Coolant transport structures for reactors

Abstract

The embodiment of the present invention discloses a coolant transmission structure for a reactor, wherein a power pump is arranged in the reactor, and the coolant transmission structure comprises: a transmission pipe, one end of which is connected to the power pump, and the other end of which is connected to the reactor, and the power pump is used to push the coolant to flow in the transmission pipe; and a support part, which is fixed to the reactor and connected to the transmission pipe to at least partially eliminate the resonance between the transmission pipe and the power pump. This coolant transmission structure has high rigidity, which prevents it from resonating with the power pump, and can increase displacement constraints under seismic loads, thereby improving the strength of the connection parts of the coolant transmission structure.

Description

Technical Field

[0001] The invention relates to the technical field of nuclear reactors, and in particular to a coolant transmission structure for a reactor. Background Art

[0002] The primary cooling system is one of the main systems in the reactor. When the coolant in the primary cooling system passes through the core, the fission energy generated in the fuel elements is discharged from the core to maintain the normal working conditions of the core and ensure the safe operation of the reactor. In the primary cooling system, the power pump is used to circulate the primary coolant, and the coolant is circulated between the power pump and the reactor through the coolant transmission structure. Since the coolant transmission structure is immersed in the coolant, the coolant transmission structure is required to have a high rigidity to prevent it from breaking and affecting the safe operation of the reactor. Summary of the invention

[0003] In view of the above problems, the present invention is proposed to provide a coolant transport structure for a reactor that overcomes the above problems or at least partially solves the above problems.

[0004] A first aspect of an embodiment of the present invention provides a coolant transmission structure for a reactor, wherein a power pump is provided in the reactor, and the coolant transmission structure comprises: a transmission pipe, one end of which is connected to the power pump, and the other end of which is communicated with the reactor, and the power pump is used to push the coolant to flow in the transmission pipe; and a supporting part, which is fixed to the reactor and connected to the transmission pipe to at least partially eliminate the resonance between the transmission pipe and the power pump.

[0005] A second aspect of an embodiment of the present invention provides a reactor, comprising: a power pump; and a coolant transmission structure provided by the first aspect of an embodiment of the present invention, wherein the coolant transmission structure is connected to the power pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other objects and advantages of the present invention will become apparent from the following description of the present invention with reference to the accompanying drawings, which will help to provide a comprehensive understanding of the present invention.

[0007] Figure 1 is a schematic structural diagram of a coolant transmission structure for a reactor provided according to an embodiment of the present invention;

[0008] Figure 2 is a schematic structural diagram of a support portion of a coolant transmission structure for a reactor provided according to an embodiment of the present invention;

[0009] Figure 3is a schematic structural diagram of a transmission pipe of a coolant transmission structure for a reactor provided according to an embodiment of the present invention;

[0010] Figure 4 is based on Figure 3 A partial schematic structural diagram of the transmission pipe provided;

[0011] Figure 5 It is a schematic diagram of the application process of the coolant transmission structure for a reactor provided according to an embodiment of the present invention.

[0012] In the accompanying drawings, 10 is a power pump, 11 is a support plate, 12 is a grid plate header, 13 is a core, 14 is an in-core support, 20 is a transmission pipe, 21 is a bending section, 30 is a support portion, 31 is a bellows, 32 is an extension piece, 40 is a joint, 41 is a connecting portion, 42 is a snap-fit ​​portion, 43 is a transition section, 50 is a sealing portion, 60 is a three-way joint, and 70 is a support pipe.

[0013] It should be noted that the drawings are not drawn to scale, and for illustrative purposes, elements of similar structure or function are generally represented by similar reference numerals throughout the drawings. It should also be noted that the drawings are only for the convenience of describing the preferred embodiments, not the invention itself. The drawings do not illustrate every aspect of the described embodiments and do not limit the scope of the invention. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiment is one embodiment of the present invention, not all embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0016] The primary cooling system in the reactor plays the role of discharging the heat generated by the core, and the coolant transmission structure plays the role of transmitting coolant in the primary cooling system. Specifically, the coolant transmission structure transmits the coolant from the power pump to the reactor core. When the coolant in the primary cooling system passes through the core, the fission energy generated in the fuel elements of the core is discharged from the core, maintaining the normal working conditions of the core and ensuring the safe operation of the reactor.

