Pool type reactor pit structure

Abstract

The application provides a pool type reactor pit structure, relates to the technical field of nuclear reactors, and comprises a pit, an upper component, an air inlet channel, at least two air outlet channels, and a self-shielding body. The pit is recessed inward from the top surface of the self-shielding body to accommodate a pressure vessel. The upper component is fixed to the top surface of the self-shielding body and closes the pit opening. The fluid space is defined among the upper component, the cavity wall of the pit and the pressure vessel. The air inlet channel extends outward from the upper part of the self-shielding body to the lower cavity wall of the pit. The air outlet channel extends outward from the top surface of the self-shielding body to the upper cavity wall of the pit. All the air outlet channels are uniformly arranged on one side of the central axis of the pit, and the air inlet channel is arranged on the other side of the central axis of the pit. The application avoids direct penetration of the self-shielding body, can stop the leakage of radioactive substances in the reactor, realizes 360-degree envelope ventilation of the reactor pressure vessel, can continuously cool the reactor pressure vessel, and has better heat dissipation effect.

Description

TECHNICAL FIELD

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

[0002] The pool-type reactor pit structure is used for installing a reactor pressure vessel, and is formed by recessing a top surface of a shielding body in an axial straight-through manner. An upper component is used to close an opening of the pit. A cavity wall of the pit, the reactor pressure vessel and the upper component define a fluid space.

[0003] The pit structure includes an air inlet channel and an air outlet channel for ventilation of the fluid space and the outside of the pit, so as to cool the reactor pressure vessel. In the existing pit structure, the air inlet channel and the air outlet channel directly penetrate the entire biological shielding layer outside the pit. The air inlet channel and the air outlet channel are designed in a straight-through pipeline structure. Radioactive substances in the pit are prone to leakage to the outside of the pit through the air inlet channel and the air outlet channel, and there is a safety risk of neutron leakage.

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

[0005] The present application provides a pool-type reactor pit structure, which is used to solve the technical problems of unreasonable structure design of the existing pool-type reactor pit structure, easy leakage of radioactive substances in the pit through the air inlet channel and the air outlet channel, and poor cooling effect on the pressure vessel. The pool-type reactor pit structure provided by the present application can stop the leakage of radioactive substances in the reactor through multiple inflection points on the ventilation path, and can form 360° envelope ventilation for the reactor pressure vessel, thereby achieving a better cooling effect on the pressure vessel.

[0006] In some embodiments of the present application, a pool-type reactor pit structure is provided, which includes: a pit recessed inward from a top surface of a shielding body to accommodate a pressure vessel; an upper component fixed to the top surface of the shielding body and closing an opening of the pit, the upper component, a cavity wall of the pit and the pressure vessel defining a fluid space; an air inlet channel extending from the outside of the shielding body to the lower cavity wall of the pit in a zigzag manner to supply air to the fluid space; and at least two air outlet channels extending from the top surface of the shielding body to the upper cavity wall of the pit in a zigzag manner to exhaust air outside the fluid space. All the air outlet channels are uniformly arranged on one side of the central axis of the pit, and the air inlet channel is arranged on the other side of the central axis of the pit.

[0007] In some embodiments, each of the air inlet channels comprises a first section, at least a second section, and a third section connected in sequence, wherein: the first section is arranged to extend horizontally along a first direction, and one end of the first section away from the pit penetrates through the outer wall of the shield; the third section is arranged to extend horizontally along a second direction, and one end of the third section toward the pit penetrates through the lower cavity wall; the height of the first section in the axial direction of the pit is greater than that of the third section, and 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, the projections of all the air outlet channels on the top surface of the shield have a symmetry axis extending along the radial direction of the pit, and the projection of the third section on the top surface of the shield is on the symmetry axis.

[0009] In some embodiments, each of the air outlet channels comprises a fourth section and a fifth section connected in sequence, wherein: the fourth section is arranged to extend along the radial direction of the pit, and one end of the fourth section toward the pit penetrates through the upper cavity wall; the fifth section is arranged to extend along the axial direction of the pit, and one end of the fifth section away from the pit penetrates through the top surface of the shield; and the fifth section is connected perpendicularly to the fourth section.

