Nuclear reactor heat exchanger

Abstract

The utility model discloses a nuclear reactor heat exchanger which comprises a shell, a first heat exchange tube unit and a second heat exchange tube unit, wherein the first heat exchange tube unit and the second heat exchange tube unit are arranged in the shell; a first water inlet, a first water outlet and a third water outlet are formed in the first end part of the shell, a second water inlet and a second water outlet are formed in the side wall of the shell, and a third water inlet is formed in the second end part of the shell; the first water inlet, the first heat exchange tube unit and the first water outlet are sequentially communicated to form a first heat exchange channel; the second water inlet, the second heat exchange tube unit and the second water outlet are sequentially communicated to form a second heat exchange channel; the third water inlet is communicated with the third water outlet through the inner space of the shell. The heat exchanger can integrate the functions of a conventional pressurized water reactor nuclear power station downflow heat exchanger and a regenerative heat exchanger, is applied to a conventional pressurized water reactor nuclear power station chemical and volume control system to replace the downflow heat exchanger and the regenerative heat exchanger, simplifies the system design, and saves the space cost.

Description

Technical Field

[0001] This utility model relates to a heat exchanger, and more particularly to a nuclear reactor heat exchanger. Background Technology

[0002] The chemical and volume control system of a conventional pressurized water reactor nuclear power plant consists of four parts: the drain loop, the cleanup loop, the charge loop, and the shaft seal water and excess drain loop. Additionally, there is a low-pressure drain line and a boron removal line. Under normal steady-state operation, the drain flow originates from the cold end of loop 2 (Unit 4) or loop 3 (Unit 3) of the primary loop, passes through two pneumatic isolation valves, and enters the regenerative heat exchanger, reducing the temperature of the drain flow to 140°C. Simultaneously, the temperature of the charge flow on the tube side rises from 54°C to 266°C. The drain flow then passes through three sets of parallel pressure-reducing orifice plates, reducing the pressure of the drain flow to 2.4 MPa.a. The drain line exits the reactor building via a through-hole and enters the nuclear auxiliary building. The drain flow then passes through a pneumatic isolation valve into the tube side of the drain heat exchanger. The downflow is depressurized again to 0.2-0.3 MPa after passing through the downflow control valve and then enters the filter. After filtering out suspended particles larger than 5μm in the coolant, it flows into the purification circuit. After passing through the resin filter, the purified flow is reinjected into the primary circuit by the charging pump.

[0003] As can be seen from the above design, the chemical and volumetric control systems of conventional large pressurized water reactor nuclear power plants currently require two heat exchangers to perform cooling and reheating functions respectively. This type of design involves a large number of such devices. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an integrated nuclear reactor heat exchanger.

[0005] The technical solution adopted by this utility model to solve its technical problem is: to provide a nuclear reactor heat exchanger, including a sealed and hollow shell, a first heat exchange tube unit and a second heat exchange tube unit disposed inside the shell; a first water inlet, a first water outlet and a third water outlet are provided on the first end of the shell, a second water inlet and a second water outlet are provided on the side wall of the shell, and a third water inlet is provided on the second end of the shell;

[0006] The first water inlet, the first heat exchange tube unit, and the first water outlet are connected in sequence to form a first heat exchange channel; the second water inlet, the second heat exchange tube unit, and the second water outlet are connected in sequence to form a second heat exchange channel; the third water inlet is connected to the third water outlet through the internal space of the outer shell.

[0007] In one embodiment, the outer shell includes a cylindrical body open at both ends, and a first end cap and a second end cap respectively connected to opposite ends of the cylindrical body;

[0008] The first water inlet, the first water outlet, and the third water outlet are disposed on the first end cap, the third water inlet is disposed on the second end cap, the second water inlet is disposed on the end of the cylinder near the first end cap, and the second water outlet is disposed on the end of the cylinder near the second end cap.

[0009] In one embodiment, the nuclear reactor heat exchanger further includes a first tube sheet and a second tube sheet disposed at opposite ends of the outer shell, and a connecting pipe disposed within the outer shell;

[0010] The first tube sheet is provided with a first internal channel, the first outlet is connected to one side of the first tube sheet and communicates with the first internal channel, and the outlet of the first heat exchange tube unit is connected to the other side of the first tube sheet and communicates with the first internal channel.

