Reactor pit structure of pool type reactor

Abstract

The invention provides a pool type reactor pit structure, and relates to the technical field of nuclear reactors, the pool type reactor pit structure comprises a reactor pit, an upper component, an air inlet channel and at least two air exhaust channels, the top surface of a shielding body of the reactor pit is recessed inwards to form the reactor pit so as to accommodate a pressure vessel; the upper component is fixedly arranged on the top surface of the shielding body and seals the opening of the reactor pit, and a fluid space is defined among the upper component, the cavity wall of the reactor pit and the pressure container; the air inlet channel is bent outwards from the upper part of the shielding body and extends to penetrate through the lower cavity wall of the reactor pit; the exhaust channel bends and extends out of the top surface of the shielding body to penetrate through the upper cavity wall of the reactor pit; all the exhaust channels are uniformly arranged on one side of the central axis of the reactor pit, and the air inlet channel is arranged on the other side of the central axis of the reactor pit. According to the reactor pressure vessel, direct penetration of a shielding body is avoided, leakage of radioactive substances in the reactor can be stopped, 360-degree enveloping ventilation of the reactor pressure vessel is achieved, the reactor pressure vessel can be continuously cooled, and the heat dissipation effect is better.

Description

Technical Field

[0001] The present application relates to the technical field of nuclear reactors, and in particular to a pool-type reactor pit structure. Background Art

[0002] The pool-type reactor pit structure is used to install the reactor pressure vessel. It is generally formed by an axial straight-through concave shape from the top surface of the shielding body. The pit mouth is closed by the upper component. A fluid space is defined between the cavity wall of the pit and the reactor pressure vessel and the upper component.

[0003] The pit structure includes an air inlet channel and an air exhaust channel for ventilating the fluid space and the outside of the pit to cool the reactor pressure vessel. In the existing pit structure, the air inlet channel and the air exhaust channel generally directly penetrate the entire biological shielding layer outside the pit. The air inlet channel and the air exhaust channel in this application adopt a straight-through pipeline structure design. The radioactive materials in the pit can easily leak out of the pit through the air inlet channel and the air exhaust channel, which poses a safety risk of neutron leakage.

[0004] In addition, in the existing reactor pit structure, the fluid space defined between the straight-through reactor pit cavity and the upper components and the reactor pressure vessel is limited, and the filling amount of gaseous medium and liquid medium in the fluid space is not high, and the cooling effect on the reactor pressure vessel is not significant. Summary of the invention

[0005] The present application provides a pool-type reactor pit structure, which is used to solve the technical problems that the existing pool-type reactor pit structure has an unreasonable structural design, the radioactive materials inside the pit are easy to leak out from the air inlet channel and the air exhaust channel, and the cooling effect on the pressure vessel is not significant. The pool-type reactor pit structure provided by the present application can stop the leakage of radioactive materials in the reactor through multiple inflection points on the ventilation path, and can form 360° envelope ventilation for the reactor pressure vessel, which has a better cooling effect on the pressure vessel.

[0006] In some embodiments of the present application, a pool-type reactor pit structure is provided, the pit structure comprising: a pit, which is formed by being recessed inward from the top surface of a shielding body to accommodate a pressure vessel; an upper member, which is fixed to the top surface of the shielding body and closes the pit opening of the pit, a fluid space being defined between the upper member, the cavity wall of the pit, and the pressure vessel; an air inlet channel, which extends in a zigzag manner from the outside of the shielding body to the lower cavity wall penetrating the pit, so as to supply air into the fluid space; at least two exhaust channels, which extend in a zigzag manner from the outside of the top surface of the shielding body to the upper cavity wall penetrating the pit, so as to exhaust air out of the fluid space; all of the exhaust channels are evenly arranged on one side of the central axis of the pit, and the air inlet channels are arranged on the other side of the central axis of the pit.

[0007] In some embodiments, each of the air inlet channels includes a first section, at least one second section, and a third section connected in sequence, wherein: the first section is horizontally extended along a first direction, and the end of the first section away from the stack pit passes through the outer wall of the shielding body; the third section is horizontally extended along a second direction, and the end of the third section toward the stack pit passes through the lower cavity wall; the height of the first section in the axial direction of the stack pit is greater than that of the third section, the second section connects the first section and the third section, and the first direction is different from the second direction.

[0008] In some embodiments, a projection of the entire exhaust passage on the top surface of the shielding body has a symmetry axis extending in a radial direction of the stack pit, and a projection of the third section on the top surface of the shielding body is located on the symmetry axis.

[0009] In some embodiments, each of the exhaust passages includes a fourth section and a fifth section connected in sequence, wherein: the fourth section extends along the radial direction of the stack pit, and the fourth section passes through the upper cavity wall toward one end of the stack pit; the fifth section extends along the axial direction of the stack pit, and the fifth section passes through the top surface of the shielding body at one end away from the stack pit; the fifth section is vertically connected to the fourth section.