[0010] In some embodiments, the pit comprises a main body section, a connecting section, and a pit mouth section connected coaxially, the inner diameter of the main body section is greater than that of the pit mouth section, the connecting section connects the main body section and the pit mouth section, and the pit mouth section forms a pit mouth of the pit on the top surface of the shield; the upper cavity wall and the lower cavity wall are both located on the main body section; the upper member comprises an upper supporting structure, which is at least partially pressed against the periphery of the pit mouth, and the pressure vessel and / or the heat insulation layer provided outside the pressure vessel is at least partially pressed against the upper supporting structure.

[0011] In some embodiments, the upper member further comprises a primary shield, which covers the upper supporting structure, the pressure vessel, and / or the heat insulation layer and encloses the pit.

[0012] In some embodiments, the pit structure further comprises a cooling liquid injection channel extending from the lower outer curve of the shield to penetrate through the lower cavity wall of the pit, so as to inject cooling liquid into the fluid space in an emergency, and the injected cooling liquid is poured onto the top surface of the shield through the air outlet channel.

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

[0014] In some embodiments, the pit structure further comprises: a work platform fixed on the top surface of the shielding body and provided with a middle opening exposing the upper member and at least two probe holes surrounding the periphery of the middle opening;

[0015] At least two detection channels extend outward from the top surface of the shielding body to the cavity wall of the pit and are arranged around the circumference of the pit; the detection channels are formed with detector entrances on the top surface of the shielding body, which one-to-one communicate with the probe holes to lower the detector into the detection channel through the probe holes and the detector entrances.

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

[0017] The sixth section extends arcuately from the top surface of the shielding body at a position outside the upper member to the side of the pit close to the upper cavity wall;

[0018] The seventh section communicates with the sixth section and extends from the top surface of the shielding body to the end away from the shielding body in the axial direction of the pit; the seventh section penetrates the cavity wall of the pit on one side of the pit and is formed with a detection window, and the cross section of the detection window perpendicular to the central axis is in the shape of an outwardly expanding horn.

[0019] The pit structure of the pool type reactor provided by the present application comprises a pit, an upper member, an air inlet channel, and at least two air outlet channels. The reactor pressure vessel is installed in the pit, the upper member is fixed to the top surface of the shielding body and closes the pit opening, and the upper member, the cavity wall of the pit, and the pressure vessel define a fluid space. The air inlet channel extends outward from the upper part of the shielding body to the lower cavity wall of the pit, and is used for supplying air to the fluid space. The at least two air outlet channels extend outward from the top surface of the shielding body to the upper cavity wall of the pit, and are used for discharging air outside the fluid space.

[0020] The air inlet channel and the air outlet channel extend zigzagly and jointly form a labyrinth ventilation path for the gas medium in and out of the fluid space in the pit structure. Compared with the straight path extending hole structure on the existing reactor shielding body, the improved ventilation path of the pit structure of the present application avoids direct penetration of the shielding body, meets the safety requirement of the biological shielding layer of the reactor wall, and can stop the leakage of radioactive substances in the reactor through the multiple inflection points on the ventilation path, thereby solving the problem of leakage of radioactive substances in the pit caused by the direct penetration of the air inlet channel through the entire biological shielding layer.

[0021] In addition, all the air exhaust channels in the stack pit structure of the application are uniformly arranged on one side of the central axis of the stack pit, and the air inlet channels are arranged on the other side of the central axis of the stack pit, so that the external airflow can enter the lower cavity wall of the stack pit on the side close to the bottom of the stack pit via the air inlet channels, can be distributed to the circumferential two sides of the inner cavity of the stack pit around the pressure vessel, and finally is discharged upward from the plurality of air exhaust channels on the upper cavity wall of the stack pit, thereby realizing 360° envelope ventilation of the reactor pressure vessel, continuously cooling the reactor pressure vessel, and achieving better heat dissipation effect. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained from these drawings without creative labor, wherein:

[0023] Figure 1 It is a schematic view of the overall structure of a specific embodiment of the stack pit structure of the application;

[0024] Figure 2 It is a schematic view of the structure of the stack pit structure of the application after hiding the upper member and the operation platform; Figure 1

[0025] Figure 3 It is a schematic view of the structure of the stack pit structure of the application after hiding the upper member and the operation platform;

[0026] Figure 4 It is a schematic view of the structure of the stack pit structure of the application after hiding the upper member and the operation platform. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the application, not all the embodiments. According to the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application. In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various embodiments. At the same time, the steps or actions in the method description can also be sequentially adjusted or adjusted in a manner that is obvious to those skilled in the art. Therefore, the order in the specification and the drawings is only for clear description of an embodiment, and does not mean that it is the necessary order, unless otherwise stated that a certain order must be followed.

