Refueling water tank in high-position containment, arrangement method of refueling water tank and reactor building

Abstract

The invention provides a refueling water tank in a high-position containment, an arrangement method thereof and a reactor workshop.The arrangement method comprises the steps that the lower space of the containment is divided into a first area and a second area, the first area is a compartment where a reactor coolant system is located and a compartment directly communicated with the first area, and the first area and the second area are separated in a sealed mode; the refueling water tank is arranged in the containment, and the bottom of the refueling water tank is higher than the reactor core of the reactor, so that water in the refueling water tank is injected into the first area under the action of gravity after the water loss accident occurs; the volume of the refueling water tank is larger than the water amount needed in the first submerging stage. Compared with the prior art, the scheme has the advantages that the volume of water required for submerging the containment is reduced through a partition submerging strategy, the refueling water tank is arranged at the high position in the containment under the condition that a reactor coolant system is in a three-loop overall layout, and the inherent safety level of a nuclear power plant is synchronously improved while the passive safety injection function is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nuclear power technology, and in particular to a high-position in-containment refueling water storage tank and a layout method thereof, and a reactor building. BACKGROUND

[0002] The refueling water storage tank is a core safety structure of the nuclear reactor refueling operation and the emergency core cooling system. Its main functions are: under normal refueling conditions, by providing sufficient borated water for the reactor refueling pool, it ensures that sufficient radiation shielding water depth is maintained during refueling operation; under emergency conditions such as loss of coolant accident (LOCA), it serves as the initial water source of the emergency core cooling system (ECCS) and performs the safety injection function to timely lead out the residual heat of the reactor core and effectively alleviate the consequences of the accident.

[0003] In the iteration process of nuclear power technology, the layout method of the refueling water storage tank continues to evolve. The second-generation pressurized water reactor technology adopts an out-of-containment refueling water storage tank design, and realizes a double water source switching mechanism (first out-of-containment water tank and then containment sump) through a safety injection pump. This scheme has the risk of switching logic failure and relies on the operation of active equipment. The third-generation active technology places the refueling water storage tank inside the containment bottom, i.e., the in-containment refueling water storage tank (IRWST), forming a closed cooling cycle: the safety injection pump takes water from the IRWST → injects into the reactor core → breaks out → gravity returns to the IRWST. Although the switching risk is reduced, it still relies on the operation of active pumps. The third-generation passive technology adopts a high-position IRWST, which is driven by gravity: after the primary loop is depressurized, it automatically injects water → cools the reactor core → submerges the containment → passive recirculation long-term cooling. This scheme completely eliminates the dependence on external energy, but faces the contradiction between large-capacity refueling water storage tank and limited containment space.

[0004] Therefore, under the three-loop layout of the reactor cooling system (RCS), the current layout of the in-containment refueling water storage tank relies on the operation of active pumps. SUMMARY

[0005] The present application provides a high-position in-containment refueling water storage tank and a layout method thereof, and a reactor building, to solve the technical problem that the current layout of the in-containment refueling water storage tank does not have passive injection.

[0006] The present application provides a high-position in-containment refueling water storage tank and a layout method thereof, comprising:

[0007] The lower space of the containment is divided into a first region and a second region, the first region is a compartment where the reactor coolant system is located and a compartment directly connected thereto, and the first region and the second region are sealed and separated;

[0008] The refueling water tank is arranged in the containment vessel, and a bottom of the refueling water tank is higher than a core of the reactor, so that water in the refueling water tank is injected into the first region by gravity after a loss of coolant accident occurs;

[0009] The first submerging stage is a first submerging stage, and a volume of the refueling water tank is greater than a water amount required in the first submerging stage.

[0010] In an embodiment of the present application, a recirculation filter screen is arranged in the first region, and the injection system takes water through the recirculation filter screen and continuously cools the core of the reactor after the first submerging stage is completed, which is a containment vessel recirculation stage.

[0011] In an embodiment of the present application, in the containment vessel recirculation stage, if the first region leaks and the liquid level drops, a water supplement measure is taken to supplement water to the first region to compensate for the amount of water leaked from the first region and to match the liquid level of the first region with the heat conduction requirement of the core of the reactor.

[0012] In an embodiment of the present application, the water supplement measure is taken after 72 hours of the loss of coolant accident.