[0017] Optionally, the reactor here may be a pool-type fast reactor, specifically, the reactor may be a China Demonstration Fast Reactor; the coolant may be liquid sodium or liquid lead-bismuth alloy, etc.

[0018] One embodiment of the present invention provides a coolant transmission structure for a reactor, wherein a power pump 10 is provided in the reactor. Optionally, the power pump 10 may be a centrifugal pump. When the pump is filled with coolant, the impeller rotates to generate centrifugal force. The coolant in the impeller channel is thrown to the periphery and flows into the pump casing under the action of the centrifugal force. At this time, the pressure at the center of the impeller decreases, and the pressure is lower than the pressure in the tube. The coolant flows into the impeller under the action of the pressure difference, so that the centrifugal pump can continuously inhale the coolant, thereby completing the circulation of the coolant. In other embodiments, those skilled in the art may select other types of power pumps to provide power for coolant transmission according to actual conditions. Figure 1 is a schematic structural diagram of a coolant transmission structure for a reactor provided by an embodiment of the present invention, see Figure 1 , the coolant transmission structure includes:

[0019] A transmission pipe 20, one end of which is connected to the power pump 10, and the other end of which is connected to the reactor. The power pump 10 is used to push the coolant to flow in the transmission pipe 20; optionally, one end of the transmission pipe 20 can be connected to the pump support of the power pump 10. Compared with being directly connected to the power pump 10, the pump support can buffer the transmission pipe 20 to reduce the rotational frequency resonance between the transmission pipe 20 and the power pump 10. Optionally, the transmission pipe 20 can be a pressure pipe. Specifically, the reactor includes a grid header 12, which is used to support the core 13. The transmission pipe 20 can be connected to the grid header 12 so that the coolant enters the grid header 12, thereby cooling the core 13.

[0020] The support part 30 is fixed to the reactor, and the support part 30 is connected to the transmission pipe 20 to at least partially eliminate the resonance between the transmission pipe 20 and the power pump 10. Specifically, the support part 30 can increase the rigidity of the coolant transmission structure, thereby eliminating the rotational frequency resonance between the transmission pipe 20 and the power pump 10. In an embodiment of the present invention, the transmission pipe 20 can pass through the support part 30, so that the support part 30 constrains the transmission pipe 20, thereby at least partially eliminating the resonance between the transmission pipe 20 and the power pump 10. In other embodiments, the support part 30 can be circumferentially arranged outside the transmission pipe 20. Optionally, the support part 30 can also be a support rod, which is clamped outside the transmission pipe 20 to constrain the transmission pipe 20, thereby avoiding the rotational frequency resonance between the transmission pipe 20 and the power pump 10.

[0021] The coolant transmission structure in the reactor is immersed in the coolant. Due to the influence of the additional mass of the coolant, the stiffness of the coolant transmission structure will be reduced by about 40%, so that the stiffness requirements of the coolant transmission structure are higher. By providing a support portion 30 in the transmission pipe 20, the overall stiffness of the coolant transmission structure can be improved by increasing the support stiffness.

[0022] Optionally, the support portion 30 and the transmission pipe 20 may be integrally formed, and the support portion 30 and the transmission pipe 20 may also be welded via a flange, which facilitates operation during on-site installation.