[0010] In some embodiments, the stack pit includes a main body section, a connecting section, and a pit mouth section connected by coaxial lines, the inner diameter of the main body section is larger than the inner diameter of the pit mouth section, the connecting section connects the main body section with the pit mouth section, and the pit mouth section forms a pit mouth of the stack pit on the top surface of the shielding body; the upper cavity wall and the lower cavity wall are both located on the main body section; the upper component includes an upper supporting structure, the upper supporting structure at least partially presses against the periphery of the pit mouth, and the pressure vessel and / or the thermal insulation layer provided outside the pressure vessel at least partially presses against the upper supporting structure.

[0011] In some embodiments, the upper component further includes a primary shield, which covers the upper support structure, the pressure vessel and / or the insulation layer and closes the stack pit.

[0012] In some embodiments, the stack pit structure also includes: a coolant injection channel, which extends in a zigzag manner from the lower outside of the shielding body to the lower cavity wall passing through the stack pit, so as to inject coolant into the fluid space in an emergency situation, and the injected coolant is poured onto the top surface of the shielding body through the exhaust channel.

[0013] In some embodiments, inner diameters of the coolant injection channel and the exhaust channel are both smaller than the inner diameter of the air inlet channel.

[0014] In some embodiments, the stack pit structure further includes: a working platform fixed on the top surface of the shielding body, and having a central opening through which the upper member is exposed, and at least two exploration holes surrounding the periphery of the central opening;

[0015] At least two detection channels are bent and extended from the top surface of the shielding body to the cavity wall penetrating the stack pit, and are arranged around the circumference of the stack pit; the detection channel is formed with a detector entrance on the top surface of the shielding body, and the detector entrance is connected one-to-one with the exploration hole so that the detector can be lowered into the detection channel through the exploration hole and the detector entrance.

[0016] In some embodiments, each of the detection channels includes a sixth section and a seventh section connected in sequence, wherein:

[0017] The sixth section is arranged to extend in an arc shape from the top surface of the shielding body at the outer side of the upper component and along the axial direction of the stack pit toward one side close to the upper cavity wall;

[0018] The seventh section is connected to the sixth section, and the seventh section extends along the axial direction of the stack pit toward one end of the top surface away from the shielding body; the seventh section penetrates the cavity wall of the stack pit toward one side of the stack pit and forms a detection window, and the cross-section of the detection window perpendicular to the central axis is an outward-expanding trumpet-mouth structure.

[0019] The pool-type reactor pit structure provided by the present application includes a pit, an upper component, an air inlet channel, and at least two exhaust channels. The reactor pressure vessel is installed in the pit, and the upper component is fixed to the top surface of the shielding body and closes the pit mouth of the pit, and a fluid space is defined between the upper component, the cavity wall of the pit, and the pressure vessel. The air inlet channel extends from the upper outer portion of the shielding body to the lower cavity wall penetrating the pit, and is used to supply air to the fluid space; at least two exhaust channels extend from the top outer portion of the shielding body to the upper cavity wall penetrating the pit, and are used to exhaust air outside the fluid space.

[0020] The tortuously extending air inlet channel and exhaust channel together constitute a labyrinth-like ventilation path in the reactor pit structure for the internal and external circulation of the gas medium in the fluid space, and multiple turning points are formed on the air inlet channel and the exhaust channel. Compared with the channel structure extending in a straight path on the existing reactor shielding body, the improved ventilation path of the reactor pit structure of the present application avoids direct penetration of the shielding body, meets the safety requirements for perforation of the biological shielding layer of the reactor wall, and can stop the leakage of radioactive materials in the reactor through multiple turning points on the ventilation path, thus solving the problem of leakage of radioactive materials in the reactor pit caused by the existing reactor pit air inlet channel directly penetrating the entire biological shielding layer.

[0021] In addition, all the exhaust channels in the pit structure of the present application are evenly arranged on one side of the central axis of the pit, and the air inlet channels are arranged on the other side of the central axis of the pit, so that the external airflow can enter through the air inlet channel at the lower cavity wall of the pit, close to the bottom of the pit, and then flow around the pressure vessel to the circumferential sides of the inner cavity of the pit, and finally be discharged upward from the multiple exhaust channels on the upper cavity wall of the pit, thereby realizing 360° envelope ventilation of the reactor pressure vessel, being able to continuously cool the reactor pressure vessel, and achieving better heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work, including:

[0023] Figure 1 A schematic cross-sectional view of the overall structure of a specific embodiment of the stack pit structure of the present application;

[0024] Figure 2 for Figure 1 A schematic cross-sectional view of the structure with the upper components and the working platform hidden;

[0025] Figure 3 This is a schematic top view of a specific embodiment of the stack pit structure of the present application with the upper components and the working platform hidden;

[0026] Figure 4 This is a schematic diagram of the three-dimensional structure of a specific embodiment of the stack pit structure of the present application after hiding the upper components and the working platform. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. According to the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application. In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementation methods. At the same time, the steps or actions in the method description can also be swapped or adjusted in order in a manner that is obvious to those skilled in the art. Therefore, the various orders in the specification and the accompanying drawings are only for the purpose of clearly describing a certain embodiment, and do not mean that it is a necessary order, unless otherwise specified that a certain order must be followed.

