Sodium cooled Fast Reactor sodium-air heat exchanger with straight heat transfer pipes

Abstract

A sodium-air heat exchanger according to the present disclosure may comprise: a vertically erected tubular body through which air flows; a heat transfer tube bundle arranged longitudinally within the tubular body through which sodium flows; an upper duct installed at the top of the tubular body through which sodium is introduced and air is discharged; and a lower duct installed at the bottom of the tubular body through which sodium is discharged and air is introduced.

Description

Technology Field

[0001] The present disclosure relates to a heat exchanger used in a sodium-cooled fast reactor. Background Technology

[0003] Sodium-cooled fast reactors use sodium as a coolant. Sodium-cooled fast reactors have the advantages of high nuclear fuel utilization, no need for high pressure, high thermal efficiency, and the ability to utilize spent nuclear fuel.

[0004] Due to the high chemical reactivity of sodium, there is a possibility of direct leakage of radioactive materials in sodium-cooled fast reactors caused by the failure of the pressure boundary of the primary heat transfer system (PHTS) in the event of a sodium-water reaction accident. To address this, sodium-cooled fast reactors are equipped with an intermediate heat transfer system (ITHS) that uses sodium as the working fluid.

[0005] However, since there is still a possibility of accidents caused by the sodium-water reaction, it is necessary to develop measures to prevent them at the source. Prior art literature

[0007] Korean Patent Publication No. 10-2023-0071687 (May 23, 2023) The problem to be solved

[0008] According to the present disclosure, a sodium-air heat exchanger with enhanced safety can be provided by using air for heat exchange with sodium in a sodium-cooled fast reactor. means of solving the problem

[0010] A sodium-air heat exchanger according to the present disclosure may comprise: a vertically erected tubular body through which air flows; a heat transfer tube bundle arranged longitudinally within the tubular body through which sodium flows; an upper duct installed on the upper part of the tubular body through which sodium is introduced and air is discharged; and a lower duct installed on the lower part of the tubular body through which sodium is discharged and air is introduced.

[0011] In addition, sodium flows from the upper side to the lower side in the heat transfer tube bundle and air flows from the lower side to the upper side in the straight tube body so that the sodium and air can exchange heat with each other.

[0012] In addition, the upper duct may be configured to include an upper duct sodium section that forms a sodium inlet on the upper side and communicates with the heat transfer tube bundle, and an upper duct air section in which the upper part of the straight body is inserted and installed for a set length and an air outlet is formed on the side.

[0013] In addition, the air outlet is formed to be located above the upper end of the straight body, and the inner wall of the upper duct air section is formed to form a width set on the inner surface of the upper duct air section, thereby forming a downward flow path leading to the air outlet.

[0014] In addition, the lower duct may be configured to include a lower duct sodium section that forms a sodium outlet on the lower side and communicates with the heat transfer tube bundle, and a lower duct air section in which the lower part of the straight body is inserted and installed for a set length and an air inlet is formed on the side.

[0015] In addition, the air inlet is formed to be located above the lower end of the straight body, and the inner wall of the lower duct air section is formed to form a width set on the inner surface of the lower duct air section, thereby forming an upward flow path leading to the air inlet.

[0016] In addition, a corrugated tube may be installed around the outer circumference of the above-mentioned tubular body for a set length.

[0017] In addition, a plurality of spacer grids, into which the heat transfer tube bundles are inserted and supported, can be installed at set intervals inside the above-mentioned tubular body.

[0018] In addition, the spacer grid may be formed with a plurality of insertion holes into which the heat transfer tube bundle is inserted and a plurality of grid holes formed between the insertion holes.

[0019] In addition, a support member may be installed on one side of the corrugated tube to vertically support the straight body. Effects of the invention

[0021] According to the present disclosure, by using air for heat exchange, it is possible to prevent accidents caused by a rapid reaction between sodium and water, thereby increasing safety.

