An integrated nuclear reactor primary circuit heat exchanger

Abstract

The present invention relates to an integrated nuclear reactor primary circuit heat exchanger, and belongs to the technical field of nuclear reactors. It comprises an outer cylinder, an intermediate cylinder, an inner cylinder, a spiral baffle and a core. The inner cylinder, the intermediate cylinder and the outer cylinder are sequentially installed between an annular bottom plate and an annular top plate. The core is placed in the inner cylinder. A heat exchange tube is arranged in the cavity between the inner cylinder and the intermediate cylinder. The heat exchange medium in the core and the heat exchange medium in the heat exchange tube constitute a primary circuit of the integrated nuclear reactor. The spiral baffle is welded to the outer wall of the inner cylinder. The primary circuit heat exchanger of the present invention eliminates the dead zone that cannot be utilized between small heat exchangers, increases the pipe layout area of ​​the heat exchange tube, and improves the efficiency of the reactor; the spiral baffle inhibits the accumulation and precipitation of dirt in the shell-side fluid, and increases the service life of the heat exchanger. The heat exchanger increases the effective length of the heat exchange tube, which reduces the equipment cost while improving the heat exchange efficiency of the reactor.

Description

Technical Field

[0001] The invention relates to an integrated nuclear reactor primary circuit heat exchanger. When the reactor is used for heat supply, the primary circuit is a heat exchanger; when the reactor is directly used for power generation, the primary circuit is an evaporator. The invention belongs to the technical field of nuclear reactors. Background Art

[0002] An integrated nuclear reactor integrates heat exchangers, fuel assemblies, control rods and other components in the reactor pressure vessel, and the pressure vessel forms the main body of the primary circuit pressure boundary. The heat exchanger is a heat exchange device that connects and isolates the reactor coolant circuit and the secondary circuit. Previously designed heat exchangers, such as the split U-tube heat exchanger used in the 200MW low-temperature nuclear heating reactor in Nuclear Power Engineering Volume 24, Issue 2, the split straight tube heat exchanger used in the 5MWTHR main heat exchanger in Nuclear Power Engineering Volume 11, Issue 6, the shell-and-tube structure used in the main heat exchanger of the multi-purpose heavy water research reactor in Atomic Energy Science and Technology Volume 33, Issue 1, and the spiral tube evaporator used in the high-temperature gas-cooled reactor, have structures such as Figure 1 and Figure 2 As shown, Figure 1 and Figure 2 In the figure, a is the pressure vessel, b is the heat exchanger, c is the secondary circuit pipe port, and d is the core. As can be seen from the figure, the existing split U-tube heat exchangers, except for the straight tube scheme, have the disadvantages of being difficult to inspect in service, difficult to manufacture, and unable to effectively prevent tube flow vibration. The existing straight tube heat exchangers have low heat exchange efficiency. Therefore, the heat exchanger must be redesigned to solve the problems of in-service inspection, tube flow vibration, and low heat exchange efficiency that cannot be achieved by previous solutions. Summary of the invention

[0003] The purpose of the present invention is to provide an integrated nuclear reactor primary circuit heat exchanger so that the heat exchanger can be inspected in service, effectively prevent tube flow vibration, and provide a better and safer heat exchanger for the integrated nuclear reactor.

[0004] The integrated nuclear reactor primary circuit heat exchanger proposed by the present invention comprises an annular bottom plate, an annular top plate, an outer cylinder, an intermediate cylinder, an inner cylinder, a spiral baffle and a core, wherein the inner cylinder, the intermediate cylinder and the outer cylinder are coaxially installed from inside to outside between the annular bottom plate and the annular top plate in sequence; the core is placed in the inner cylinder, a heat exchange tube is arranged in the cavity between the inner cylinder and the intermediate cylinder, and the heat exchange medium in the core and the heat exchange medium in the heat exchange tube constitute a primary circuit of the integrated nuclear reactor; the spiral baffle is arranged along the outer wall of the inner cylinder The spiral ascending coil is welded on the outer wall of the inner cylinder, and the heat exchange medium in the spiral baffle is connected with the heat exchange medium in the cavity between the inner cylinder and the intermediate cylinder; the cavity between the intermediate cylinder and the outer cylinder is the secondary circuit of the integrated nuclear reactor, and the upper part of the outer cylinder is provided with a secondary circuit inlet pipe and a secondary circuit outlet pipe; the outer cylinder and the pressure vessel cylinder are connected as a whole through an annular top plate and an annular bottom plate, and the boundary of the pressure vessel in the nuclear reactor is used as the boundary of the outer cylinder of the heat exchanger, and the heat exchanger is a part of the reactor pressure vessel.

