Refueling system and method for a small nuclear power reactor

Abstract

This invention discloses a refueling system and method for a small nuclear power reactor. The system, located within the reactor building, includes a reactor pool, a spent fuel pool, and a fuel transfer channel. The spent fuel pool comprises a spent fuel storage area and other storage areas separated by walls lower than the spent fuel pool itself. The fuel transfer channel is a passage enclosed by walls and extends from the bottom of the spent fuel pool to the reactor pool. During refueling, the water in the reactor pool and spent fuel pool is at the refueling level, which is higher than the walls. The reactor pool is connected to the spent fuel pool via the fuel transfer channel, and the spent fuel storage area is connected to the other storage areas. After refueling, the water in the reactor pool and fuel transfer channel is drained, and the spent fuel pool is drained to the storage level, which is lower than the walls. The reactor pool and spent fuel pool, as well as the spent fuel storage area and other storage areas, are now isolated. This invention improves the reliability of the refueling system.

Description

Technical Field

[0001] This invention relates to the field of nuclear reactor engineering technology, and in particular to a refueling system and refueling method for a small nuclear power reactor. Background Technology

[0002] Nuclear reactors with a power generation capacity of no more than 300MW are called small modular reactors (SMRs). Miniaturization brings advantages such as lower construction costs, wider application range, and often higher safety, making it a key reactor type for development by various countries and nuclear power companies.

[0003] Existing large nuclear power reactors (referred to as "large reactors") all have cylindrical reactor buildings (containments) as a third barrier to prevent radioactive leakage. The reactor building is designed as cylindrical rather than square to withstand the high temperature and pressure inside the building under extreme accidents, while keeping the construction cost at a relatively low level. Because to contain the high temperature and pressure generated by an accident inside the large reactor without damage, the construction cost of a square building is much higher than that of a cylindrical building.

[0004] Small modular reactors (SMRs) are much smaller in scale, and the temperature and pressure inside the reactor building are also much lower than those of large reactors under extreme accident conditions. Therefore, a rectangular reactor building can be considered. The rectangular building structure is more compact, which greatly benefits the flexibility of SMR layout and the economy of SMR construction. In addition, the advantages of SMRs lie in their compact structure and low construction cost. Simply copying the facilities and structure of large reactors to build SMRs would cause them to lose their advantages and competitiveness. The refueling system is an essential system for reactors and occupies a large part of the reactor facilities. Therefore, the refueling system is the key to the design and optimization of SMRs. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address at least one defect of the related technologies mentioned in the background: copying the facilities and structure of large reactors to build small reactors will cause small reactors to lose their advantages and competitiveness. The present invention provides a refueling system and refueling method for small nuclear power reactors.

[0006] The technical solution adopted by the present invention to solve its technical problem is: to construct a refueling system for a small nuclear power reactor, wherein the system is located in the reactor building and includes a reactor pool, a spent fuel pool and a fuel transfer channel.

[0007] The spent fuel pool includes a spent fuel storage area and other item storage areas separated by walls lower than the height of the spent fuel pool;

[0008] The fuel transfer channel is a channel enclosed by the wall and extends from the bottom of the spent fuel pool to the reactor pool;

[0009] During refueling, the water in the reactor pool and the spent fuel pool is at the refueling level, which is higher than the wall. The reactor pool is connected to the spent fuel pool through the fuel transfer channel, and the spent fuel storage area is connected to the other items storage area.

[0010] After refueling is completed, the water in the reactor pool and the fuel transfer channel is drained, the spent fuel pool is drained to the storage level, the storage level is lower than the wall, and the reactor pool and the spent fuel pool, as well as the spent fuel storage area and the other items storage area are separated.

[0011] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the system further includes a fuel transport device that can move within the fuel transfer channel.

[0012] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the fuel transfer channel includes a first channel enclosed by the wall, a second channel extending horizontally from the bottom of the first channel, and a third channel extending vertically from the reactor pool to the second channel.

[0013] The fuel transport device can move within the first channel and the second channel.

[0014] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the height of the second channel is the height at which the fuel can be kept upright during the fuel transport process.

[0015] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the system further includes a sealing cover disposed in the reactor pool for sealing the fuel transfer channel.

[0016] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the system further includes a reactor pool shielding cover for sealing the reactor pool.

