Long-term passive cooling system of compact small reactor

Abstract

The invention provides a long-term passive cooling system of a compact small reactor, which is characterized in that a reactor and steam generators are arranged in a containment, the steam generators are connected with the reactor, and each steam generator is provided with a secondary side residual heat removal system; the liquid storage chamber is mounted on the outer wall surface of the containment in a surrounding manner; the passive heat exchanger is arranged in the liquid storage chamber and is connected with a secondary side residual heat removal system of the corresponding steam generator, so that steam of the steam generator enters the passive heat exchanger for heat exchange; the plurality of passive heat pipes are mounted on the wall surface of the containment in a penetrating manner and are used for guiding heat in the containment to the liquid storage chamber. The secondary side waste heat removal system is arranged on the secondary side of the steam generator and used for relieving non-loss-of-water accidents, short-term and long-term reactor core cooling is achieved outside the containment through the passive heat exchanger combining water cooling and air cooling, the peak pressure of the containment after the accidents is effectively reduced, long-term passive heat carrying is achieved, and the unit operation safety is improved.

Description

Technical Field

[0001] The present invention relates to the field of small nuclear reactors, and in particular to a long-term passive cooling system for compact small reactors. Background Art

[0002] Among existing technologies, nuclear energy, as a safe, clean, economical, and stable energy source, is a crucial component of my country's efforts to build a clean, low-carbon, safe, and efficient energy system. While my country's nuclear power industry is experiencing rapid growth, safety remains paramount. Safety is not only fully considered in design, but also strictly enforced during the operation of nuclear power units to ensure they remain in a safe state. The third-generation passive large-scale advanced pressurized water reactor (PWR) will become the primary reactor type for China's nuclear power industry. By adopting a passive safety concept, it will simplify the system and improve safety and economic efficiency.

[0003] In recent years, investment in the research and development of small reactors has been increasing both domestically and internationally, driven by their inherent safety, wide application, flexible deployment, and low investment. The development of small reactors places increasing emphasis on safety, advancement, and affordability, with the continuous introduction of new processes, materials, and technologies, and the thorough demonstration of their engineering feasibility, to ensure safer, more economical, and reliable operation.

[0004] Small reactors employ a passive safety design concept, ensuring their inherent safety. Due to their low power, small reactors generate less decay heat in the core after an accident, requiring far less heat removal and for a shorter duration than large reactors.

[0005] If an advanced long-term passive cooling system can be designed to cope with core cooling after non-LOCA accidents, as well as core cooling and containment cooling after LOCA accidents, and can achieve long-term passive heating, the pressure difference between the inside and outside of the containment will be greatly reduced, the driving force for the leakage of fission products to the outside of the containment will be reduced, the integrity of the containment will be ensured, and the safety of unit operation will be greatly improved.

[0006] In view of this, the inventors of the present application have designed a long-term passive cooling system for a compact small reactor in order to overcome the above technical problems. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the existing technology that small and medium-sized reactors adopt passive safety design, which requires design to deal with core cooling after non-loss of coolant accidents, as well as core cooling and containment cooling after loss of coolant accidents, and provide a long-term passive cooling system for compact small reactors.

[0008] The present invention solves the above technical problems through the following technical solutions:

[0009] A long-term passive cooling system for a compact small reactor is characterized in that the long-term passive cooling system comprises:

[0010] A containment vessel, a reactor, and at least one steam generator, wherein the reactor and the steam generator are installed in the containment vessel, the steam generator is connected to the reactor, and each steam generator is provided with a secondary side waste heat removal system;

[0011] a liquid storage chamber, the liquid storage chamber being circumferentially mounted on the outer wall of the containment vessel;

[0012] at least one passive heat exchanger, the passive heat exchanger being arranged in the liquid storage chamber and connected to the secondary side waste heat removal system of the corresponding steam generator, so that steam from the steam generator enters the passive heat exchanger for heat exchange;

[0013] A plurality of passive heat pipes are installed through the wall of the containment shell and are used to conduct heat in the containment shell to the liquid storage chamber.

[0014] According to one embodiment of the present invention, the secondary side waste heat removal system includes an inlet pipe, an inlet isolation valve, an outlet pipe and an outlet isolation valve, the inlet pipe is connected between the outlet end of the steam generator and the inlet end of the passive heat exchanger, the outlet pipe is connected between the outlet end of the passive heat exchanger and the outlet end of the steam generator, the inlet isolation valve is installed on the inlet pipe, and the outlet isolation valve is installed on the outlet pipe.

