阅读说明：本技术 一种反应堆容器的下腔室结构及反应堆容器 (Lower cavity structure of reactor container and reactor container ) 是由 田�健 王允 张金红 周翀 傅瑶 邹杨 于 2020-06-23 设计创作，主要内容包括：本发明公开了一种反应堆容器的下腔室结构及反应堆容器,其包括堆芯支撑底板、反应堆容器下封头和反应堆下腔室入口；其包括的流量分配板圆板与堆芯支撑底板平行固接；流量分配板圆板的径向宽度小于堆芯支撑底板的径向宽度；流量分配板圆板的径向宽度大于等于堆芯支撑底板上分布有孔的圆形区域的直径、且不与反应堆容器下封头内部接触；反应堆下腔室入口设于流量分配板圆板下方区域的反应堆容器下封头上；其还包括流量分配板上开孔圆板,流量分配板上开孔圆板设有通孔。本发明的下腔室结构有效改善了下腔室的流场特性,避免了下腔室中旋涡的出现,结合堆芯下支撑板对流体进行流量分配,使进入堆芯的流体流量分布达到反应堆设计目标。(The invention discloses a lower cavity structure of a reactor container and the reactor container, which comprises a reactor core supporting bottom plate, a reactor container lower end enclosure and a reactor lower cavity inlet; the circular plate of the flow distribution plate is fixedly connected with the reactor core supporting bottom plate in parallel; the radial width of the circular plate of the flow distribution plate is less than that of the reactor core support bottom plate; the radial width of the circular plate of the flow distribution plate is more than or equal to the diameter of a circular area with holes distributed on the reactor core support bottom plate and is not contacted with the inside of the lower end enclosure of the reactor vessel; the inlet of the reactor lower cavity chamber is arranged on the reactor vessel lower end enclosure in the area below the circular plate of the flow distribution plate; the flow distribution plate is provided with an opening circular plate, and the opening circular plate is provided with a through hole. The lower cavity structure effectively improves the flow field characteristic of the lower cavity, avoids the vortex in the lower cavity, and distributes the flow of the fluid by combining the lower support plate of the reactor core, so that the flow distribution of the fluid entering the reactor core reaches the design target of the reactor.)

1. The lower cavity structure of the reactor vessel is characterized by comprising a reactor core supporting bottom plate, a reactor vessel lower end enclosure and a reactor lower cavity inlet; the reactor core supporting bottom plate and the reactor vessel lower end enclosure enclose to form a lower cavity space;

the lower chamber structure further comprises a flow distribution plate circular plate located below the core support base plate;

the circular plate of the flow distribution plate is fixedly connected with the reactor core supporting bottom plate in parallel;

the radial width of the circular plate of the flow distribution plate is more than or equal to the diameter of a circular area with holes distributed on the reactor core supporting bottom plate, and the circular area is not contacted with the inside of the lower end enclosure of the reactor vessel;

the reactor lower cavity chamber inlet is arranged on the reactor container lower end enclosure in the area below the circular plate of the flow distribution plate;

the lower chamber structure further comprises a circular plate with an opening on the flow distribution plate, wherein the circular plate is located right below the circular plate of the flow distribution plate and fixedly connected with the circular plate of the flow distribution plate in parallel, the circular plate with the opening on the flow distribution plate is located in the space of the lower chamber, and the circular plate with the opening on the flow distribution plate is provided with a through hole.

2. The lower plenum structure of claim 1, wherein the core support floor has perforations corresponding to the core liquid fuel passages of the reactor vessel; preferably, the through holes on the core support bottom plate are arranged in an overall manner that a plurality of circles of concentric polygons are radially arranged from the center to the periphery; more preferably, the diameter of the perforation on the same circle is the same, and the diameter of the perforation is gradually reduced from the center to the outermost circle;

and/or the inner diameter of the inlet of the lower cavity of the reactor is 0.05D-0.1D, such as 0.075D, wherein D refers to the diameter of the circular area on the core support bottom plate distributed with holes;

and/or the reactor lower cavity chamber inlet is arranged at the bottom center of the reactor vessel lower end enclosure;

and/or the radial width of the circular plate of the flow distribution plate is smaller than that of the core support bottom plate.