[0013] In an embodiment of the present application, the water supplement measure is selected from active water supplement and passive water supplement.

[0014] In an embodiment of the present application, in a process in which the water supplement measure is continuously taken, the second region is filled with water and submerged, the second submerging stage is a second submerging stage, if the liquid levels of the first region and the second region are the same and the liquid level of the first region meets the heat conduction requirement of the core, the water supplement measure is stopped, and the recirculation filter screen is used to continuously take water and cool the core of the reactor.

[0015] In an embodiment of the present application, the first region and the second region are sealed and separated by a water-tight structure, and the second region is located at the periphery of the first region.

[0016] In an embodiment of the present application, the refueling water tank and a loop steam generator compartment are arranged, and a maintenance passage is reserved between the refueling water tank and the containment vessel.

[0017] In an embodiment of the present application, the refueling water tank adopts a concrete steel covering structure, and the overall height of the refueling water tank is determined according to the volume of the water amount in the first submerging stage.

[0018] In an embodiment of the present application, the refueling water tank, a loop steam generator and a main pump standby compartment form an integral module, and are integrally hoisted after being prefabricated in a factory.

[0019] In an embodiment of the present application, the automatic depressurization system bubbler of the internal reactor coolant system of the refueling water storage tank is integrated to ensure the discharge requirement of the automatic depressurization system of the reactor.

[0020] The present application also provides a refueling water storage tank in a high containment, which is obtained by the arrangement method described above.

[0021] The present application also provides a reactor building, comprising:

[0022] A containment, a lower space of the containment is divided into a first area and a second area, the first area is a compartment where the reactor coolant system is located and a directly connected compartment, the first area and the second area are sealed and separated;

[0023] A refueling water storage tank, which is located in the containment, a bottom of the refueling water storage tank is higher than a core of the reactor, the refueling water storage tank is used to inject water in the refueling water storage tank into the first area by gravity after a loss of coolant accident occurs;

[0024] The volume of the refueling water storage tank is greater than the water amount required in the first flooding stage.

[0025] The present application has the following advantages: the refueling water storage tank and the arrangement method thereof are proposed, the first area and the second area are divided in the containment, the flooding process of the reactor core in the containment after the loss of coolant accident is optimized, the water amount required for flooding the reactor core is reduced, the water storage amount of the refueling water storage tank is simultaneously reduced, the refueling water storage tank is arranged in the containment, the refueling water storage tank can passively inject water into the reactor core by gravity, the arrangement of the refueling water storage tank is economical and constructible. Compared with the prior art, the volume of the water amount required for flooding the containment is reduced by the zoning flooding strategy, the refueling water storage tank is arranged in the high containment, the passive safety injection function is realized, and the inherent safety level of the nuclear power plant is simultaneously improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] The drawings incorporated by reference in the specification and forming a part thereof, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application. It is clear that the drawings described below are only some embodiments of the present application, and other drawings can be obtained according to these drawings without creative labor for those skilled in the art.

[0027] In the drawings:

[0028] Fig. 1 It is a plane schematic view of a refueling water storage tank in a high containment according to an embodiment of the present application.

[0029] Fig. 2 A high-level in-containment refueling water storage tank is shown as an example of the present application.

[0030] Reference signs are as follows:

[0031] High-level water tank 1, first area 2, second area 3, maintenance passage 4, refueling water tank 5, one-loop steam generator. DETAILED DESCRIPTION

[0032] The present application is described below by way of specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure. The present application can also be implemented or applied by other different embodiments, and various modifications or changes can be made to the details in the specification based on different views and applications without departing from the spirit of the present application. The following embodiments and features in the embodiments can be combined with each other without conflict.

[0033] It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present application, and the drawings only show the components related to the present application, not the number, shape and size of the components when actually implemented. The actual implementation of each component may be a random change, and the component layout pattern may be more complex.

[0034] In the following description, a large number of details are discussed to provide a more thorough explanation of the embodiments of the present application, however, it is obvious to those skilled in the art that the embodiments of the present application can be implemented without these specific details, and in other embodiments, well-known structures and devices are shown in the form of block diagrams rather than in the form of details to avoid making the embodiments of the present application difficult to understand.