[0017] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the system further includes a refueling machine mounted on the reactor pool, a fuel crane mounted on the spent fuel pool, and a traveling crane mounted in the reactor building.

[0018] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the other items storage area includes a waste control rod storage area, a new fuel underwater storage area, a damaged fuel storage area, and a related component storage area.

[0019] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the reactor pool includes a reactor pit, a reactor chamber opened in the reactor pit, a pressure vessel disposed in the reactor chamber, a reactor pit cover plate disposed on the outer periphery of the pressure vessel and sealing the reactor pit, an in-core component storage cavity, an in-core component hoisting tool storage cavity, and a control rod drive shaft storage cavity.

[0020] Preferably, in the refueling system of the small nuclear power reactor of the present invention, the system further includes a multi-functional pool for storing water introduced into the spent fuel pool and the reactor pool during refueling, for safe release in reactor accident conditions, and for cleaning the transport containers.

[0021] The present invention also provides a refueling method for a refueling system of a small nuclear power reactor as described in any of the above claims, comprising the following steps:

[0022] Refueling procedure: Water is injected into the reactor pool, and the water in the reactor pool and the spent fuel pool is at the refueling level. The reactor pool is connected to the spent fuel pool through the fuel transfer channel. The spent fuel storage area is connected to the other items storage area. Spent fuel unloaded from the reactor core in the reactor pool is transferred to the spent fuel storage area through the fuel transfer channel. New fuel lifted from the other items storage area is transferred to the reactor pool through the fuel transfer channel and loaded into the reactor core.

[0023] Refueling completion steps: Drain the water from the reactor pool and the fuel transfer channel, drain the spent fuel pool to the storage level, the storage level is lower than the wall, and the reactor pool and the spent fuel pool, as well as the spent fuel storage area and the other items storage area are separated.

[0024] By implementing this invention, the following beneficial effects are achieved:

[0025] This invention places the spent fuel pool within the reactor building of a small reactor, eliminating the need for a fuel building in a large reactor. Furthermore, the spent fuel pool integrates multiple functional areas, simplifying the structure and layout. Combined with the square building design, the entire building structure can be arranged very compactly, significantly reducing the reactor building volume while still accommodating spent fuel for the entire reactor lifespan. Eliminating the nuclear fuel building, simplifying the structure, and reducing the building size can significantly reduce the overall construction cost of a nuclear power plant.

[0026] This invention integrates the spent fuel storage area and other item storage areas involved in the refueling system into the spent fuel pool and sets up walls. By utilizing changes in liquid level, the connection and isolation between the reactor pool and the spent fuel pool, as well as between the spent fuel storage area and other item storage areas, can be achieved, further simplifying the structure, making the layout more compact, and eliminating the need for gates or valves in the fuel transfer channel, thereby improving the reliability of the entire refueling process system. Attached Figure Description

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

[0028] Figure 1 This is a plan view of the refueling system of the small nuclear power reactor of the present invention;

[0029] Figure 2 This is an elevation view of the refueling system of the small nuclear power reactor of the present invention. Detailed Implementation

[0030] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0031] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0032] In the description of the invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of the invention, unless otherwise stated, "a plurality of" means two or more.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or a chemical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] like Figure 1 and 2 As shown, the first embodiment of the present invention discloses a refueling system for a small nuclear power reactor. The system is located in the reactor building and includes a reactor pool 1, a spent fuel pool 5, and a fuel transfer channel 3.

[0035] The spent fuel pool 5 includes a spent fuel storage area 52 and other item storage areas separated by walls 51 that are lower than the height of the spent fuel pool 5.

[0036] The fuel transfer channel 3 is a channel enclosed by the wall 51 and extends from the bottom of the spent fuel pool 5 to the reactor pool 1.

[0037] During refueling, the water in reactor pool 1 and spent fuel pool 5 is at refueling level A, which is higher than wall 51. Reactor pool 1 is connected to spent fuel pool 5 through fuel transfer channel 3, and spent fuel storage area 52 is connected to other item storage areas.

[0038] After refueling is completed, the water in reactor pool 1 and fuel transfer channel 3 is drained, and spent fuel pool 5 is drained to storage level B. Storage level B is lower than wall 51, and reactor pool 1 and spent fuel pool 5 are separated from each other and spent fuel storage area 52 from other storage areas.