[0011] The second tube sheet is provided with a second internal channel. The water inlet end of the first heat exchange tube unit is connected to one side of the second tube sheet and communicates with the second internal channel. One end of the connecting pipe is connected to the first water inlet, and the other end extends to the other side of the second tube sheet and communicates with the second internal channel.

[0012] In one embodiment, the first heat exchange tube unit includes a first spiral coil, and the second heat exchange tube unit includes a second spiral coil;

[0013] Inside the outer casing, the second spiral coil is arranged around the periphery of the first spiral coil.

[0014] In one embodiment, the first heat exchange tube unit includes two sets of the first spiral coils, which are intertwined and symmetrically arranged relative to the central axis of the outer shell; the connecting pipe has two pipes, each corresponding to one of the two sets of the first spiral coils; the first end of the outer shell is provided with two first water inlets and two first water outlets;

[0015] The first internal channel within the first tube sheet includes two isolated first flow collection channels that are symmetrical about the central axis of the outer shell, and the two first flow collection channels are respectively connected to the corresponding first outlet; the second internal channel within the second tube sheet includes two isolated second flow collection channels that are symmetrical about the central axis of the outer shell.

[0016] The outlet end of each of the first spiral coils is connected to the corresponding first collection channel, and the inlet end is connected to the corresponding second collection channel; the two second collection channels are respectively connected to the corresponding connecting pipes and connected to the corresponding second inlets through the connecting pipes.

[0017] In one embodiment, the connecting pipe is a J-shaped pipe, with the straight section of the connecting pipe located in the inner ring of the first spiral coil and connected to the first water inlet, and the bend of the connecting pipe located on the side of the second tube sheet facing away from the first spiral coil and connected to the second tube sheet.

[0018] In one embodiment, the nuclear reactor heat exchanger further includes a central cylinder disposed within the outer shell and a sleeve surrounding the central cylinder;

[0019] The gap between the sleeve and the central cylinder forms a first annular cavity, and the gap between the central cylinder and the inner wall of the outer shell forms a second annular cavity; the first heat exchange tube unit is disposed in the first annular cavity, and the second heat exchange tube unit is disposed in the second annular cavity.

[0020] In one embodiment, the central cylinder has at least one water hole on its wall, which connects the first annular cavity and the internal channel of the central cylinder.

[0021] In one embodiment, the sleeve has at least one through hole on its wall, which connects the first annular cavity and the second annular cavity.

[0022] In one embodiment, the nuclear reactor heat exchanger further includes a drain pipe that is inserted into the interior of the outer shell from a first end of the outer shell and extends into a second end of the outer shell.

[0023] The beneficial effects of this utility model are as follows: By setting a first heat exchange tube unit and a second heat exchange tube unit in the heat exchanger, two heat exchange channels are formed, which can exchange heat with the fluid flowing through the shell side respectively. This allows the integration of the functions of the downflow heat exchanger and the regenerative heat exchanger in a conventional pressurized water reactor nuclear power plant. It can be used in the chemical and volume control system of a conventional pressurized water reactor nuclear power plant to replace the downflow heat exchanger and the regenerative heat exchanger, simplifying system design and saving space costs. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0025] Figure 1 This is a longitudinal cross-sectional structural diagram of a nuclear reactor heat exchanger according to an embodiment of the present invention;

[0026] Figure 2 This is a top view of a nuclear reactor heat exchanger according to an embodiment of the present invention;

[0027] Figure 3 yes Figure 1 The diagram shows a cross-sectional view of the nuclear reactor heat exchanger along line AA. Detailed Implementation

[0028] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0029] like Figures 1-3 As shown, a nuclear reactor heat exchanger according to an embodiment of the present invention includes a sealed and hollow outer shell 10, a first heat exchange tube unit 20 and a second heat exchange tube unit 30 disposed inside the outer shell 10.