[0028] Please refer to Figures 1 to 3 ​In some embodiments of the present application, a pool reactor pit structure is provided in a reactor containment 100. The pit structure comprises a pit 1, an upper member 2, an air inlet passage 3, and at least two air outlet passages 4. The pit 1 is recessed inward from a top surface 101 of a shield 10 to accommodate a pressure vessel 5. The upper member 2 is fixedly connected to the top surface 101 of the shield 10 and closes an opening 131 of the pit 1. A fluid space 6 is defined among the upper member 2, the cavity wall of the pit 1, and the pressure vessel 5. The shield 10 is a bottom member of the reactor containment 100, which forms the pit 1 and supports the equipment inside the pit 1, and prevents radioactive substances in the pit 1 from leaking to the outside. In the present application, the shield 10 is exemplified by a concrete shield.

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

[0030] The air inlet passage 3 extends from the outside of the shield 10 to the lower cavity wall near the bottom of the pit 1 to supply air to the fluid space 6. The air outlet passage 4 extends from the top surface 101 of the shield 10 to the upper cavity wall near the opening 131 of the pit 1 to exhaust air from the fluid space 6. All the air outlet passages 4 are uniformly arranged on one side of the central axis 104 of the pit 1, and the air inlet passage 3 is arranged on the other side of the central axis 104 of the pit 1. In the present embodiment, all the air outlet passages 4 are uniformly arranged on the left side of the central axis 104 of the pit 1, and the air inlet passage 3 is arranged on the right side of the central axis 104 of the pit 1.

[0031] In the present application, the shield 10 is exemplified by a cubic concrete shield 10. The pit 1 is preferably recessed inward from the middle of the top surface 101 of the shield 10 to the inside of the shield 10, so that the cavity wall of the pit 1 and the outer wall of the shield 10 form a concrete biological shielding layer outside the pit 1. 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 needs to meet the safety shielding requirements. The ventilation paths of the air inlet passage 3 and the air outlet passage 4 are in the side biological shielding layer.

[0032] The pool reactor pit structure provided by the application, the zigzag extending air inlet channel 3 and the air outlet channel 4 jointly constitute a labyrinth ventilation path for the gas medium in the fluid space 6 in the pit 1 structure, and a plurality of inflection points are formed on the air inlet channel 3 and the air outlet channel 4. Compared with the straight path extending hole structure on the existing reactor shield 10, the improved ventilation path of the pit 1 structure of the application avoids direct penetration of the side biological shielding layer of the shield 10, meets the safety requirement of the reactor wall biological shielding layer perforation, and can stop the leakage of radioactive substances in the reactor through the plurality of inflection points on the ventilation path, solves the problem of leakage of radioactive substances in the pit 1 caused by the direct penetration of the pit 1 air inlet channel 3 through the entire biological shielding layer, and is safer.

[0033] In addition, all the air outlet channels 4 in the pit 1 structure of the application are uniformly arranged on one side of the central axis 104 of the pit 1, and the air inlet channel 3 is arranged on the other side of the central axis 104 of the pit 1, so that the external airflow can enter the lower cavity wall of the pit 1 on the side close to the bottom of the pit 1 via the air inlet channel 3, be divided into two parts around the pressure vessel 5, and finally be discharged upward from the plurality of air outlet channels 4 on the upper cavity wall of the pit 1, realizing 360° envelope ventilation of the reactor pressure vessel 5, continuously cooling the reactor pressure vessel 5, and better ventilation and heat dissipation effect.