[0015] According to one embodiment of the present invention, the long-term passive cooling system includes a plurality of passive heat exchangers, which are connected in series and then connected between the inlet pipe and the outlet pipe.

[0016] According to one embodiment of the present invention, the liquid storage chamber is filled with cooling liquid.

[0017] According to one embodiment of the present invention, the passive heat exchanger is immersed in the cooling liquid in the liquid storage chamber.

[0018] According to one embodiment of the present invention, a balancing plate extending from top to bottom is provided in the liquid storage chamber, at least one cooling air inlet is provided on the outer wall of the liquid storage chamber, and at least one balancing air inlet is provided on the balancing plate. External cooling air enters the first chamber between the balancing plate and the outer wall of the liquid storage chamber through the cooling air inlet, and then enters the second chamber between the balancing plate and the containment shell through the balancing air inlet, for cooling the passive heat exchanger.

[0019] According to one embodiment of the present invention, the outer side wall of the liquid storage chamber is a shielding wall.

[0020] According to an embodiment of the present invention, a plurality of balancing air inlets are provided on the balancing plate, and the balancing air inlets are arranged at intervals from each other.

[0021] According to one embodiment of the present invention, each of the passive heat exchangers is located at the air outlet side of the corresponding balanced air inlet.

[0022] According to one embodiment of the present invention, an outlet is provided at the upper portion of the containment vessel for discharging heat from the liquid storage chamber.

[0023] The positive progress effect of the present invention is:

[0024] The long-term passive cooling system for a compact small reactor of the present invention incorporates a secondary side residual heat removal system on the steam generator secondary side to mitigate non-LOC accidents. A passive heat exchanger combining water and air cooling is used outside the containment vessel to achieve both short-term and long-term core cooling. A liquid storage chamber is provided between the shield wall and the containment vessel, serving as the cooling water source for the passive heat exchanger. This long-term passive cooling system effectively reduces peak containment pressure after an accident and enables long-term passive heat removal, significantly improving unit operational safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above and other features, properties and advantages of the present invention will become more apparent through the following description in conjunction with the accompanying drawings and embodiments, in which like reference numerals represent like features throughout, wherein:

[0026] Figure 1 This is a schematic structural diagram of the long-term passive cooling system of the compact small reactor of the present invention.

[0027] Reference numerals

[0028] Containment 10

[0029] Reactor 20

[0030] Steam generator 30

[0031] Liquid storage chamber 40

[0032] Passive heat exchanger 50

[0033] Passive heat pipe 60

[0034] Exit 11

[0035] Import pipeline 31

[0036] Inlet isolation valve 32

[0037] Export pipeline 33

[0038] Outlet isolation valve 34

[0039] Balance Board 41

[0040] Cooling air inlet 42

[0041] Balanced air intake 43

[0042] Shielding Wall 44

[0043] First chamber A

[0044] Second chamber B DETAILED DESCRIPTION

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0046] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Reference will now be made in detail to preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numerals will be used throughout the drawings to represent the same or similar parts.

[0047] Furthermore, although the terms used in the present invention are selected from well-known and commonly used terms, some terms mentioned in the present specification may be selected by the applicant at his or her discretion, and their detailed meanings are explained in the relevant parts of the description herein.

[0048] Furthermore, it is required that the present invention be understood not only by the actual terms used but also by the meanings lying behind each term.

[0049] like Figure 1 As shown, the present invention discloses a long-term passive cooling system for a compact small reactor, comprising: a containment vessel 10, a reactor 20, and at least one set of cooling circulation systems, wherein the cooling circulation systems are arranged around the reactor 20 (e.g., Figure 1 As shown, two sets of cooling circulation systems are symmetrically arranged on both sides of the reactor 20. Of course, this is only an example, and more sets of cooling circulation systems can be included. The structure of each cooling circulation system is the same. In this application, one cooling circulation system is used as an example for detailed description. The structures of the other cooling circulation systems are the same and will not be described in detail.

[0050] A cooling cycle system includes at least one steam generator 30, a liquid storage chamber 40 (e.g., using cooling water as the coolant), at least one passive heat exchanger 50, and multiple passive heat pipes 60. Reactor 20: The reactor 20 and steam generators 30 are installed within a containment vessel 10. The steam generators 30 are connected to the reactor 20, and each steam generator 30 is equipped with a secondary side waste heat removal system. An outlet 11 is provided at the top of the containment vessel 10 for discharging heat from the liquid storage chamber 40.

