Emergency pre-treatment system for leakage of liquid acid-base chemicals in nuclear power station

Abstract

The invention belongs to the technical field of nuclear power station operation, and particularly relates to an emergency pre-treatment system for nuclear power station liquid acid-base chemical leakage. The chemical storage tank and the acid mist absorber are arranged in the chemical storage plant, the forced exhaust fan is arranged at the top of the chemical storage plant, the chemical storage plant is connected with the safety house through the fireproof door, a pulley, a living water supply pipe, a stay wire, a water supply valve and a hand wheel are arranged in the safety house, and the forced air inlet fan is arranged on the roof of the safety house; a corrosion-resistant ground grid A is laid on the ground of a chemical storage plant, the space below the corrosion-resistant ground grid A is divided into an equipment pit and a leakage pit, a leakage pit overflow pipeline, a leakage pit drainage pump and a drainage mother pipe are arranged in the equipment pit, and a spray head and an acid-base liquid immersion alarm are arranged in the leakage pit. And the chemical storage tank supporting foundation is arranged in the leakage pit. The working efficiency can be improved, and the safety of operators and equipment can be ensured.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power plant operation technology, specifically relating to an emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants. Background Technology

[0002] In nuclear power plants, to ensure the normal operation of the condensate polishing system and the secondary loop continuous chemical dosing system, it is often necessary to use liquid acid and alkali chemicals such as hydrochloric acid, sodium hydroxide, and ammonia. These chemicals are stored in chemical storage tanks in the plant. In the event of a leak, not only will the liquid acid and alkali chemicals be released into the working environment, but also irritating gases such as hydrochloric acid mist and ammonia will be generated.

[0003] Leaks of liquid acid and alkali chemicals not only require a significant amount of time, manpower, and resources, but also pose an industrial safety risk of burns to personnel who become contaminated with hazardous chemicals during operation. There have been numerous cases of personnel being injured while handling hazardous chemicals at power plants in the same industry, indicating a substantial risk of personal injury.

[0004] Therefore, there is a need for a system that can assist operators in the emergency pre-response of liquid acid and alkali chemical leaks, thereby improving work efficiency and ensuring the safety of operators and equipment. Summary of the Invention

[0005] The purpose of this invention is to provide an emergency pre-treatment system for liquid acid and alkali chemical leaks in nuclear power plants, which improves work efficiency and ensures the safety of operating personnel and equipment.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] An emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants: Chemical storage tanks and acid mist absorbers are arranged inside the chemical storage building. Forced exhaust fans are arranged on the roof of the chemical storage building. The chemical storage building is connected to a safety room via fire doors. The safety room is equipped with pulleys, domestic water supply pipes, guy wires, water supply valves, and handwheels. Forced intake fans are arranged on the roof of the safety room. The floor of the chemical storage building is covered with corrosion-resistant ground grating A. The space under the corrosion-resistant ground grating A is divided into an equipment pit and a leak pit. The overflow pipeline, leak pit drainage pump, and drainage header of the leak pit are arranged in the equipment pit. Sprinklers and acid / alkali liquid immersion alarms are arranged in the leak pit. The support foundations for the chemical storage tanks are set in the leak pit. On the ground, a cofferdam surrounds the chemical storage tanks, leak pits, and corrosion-resistant ground grating A. Inside, above the cofferdam and chemical storage tanks, an electric curtain track is arranged around the chemical storage tanks, with soft, transparent plastic curtains hanging on the track. Sprayers are arranged below the electric curtain track. The acid mist absorber is located above the equipment pit. The acid mist absorber exhaust pipe, acid mist absorber air inlet pipe, acid mist absorber overflow pipe, and acid mist absorber water supply pipe are connected to the acid mist absorber. The acid mist absorber air inlet pipe is directly connected to the indoor air, while being submerged below the water level. A gas-liquid separator is installed inside the acid mist absorber exhaust pipe. The acid mist absorber exhaust pipe passes through the factory ceiling to reach the outside. The acid mist absorber body is equipped with an acid mist absorber water supply pipe, a drain pipe, and an acid mist absorber overflow pipe. The medium inside the acid mist absorber is pumped into a pH meter to monitor the medium inside the acid mist absorber.

[0008] The roof of the safe house is equipped with solar panels.

[0009] The medium in the leaking sump enters the leaking sump drainage pump and the leaking sump overflow pipeline through the drain pipe inlet and overflow pipe inlet that pass through the wall.

