Melt in-pile retention passive emergency cooling system and method for ocean nuclear power platform

Abstract

The invention relates to a melt in-pile retention passive emergency cooling system and method for an ocean nuclear power platform, and the passive emergency cooling system comprises an emergency cooling channel, a bottom cooling channel, a water diversion pipeline, a water taking pipeline, a water drainage pipeline and an exhaust pipeline, the emergency cooling channel and the bottom cooling channel are communicated with seawater through the water diversion pipeline, the water taking pipeline, the water discharging pipeline and the air discharging pipeline, and a natural circulation channel is formed. According to the passive emergency cooling system disclosed by the invention, double bottoms at the bottoms of a reactor pressure vessel and an ocean nuclear power platform are respectively subjected to sealing transformation to form a seawater emergency cooling channel and a bottom cooling channel; according to the passive emergency cooling system, a series of passive methods are utilized, the passive emergency cooling system is put in a passive mode in a severe scene of power interruption after a serious accident of an ocean nuclear power platform, heat of a reactor core melt is safely and reliably guided out, and long-term cooling of the reactor core is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of passive emergency cooling of marine nuclear power platforms, and in particular to a passive emergency cooling system and method for molten material retention in a marine nuclear power platform. Background Art

[0002] As my country continues to develop marine resources, the demand for stable, reliable, and large-capacity offshore electricity and heat supply has become more urgent. Since the energy density of nuclear fuel is much higher than that of traditional fossil energy, marine nuclear power platforms can provide sufficient electricity and heat for remote islands and reefs and offshore oil and gas development in a long-term and reliable manner, and have good market prospects.

[0003] The external marine environment faced by offshore nuclear power platforms is more complex than that of onshore nuclear power plants. The risk of nuclear accidents is theoretically higher than that of onshore nuclear power plants. They may also be deployed in remote sea areas, and accident rescue is far more difficult than that of ordinary nuclear power plants. After a nuclear accident, if the primary coolant is lost, the core may be exposed, and it will heat up and melt due to decay heat. The core molten material will accumulate in the lower head of the reactor pressure vessel due to gravity. If there are no emergency heat conduction measures at this time, the molten material will continue to melt through the lower head, causing the reactor pressure vessel to fail, resulting in a large amount of radioactive materials being released into the containment, and even increasing the risk in the environment, causing marine environmental pollution and international disputes.

[0004] At present, the main measures to prevent reactor pressure vessel failure in third-generation nuclear power plants are: (1) discharging residual heat from the core by filling and draining water on the secondary side of the steam generator; (2) using a pressurizer pressure relief valve to discharge residual heat from the core by filling and draining water in a single loop; (3) injecting water to flood the pit to cool the pressure vessel, etc., which generally requires the installation of a large water tank as a cooling water source.

[0005] Due to the limited space on offshore nuclear power platforms, it is difficult to set up sufficient severe accident mitigation measures in accordance with nuclear power plants. Therefore, it is quite difficult to mitigate severe accidents on offshore nuclear power platforms. Summary of the invention

[0006] In view of this, the present invention provides a passive emergency cooling system and method for molten material retention in an offshore nuclear power platform. In the event of a serious accident, the passive emergency cooling system is used to introduce seawater into the containment and submerge the outer wall of the reactor pressure vessel, ensuring that the core molten material is retained inside the reactor pressure vessel. By passive means, long-term cooling of the core and effective discharge of heat in the reactor pressure vessel are achieved, and the damage to the reactor pressure vessel barrier is prevented, thereby achieving the purpose of alleviating serious accidents.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions.

[0008] In a first aspect, the present invention provides a passive emergency cooling system for molten material retention in an offshore nuclear power platform, comprising an emergency cooling channel, a bottom cooling channel, a water diversion pipeline, a water intake pipeline, a drainage pipeline and an exhaust pipeline, wherein the water diversion pipeline, the water intake pipeline, the drainage pipeline and the exhaust pipeline connect the emergency cooling channel and the bottom cooling channel with seawater to form a natural circulation channel; wherein,

[0009] The emergency cooling channel is formed by a shielding water tank (or a primary shielding water tank) surrounding the reactor pressure vessel and a supporting structure of the reactor pressure vessel;

[0010] The bottom cooling channel is formed by arranging a double bottom enclosure in the double bottom of the platform below the reactor pressure vessel to enclose the double bottom into a closed space;

[0011] The water diversion pipeline is between the bottom cooling channel and the emergency cooling channel; the water intake pipeline connects seawater to the water diversion pipeline through a sea valve box;

[0012] A discharge pipeline is arranged at the top of the emergency cooling channel, and the discharge pipeline is respectively connected with the exhaust pipeline and the drainage pipeline.

