Reactor internal and pressure vessel system

Abstract

A reactor internal and a pressure vessel system. The internal comprises an upper member (1), a lower member (2), a plurality of positioning assemblies (3), and a plurality of cushioning members (4). The plurality of positioning assemblies (3) centrally connect the upper member (1) and the lower member (2). The lower member (2) is constrained to a support step (101) at a lower end of a pressure vessel (100), and the plurality of cushioning members (4) are distributed at intervals in the circumferential direction of the lower member (2) and are arranged between the lower member (2) and the support step (101). The upper member (1) and the lower member (2) of the internal are centrally connected by means of the positioning assemblies (3), so that the use of a large number of fasteners is reduced and the risk of the fasteners becoming fatigued and falling off is reduced. By means of arranging the cushioning members (4) between the bottom of the internal and the support step (101) at the lower end of the pressure vessel (100), core drop supporting and drop cushioning functions are implemented, and, by means of eliminating a secondary support structure below the internal, problems caused by the secondary support structure are avoided.

Description

Reactor internals and pressure vessel systems Technical Field

[0001] The present invention relates to the technical field of nuclear power reactors, and in particular to a reactor internal component and a pressure vessel system. Background Art

[0002] Reactor internal structures are referred to as "core internals." Installed within the pressure vessel chamber, these components provide support, compression, and positioning for the fuel assembly and its associated components; protect and guide the control rod assembly; form internal coolant flow paths with the reactor pressure vessel, effectively distributing the flow rate before the core inlet; and provide guidance, protection, support, and positioning for core measuring instruments and irradiation sample monitoring tubes. Neutron flux measuring instruments are introduced into the core through instrument guides at the bottom of the pressure vessel to measure core reactivity. Water level and stability measuring instruments are introduced into the core through the pressure vessel top cover and the in-core instrument column to measure the water level and temperature at corresponding locations within the core.

[0003] In existing technology, core neutron flux measurement instruments are introduced from the bottom of the pressure vessel, which places high demands on the sealing performance of the pressure vessel bottom and poses the risk of leakage of high-level radioactive materials from the bottom. The core neutron flux measurement instrument channel structure is complex in the lower chamber of the pressure vessel, increasing fluid vortex in the lower chamber and detrimental to uniform flow distribution at the core inlet.

[0004] In order to improve the stability of the core, a secondary support structure is set at the bottom of the lower chamber in the existing pressure vessel. The secondary support structure is vertically arranged between the bottom surface of the lower head and the lower support plate. The structure is complex, which increases the fluid vortex in the lower chamber and is not conducive to the uniformity of the core inlet flow distribution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an improved reactor internal component and a pressure vessel system having the reactor internal component.

[0006] The present invention solves the technical problem by adopting a technical solution as follows: providing a reactor internal component, which is arranged in a pressure vessel, and includes an upper component, a lower component, a plurality of positioning assemblies, and a plurality of buffers; the plurality of positioning assemblies are arranged at intervals along the circumference of the upper component and the lower component to align and connect the upper component and the lower component;

[0007] The bottom edge of the lower member is constrained on the supporting step at the lower end of the pressure vessel away from the bottom edge of the upper member, and a plurality of buffer members are distributed at intervals along the circumference of the lower member and arranged between the lower member and the supporting step, and a gap is left between the buffer members and the supporting step or the lower member.

[0008] Preferably, the buffer member includes a horizontal main body portion extending radially along the pressure vessel and two deformable end portions integrally connected to the opposite ends of the horizontal main body portion; the deformable end portions are inclined relative to the horizontal main body portion toward the support step, forming an extrudable deformable space on the surface of the buffer member facing the support step, and the depth of the extrudable deformable space is the extrudable deformable height of the buffer member.

[0009] Preferably, the angle between the deformable end portion and the horizontal main portion is non-90°.

[0010] Preferably, the buffer is made of martensitic stainless steel.