[0010] The chemical storage tank support foundation is set inside the leak pit and extends upwards to a position more than 2 meters above the ground to provide support for the chemical storage tank. The chemical storage tank support foundation is resistant to corrosion from acid and alkali chemicals.

[0011] A forced exhaust fan is installed at the end of the exhaust pipe of the acid mist absorber.

[0012] Domestic water is used as the absorption medium in the acid mist absorber.

[0013] When replenishing water, domestic water enters the acid mist absorber through the acid mist absorber replenishment pipe and the acid mist absorber replenishment valve. When draining water, the water inside the acid mist absorber enters the overflow pipeline of the leak pit through the drain valve and check valve, and is discharged into the neutralization tank by gravity. When the liquid level inside the acid mist absorber is too high, it enters the overflow pipeline of the leak pit through the acid mist absorber overflow pipeline.

[0014] When a chemical storage tank ruptures and leaks, on-site personnel escape to the safety room through fire doors. The leaked liquid acids and alkalis flow into the leak pit through corrosion-resistant floor grating B. Gas detection probes or acid / alkali immersion alarms installed on the tank's support foundation trigger an alarm. An electric curtain track drives a soft, transparent plastic curtain to encircle the chemical storage tank, preventing the leaked chemicals from splashing outside the containment area. Once the curtain is in place, the water supply valve automatically opens, allowing domestic water to flow through the domestic water supply pipe into the sprinklers. Water is then sprayed into the leak area and leak pit to dilute the chemicals and absorb any ammonia or acid mist present in the air. After dilution by the sprayed water, the chemicals in the leak pit are discharged through a drain pump or overflow pipeline into a neutralization tank via a main drain pipe for neutralization.

[0015] If the electric curtain track fails, the soft transparent plastic curtain does not close properly, or the water supply valve fails and the domestic water is not connected properly, the on-site operator can manually operate the soft transparent plastic curtain to close and the sprinkler system from inside the safety room using handwheels, pull lines, pulleys, and the water supply valve. The safety room has a forced air intake fan that runs continuously to maintain a slightly positive air pressure inside the room, ensuring that toxic and harmful gases from the chemical storage plant do not enter the safety room.

[0016] When the room is filled with ammonia and acid mist, the harmful gases are discharged outdoors through the acid mist absorber. The forced exhaust fan runs continuously, maintaining negative pressure inside the absorber. The harmful gases enter the bottom of the absorber through the inlet pipe and are absorbed by water. The remaining gas is discharged outdoors through the exhaust pipe and the forced exhaust fan. During this process, the discharged gas passes through a gas-water separator, where water mist is separated and condensed to prevent excessive humidity from damaging the forced exhaust fan. The condensed water returns to the absorber by gravity. Inside, the acid mist absorber has an automatic water replacement function. During operation, the sampling pump starts intermittently to deliver water from the acid mist absorber to the pH meter. When the pH meter value exceeds the limit, the water supply valve and drain valve of the acid mist absorber automatically open to replace the water in the acid mist absorber, ensuring its continuous use. When the liquid level in the acid mist absorber is too high, the excess water overflows through the overflow pipeline to prevent the liquid level in the acid mist absorber from entering the exhaust pipe of the acid mist absorber. The check valve on the overflow pipeline prevents the medium in the drain pipeline from entering the acid mist absorber due to negative pressure.

[0017] The beneficial effects achieved by this invention are as follows:

[0018] This invention provides emergency pre-response for leaks of liquid acid and alkali chemicals, ensuring the safety of on-site personnel and equipment. It also allows for the collection and containment of leaked liquid acid and alkali chemicals, preventing their spread to surrounding work areas and the environment. The corrosion-resistant ground grating prevents leaked liquid acid and alkali chemicals from spreading to the safe house, ensuring the safety of evacuees. The nozzles and absorbers in this invention maximally limit the spread of soluble harmful gases such as ammonia and acid mist, ensuring the safety of personnel, equipment, and the environment in surrounding buildings. Furthermore, the operating handwheel and water supply valve are located inside the safe house, allowing for manual operation to maintain system functionality even in the event of power failure. Attached Figure Description

[0019] Figure 1 A schematic diagram of an emergency pre-response system for liquid acid and alkali chemical leaks at a nuclear power plant.