3. The lower plenum structure of claim 1, wherein the vertical distance between the upper surface of the flow distribution plate circular plate and the lower surface of the core support floor is 0.02D-0.1D, such as 0.05D, D being the diameter of the circular area of the core support floor where the holes are distributed;

and/or the thickness of the flow distribution plate disk is 1-4cm, such as 2 cm;

and/or the diameter of the circular plate of the flow distribution plate is D-1.2D, such as 1.05D, wherein D refers to the diameter of the circular area on the core support bottom plate distributed with holes;

and/or the flow distribution plate circular plate and the core support bottom plate are coaxial;

and/or an opening circular plate on the flow distribution plate is coaxial with the flow distribution plate circular plate.

4. The lower chamber structure of claim 1, wherein the through hole of the perforated circular plate of the flow distribution plate is located at the center of the perforated circular plate of the flow distribution plate;

preferably, the radial width of the through hole is 1 to 1.5 times the inner diameter of the inlet of the lower reactor chamber, for example, 1.2 times the inner diameter of the inlet of the lower reactor chamber.

5. The lower chamber structure of claim 1, wherein the thickness of the perforated disc on the flow distribution plate is 0.5-1 times the thickness of the flow distribution plate disc, such as 0.5 times the thickness of the flow distribution plate disc;

and/or an opening circular plate on the flow distribution plate is not contacted with the inside of the lower seal head of the reactor vessel; preferably, the width of the gap between the edge of the circular plate with the holes on the flow distribution plate and the inside of the lower head of the reactor vessel is 0.01D-0.04D, for example 0.02D, where D is the diameter of the circular area on the core support bottom plate where the holes are distributed;

and/or the vertical distance between the lower surface of the circular plate of the flow distribution plate and the upper surface of the circular plate with the holes on the flow distribution plate is 0.01D-0.05D, such as 0.025D.

6. The lower chamber structure of claim 1, further comprising a lower perforated circular plate of the flow distribution plate directly below the upper perforated circular plate of the flow distribution plate and fixedly connected in parallel to the upper perforated circular plate of the flow distribution plate, wherein the lower perforated circular plate of the flow distribution plate is located in the lower chamber space, and the lower perforated circular plate of the flow distribution plate is provided with through holes;

preferably, the through hole of the lower perforated circular plate of the flow distribution plate is positioned at the center of the lower perforated circular plate of the flow distribution plate;

preferably, the radial width of the through hole of the circular plate of the lower opening of the flow distribution plate is 1 to 1.5 times the inner diameter of the inlet of the lower cavity of the reactor, for example, 1.2 times the inner diameter of the inlet of the lower cavity of the reactor;

preferably, the thickness of the lower opening circular plate of the flow distribution plate is 0.5 to 1 times, for example 0.5 times, the thickness of the circular plate of the flow distribution plate;

preferably, the circular plate of the lower opening of the flow distribution plate is not contacted with the inside of the lower seal head of the reactor vessel;

preferably, the width of the gap between the edge of the circular plate of the lower opening of the flow distribution plate and the inside of the lower head of the reactor vessel can be 0.01D-0.04D, such as 0.02D.

7. The lower chamber structure of claim 6, wherein the vertical distance between the lower surface of the upper apertured disc of the flow distribution plate and the upper surface of the lower apertured disc of the flow distribution plate is from 0.01D to 0.05D, such as 0.025D;

and/or the vertical distance between the lower surface of the circular plate with the lower opening of the flow distribution plate and the lowest point of the lower head of the reactor vessel is 0.03D-0.1D, such as 0.05D;

and/or the lower perforated circular plate of the flow distribution plate, the upper perforated circular plate of the flow distribution plate and the circular plate of the flow distribution plate are coaxial.