[0005] The integrated nuclear reactor primary circuit heat exchanger proposed by the present invention has the following advantages:

[0006] 1. The integrated nuclear reactor primary circuit heat exchanger of the present invention replaces multiple small heat exchangers in existing nuclear reactor types such as 5MW THR and 200MW low-temperature nuclear heating reactor with one annular heat exchanger, thereby eliminating the unusable dead zones between the small heat exchangers, increasing the pipe layout area of ​​the heat exchange tubes, and improving the heating efficiency of the reactor.

[0007] 2. The integrated nuclear reactor primary-loop heat exchanger of the present invention uses the boundary of the pressure vessel in the nuclear reactor as the boundary of the outer cylinder of the heat exchanger. The heat exchanger is a part of the reactor pressure vessel and does not require other support and positioning. The secondary-loop inlet and outlet of the heat exchanger extend directly from the outer wall, avoiding the problem that the main heat exchangers of existing nuclear reactors such as 5MW THR and 200MW low-temperature nuclear heating reactors rely on the secondary-loop inlet and outlet for support, and can better ensure the position accuracy of the secondary-loop inlet and outlet. At the same time, it avoids the additional load on the secondary-loop inlet and outlet caused by the weight of the main heat exchanger, saving space and materials for the construction of nuclear reactors and reducing equipment costs.

[0008] 3. The primary heat exchanger of the present invention has the number of annular top plates and annular bottom plates reduced by half compared to the straight tube or shell-and-tube heat exchangers in 5MWTHR and multipurpose heavy water research reactors, reducing the total material and processing costs of the annular top plates and annular bottom plates. At the same time, the secondary circuit chamber in the straight tube or shell-and-tube heat exchanger is omitted in the main heat exchanger, and the secondary circuit inlet and outlet are set on the outer wall. Therefore, compared with the existing structure of setting the secondary circuit inlet and outlet on the top or on the side wall of the secondary circuit chamber in the straight tube or shell-and-tube heat exchanger, a certain height is saved, the effective length of the heat exchange tube is increased, and while improving the heating efficiency of the nuclear heating reactor, more than half of the cost is saved.

[0009] 4. The integrated nuclear reactor primary heat exchanger of the present invention has spiral baffles wound around the outer side of the secondary inner tube to form continuous support for the heat exchanger tube bundle, reducing the vibration induced by the fluid; the spiral baffles are continuous curved surfaces, so that the water in the intermediate loop flows in the form of a spiral plunger, without dead zones, and at the same time improving the heat transfer capacity; the spiral baffle structure can effectively inhibit the accumulation and precipitation of dirt in the shell-side fluid, thereby increasing the service life of the main heat exchanger. Compared with existing heat exchangers, the structure is simple and the flow resistance is reduced. Primary heat exchanger

[0010] 5. The integrated nuclear reactor primary circuit heat exchanger of the present invention can realize in-service inspection of the heat exchanger, and can block the tube for repair when there is a problem with the heat exchange tube. However, it is not easy to realize in-service inspection and block the tube for repair of existing nuclear reactor small heat exchangers such as 5MW THR and 200MW low-temperature nuclear heating reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of the existing 200MW nuclear heating reactor and heat exchanger structure.

[0012] Figure 2 yes Figure 1 Top view of the .

[0013] Figure 3 It is a structural schematic diagram of the integrated nuclear reactor primary circuit heat exchanger proposed by the present invention.

[0014] Figure 4 yes Figure 3 Top view of the .

[0015] Figure 5 This is a schematic diagram of the installation of spiral baffles.

[0016] Figure 1 and Figure 2 In the figure, a is the pressure vessel, b is the heat exchanger, c is the secondary circuit pipe mouth, and d is the core.

[0017] Figure 3 and Figure 4Among them, 1 is an annular bottom plate, 2 is an outer cylinder, 3 is an intermediate cylinder, 4 is a secondary circuit outlet pipe, 5 is a secondary circuit inlet pipe, 6 is a heat exchange tube, 7 is an inner cylinder, 8 is a spiral baffle, 9 is an annular top plate, and 10 is a core.