[0030] The outer casing 10 has a first end and a second end. The first end of the outer casing 10 is provided with a first inlet 41, a first outlet 51 and a third outlet 53. The side wall of the outer casing 10 is provided with a second inlet 42 and a second outlet 52. The second end of the outer casing 10 is provided with a third inlet 43. The first inlet 41, the first heat exchange tube unit and the first outlet 51 are connected in sequence to form a first heat exchange channel. The second inlet 42, the second heat exchange tube unit and the second outlet 52 are connected in sequence to form a second heat exchange channel. The third inlet 43 is connected to the third outlet 53 through the internal space of the outer casing 10.

[0031] The first and second heat exchange channels are both pipe-side channels, serving as cold-side fluid channels. Cooling water enters the first heat exchange channel from the first inlet 41, and the low-temperature primary coolant enters the second heat exchange channel from the second inlet 42. The internal space of the outer shell 10, connected to the third inlet 43 and the third outlet 53, forms a shell-side channel, serving as a hot-side fluid channel. The high-temperature primary coolant enters the outer shell 10 from the third inlet 43, flows along the internal space of the outer shell 10, and exchanges heat with the cold water / low-temperature primary coolant in the first and second heat exchange channels during its flow. It then exits from the third outlet 53.

[0032] Specifically, the outer shell 10 is structurally formed by connecting multiple components, which may include a cylindrical body 13 with open ends, and a first end cap 11 and a second end cap 12 respectively connected to opposite ends of the cylindrical body 13; the first end cap 11 and the second end cap 12 also simultaneously close the opposite open ends of the cylindrical body 13.

[0033] The first inlet 41, the first outlet 51, and the third outlet 53 are preferably located on the first end cap 11, the third inlet 43 is located on the second end cap 12, the second inlet 42 is located at the end of the cylinder 13 near the first end cap 11, and the second outlet 52 is located at the end of the cylinder 13 near the second end cap 12. (Using a heat exchanger as an example...) Figure 1Taking the vertical placement as an example, the first end cap 11 is on top, the second end cap 12 is on the bottom, the first inlet 41, the first outlet 51, and the third outlet 53 are located at the top of the outer shell 10, the third inlet 43 is located at the bottom of the outer shell 10, the second inlet 42 is located at the upper end of the outer shell 10, and the second outlet 52 is located at the lower end of the outer shell 10. Thus, the cold-side fluid enters the outer shell 10 from the top and flows downwards along the first and second heat exchange channels, respectively. The hot-side fluid enters the outer shell 10 from the bottom and flows upwards along the outer shell 10, exchanging heat with the cold-side fluid in the first and second heat exchange channels, fully utilizing the thermal energy of the hot-side fluid and reducing heat loss. After heat exchange, the cold-side fluid flows upwards and exits from the top of the outer shell 10, and the hot-side fluid also flows upwards and exits from the top of the outer shell 10. The inflow and outflow directions of the cold-side and hot-side fluids are as follows: Figure 1 As indicated by the middle arrow.

[0034] The first heat exchange tube unit 20 may include a first spiral coil, and the second heat exchange tube unit 30 includes a second spiral coil. Inside the outer casing 10, the first spiral coil is a spiral structure with the central axis of the outer casing 10 as its axis, and the second spiral coil is also a spiral structure with the central axis of the outer casing 10 as its axis, and the second spiral coil is arranged around the periphery of the first spiral coil. Therefore, inside the outer casing 10, the second heat exchange tube unit 30 is located between the first heat exchange tube unit 20 and the inner wall of the outer casing 10.

[0035] The inlet and outlet of the first spiral coil are connected to the first inlet 41 and the first outlet 51, respectively, and the inlet and outlet of the second spiral coil are connected to the second inlet 42 and the second outlet 52, respectively.

[0036] The first spiral coil includes several spiral heat exchange tubes, and the second spiral coil includes several spiral heat exchange tubes.

[0037] Furthermore, the nuclear reactor heat exchanger may also include a first tube sheet 61 and a second tube sheet 62 disposed within the outer shell 10. The first tube sheet 61 may be disposed between the cylinder 13 and the first head 11, and the second tube sheet 62 may be disposed between the cylinder 13 and the second head 12.