8. A lower chamber structure according to any of claims 1-7, characterized in that parallel fastening is achieved by means of several connecting pieces, for example 12.

9. The lower chamber structure according to claim 8, wherein the connecting member is provided in such a manner that: the connecting pieces are arranged in an inner circle and an outer circle.

10. A reactor vessel comprising a lower chamber structure according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of nuclear reactors, in particular to a lower cavity structure of a reactor vessel and the reactor vessel.

Background

The liquid fuel molten salt nuclear reactor body consists of a pressure vessel, an in-reactor graphite component and a metal component, wherein a reactor inlet is positioned at the bottom of a lower seal head of the pressure vessel, and an outlet is positioned at the top of an upper seal head of the pressure vessel; the fuel salt is melted in the carrier salt and flows along with the carrier salt, the fuel salt and the carrier salt fluid enter the reactor lower chamber from the bottom of the reactor vessel, then enter the reactor core through the reactor core lower support plate, and enter the upper chamber after fission energy is released in the reactor core flow channel formed by graphite, and then flow out from the outlet at the top of the upper chamber, so that heat transfer is realized (as shown in fig. 1).

Due to the characteristics of the liquid fuel nuclear reactor, the fuel power in the core active area is in a distribution form that the fuel power is gradually reduced in the central height radial direction in the whole reactor service life. Before entering the reactor core, the flow distribution form of the liquid fuel has important significance, and the flow distribution form is related to the smooth transfer of the fission energy of the reactor core, and directly determines the hot spot position of the reactor core and the size of the heat pipe factor, thereby directly relating to the safety of the whole reactor and even the whole nuclear power plant.

Because the lower end enclosure of the reactor vessel is generally in an (oval) spherical shape or a butterfly shape, and a lower cavity surrounded by the lower end enclosure and the lower support plate of the reactor core is approximately in a half (oval) spherical shape, when liquid fuel enters the lower cavity from the bottom of the lower end enclosure, the liquid fuel directly faces the lower support plate of the reactor core, and due to the fact that the flow direction is blocked, a large amount of vortexes can be generated in the lower cavity by the fluid, and the flow difference of the liquid fuel entering different pore channels of the reactor core is large. For a liquid fuel molten salt nuclear reactor, molten salt is used as fuel and has a heat source, and the vortex and the flow dead zone of the lower chamber not only cause flow instability, but also cause local high temperature, and influence the performance of a core material and the safety performance of the reactor. Therefore, when designing a nuclear reactor with an inlet positioned at the bottom of a lower head of a reactor vessel, a flow field regulation and core flow distribution structure needs to be arranged in a lower cavity below the core, so that fluid in the lower cavity is subjected to flow field regulation and the flow of the fluid entering a core channel is distributed, the fluid enters a core active area with acceptable flow distribution, and the loss of fluid pressure and the generation of vibration are reduced. Although the core flow distribution research and design of the early liquid fuel molten salt reactor inhibits the vortex and the flow dead zone of the lower chamber to a certain degree, and optimizes the core inlet flow distribution, the final design result is not ideal enough and does not reach the application degree on the reactor (see 'the core flow distribution design of the liquid fuel molten salt reactor', nuclear technology, 2016, 5 months, shahua, pandan and the like).

Disclosure of Invention

The invention provides a lower cavity structure of a reactor vessel and the reactor vessel, aiming at overcoming the defects that in the prior art, a large amount of vortexes are generated by fluid in a lower cavity of a reactor structure with an inlet positioned at the bottom of the reactor, and the flow difference of liquid fuel entering different pore passages of a reactor core is large and the liquid fuel is distributed unevenly.

The lower cavity structure of the reactor vessel regulates the flow of fluid entering the reactor core channel through flow field design and control and the structural arrangement of the flow distribution plate so as to meet the design requirement of flow distribution in the reactor core channel and realize the effects that no obvious vortex exists in the reactor and the flow distribution is accurately matched with the power distribution of the reactor core. The deviation of the power distribution of the flow distribution plate and the reactor core in the structural design can be reduced to be within 10 percent.