[0022] In addition, excluding safety devices for the reaction between sodium and water has the effect of increasing the economic efficiency of the sodium-cooled fast reactor. Brief explanation of the drawing

[0024] FIG. 1 is a perspective view of a sodium-air heat exchanger according to the present disclosure. Figure 2 is an enlarged perspective view of the upper part of Figure 1. Figure 3 is an enlarged perspective view of the lower part of Figure 1. Figure 4 is a side view of the top of Figure 1. Figure 5 is a side view of the lower part in Figure 1. Figure 6 is a partial cross-sectional view of Figure 1. Figure 7 is a drawing showing a spacer grid. FIG. 8 is a side view of a sodium-air heat exchanger according to the present disclosure. Specific details for implementing the invention

[0025] The present disclosure is described in detail below with reference to the attached drawings. However, this is merely an example and is not limited to the specific embodiments illustratively described in the present disclosure.

[0026]

[0027] The sodium-air heat exchanger according to the present disclosure can be used in a sodium-cooled fast reactor that uses sodium as a coolant.

[0028] ​Referring to FIGS. 1 to 3, a sodium-air heat exchanger (100) according to the present disclosure may be configured to include a straight body (110), a heat transfer tube bundle (120), an upper duct (130), and a lower duct (140).

[0029] The tubular body (110) can be configured in a cylindrical shape with a top and bottom through it. The tubular body (110) is formed long in the longitudinal direction and can be erected vertically on the ground.

[0030] A heat transfer tube bundle (120) is formed by gathering multiple heat transfer tubes and can be arranged longitudinally inside a tubular body (110). Sodium (10) can flow in the heat transfer tube bundle (120).

[0031] The upper duct (130) is installed on the upper part of the straight body (110), and sodium (10) can be introduced and air (20) can be discharged.

[0032] The lower duct (140) is installed at the bottom of the straight body (110), and sodium (10) can be discharged and air (20) can be introduced.

[0033] Sodium (10) flows from the upper side to the lower side in the heat transfer tube bundle (120) and air (20) flows from the lower side to the upper side in the straight tube body (110) so that the sodium (10) and air (20) can exchange heat with each other.

[0034] By using air (10) instead of water as the heat exchange medium with sodium (10), the possibility of a reaction accident caused by contact between sodium and water can be fundamentally eliminated.

[0035] Referring to FIG. 4, the upper duct (130) may be configured to include an upper duct sodium section (131) that forms a sodium inlet (1311) on the upper side and communicates with a heat transfer tube bundle (120), and an upper duct air section (132) that is installed by inserting the upper part of a straight body (110) to a set length and forms an air outlet (1321) on the side.

[0036] The upper duct (130) may be composed of an upper duct sodium section (131) and an upper duct air section (132). The upper duct sodium section (131) and the upper duct air section (132) may be formed to be separated from each other within the upper duct (130). The upper duct sodium section (131) and the upper duct air section (132) may be formed to be separated internally so as not to communicate with each other.

[0037] The upper duct sodium section (131) has a sodium inlet (1311) formed on the upper side so that sodium (10) can be introduced from the sodium inlet (1311). The heat transfer tube bundle (120) is connected to the upper duct sodium section (131) so that the sodium (10) introduced through the sodium inlet (1311) can flow into the heat transfer tube bundle (120).

[0038] The upper duct air section (132) flows into the lower duct (140), allowing the air (20) that has risen through the inside of the straight body (110) to flow out.

[0039] The upper part of the tubular body (110) is inserted into the upper duct air section (132), and the upper part of the tubular body (110) can be installed by being inserted for a set length. The upper duct air section (132) has an air outlet (1321) formed on its side so that air (20) can be discharged through the air outlet (1321).

[0040] The air outlet (1321) is formed to be located below the upper end of the straight body (110), and the upper duct air section inner wall (1322) is formed to form a width set on the inner surface of the upper duct air section (132) to form a downward flow path (1323) leading to the air outlet (1321).

[0041] The upper part of the tubular body (110) can be installed by being inserted into the upper duct air section (132) for a set length. An air outlet (1321) can be formed on the side of the upper duct air section (132) so as to be located below the end of the upper part of the tubular body (110).

[0042] On the inner surface of the upper duct air section (132), an upper duct air section inner wall (1322) is formed to form a set width, thereby forming a downward flow path (1323) which is a space through which air (20) can flow.