[0034] Please refer to Figures 2 to 3 In some embodiments, each air inlet channel 3 comprises a first section 31, at least one second section 32 and a third section 33 connected in sequence, wherein the first section 31 is arranged to extend horizontally along a first direction, and the first section 31 penetrates the outer wall of the shield 10 away from the outer end of the pit 1 and forms an outer air inlet 311, which is connected with the air blowing device upstream of the pit cooling system for the low-temperature airflow to enter the air inlet channel 3. The third section 33 is arranged to extend horizontally along a second direction, and the third section 33 penetrates the lower cavity wall of the pit 1 towards the inner end of the pit 1 and forms an inner air inlet 331 close to the bottom of the pit 1, which is communicated with the fluid space 6 for the low-temperature airflow to enter the fluid space 6 from the position on the other side of the central axis 104 of the pit 1 close to the bottom of the pit 1. 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, and the second section 32 is communicated with 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 arranged, 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 above the third section 33 in the vertical direction, and the first section 31 is between the outer end 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 three-dimensional space in the side shielding layer. The air inlet channel 3 can form a three-dimensional space in the side shielding layer.

[0036] In the embodiment, the second section 32 is arranged as a separate section, which can shorten the total length of the ventilation path of the air inlet channel 3, reduce the difficulty of the perforation operation of the shielding body 10, and facilitate the rapid air supply to the fluid space 6. When the first section 31 is on the same vertical line between the outer end inside the side shielding layer and the inner end of the third section 33 inside the side shielding layer, the second section 32 is arranged 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 forms a zigzag ventilation path in a three-dimensional space. When the radioactive material inside the pit 1 enters the air inlet channel 3 through the inner air inlet 331, it will be stopped at least twice at the inflection points of the connection between the third section 33 and the second section 32 and the connection between the second section 32 and the first section 31, significantly reducing the risk of leakage of radioactive material outside through the air inlet channel 3.

[0037] In other embodiments, the second section 32 can also be arranged as multiple sections extending in different directions and connected, which can increase the number of inflection points in the air inlet channel 3 and improve the stopping effect of the radioactive material inside the pit 1, but at the same time, it also increases the total length of the ventilation path and the difficulty of the perforation operation of the shielding body 10. In actual manufacture, the number of arrangements of the second section 32 and the extension direction of each second section 32 can be adjusted according to actual needs.

[0038] Please refer to Figure 3 In some embodiments, the projection of all the air outlet channels 4 on the top surface 101 of the shielding body 10 has a symmetry axis 105 extending in the radial direction of the 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 on the symmetry axis 105. In this way, the third section 33 penetrates the inner air inlet 331 formed by the lower cavity wall of the pit 1, and the airflow entering the fluid space 6 through the inner air inlet 331 can be uniformly distributed to both sides of the inner cavity of the pit 1 and then discharged through the air outlet channels 4, respectively, which ensures uniform heat dissipation of the reactor pressure vessel 5 and further improves the heat dissipation effect.

[0039] Further, the first section 31 of the air inlet channel 3 is preferably arranged perpendicularly 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 biological shielding layer, wherein the vertical distance of the first section 31 from the top surface of the side biological shielding layer (i.e., the top surface 101 of the shielding body 10, which will not be described below) cannot be less than 1.5 m, and is preferably between 1.5 m and 3 m; the vertical distance of the second section 32 from 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 described below) cannot be less than 1.5 m, and is preferably between 1.5 m and 3 m; and the vertical distance of the third section 33 from the bottom surface of the bottom biological shielding layer (i.e., the bottom wall surface of the shielding body 10, which will not be described below) cannot be less than 1.5 m, and is preferably between 1.5 m and 3 m.

[0042] Please refer to Figures 1 to 2 In some embodiments, each air outlet channel 4 includes a fourth section 41 and a fifth section 42 connected in sequence, wherein the fourth section 41 is arranged to extend in the radial direction of the heap pit 1, and the fourth section 41 penetrates the upper cavity wall of the heap pit 1 towards the inner end of the heap pit 1 and forms an inner air outlet 411, which communicates with the fluid space 6, for the hot gas flow heated by heat exchange in the heap pit 1 to enter the air outlet channel 4 from one side of the central axis 104 of the heap pit 1, close to the pit opening 131 of the heap pit 1. The fifth section 42 is arranged to extend in the axial direction of the heap pit 1, i.e., the vertical direction, and the fifth section 42 penetrates the top surface 101 of the shielding body 10 upwards away from the outer end of the heap pit 1 and forms an outer air outlet 421, which is connected to the equipment related to heat recovery and purification treatment downstream of the heap cooling system, for recovering and treating the discharged hot gas flow. The fifth section 42 is connected perpendicularly to the fourth section 41.