[0028] See also Figures 1 to 3In some embodiments of the present application, a pool-type reactor pit structure is provided, which is used in a reactor containment vessel 100. The pit structure includes a pit 1, an upper component 2, an air inlet channel 3, and at least two exhaust channels 4, wherein the pit 1 is formed by being recessed inward from the top surface 101 of the shielding body 10, and is used to accommodate a pressure vessel 5. The upper component 2 is fixedly connected to the top surface 101 of the shielding body 10 and closes the pit mouth 131 of the pit 1, and a fluid space 6 is defined between the upper component 2, the cavity wall of the pit 1, and the pressure vessel 5. The shielding body 10 is a bottom component of the reactor containment vessel 100, which is used to form the pit 1, and plays a supporting role for the internal equipment of the pit 1, and can prevent the radioactive substances in the pit 1 from leaking to the outside. In this application, the concrete shielding body 10 is used as an example for explanation.

[0029] The fluid space 6 mentioned in the present application refers to a space with a certain volume that can be filled with a fluid medium and allows the fluid medium to flow. The fluid medium can be either a gas, such as air, or a liquid, such as water. The specific type of the fluid medium can be selectively filled according to the actual operation of the reactor.

[0030] The air inlet channel 3 extends from the outside of the shielding body 10 to the lower cavity wall of the stack pit 1 near its bottom surface, so as to supply air to the fluid space 6. The exhaust channel 4 extends from the outside of the top surface 101 of the shielding body 10 to the upper cavity wall of the stack pit 1 near its pit opening 131, so as to exhaust air outside the fluid space 6. All the exhaust channels 4 are evenly arranged on one side of the central axis 104 of the stack pit 1, and the air inlet channels 3 are arranged on the other side of the central axis 104 of the stack pit 1. In this embodiment, all the exhaust channels 4 are evenly arranged on the left side of the central axis 104 of the stack pit 1, and the air inlet channels 3 are arranged on the right side of the central axis 104 of the stack pit 1.

[0031] In the present application, the shield 10 is described by taking a cubic concrete shield 10 as an example. The pit 1 is preferably formed by being recessed from the middle of the top surface 101 of the shield 10 to the inside of the shield 10, so that a concrete biological shielding layer outside the pit 1 is formed between the cavity wall of the pit 1 and the outer wall of the shield 10. The concrete biological shielding layer includes a bottom biological shielding layer outside the bottom of the pit 1 and a side biological shielding layer outside the cavity wall of the pit 1. The thickness of the bottom biological shielding layer and the side biological shielding layer must meet the safety shielding requirements. The ventilation paths of the air inlet channel 3 and the exhaust channel 4 are both in the side biological shielding layer.

[0032] The pool-type reactor pit structure provided by the present application comprises a zigzag air inlet channel 3 and an exhaust channel 4 which together constitute a labyrinth-like ventilation path in the pit 1 structure for the internal and external circulation of the gas medium in the fluid space 6, and a plurality of inflection points are formed on the air inlet channel 3 and the exhaust channel 4. Compared with the channel structure extending in a straight path on the existing reactor shielding body 10, the improved ventilation path of the pit 1 structure of the present application avoids direct penetration of the side biological shielding layer of the shielding body 10, meets the safety requirements for perforation of the biological shielding layer of the reactor wall, and can stop the leakage of radioactive substances in the reactor through the plurality of inflection points on the ventilation path, thereby solving the problem of leakage of radioactive substances in the pit 1 caused by the air inlet channel 3 of the existing pit 1 directly penetrating the entire biological shielding layer, and having higher safety.

[0033] In addition, all the exhaust channels 4 in the structure of the pit 1 of the present application are evenly arranged on one side of the central axis 104 of the pit 1, and the air inlet channels 3 are arranged on the other side of the central axis 104 of the pit 1, so that the external airflow can enter through the air inlet channels 3 at the lower cavity wall of the pit 1, close to the bottom of the pit 1, and then flow around the pressure vessel 5 to the circumferential sides of the inner cavity of the pit 1, and finally be discharged upward from the multiple exhaust channels 4 on the upper cavity wall of the pit 1, thereby realizing 360° envelope ventilation of the reactor pressure vessel 5, being able to continuously cool the reactor pressure vessel 5, and achieving better ventilation and heat dissipation effects.

[0034] See also Figures 2 to 3 In some embodiments, each air inlet channel 3 includes a first section 31, at least one second section 32, and a third section 33 connected in sequence, wherein the first section 31 is horizontally extended along the first direction, and the outer end of the first section 31 away from the stack pit 1 penetrates the outer wall of the shielding body 10 to form an outer air inlet 311, and the outer air inlet 311 is connected to the air blowing device upstream of the stack pit cooling system, and is used for the low-temperature airflow to enter the air inlet channel 3. The third section 33 is horizontally extended along the second direction, and the inner end of the third section 33 toward the stack pit 1 penetrates the lower cavity wall of the stack pit 1 to form an inner air inlet 331 close to the bottom of the stack pit 1, and the inner air inlet 331 is connected to the fluid space 6, and is used for the low-temperature airflow to enter the fluid space 6 from the other side of the central axis 104 of the stack pit 1 and close to the bottom of the stack pit 1. The height of the first section 31 in the axial direction of the stack pit 1 is greater than the height of the third section 33 in the axial direction of the stack pit 1 , the second section 32 connects the first section 31 and the third section 33 , and the first direction is different from the second direction.