[0043] The downward flow path (1323) can form a flow path through which air (20) rising from the tubular body (110) can flow to an air outlet (1321) located below the end of the tubular body (110). The flow of air (20) through this downward flow path (1323) allows the air (20) to be supplied uniformly in the radial direction and prevents overcooling.

[0044] Referring to FIG. 5, the lower duct (140) may be configured to include a lower duct sodium section (141) that forms a sodium outlet (1411) on the lower side and communicates with a heat transfer tube bundle (120), and a lower duct air section (142) that is installed by inserting the lower part of a straight body (110) to a set length and forms an air inlet (1421) on the side.

[0045] The lower duct (140) may be composed of a lower duct sodium section (141) and a lower duct air section (142). The lower duct sodium section (141) and the lower duct air section (142) may be formed to be separated from each other within the lower duct (140). The lower duct sodium section (141) and the lower duct air section (142) may be formed to be separated internally so as not to communicate with each other.

[0046] The lower duct sodium section (141) forms a sodium inlet (1411) on the lower side so that sodium (10) can be discharged from the sodium outlet (1411). The heat transfer tube bundle (120) is connected to communicate with the lower duct sodium section (141) so that sodium (10) can come out of the heat transfer tube bundle (120) and flow from the lower duct sodium section (141) to the sodium outlet (1411).

[0047] Air (20) can be introduced into the lower duct air section (142), rise through the inside of the straight body (110), and exit through the upper duct air section (132).

[0048] The lower part of the tubular body (110) is inserted into the lower duct air section (142), and the lower part of the tubular body (110) can be inserted and installed for a set length. The lower duct air section (142) has an air inlet (1421) formed on its side so that air (20) can be introduced through the air inlet (1421).

[0049] The air inlet (1421) is formed to be located above the lower end of the straight body (110), and the lower duct air section inner wall (1422) is formed to form a width set on the inner surface of the lower duct air section (142) to form an upward flow path (1423) leading to the air inlet (1421).

[0050] The lower part of the tubular body (110) can be installed by being inserted into the lower duct air section (142) for a set length. An air inlet (1421) can be formed on the side of the lower duct air section (142) so as to be located below the end of the lower part of the tubular body (110).

[0051] On the inner surface of the lower duct air section (142), an inner wall (1422) of the lower duct air section is formed to form a set width, thereby forming an upward flow path (1423) which is a space through which air (20) can flow.

[0052] The upward flow path (1423) can form a flow path through which air (20) rising from the tubular body (110) can flow to an air inlet (1421) located above the end of the tubular body (110). The flow of air (20) through this upward flow path (1423) allows the air (20) to be supplied uniformly in the radial direction and prevents overcooling.

[0053] Sodium (10) flowing into the upper duct (130) is about 400 degrees Celsius, and air (20) flowing into the lower duct (140) is about 20 degrees Celsius. The high-temperature sodium (10) and the low-temperature air (20) exchange heat with each other inside the straight-tube body (110), so that the sodium (10) becomes about 150 to 200 degrees Celsius and flows out of the lower duct (140), and the air (20) becomes about 300 degrees Celsius and flows out of the upper duct (130).

[0054] Sodium (10) flows inside the heat transfer tube bundle (120) and air (20) flows inside the tubular body (110), and the sodium (10) and air (20) can exchange heat with each other inside the tubular body (110) without the sodium (10) and air (20) coming into contact.

[0055] Referring to Fig. 6, a corrugated tube (150) can be installed around the outer circumference of the tubular body (110) with a set length.

[0056] The corrugated tube (150) can be installed to wrap around the outer circumference of the tubular body (110). The corrugated tube (150) can be installed to wrap around the tubular body (110) for a length set along the longitudinal direction of the tubular body (110).

[0057] The corrugated tube (150) can absorb mechanical loads that may be caused by the thermal expansion and contraction of the heat transfer tube bundle (120) due to the inflow of high / low temperature sodium (10).

[0058] Referring to FIG. 7, a plurality of spacer grids (160) in which a heat transfer tube bundle (110) is inserted and supported can be installed at set intervals inside the tubular body (110).

[0059] The spacer grid (160) can be formed with a plurality of insertion holes (161) into which a heat transfer tube bundle (120) is inserted and a plurality of grid holes (162) formed between the insertion holes (161).