[0013] The passive emergency cooling system provided by the present invention adopts sealing modification of the reactor pressure vessel and the double bottom of the bottom of the marine nuclear power platform (i.e., the double bottom of the platform below the reactor pressure vessel, including the upper plate of the platform and the outer plate of the bottom of the platform) to form a seawater emergency cooling channel and a bottom cooling channel. The passive emergency cooling system can be put into use in a passive manner under the condition of a serious accident on the marine nuclear power platform to ensure long-term cooling of the core.

[0014] As an optional implementation, in the emergency cooling channel, the shielding water tank and the supporting structure are sealed on one side close to the reactor pressure vessel to form a closed space that can be used to fill with seawater after an accident.

[0015] As an optional implementation, the height of the enclosed space is higher than the highest point of the core assembly in the reactor pressure vessel. This arrangement can ensure that seawater can submerge the main heat source of the reactor pressure vessel after an accident, effectively removing the heat from the core.

[0016] As an optional implementation, the interface of the water diversion pipeline is arranged at the top of the bottom cooling channel to ensure that the seawater can completely submerge the double bottom, evacuate the gas between the double bottom, and improve the heat transfer efficiency; after the bottom cooling channel is filled with seawater, it is injected into the emergency cooling channel through the water diversion pipeline.

[0017] As an optional implementation, the valve of the water diversion pipeline (for example, ) is arranged outside the shielding water tank to reduce the radioactive irradiation of the nuclear reactor to the valve and facilitate equipment maintenance.

[0018] As an optional embodiment, the valve of the water diversion pipeline adopts a pneumatic ball valve (such as Figure 1 Pneumatic ball valve at the bottom of the containment as shown).

[0019] As an optional embodiment, the valves of the water diversion pipeline are at least 2 (such as Figure 1 Pneumatic ball valves 6 and 7 at the bottom of the containment vessel are shown).

[0020] As an optional implementation, the sea chest is arranged in the bottom platform of the side cabin.

[0021] In the present invention, after an accident occurs, seawater is introduced into the bottom cooling channel through the sea valve box, the air is discharged and the channel is filled with seawater; the seawater in the emergency cooling channel can transfer heat to the bottom cooling channel through the steel structure below the reactor pressure vessel (e.g., the upper plate of the platform), and then conduct the heat to the seawater through the bottom outer plate of the platform.

[0022] As an optional implementation, a sea valve is provided on the top of the sea valve box.

[0023] As an optional implementation, a suction grille is provided at the bottom of the sea valve box.

[0024] As an optional implementation, the outlet of the exhaust pipeline is higher than the horizontal line of the sea water.

[0025] In the present invention, the exhaust pipeline is used to exhaust the gas that affects the heat transfer effect, which can ensure that the seawater completely submerges the cooling channel (for example, the emergency cooling channel). The drainage pipeline can be combined with the water intake pipeline to form a natural circulation channel for emergency cooling.

[0026] As an optional implementation, the water intake pipeline is also provided with a containment water inlet isolation valve.

[0027] As an optional implementation, the discharge pipeline is provided with a containment discharge isolation valve.

[0028] As an optional implementation, the drainage pipeline is provided with a side sea valve (for example, a side sea ball valve).

[0029] As an optional implementation, the exhaust pipeline is provided with a side exhaust valve (eg, a side exhaust ball valve).

[0030] The passive emergency cooling system provided by the present invention is used for introducing seawater into and submerging the outer wall of the reactor pressure vessel under severe accident conditions of an offshore nuclear power platform, and using a variety of passive methods to extract the heat of the molten material in the reactor pressure vessel, thereby ensuring long-term cooling of the core and preventing damage to the boundary barrier of the reactor pressure vessel, thereby effectively preventing failure of the containment barrier.