[0011] Preferably, the positioning assembly includes a connecting plate, a first pin and a second pin arranged in a straight line and connected to the same surface of the connecting plate; the connecting plate is provided on the outer surface of the lower member facing the inner wall of the pressure vessel, and the first pin and the second pin both pass through the lower member to protrude from the inner surface of the lower member;

[0012] The bottom of the upper component is clamped on the first pin, and the top of the metal reflective layer inside the lower component is clamped on the second pin and aligned with the upper component.

[0013] Preferably, the gap height between the buffer and the supporting step or the lower component is matched with the centering height of the metal reflective layer and the upper component and the positioning assembly.

[0014] Preferably, the upper member includes an upper core plate, an upper support assembly spaced apart from the upper core plate, and a plurality of support columns; the plurality of support columns are vertically arranged and supported and connected between the upper support assembly and the upper core plate;

[0015] The lower component includes a hanging basket assembly, a lower support plate arranged at the bottom of the hanging basket assembly, and a metal reflective layer arranged on the inner periphery of the hanging basket assembly and supported on the lower support plate;

[0016] The upper component is fitted in the upper portion of the hanging basket assembly, and the core upper plate is centrally connected above the metal reflective layer through the positioning assembly.

[0017] Preferably, a first adjustment component for centering and clamping the first pin is provided on the lower surface of the core upper plate facing the metal reflective layer; and a second adjustment component for centering and clamping the second pin is provided on the top of the metal reflective layer.

[0018] Preferably, the first adjustment assembly includes two first adjustment blocks spaced apart from each other;

[0019] The second adjustment component includes two second adjustment blocks that are spaced apart.

[0020] Preferably, the lower component further comprises a flow distribution assembly connected below the lower support plate; the flow distribution assembly comprises a hemispherical flow distribution plate, and a hemispherical chamber is defined between the flow distribution plate and the lower support plate.

[0021] Preferably, the upper component further comprises a core measuring instrument guide assembly and a control rod guide tube for introducing core measuring instrument wires;

[0022] The core measuring instrument guide assembly is vertically arranged on the upper support assembly; the control rod guide tube is vertically arranged, passes through the upper support assembly and is connected to the core upper plate.

[0023] Preferably, the upper component also includes a plurality of upper positioning members; the plurality of upper positioning members are distributed at intervals along the circumference of the hanging basket assembly on the top of the hanging basket assembly, protruding toward the top cover of the pressure vessel, and are used for plugging and fitting with the top cover.

[0024] Preferably, the pressure vessel comprises a cylinder with upper and lower ends open, a top cover sealedly connected to the top of the cylinder, and a lower head sealedly connected to the bottom of the cylinder;

[0025] An inlet pipe and an outlet pipe are provided on the cylinder; the inlet pipe and the outlet pipe are located on different sides of the cylinder, and are at the same level on the cylinder.

[0026] The beneficial effects of the present invention are as follows: the upper and lower components of the in-core components are connected in a centering manner through a positioning assembly, thereby reducing the use of a large number of fasteners and the risk of fastener fatigue and falling off; by arranging a buffer part between the bottom of the in-core component and the supporting step at the lower end of the pressure vessel, the core drop support and drop buffering function are performed, and the secondary support structure below the in-core component is eliminated, thereby avoiding the problem of increased fluid vortex in the lower chamber and adverse effect on the uniformity of flow distribution at the core inlet caused by the secondary support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0028] FIG1 is a schematic longitudinal cross-sectional view of a pressure vessel system according to an embodiment of the present invention;

[0029] FIG2 is a schematic structural diagram of the upper component of the internal component in FIG1 ;

[0030] FIG3 is a schematic structural diagram of the lower component of the stack internals in FIG1 ;

[0031] FIG4 is a schematic diagram of a transverse cross-sectional structure of the pressure vessel system shown in FIG1 at the position of the lower component;

[0032] 5 is a schematic diagram of the longitudinal cross-sectional structure of the positioning assembly on the hanging basket assembly of the present invention;

[0033] FIG6 is a schematic diagram of the coordination structure of the positioning assembly between the core upper plate and the metal reflective layer in the present invention;

[0034] 7 is a schematic cross-sectional view of the buffer member at the lower support plate and the support step of the present invention;

[0035] FIG8 is an enlarged structural schematic diagram of the buffer member shown in FIG7 . DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0037] 1 , the reactor internals of the present invention are disposed in a pressure vessel 100 and form a pressure vessel system with the pressure vessel 100 , serving as one of the main equipment of the reactor.