[0023] Figure 2 is a schematic structural diagram of a support portion of a coolant transmission structure for a reactor provided according to an embodiment of the present invention, see Figure 2 In an embodiment of the present invention, the support portion 30 may include a bellows 31, and the transmission pipe 20 is arranged to pass through the bellows 31. The bellows 31 can be used to compensate for the displacement of the transmission pipe 20 under the seismic load, thereby improving the strength of the connection between the transmission pipe 20 and the support portion 30, the connection between the transmission pipe 20 and the power pump 10, and the connection between the transmission pipe 20 and the reactor. In other embodiments, the support portion 30 may include an elastic member, which is circumferentially arranged on the transmission pipe 20 to compensate for the displacement of the transmission pipe 20 under the seismic load. Optionally, the transmission pipe 20 may include two pipes, and the elastic member is arranged between the two pipes to compensate for the displacement of the transmission pipe 20 under the seismic load. In some embodiments, the elastic member can be used in conjunction with the bellows 31 to obtain better displacement compensation and eliminate the effect of frequency conversion resonance between the transmission pipe 20 and the power pump 10.

[0024] See also Figure 1 and Figure 2 The support part 30 also includes an extension 32, which fixes the bellows 31 to the reactor to improve the stability of the support part 30, thereby improving the stability of the coolant transmission structure, and further improving the effect of the support part 30 on eliminating resonance and displacement compensation of the transmission pipe 20. Optionally, the support part 30 can be directly fixed to the reactor, which can save space in the reactor. Specifically, those skilled in the art can understand that the reactor includes an in-core support 14, which is a support structure in the reactor for supporting the core 13 and other equipment. Those skilled in the art can understand that the in-core support 14 can include a support plate 11 and a grid header 12, and the grid header 12 can support and fix the core 13, and during the operation of the reactor, reasonably distribute the coolant flow to the core 13 and other equipment in the reactor. The support part 30 can be fixed to the in-core support 14. For example, the support part 30 can be fixed to the support plate 11 of the in-core support 14. The bellows 31 can also be used to compensate for the thermal displacement difference between the coolant transmission structure and the in-piler support 14, as well as the displacement difference between the coolant transmission structure and the in-piler support 14 under seismic load. Those skilled in the art can understand that the thermal displacement difference and displacement difference between the coolant transmission structure and the in-piler support 14, that is, the thermal displacement difference and displacement difference between the transmission pipe 20 and the in-piler support 14, that is, displacement compensation for the transmission pipe 20 is equivalent to displacement compensation for the coolant transmission structure.

[0025] In the embodiment of the present invention, the transmission pipe 20 includes at least one curved section 21, which is arranged in the reactor in coordination with other equipment in the reactor, thereby improving the utilization rate of the space in the reactor and saving the space in the reactor.

[0026] Since the transmission pipe 20 includes at least one curved section 21, that is, the transmission pipe 20 adopts a spatial bending structure and is a thin-walled complex structure, so that its overall rigidity is relatively small, therefore, the support portion 30 is also required to improve the rigidity of the coolant transmission structure.

[0027] In one embodiment of the present invention, specifically, the transmission pipe 20 may include a curved pipe section and two straight pipe sections, and the curved pipe is disposed between the two straight pipe sections. Optionally, the curved pipe and the straight pipe may be connected by welding or may be integrally formed.

[0028] In an embodiment of the present invention, the support portion 30 can be connected to one end close to the bending section 21, that is, the support portion 30 can be connected to one end of the transmission tube 20 close to the bending section 21 to improve the strength of the bending section 21 of the transmission tube 20.

[0029] In an embodiment of the present invention, the support portion 30 may also be directly connected to the curved section 21 to further improve the strength of the curved section 21 of the transmission tube 20 .

[0030] When the coolant flows in the transmission pipe 20, friction pressure drop, acceleration pressure drop and gravity pressure drop will be generated, and a local pressure drop will be generated at the bending section 21. Therefore, setting the support part 30 at one end of the transmission pipe 20 close to the bending section 21, or setting the support part 30 at the bending section 21, can reduce the impact of the pressure drop and improve the strength of the bending section 21, thereby preventing the transmission pipe 20 from breaking.