[0035] Since the first section 31 and the third section 33 are both horizontally extended, and the height of the first section 31 in the axial direction of the pit 1 is greater than the height of the third section 33 in the axial direction of the pit 1, the first section 31 is located above the third section 33 in the vertical direction, and there is a certain distance between the outer end of the first section 31 inside the side shielding layer and the inner end of the third section 33 inside the side shielding layer in the axial direction of the pit 1, so that the second section 32 connects the first section 31 and the third section 33 at least in the vertical plane. In addition, the first direction is different from the second direction, so that the air inlet channel 3 can form a ventilation path that tortuously extends in a three-dimensional space in the side shielding layer.

[0036] In this embodiment, the second section 32 is set as a separate section for explanation, so that the total length of the ventilation path of the air inlet channel 3 can be shortened, the difficulty of the perforation operation of the shielding body 10 can be reduced, and air can be quickly supplied to the fluid space 6. When the outer end of the first section 31 inside the side shielding layer and the inner end of the third section 33 inside the side shielding layer are on the same vertical line, the second section 32 is set in the vertical direction and connects the first section 31 and the third section 33, so that the total length of the ventilation path of the air inlet channel 3 is the shortest, and the air inlet channel 3 constitutes a ventilation path that is approximately Z-shaped and tortuous in three-dimensional space. When the radioactive material inside the pile pit 1 enters the air inlet channel 3 through the inner air inlet 331, it will be stopped twice at least by the inflection point at the connection between the third section 33 and the second section 32 and the inflection point at the connection between the second section 32 and the first section 31, which significantly reduces the risk of radioactive material leaking out through the air inlet channel 3.

[0037] In some other embodiments, the second section 32 may also be configured as a plurality of sections extending and connected in different directions, which can increase the number of turning points in the air inlet channel 3 and improve the blocking effect on the radioactive material inside the pit 1, but at the same time, the total length of the ventilation path will be increased and the difficulty of punching the shield 10 will be increased. In actual manufacturing, the number of second sections 32 and the extension direction of each second section 32 can be adjusted accordingly according to actual needs.

[0038] See also Figure 3 In some embodiments, the projections of all the exhaust channels 4 on the top surface 101 of the shielding body 10 have a symmetry axis 105 extending along the radial direction of the reactor pit 1, and the projection of the third section 33 of the air inlet channel 3 on the top surface 101 of the shielding body 10 is located on the symmetry axis 105. In this way, the inner air inlet 331 formed by the third section 33 penetrating the lower cavity wall of the reactor pit 1 is relatively located at the middle lower side of each exhaust channel 4, and the airflow entering the fluid space 6 through the inner air inlet 331 can be evenly diverted to both sides of the inner cavity of the reactor pit 1 and discharged through each exhaust channel 4, thereby ensuring uniform heat dissipation of the reactor pressure vessel 5 and further improving the heat dissipation effect.

[0039] Furthermore, the first section 31 of the air inlet channel 3 is preferably arranged to be perpendicular to the third section 33, and the projections of the first section 31 and the third section 33 on the top surface 101 of the shielding body 10 are connected at right angles, and the second section 32 is arranged in the vertical direction and vertically connects the first section 31 and the third section 33.

[0040] In order to facilitate understanding of the structure of the air inlet channel 3 in three-dimensional space, the second direction in which the third section 33 extends is marked as the X-axis direction, the first direction in which the first section 31 extends is marked as the Y-axis direction, and the vertical direction in which the second section 32 extends is marked as the Z-axis direction. At this time, the structure of the air inlet channel 3 in three-dimensional space is that the first section 31 extends along the Y-axis direction, the third section 33 extends along the X-axis direction, and the second section 32 extends along the Z-axis direction and connects the first section 31 and the third section 33.

[0041] In addition, each section of the air inlet channel 3 should meet the safety shielding requirements of the perforation of the biological shielding layer, wherein the vertical distance between the first section 31 and the top surface of the side biological shielding layer (i.e., the top surface 101 of the shielding body 10, which will not be repeated below) cannot be less than 1.5m, and is preferably between 1.5m and 3m; the vertical distance between the second section 32 and the outer wall surface of the side biological shielding layer (i.e., the outer wall surface of the shielding body 10, which will not be repeated below) cannot be less than 1.5m, and is preferably between 1.5m and 3m; the vertical distance between the third section 33 and the bottom surface of the bottom biological shielding layer (i.e., the bottom wall surface of the shielding body 10, which will not be repeated below) cannot be less than 1.5m, and is preferably between 1.5m and 3m.