[0038] 1 to 3 , in some embodiments, the internals may include an upper member 1, a lower member 2, a plurality of positioning assemblies 3, and a plurality of buffers 4. Within the pressure vessel 100, the lower member 2 is vertically disposed along the inner cavity of the pressure vessel 100, and the upper member 1 fits within the upper end of the lower member 2 and is centrally connected to the lower member 2.

[0039] In the present invention, several positioning assemblies 3 are arranged at intervals along the circumference of the upper member 1 and the lower member 2, aligning and connecting the upper and lower members 1 and 2. The bottom edge of the lower member 2, away from the upper member 1, is constrained to the support step 101 at the lower end of the pressure vessel 100. Several buffer members 4 are distributed at intervals along the circumference of the lower member 2, disposed between the lower member 2 and the support step 101, with gaps between the buffer members 4 and the support step 101 or the lower member 2.

[0040] The buffer 4 is set between the lower member 2 and the supporting step to support and buffer the core from falling. In the hypothetical working condition where the basket of the lower member 2 breaks, the buffer 4 absorbs the core falling load through compression deformation, and limits the rapid falling of the core in the lower member 2 under the mechanical buffering of the buffer 4, supports the core, ensures the integrity of the core, and reduces the peak impact load on the pressure vessel 100 when the core falls, ensuring the structural integrity of the pressure vessel 100. The buffer 4 is combined with the centering connection function of the above-mentioned positioning assembly 3 to ensure that the upper member 1 and the lower member 2 are still aligned after the core falls, ensure that the fuel assembly positioning pin is still inserted into the fuel assembly positioning pin hole, and ensure that the fuel assembly does not separate from the drive line, thereby ensuring the integrity of the core.

[0041] The buffer 4 can be fixed to the bottom edge of the lower member 2 with a gap between the buffer 4 and the support step; or the buffer 4 can be fixed to the surface of the support step 101 with a gap between the buffer 4 and the bottom edge of the lower member 2. The above gap settings ensure that the buffer 4 does not interfere with the support step or the lower member 2 in a hot functional environment.

[0042] In the pressure vessel 100, the upper component 1 of the reactor internals is mainly used to compress the core fuel assembly and provide guidance for the control rod assembly and core instrumentation. The lower component 2 is the main supporting structure of the core.

[0043] Specifically, the upper component 1 may include a core upper plate 10, an upper support assembly 20, a plurality of support columns 30, a core measurement instrument guide assembly 40, and a control rod guide tube 50, etc.

[0044] The core upper plate 10 and the upper support assembly 20 are arranged with a vertical distance therebetween. A plurality of support columns 30 are vertically arranged and supported between the upper support assembly 20 and the core upper plate 10 to connect the upper support assembly 20 and the core upper plate 10 together.

[0045] In the embodiment shown in Figure 2, the core upper plate 10 is a flat plate, and the upper support assembly 20 includes a support plate 21 and a side plate 22 extending vertically upward along the periphery of the support plate 21. The top of the side plate 22 is provided with a step plate 23 protruding radially outward. The step plate 23 cooperates with the upper shoulder of the pressure vessel 100, so that the upper support assembly 20 can be pressed and connected to the pressure vessel 100.

[0046] The core measurement instrument guide assembly 40 is vertically mounted on the upper support assembly 20 and is used to guide the core measurement instrument wires to measure the water level, temperature, and core reactivity at corresponding locations within the reactor. The core measurement instrument guide assembly 40 may include a guide cylinder, etc., the upper end of which can extend beyond the top cover of the pressure vessel 100 to connect to the core measurement instrument. This allows the core measurement instrument to be introduced from the top of the pressure vessel 100. Compared to the prior art method of introducing the core measurement instrument from the bottom, this simplifies the flow channel structure of the lower chamber of the pressure vessel 100, reduces fluid vortices in the lower chamber, reduces interference with the uniformity of flow distribution at the core inlet, and avoids the risk of high-level radioactive waste leakage from the bottom.