[0031] In some embodiments, the support portion 30 may also be connected to one end of the transmission pipe 20 close to the power pump 10, so as to further improve the effect of eliminating the rotational frequency resonance between the transmission pipe 20 and the power pump 10. Optionally, a support portion 30 may also be provided at one end of the transmission pipe 20 close to the power pump 10 and at one end close to the curved section 21. This arrangement method may further improve the strength of the transmission pipe 20, and has a better effect on eliminating the rotational frequency resonance between the transmission pipe 20 and the power pump 10 and performing displacement compensation on the transmission pipe 20, but this arrangement method will occupy more space in the reactor. In actual applications, those skilled in the art may comprehensively consider factors such as the size of the space in the reactor, the effect of eliminating resonance, improving strength, and displacement compensation, and select a suitable position and quantity to set the support portion 30.

[0032] Figure 3is a schematic structural diagram of a transmission pipe of a coolant transmission structure for a reactor provided according to an embodiment of the present invention, Figure 4 is based on Figure 3 A partial schematic structural diagram of the transmission tube is provided, see Figure 3 and Figure 4 A joint 40 is provided at one end of the transmission pipe 20 connected to the reactor.

[0033] The coolant transmission structure further includes a sealing portion 50, which is disposed at the joint 40 to prevent the coolant from flowing out of the joint 40 when flowing into the reactor. Optionally, the sealing portion 50 may be a sealing ring.

[0034] See also Figure 4 , the joint 40 comprises:

[0035] A connecting portion 41, the connecting portion 41 is used to connect the transmission tube 20 and the reactor;

[0036] The engaging portion 42 is disposed on the connecting portion 41 and is used to connect the joint 40 and the reactor.

[0037] In an embodiment of the present invention, the transmission tube 20 is connected to the reactor via a joint 40. In other embodiments, the transmission tube 20 may also be directly inserted into the reactor.

[0038] In the embodiment of the present invention, a transition section 43 is provided between the connecting portion 41 and the engaging portion 42 to compensate for the axial deformation of the joint 40. Specifically, the transition section 43 can reduce the stress generated when the coolant flows to the reactor, and can also compensate for the displacement caused by the thermal expansion of the transmission tube 20.

[0039] In one embodiment of the present invention, specifically, the connecting portion 41 may include two sections of straight pipes, a transition section is arranged between the two sections of straight pipes, the locking portion 42 may include a connecting pipe and a connecting pipe, the connecting pipe is arranged on the connecting portion 41, the connecting pipe is arranged on the connecting pipe, and the connecting pipe is used to connect to the reactor, specifically, the connecting pipe can be connected to the in-core support 14, and the connecting pipe can be connected to the grid header 12.

[0040] See also Figure 3 and Figure 4 , the coolant transmission structure also includes:

[0041] The three-way joint 60 is used to connect the transmission pipe 20 and the power pump 10, so that the coolant in the power pump 10 enters the reactor through two outlets, making the circulation efficiency of the coolant in the reactor higher.

[0042] In an embodiment of the present invention, a sealing ring may be provided at the connection between the three-way joint 60 and the power pump 10. Specifically, the three-way joint 60 is connected to the outlet pipe of the power pump 10, and the outlet pipe of the power pump 10 can be directly inserted into the three-way joint 60. The difference in thermal expansion coefficients between the materials of the sealing ring and the outlet pipe of the power pump 10 is utilized to reduce the hot gap, thereby reducing leakage.

[0043] In an embodiment of the present invention, at least one support pipe 70 may be circumferentially arranged at one end of the three-way joint 60 connected to the power pump 10, and the support pipe 70 connects the three-way joint 60 and the power pump 10. Optionally, a coolant channel is arranged in the support pipe 70, and the coolant enters the pump suction chamber of the power pump 10 through the coolant channel in the support pipe 70.

[0044] In an embodiment of the present invention, the coolant transmission structure may further include a compensating portion (not shown in the figure), which may be provided on the transmission pipe 20 to compensate for the axial deformation of the transmission pipe 20. Optionally, the compensating portion may be a C-shaped expansion joint. In other embodiments, the compensating portion may also be a U-shaped expansion joint or a bellows expansion joint. Those skilled in the art may select a compensating portion of a suitable shape or type according to the needs of the actual situation and the ease of installation.