[0035] The present application is a high-level in-containment refueling water tank and its arrangement method, and a reactor building, in combination with Figs. 1-2 The high-level in-containment refueling water tank and its arrangement method include:

[0036] The lower space of the containment 1 is divided into a first area 2 and a second area 3, the first area 2 is a compartment where the reactor coolant system is located and a directly connected compartment, and the first area 2 and the second area 3 are sealed and separated;

[0037] The refueling water tank 5 is arranged in the containment 1, and the bottom of the refueling water tank 5 is higher than the core of the reactor, so that after a loss of coolant accident occurs, water in the refueling water tank 5 is injected into the first area 2 by gravity;

[0038] The first area 2 is submerged in a first submerging stage, and the volume of the refueling water tank 5 is greater than the water required in the first submerging stage.

[0039] In the embodiment, the reactor containment 1 is arranged with a reactor coolant system, and the overall layout of the reactor coolant system determines the main layout features of the reactor building. The existing reactor coolant system generally includes two-loop, three-loop and four-loop structures, and different loop structures have different influences on the layout of the building. In the embodiment, a three-loop structure is adopted, including a one-loop main equipment compartment, a two-loop main equipment compartment and a three-loop main equipment compartment, which are arranged around the reactor and extended through as needed according to the design. The reactor coolant system needs to be provided with an automatic depressurization system (ADS), and when the ADS is in action, the one-loop steam (or two-phase flow) discharged by the ADS has a large flow rate, and generally needs to be provided with a pool for containing and cooling, and at the same time, retaining radioactive substances discharged from the one-loop. In the scheme, the reactor containment is integrated with the reactor coolant system automatic depressurization system bubbler inside the refueling water tank, to ensure the discharge requirements of the ADS.

[0040] The scheme optimizes the submerging process of the reactor in the reactor containment 1, reduces the water required for submerging, and realizes the arrangement of the high-level refueling water tank 5 in the reactor containment 1, so that the capacity of the refueling water tank 5 matches the water required for the first stage submerging of the reactor containment 1 under the three-loop reactor coolant system layout. The IRWST is arranged at a high position in the reactor containment 1 under the three-loop RCS overall layout, which realizes the passive injection function and at the same time improves the inherent safety level of the nuclear power plant. The capacity of the IRWST can meet the heat sink capacity requirement of the PRHR HX of the passive residual heat removal system, and the selection of the residual heat removal system is no longer limited.

[0041] Specifically, the reactor containment 1 is divided into a first area 2 and a second area 3. The first area 2 is the compartment where the reactor coolant system is located and the compartments directly connected thereto, i.e. the compartment where the reactor coolant system is located and the adjacent compartments directly connected with the reactor coolant system. The second area 3 is the area below the reactor containment 1 except the first area 2. The submerging process of the reactor core in the reactor containment 1 after a loss of coolant accident only needs to go through the first submerging stage, which reduces the water required for submerging the reactor core and at the same time reduces the water storage capacity of the refueling water tank 5. The refueling water tank 5 is arranged in the reactor containment 1, which ensures that the refueling water tank 5 can passively inject water into the reactor core by gravity, and at the same time, the arrangement of the refueling water tank 5 is economical and buildable.

[0042] In some embodiments, a recirculation filter is placed in the first region 2. After the first flooding phase is complete, the injection system draws water through the recirculation filter and continues to cool the reactor core. This constitutes the recirculation phase of containment 1. This strategy effectively reduces the water demand of the IRWST, making it technically feasible to place the IRWST high in the containment 1.

[0043] In some embodiments, during the recycling stage of the containment vessel 1, if leakage occurs in the first area 2 and causes the liquid level to drop, water replenishment measures are taken to replenish water to the first area 2 to compensate for the leakage of water in the first area 2 and to match the water level of the first area 2 with the core thermal conductivity requirements of the reactor.

[0044] Specifically, if a leak occurs in the first area 2, the water in the first area 2 will flow to the second area 3, and the water depth in the first area 2 will decrease. As the leak continues, the water depth above the recirculation filter gradually becomes unable to drive the injection system to draw water from the recirculation filter and inject it into the core in a passive manner. The containment vessel 1 cannot recirculate, and the core heat extraction requirement cannot be met. At this time, in order to keep the containment vessel 1 recirculating, water can be added to the first area 2 through water replenishment measures. Water replenishment measures can be implemented through various means, as long as it can ensure that water is added to the first area 2. Water replenishment measures use external water sources for water replenishment, and the amount of water compensated by the water replenishment measures in the first area 2 must be greater than the amount of leakage from the first area 2. By setting up water replenishment measures, the liquid level in the first area 2 can be maintained for a long period after the accident, ensuring the long-term heat extraction requirement of the core.