[0018] Figure 5 In the figure, 11 is a pore. DETAILED DESCRIPTION

[0019] The present invention proposes an integrated nuclear reactor primary circuit heat exchanger, the structure of which is as follows: Figure 3 and Figure 4 As shown, it includes an annular bottom plate 1, an annular top plate 9, an outer cylinder 2, an intermediate cylinder 3, an inner cylinder 7, a spiral baffle 8 and a core 10. The inner cylinder 7, the intermediate cylinder 3 and the outer cylinder 2 are coaxially installed between the annular bottom plate 1 and the annular top plate 9 from the inside to the outside; the core 10 is placed in the inner cylinder 7, and a heat exchange tube 6 is arranged in the cavity between the inner cylinder 7 and the intermediate cylinder 3. The heat exchange medium in the core 10 and the heat exchange medium in the heat exchange tube 6 constitute a primary circuit of the integrated nuclear reactor; the spiral baffle 8 is spirally ascended along the outer wall of the inner cylinder 7 and is welded on the outer wall of the inner cylinder 7, as shown in FIG. Figure 3 As shown in the figure, the heat exchange medium in the spiral baffle 8 is interconnected with the heat exchange medium in the cavity between the inner cylinder 7 and the intermediate cylinder 3; the cavity between the intermediate cylinder 3 and the outer cylinder 2 is the secondary circuit of the integrated nuclear reactor, and the upper part of the outer cylinder 2 is provided with a secondary circuit inlet pipe 5 and a secondary circuit outlet pipe 4; the outer cylinder 2 is connected to the pressure vessel cylinder through an annular top plate 9 and an annular bottom plate 1, and the boundary of the pressure vessel in the nuclear reactor is used as the boundary of the outer cylinder of the heat exchanger, and the heat exchanger is a part of the reactor pressure vessel.

[0020] The working principle and working process of the integrated nuclear reactor primary circuit heat exchanger proposed by the present invention are described in detail below in conjunction with the accompanying drawings:

[0021] In terms of overall structure: the primary heat exchanger adopts an annular tube bundle structure, with a total of one unit, as the middle section of the pressure vessel, and its outer cylinder 2 shares a shell with the pressure vessel; the annular tube bundle is located in the annular space between the intermediate cylinder 3 and the inner cylinder 7; the upper ends of the outer cylinder 2, the intermediate cylinder 3, and the inner cylinder 7 of the heat exchanger are welded to the annular top plate 9; the inner cylinder 7 and the outer cylinder 2 are pressure-bearing cylinders, and the lower ends of the two pressure-bearing cylinders are welded to the annular bottom plate 1; the spiral baffle 8 is coiled and welded inside The outer wall of the cylinder 7; the annular top plate 9, the annular bottom plate 1 and the spiral baffle 8 are processed with the same number of tube holes as the heat exchange tube 6, and the tube holes are evenly distributed along the annular area; the heat exchange tube 6 passes through the tube holes on the annular top plate 9, the spiral baffle 8 and the annular bottom plate 1, and is welded to the annular top plate 9 and the annular bottom plate 1; the secondary circuit inlet pipe 5 is welded to the outer cylinder 2 of the main heat exchanger, and the secondary circuit outlet pipe 4 is welded to the intermediate cylinder 3 (non-pressure cylinder); the secondary circuit inlet and inlet pipes are respectively connected to the secondary circuit system.

[0022] In terms of flow channel design: the main heat exchanger adopts a single straight tube heat transfer surface, with only one annular top plate and one annular bottom plate. There are two flow channels for heat transfer, the inner flow channel inside the heat exchange tube 6 (primary circuit water) and the outer flow channel outside the heat exchange tube 6, on the spiral baffle 8 (intermediate circuit water); the secondary circuit rises around the spiral baffle, and the inner flow channel and the outer flow channel perform countercurrent heat exchange.

[0023] In terms of structure and manufacturing assembly: the heat exchanger adopts a single straight tube structure, and the connection method between the heat exchange tube and the annular top plate and the annular bottom plate is strength welding + strength expansion. The assembly and expansion welding sequence can be determined by the manufacturing unit.

Claims

1. An integrated nuclear reactor primary circuit heat exchanger, characterized in that It comprises an annular bottom plate, an annular top plate, an outer cylinder, an intermediate cylinder, an inner cylinder, a spiral baffle and a core, wherein the inner cylinder, the intermediate cylinder and the outer cylinder are coaxially installed between the annular bottom plate and the annular top plate from the inside to the outside in sequence; the core is placed in the inner cylinder, a heat exchange tube is arranged in the cavity between the inner cylinder and the intermediate cylinder, and the heat exchange medium in the core and the heat exchange medium in the heat exchange tube constitute a primary circuit of the integrated nuclear reactor; the spiral baffle is spirally ascended and coiled along the outer wall of the inner cylinder and welded on the outer wall of the inner cylinder, and the heat exchange medium in the spiral baffle is interconnected with the heat exchange medium in the cavity between the inner cylinder and the intermediate cylinder; the cavity between the intermediate cylinder and the outer cylinder is the secondary circuit of the integrated nuclear reactor, and a secondary circuit inlet pipe and a secondary circuit outlet pipe are arranged on the upper part of the outer cylinder; the outer cylinder is connected to the cylinder of the pressure vessel through the annular top plate and the annular bottom plate, and the boundary of the pressure vessel in the nuclear reactor is used as the boundary of the outer cylinder of the heat exchanger, and the heat exchanger is a part of the reactor pressure vessel.

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