CN110634579A

CN110634579A - Fuel and strong neutron absorbing material integrated compact reactor core structure

Info

Publication number: CN110634579A
Application number: CN201911023037.5A
Authority: CN
Inventors: 曾勤; 史莹; 李志峰; 杨逸; 杨锦琛; 李承昊
Original assignee: South China University of Technology SCUT
Current assignee: South China University of Technology SCUT
Priority date: 2019-10-25
Filing date: 2019-10-25
Publication date: 2019-12-31

Abstract

The invention discloses a compact reactor core structure integrating fuel and a strong neutron absorbing material, which comprises a core active area with a core fuel element group, a reflecting layer surrounding the periphery of the core active area and a control drum arranged in the reflecting layer, wherein the control drum can rotate around a mounting shaft, a first area and a second area are arranged in the control drum, the first area is provided with a strong neutron absorber, and the second area is provided with a drum fuel element group. The control drum is internally provided with a drum fuel element group and a strong neutron absorber at the same time, the control drum can be rotated, and the relative position of the drum fuel element group and the reactor core active region is adjusted to meet the requirement of reactor power regulation; the operational life of the reactor core may be increased. The reactor has maximum reactivity when the drum fuel element group portions in the control drum all face the active core region, and has maximum shutdown depth when the strong neutron absorbers in the control drum all face the active core region.

Description

Fuel and strong neutron absorbing material integrated compact reactor core structure

Technical Field

The invention relates to the field of nuclear reactor engineering, in particular to a compact reactor core structure integrating fuel and a strong neutron absorbing material.

Background

With the continuous development and maturity of human exploration technologies in the fields of space, deep sea, ocean and the like and the expansion of exploration application requirements, human hopes to establish space bases, deep sea bases and the like for scientific research. For example, in the future, building a space base on the surface of other human stars (such as moon, Mars, etc.), building a deep sea base on the deep sea bottom, and building a scientific research base on an island far away from the continent will have significant scientific, military and political values. The construction of these bases faces complex and severe environments, and the stable supply and management of energy is an important guarantee for the bases to operate normally. Solar power sources cannot be applied to deep sea, and have inherent defects of the solar power sources in the fields of space and ocean, such as incapability of overcoming day-night changes. Chemical energy power is limited by fuel reserves and supplies and cannot run at high power for a long time. The nuclear reactor power supply is not influenced by the environment, has high power, long service life, safety and reliability and strong energy supply sustainability, and is considered as an ideal and reliable energy supply scheme in the base detection tasks of space bases, deep sea bases, ocean oceans and the like.

Since nuclear reactors have many irreplaceable advantages in site construction and other detection tasks, countries in the united states, russia, japan, france, and the like have intensively studied nuclear reactors in terms of miniaturization, weight reduction, noise reduction, and the like, and dozens of nuclear reactor solutions have been proposed, including gas cooling, liquid metal cooling, heat pipe cooling, and the like. In consideration of the complexity of the base environment, the nuclear reactor with the passive cooling technology is one of the most main schemes, and the heat pipe cooling technology is the passive cooling technology with the advantages of high thermal conductivity, high transient feedback performance, high reliability, low maintenance requirement and the like, so the current base nuclear reactor is mostly designed by adopting heat pipe cooling.

In the core design of the conventional compact heat pipe nuclear reactor, as shown in fig. 7 to 10, a main control mode is that a strong neutron absorber 13 or a reflecting material matrix 14 is arranged at the periphery of a core active area 1, and the purpose of controlling the reactor is achieved by controlling the number of neutrons absorbed by the strong neutron absorber 13 or reflected by the reflecting material matrix 14. Fig. 7 shows a control drum control method, in which the strong neutron absorber 13 and the reflective material substrate 14 are embedded in the control drum body, and the relative positions of the strong neutron absorber 13, the reflective material substrate 14 and the core active region 1 are changed by rotation, so as to achieve the purpose of controlling reactivity, and the control drum is arranged in the reflective layer 2 of the core. The control drums are arranged in a manner that they are not easily deformed and dropped in the event of an accident, but increase the size and mass of the outer reflector 2, thereby increasing the core weight.

In fig. 8 and 9, the reactivity of the core is controlled by controlling the neutron leakage rate of the core active region 1 by arranging the reflecting layer 2 outside the core active region 1 and controlling the reflecting layer 2. In fig. 8, the control is performed by sliding the reflective layer 2 up and down, and in fig. 9, the reflective layer 2 is controlled by an open-close type manner. Because the reflecting layer 2 is arranged on the outer side, the irradiation damage of materials is small, the working temperature is low, but under the accident condition, the possibility of deformation and falling of the reflecting layer 2 is high, and meanwhile, the disturbance on the axial power density distribution is large in the sliding or opening and closing process of the reflecting layer 2.