[0031] In a second aspect, the present invention provides a passive emergency cooling method for a molten material retained in a marine nuclear power platform, which is implemented by using the above-mentioned passive emergency cooling system. The passive emergency cooling method comprises the following steps:

[0032] 1) The bottom cooling channel and the emergency cooling channel are connected to the external atmospheric space through the exhaust pipeline;

[0033] 2) Allow seawater to enter the bottom cooling channel through the water intake pipeline, and then enter the emergency cooling channel through the water diversion pipeline;

[0034] 3) Allow seawater to enter the emergency cooling channel from the water intake pipeline through the water diversion pipeline to submerge the reactor pressure vessel;

[0035] 4) Connect the drainage pipeline, emergency cooling channel and water intake pipeline to form a natural circulation channel.

[0036] In the present invention, under the standby condition (i.e., when the marine nuclear power platform is operating normally), the passive emergency cooling system is in a standby state. Specifically, the emergency cooling channel, the bottom cooling channel, the water intake pipeline and the exhaust pipeline are all in a standby state, and each valve in the passive emergency cooling system is in a closed state, and the emergency cooling channel and the bottom cooling channel are in a closed state. Under severe accident conditions (i.e., a severe accident occurs in the marine nuclear power platform), the above-mentioned passive emergency cooling method is used for emergency treatment. For example, when it is determined that the reactor core may melt and the core heat cannot be effectively discharged, a series of valves on the water intake, drainage and exhaust pipelines are opened, and seawater is quickly injected into the bottom cooling channel and the emergency cooling channel, and finally the cooling channel is completely submerged, so as to achieve safe and reliable extraction of the heat of the core melt.

[0037] As an optional implementation, in step 1), the side exhaust valve, the containment discharge isolation valve, the pneumatic ball valve at the bottom of the containment, and the containment water inlet isolation valve are opened to connect the bottom cooling channel and the emergency cooling channel with the external atmospheric space.

[0038] As an optional implementation, in step 2), the sea valve is opened, and seawater is sucked into the sea valve box from the bottom of the sea valve through the grid, and flows through the containment water inlet isolation valve into the bottom cooling channel.

[0039] As an optional implementation, in step 3), the pneumatic ball valve at the bottom of the containment is opened to allow seawater from the sea chest to be injected into the emergency cooling channel, exhaust the gas therein, and submerge the reactor pressure vessel.

[0040] As an optional implementation, in step 4), the side sea valve is opened to connect the drainage pipeline, the emergency cooling channel and the water intake pipeline to form a natural circulation channel.

[0041] In the present invention, under standby conditions, that is, when the marine nuclear power platform is operating normally, the emergency cooling channel of the reactor pressure vessel, the bottom cooling channel, and the water intake and exhaust pipelines are all in standby state, each pneumatic valve is in a closed state, and the emergency cooling channel and the bottom cooling channel are in a sealed state. Under severe accident conditions, that is, when it is judged that the reactor core may melt and the core heat cannot be effectively discharged, a series of valves on the water intake, drainage and exhaust pipelines are opened to quickly inject seawater into the bottom cooling channel and the emergency cooling channel, and finally completely submerge the cooling channel to achieve safe and reliable heat removal of the core melt.

[0042] In the present invention, at the initial stage of the accident, seawater directly enters the emergency cooling channel through the sea valve, the containment water inlet isolation valve, and the pneumatic ball valve at the bottom of the containment. After being heated by the reactor pressure vessel, the density of the seawater decreases, and it flows upward, and is discharged from the side after passing through the containment discharge isolation valve and the side sea valve, forming a natural circulation flow. At the end of the accident, the decay heat in the reactor pressure vessel decreases, and the natural circulation flow is reduced or interrupted. The heat in the emergency cooling channel is conducted to the steel plate at the bottom of the containment through convection, and then conducted to the seawater in the bottom cooling channel. The bottom outer plate of the platform is in direct contact with the external seawater, and the heat of the bottom cooling channel is dissipated into the seawater. At the initial stage of the accident, part of the heat in the reactor pressure vessel can also be transferred to the seawater through the bottom outer plate 12 of the platform, but natural circulation heat transfer is the mainstream.

[0043] In the present invention, the above technical features can be freely combined to form a new technical solution without conflicting with each other.