[0047] The wires of the core measuring instruments can pass through part of the support column 30 and enter the core and other relevant positions.

[0048] There is at least one control rod guide tube 50, and the number of control rod guide tubes 50 corresponds to the number of control rods in the core. The control rod guide tube 50 is vertically arranged, with one end facing the lower member 2. It passes through the upper support assembly 20 and is connected to the core upper plate 10. The upper end of the control rod guide tube 50 extends above the upper support assembly 20, facilitating the guidance and extraction of the control rods.

[0049] As shown in FIG3 , the lower member 2 may include a basket assembly 60, a lower support plate 70 disposed at the bottom of the basket assembly 60, and a metal reflective layer 80 disposed on the inner periphery of the basket assembly 60 and supported on the lower support plate 70. The basket assembly 60 may further include a basket body 61 and a basket flange 62 formed on the top of the basket body 61; the basket body 61 is vertically disposed along the entire inner cavity of the pressure vessel 100, and the basket flange 62 may overlap with the top of the upper support assembly 20 and the compression spring and be compressed and connected to the upper end of the pressure vessel 100.

[0050] The lower support plate 70 is combined with the lower core plate at the bottom of the basket assembly 60, or is formed by thickening the lower core plate. Compared with the existing internal components, the lower core plate is eliminated, which can reduce the overall height of the reactor and improve the overall stability of the reactor.

[0051] In the pressure vessel 100 , the lower support plate 70 serves as the bottom of the hanging basket assembly 60 . The lower support plate 70 is constrained on the support step 101 at the lower end of the pressure vessel 100 through its own periphery.

[0052] The upper member 1 fits within the upper end of the basket assembly 60 (specifically, the basket body 61). A metal reflector 80 is positioned within the lower end of the basket assembly 60 and supported on a lower support plate 70. This divides the interior of the basket assembly 60 into the reactor upper chamber 201 and the reactor core chamber 202 via the upper core plate 10 of the upper member 1. The metal reflector 80 is positioned along the inner periphery of the lower end of the basket assembly 60. The inner contour of the metal reflector 80 forms the core contour, and the outer periphery, corresponding to the distribution of the core fuel assemblies, forms a polygonal structure, as shown in Figure 4. The metal reflector 80 forms a protective perimeter for the core fuel assemblies, ensuring fuel assembly installation while limiting ineffective bypass flow.

[0053] Fuel assembly locating pins are provided on the core upper plate 10 and the lower support plate 70 for guiding and positioning the fuel assembly. The outer surface of the hanging basket body 61 can be provided with an irradiation sample monitoring tube bracket 63 to provide installation, positioning and insertion and removal channels for the irradiation sample monitoring tube.

[0054] The metal reflector 80 can further be a cylindrical structure made of metal material, or formed by fully welding multiple metal plates. The core region where the metal reflector 80 is located has no fasteners. Fasteners in the core active area are removed to eliminate fasteners from the core chamber, thus reducing the risk of fasteners falling off.

[0055] The core upper plate 10 is centrally connected above the metal reflective layer 80 through the positioning assembly 3 .

[0056] Compared to existing reactor internals that employ heat shielding plates on the outer wall of the hanging basket to shield the core from neutrons, the present invention eliminates the heat shielding plates and instead installs a metal reflective layer 80 within the hanging basket body 61. By utilizing the water cavity between the pressure vessel 100 and the hanging basket assembly 60 and the metal reflective layer 80 to shield the reactor core from radioactivity, the lower component 2 is more evenly distributed, with its center of gravity close to the central axis, facilitating horizontal adjustment during lifting. Simultaneously, the annular flow path between the pressure vessel 100 and the reactor internals is optimized to reduce flow resistance.

[0057] The lower member 2 further includes a plurality of upper locating members 203 ; the plurality of upper locating members 203 are spaced apart along the circumference of the basket assembly 60 at the top of the basket assembly 60 , protruding toward the top cover of the pressure vessel 100 , and configured to engage with the top cover of the pressure vessel 100 . The upper locating members 203 may be locating pins disposed on the basket flange 62 of the basket assembly 60 .