In fig. 10, the reflecting layer 2 is disposed outside the core active region 1, a layer of strong neutron absorber 13 is disposed between the reflecting layer 2 and the core active region 1, and the relative positions of the absorber and the reflector and the core active region 1 are controlled by sliding the strong neutron absorber 13 up and down, thereby achieving the purpose of controlling the reactivity. In this way, similar to the control of the reflective layer 2 shown in fig. 8, changing the reflective layer 2 into a slipping strong neutron absorber 13, the absorber is more likely to deform and fall off in the event of an accident, while the disturbance to the axial power density distribution during slipping is greater.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art and to providing a compact reactor core structure with integrated fuel and strong neutron absorbing material.

According to an embodiment of a first aspect of the present invention, a compact reactor core structure with fuel and strong neutron absorbing material integrated is provided, which comprises a core active area with a core fuel element group, a reflecting layer surrounding the periphery of the core active area, and a control drum arranged in the reflecting layer, wherein the control drum can rotate around a mounting shaft, a first area and a second area are arranged in the control drum, the first area is provided with the strong neutron absorbing body, and the second area is provided with the drum fuel element group.

The compact reactor core structure at least has the following beneficial effects: the control drum is internally provided with a drum fuel element group and a strong neutron absorber at the same time, the control drum can be rotated, and the relative position of the drum fuel element group and the reactor core active region is adjusted to meet the requirement of reactor power regulation; the operational life of the reactor core may be increased. The reactor has maximum reactivity when the drum fuel element group portions in the control drum all face the active core region, and has maximum shutdown depth when the strong neutron absorbers in the control drum all face the active core region. The invention can simultaneously control the reactor power and the reactor operation period by adjusting and controlling the rotation angle of the rotary drum. The invention has high structure safety, good reliability and compact layout, can improve the core life of the reactor, and is particularly suitable for deep sea, ocean or space nuclear reactors and other small nuclear reactors.

According to the compact reactor core structure of the embodiment of the first aspect of the invention, the core active area is a regular polygon star, and the control drums are distributed between two adjacent corners of the regular polygon star. The core active regions are arranged into regular multi-angle stars, and the control rotary drums are uniformly distributed between two adjacent angles of the regular multi-angle stars, so that the stability of the reactor core during operation is provided.

According to the compact reactor core structure of the first aspect of the present invention, a recess is formed between two adjacent corners of the regular polygon, and part or all of the control drum is located in the recess.

According to the compact reactor core structure of the embodiment of the first aspect of the invention, the core fuel element group comprises a honeycomb-shaped fuel element base and a plurality of fuel elements, a cooling area is formed between two adjacent fuel elements, and the fuel elements comprise a cavity, a fuel cladding, fuel pellets positioned between the cavity and the fuel cladding, a locking device used for locking the fuel element base and a fission gas cavity arranged at one end or two ends of the fuel elements. The fuel elements in the reactor core fuel element group are arranged on the honeycomb fuel element base, the structure is compact and stable, and the reactor core fuel element group is arranged in the coolant, so that the reactor core fuel element group has a good heat exchange effect.

According to the compact reactor core structure disclosed by the embodiment of the first aspect of the invention, a gap of 0.1-0.3 mm is left between the fuel pellets and the fuel cladding.

According to the compact reactor core structure of the embodiment of the first aspect of the invention, the fuel element base has a polygonal shape or a circular shape.

According to the compact reactor core structure of the embodiment of the first aspect of the invention, the drum fuel element group comprises a plurality of fuel elements, and the fuel elements are arranged in the reflecting material matrix of the control drum.

According to the compact reactor core structure provided by the embodiment of the first aspect of the invention, the strong neutron absorbers are in a sheet shape or a block shape, and a gap of 0.3-0.5 mm exists between two adjacent strong neutron absorbers.

According to the compact reactor core structure of the embodiment of the first aspect of the invention, the first area is semicircular, the second area is semicircular, and the first area and the second area are in contact through a plane or a cambered surface.

Compared with the prior art, the invention has the beneficial effects that:

(1) the control drum is internally provided with a drum fuel element group and a strong neutron absorbing material at the same time, fuel elements in the drum fuel element group are arranged in a reflecting material substrate, and the relative positions of the fuel elements in the drum fuel element group and the core active region are adjusted by rotating the control drum, so that the reactivity and the power of the reactor are adjusted, and the effects of starting, stopping, adjusting the power and the like are achieved.

(2) The fuel elements in the plurality of core fuel element groups are mounted on a honeycomb fuel element base to constitute a core active region of the reactor. The honeycomb base and the rotary drum fuel element group in the control rotary drum improve the compactness of the arrangement of the reactor core fuel, thereby improving the filling rate of the nuclear fuel, reducing the volume of the reactor core and reducing the critical quality.