[0060] The insertion holes (161) are formed in a number corresponding to the number of heat transfer tubes in the heat transfer tube bundle (120), and the grid holes (162) can be formed between the insertion holes (161) while connecting the insertion holes (161).

[0061] A spacer grid (160) can be installed by welding on the inner surface of a straight body (110) to support a heat transfer tube bundle (120). Additionally, the spacer grid (160) can prevent the problem of flow-induced vibration (FIV) that may occur under conditions of high air flow in the heat transfer tube bundle (120), which is formed long in the longitudinal direction through a plurality of grid holes (162).

[0062] Referring to FIG. 8, a support (170) may be installed on one side of the corrugated tube (150) to vertically support the straight body (110). The support (170) can fix the sodium-air heat exchanger (100) by installing and fixing the straight body (110) to the fixing target.

[0064] The embodiments of the present disclosure described above are merely illustrative, and those skilled in the art will readily understand that various modifications and equivalent alternative embodiments are possible therefrom. Therefore, it will be understood that the present disclosure is not limited only to the forms mentioned in the detailed description above. Accordingly, the true technical scope of protection of the present disclosure should be determined by the technical spirit of the appended claims. Furthermore, it should be understood that the present disclosure includes all modifications, equivalents, and substitutions within the spirit and scope of the present disclosure as defined by the claims appended to the present disclosure. Explanation of the symbols

[0066] 10: Sodium 20: Air 100: Sodium-air heat exchanger 110: Intuitive body 120: Heat transfer tube bundle 130: Upper duct 131: Upper duct sodium section 1311: Sodium inlet 132: Upper duct air section 1321: Air outlet 140: Lower duct 141: Lower duct sodium section 1411: Sodium outlet 142: Lower duct air section 1421: Air inlet 150: Corrugated tube 160: Spacer Grid 170: Support

Claims

Claim 1 A sodium-air heat exchanger comprising: a vertically erected tubular body through which air flows; a heat transfer tube bundle arranged longitudinally within the tubular body through which sodium flows; an upper duct installed on the upper part of the tubular body through which sodium flows and air flows; and a lower duct installed on the lower part of the tubular body through which sodium flows and air flows. Claim 2 A sodium-air heat exchanger according to claim 1, wherein sodium flows from the upper side to the lower side in the heat transfer tube bundle and air flows from the lower side to the upper side in the straight tube body so that the sodium and air exchange heat with each other. Claim 3 A sodium-air heat exchanger according to paragraph 2, wherein the upper duct comprises an upper duct sodium section having a sodium inlet formed on the upper side and communicating with the heat transfer tube bundle, and an upper duct air section in which the upper part of the straight body is inserted and installed for a set length and an air outlet is formed on the side. Claim 4 A sodium-air heat exchanger according to paragraph 3, wherein the air outlet is formed to be located above the upper end of the straight body, and the inner wall of the upper duct air section is formed to form a width set on the inner surface of the upper duct air section to form a downward flow path leading to the air outlet. Claim 5 In paragraph 2, the sodium-air heat exchanger comprises a lower duct having a sodium outlet formed on the lower side and communicating with the heat transfer tube bundle, a lower duct sodium section in which the lower part of the straight body is inserted and installed for a set length and an air inlet formed on the side. Claim 6 A sodium-air heat exchanger according to claim 5, wherein the air inlet is formed to be located above the lower end of the straight body, and the inner wall of the lower duct air section is formed to form a width set on the inner surface of the lower duct air section to form an upward flow path leading to the air inlet. Claim 7 A sodium-air heat exchanger according to claim 1, wherein a corrugated tube of a set length is installed around the outer circumference of the straight body. Claim 8 A sodium-air heat exchanger according to claim 1, wherein a plurality of spacer grids are installed at set intervals inside the tubular body to support the heat transfer tube bundles inserted therein. Claim 9 In claim 8, the sodium-air heat exchanger is formed such that the spacer grid is formed with a plurality of insertion holes into which the heat transfer tube bundles are inserted and a plurality of grid holes formed between the insertion holes. Claim 10 A sodium-air heat exchanger according to claim 7, wherein a support is installed on one side of the corrugated tube to vertically support the straight body.

Images