[0058] The upper positioning member 203 is combined with the positioning assembly 3 and the support step 101 to achieve the centering of the internal components in the pressure vessel 100 at the upper, middle and lower parts, and to achieve the overall centering of the internal components and the pressure vessel 100, thereby limiting the relative displacement between the two.

[0059] The lower member 2 further includes a flow distribution assembly 90 connected below the lower support plate 70 .

[0060] Preferably, the flow distribution assembly 90 includes a hemispherical flow distribution plate, the periphery of which is mated and connected to the periphery of the lower support plate 70 at the bottom of the basket assembly 60, so as to achieve flow distribution covering the entire core. A hemispherical chamber is defined between the flow distribution plate and the lower support plate 70. A uniform and smooth fitting gap is formed between the flow distribution plate and the inner surface of the spherical lower head 130 of the pressure vessel 100. As the lower chamber of the pressure vessel 100, the uniform and smooth fitting gap achieves relatively uniform core flow distribution, and after secondary flow distribution through the water holes on the lower support plate 70, excellent uniform core inlet flow distribution is obtained.

[0061] In combination with the specific composition of the upper member 1 and the lower member 2 , the positioning assembly 3 ensures the alignment of the core upper plate 10 and the lower support plate 70 , thereby ensuring the axial position accuracy of the fuel assembly in the core chamber.

[0062] 3 , 5 and 6 , in some embodiments, the positioning assembly 3 may further include a connecting plate 31 , a first pin 32 and a second pin 33 arranged on the same surface of the connecting plate 31 ; the first pin 32 and the second pin 33 are in a straight line on the surface of the connecting plate 31 and are arranged at intervals.

[0063] On the internal components, a connecting plate 31 is mounted on the outer surface of the lower component 2 (specifically, the hanging basket assembly 60) facing the inner wall of the pressure vessel 100. A first pin 32 and a second pin 33 both pass through the lower component 2 and protrude from its inner surface, that is, toward the inside of the hanging basket assembly 60. The first pin 32 is positioned above the upper component 1, while the second pin 33 is positioned below the metal reflective layer 80. The bottom of the upper component 1 is secured to the first pin 31, while the top of the metal reflective layer 80 of the lower component 2 is secured to the second pin 33 and aligned with the upper component 1.

[0064] Specifically, the upper component 1 engages the first pin 32 with its core upper plate 10. To this end, a first adjustment assembly 11 for centering and engaging the first pin 32 may be provided on the lower surface of the core upper plate 10 facing the metal reflective layer 80. Similarly, a second adjustment assembly 12 for centering and engaging the second pin 33 is provided on the top of the metal reflective layer 80.

[0065] Alternatively, the first adjustment assembly 11 may include two first adjustment blocks spaced apart, with the spacing groove between the two first adjustment blocks being snapped onto the first pin 32; the second adjustment assembly 12 may include two second adjustment blocks spaced apart, with the spacing groove between the two second adjustment blocks being snapped onto the second pin 33. It is understood that the spacing grooves of the first adjustment assembly 11 and the spacing grooves of the second adjustment assembly 12 may also be formed on the core upper plate 10 and the metal reflective layer 80, respectively.

[0066] In conjunction with Figures 1 and 7 and 8, the buffer member 4 is specifically arranged between the lower support plate 70 and the support step 101. In a preferred embodiment, the buffer member 4 can structurally include a horizontal main body 41 and two deformable end portions 42 integrally connected to opposite ends of the horizontal main body 41. Between the lower support plate 70 and the support step 101 of the lower member 2, the horizontal main body 41 is arranged between the lower member 2 and the support step 101 along the radial extension direction of the pressure vessel 100, and can be fixed to the periphery of the lower support plate 70 of the lower member 2, or installed in reverse and fixed to the surface of the support step 101. The two deformable end portions 42 respectively correspond to the radial direction of the pressure vessel 100 and face the inner wall surface of the pressure vessel 100 and the center direction of the lower support plate 70.