[0043] The exhaust passage 4 is provided with the fourth section 41 and the fifth section 42 which are vertically connected, so that the total length of the ventilation path of the exhaust passage 4 is shortened, the difficulty of the perforation operation of the shielding body 10 is reduced, and the hot gas flow in the fluid space 6 after heat exchange and temperature rise can be quickly discharged. When the fifth section 42 is vertically connected to the fourth section 41, the total length of the ventilation path of the exhaust passage 4 is the shortest, and the ventilation path of the exhaust passage 4 forms a zigzag extension approximately in the shape of L in the vertical plane. When the radioactive material in the pit 1 enters the corresponding exhaust passage 4 through the inner exhaust port 411, it is at least stopped by the inflection point at the connection between the fourth section 41 and the fifth section 42, thereby significantly reducing the risk of leakage of radioactive material to the outside through the exhaust passage 4.

[0044] Please refer to Figure 2 In some embodiments, the pit 1 comprises, from the bottom to the pit opening 131, the main body section 11, the connecting section 12, and the pit opening section 13 which are coaxially connected, the inner diameter of the main body section 11 is larger than that of the pit opening section 13, the connecting section 12 connects the main body section 11 and the pit opening section 13, and the pit opening section 13 forms the pit opening 131 of the pit 1 on the top surface 101 of the shielding body 10. The upper cavity wall and the lower cavity wall of the pit 1 are both located on the main body section 11, so that the length of the inner wall surface of the pit opening section 13 in the axial direction of the pit 1 is significantly smaller than that of the inner wall surface of the main body section 11. Since the inner diameter of the main body section 11 is larger than that of the pit opening 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 opening section 13 and forms a downwardly inclined slope, so that a similar cut-angle bracket structure is formed at the pit opening 131 of the pit 1.

[0045] Please refer to Figure 1 The upper member 2 comprises an upper supporting structure 21 which is at least partially pressed against the periphery of the pit opening 131 of the pit 1, and the pressure vessel 5 and / or the heat preservation layer 51 arranged outside the pressure vessel 5 is at least partially pressed against the upper supporting structure 21. The outer part of the reactor pressure vessel 5 is generally provided with a heat preservation layer 51 for heat preservation, and the main body of the pressure vessel 5 is accommodated in the inner cavity of the heat preservation layer 51. After installation, the heat preservation layer 51, the cavity wall of the pit 1, and the upper member 2 can define the fluid space 6. During installation, the mounting flange at the top of the pressure vessel 5 is seated on the upper supporting structure 21, and the two are locked and fixed by fasteners. Preferably, the top outer periphery of the heat preservation layer 51 is at least partially fixed and connected with the pressure vessel 5 on the upper supporting structure 21, so as to limit and fix the pressure vessel 5 and the heat preservation layer 51 together in the pit 1 by the upper supporting structure 21.

[0046] The connecting section 12 and the pit opening section 13 of the pit 1 in combination with the concrete shield 10 bear the upper component 2, the pressure vessel 5, the thermal insulation layer 51 and related loads. Compared with the straight-through inner cavity structure of the pit in the prior art, the inner cavity diameter of the main body section 11 of the pit 1 is greater than the inner cavity diameter of the pit opening section 13. When the pressure vessel 5 and the thermal insulation layer 51 are hoisted and installed into the pit 1 through the pit opening 131, the distance between the inner wall surface of the main body section 11 and the outer thermal insulation layer 51 of the pressure vessel 5 is significantly increased, thereby increasing the volume of the fluid space 6 defined between the inner wall surface of the main body section 11 and the outer thermal insulation layer 51 of the pressure vessel 5, further increasing the amount of fluid medium filled in the fluid space 6, improving the heat exchange efficiency between the fluid medium and the pressure vessel 5, and further improving the ventilation and heat dissipation effect of the pressure vessel 5.

[0047] In some embodiments, after the installation of the pressure vessel 5 and the thermal insulation layer 51, the vertical distance between the inner wall surface of the pit opening section 13 and the outer thermal insulation layer 51 of the pressure vessel 5 is less than 10 cm, and is preferably 5-7 cm; and the vertical distance between the inner wall surface of the main body section 11 and the outer thermal insulation layer 51 of the pressure vessel 5 is greater than 10 cm, and is preferably 20-40 cm, so that the volume of the fluid space 6 can meet the ventilation and heat dissipation requirements of the pressure vessel 5 and the water injection volume requirements of the pit 1 in case of an accident.