[0042] See also Figure 1 to Figure 2 In some embodiments, each exhaust passage 4 includes a fourth section 41 and a fifth section 42 connected in sequence, wherein the fourth section 41 is extended along the radial direction of the pit 1, and the fourth section 41 penetrates the upper cavity wall of the pit 1 toward the inner end of the pit 1, and forms an inner exhaust port 411, which is connected to the fluid space 6, and the hot air flow for heat exchange and heating in the pit 1 enters the exhaust passage 4 from one side of the central axis 104 of the pit 1, near the pit opening 131 of the pit 1. The fifth section 42 is extended along the axial direction of the pit 1, that is, the vertical direction, and the fifth section 42 penetrates the top surface 101 of the shielding body 10 upward away from the outer end of the pit 1, and forms an outer exhaust port 421, which is connected to the hot air recovery and purification treatment equipment downstream of the pit cooling system, and is used to recover and treat the discharged hot air flow. The fifth section 42 is vertically connected to the fourth section 41.

[0043] The present application sets the exhaust channel 4 to include a fourth section 41 and a fifth section 42 connected vertically, so that the total length of the ventilation path of the exhaust channel 4 can be shortened, the difficulty of the perforation operation of the shielding body 10 can be reduced, and it is conducive to the rapid discharge of the hot air flow after heat exchange and heating in the fluid space 6. When the fifth section 42 is vertically connected to the fourth section 41, the total length of the ventilation path of the exhaust channel 4 is the shortest, and the exhaust channel 4 forms a ventilation path that is approximately L-shaped and tortuous in the vertical plane. When the radioactive material inside the pile pit 1 enters the corresponding exhaust channel 4 through the internal exhaust port 411, it will at least be stopped by the inflection point at the connection between the fourth section 41 and the fifth section 42, which significantly reduces the risk of radioactive material leaking out through the exhaust channel 4.

[0044] See also Figure 2 In some embodiments, the stack pit 1 includes a main body section 11, a connecting section 12, and a pit mouth section 13 connected coaxially from the bottom to the pit mouth 131. The inner diameter of the main body section 11 is larger than the inner diameter of the pit mouth section 13. The connecting section 12 connects the main body section 11 and the pit mouth section 13. The pit mouth section 13 forms the pit mouth 131 of the stack pit 1 on the top surface 101 of the shield 10. The upper cavity wall and the lower cavity wall of the stack pit 1 are both located on the main body section 11, so that the length of the inner wall surface of the pit mouth section 13 in the axial direction of the stack pit 1 is significantly smaller than the length of the inner wall surface of the main body section 11 in the axial direction of the stack pit 1. Since the inner diameter of the main body section 11 is larger than the inner diameter of the pit mouth section 13, the diameter of the inner wall surface of the connecting section 12 gradually decreases from the main body section 11 to the pit mouth section 13 and forms a slope extending downward, so that a similar corner-cutting bracket structure is formed at the pit mouth 131 of the stack pit 1 of the present application.

[0045] See also Figure 1 , the upper member 2 includes an upper support structure 21, the upper support structure 21 at least partially presses against the periphery of the pit opening 131 of the reactor pit 1, and the pressure vessel 5 and / or the insulation layer 51 arranged outside the pressure vessel 5 at least partially presses against the upper support structure 21. The outside of the reactor pressure vessel 5 is generally provided with an insulation layer 51 for heat preservation, and the main body of the pressure vessel 5 is accommodated in the inner cavity of the insulation layer 51. After installation, the fluid space 6 can be defined between the insulation layer 51 and the cavity wall of the reactor pit 1 and the upper member 2. During installation, the mounting flange at the top of the pressure vessel 5 is seated on the upper support structure 21, and the two are locked and fixed by fasteners. Preferably, the top periphery of the insulation layer 51 is at least partially fixedly connected to the upper support structure 21 together with the pressure vessel 5, so that the pressure vessel 5 and the insulation layer 51 are fixed together in the reactor pit 1 through the upper support structure 21.

[0046] The connection section 12 and the pit mouth section 13 of the stack pit 1 of the present application are combined with the concrete shield 10 to bear the upper component 2, the pressure vessel 5, the insulation layer 51 and related auxiliary loads. Compared with the straight-through inner cavity structure of the stack pit in the existing design, the inner cavity diameter of the main section 11 of the stack pit 1 of the present application is larger than the inner cavity diameter of the pit mouth section 13, which satisfies the pressure vessel 5 and the insulation layer 51 to be lifted and installed in the stack pit 1 through the pit mouth 131, while significantly increasing the distance between the inner wall surface of the main section 11 and the outer insulation layer 51 of the pressure vessel 5, thereby increasing the volume of the fluid space 6 defined between the inner wall surface of the main section 11 and the outer insulation layer 51 of the pressure vessel 5, which can further increase the amount of fluid medium filled in the fluid space 6, improve the heat exchange efficiency between the fluid medium and the pressure vessel 5, and further improve the ventilation and heat dissipation effects of the pressure vessel 5.

[0047] In some embodiments, after the reactor pressure vessel 5 and the insulation layer 51 are installed, the vertical distance between the inner wall surface of the pit mouth section 13 and the outer insulation layer 51 of the reactor pressure vessel 5 is less than 10 cm, preferably set to 5-7 cm; the vertical distance between the inner wall surface of the main body section 11 and the outer insulation layer 51 of the reactor pressure vessel 5 is more than 10 cm, preferably set to 20-40 cm, so that the volume of the defined fluid space 6 can meet the ventilation and heat dissipation requirements of the reactor pressure vessel 5 and the water injection volume requirements of the pit 1 when an accident occurs.