The invention solves the technical problems by the following scheme:

a lower cavity structure of a reactor vessel comprises a reactor core supporting bottom plate, a reactor vessel lower head and a reactor lower cavity inlet; the reactor core supporting bottom plate and the reactor vessel lower end enclosure enclose to form a lower cavity space;

the lower chamber structure further comprises a flow distribution plate circular plate located below the core support base plate;

the flow distribution plate circular plate and the reactor core supporting bottom plate are coaxially arranged and fixedly connected in parallel;

the radial width of the circular plate of the flow distribution plate is more than or equal to the diameter of a circular area with holes distributed on the reactor core supporting bottom plate, and the circular area is not contacted with the inside of the lower end enclosure of the reactor vessel;

the reactor lower cavity chamber inlet is arranged on the reactor container lower end enclosure in the area below the circular plate of the flow distribution plate;

the lower chamber structure further comprises a circular plate with an opening on the flow distribution plate, wherein the circular plate is located right below the circular plate of the flow distribution plate and fixedly connected with the circular plate of the flow distribution plate in parallel, the circular plate with the opening on the flow distribution plate is located in the space of the lower chamber, and the circular plate with the opening on the flow distribution plate is provided with a through hole.

In the present invention, preferably, the lower chamber structure further includes a lower perforated circular plate of the flow distribution plate, which is located right below the upper perforated circular plate of the flow distribution plate and is fixedly connected to the upper perforated circular plate of the flow distribution plate in parallel, the lower perforated circular plate of the flow distribution plate is located in the lower chamber space, and the lower perforated circular plate of the flow distribution plate is provided with a through hole.

In the present invention, the shape of the core support floor may be conventional in the art, such as a circle.

In the present invention, the core support bottom plate is preferably provided with a through hole corresponding to the position of the core liquid fuel passage of the reactor vessel, and the size of the through hole can be conventional in the art. The size of the through holes on the reactor core support bottom plate can be adjusted in different regions according to flow distribution requirements, and preferably, the through holes on the reactor core support bottom plate are arranged in an overall mode that a plurality of circles of concentric polygons are radially arranged from the center to the periphery. More preferably, the perforations in the same turn are of the same diameter and decrease in diameter from the center to the outermost turn.

In the present invention, the core support base plate may be conventional in the art, the core support base plate is generally provided with holes, the whole area in which the holes are distributed is a circular area, the diameter of the circular area is smaller than the diameter of the core support base plate, and the diameter of the circular area in which the holes are distributed on the core support base plate (i.e., the circular area in which the core channels are distributed as a whole) is denoted as D.

In the present invention, the shape of the inlet of the lower reactor chamber may be circular. The inner diameter of the inlet of the lower reactor chamber may be conventional in the art, preferably 0.05D to 0.1D, for example 0.075D, and may also be determined in conjunction with the loop plant interface.

In the invention, preferably, the reactor lower chamber inlet is arranged at the bottom center position of the reactor vessel lower end enclosure.

In the present invention, a vertical distance between an upper surface of the flow distribution plate circular plate and a lower surface of the core support base plate may be 0.02D to 0.1D, for example, 0.05D.

In the present invention, the thickness of the flow distribution plate can be conventional in the art, and is preferably 1-4cm, for example 2cm, and can also be given in combination with the structural member stress analysis result. The diameter of the flow distribution plate circular plate can be D-1.2D, e.g., 1.05D.

In the present invention, preferably, a radial width of the flow distribution plate circular plate is smaller than a radial width of the core support base plate.

In the present invention, preferably, the through hole of the perforated circular plate on the flow distribution plate is located at the center of the perforated circular plate on the flow distribution plate. The radial width of the through hole may be 1 to 1.5 times the inner diameter of the inlet of the lower reactor chamber, for example 1.2 times the inner diameter of the inlet of the lower reactor chamber.