[0051] The secondary side waste heat removal system includes an inlet pipe 31, an inlet isolation valve 32, an outlet pipe 33 and an outlet isolation valve 34. The inlet pipe 31 is connected between the outlet end of the steam generator 30 and the inlet end of the passive heat exchanger 50, and the outlet pipe 33 is connected between the outlet end of the passive heat exchanger 50 and the outlet end of the steam generator 30. The inlet isolation valve 32 is installed on the inlet pipe 31, and the outlet isolation valve 34 is installed on the outlet pipe 33.

[0052] The liquid storage chamber 40 is mounted around the outer wall of the containment vessel 10. A passive heat exchanger 50 is disposed within the liquid storage chamber 40 and connected to the secondary side waste heat removal system of the corresponding steam generator 30, allowing steam from the steam generator 30 to enter the passive heat exchanger 50 for heat exchange. A passive heat pipe 60 is installed through the wall of the containment vessel 10 to transfer heat from the containment vessel 10 to the liquid storage chamber 40. The liquid storage chamber 40 contains a cooling liquid, such as cooling water.

[0053] In the event of a loss of coolant, the heat of the high-temperature, high-pressure steam in the containment vessel 10 is transferred to the outside of the containment vessel 10 via the passive heat pipe 60. The liquid storage chamber 40 provided between the shielding wall and the containment vessel 10 serves as a cooling water source for the passive heat pipe 60 outside the containment vessel 10. This structural design can suppress the pressure and temperature of the containment vessel in the early stages of a loss of coolant.

[0054] Preferably, the long-term passive cooling system includes a plurality of passive heat exchangers 50 , which are connected in series between the inlet pipe 31 and the outlet pipe 33 . The passive heat exchangers 50 are immersed in the cooling liquid in the liquid storage chamber 40 .

[0055] Further preferably, a balancing plate 41 extending from top to bottom is disposed within the liquid storage chamber 40. At least one cooling air inlet 42 is provided on the outer wall of the liquid storage chamber 40, and at least one balancing air inlet 43 is provided on the balancing plate 41. External cooling air enters the first chamber A between the balancing plate 41 and the outer wall of the liquid storage chamber 40 through the cooling air inlet 42, and then enters the second chamber B between the balancing plate 41 and the containment vessel 10 through the balancing air inlet 43, thereby cooling the passive heat exchanger 50.

[0056] In this embodiment, a plurality of balancing air inlets 43 are formed on the balancing plate 41 , and the balancing air inlets 43 are spaced apart from each other. Each passive heat exchanger 50 is located at the outlet side of the corresponding balancing air inlet 43 .

[0057] Here, the outer wall of the liquid storage chamber 40 is preferably a shield wall 44. The liquid storage chamber 40 is disposed between the shield wall and the containment vessel 10, serving as a cooling water source for the passive heat exchanger 50. A balancing plate 41 is disposed between the shield wall and the containment vessel 10, dividing the liquid storage chamber 40 into two chambers. A balancing air inlet 43 is provided on the balancing plate 41, serving as a connecting vessel between the two chambers to ensure the same liquid level. After the water evaporates, it also serves as an air inlet channel to cool the passive heat exchanger 50, achieving a transition from water cooling to air cooling.

[0058] When the water in the liquid storage chamber 40 evaporates, the air in the balanced air inlet 43 is used as a cold source for the passive heat pipe 60 to continue to reduce the containment pressure and temperature in the later stage of the loss of coolant accident and to remove the decay heat of the core for a long time.

[0059] According to the above structural description, the connection of the above components is only an exemplary description of the present invention and is not a restrictive description. Other connection methods can also be used.

[0060] When the compact small reactor operates normally, the inlet isolation valve 32 and the outlet isolation valve 34 of the secondary side residual heat removal system are closed, the liquid storage chamber 40 maintains a certain amount of coolant (for example, cooling water is used as the coolant), the passive heat exchanger 50 and the passive heat pipe 60 are in standby state, and the liquid storage chamber 40 is in standby state.

[0061] When a non-loss of coolant accident (LOCA) occurs in the compact small reactor, the inlet and outlet isolation valves 32 and 34 of the secondary side residual heat removal system are opened, and steam from the steam generator 30 flows through the inlet pipe 31 of the secondary side residual heat removal system into the passive heat exchanger 50. The passive heat exchanger 50, submerged in the liquid storage chamber 40, is cooled by a coolant (e.g., cooling water). The passive heat exchanger 50, located in the air space above the liquid storage chamber 40, is cooled by air from the cooling air inlet 42 and the upper balancing air inlet 43.