[0048] The height of the inner wall surface of the pit mouth section 13 in the axial direction of the pile pit 1 and the height of the inner wall surface of the connecting section 12 in the axial direction of the pile pit 1 are based on ensuring that the cut-angle bracket structure at the pit mouth 131 can bear the total weight of the pool-type reactor upper components 2, the pressure vessel 5, the insulation layer 51 and various related load weights, which can be obtained through computer calculation through force analysis of the pit mouth section 13 and the connecting section 12.

[0049] In some embodiments, in order to improve the stability and reliability of the fixation of the reactor pressure vessel 5 in the reactor pit 1, a lower supporting structure (not shown) fixed on the bottom surface of the reactor pit 1 or an auxiliary supporting structure in the pit (not shown) can be used to cooperate with the upper supporting structure 21 to support and fix the insulation layer 51 and the pressure vessel 5.

[0050] See also Figure 1 In some embodiments, the upper member 2 further includes a primary shield 22, which covers the upper support structure 21, the pressure vessel 5 and the insulation layer 51 and seals the reactor pit 1. The primary shield 22 seals the reactor pit 1 from the outside to prevent the radioactive materials in the reactor pit 1 from directly leaking into the reactor containment vessel 100 through the pit opening 131.

[0051] See also Figures 1 to 3In some embodiments, the structure of the reactor pit 1 of the present application further includes a coolant injection channel 7, which extends in a zigzag manner from the lower outer portion of the shielding body 10 near the bottom of the reactor pit 1 to the lower cavity wall of the reactor pit 1 near its bottom surface, so that in an emergency such as a safety accident in the reactor, coolant can be injected into the fluid space 6 through the coolant injection channel 7, and the injected coolant can be poured onto the top surface 101 of the shielding body 10 through the exhaust channel 4, ensuring that the amount of the injected coolant can meet the requirements of unattended operation and intervention for at least three days, so that the heat in the reactor pit 1 can be taken away in time by the coolant, and the high-temperature molten material in the pressure vessel 5 can be prevented from melting through the lower head of the vessel and entering the reactor pit 1.

[0052] See also Figure 1 In some embodiments, the upper support structure 21 has a certain height in the axial direction of the reactor pit 1, which can at least partially "push" the top of the reactor pressure vessel 5 out of the pit opening 131 of the reactor pit 1, and form a certain distance between the top surface 101 of the concrete shield 10 and the end surface of the mounting flange at the top of the pressure vessel 5. This distance can further increase the volume of the fluid space 6 to a certain extent, ensuring that a sufficient amount of fluid medium such as cold air flow and coolant can be filled in the fluid space 6.

[0053] The coolant is preferably cooling water, which can significantly reduce the cost of the coolant.

[0054] In some embodiments, the inner diameters of the coolant injection channel 7 and the exhaust channel 4 are both smaller than the inner diameter of the air inlet channel 3 .

[0055] See also Figures 1 to 3 In a specific embodiment, a coolant injection channel 7 is provided in the structure of the pile pit 1. The coolant injection channel 7 is zigzag-extended on a horizontal plane close to the bottom of the pile pit 1 and is arranged on the right side of the central axis 104 of the pile pit 1. The coolant injection channel 7 includes a first injection section 71 and a second injection section 72 connected in sequence, and the first injection section 71 and the second injection section 72 are connected at an angle. Among them, the first injection section 71 extends from the lower part of the concrete shielding body 10 close to the bottom of the pile pit 1 and is parallel to the third section 33 of the air inlet channel 3, and the outer end of the first injection section 71 away from the pile pit 1 passes through the lower outer wall of the shielding body 10 and forms an external liquid inlet 711, which is connected to the water injection tank and other related equipment upstream of the pile pit cooling system for the coolant to enter the coolant injection channel 7. The second injection section 72 is extended in the radial direction of the stack pit 1, and the second injection section 72 passes through the lower cavity wall of the stack pit 1 close to its bottom surface toward the inner end of the stack pit 1 to form an inner liquid inlet 721, and the inner liquid inlet 721 is connected to the fluid space 6, so as to allow the cooling liquid to enter the fluid space 6 from the right side of the central axis 104 of the stack pit 1 and close to the bottom of the stack pit 1.

[0056] The inner liquid inlet 721 is closer to the bottom surface of the stack pit 1 than the inner air inlet 331 , and the inner liquid inlet 721 and the inner air inlet 331 are offset from each other in the axial direction of the stack pit 1 to avoid interference between the coolant injection channel 7 and the air inlet channel 3 .

[0057] The first injection section 71 and the second injection section 72 of the coolant injection channel 7 are connected at an angle, so that the radioactive material entering through the inner liquid inlet 721 will at least be stopped by the inflection point at the connection between the first injection section 71 and the second injection section 72, preventing the radioactive material from leaking out through the coolant injection channel 7.

[0058] See also Figure 1 In some embodiments, the pile pit 1 structure of the present application also includes a working platform 8 and at least two detection channels 9. The working platform 8 is fixed on the top surface 101 of the shielding body 10, and a middle opening 81 exposing the upper component 2 and at least two detection holes 82 surrounding the periphery of the middle opening 81 are provided through the middle of the working platform 8.