[0039] Specifically, in this embodiment, the system also includes a fuel transport device 6, such as a fuel transport vehicle, that can move within the fuel transfer channel 3. After the refueling is completed and the water in the fuel transfer channel 3 is drained, the fuel transport vehicle and its tracks within the fuel transfer channel 3 can be inspected and maintained.

[0040] In this embodiment, the fuel transfer channel 3 includes a first channel 31 enclosed by a wall 51, a second channel 32 extending horizontally from the bottom of the first channel 31, and a third channel 33 extending vertically from the reactor pool 1 to the second channel 32. The fuel transport device 6 can move within the first channel 31 and the second channel 32. Furthermore, the height of the second channel 32 is the height at which the fuel can remain upright during fuel transport by the fuel transport device 6.

[0041] In this embodiment, the system also includes a sealing cover 4 located in the reactor pool 1 for sealing the fuel transfer channel 3, eliminating the need for a gate or valve in the fuel transfer channel 3. During non-refueling periods, the water level in the fuel transfer channel 3 is below the sealing cover 4 or empty, while the storage liquid level B in the spent fuel pool 5 is below the wall 51. Therefore, even if the sealing cover 4 fails during reactor operation, water from the spent fuel pool 5 will not enter the reactor pool 1 and flood the reactor. Only when the reactor is operating and spent fuel in the spent fuel pool 5 needs to be hoisted will the water level in the spent fuel pool 5 be at the refueling liquid level A, higher than the sealing cover 4, requiring the sealing cover 4 to prevent water from the spent fuel pool 5 from entering the reactor pool 1. Furthermore, under extreme reactor accident conditions, the sealing cover 4 can prevent high-energy water from the reactor pool 1 from entering the spent fuel pool 5, ensuring the safety of spent fuel storage.

[0042] In this embodiment, the system also includes a reactor pool shielding cover 2 for sealing the reactor pool 1. Opening only during core refueling significantly reduces radiation levels within the reactor building during reactor operation, allowing personnel to enter the building and handle fuel in the spent fuel pool 5 while the reactor is running. Furthermore, the design of the reactor pool shielding cover 2 facilitates the integration of the spent fuel pool 5 into the reactor building.

[0043] In this embodiment, the system also includes a loading and unloading machine 7 mounted on the reactor pool 1, a fuel crane 8 mounted on the spent fuel pool 5, and a traveling crane (not shown) mounted inside the reactor building.

[0044] In this embodiment, the spent fuel pool 5 includes at least two spent fuel storage areas 52, the total capacity of which allows for the storage of all spent fuel generated during the entire reactor lifespan. Simultaneously, the two spent fuel storage areas 52 serve as backups for each other. This design allows for the transfer of spent fuel to one storage area during the first half of the reactor's lifespan, while the other storage area is emptied and its fuel racks are maintained and replaced.

[0045] The other storage areas include waste control rod storage area 53, new fuel underwater storage area 54, damaged fuel storage area 55, and related component storage area 56.

[0046] In this embodiment, the reactor pool 1 includes a reactor pit 11, a reactor chamber 12 opened in the reactor pit 11, a pressure vessel 13 disposed in the reactor chamber 12, a reactor pit cover 14 disposed on the outer periphery of the pressure vessel 13 and sealing the reactor pit 11, an in-core component storage cavity 15, an in-core component hoisting tool storage cavity 16, and a control rod drive shaft storage cavity 17.

[0047] In this embodiment, the system also includes a multi-functional pool 9, used to store water introduced into the spent fuel pool 5 and reactor pool 1 during refueling, for safe release in reactor accident conditions, and for cleaning the transport container. The specific cleaning steps are as follows: First, the transport container is transported into the reactor building, hoisted into the multi-functional pool 9 for surface cleaning, then hoisted into the relevant component storage area 56 of the spent fuel pool 5 for spent fuel loading, and after loading, it is hoisted back into the multi-functional pool 9 for surface cleaning. After cleaning, it is transported out of the reactor building.

[0048] In addition, in this embodiment, the system also includes a new fuel inspection area 10a and a new fuel storage area 11a. The new fuel inspection area 10a is used to check the size and integrity of new fuel; incorrect size or excessive bending will affect stacking.

