, and there are more heat pipes to transfer heat in the reactor. Core fuel 1 is safer. The invention has a wide application range: under the same core structure, a higher power power supply can meet the needs of various solutions.

The present invention breaks through the design structure of the straight heat pipe 21 in the existing cooling core, and adopts a bent heat pipe 22 to be radially led out from the core fuel element 10, which can greatly improve the total heat transfer efficiency in a single axial heat pipe channel in the core fuel element 10 under a given single heat pipe heat transfer efficiency. All heat pipes participate in cooling during normal operation of the core. Compared with the traditional heat pipe stack design, the number of coolant channels of the core of this design remains unchanged, and the number of heat pipes and heat transfer capacity of the cooling system are>n/2 times that of the existing heat pipe stack design, where n is the number of heat pipes arranged in a single axial heat pipe channel for the core fuel element 10.

The present invention leads part of the heat pipes 2 out of the fuel core 1, so that the axial heat pipe channel of the core fuel element 10, which originally could be arranged with one heat pipe or two heat pipes, can be passed through. By leading the heat pipes radially from between the segments, More than 2 heat pipes can be arranged, so that multiple (>2) heat pipes can be arranged according to power requirements, effectively improving the heat exchange capacity of the overall heat pipe, thereby increasing the effective power of the heat pipe cooling stack.

In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", The orientations or positional relationships indicated by "bottom", "inner", "outer", etc. are based on the orientations or positional relationships shown in the drawings. They are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying the device referred to. Or elements must have a specific orientation, be constructed and operate in a specific orientation and therefore are not to be construed as limitations on the application.

Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above. Those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. The embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily without conflict.

Claims (9)

1. A core fuel element, characterized in that the core fuel element (10) is for constituting a core fuel (1), said core fuel (1) being for constituting a heat pipe cooled reactor;

the core fuel element (10) is divided into a core fuel element segments (11) along the axis; a is greater than 2;

one or more axial heat pipe channels are arranged in each reactor core fuel element segment (11); axial heat pipe channels in adjacent reactor core fuel element segments (11) are in one-to-one correspondence, and the axial heat pipe channels corresponding to each other are communicated;

in addition to the core fuel element segments (11) positioned at the head end and the tail end, each core fuel element segment (11) is also provided with radial heat pipe extraction channels along the radial direction, and the number of the core fuel element segments (11) provided with the radial heat pipe extraction channels is a-2; the axial heat pipe channels in the reactor core fuel element segment (11) are in one-to-one correspondence with the radial heat pipe leading-out channels in the reactor core fuel element segment (11), and the axial heat pipe channels corresponding to each other are communicated with the radial heat pipe leading-out channels;

the axial heat pipe channel and the radial heat pipe leading-out channel both accommodate the heat pipe (2);

each heat pipe (2) has one end located within the axial heat pipe passage and the other end located outside the core fuel element (10).

2. The core fuel element according to claim 1, characterized in that each core fuel element segment (11) is provided with an axial heat pipe channel therein; the axial heat pipe channels in the adjacent reactor core fuel element segments (11) are sequentially communicated to form an axial heat pipe channel in the reactor core fuel element (10);

one heat pipe (2) is arranged in each core fuel element segment (11).

3. The core fuel element of claim 2, characterized in that the heat pipe (2) comprises a straight heat pipe (21) and a bent heat pipe (22);

straight heat pipes (21) are arranged in the axial heat pipe channels in the core fuel element segments (11) at the two ends; one end of the straight heat pipe (21) is arranged in the axial heat pipe channel of the reactor core fuel element segment (11), and the other end extends out of the axial heat pipe channel;

bending heat pipes (22) are arranged in the axial heat pipe channels in the fuel element segments (11) of the rest reactor core segments; one end of the bent heat pipe (22) is positioned in the axial heat pipe channel, and the other end extends towards the radial heat pipe leading-out channel and extends to the outside of the radial heat pipe leading-out channel.

4. The core fuel element according to claim 1, characterized in that the number of core fuel element segments (11) is 5, being a first core fuel element segment (111), a second core fuel element segment (112), a third core fuel element segment (113), a fourth core fuel element segment (114) and a fifth core fuel element segment (115), respectively; the 5 reactor core fuel element segments (11) are sequentially arranged;

a straight heat pipe (21) is arranged in each of the first core fuel element segment (111) and the fifth core fuel element segment (115);

one bent heat pipe (22) is arranged in each of the second core fuel element segment (112), the third core fuel element segment (113) and the fourth core fuel element segment (114).

5. The core fuel element of claim 1, wherein the number of heat pipes (2) in one core fuel element (10) is N, where N is optimal when the average heat pipe heat exchange efficiency in the channel is equal to the boiling limit heat exchange efficiency at a given heat pipe operating temperature, and where the heat pipe channel heat exchange efficiency of the core fuel element is highest.

6. A heat pipe cooled reactor with radially directed heat pipes, comprising a core fuel (1), the core fuel (1) being formed by a plurality of core fuel elements (10) arranged in parallel; the core fuel element (10) is the core fuel element of any one of claims 1-5.

7. A heat pipe cooled reactor with radially directed heat pipes as claimed in claim 6,

the following axial position cross section is not present in the heat pipe cooled reactor: the folded heat pipes (22) in the cross section are all led out radially at the cross section.

8. The heat pipe cooled reactor with radially directed heat pipes as recited in claim 6 wherein the folded heat pipes (22) directed at the same axial location are directed in a layered stacked pattern.

9. The heat pipe cooled reactor with radially directed heat pipes of claim 6 wherein the layered stack mode is: in the side view, the outlets of a plurality of radial heat pipe leading-out channels at the same axial position are arranged in layers, each layer is provided with the outlets of a plurality of radial heat pipe leading-out channels, and the layers are stacked.