[0045] In an embodiment of the present invention, the coolant transmission structure may further include a measuring unit (not shown in the figure), which may be arranged on the transmission pipe 20. Specifically, the measuring unit may be arranged on one end of the transmission pipe 20 connected to the power pump 10, or may be arranged on one end of the transmission pipe 20 connected to the reactor. In an embodiment of the present invention, the measuring unit may be a thermocouple, which is used to measure the temperature of the coolant flowing into the transmission pipe 20 and / or flowing out of the transmission pipe 20, and to monitor the temperature of the coolant circulating in the reactor in real time. In other embodiments, the measuring unit may also be a flow meter, which is used to measure the flow rate of the coolant flowing into the transmission pipe 20 and / or flowing out of the transmission pipe 20, and to monitor the flow rate data of the coolant passing through the loop in real time. The flow rate data may be used to determine whether the cooling system of the first loop of the reactor is operating normally, and at the same time, it may be determined whether the transmission pipe 20 of the coolant transmission structure is blocked, deformed, or other abnormal phenomena, so as to understand the operating status of the reactor in real time and enable the reactor to operate safely.

[0046] In an embodiment of the present invention, specifically, during the installation and manufacturing process, the transmission pipe 20 and / or the three-way joint 60 can be subjected to a strength test, the test medium is distilled water, the metal temperature during the test is not lower than 10°C, the test pressure is 0.84MPa, and during the test, the test pressure is gradually increased evenly and slowly to the test pressure, maintained for at least 30 minutes, and then the pressure is slowly reduced to 0.63MPa and maintained until the end of the inspection to detect whether the transmission pipe 20 and / or the three-way joint 60 has any breakage, leakage, penetration and visible residual deformation.

[0047] In an embodiment of the present invention, specifically, during the installation and manufacturing process, after the coolant transmission structure is welded to the pump support connecting sleeve of the power pump 10 and the grid header 12 of the reactor, a strength test and a leakage test are carried out together. The strength test medium is nitrogen, and the test pressure is 0.7MPa. During the test, the pressure gradually increases to the test pressure and is maintained for 30 minutes. Then, the pressure is reduced to 0.53MPa and maintained for a required period of time to detect whether there is a pressure drop and visible residual deformation.

[0048] After the strength test, a leakage test can be carried out. The medium is a mixture of nitrogen and helium. The test pressure is 0.53MPa. The helium tracer gas concentration is not less than 10% volume concentration under the test pressure. The allowable leakage rate is 6.7×10-6 / m 3 Pa / s.

[0049] The embodiment of the present invention has been applied to the China Demonstration Fast Reactor. During the application process, the support part 30 adopts a two-wave bellows structure, the wave pitch is set to 196mm, the thickness is set to 8mm, and the outer diameter is set to 1616mm. The maximum axial thermal displacement difference under the design working condition that can be compensated by the bellows structure is 9.5mm, the maximum axial displacement difference under the seismic load that can be compensated is 2.3mm, the maximum lateral thermal displacement difference under the design working condition that can be compensated is 5.1mm, and the maximum lateral displacement difference under the seismic load that can be compensated is 7.4mm. In addition, the strength, stability and fatigue of the bellows structure have certain margins.

[0050] In application, specifically, the upper part of the bellows is welded to the transmission pipe 20 through a flange, and the lower part of the bellows is fixed to the supporting middle plate of the in-pile support 14 through a connecting tube. This structure increases the natural frequency of the one-loop coolant transmission structure in the sodium liquid from 10.9HZ to 21.5HZ, effectively avoiding the resonance of the coolant transmission structure and the rotation frequency of the power pump 10.

[0051] Figure 5 is a schematic diagram of the application process of the coolant transmission structure for a reactor provided according to an embodiment of the present invention, see Figure 5 The power pump 10 provides power for coolant transmission, pushing the coolant into the grid header 12 along the direction of the arrow in the transmission pipe 20, and then into the core 13 from the grid header 12 along the direction of the arrow to cool the core 13.