[0049] The second embodiment of the present invention discloses a refueling method for the refueling system of the small nuclear power reactor described in the first embodiment, comprising the following steps:

[0050] Refueling procedure: Water is injected into reactor pool 1, and the water in reactor pool 1 and spent fuel pool 5 is at refueling level A. Reactor pool 1 is connected to spent fuel pool 5 through fuel transfer channel 3. Spent fuel storage area 52 is connected to other storage areas. Spent fuel unloaded from the reactor core in reactor pool 1 is transferred to spent fuel storage area 52 through fuel transfer channel 3. New fuel lifted from other storage areas is transferred to reactor pool 1 through fuel transfer channel 3 and loaded into the reactor core.

[0051] Refueling completion steps: Drain the water from reactor pool 1 and fuel transfer channel 3, drain spent fuel pool 5 to storage level B, storage level B is lower than wall 51, reactor pool 1 and spent fuel pool 5 are separated from each other and spent fuel storage area 52 is separated from other item storage areas.

[0052] Specifically, the refueling procedure is as follows: First, open the reactor pool shielding cover 2, then open the sealing cover 4 of the fuel transfer channel 3 in the reactor pool 1. Next, use the overhead crane in the reactor building to lift the reactor pressure vessel top cover 131 to a temporary storage location within the building. During the lifting of the pressure vessel top cover 131, water is injected into the previously dry reactor pool 1. The area below the reactor pit cover 14 remains dry. The water level in the reactor pool 1 and the spent fuel pool 5 is maintained at refueling level A, ensuring sufficient shielding water coverage for the fuel throughout the transfer process. The reactor pool 1 is connected to the spent fuel pool 5 via the fuel transfer channel 3, and the spent fuel storage area 52 is connected to other storage areas. Then, use the overhead crane in the reactor building to lift the reactor internals, control rod drive shafts, and reactor internals lifting equipment to the reactor internals storage chamber 15, reactor internals lifting equipment storage chamber 16, and control rod drive shaft storage chamber 17 within the reactor pool 1 for storage. The spent fuel is then unloaded from the reactor core using the loading and unloading machine 7 mounted on the reactor pool 1 and loaded into the fuel transport device 6 in the fuel transfer channel 3. The fuel transport device 6 travels in the fuel transfer channel 3 to the side of the spent fuel pool 5, where the fuel crane 8 on the spent fuel pool 5 lifts the spent fuel from the fuel transport device 6, passes over the wall 51 in the spent fuel pool 5 of the fuel transfer channel 3, and loads it into the spent fuel storage area 52 for storage.

[0053] The new fuel is loaded by using the fuel crane 8 on the spent fuel pool 5 to lift the new fuel underwater storage area 54 in the spent fuel pool 5 to the fuel transport device 6 in the fuel transfer channel 3. The fuel transport device 6 travels in the fuel transfer channel 3 to the reactor pool 1 side, and then the new fuel is loaded into the reactor core by the loading and unloading machine 7 on the reactor pool 1.

[0054] By implementing this invention, the following beneficial effects are achieved:

[0055] This invention places the spent fuel pool within the reactor building of a small reactor, eliminating the need for a fuel building in a large reactor. Furthermore, the spent fuel pool integrates multiple functional areas, simplifying the structure and layout. Combined with the square building design, the entire building structure can be arranged very compactly, significantly reducing the reactor building volume while still accommodating spent fuel for the entire reactor lifespan. Eliminating the nuclear fuel building, simplifying the structure, and reducing the building size can significantly reduce the overall construction cost of a nuclear power plant.

[0056] This invention integrates the spent fuel storage area and other item storage areas involved in the refueling system into the spent fuel pool and sets up walls. By utilizing changes in liquid level, the connection and isolation between the reactor pool and the spent fuel pool, as well as between the spent fuel storage area and other item storage areas, can be achieved, further simplifying the structure, making the layout more compact, and eliminating the need for gates or valves in the fuel transfer channel, thereby improving the reliability of the entire refueling process system.