[0067] The deformable end portion 42 is inclined relative to the horizontal main portion 41 toward the support step 101, forming an extrudable space on the surface of the buffer member 4 facing the support step 101. The depth of this extrudable space is equal to the extrudable height h of the buffer member 4. When the buffer member 4 is subjected to an impact load, the compressible space compresses the deformable end portion 42, thereby providing a cushioning and shock-absorbing function for the lower member 2.

[0068] The angle between the deformable end portion 42 and the horizontal main portion 41 is not 90 degrees. The angle between the deformable end portion 42 and the horizontal main portion 41 on the side facing the lower support plate 70 is preferably 0°-60°, while the angle between the deformable end portion 42 and the horizontal main portion 41 on the side facing the surface of the support step 101 is an obtuse angle.

[0069] Preferably, the buffer member 4 is made of martensitic stainless steel.

[0070] Furthermore, a gap is provided between the buffer member 4 and the support step 101 or the lower support plate 70 of the lower member 2. The gap height matches the centering height of the metal reflective layer 80, the upper member 1, and the positioning assembly 3. Specifically, preferably, the engagement length (i.e., the longitudinal engagement height) between the first adjustment assembly 11 and the first pin 32 matches the gap height, for example, the engagement length is greater than or equal to the gap height. The gap height also matches the axial length of the fuel assembly locating pins (e.g., the fuel assembly locating pins on the core upper plate 10), further ensuring that the fuel assembly locating pins remain inserted into the fuel assembly locating pin holes after the core falls, preventing the fuel assembly from disengaging from the drive lines and maintaining core integrity.

[0071] As shown in FIG1 , the pressure vessel 100 may specifically include a cylinder 110 with open ends, a top cover 120 sealed to the top of the cylinder 110, and a lower head 130 sealed to the bottom of the cylinder 110. An inlet pipe 111 and an outlet pipe 112 are provided on the cylinder 110; the inlet pipe 111 and the outlet pipe 112 are located on different sides of the cylinder 110 and are at the same level on the cylinder 110.

[0072] There may be one or more inlet pipes 111 ; there may be one or more outlet pipes 112 .

[0073] The inlet pipe 111 and the outlet pipe 112 are located at the same horizontal elevation on the cylinder 110, which helps reduce the height of the pressure vessel 100 and improve the structural reliability. As shown in Figures 1 and 3, the basket body 61 of the basket assembly 60 is provided with a basket outlet 64 at a position corresponding to the outlet pipe 112. The basket outlet 64 is directly opposite and connected to the outlet pipe 112.

[0074] Alternatively, the basket outlet 64 may be an extended nozzle structure that can be snugly docked with the outlet pipe 112 .

[0075] The pressure vessel system further includes a thermal sleeve 200 ; the thermal sleeve 200 is installed in the control rod drive mechanism socket on the top cover 120 of the pressure vessel 100 , providing a channel for the control rod drive rod and improving the nuclear fuel control rod drop time.

[0076] In the pressure vessel system of the present invention, the core components form an in-core coolant flow channel within the pressure vessel 100. Coolant enters the pressure vessel 100 through the inlet pipe 111, flows along the annular cavity between the basket body 61 and the pressure vessel 100, and enters the lower chamber of the pressure vessel 100. It is then directed and redistributed by the flow distribution assembly 90, and then re-distributed through the lower support plate 70 to enter the core. It then enters the reactor upper chamber 201 through the water holes in the core upper plate 10 above the core, and finally flows out of the core through the basket outlet 64 and outlet pipe 112. The reactor control rod drive mechanism is mounted on the top cover 120 of the pressure vessel 100. Together with the thermowell 200, the control rod guide tube 50, and the fuel assembly, it forms the reactor drive line, providing guidance for the control rods to enter and exit the core. Core measurement instruments are introduced into the core through the pressure vessel 100 top cover 120 and the core measurement instrument guide assembly 40, enabling measurement of water level, temperature, and neutron flux at corresponding locations within the core.

[0077] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A reactor internal component, characterized in that: The internal components are arranged in a pressure vessel, and include an upper component, a lower component, a plurality of positioning assemblies, and a plurality of buffers; the plurality of positioning assemblies are arranged at intervals along the circumference of the upper component and the lower component to align and connect the upper component and the lower component; The bottom edge of the lower member is constrained on the supporting step at the lower end of the pressure vessel away from the bottom edge of the upper member, and a plurality of buffer members are distributed at intervals along the circumference of the lower member and arranged between the lower member and the supporting step, and a gap is left between the buffer members and the supporting step or the lower member.