[0052] In an embodiment of the present invention, the reactor can be a pool-type sodium-cooled fast reactor, in which metallic sodium is selected as the coolant. The transmission pipe 20 is immersed in the cold sodium pool, and the power pump 10 draws sodium from the cold sodium pool. Optionally, the power pump 10 can draw sodium from the cold sodium pool via the support pipe 70. The power pump 10 delivers the cold sodium to the grid header 12 via the transmission pipe 20, thereby cooling the core 13 and other equipment in the reactor. After the cold sodium absorbs the heat generated by the core 13, it enters the hot sodium pool, thereby completing the circulation of the coolant in the first loop of the reactor.

[0053] An embodiment of the present invention provides a reactor, which includes: a power pump 10 and a coolant transmission structure for the reactor provided by the embodiment of the present invention, wherein the coolant transmission structure is connected to the power pump 10 .

[0054] The embodiment of the present invention improves the overall stiffness of the coolant transmission structure by arranging a support portion 30 on the transmission pipe 20, which can effectively avoid the frequency resonance between the coolant transmission structure and the power pump 10. In addition, through the support portion 30, while improving the support stiffness, it effectively realizes the displacement compensation of the coolant transmission structure under seismic load, improves the strength of the connection part of the coolant transmission structure, and provides a guarantee for the safe and reliable operation of the reactor.

[0055] Regarding the embodiments of the present invention, it should also be noted that, in the absence of conflict, the embodiments of the present invention and the features therein may be combined with each other to obtain new embodiments.

[0056] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. The protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A coolant transmission structure for a reactor, wherein a power pump (10) is arranged in the reactor, characterized in that: The coolant transmission structure comprises: a transmission pipe (20), one end of the transmission pipe (20) being connected to the power pump (10), the other end of the transmission pipe (20) being in communication with the reactor, the power pump (10) being used to push the coolant to flow in the transmission pipe (20); A support portion (30), the support portion (30) being fixed to the reactor, the support portion (30) being connected to the transmission pipe (20) so as to at least partially eliminate resonance between the transmission pipe (20) and the power pump (10); The supporting portion (30) comprises a bellows (31) and an extension piece (32), and the transmission pipe (20) is arranged to pass through the bellows (31); The upper portion of the bellows (31) is welded to the transmission pipe (20) via a flange, and the extension piece (32) fixes the bellows (31) to a support plate (11) of an in-core support (14) in the reactor.

2. The coolant transmission structure according to claim 1, characterized in that: The transmission pipe (20) comprises at least one curved section (21).

3. The coolant transmission structure according to claim 2, characterized in that: The supporting portion (30) is connected to an end close to the curved section (21).

4. The coolant transmission structure according to claim 2, characterized in that: The supporting portion (30) is connected to the curved section (21).

5. The coolant transmission structure according to claim 1, characterized in that: The support portion (30) is connected to an end of the transmission pipe (20) close to the power pump (10).

6. The coolant transmission structure according to claim 1, characterized in that: One end of the transmission pipe (20) connected to the reactor is provided with a joint (40).

7. The coolant transmission structure according to claim 6, characterized in that: Also includes: A sealing portion (50) is provided on the joint (40) and is used to prevent the coolant from flowing out of the joint (40) when flowing into the reactor.

8. The coolant transmission structure according to claim 6, characterized in that: The joint (40) comprises: a connecting portion (41), the connecting portion (41) being used to connect the transmission pipe (20) and the reactor; A snap-fit ​​portion (42), the snap-fit ​​portion (42) being arranged on the connecting portion (41) and being used to connect the joint (40) and the reactor.

9. The coolant transmission structure according to claim 8, characterized in that: A transition section (43) is provided between the communication portion (41) and the locking portion (42) to compensate for axial deformation of the joint (40).

10. The coolant transmission structure according to claim 1, characterized in that: Also includes: A three-way joint (60) is used to connect the transmission pipe (20) and the power pump (10), so that the coolant in the power pump (10) enters the reactor through two outlets.

11. A reactor, characterized in that: include: Power pump (10); The coolant transmission structure according to any one of claims 1 to 10, wherein the coolant transmission structure is connected to the power pump (10).

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