In the present invention, the thickness of the perforated circular plate on the flow distribution plate may be 0.5 to 1 times, for example, 0.5 times, the thickness of the circular plate of the flow distribution plate. The circular plate with the opening on the flow distribution plate is preferably not contacted with the inside of the lower seal head of the reactor vessel; more preferably, the width of the gap between the edge of the circular plate with the opening on the flow distribution plate and the inside of the lower head of the reactor vessel can be 0.01D-0.04D, such as 0.02D.

In the present invention, preferably, the circular plate of the opening of the flow distribution plate and the circular plate of the flow distribution plate are coaxial.

In the present invention, the vertical distance between the lower surface of the flow distribution plate and the upper surface of the perforated plate on the flow distribution plate may be 0.01D to 0.05D, for example, 0.025D.

Wherein the through hole of the lower perforated circular plate of the flow distribution plate is preferably located at the center of the lower perforated circular plate of the flow distribution plate. The radial width of the through hole may be 1 to 1.5 times the inner diameter of the inlet of the lower reactor chamber, for example 1.2 times the inner diameter of the inlet of the lower reactor chamber.

Preferably, the lower perforated circular plate of the flow distribution plate, the upper perforated circular plate of the flow distribution plate and the circular plate of the flow distribution plate are coaxial.

Wherein, the thickness of the lower opening circular plate of the flow distribution plate can be 0.5 to 1 times of the thickness of the circular plate of the flow distribution plate, for example 0.5 times. The circular plate with the lower opening of the flow distribution plate is preferably not contacted with the inside of the lower seal head of the reactor vessel; more preferably, the width of the gap between the edge of the circular plate of the lower opening of the flow distribution plate and the inside of the lower head of the reactor vessel can be 0.01D-0.04D, such as 0.02D.

Wherein the vertical distance between the lower surface of the upper orifice plate of the flow distribution plate and the upper surface of the lower orifice plate of the flow distribution plate may be 0.01D to 0.05D, for example 0.025D.

Wherein, the vertical distance between the lower surface of the circular plate of the lower opening of the flow distribution plate and the lowest point of the lower seal head of the reactor vessel can be 0.03D-0.1D, such as 0.05D.

In the invention, by adjusting the vertical distance between the circular plate of the flow distribution plate and the circular plates of the upper opening and the lower opening of the flow distribution plate, the vortexes and the flow dead zones in the lower chamber can be effectively inhibited, and the flow of the fluid entering the core channel can be better adjusted by combining the size partition change of the opening on the core support plate.

Wherein, according to the requirement, a plurality of flow distribution plate perforated circular plates can be arranged under the flow distribution plate perforated circular plate.

In a preferred embodiment of the present invention, the lower chamber structure comprises a core support floor, the reactor vessel lower head, and a reactor lower chamber inlet; the reactor core supporting bottom plate and the reactor vessel lower end enclosure enclose to form a lower cavity space;

the lower chamber structure further comprises a flow distribution plate circular plate located below the core support base plate;

the circular plate of the flow distribution plate is fixedly connected with the reactor core supporting bottom plate in parallel;

the radial width of the circular plate of the flow distribution plate is smaller than that of the reactor core support bottom plate;

the radial width of the circular plate of the flow distribution plate is more than or equal to the diameter of a circular area with holes distributed on the reactor core supporting bottom plate, and the circular area is not contacted with the inside of the lower end enclosure of the reactor vessel;

the reactor lower cavity chamber inlet is arranged on the reactor container lower end enclosure in the area below the circular plate of the flow distribution plate;

the lower chamber structure also comprises a circular plate with an opening on the flow distribution plate, which is positioned right below the circular plate of the flow distribution plate and is fixedly connected with the circular plate of the flow distribution plate in parallel, and the circular plate with the opening on the flow distribution plate is provided with a through hole;

the lower chamber structure also comprises a flow distribution plate lower opening circular plate which is positioned right below the flow distribution plate upper opening circular plate and fixedly connected with the flow distribution plate upper opening circular plate in parallel, and the flow distribution plate lower opening circular plate is provided with a through hole.