[0020] In the diagram: 1: Solar panel; 2: Forced air intake fan; 3: Safety house; 4: Pulley; 5: Domestic water supply pipe; 6: Guy wire; 7: Fire door; 8: Water supply valve; 9: Handwheel; 10: Equipment pit; 11: Forced exhaust fan; 12: Chemical storage room; 13: Acid mist absorber exhaust pipe; 14: Gas-liquid separator; 15: Acid mist absorber air inlet pipe; 16: Acid mist absorber; 17: Acid mist absorber water supply valve; 18: Acid mist absorber water supply pipe; 19: pH meter; 20: Sampling pump; 21: ... 21: Corrosion-resistant ground grating A; 22: Water level; 23: Acid mist absorber overflow pipeline; 24: Drain valve; 25: Leakage sump overflow pipeline; 26: Leakage sump drainage pump; 27: Drainage header; 28: Electric curtain track; 29: Sprinkler head; 30: Soft transparent plastic curtain; 31: Chemical storage tank; 32: Gas detection probe; 33: Chemical storage tank support foundation; 34: Dike; 35: Corrosion-resistant ground grating B; 36: Leakage sump; 37: Acid and alkali liquid immersion alarm; 38: Check valve. Detailed Implementation

[0021] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0022] like Figure 1 As shown, an emergency pre-response system for liquid acid and alkali chemical leaks in a nuclear power plant includes: a chemical storage tank 31 and an acid mist absorber 16 arranged inside a chemical storage building 12; a forced exhaust fan 11 arranged on the top of the chemical storage building 12; the chemical storage building 12 is connected to a safety house 3 via a fire door 7; the safety house 3 is equipped with a pulley 4, a domestic water supply pipe 5, a pull cable 6, a water supply valve 8, and a handwheel 9; and a solar panel 1 and a forced intake fan 2 are arranged on the roof of the safety house 3.

[0023] The chemical storage plant 12 has a corrosion-resistant floor grating A21 on its floor. The space beneath the grating A21 is divided into two pits: an equipment pit 10 and a leak pit 36. The leak pit overflow pipeline 25, leak pit drainage pump 26, and drainage header 27 are located in the equipment pit 10. Sprinkler nozzles 29 and acid / alkali liquid immersion alarms 37 are located in the leak pit 36. The medium in the leak pit 36 ​​can enter the leak pit drainage pump 26 and the leak pit overflow pipeline 25 through the through-wall drainage pipe inlet and overflow pipe inlet. The chemical storage tank support foundation 33 is also located in the leak pit 36 ​​and extends upwards to a position more than 2 meters above the ground, providing support for the chemical storage tank 31. The chemical storage tank support foundation 33 is resistant to corrosion from acid and alkali chemicals. On the ground, a dike 34 surrounds the chemical storage tank 31, the leak pit 36, and the corrosion-resistant ground grid A21. Above the dike 34 and the chemical storage tank 31, an electric curtain track 28 is arranged around the chemical storage tank 31. A soft transparent plastic curtain 30 is hung on the electric curtain track 28. Sprinklers 29 are arranged below the electric curtain track 28. When the gas detection probe 32 installed on the chemical storage tank support foundation 33 alarms, the electric curtain track 28 will drive the soft transparent plastic curtain 30 to surround the chemical storage tank 31, sprinklers 29, and other equipment. The sprinklers 29 will spray domestic water into the space inside the soft transparent plastic curtain 30, the dike 34, and the leak pit 36. When the automatic function fails, the soft transparent plastic curtain 30 can also be manually operated to close and spray water from inside the safety house 3 via handwheel 9, pull line 6, pulley 4, and water supply valve 8.

[0024] The acid mist absorber 16 is arranged above the equipment pit 10. The acid mist absorber exhaust pipe 13, acid mist absorber air inlet pipe 15, acid mist absorber overflow pipe 23, and acid mist absorber water supply pipe 18 are directly connected to the acid mist absorber 16. The acid mist absorber air inlet pipe 15 is directly connected to the indoor air outside, and is submerged below the water level 22 inside. Domestic water is used as the absorption medium in the acid mist absorber 16. A gas-water separator 14 is installed inside the acid mist absorber exhaust pipe 13. The acid mist absorber exhaust pipe 13 passes through the factory ceiling to reach the outside, and a forced exhaust fan 11 is installed at the end of the acid mist absorber exhaust pipe 13. The acid mist absorber 16 is equipped with an acid mist absorber water supply pipe 18, a drain pipe, and an acid mist absorber overflow pipe 23. During water supply, domestic water enters the acid mist absorber 16 through the acid mist absorber water supply pipe 18 and the acid mist absorber water supply valve 17. During drainage, water inside the acid mist absorber 16 enters the leakage sump overflow pipe 25 through the drain valve 24 and the check valve 38, and is then discharged into the neutralization tank by gravity. If the liquid level inside the acid mist absorber 16 is too high, it can also enter the leakage sump overflow pipe 25 through the acid mist absorber overflow pipe 23. A sampling device is also installed on the acid mist absorber 16. The medium inside the acid mist absorber 16 can be pumped by the sampling pump 20 to the pH meter 19 to detect the condition of the medium inside the acid mist absorber 16.