[0038] The first tube sheet 61 and the second tube sheet 62 also serve as flow collection devices. Specifically, the first tube sheet 61 has a first internal channel 610, and a first outlet 51 is connected to the side of the first tube sheet 61 facing the first end cap 11 and communicates with the first internal channel 610. The outlet end of the first heat exchange tube unit 20 is connected to the other side of the first tube sheet 61 and communicates with the first internal channel 610. The second tube sheet 62 has a second internal channel 620, and the inlet end of the first heat exchange tube unit 20 is connected to the side of the second tube sheet 62 facing away from the second end cap 12 and communicates with the second internal channel 620; the other side of the second tube sheet 62 is connected to the first inlet 41. The fluid (such as cold-side fluid) enters the second internal channel 620 of the second tube sheet 62 from the first inlet 41, enters the first heat exchange tube unit 20 through the second internal channel 620, flows along the first heat exchange tube unit 20 to the first tube sheet 61 and enters the first internal channel 610, accumulates in the first internal channel 610 and is then discharged from the outer shell 10 from the first outlet 51.

[0039] Since both the first inlet 41 and the first outlet 51 are located on the first end cap 11, in order to connect the first inlet 41 to the water inlet end of the first heat exchange tube unit 20 located on the side of the second end cap 12, a connecting pipe 63 is provided inside the outer shell 10. One end of the connecting pipe 63 is connected to the first inlet 41, and the other end extends along the outer shell 10 to connect to the second tube sheet 62, so as to connect to the water inlet end of the first heat exchange tube unit 20 through the second internal channel 620 of the second tube sheet 62.

[0040] The side of the second tube sheet 62 facing inward toward the cylinder 13 is connected to the water inlet of the first heat exchange tube unit 20. Preferably, the side of the second tube sheet 62 facing the second end cap 12 is connected to the connecting pipe 63. The connecting pipe 63 can be a J-shaped pipe, thus having a straight section 631 and a bend 632. The straight section 631 of the connecting pipe 63 connects to the first water inlet 41, and the bend 632 of the connecting pipe 63 is located on the side of the second tube sheet 62 facing the second end cap 12 and connects to the second tube sheet 62, and is connected to the second internal channel 620.

[0041] Alternatively, the first heat exchange tube unit 20 may include two sets of first spiral coils. The first end of the outer shell 10 is provided with two first water inlets 41 and two first water outlets 51. The outer shell 10 is provided with two connecting pipes 63, thereby forming two first heat exchange channels. The two heat exchange channels are independent of each other and do not affect each other, thus improving the reliability of the heat exchanger.

[0042] Two sets of first spiral coils are intertwined and arranged symmetrically with respect to the central axis of the outer shell 10. This arrangement of two sets of first spiral coils does not increase the diameter of the first heat exchange tube unit 20 compared to a single set, thus eliminating the need to increase the size of the outer shell 10. This allows for full utilization of the internal space of the outer shell 10, resulting in a compact and reasonable structure. The straight section 631 of the connecting pipe 63 is located within the inner ring of the first spiral coil.

[0043] Corresponding to the two sets of first spiral coils, the first internal channel 610 within the first tube sheet 61 includes two isolated first collecting channels symmetrical about the central axis of the outer shell 10. Each of the two first collecting channels is connected to a corresponding first outlet 51. The second internal channel 620 within the second tube sheet 62 includes two isolated second collecting channels symmetrical about the central axis of the outer shell 10. Each of the two second collecting channels is connected to a corresponding second inlet 42 via its own connecting pipe 63. The outlet end of each first spiral coil is connected to the corresponding first collecting channel, and the inlet end of each first spiral coil is connected to the corresponding second collecting channel.

[0044] For the first internal channel 610 to include two first collecting channels, the first tube sheet 61 can be an integral plate structure, and the first internal channel 610 is an annular channel set inside the plate structure, which is divided into two first collecting channels by the setting of internal partitions of the annular channel. Alternatively, the first tube sheet 61 is formed by the joining of two semicircular plates, and each semicircular plate is provided with a first collecting channel.