[0059] See also Figures 2 to 4 The detection channel 9 extends from the top surface 101 of the shielding body 10 to at least a part of the cavity wall of the pit 1, and the detection channel 9 is arranged around the circumference of the pit 1. Each detection channel 9 is formed with a detector entrance 911 on the top surface 101 of the shielding body 10, and the detector entrance 911 is connected one-to-one with the exploration hole 82 on the working platform 8, so that the detector is lowered into the corresponding detection channel 9 through the exploration hole 82 and the detector entrance 911 (not shown).

[0060] The reactor pit structure of the present application is provided with at least two detection channels 9 in the circumferential direction of the reactor pit 1. The upper end of each detection channel 9 penetrates the top surface 101 of the shielding body 10 and is formed with a detector entrance 911 which is connected one-to-one with the corresponding exploration holes 82, so that the detector can be lowered from the top surface 101 of the shielding body 10 to the corresponding detection channel 9 through the exploration holes 82 and the detector entrance 911, avoiding the upper component 2, thereby realizing the out-of-pit detection of the pressure vessel 5 inside the reactor pit 1 and avoiding the interference between the detection channel 9 and the upper supporting mechanism of the reactor pressure vessel 5, the primary shielding component 22 and the related auxiliary loads, facilitating the out-of-core neutron measurement operation and realizing the installation and maintenance of the out-of-core detector.

[0061] See also Figures 2 to 4 In some embodiments, each detection channel 9 includes a sixth section 91 and a seventh section 92 connected in sequence, wherein the sixth section 91 is arranged to extend in an arc shape from the top surface 101 of the shielding body 10 at the outer side of the upper component 2 and along the axial direction of the pile pit 1 to one side close to the upper cavity wall.

[0062] The seventh section 92 is connected to the sixth section 91, and the seventh section 92 is extended along the axial direction of the stack pit 1 toward the end away from the top surface 101 of the shielding body 10. The seventh section 92 penetrates the cavity wall of the stack pit 1 on the side facing the stack pit 1 and forms a detection window 921. The cross section of the detection window 921 perpendicular to the central axis 104 of the stack pit 1 is an outward-expanding bell-mouth structure.

[0063] In the pit structure provided in the present application, the length of the seventh section 92 of the detection channel 9 in the axial direction of the pit 1 is preferably greater than the length of the sixth section 91 in the axial direction of the pit 1, so that the lower end of the seventh section 92 away from the top surface 101 of the shielding body 10 can extend downward to the middle cavity wall or the lower cavity wall of the pit 1, so that the detection window 921 penetrating the pit cavity wall can have a sufficient field of view in the axial direction, so that the detector can see the core of the entire reactor pressure vessel 5 in the axial direction of the pit 1 through the detection window 921.

[0064] At the same time, in the pit structure provided by the present application, the cross section of the detection window 921 formed by the detection channel 9 penetrating the cavity wall of the pit is an outward-expanding trumpet-shaped structure, so that the two side walls of the detection window 921 in the circumferential direction of the pit 1 are in a corresponding outward expansion form, so that the detection window 921 penetrating the cavity wall of the pit can have a sufficient field of view in the circumference, so that the detector can see the core of the entire reactor pressure vessel 5 in the circumferential direction of the pit 1 through the detection window 921. Multiple detection channels 9 are arranged around the circumference of the pit 1, and the entire reactor pressure vessel 5 can be observed in the axial and circumferential directions of the pit 1 through at least two detectors, which meets the requirement that the sensitivity end of the detector is not blocked in the axial and circumferential directions of the pit 1 during the detection operation, and the detection result is more accurate.

[0065] In some embodiments, the working platform 8 of the pile pit 1 structure of the present application adopts a steel grating platform, whose overall size matches the size of the top surface 101 of the concrete shielding body 10, and is a structure with a square outside and a round inside, and the size of its circular middle opening 81 meets the size requirement of exposing the upper member 2. The steel grating platform itself is densely covered with hole structures, and the opening size of these hole structures is preferably set to be larger than the diameter of the detector entrance 911 formed by the detection channel 9 on the top surface 101 of the shielding body 10. In this way, there is no need to specially set the exploration hole 82 on the working platform 8, and the hole structure of the steel grating platform itself that is connected to the corresponding detector entrance 911 can be used as the exploration hole 82.

[0066] The above are only preferred implementation methods of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A pool-type reactor pit structure, characterized in that: include: A stack pit (1) is formed by being recessed inward from a top surface (101) of a shielding body (10) to accommodate a pressure vessel (5); An upper member (2) is fixedly mounted on the top surface (101) of the shielding body (10) and closes the pit opening (131) of the stack pit (1); a fluid space (6) is defined between the upper member (2), the cavity wall of the stack pit (1) and the pressure vessel (5); An air inlet channel (3) extending in a zigzag manner from the outside of the shielding body (10) to penetrate the lower cavity wall of the stack pit (1) so as to supply air into the fluid space (6); At least two exhaust passages (4) extending in a zigzag manner from the top surface (101) of the shielding body (10) to the upper cavity wall penetrating the stack pit (1) so as to exhaust air to the outside of the fluid space (6); All of the exhaust passages (4) are evenly arranged on one side of the central axis (104) of the stacking pit (1), and the air inlet passages (3) are arranged on the other side of the central axis (104) of the stacking pit (1).