[0048] The height of the inner wall surface of the pit opening section 13 in the axial direction of the pit 1 and the height of the inner wall surface of the connecting section 12 in the axial direction of the pit 1 are determined according to the total weight of the pool-type reactor upper component 2, the pressure vessel 5 and the thermal insulation layer 51 and the weight of various related loads that can be borne by the cut-angle bracket structure at the pit opening 131, and can be calculated by stress analysis of the pit opening section 13 and the connecting section 12.

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

[0050] Please refer to Figure 1 In some embodiments, the upper component 2 further comprises a primary shield 22, which covers the upper support structure 21, the pressure vessel 5 and the thermal insulation layer 51 and seals the pit 1. The primary shield 22 seals the pit 1 from the outside, preventing the radioactive substances in the pit 1 from directly leaking into the reactor containment 100 through the pit opening 131.

[0051] Please refer to Figures 1 to 3In some embodiments, the reactor pit 1 structure further comprises a cooling liquid injection channel 7, which extends 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 the bottom surface thereof in a tortuous manner, so that in the event of an emergency such as a safety accident of the reactor, cooling liquid can be injected into the fluid space 6 through the cooling liquid injection channel 7, and the injected cooling liquid can flow onto the top surface 101 of the shielding body 10 through the exhaust channel 4, ensuring that the amount of injected cooling liquid can meet the requirement of unattended and intervention-free for at least three days, so that the heat in the reactor pit 1 can be timely removed by the cooling liquid, preventing the high-temperature molten material in the pressure vessel 5 from melting through the lower head of the vessel and entering the reactor pit 1.

[0052] Referring to 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 "lift" the top of the reactor pressure vessel 5 out of the pit opening 131 of the reactor pit 1, and form a certain gap between the top surface 101 of the concrete shielding body 10 and the mounting flange end surface of the top of the pressure vessel 5, which can further increase the volume of the fluid space 6 to some extent, and ensure that the fluid space 6 can be filled with sufficient amount of cold gas flow, cooling liquid and other fluid media.

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

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

[0055] Referring to Figures 1 to 3 In a specific embodiment, the reactor pit 1 structure is provided with a cooling liquid injection channel 7, which extends in a tortuous manner on a horizontal plane near the bottom surface of the reactor pit 1 and is arranged on the right side of the central axis 104 of the reactor pit 1. The cooling liquid injection channel 7 comprises 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. The first injection section 71 extends from the lower outer portion of the concrete shielding body 10 near the bottom of the reactor pit 1 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 reactor pit 1 penetrates the lower outer wall of the shielding body 10 and forms an outer liquid inlet 711, which is connected with the water injection tank and other related equipment upstream of the reactor pit cooling system, for the cooling liquid to enter the cooling liquid injection channel 7. The second injection section 72 extends in the radial direction of the reactor pit 1, and the inner end of the second injection section 72 toward the reactor pit 1 penetrates the lower cavity wall of the reactor pit 1 near the bottom surface thereof and forms an inner liquid inlet 721, which communicates with the fluid space 6, for the cooling liquid to enter the fluid space 6 from the right side of the central axis 104 of the reactor pit 1 near the bottom of the reactor pit 1.

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

[0057] The first injection section 71 and the second injection section 72 of the cooling liquid injection channel 7 are connected at an angle, so that the radioactive material entering through the inner liquid inlet 721 is at least 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 cooling liquid injection channel 7.

[0058] Referring to Figure 1 In some embodiments, the pit 1 structure of the present application further includes a work platform 8 and at least two detection channels 9. The work platform 8 is fixed to the top surface 101 of the shielding body 10, and a central opening 81 exposing the middle part of the upper component 2 and at least two detection holes 82 surrounding the periphery of the central opening 81 are provided in the middle part of the work platform 8.

[0059] Referring to Figures 2 to 4 The detection channel 9 extends from the top surface 101 of the shielding body 10 to at least part of the cavity wall of the pit 1 in a zigzag manner, and the detection channel 9 is arranged around the circumference of the pit 1. Each detection channel 9 forms a detector inlet 911 on the top surface 101 of the shielding body 10, which communicates one-to-one with the detection hole 82 on the work platform 8, so that the detector (not shown) can be lowered into the corresponding detection channel 9 through the detection hole 82 and the detector inlet 911.