[0062] Meanwhile, taking the cooling water contained in the liquid storage chamber 40 as an example, the cooling water in the liquid storage chamber 40 is heated. When the water temperature rises to the saturation temperature, the water volume is continuously reduced through boiling. The cooled fluid enters the steam generator 30 through the outlet pipe 33 of the secondary side waste heat removal system, completing the cooling cycle and removing the decay heat from the reactor 20.

[0063] When the water in the water storage chamber 40 evaporates, the passive heat exchanger 50 is cooled mainly through the air from the cooling air inlet 42 and the upper balance air inlet 43, realizing the transition from water cooling to complete air cooling, and the transition from short-term cooling to long-term cooling.

[0064] When a loss of coolant (LOC) accident occurs in a compact small reactor, a large amount of steam is ejected into the containment vessel 10, causing the pressure and temperature within the containment vessel 10 to rise continuously. At this point, heat is primarily dissipated into the cold water in the liquid storage chamber 40 via the passive heat pipes 60 that penetrate the containment vessel 10. Simultaneously, air from the cooling air inlet 42 and the upper balancing air inlet 43 also cools the passive heat pipes 60 above the containment vessel 10.

[0065] When the water in the liquid storage chamber 40 evaporates, the passive heat pipe 60 is cooled mainly by the air from the cooling air inlet 42 and the upper balanced air inlet 43, realizing the transition from water cooling to complete air cooling, and the transition from short-term cooling to long-term cooling, thereby achieving long-term cooling.

[0066] The above working process is to mitigate non-LOCA accidents by setting up a passive residual heat removal system in the steam generator secondary, and to achieve short-term and long-term core cooling outside the containment vessel 10 through water-cooled passive heat exchange and air-cooled passive heat exchange.

[0067] The long-term passive cooling system, through the provision of a passive heat pipe 60, reduces the pressure and temperature within the containment vessel 10 in the event of a loss of coolant accident. The liquid storage chamber 40 serves as both the cooling water source for the passive heat exchanger and the water source for the passive heat pipe. Through the cooling air inlet 42 and the balancing air inlet 43, the transition from water cooling to air cooling, as well as the transition from short-term cooling to long-term cooling, is achieved. This long-term passive cooling system effectively reduces the peak pressure of the containment vessel after an accident and enables long-term passive heat transfer, significantly improving the operational safety of the unit.

[0068] As described above, the long-term passive cooling system for the compact small reactor of the present invention has the following characteristics:

[0069] 1. A passive residual heat removal system is installed in the secondary steam generator to mitigate non-LOCA accidents. Short-term and long-term core cooling is achieved outside the containment through a passive heat exchanger combining water cooling and air cooling. A liquid storage chamber 40 is provided between the shield wall and the containment 10 as a cooling water source for the passive heat exchanger 50.

[0070] Second, a balancing plate is installed between the shield wall and containment vessel 10, dividing the water storage chamber into two chambers. A balancing air inlet 43 is provided on the balancing plate 41, serving as a connecting vessel between the two chambers to ensure equal liquid levels. After the water evaporates, it also serves as an inlet channel to cool the passive heat exchanger 50, achieving a transition from water-cooling to air-cooling.

[0071] Third, a passive heat pipe 60 is provided that penetrates the containment vessel 10. In the event of a loss of coolant (LOC) accident, the heat of the high-temperature, high-pressure steam within the containment vessel 10 is transferred to the exterior of the containment vessel 10 via the passive heat pipe 60. A liquid storage chamber 40 is provided between the shield wall and the containment vessel 10 as a cooling water source for the passive heat pipe 60 outside the containment vessel 10. This structure can suppress the containment vessel pressure and temperature in the early stages of a LOC accident.

[0072] Fourth, after the water in the liquid storage chamber 40 evaporates, the air in the balanced air inlet 43 is used as a cold source for the passive heat pipe 60 to continue to reduce the containment pressure and temperature in the later stage of the loss of coolant accident and to remove the decay heat of the core for a long time.

[0073] 5. A cooling air inlet 42 is provided on the shielding wall, serving as a cooling source after the water in the liquid storage chamber 40 evaporates. The cooling air flows through the descending chamber and enters the ascending chamber through the balanced air inlet 43, cooling the passive heat exchanger 50 and the passive heat pipe 60, removing the decay heat of the core for a long time, and maintaining the pressure and temperature of the containment within the limit.