2. The pool reactor pit structure according to claim 1, characterized in that: Each of the air inlet channels (3) comprises a first section (31), at least one second section (32), and a third section (33) which are connected in sequence, wherein: The first section (31) is horizontally extended along a first direction, and an end of the first section (31) away from the stack pit (1) penetrates the outer wall of the shielding body (10); The third section (33) is horizontally extended along the second direction, and one end of the third section (33) facing the stacking pit (1) penetrates the lower cavity wall; The first section (31) has a height in the axial direction of the stack pit (1) greater than that of the third section (33); the second section (32) connects the first section (31) and the third section (33); and the first direction is different from the second direction.

3. The pool reactor pit structure according to claim 2, characterized in that: The projection of the entire exhaust passage (4) on the top surface (101) of the shielding body (10) has a symmetry axis (105) extending radially along the stack pit (1), and the projection of the third section (33) on the top surface (101) of the shielding body (10) is located on the symmetry axis (105).

4. The pool-type reactor pit structure according to claim 1, characterized in that: Each of the exhaust passages (4) comprises a fourth section (41) and a fifth section (42) connected in sequence, wherein: The fourth section (41) is extended along the radial direction of the stack pit (1), and one end of the fourth section (41) facing the stack pit (1) penetrates the upper cavity wall; The fifth section (42) is extended along the axial direction of the stack pit (1), and one end of the fifth section (42) away from the stack pit (1) passes through the top surface (101) of the shielding body (10); the fifth section (42) is vertically connected to the fourth section (41).

5. The pool-type reactor pit structure according to any one of claims 1 to 4, characterized in that: The stack pit (1) comprises a main body section (11), a connecting section (12), and a pit mouth section (13) connected by coaxial lines; the inner diameter of the main body section (11) is larger than the inner diameter of the pit mouth section (13); the connecting section (12) connects the main body section (11) and the pit mouth section (13); the pit mouth section (13) forms a pit mouth (131) of the stack pit (1) on the top surface (101) of the shielding body (10); The upper cavity wall and the lower cavity wall are both located on the main body section (11); The upper component (2) comprises an upper supporting structure (21), wherein the upper supporting structure (21) at least partially presses against the periphery of the pit opening (131), and the pressure vessel (5) and / or the thermal insulation layer arranged outside the pressure vessel (5) at least partially presses against the upper supporting structure (21).

6. The pool-type reactor pit structure according to claim 5, characterized in that: The upper component (2) further comprises a primary shield (22), wherein the primary shield (22) covers the upper support structure (21), the pressure vessel (5) and / or the thermal insulation layer and closes the stack pit (1).

7. The pool reactor pit structure according to any one of claims 1 to 4, characterized in that: The stack pit (1) structure also includes: A coolant injection channel (7) extends in a zigzag manner from the lower outer portion of the shielding body (10) to the lower cavity wall penetrating the stack pit (1), so as to inject coolant into the fluid space (6) in an emergency, and the injected coolant is poured onto the top surface (101) of the shielding body (10) through the exhaust channel (4).

8. The pool-type reactor pit structure according to claim 7, characterized in that: The inner diameters of the coolant injection channel (7) and the exhaust channel (4) are both smaller than the inner diameter of the air inlet channel (3).

9. The pool-type reactor pit structure according to any one of claims 1 to 4, characterized in that: The stack pit (1) structure also includes: A working platform (8) is fixed on the top surface (101) of the shielding body (10), and is provided with a central opening (81) through which the upper member (2) is exposed, and at least two exploration holes (82) surrounding the periphery of the central opening (81); At least two detection channels (9) are bent and extended from the top surface (101) of the shielding body (10) to the cavity wall penetrating the pile pit (1), and are arranged around the circumference of the pile pit (1); the detection channel (9) is formed with a detector entrance (911) on the top surface (101) of the shielding body (10), and the detector entrance (911) is connected to the exploration hole (82) one by one, so that the detector can be lowered into the detection channel (9) through the exploration hole (82) and the detector entrance (911).

10. The pool-type reactor pit structure according to claim 9, characterized in that: Each of the detection channels (9) comprises a sixth section (91) and a seventh section (92) connected in sequence, wherein: The sixth section (91) is arranged to extend in an arc shape from the top surface (101) of the shielding body (10) at the outer side of the upper component (2) and along the axial direction of the stack pit (1) toward a side close to the upper cavity wall; The seventh section (92) is connected to the sixth section (91), and the seventh section (92) is extended along the axial direction of the stack pit (1) toward one end of the top surface (101) away from the shielding body (10); the seventh section (92) penetrates the cavity wall of the stack pit (1) toward one side of the stack pit (1) and forms a detection window (921); the cross section of the detection window (921) perpendicular to the central axis (104) is an outward-expanding trumpet-shaped structure.

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