CN114388151A

CN114388151A - Pebble bed reactor structure

Info

Publication number: CN114388151A
Application number: CN202111546921.4A
Authority: CN
Inventors: 孟剑; 汪景新; 周勤; 罗勇; 罗宝军
Original assignee: Huaneng Group Technology Innovation Center Co Ltd; Huaneng Shandong Shidaobay Nuclear Power Co Ltd; Huaneng Nuclear Energy Technology Research Institute Co Ltd
Current assignee: Huaneng Group Technology Innovation Center Co Ltd; Huaneng Shandong Shidaobay Nuclear Power Co Ltd; Huaneng Nuclear Energy Technology Research Institute Co Ltd
Priority date: 2021-12-16
Filing date: 2021-12-16
Publication date: 2022-04-22

Abstract

The invention provides a pebble bed reactor structure.A control rod pore passage and an absorption sphere pore passage are arranged in a middle reflecting layer and a side reflecting layer of a reactor core, wherein the reactor core is in an annular cylinder structure, the middle reflecting layer is positioned at the center of the reactor core, and the side reflecting layer is positioned at the outer side of the reactor core. Through arranging control rod and absorption ball in the middle reflector and the side reflector of reactor core, can improve neutron absorption value, the flat reactor core of exhibition distributes, improves reactor core power density, reduces the quantity of control rod and absorption ball, is favorable to the trompil of reactor pressure vessel top cap to be arranged.

Description

Pebble bed reactor structure

Technical Field

The invention relates to the technical field of reactor engineering, in particular to a pebble bed reactor structure.

Background

The ball bed type high temperature gas cooled reactor has inherent safety and high coolant outlet temperature, and is an advanced reactor type with fourth generation nuclear power characteristics. The ball bed type high temperature gas cooled reactor adopts full ceramic coated granular spherical fuel element, helium as coolant and graphite as moderator. The reactor consists of an active zone (spherical fuel element), a control rod (reactivity control system), an absorption sphere (shutdown system), a reflecting layer (ceramic reactor internals) and a metal reactor internals, and is contained in a reactor pressure vessel. In the operation process, the spherical fuel elements continuously enter the reactor core from the top of the reactor, and meanwhile, a plurality of spent fuel balls are discharged from the bottom of the reactor, so that the purpose of refueling without stopping the reactor is realized.

In the traditional pebble bed type high-temperature gas cooled reactor, a control rod and an absorption sphere shutdown system are arranged in a reflecting layer at the periphery of a reactor core. The defects that the arrangement of the control rods and the absorption spheres is far away from the middle part of the reactor core, the neutron absorption value is low, the required quantity is large, and the power flattening of the reactor core is not facilitated; meanwhile, a large number of dense holes need to be arranged on the top cover of the reactor pressure vessel, and the processing is difficult.

The current arrangement is that the side reflective layer is arranged with 24 sets of control rods and 6 sets of absorption balls as the control means of the 250MWt power reactor.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art.

The invention aims to provide a pebble bed reactor structure, which can improve neutron absorption value, flatten reactor core distribution, improve reactor core power density, reduce the number of control rods and absorption spheres and facilitate the arrangement of holes on a top cover of a reactor pressure vessel by arranging the control rods and the absorption spheres in a middle reflecting layer and a side reflecting layer of a reactor core.

The embodiment of the application provides a pebble bed reactor structure, arranges control rod pore and absorption sphere pore in the middle reflector and the side reflector of the reactor core, wherein the reactor core is in a circular cylinder structure, the middle reflector is located at the center of the reactor core, and the side reflector is located outside the reactor core.

In some embodiments, the intermediate reflective layer is a cylindrical structure.

In some embodiments, the side reflective layer is in the form of an annular cylinder structure.

In some embodiments, the intermediate reflective layer has a plurality of control rod and/or absorber ball ports uniformly disposed near the edge, and the plurality of control rod and/or absorber ball ports are annularly disposed.

In some embodiments, the side reflective layer is uniformly arranged with a plurality of control rod bores and/or absorption ball bores near the edge of the inner ring, and the plurality of control rod bores and/or absorption ball bores are arranged in a ring shape.

In some embodiments, the total number of control rod bores and absorber ball bores in the side reflector layer is greater than the total number of control rod bores and absorber ball bores in the middle reflector layer.

In some embodiments, the number of the absorption ball holes is 4-8, and the number of the control rod holes is 14-24.

In some embodiments, the control rod port and the absorption ball port are both reserved for stacking of graphite bricks in the reflecting layer.

In some embodiments, the control rod orifice is circular in cross-section and the absorber ball orifice is circular or oblong in cross-section.