[0057] It is understood that the above embodiments only illustrate some implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that for those skilled in the art, without departing from the concept of the present invention, the above embodiments or technical features can be freely combined, and several modifications and improvements can be made. These all fall within the protection scope of the present invention. That is, the embodiments described "in some embodiments" can be freely combined with any of the embodiments above and below. Therefore, all equivalent transformations and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A refueling system for a small nuclear power reactor, characterized in that, The system is located inside the reactor building and includes a reactor pool (1), a spent fuel pool (5), a fuel transfer channel (3), and a sealing cover (4). The spent fuel pool (5) includes a spent fuel storage area (52) and other item storage areas separated by a wall (51) with a height lower than that of the spent fuel pool (5); The fuel transfer channel (3) is a channel enclosed by the wall (51) and extends from the bottom of the spent fuel pool (5) to the reactor pool (1); The sealing cover (4) is located in the reactor pool (1) and is used to seal the fuel transfer channel (3). During refueling, the water in the reactor pool (1) and the spent fuel pool (5) is at refueling level A, which is higher than the wall (51). The sealing cover (4) of the fuel transfer channel (3) in the reactor pool (1) is opened. The reactor pool (1) is connected to the spent fuel pool (5) through the fuel transfer channel (3). The spent fuel storage area (52) is connected to the other items storage area. After the refueling is completed, the water in the reactor pool (1) and the fuel transfer channel (3) is drained, the spent fuel pool (5) is drained to the storage level B, the storage level B is lower than the wall (51), and the reactor pool (1) and the spent fuel pool (5) and the spent fuel storage area (52) are separated from the other items storage area.

2. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The system also includes a fuel transport device (6) that can move within the fuel transfer channel (3).

3. The refueling system for a small nuclear power reactor according to claim 2, characterized in that, The fuel transfer channel (3) includes a first channel (31) enclosed by the wall (51), a second channel (32) extending horizontally from the bottom of the first channel (31), and a third channel (33) extending vertically from the reactor pool (1) to the second channel (32). The fuel transport device (6) can move within the first channel (31) and the second channel (32).

4. The refueling system for a small nuclear power reactor according to claim 3, characterized in that, The height of the second channel (32) is the height at which the fuel can be kept upright during the fuel transport process of the fuel transport device (6).

5. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The system also includes a reactor pool shielding cover (2) for sealing the reactor pool (1).

6. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The system also includes a loading and unloading machine (7) mounted on the reactor pool (1), a fuel crane (8) mounted on the spent fuel pool (5), and a traveling crane mounted in the reactor building.

7. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The other items storage areas include a waste control rod storage area (53), a new fuel underwater storage area (54), a damaged fuel storage area (55), and a related component storage area (56).

8. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The reactor pool (1) includes a reactor pit (11), a reactor chamber (12) opened in the reactor pit (11), a pressure vessel (13) located in the reactor chamber (12), a reactor pit cover (14) located on the outer periphery of the pressure vessel (13) and sealing the reactor pit (11), an in-core component storage chamber (15), an in-core component hoisting tool storage chamber (16), and a control rod drive shaft storage chamber (17).

9. The refueling system for a small nuclear power reactor according to claim 1, characterized in that, The system also includes a multi-functional pool (9) for storing water introduced into the spent fuel pool (5) and the reactor pool (1) during refueling, for safe release in reactor accident conditions, and for cleaning transport containers.

10. A refueling method for a refueling system of a small nuclear power reactor according to any one of claims 1-9, characterized in that, Includes the following steps: Refueling procedure: Water is injected into the reactor pool (1), and the water in the reactor pool (1) and the spent fuel pool (5) is at the refueling level A. The sealing cover (4) of the fuel transfer channel (3) in the reactor pool (1) is opened. The reactor pool (1) is connected to the spent fuel pool (5) through the fuel transfer channel (3). The spent fuel storage area (52) is connected to the other items storage area. Spent fuel unloaded from the reactor core of the reactor pool (1) is transferred to the spent fuel storage area (52) via the fuel transfer channel (3); new fuel lifted from the other items storage area is transferred to the reactor pool (1) via the fuel transfer channel (3) and loaded into the reactor core; Refueling completion steps: drain the water from the reactor pool (1) and the fuel transfer channel (3), drain the spent fuel pool (5) to storage level B, the storage level B is lower than the wall (51), and the reactor pool (1) and the spent fuel pool (5) are separated from each other and the spent fuel storage area (52) is separated from the other items storage area.

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