[0044] The beneficial effects brought by the present invention are as follows:

[0045] (1) The passive emergency cooling system for molten material retention in a marine nuclear power platform provided by the present invention utilizes a series of passive methods to safely and reliably remove the heat of the core molten material in the severe scenario of power outage after a serious accident. Specifically, the seawater level difference is utilized to passively introduce emergency cooling seawater to submerge the outer wall of the reactor pressure vessel. Natural circulation is utilized to passively transfer a large amount of heat accumulated in the reactor pressure vessel to the seawater outside the ship at the beginning of the accident, so that the reactor pressure vessel can be quickly cooled and depressurized after a serious accident to maintain the integrity of the second barrier. Heat conduction and heat convection are utilized to passively transfer the reactor decay heat to the outer plate at the bottom of the platform at the end of the accident, so that the core heat can be reliably removed to the seawater for a long time.

[0046] (2) The passive emergency cooling system for molten material retention in the marine nuclear power platform provided by the present invention efficiently utilizes the original space and structure of the marine nuclear power platform, and utilizes the existing shielding water tank and supporting structure, double bottom structure, sea valve box and other structures and equipment. Only limited sealing coamings, pipelines and valves need to be added to implement the solution, which occupies less resources and has high space utilization rate;

[0047] (3) The present invention provides a passive emergency cooling system for molten metal retention in an offshore nuclear power platform. The emergency cooling seawater only floods the limited space between the outer wall of the reactor pressure vessel and the shielding water tank, and does not enter the containment. This will not damage important equipment inside the containment, and is convenient for emergency repairs and emergency decontamination in the later stages of an accident. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 The schematic diagram of the structure of a passive emergency cooling system for molten material retention in an offshore nuclear power platform according to the present invention is shown.

[0049] Markings in the figure are: 1—reactor pressure vessel, 2—intake grid, 3—sea valve box, 4—sea valve, 5—containment water inlet isolation valve, 6—containment bottom pneumatic ball valve, 7—containment bottom pneumatic ball valve, 8—containment discharge isolation valve, 9—side sea valve, 10—side exhaust ball valve, 11—double bottom coaming, 12—platform bottom outer plate. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described below in combination with the embodiments of the present invention and the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] A passive emergency cooling system for molten material retention in an offshore nuclear power platform, such as Figure 1 As shown, it includes an emergency cooling channel, a bottom cooling channel, a water diversion pipeline, a water intake pipeline, a drainage pipeline and an exhaust pipeline. The water diversion pipeline, the water intake pipeline, the drainage pipeline and the exhaust pipeline connect the emergency cooling channel and the bottom cooling channel with seawater to form a natural circulation channel. Specifically,

[0053] An emergency cooling channel is formed by the shielding water tank (or primary shielding water tank) surrounding the reactor pressure vessel 1 and the supporting structure of the reactor pressure vessel 1. In the emergency cooling channel, the shielding water tank and the supporting structure are sealed on the side close to the reactor pressure vessel 1 to form a closed space, which can be filled with seawater after an accident. The height of the closed space is higher than the highest point of the core assembly in the reactor pressure vessel 1 to ensure that the seawater can submerge the main heat source of the reactor pressure vessel 1 after an accident and effectively remove the heat from the core.

[0054] A bottom cooling channel is formed by arranging a double bottom enclosure 11 in the double bottom (including an upper plate (not marked in the figure) and a bottom outer plate 12) of the platform below the reactor pressure vessel 1, so as to enclose the double bottom into a closed space;

[0055] The water diversion pipeline is located between the bottom cooling channel and the emergency cooling channel, and its interface is arranged at the top of the bottom cooling channel, on which are arranged pneumatic ball valves 6 and 7 at the bottom of the containment vessel outside the shielding water tank.

[0056] The water intake pipeline connects seawater to the water intake pipeline through a sea valve box 3 and a containment water inlet isolation valve 5 arranged thereon, wherein the sea valve box 3 is arranged in the bottom platform of the side cabin, a sea valve 4 is arranged on the top, and a bottom suction grid is arranged at the bottom.