In the present invention, the parallel fastening can be performed by a conventional connecting method in the art, such as welding or bolts, and is preferably performed by a plurality of connecting members, such as 12 connecting members, disposed on the circular plate of the flow distribution plate, the circular plate with holes opened on the flow distribution plate, and the circular plate with holes opened on the lower portion of the flow distribution plate.

Wherein the number and size of the connectors are adjustable according to the reactor size. The connecting piece setting mode preferably is: the connecting pieces are distributed in an inner circle and an outer circle, for example, 4 inner circles are arranged at the position R/3 away from the center of the flow distribution plate and are uniformly distributed at intervals of 90 degrees; the outer rings are 8, are 2R/3 away from the center of the distribution plate and are uniformly distributed at intervals of 45 degrees, wherein R refers to the radius of the flow distribution plate.

According to the invention, the flow distribution structure of the lower cavity structure can ensure the matching of the flow distribution result and the power distribution of the molten salt channel of the reactor core, the deviation between the flow distribution result of the reactor core and the power distribution of the reactor core realized by the lower cavity structure can be reduced to be within 10%, and the smaller the deviation is, the better the flow distribution effect is; wherein the core radial power generally refers to the core radial typical power distribution at different burn-up times of the life of the molten salt reactor vessel.

In the invention, the core flow distribution uniformity coefficient realized by the lower cavity structure can reach 0.2-2, wherein the core flow distribution uniformity coefficient is a parameter reflecting the distribution result of the flow in all channels of the core, the core flow distribution uniformity coefficient refers to the ratio of the flow in a certain channel to the average flow of all channels, and is a quantity expressing the relative size of the channel flow, and the uniformity coefficient of all channels expresses the trend of the flow distribution.

The invention also provides a reactor vessel comprising the lower chamber structure.

On the basis of the common knowledge in the field, the above preferred conditions can be combined randomly to obtain the preferred embodiments of the invention.

The reagents and starting materials used in the present invention are commercially available.

The positive progress effects of the invention are as follows:

1) according to the lower cavity structure, the shape of the coolant channel is changed through the flow distribution plate circular plate, the flow field characteristic of the lower cavity is effectively improved, the vortex in the lower cavity is avoided, and the flow distribution is performed on the fluid through the reactor core lower support plate, so that the flow distribution of the fluid entering the reactor core reaches the design target of the reactor;

2) the core flow distribution uniformity coefficient realized by the lower cavity structure is matched with the radial power distribution of the liquid fuel molten salt reactor core and can reach 0.2-2;

3) the deviation between the reactor core flow distribution and the reactor core power distribution realized by the lower chamber structure can be reduced to be within 10 percent.

Drawings

Fig. 1 is a schematic view of a reactor vessel and its internal fluid flow fields.

FIG. 2 is a schematic diagram showing the distribution of core support floor openings in the present invention.

FIG. 3 is a schematic view of the core flow distribution structure according to the present invention in embodiments 1 to 2.

FIG. 4 is a schematic structural view of a core support base plate and a flow distribution plate corresponding to the core flow distribution structures in embodiments 1 to 2.

Wherein: 10-a reactor vessel; 11-reactor lower chamber inlet; 12-reactor lower chamber; 13-core support floor; 14-a reactor core structure; 15-reactor upper chamber; 16-reactor outlet; 17-core channel; 20-reactor vessel lower head; 21-a flow distribution plate circular plate; 22-an opening circular plate on the flow distribution plate; 23-a circular plate with a hole below the flow distribution plate; 24-a flow distributor plate connection; 25-through holes of the upper and lower opening circular plates of the flow distribution plate.

Detailed Description

The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention. Experimental procedures without specifying specific conditions in the following examples were carried out according to conventional methods and conditions.