[0045] In some embodiments, the water replenishment measures are performed 72 hours after the LOCA. This operation, performed 72 hours after the accident, significantly reduces the temperature and pressure inside the containment vessel 1, significantly reducing the design challenges for the water replenishment system. Furthermore, since the hydrogen concentration inside the containment vessel 1 is below the explosion limit during the water replenishment operation, this design also eliminates the risk of hydrogen leakage.

[0046] In some embodiments, the water replenishment measure is active water replenishment or passive water replenishment, and water replenishment is used to compensate for leakage in the first region 2 to maintain its water level matching the core heat conduction requirement.

[0047] In some embodiments, the second area 3 enters water and is flooded, and flooding the second area 3 is the second flooding stage; if the water levels of the first area 2 and the second area 3 are the same and the water level of the first area 2 meets the core heat conduction requirement, the water replenishment measure is stopped, and the recycling network is continued to be used to take water to continuously cool the reactor core.

[0048] Specifically, in the second flooding stage, the leakage and water replenishment of the first region 2 continue, and finally the water levels of the first region 2 and the second region 3 are balanced, and the leakage no longer occurs. After the completion of the second flooding stage, the water replenishment measure outside the containment 1 can be cancelled, and the passive recirculation of the containment 1 can be long-term continued.

[0049] In some embodiments, the first region 2 and the second region 3 are sealed and separated by a watertight structure, and the second region 3 is located at the periphery of the first region 2. For example, Fig. 2 As shown, by the watertight structure, it can be better ensured that after the loss of coolant accident occurs, the reactor core can be flooded by only injecting water into the first region 2. The watertight structure can be an existing structure that can be sealed and separated, such as a sealing structure for preventing water from entering the ship body or a sealing structure for limiting the spread of water in the ship after the ship is flooded. The second region 3 is located at the periphery of the first region 2 and wraps the first region 2, so that after the first region 2 leaks, water is only leaked to the second region 3, and the residual heat of the core can be discharged under the water replenishment measure.

[0050] In some embodiments, the refueling water tank 5 and a loop steam generator compartment are arranged, and a maintenance access 4 is reserved between the refueling water tank 5 and the containment 1. For example, Fig. 1 As shown, the three-loop reactor coolant system is more complex in structure, and it is more difficult to connect the refueling water tank in the containment. In the present scheme, after the volume of the refueling water tank 5 is reduced as much as possible, the refueling water tank 5 is arranged in the space between the loop steam generator and the containment 1, and the shape of the refueling water tank 5 can be designed according to the structure of this region, so that the refueling water tank 5 is more reasonable and practical in the containment 1. The maintenance access 4 is reserved between the refueling water tank 5 and the containment 1, so that the refueling water tank 5 can be conveniently maintained.

[0051] In some embodiments, the refueling water tank 5 adopts a concrete steel covering structure, and the overall height of the refueling water tank 5 is determined according to the water volume of the first flooding stage. In the present scheme, the cross-sectional structure of the refueling water tank 5 needs to be designed according to the space between the loop steam generator and the containment 1. In order to ensure that the refueling water tank 5 has sufficient required water volume, the height of the refueling water tank 5 needs to be determined according to the water volume of the first flooding stage.

[0052] In some embodiments, the refueling water tank 5, the loop steam generator, and the main pump standby compartment form an integral module, which is pre-fabricated and hoisted as a whole. This setting can improve the construction efficiency.

[0053] In some embodiments, the refueling water tank 5 is internally integrated with a reactor coolant system automatic pressure relief system bubbler to ensure the discharge requirement of the reactor automatic pressure relief system.

[0054] In some embodiments, the present application also provides a high-position in-containment refueling water storage tank, which is arranged in the containment 1 by the arrangement method in the above embodiments, as shown in Fig. 1 and Fig. 2 .