Drawings

In order to more clearly illustrate the technical solution in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly described below. It is clear that the described figures are only some embodiments of the invention, not all embodiments, and that a person skilled in the art can also derive other designs and figures from them without inventive effort.

FIG. 1 is a first radial cross-sectional structural schematic of an embodiment of the present invention;

FIG. 2 is a radial cross-sectional view of the embodiment of the present invention;

FIG. 3 is an axial view of the fuel elements in the core fuel element group in accordance with an embodiment of the present invention;

FIG. 4 is a radial view of the fuel elements in the core fuel element group in accordance with an embodiment of the present invention;

FIG. 5 is a schematic diagram of the assembly of fuel elements in a core fuel element group on a fuel element base according to an embodiment of the present invention;

FIG. 6 is a radial schematic view of a control drum in an embodiment of the present invention;

FIG. 7 is a first schematic diagram of a core of a prior art compact heat pipe nuclear reactor;

FIG. 8 is a second schematic structural diagram of a core of a conventional compact heat pipe nuclear reactor;

FIG. 9 is a schematic illustration of a core of a prior art compact heat pipe nuclear reactor;

fig. 10 is a fourth structural schematic diagram of a core of a prior art compact heat pipe nuclear reactor.

Detailed Description

Reference will now be made in detail to the present preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

As shown in fig. 1 to 6, the compact reactor core structure integrating fuel and strong neutron absorbing material comprises a core active area 1 having a core fuel element group 17, a reflecting layer 2 surrounding the periphery of the core active area 1, and a control drum 3 arranged in the reflecting layer 2, wherein the control drum 3 can rotate around a mounting shaft, the control drum 3 has a first region 16 and a second region 15, the first region 16 is provided with a strong neutron absorber 13, and the second region 15 is provided with a drum fuel element group 18.

Preferably, the control drum 3 can be rotated freely through 360 ° around the mounting shaft.

Preferably, the reflecting layer 2 is made of a material with strong scattering and weak absorption of neutrons.

The control drum 3 is internally provided with a drum fuel element group 18 and a strong neutron absorber 13 at the same time, so that the control drum 3 can be rotated to adjust the relative positions of the drum fuel element group 18 and the core active region 1, and the requirement of reactor power regulation is met; the operational life of the reactor core may be increased. The reactor has the greatest reactivity when the drum fuel element groups 18 in the control drum 3 are all facing the core active areas 1, and the reactor has the greatest shutdown depth when the strong neutron absorbers 13 in the control drum 3 are all facing the core active areas 1. The invention can simultaneously control the reactor power and the reactor operation period by adjusting and controlling the rotation angle of the rotary drum 3. The invention has high structure safety, good reliability and compact layout, can improve the core life of the reactor, and is particularly suitable for deep sea, ocean or space nuclear reactors and other small nuclear reactors.

The core active region 1 is a regular polygonal star, and the control rotary drums 3 are distributed between two adjacent corners in the regular polygonal star. The core active regions 1 are arranged into regular multi-angular stars, and the control rotary drums 3 are uniformly distributed between two adjacent angles of the regular multi-angular stars, so that the stability of the reactor core during operation is provided. Preferably, the core active area 1 is a regular quadrangle star, a regular hexagon star, a regular octagon star, a regular decagon star or a regular dodecagon star.

A concave part 20 is formed between two adjacent corners in the regular polygon, and part or all of the control drum 3 is positioned in the concave part 20. The concave surface of the concave portion 20 has a circular arc-shaped cross section. The concave surface of the concave portion 20 subtends a circular angle of 60 DEG to 180 deg. The concave part 20 is smoothly connected with the corner of the regular polygon through a cambered surface.

The core fuel element group 17 comprises a honeycomb-shaped fuel element base 12 and a plurality of fuel elements 10, a cooling area is formed between two adjacent fuel elements 10, and each fuel element 10 comprises a cavity 4, a fuel cladding 6, a fuel pellet 5 positioned between the cavity 4 and the fuel cladding 6, a locking device 7 used for locking the fuel element base and a fission gas cavity 8 arranged at one end or two ends of each fuel element 10. The fuel element base 12 is provided with a coolant flow channel 11, the cavity 4 is communicated with the coolant flow channel 11, the fuel elements 10 in the fuel element group 17 are arranged on the honeycomb-shaped fuel element base 12, the structure is compact and stable, the fuel element group 17 is placed in the coolant, the coolant flows through the cooling area, the cavity 4 and the coolant flow channel 11 to take away heat generated when the fuel element group 17 works, and the heat exchange effect is good.

Preferably, the fuel pellets 5 are small cylinders with a central opening, and a plurality of fuel pellets 5 are contained in one fuel element 10, with a plurality of fuel pellets 5 being arranged in the middle of the fuel element 10.

And a gap of 0.1-0.3 mm is reserved between the fuel pellet 5 and the fuel cladding 6.