[0057] A discharge pipeline is arranged at the top of the emergency cooling channel, on which a containment discharge isolation valve 8 is arranged; the discharge pipeline is connected with the exhaust pipeline and the drainage pipeline respectively, and a side exhaust ball valve 10 is arranged on the exhaust pipeline, and its outlet is higher than the sea level, which is used to discharge the gas that affects the heat transfer effect, and ensure that the cooling channel (for example, the emergency cooling channel) is completely submerged by seawater. A side sea ball valve is arranged on the drainage pipeline.

[0058] The exhaust pipeline and the drainage pipeline can be combined with the water intake pipeline to form a natural circulation channel for emergency cooling.

[0059] The passive emergency cooling system provided in this embodiment is used to introduce seawater into and submerge the outer wall of the reactor pressure vessel 1 under severe accident conditions of an offshore nuclear power platform, and use a variety of passive methods to extract the heat of the molten material in the reactor pressure vessel 1, thereby ensuring long-term cooling of the core and preventing damage to the boundary barrier of the reactor pressure vessel 1, thereby effectively preventing failure of the containment barrier.

[0060] Example 2

[0061] This embodiment provides a method for passive emergency cooling of molten material retained in a reactor for an offshore nuclear power platform, which is implemented using the passive emergency cooling system for molten material retained in a reactor for an offshore nuclear power platform in Example 1.

[0062] The initial state of the passive emergency cooling system is: the reactor pressure vessel 1 is in normal operating state, the sea valve 4, the containment water inlet isolation 5, the containment bottom pneumatic ball valve 6, the containment bottom pneumatic ball valve 7, the containment discharge isolation valve 8, the side sea ball valve 9, and the side exhaust ball valve 10 are in closed state.

[0063] When a serious accident occurs in an offshore nuclear power platform, the core inside the reactor pressure vessel 1 melts, causing the temperature and pressure inside the reactor pressure vessel 1 to rise sharply. After reaching the set limit, the passive emergency cooling system in Example 1 is used to cool the reactor pressure vessel 1. The specific cooling method is as follows:

[0064] 1) Open the side exhaust ball valve 10, the containment discharge isolation valve 8, the pneumatic ball valve 7 at the bottom of the containment, and the containment water inlet isolation valve 5 to connect the bottom cooling channel and the emergency cooling channel with the external atmospheric space;

[0065] 2) Open the sea valve 4 on the sea valve box 3, and the seawater is sucked into the grid 2 from the bottom and enters the sea valve box 3, and flows through the containment water inlet isolation valve 5 into the bottom cooling channel; the seawater is injected into the bottom cooling channel and the gas therein is discharged; after the seawater is filled, the seawater in the bottom cooling channel enters the emergency cooling channel through the pneumatic ball valve 7 at the bottom of the containment;

[0066] 3) Open the pneumatic ball valve 6 at the bottom of the containment, and inject the seawater from the sea chest directly into the emergency cooling channel; after the seawater is injected into the emergency cooling channel, the gas therein is discharged, and the reactor pressure vessel 1 is gradually submerged;

[0067] 4) Open the side sea ball valve 9 to connect the drainage pipeline (i.e., the seawater pipeline on the top of the side), the emergency cooling channel and the water intake pipeline to form a natural circulation channel.

[0068] At the beginning of the accident, seawater directly enters the emergency cooling channel through the sea valve 4, the containment water inlet isolation valve 5, and the pneumatic ball valve 6 at the bottom of the containment. After being heated by the reactor pressure vessel 1, the density of the seawater decreases and it flows upward, and is discharged from the side after passing through the containment discharge isolation valve 8 and the side sea ball valve 9, forming a natural circulation flow.

[0069] At the end of the accident, the decay heat in the reactor pressure vessel 1 decreases, and the natural circulation flow decreases or is interrupted. The heat in the emergency cooling channel is transferred to the steel plate at the bottom of the containment by convection, and then transferred to the seawater in the bottom cooling channel. The platform bottom outer plate 12 is in direct contact with the external seawater, dissipating the heat in the bottom cooling channel into the seawater.

[0070] In the early stage of the accident, part of the heat in the reactor pressure vessel 1 can also be transferred to the seawater through the platform bottom outer plate 12, but natural circulation heat transfer is the mainstream.

[0071] Through the above methods, the core heat can be exported to seawater reliably and long-term, ensuring that the reactor that loses power after a serious accident can be effectively cooled in a timely manner.