[0060] The pit structure of the present application is provided with at least two detection channels 9 around the circumference of the pit 1. The upper end of each detection channel 9 penetrates the top surface 101 of the shielding body 10 and forms a detector inlet 911 that communicates one-to-one with the corresponding detection hole 82, so that the detector can be lowered from the outside of the top surface 101 of the shielding body 10, avoiding the upper component 2, into the corresponding detection channel 9 through the detection hole 82 and the detector inlet 911, realizing the out-of-pit detection of the internal pressure vessel 5 of the pit 1, avoiding the interference between the detection channel 9 and the upper support mechanism of the reactor pressure vessel 5, the primary shielding 22 and related auxiliary loads, facilitating the out-of-pit neutron measurement operation, and realizing the installation and maintenance of the out-of-pit detector.

[0061] Referring to 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 along the axial direction of the pit 1 from the top surface 101 of the shielding body 10 at a position outside the upper component 2 to the side of the upper cavity wall.

[0062] The seventh section 92 is in communication with the sixth section 91 and extends along the axial direction of the reactor pit 1 away from the top surface 101 of the shielding body 10. The seventh section 92 penetrates the cavity wall of the reactor pit 1 towards one side of the reactor pit 1 and is formed with a detection window 921 which has a cross section perpendicular to the central axis 104 of the reactor pit 1 in the shape of an outwardly expanding trumpet.

[0063] The length of the seventh section 92 of the detection channel 9 in the axial direction of the reactor pit 1 is preferably greater than the length of the sixth section 91 in the axial direction of the reactor 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 or lower cavity wall of the reactor pit 1, so that the detection window 921 penetrating the cavity wall of the reactor pit 1 can have a sufficient field of view in the axial direction, so that the detector can see the entire core of the reactor pressure vessel 5 in the axial direction of the reactor pit 1 through the detection window 921.

[0064] Meanwhile, the cross section of the detection window 921 formed by the detection channel 9 penetrating the cavity wall of the reactor pit 1 is in the shape of an outwardly expanding trumpet, so that the two side walls of the detection window 921 in the circumferential direction of the reactor pit 1 are in the form of corresponding outward expansion, so that the detection window 921 penetrating the cavity wall of the reactor pit 1 can have a sufficient field of view in the circumferential direction, so that the detector can see the entire core of the reactor pressure vessel 5 in the circumferential direction of the reactor pit 1 through the detection window 921. A plurality of detection channels 9 are arranged around the circumferential direction of the reactor pit 1, and the entire reactor pressure vessel 5 can be observed in the axial and circumferential directions of the reactor pit 1 by at least two detectors, meeting the requirement that the sensitive end of the detector is not blocked in the axial and circumferential directions of the reactor pit 1 during the detection operation, and the detection result is more accurate.

[0065] In some embodiments, the work platform 8 of the reactor pit 1 structure of the present application adopts a steel grating platform, the overall size of which matches the size of the top surface 101 of the concrete shielding body 10, and is in the structure of an outer square and an inner circle, and the size of the circular middle opening 81 meets the size requirement of exposing the upper component 2. The steel grating platform itself is densely provided with hole structures, and the opening size of these hole structures is preferably greater than the diameter of the detector inlet 911 formed by the detection channel 9 on the top surface 101 of the shielding body 10. In this way, it is not necessary to specially provide a detection hole 82 on the work platform 8, and the hole structure of the steel grating platform itself, which is in communication with the corresponding detector inlet 911, can be used as the detection hole 82.