In some embodiments, a top reflecting layer is arranged above the core, and a bottom reflecting layer is arranged below the core.

The invention has the beneficial effects that: the reactor core can improve neutron absorption value, flatten reactor core distribution, improve reactor core power density, reduce the quantity of control rods and absorption balls, and be favorable to the trompil of reactor pressure vessel top cap to be arranged.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent from and readily appreciated by reference to the following description of the embodiments taken in conjunction with the accompanying drawings,

wherein:

FIG. 1 is a schematic view of a top view of a pebble bed reactor structure according to an embodiment of the present application;

FIG. 2 is a sectional elevation view of a pebble bed reactor structure in an embodiment of the present application;

FIG. 3 is a schematic diagram of the internal structure of a pebble bed reactor structure according to an embodiment of the present application;

reference numerals:

1-a reactor pressure vessel; 2-metal internals; 3-side reflective layer; 4-a pore channel; 5, a reactor core; 6-intermediate reflective layer; 7-absorbent sphere pore canals; 8-control rods; 9-a top reflective layer; 10-bottom reflective layer; 11-an absorbent ball discharge mechanism; 12-a feed pipe; 13-top cover.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

A pebble bed reactor structure according to an embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in fig. 1 to 3, the present invention provides a pebble bed reactor structure, which includes a reactor pressure vessel 1, a metal internals 2, a middle reflector 6, a side reflector 3, a top reflector 9, a bottom reflector 10, a core 5, control rods 8, a feed pipe 12 and an absorption sphere discharge mechanism 11, wherein the metal internals 2 are disposed inside the reactor pressure vessel 1, the metal internals 2 are composed of a core shell, an upper support plate, a lower support plate and the like, and only a cylindrical portion of the core shell is shown in fig. 2. The outlet of the feeding pipe 12 is positioned above the reactor core 5, the absorption ball discharging mechanism 11 is connected with the bottom end of the absorption ball hole 7, the absorption balls are discharged from the bottom of the reactor for recovery, and each group of absorption balls uses one ball storage tank.

Reactivity and shutdown of the core 5 are controlled by the control rods 8 and the absorption spheres, respectively. The control rods perform normal reactivity control, compensation and regulation, and thermal shutdown under various working conditions. The absorption ball plays the roles of standby shutdown and cold shutdown maintenance, and the safety of the reactor is ensured.

The middle reflector 6 is located at the center of the core 5, the side reflectors 3 are located outside the core 5, the top reflector 9 is located above the core 5, and the bottom reflector 10 is located below the core 5. The reactor core 5 is in an annular cylinder structure, spherical fuel elements are filled in the reactor core 5, the middle reflecting layer 6 is in a cylinder structure, and the side reflecting layers 3 are in an annular cylinder structure. Control rod ports and absorption sphere ports 7 are arranged in the middle reflector 6 and the side reflectors 3 of the core 5. Each reflecting layer is formed by stacking graphite bricks.

The middle reflecting layer 6 is uniformly provided with a plurality of pore channels 4 near the edge, the pore channels 4 can be all control rod pore channels or all absorption ball pore channels 7, or both the control rod pore channels and the absorption ball pore channels 7, and the pore channels 4 are annularly arranged on the middle reflecting layer 6.

The side reflecting layer 3 is evenly provided with a plurality of pore channels 4 near the edge of the inner ring, the pore channels 4 can be all control rod pore channels or all absorption ball pore channels 7, or both the control rod pore channels and the absorption ball pore channels 7, and the pore channels 4 are annularly arranged on the side reflecting layer 3.

The control rod pore passage and the absorption ball pore passage 7 are both pore passages 4 reserved when graphite bricks in the reflecting layer are piled up.

The total number of control rod ports and absorption ball ports 7 in the side reflective layer 3 is greater than the total number of control rod ports and absorption ball ports 7 in the middle reflective layer 6.

In some specific embodiments, the number of the control rods 8 and the absorption balls arranged in the side reflective layers 3 and the middle reflective layer 6 is determined according to the neutron absorption value of the control rods 8 and the absorption balls, the number of the absorption balls ranges from 4 groups to 8 groups, and the number of the control rods 8 ranges from 14 groups to 24 groups.

In some embodiments, the absorption ball port 7 and the control rod port are sized differently. The cross section of the control rod pore passage is circular, and the cross section of the absorption ball pore passage 7 is circular (a pore passage used by one group of absorption balls) or oblong (a pore passage shared by two adjacent groups of absorption balls).

In some specific embodiments, only a part of the arranged ducts 4 may be used, or all of the ducts may be used, according to actual needs.

The invention is further described below by means of specific examples.