2. The reactor internals according to claim 1, characterized in that: The buffer member includes a horizontal main body portion extending radially along the pressure vessel and two deformable end portions integrally connected to the opposite ends of the horizontal main body portion; the deformable end portions are inclined relative to the horizontal main body portion toward the support step, forming an extrudable deformable space on the surface of the buffer member facing the support step, and the depth of the extrudable deformable space is the extrudable deformable height of the buffer member.

3. The reactor internals according to claim 2, characterized in that: The angle between the deformable end portion and the horizontal main portion is non-90°.

4. The reactor internals according to claim 1, wherein: The buffer is made of martensitic stainless steel.

5. The reactor internals according to claim 1, characterized in that: The positioning assembly includes a connecting plate, a first pin and a second pin arranged in a straight line and connected to the same surface of the connecting plate; the connecting plate is provided on the outer surface of the lower member facing the inner wall of the pressure vessel, and the first pin and the second pin both pass through the lower member to protrude from the inner surface of the lower member; The bottom of the upper component is clamped on the first pin, and the top of the metal reflective layer inside the lower component is clamped on the second pin and aligned with the upper component.

6. The reactor internals according to claim 5, characterized in that: The height of the gap between the buffer and the supporting step or the lower component is matched with the centering height of the metal reflective layer and the upper component and the positioning assembly.

7. The reactor internals according to claim 5, characterized in that: The upper member includes an upper core plate, an upper support assembly spaced apart from the upper core plate, and a plurality of support columns; the plurality of support columns are vertically arranged and supported and connected between the upper support assembly and the upper core plate; The lower component includes a hanging basket assembly, a lower support plate arranged at the bottom of the hanging basket assembly, and a metal reflective layer arranged on the inner periphery of the hanging basket assembly and supported on the lower support plate; The upper component is fitted in the upper portion of the hanging basket assembly, and the core upper plate is centrally connected above the metal reflective layer through the positioning assembly.

8. The reactor internals according to claim 7, characterized in that: A first adjustment component for centering and clamping the first pin is provided on the lower surface of the core upper plate facing the metal reflective layer; a second adjustment component for centering and clamping the second pin is provided on the top of the metal reflective layer.

9. The reactor internals according to claim 8, characterized in that: The first adjustment component includes two first adjustment blocks spaced apart; The second adjustment component includes two second adjustment blocks that are spaced apart.

10. The reactor internals according to claim 7, characterized in that: The lower component further comprises a flow distribution assembly connected below the lower support plate; the flow distribution assembly comprises a hemispherical flow distribution plate, and a hemispherical chamber is defined between the flow distribution plate and the lower support plate.

11. The reactor internals according to claim 7, characterized in that: The upper component also includes a core measuring instrument guide assembly and a control rod guide tube for introducing core measuring instrument wires; The core measuring instrument guide assembly is vertically arranged on the upper support assembly; the control rod guide tube is vertically arranged, passes through the upper support assembly and is connected to the core upper plate.

12. The reactor internals according to claim 7, characterized in that: The upper component also includes a plurality of upper positioning members; the plurality of upper positioning members are distributed at intervals along the circumference of the hanging basket assembly on the top of the hanging basket assembly, protruding toward the top cover of the pressure vessel, and are used for plugging and matching with the top cover.

13. A pressure vessel system, characterized in that: The invention comprises a pressure vessel and the in-pile component according to any one of claims 1 to 12, wherein the in-pile component is arranged in the pressure vessel.

14. The pressure vessel system according to claim 13, wherein: The pressure vessel comprises a cylinder with upper and lower ends open, a top cover sealedly connected to the top of the cylinder, and a lower head sealedly connected to the bottom of the cylinder; An inlet pipe and an outlet pipe are provided on the cylinder; the inlet pipe and the outlet pipe are located on different sides of the cylinder, and are at the same level on the cylinder.

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