[0074] In summary, the long-term passive cooling system for a compact small reactor of the present invention incorporates a secondary side residual heat removal system on the steam generator secondary side to mitigate non-LOCA accidents. It also achieves short-term and long-term core cooling via a passive heat exchanger combining water and air cooling outside the containment vessel. A liquid storage chamber is provided between the shield wall and the containment vessel, serving as the cooling water source for the passive heat exchanger. This long-term passive cooling system effectively reduces peak containment pressure after an accident and enables long-term passive heat removal, significantly improving unit operational safety.

[0075] For those skilled in the art, the above invention disclosure is intended only as an example and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and amendments to this application. Such modifications, improvements, and amendments are suggested in this application and remain within the spirit and scope of the exemplary embodiments of this application.

[0076] At the same time, this application uses specific terms to describe the embodiments of this application. For example, "one embodiment," "an embodiment," and / or "some embodiments" refer to a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "one embodiment," "an embodiment," or "an alternative embodiment" mentioned twice or multiple times in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application may be appropriately combined.

[0077] Similarly, it should be noted that, in order to simplify the description of the present disclosure and thus facilitate understanding of one or more embodiments of the invention, the foregoing descriptions of the embodiments of the present disclosure sometimes combine multiple features into a single embodiment, figure, or description thereof. However, this disclosure method does not mean that the subject matter of the present disclosure requires more features than those recited in the claims. In fact, the features of an embodiment may be fewer than the total features of a single embodiment disclosed above.

[0078] Although specific embodiments of the present invention have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, and such changes and modifications are intended to fall within the scope of the present invention.

Claims

1. A long-term passive cooling system for a compact small reactor, characterized in that: The long-term passive cooling system includes: A containment vessel, a reactor, and at least one steam generator, wherein the reactor and the steam generator are installed in the containment vessel, the steam generator is connected to the reactor, and each steam generator is provided with a secondary side waste heat removal system; a liquid storage chamber, the liquid storage chamber being circumferentially mounted on the outer wall of the containment vessel; at least one passive heat exchanger, the passive heat exchanger being arranged in the liquid storage chamber and connected to the secondary side waste heat removal system of the corresponding steam generator, so that steam from the steam generator enters the passive heat exchanger for heat exchange; A plurality of passive heat pipes are installed through the wall of the containment shell and are used to conduct heat in the containment shell to the liquid storage chamber.

2. The long-term passive cooling system for a compact small reactor according to claim 1, wherein: The secondary side waste heat removal system includes an inlet pipe, an inlet isolation valve, an outlet pipe and an outlet isolation valve. The inlet pipe is connected between the outlet end of the steam generator and the inlet end of the passive heat exchanger, and the outlet pipe is connected between the outlet end of the passive heat exchanger and the outlet end of the steam generator. The inlet isolation valve is installed on the inlet pipe, and the outlet isolation valve is installed on the outlet pipe.

3. The long-term passive cooling system for a compact small reactor according to claim 2, wherein: The long-term passive cooling system includes a plurality of passive heat exchangers, which are connected in series between the inlet pipe and the outlet pipe.

4. The long-term passive cooling system for a compact small reactor according to claim 1, wherein: The liquid storage chamber is filled with cooling liquid.

5. The long-term passive cooling system for a compact small reactor according to claim 4, characterized in that: The passive heat exchanger is immersed in the cooling liquid in the liquid storage chamber.

6. The long-term passive cooling system for a compact small reactor according to claim 1, wherein: A balancing plate extending from top to bottom is provided in the liquid storage chamber, at least one cooling air inlet is provided on the outer wall of the liquid storage chamber, and at least one balancing air inlet is provided on the balancing plate. External cooling air enters the first chamber between the balancing plate and the outer wall of the liquid storage chamber through the cooling air inlet, and then enters the second chamber between the balancing plate and the containment shell through the balancing air inlet, for cooling the passive heat exchanger.

7. The long-term passive cooling system for a compact small reactor according to claim 6, wherein: The outer side wall of the liquid storage chamber is a shielding wall.

8. The long-term passive cooling system for a compact small reactor according to claim 6, wherein: The balancing plate is provided with a plurality of balancing air inlets, and the balancing air inlets are arranged at intervals from each other.

9. The long-term passive cooling system for a compact small reactor according to claim 8, wherein: Each of the passive heat exchangers is located at the air outlet side of the corresponding balanced air inlet.

10. The long-term passive cooling system for a compact small reactor according to claim 1, wherein: An outlet is provided on the upper portion of the containment shell for discharging heat from the liquid storage chamber.

Images