The fuel element base 12 has a polygonal or circular shape. When the fuel element base 12 has a polygonal shape, the corners of the fuel element base 12 face the corners of the core active region 1.

The drum fuel element set 18 comprises a plurality of fuel elements disposed within the reflective material matrix 14 of the control drum 3. The reflecting material base 14 is provided with a coolant flow path 11 therein. The cavity 4 is communicated with the coolant flow channel 11, the rotary drum fuel element group 18 is placed in the coolant, the coolant flows through the cavity 4 and the coolant flow channel 11 to take away heat generated when the reactor core fuel element group 17 works, and the heat exchange effect is good. The fuel elements in the rotary drum fuel element set 18 comprise a cavity, a fuel cladding, fuel pellets located between the cavity and the fuel cladding, locking means for locking to a reflective material matrix, and a fission gas cavity disposed at one or both ends of the fuel element.

The strong neutron absorbers 13 are in a sheet shape or a block shape, and a gap of 0.3-0.5 mm exists between every two adjacent strong neutron absorbers 13.

The first region 16 is semicircular, the second region 15 is semicircular, and the first region 16 and the second region 15 are in contact through a plane or an arc surface 19.

Taking the core design of a nuclear reactor applied to deep sea or space as an example, the design life of the nuclear fuel element and the control rotary drum 3 is consistent with the core life, and the nuclear fuel element and the control rotary drum do not need to be replaced in the core life. As shown in fig. 1 to 6, the core active region 1 is a regular hexagon star, and the number of the control drums 3 is 6.

In fig. 1, the reactor has the maximum reactivity when the drum fuel element groups 18 of the 6 control drums 3 are partially facing the core active region 1.

As shown in fig. 2, of the 6

control drums

3, 3 control drums 3 have fuel elements facing the core

active area

1, and 3 control drums 3 have strong neutron absorbers 13 facing the core active area 1. The control drums 3 of the fuel elements facing the core active zone 1 and the control drums 3 of the strong neutron absorbers 13 facing the core active zone 1 are staggered.

As shown in fig. 1 and 2, due to the arrangement of both fuel elements and strong neutron absorbing material in the control drum 3, the control drum 3 can be rotated to adjust the relative positions of the fuel elements and the core active area 1 to meet the requirements of reactor power regulation, and the operating life of the reactor core can be increased.

The reactor has the greatest depth of shut-down when the strong neutron absorbers 13 in the 6 control drums 3 all face the core active zone 1. By adjusting the rotation angle of the control rotary drum 3, the reactor power and the reactor operation period can be controlled simultaneously. The structure has high safety, good reliability and compact layout, and can improve the life time of the reactor core.

As shown in fig. 3, 4 and 5, the fuel elements in the core fuel element group 17 are arranged on the honeycomb-shaped fuel element base 12, so that the compactness of the core fuel arrangement is improved, the nuclear fuel filling rate is improved, the core volume is reduced, and the critical mass is reduced.

While the preferred embodiments of the present invention have been illustrated and described, it will be understood by those skilled in the art that the present invention is not limited to the details of the embodiments shown and described, but is capable of numerous equivalents and substitutions without departing from the spirit of the invention as set forth in the claims appended hereto.

Claims

1. The compact reactor core structure of fuel and strong neutron absorbing material integration, its characterized in that: the control drum can rotate around a mounting shaft, a first area and a second area are arranged in the control drum, the first area is provided with a strong neutron absorber, and the second area is provided with a drum fuel element group.

2. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 1, wherein: the core active area is a regular multi-angular star, and the control rotary drums are distributed between two adjacent angles in the regular multi-angular star.

3. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 2, wherein: a concave part is formed between two adjacent corners in the regular polygon, and part or all of the control rotary drum is positioned in the concave part.

4. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 1, wherein: the core fuel element group comprises a honeycomb-shaped fuel element base and a plurality of fuel elements, a cooling area is formed between every two adjacent fuel elements, and each fuel element comprises a cavity, a fuel cladding, fuel pellets positioned between the cavity and the fuel cladding, a locking device used for locking the fuel element base and a fission gas cavity arranged at one end or two ends of the fuel element.

5. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 4, wherein: and a gap of 0.1-0.3 mm is reserved between the fuel pellet and the fuel cladding.

6. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 4, wherein: the fuel element base is polygonal or circular.

7. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 1, wherein: the drum fuel element set includes a plurality of fuel elements disposed within a reflective material matrix of the control drum.

8. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 1, wherein: the strong neutron absorbers are in a sheet shape or a block shape, and a gap of 0.3-0.5 mm exists between every two adjacent strong neutron absorbers.

9. The fuel and strong neutron absorbing material integrated compact reactor core structure of claim 1, wherein: the first area is semicircular, the second area is semicircular, and the first area and the second area are in contact through a plane or an arc surface.