[0025] In the event of a rupture and leak in chemical storage tank 31, on-site personnel can enter the safety house 3 through the fire door 7 for refuge and escape. The leaked liquid acids and alkalis will flow into the leak pit 36 ​​through the corrosion-resistant ground grating B35. The gas detection probe 32 or the acid / alkali liquid immersion alarm 37 will trigger an alarm. The electric curtain track 28 will move a soft, transparent plastic curtain 30 around the chemical storage tank 31 to prevent the leaked acids and alkalis from splashing outside the containment dike 34 and causing injury to personnel or equipment. Once the soft, transparent plastic curtain 30 is in place, the water supply valve 8 will automatically open, and domestic water will enter the sprinkler head 29 through the domestic water supply pipe 5. Water will then be sprayed through the sprinkler head 29 into the leak area and the leak pit 36 ​​to dilute the acids and alkalis. The system absorbs ammonia, acid mist, and other substances that may be present in the air. After being diluted by water spray, the acid and alkali chemicals in the leak pit 36 ​​are discharged into the neutralization tank through the leak pit drainage pump 26 or the leak pit overflow pipeline 25 via the drainage header 27. During this process, if the electric curtain track 28 fails, the soft transparent plastic curtain 30 does not close properly, or the water supply valve 8 fails and does not connect to the domestic water supply, the on-site operators can manually operate the system using the handwheel 9 and the water supply valve 8 to ensure system functionality. The safety room 3 has a forced air intake fan 2 that runs continuously to maintain a slightly positive air pressure in the room, ensuring that toxic and harmful gases from the chemical storage plant 12 do not enter the safety room 3.

[0026] When the room is filled with harmful gases such as ammonia and acid mist, the gas can be discharged to the outside through the acid mist absorber 16. The forced exhaust fan 11 runs continuously to keep the acid mist absorber 16 under negative pressure. The harmful gas enters the bottom of the acid mist absorber 16 through the acid mist absorber inlet pipe 15. The harmful gas is absorbed by water in the acid mist absorber 16. The remaining gas is discharged to the outside through the acid mist absorber exhaust pipe 13 and the forced exhaust fan 11. During this process, when the discharged gas passes through the gas-water separator 14, the water mist in the discharged gas will be separated and condensed to prevent excessive humidity from damaging the forced exhaust fan 11. The condensed water returns to the acid mist absorber 16 by gravity. The acid mist absorber 16 has an automatic water replacement function. During operation, the sampling pump 20 starts intermittently to deliver water from the acid mist absorber 16 to the pH meter 19. When the pH meter 19 value exceeds the limit, the acid mist absorber water supply valve 17 and drain valve 24 automatically open to replace the water in the acid mist absorber 16, ensuring that the acid mist absorber 16 is continuously usable. When the liquid level in the acid mist absorber 16 is too high, the excess water can also overflow through the overflow pipe 23 to prevent the liquid level in the acid mist absorber 16 from entering the acid mist absorber exhaust pipe 13. The check valve 38 on the overflow pipe 23 can prevent the medium in the drain pipe from entering the acid mist absorber 16 due to negative pressure.

[0027] If the normal power supply to the system is lost for any reason, it can be supplied with power for a short time through solar panel 1 and battery to maintain some system functions under emergency conditions.