[0045] For the second internal channel 620, which includes two second collection channels, the second tube sheet 62 can be an integral plate structure, and the second internal channel 620 is an annular channel located inside the plate structure. The annular channel is divided into two second collection channels by a partition inside the annular channel. Alternatively, the second tube sheet 62 can be formed by joining two semicircular plates, with each semicircular plate containing a second collection channel.

[0046] Furthermore, combined Figure 1 and Figure 3 In some embodiments, the nuclear reactor heat exchanger further includes a central cylinder 101 disposed within the outer shell 10 and a sleeve 102 sleeved around the central cylinder 101. The gap between the sleeve 102 and the central cylinder 101 forms a first annular cavity 110, and the gap between the central cylinder 101 and the inner wall of the outer shell 10 forms a second annular cavity 120; a first heat exchange tube unit 20 is disposed within the first annular cavity 110, and a second heat exchange tube unit 30 is disposed within the second annular cavity 120.

[0047] like Figure 1As shown, one end of the central cylinder 101 and the sleeve 102 can be fixedly connected to the first tube sheet 61, and the other end of the central cylinder 101 and the sleeve 102 can be fixedly connected to the second tube sheet 62, so that the central cylinder 101 and the sleeve 102 are connected and fixed between the first tube sheet 61 and the second tube sheet 62.

[0048] The edge of the first tube sheet 61 can abut against the end of the cylinder 13, thereby fixing and supporting it inside the outer shell 10; the outer circumference of the second tube sheet 62 is smaller than the inner circumference of the outer shell 10, so that the second tube sheet 62 is suspended below the first tube sheet 61 through the central cylinder 101 and the sleeve 102, so that the force of the second tube sheet 62, the central cylinder 101 and the sleeve 102 is borne by the first tube sheet 61.

[0049] Furthermore, the first tube sheet 61 and the second tube sheet 62 are both annular plates, and the central holes of the first tube sheet 61 and the second tube sheet 62 are respectively directly connected to the internal channel of the central cylinder 101. The connecting pipe 63 passes through the internal channel of the central cylinder 101, and can also be connected to the inner wall of the central cylinder 101 through a fixing clamp 633 to improve stability.

[0050] The central cylinder 101 has at least one water hole on its wall, connecting the first annular cavity 110 and the internal channel of the central cylinder 101; the sleeve 102 has at least one through hole on its wall, connecting the first annular cavity 110 and the second annular cavity 120. Thus, fluid (such as hot-side fluid) entering the housing 10 from the third inlet 43 is diverted within the housing 10 into the first annular cavity 110 and the second annular cavity 120. The fluid in the second annular cavity 120, after heat exchange, can enter the first annular cavity 110 through the through hole on the sleeve 102, and together with the fluid in the first annular cavity 110, enter the internal channel of the central cylinder 101 through the water hole on the central cylinder 101, and then exit from the third outlet 53.

[0051] To meet the drainage function during heat exchanger maintenance, the nuclear reactor heat exchanger also includes a drain pipe 70, which is inserted into the interior of the outer shell 10 from the first end of the outer shell 10 and extends to the second end of the outer shell 10.

[0052] This invention relates to a nuclear reactor heat exchanger, which is applied in the chemical and volume control system of a conventional large pressurized water reactor nuclear power plant. Under normal steady-state operation, the outflow is drawn from the cold end of the primary loop, passes through two pneumatic isolation valves, and enters the outer shell 10 through the third inlet 43. After heat exchange, it is cooled and discharged from the third outlet 53. The outflow is then depressurized through three sets of parallel pressure-reducing orifice plates. The outflow pipeline exits the reactor building through a through-hole and enters the nuclear auxiliary building. The outflow passes through a pneumatic isolation valve and enters the tube side of the integrated heat exchanger, that is, it enters the first heat exchange channel through the second inlet 42 to exchange heat with the fluid inside the outer shell 10, and then exits from the second outlet 52.

[0053] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A nuclear reactor heat exchanger, characterized in that, It includes a sealed and hollow outer shell, a first heat exchange tube unit and a second heat exchange tube unit disposed inside the outer shell; a first water inlet, a first water outlet and a third water outlet are provided on the first end of the outer shell, a second water inlet and a second water outlet are provided on the side wall of the outer shell, and a third water inlet is provided on the second end of the outer shell; The first water inlet, the first heat exchange tube unit, and the first water outlet are connected in sequence to form a first heat exchange channel; the second water inlet, the second heat exchange tube unit, and the second water outlet are connected in sequence to form a second heat exchange channel; the third water inlet is connected to the third water outlet through the internal space of the outer shell.