[0066] The above is only the preferred embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent flow transformation using the content of the specification and drawings, or direct or indirect application 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 by, The application relates to a heat exchanger comprising: a pit (1) recessed inward from the top surface (101) of a shielding body (10) to accommodate a pressure container (5); an upper member (2) fixed to the top surface (101) of the shielding body (10) and closing the pit opening (131) of the pit (1), the upper member (2), the cavity wall of the pit (1) and the pressure container (5) defining a fluid space (6) therebetween; an air inlet channel (3) extending from outside the shielding body (10) to the lower cavity wall of the pit (1) to supply air to the fluid space (6); at least two air outlet channels (4) extending from outside the top surface (101) of the shielding body (10) to the upper cavity wall of the pit (1) to exhaust air from the fluid space (6); all the air outlet channels (4) are arranged uniformly on one side of the central axis (104) of the pit (1), and the air inlet channel (3) is arranged on the other side of the central axis (104) of the pit (1); each air inlet channel (3) comprises a first section (31), at least one second section (32) and a third section (33) connected in sequence, wherein: the first section (31) extends horizontally along a first direction, and one end of the first section (31) away from the pit (1) penetrates the outer wall of the shielding body (10); the third section (33) extends horizontally along a second direction, and one end of the third section (33) toward the pit (1) penetrates the lower cavity wall; the height of the first section (31) in the axial direction of the pit (1) is 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; each air outlet channel (4) comprises a fourth section (41) and a fifth section (42) connected in sequence, wherein: the fourth section (41) extends along the radial direction of the pit (1), and one end of the fourth section (41) toward the pit (1) penetrates the upper cavity wall; the fifth section (42) extends along the axial direction of the pit (1), and one end of the fifth section (42) away from the pit (1) penetrates the top surface (101) of the shielding body (10); the fifth section (42) is connected perpendicularly to the fourth section (41).

2. The pool-type reactor pit structure according to claim 1, characterized by The projection of all the air outlet channels (4) on the top surface (101) of the shielding body (10) has a symmetry axis (105) extending along the radial direction of the pit (1), and the projection of the third section (33) on the top surface (101) of the shielding body (10) is on the symmetry axis (105).

3. The pool-type reactor pit structure according to claim 1 or 2, characterized by The stack pit (1) comprises a main body section (11), a connecting section (12), and a pit mouth section (13) connected coaxially, the inner diameter of the main body section (11) is larger than that of the pit mouth section (13), the connecting section (12) connects the main body section (11) and the pit mouth section (13), and the pit mouth section (13) forms a pit mouth (131) of the stack pit (1) on a 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) which is at least partially pressed against the periphery of the pit mouth (131), and the pressure container (5) and / or a heat preservation layer provided outside the pressure container (5) is at least partially pressed against the upper supporting structure (21).

4. The pool-type reactor pit structure according to claim 3, characterized by The upper component (2) further comprises a primary shielding member (22) which covers the upper supporting structure (21), the pressure container (5), and / or the heat preservation layer and seals the stack pit (1).

5. The pool-type reactor pit structure according to claim 1 or 2, characterized by The stack pit (1) structure further comprises: A cooling liquid injection channel (7) which extends from the lower outer curve of the shielding body (10) to the lower cavity wall of the stack pit (1) and injects cooling liquid into the fluid space (6) in an emergency, and the injected cooling liquid is poured onto the top surface (101) of the shielding body (10) through the exhaust channel (4).

6. The pool-type reactor pit structure according to claim 5, characterized by The inner diameters of the cooling liquid injection channel (7) and the exhaust channel (4) are both smaller than that of the air inlet channel (3).

7. The pool-type reactor pit structure according to claim 1 or 2, characterized by The stack pit (1) structure further comprises: A work platform (8) which is fixed on the top surface (101) of the shielding body (10) and is provided with a middle opening (81) exposing the upper component (2) and at least two detection holes (82) surrounding the periphery of the middle opening (81); At least two detection channels (9) which extend from the outer curve of the top surface (101) of the shielding body (10) to the cavity wall of the stack pit (1) and are arranged circumferentially around the stack pit (1); the detection channels (9) are formed with detector inlets (911) on the top surface (101) of the shielding body (10), and the detector inlets (911) are in one-to-one communication with the detection holes (82) to lower a detector into the detection channel (9) through the detection holes (82) and the detector inlets (911).

8. The pool-type reactor pit structure according to claim 7, characterized by Each of the detection channels (9) comprises a sixth section (91) and a seventh section (92) connected in sequence, wherein: The sixth section (91) extends from the top surface (101) of the shielding body (10) at a position outside the upper component (2) to the side of the upper cavity wall in the axial direction of the stack pit (1). The seventh section (92) is communicated with the sixth section (91), and the seventh section (92) is arranged to extend to an end away from the top surface (101) of the shielding body (10) along the axial direction of the pit (1); the seventh section (92) penetrates the cavity wall of the pit (1) towards one side of the pit (1) and is formed with a detection window (921), and the cross section of the detection window (921) perpendicular to the central axis (104) is in the shape of an outwardly expanding horn.

Images