Example 1

8 groups of control rods are uniformly distributed on the middle reflecting layer 6 along the circumference, 16 groups of

control rods

8 and 8 groups of absorption balls are arranged on the side reflecting layer 3 along the circumference in a staggered mode, and the highest thermal power of the reactor can reach 400 MWt.

Example 2

The middle reflecting layer 6 is circumferentially and alternately provided with 4 groups of absorption balls and 4 groups of control rods 8, the side reflecting layer 3 is circumferentially and uniformly provided with 12 groups of control rods 8, the thermal power of the reactor can reach 300MWt at most, and the number of holes on the top cover 13 of the reactor pressure vessel 1 can be reduced.

Example 3

6 groups of absorption balls are uniformly distributed on the middle reflecting layer 6 along the circumference, 16 groups of control rods 8 are uniformly distributed on the side reflecting layer 3 along the circumference, the thermal power of the reactor can reach 250MWt at most, and the number of holes on the top cover 13 of the reactor pressure vessel 1 can be reduced.

Example 4

8 groups of absorption balls are uniformly distributed on the middle reflecting layer 6 along the circumference, 24 groups of control rods 8 are uniformly distributed on the side reflecting layer 3 along the circumference, and the highest thermal power of the reactor can reach 400 MWt.

Example 5

The middle reflecting layer 6 is uniformly distributed with 8 groups of control rods 8 along the circumference, the side reflecting layer 3 is arranged with 8 groups of

control rods

8 and 4 groups of absorption balls along the circumference in a staggered way, the thermal power of the reactor can reach 300MWt at most, and the number of holes on the top cover 13 of the reactor pressure vessel 1 can be reduced.

Example 6

6 groups of control rods 8 are uniformly distributed on the middle reflecting layer 6 along the circumference, 8 groups of

control rods

8 and 4 groups of absorption balls are arranged on the side reflecting layer 3 along the circumference in a staggered mode, the maximum reactor thermal power can reach 250MWt, and the number of holes formed in the top cover 13 of the reactor pressure vessel 1 can be reduced.

Since each control rod 8 requires a control rod drive mechanism to provide a source of power, an opening in the head 13 of the reactor pressure vessel 1 is required to be provided. The provision of the control rods 8 in the intermediate reflector 6 facilitates core power flattening and therefore reduces the overall number of control rods 8 and hence the number of openings in the head 13 of the reactor pressure vessel 1. The number of the open holes of the top cover 13 of the reactor pressure vessel 1 as in example 2 is 20 in total, and the arrangement of the prior art is such that 24 sets of control rods and 6 sets of absorption balls are arranged for the side reflection layer, and the total number is 30, compared with example 2, the number of the open holes is reduced, and the reactor power is improved.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; may be mechanically coupled, may be electrically coupled or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the present disclosure, the terms "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" and the like mean that a specific feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present disclosure. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.

Claims

1. A pebble bed reactor structure characterized in that control rod ports and absorption sphere ports are arranged in a middle reflector and a side reflector of a core, wherein the core is in a circular cylindrical structure, the middle reflector is positioned at the center of the core, and the side reflector is positioned at the outer side of the core.

2. The pebble bed reactor structure of claim 1, wherein the intermediate reflective layer is a cylindrical structure.

3. The pebble bed reactor structure of claim 1, wherein the side reflector layer is in the form of an annular cylinder structure.

4. The pebble bed reactor structure of claim 2, wherein the intermediate reflector layer has a plurality of control rod and/or absorption ball ports uniformly disposed near the edge, the plurality of control rod and/or absorption ball ports being annularly disposed.

5. The pebble bed reactor structure of claim 3, wherein the side reflector layer has a plurality of control rod and/or absorption sphere openings uniformly disposed proximate an edge of the inner ring, the plurality of control rod and/or absorption sphere openings being annularly disposed.

6. The pebble bed reactor structure of claim 1, wherein the total number of control rod openings and absorber ball openings in the side reflector layer is greater than the total number of control rod openings and absorber ball openings in the middle reflector layer.

7. The pebble bed reactor structure of claim 1, wherein the number of the absorber sphere openings used is 4 to 8 and the number of the control rod openings used is 14 to 24.

8. The pebble bed reactor structure of any one of claims 1 to 7, wherein the control rod port and the absorber sphere ports are each ports reserved for the stacking of graphite bricks in the reflector layer.

9. The pebble bed reactor structure of claim 1, wherein the control rod openings are circular in cross-section and the absorber ball openings are circular or oblong in cross-section.

10. The pebble bed reactor structure of claim 1 wherein a top reflector is provided above the core and a bottom reflector is provided below the core.