[0055] In some embodiments, the present application also provides a reactor building, comprising:

[0056] a containment, a lower space of the containment is divided into a first area 2 and a second area 3, the first area 2 is a compartment where a reactor coolant system is located and a directly connected compartment, and a sealing partition is arranged between the first area 2 and the second area 3;

[0057] a refueling water storage tank 5, which is located in the containment, a bottom of the refueling water storage tank 5 is higher than a reactor core, and the refueling water storage tank 5 is used to inject water in the refueling water storage tank 5 into the first area 2 by gravity after a loss of coolant accident occurs;

[0058] wherein a volume of the refueling water storage tank 5 is greater than a water amount required in the first flooding stage.

[0059] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A method for arranging a refueling water tank in an upper containment vessel, characterized by: Dividing the lower space of the containment vessel into a first area and a second area, wherein the first area is a compartment where the reactor coolant system is located and a compartment directly connected thereto, and the first area and the second area are sealed and separated; Arranging a refueling water tank in the containment vessel, with the bottom of the refueling water tank being higher than the core of the reactor, so that after a loss of coolant accident occurs, water in the refueling water tank can be injected into the first region by gravity; Wherein, flooding the first area is a first flooding stage, and the volume of the refueling water tank is greater than the water volume required for the first flooding stage.

2. The method for arranging a refueling water tank in an upper containment vessel according to claim 1, characterized in that: The recirculation filter is arranged in the first area. After the first flooding stage is completed, the injection system takes water through the recirculation filter and continuously cools the reactor core. This is the containment recirculation stage.

3. The method for arranging a refueling water tank in an upper containment vessel according to claim 2, characterized in that: During the containment recirculation phase, if leakage occurs in the first area and causes the liquid level to drop, water replenishment measures are taken to replenish water to the first area to compensate for the leaked water in the first area and to match the water level in the first area with the core heat conduction requirement of the reactor.

4. The method for arranging a refueling water tank in an upper containment vessel according to claim 3, characterized in that: The water replenishment measures are carried out 72 hours after the water loss accident.

5. The method for arranging a refueling water tank in an upper containment vessel according to claim 3, characterized in that: The water replenishment measure is selected as active water replenishment or passive water replenishment.

6. The method for arranging a refueling water tank in an upper containment vessel according to claim 3, characterized in that: During the ongoing water replenishment measures, water enters the second area and is flooded, and the flooding of the second area is the second flooding stage; if the water levels of the first area and the second area are the same and the water level of the first area meets the core heat conduction requirements, the water replenishment measures are stopped, and the recycling network is continued to be used to draw water to continuously cool the reactor core.

7. The method for arranging a refueling water tank in an upper containment vessel according to any one of claims 1 to 6, characterized in that: The first area and the second area are sealed and separated by a watertight structure, and the second area is located outside the first area.

8. The method for arranging a refueling water tank in an upper containment vessel according to any one of claims 1 to 6, characterized in that: The refueling water tank and a loop steam generator compartment are arranged, and an inspection passage is reserved between the refueling water tank and the containment shell.

9. The method for arranging a refueling water tank in an upper containment vessel according to any one of claims 1 to 6, characterized in that: The refueling water tank adopts a concrete steel cladding structure, and the overall height of the refueling water tank is determined according to the water volume in the first flooding stage.

10. The method for arranging a refueling water tank in an upper containment vessel according to any one of claims 1 to 6, characterized in that: The refueling water tank, a loop steam generator, and a main pump standby compartment form an integral module, which is prefabricated in a factory and then hoisted as a whole.

11. The method for arranging a refueling water tank in an upper containment vessel according to any one of claims 1 to 6, characterized in that: The refueling water tank is internally integrated with a bubbler of the automatic pressure relief system of the reactor coolant system to ensure the discharge requirements of the reactor automatic pressure relief system.

12. A refueling water tank in a high-level containment vessel, characterized by: The method is obtained by the arrangement method described in any one of claims 1 to 11.

13. A reactor building, characterized in that: include: a containment vessel, wherein the lower space of the containment vessel is divided into a first area and a second area, wherein the first area is a compartment where the reactor coolant system is located and a compartment directly connected thereto, and the first area and the second area are sealed and separated; a refueling water tank, the refueling water tank being located in the containment vessel, the bottom of the refueling water tank being higher than the core of the reactor, and being used to inject water in the refueling water tank into the first region by gravity after a loss of coolant accident occurs; The volume of the refueling water tank is greater than the amount of water required in the first flooding stage.

Images