[0072] The above are preferred embodiments of the present invention, but the present invention should not be limited to the contents disclosed in the embodiments and the accompanying drawings. It should be pointed out that, for ordinary technicians in this technical field, several improvements and modifications can be made to the above technical solutions without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A passive emergency cooling system for molten material retention in an offshore nuclear power platform, characterized in that: The passive emergency cooling system includes an emergency cooling channel, a bottom cooling channel, a water diversion pipeline, a water intake pipeline, a drainage pipeline and an exhaust pipeline. The water diversion pipeline, the water intake pipeline, the drainage pipeline and the exhaust pipeline connect the emergency cooling channel and the bottom cooling channel with seawater to form a natural circulation channel; wherein, The emergency cooling channel is formed by a shielding water tank (or a primary shielding water tank) surrounding the reactor pressure vessel and a supporting structure of the reactor pressure vessel; The bottom cooling channel is formed by arranging a double bottom enclosure in the double bottom of the platform below the reactor pressure vessel to enclose the double bottom into a closed space; The water diversion pipeline is between the bottom cooling channel and the emergency cooling channel; the water intake pipeline connects seawater to the water diversion pipeline through a sea valve box; A discharge pipeline is arranged at the top of the emergency cooling channel, and the discharge pipeline is respectively connected with the exhaust pipeline and the drainage pipeline.

2. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 1 is characterized in that: In the emergency cooling channel, the shielding water tank and the supporting structure are sealed on one side close to the reactor pressure vessel to form a closed space.

3. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 2 is characterized in that: The height of the enclosed space is higher than the highest point of the core assembly in the reactor pressure vessel.

4. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 1, characterized in that: The interface of the water diversion pipeline is arranged at the top of the bottom cooling channel; or / and A valve is arranged on the water diversion pipeline, and the valve of the water diversion pipeline is arranged outside the shielding water tank.

5. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 4, characterized in that: The valve of the water diversion pipeline adopts a pneumatic ball valve; or / and The water diversion pipeline has at least two valves.

6. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 1, characterized in that: The sea chest is arranged in the bottom platform of the side cabin.

7. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 1 or 6, characterized in that: The top of the sea valve box is provided with a sea valve, and the bottom is provided with a suction grid.

8. The passive emergency cooling system for molten material retention in a marine nuclear power platform according to claim 1, characterized in that: The outlet of the exhaust pipe is above the sea level; and / or The water intake pipeline is also provided with a containment water inlet isolation valve; the discharge pipeline is provided with a containment discharge isolation valve; the drainage pipeline is provided with a side sea valve; and the exhaust pipeline is provided with a side exhaust valve.

9. A passive emergency cooling method for molten material retention in an offshore nuclear power platform, characterized in that: The passive emergency cooling system according to any one of claims 1 to 8 is used for implementation, and the passive emergency cooling method comprises the following steps: 1) The bottom cooling channel and the emergency cooling channel are connected to the external atmospheric space through the exhaust pipeline; 2) Allow seawater to enter the bottom cooling channel through the water intake pipeline, and then enter the emergency cooling channel through the water diversion pipeline; 3) Allow seawater to enter the emergency cooling channel from the water intake pipeline through the water diversion pipeline to submerge the reactor pressure vessel; 4) Connect the drainage pipeline, emergency cooling channel and water intake pipeline to form a natural circulation channel.

10. The passive emergency cooling method for molten material retention in a marine nuclear power platform according to claim 9, characterized in that: In the step 1), the side exhaust valve, the containment discharge isolation valve, the pneumatic ball valve at the bottom of the containment, and the containment water inlet isolation valve are opened to connect the bottom cooling channel and the emergency cooling channel with the external atmospheric space; or / and In the step 2), the sea valve is opened, seawater is sucked into the grille from the bottom of the sea valve and enters the sea valve box, flows through the containment water inlet isolation valve and enters the bottom cooling channel; or / and In the step 3), the pneumatic ball valve at the bottom of the containment is opened to allow seawater from the sea chest to be injected into the emergency cooling channel, exhaust the gas therein, and submerge the reactor pressure vessel; or / and In the step 4), the side sea valve is opened to connect the drainage pipeline, the emergency cooling channel and the water intake pipeline to form a natural circulation channel.

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