Claims

1. An emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants, characterized in that: Chemical storage tanks and acid mist absorbers are located inside the chemical storage building. Forced exhaust fans are located on the roof of the chemical storage building. The chemical storage building is connected to a safety room via fire doors. The safety room contains pulleys, domestic water supply pipes, guy wires, water supply valves, and handwheels. Forced intake fans are located on the roof of the safety room. The floor of the chemical storage building is covered with corrosion-resistant grating A. The space beneath the grating A is divided into equipment pits and leak pits. Overflow lines, drain pumps, and main drain pipes for the leak pits are located within the equipment pits. Sprinklers and acid / alkali immersion alarms are located within the leak pits. The support foundations for the chemical storage tanks are located within the leak pits. On the ground, a cofferdam surrounds the chemical storage tanks, leak pits, and corrosion-resistant grating A. Above the chemical storage tank, an electric curtain track is arranged around it, with soft, transparent plastic curtains hanging on the track. Sprayers are located below the track. The acid mist absorber is located above the equipment pit. The acid mist absorber exhaust pipe, air inlet pipe, overflow pipe, and water supply pipe are connected to the acid mist absorber. The air inlet pipe is directly connected to the indoor air, but submerged below the water level. A gas-liquid separator is installed inside the acid mist absorber exhaust pipe. The exhaust pipe passes through the factory ceiling to the outside. The acid mist absorber body is equipped with a water supply pipe, drain pipe, and overflow pipe. The medium inside the acid mist absorber is pumped into a pH meter to monitor the condition of the medium inside the absorber.

2. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: The roof of the safe house is equipped with solar panels.

3. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: The medium in the leaking sump enters the leaking sump drainage pump and the leaking sump overflow pipeline through the drain pipe inlet and overflow pipe inlet that pass through the wall.

4. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: The chemical storage tank support foundation is set inside the leak pit and extends upwards to a position more than 2 meters above the ground to provide support for the chemical storage tank. The chemical storage tank support foundation is resistant to corrosion from acid and alkali chemicals.

5. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: A forced exhaust fan is installed at the end of the exhaust pipe of the acid mist absorber.

6. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: Domestic water is used as the absorption medium in the acid mist absorber.

7. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: When replenishing water, domestic water enters the acid mist absorber through the acid mist absorber replenishment pipe and the acid mist absorber replenishment valve. When draining water, the water inside the acid mist absorber enters the overflow pipeline of the leak pit through the drain valve and check valve, and is discharged into the neutralization tank by gravity. When the liquid level inside the acid mist absorber is too high, it enters the overflow pipeline of the leak pit through the acid mist absorber overflow pipeline.

8. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: When a chemical storage tank ruptures and leaks, on-site personnel escape to the safety room through fire doors. The leaked liquid acids and alkalis flow into the leak pit through corrosion-resistant floor grating B. Gas detection probes or acid / alkali immersion alarms installed on the tank's support foundation trigger an alarm. An electric curtain track drives a soft, transparent plastic curtain to encircle the chemical storage tank, preventing the leaked chemicals from splashing outside the containment area. Once the curtain is in place, the water supply valve automatically opens, allowing domestic water to flow through the domestic water supply pipe into the sprinklers. Water is then sprayed into the leak area and leak pit to dilute the chemicals and absorb any ammonia or acid mist present in the air. After dilution by the sprayed water, the chemicals in the leak pit are discharged through a drain pump or overflow pipeline into a neutralization tank via a main drain pipe for neutralization.

9. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 8, characterized in that: If the electric curtain track fails, the soft transparent plastic curtain does not close properly, or the water supply valve fails and the domestic water is not connected properly, the on-site operator can manually operate the soft transparent plastic curtain to close and the sprinkler system from inside the safety room using handwheels, pull lines, pulleys, and the water supply valve. The safety room has a forced air intake fan that runs continuously to maintain a slightly positive air pressure inside the room, ensuring that toxic and harmful gases from the chemical storage plant do not enter the safety room.

10. The emergency pre-response system for liquid acid and alkali chemical leaks in nuclear power plants according to claim 1, characterized in that: When the room is filled with ammonia and acid mist, the harmful gases are discharged outdoors through the acid mist absorber. The forced exhaust fan runs continuously, maintaining negative pressure inside the absorber. The harmful gases enter the bottom of the absorber through the inlet pipe and are absorbed by water. The remaining gas is discharged outdoors through the exhaust pipe and the forced exhaust fan. During this process, the discharged gas passes through a gas-water separator, where water mist is separated and condensed to prevent excessive humidity from damaging the forced exhaust fan. The condensed water returns to the absorber by gravity. Inside, the acid mist absorber has an automatic water replacement function. During operation, the sampling pump starts intermittently to deliver water from the acid mist absorber to the pH meter. When the pH meter value exceeds the limit, the water supply valve and drain valve of the acid mist absorber automatically open to replace the water in the acid mist absorber, ensuring its continuous use. When the liquid level in the acid mist absorber is too high, the excess water overflows through the overflow pipeline to prevent the liquid level in the acid mist absorber from entering the exhaust pipe of the acid mist absorber. The check valve on the overflow pipeline prevents the medium in the drain pipeline from entering the acid mist absorber due to negative pressure.

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