2. The nuclear reactor heat exchanger according to claim 1, characterized in that, The outer shell includes a cylindrical body open at both ends, and a first end cap and a second end cap respectively connected to opposite ends of the cylindrical body; The first water inlet, the first water outlet, and the third water outlet are disposed on the first end cap, the third water inlet is disposed on the second end cap, the second water inlet is disposed on the end of the cylinder near the first end cap, and the second water outlet is disposed on the end of the cylinder near the second end cap.

3. The nuclear reactor heat exchanger according to claim 1, characterized in that, The nuclear reactor heat exchanger also includes a first tube sheet and a second tube sheet disposed at opposite ends of the outer shell, and a connecting pipe disposed within the outer shell. The first tube sheet is provided with a first internal channel, the first outlet is connected to one side of the first tube sheet and communicates with the first internal channel, and the outlet of the first heat exchange tube unit is connected to the other side of the first tube sheet and communicates with the first internal channel. The second tube sheet is provided with a second internal channel. The water inlet end of the first heat exchange tube unit is connected to one side of the second tube sheet and communicates with the second internal channel. One end of the connecting pipe is connected to the first water inlet, and the other end extends to the other side of the second tube sheet and communicates with the second internal channel.

4. The nuclear reactor heat exchanger according to claim 3, characterized in that, The first heat exchange tube unit includes a first spiral coil, and the second heat exchange tube unit includes a second spiral coil; Inside the outer casing, the second spiral coil is arranged around the periphery of the first spiral coil.

5. The nuclear reactor heat exchanger according to claim 4, characterized in that, The first heat exchange tube unit includes two sets of the first spiral coils, which are intertwined and symmetrically arranged relative to the central axis of the outer shell; the connecting pipe has two pipes, each corresponding to one of the two sets of the first spiral coils; the first end of the outer shell is provided with two first water inlets and two first water outlets. The first internal channel within the first tube sheet includes two isolated first flow collection channels that are symmetrical about the central axis of the outer shell, and the two first flow collection channels are respectively connected to the corresponding first outlet; the second internal channel within the second tube sheet includes two isolated second flow collection channels that are symmetrical about the central axis of the outer shell. The outlet end of each of the first spiral coils is connected to the corresponding first collection channel, and the inlet end is connected to the corresponding second collection channel; the two second collection channels are respectively connected to the corresponding connecting pipes and connected to the corresponding second inlets through the connecting pipes.

6. The nuclear reactor heat exchanger according to claim 5, characterized in that, The connecting pipe is a J-shaped pipe. The straight part of the connecting pipe is located in the inner ring of the first spiral coil and is connected to the first water inlet. The bent part of the connecting pipe is located on the side of the second tube sheet facing away from the first spiral coil and is connected to the second tube sheet.

7. The nuclear reactor heat exchanger according to any one of claims 1-6, characterized in that, The nuclear reactor heat exchanger also includes a central cylinder disposed inside the outer shell and a sleeve fitted around the central cylinder; The gap between the sleeve and the central cylinder forms a first annular cavity, and the gap between the central cylinder and the inner wall of the outer shell forms a second annular cavity; the first heat exchange tube unit is disposed in the first annular cavity, and the second heat exchange tube unit is disposed in the second annular cavity.

8. The nuclear reactor heat exchanger according to claim 7, characterized in that, The central cylinder has at least one water hole on its wall, which connects the first annular cavity and the internal channel of the central cylinder.

9. The nuclear reactor heat exchanger according to claim 7, characterized in that, The sleeve has at least one through hole on its wall, which connects the first annular cavity and the second annular cavity.

10. The nuclear reactor heat exchanger according to any one of claims 1-6, characterized in that, The nuclear reactor heat exchanger also includes a drain pipe that is inserted into the interior of the outer shell from a first end and extends into the second end of the outer shell.

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