CN-224232362-U - Passive containment heat export system

CN224232362UCN 224232362 UCN224232362 UCN 224232362UCN-224232362-U

Abstract

The utility model discloses a passive containment heat leading-out system which comprises a first water tank, a liquid level control valve, a second water tank and an ascending pipeline, wherein the first water tank, the liquid level control valve, the second water tank and the ascending pipeline are arranged outside a containment and are communicated, the containment penetrating piece and an in-shell heat exchanger are arranged in the containment, the ascending pipeline is communicated with the in-shell heat exchanger through the containment penetrating piece, the second water tank is communicated with the in-shell heat exchanger through the descending pipeline, the second water tank can accommodate cooling medium, the cooling medium flows through the descending pipeline from the second water tank to the in-shell heat exchanger and then returns to the second water tank through the containment penetrating piece and the ascending pipeline, and the first water tank can accommodate the cooling medium, and the cooling medium flows from the first water tank to the second water tank through the liquid level control valve. The passive containment heat conduction system provided by the embodiment of the utility model can fully utilize the enhancement factors of natural circulation capacity after flash evaporation, and meets the requirements of PCS system operation working conditions and heat carrying capacity after accidents.

Inventors

YANG CHANGJIANG
WU YUXIANG
JING CHUNNING
ZHENG YUNTAO
WANG GUANGFEI
WANG ZHENZHONG
YAO DI
Ni si

Assignees

中国核电工程有限公司

Dates

Publication Date: 20260512
Application Date: 20250325

Claims (11)

1. An passive containment heat removal system, the passive containment heat removal system comprising: the first water tank (1), the liquid level control valve (2), the second water tank (3) and the rising pipeline (4) are arranged outside the containment and communicated, A containment penetration (5) and an in-shell heat exchanger (6) disposed within the containment, the rising conduit (4) communicating with the in-shell heat exchanger (6) via the containment penetration (5); -a drop pipe (7), the second water tank (3) being in communication with the in-shell heat exchanger (6) via the drop pipe (7); The second water tank (3) can contain a cooling medium, and the cooling medium flows from the second water tank (3) through the descending pipeline (7) to the shell-in-shell heat exchanger (6) and returns to the second water tank (3) through the containment penetrating piece (5) and the ascending pipeline (4); the first water tank (1) can accommodate the cooling medium, which reaches the second water tank (3) from the first water tank (1) via the liquid level control valve (2).
2. Passive containment heat extraction system according to claim 1, characterized in that the bottom of the first water tank (1) is higher than the bottom of the second water tank (3) in a direction perpendicular to the ground.
3. The passive containment heat extraction system according to claim 1, characterized in that the diameter of the rising conduit (4) and the diameter of the falling conduit (7) satisfy 1.5 a≤b≤2.5 a, where a denotes the diameter of the falling conduit and b denotes the diameter of the rising conduit.
4. The passive containment heat extraction system according to claim 1, characterized in that the diameter of the containment penetration (5) and the diameter of the drop tube (7) satisfy a≤c≤1.5 a, where a denotes the diameter of the drop tube and c denotes the diameter of the containment penetration.
5. Passive containment heat extraction system according to claim 1, characterized in that the in-shell heat exchanger (6) comprises heat transfer tubes (61), the heat transfer tubes (61) having an inner diameter of 15-18 mm, the heat transfer tubes (61) having a wall thickness of 1.2-1.5 mm, the heat transfer tubes (61) having a length of 3-4.5 m.
6. Passive containment heat extraction system according to claim 1, characterized in that the length of the run-in section of the rising conduit (4) submerged in the second water tank (3) is such that 0.5 m≤h≤2m, where h denotes the length of the run-in section.
7. Passive containment heat extraction system according to claim 1, characterized in that the level of the cooling medium in the second water tank (3) is at a distance of 0.5m-1m from the outlet of the rising pipe (4) in the direction perpendicular to the ground.
8. The passive containment heat extraction system according to claim 6, characterized in that the height of the liquid level of the second water tank (3) is such that 1 m≤k≤2.5 m, where k represents the height of the liquid level of the second water tank (3).
9. The passive containment heat extraction system of claim 5 wherein the outlet temperature of the heat transfer tube (61) ranges from 102 ℃ to 112 ℃.
10. Passive containment heat extraction system according to claim 5, characterized in that the outlet temperature of the heat transfer tube (61) is lower than the saturation temperature of the cooling medium.
11. Passive containment heat extraction system according to claim 1, characterized in that the steam content of the cooling medium at the outlet of the rising pipe (4) is less than or equal to 0.023.

Description

Passive containment heat export system Technical Field The utility model relates to the technical field of nuclear power, in particular to a passive containment heat conduction system. Background When a pressurized water reactor nuclear power plant generates a primary loop coolant pipeline Break accident (LOCA, loss of Coolant Accident) or a secondary loop Steam pipeline Break accident (SLB, stem Line Break), a large amount of high-energy water or Steam enters the containment, so that the temperature and the pressure in the containment are increased. For LOCA, in addition to the short-term mass energy release, the long-term reactor residual power also needs to be discharged into the environment through the containment. Therefore, it is desirable to provide a containment heat release and pressure relief system to remove heat stored within the containment and control the temperature and pressure within the containment. Systems for heat removal from a containment have either active containment spray systems or passive containment heat removal systems. At present, as shown in fig. 1, a passive containment heat conduction system (PCS, passive Containment Cooling System) adopted by a pressurized water reactor nuclear power station comprises a heat exchanger 101, an external high-level water tank 102 (PCS water tank), a connected pipeline valve, a steam-water separation device and the like, wherein water is used as a heat medium, and passive natural circulation flow cooling is realized by means of fluid density difference in an ascending section and a descending section in the system. The heat exchangers and the water tanks outside the shell are designed in multiple rows and are symmetrically arranged along the containment, and the pipelines in each row of systems are arranged as short as possible so as to reduce the circulating resistance of the systems and increase the heat carrying capacity of the systems. When the temperature of the PCS water tank is increased to be close to the saturation temperature, the water in the rising section of the system is flashed to form two-phase natural circulation. However, the PCS water tank has a large volume because of the need to meet the water storage requirement of long-term heat after an accident. For a million kilowatt-level pressurized water reactor unit, 3 PCS water tanks are designed, and the water storage capacity of a single water tank is about 1000m 3. Since natural circulation requires the PCS tank to be disposed at a higher level outside the containment, this places high demands on the tank and support structure. The outer water tank of the PCS system is arranged on the outer shell of the double-layer containment in a cantilever mode, the structural design requirement is high, and the construction difficulty is high. For a reactor designed by a single-layer containment, the technical scheme that the PCS water tank is hung on the outer wall surface of the single-layer containment is difficult to realize because the containment needs to be prestressed and tensioned after the structural construction is completed. In addition, patent CN102637464 discloses a reinforced heat exchange device of a double-layer concrete containment passive heat export system, which comprises a heat exchanger group, a rising pipe, a falling pipe, a heat exchange water tank and a steam-water separator. The working medium in the heat exchanger is heated and expanded to flow upwards, and enters a steam-water separator in the heat exchange water tank outside the containment, and the working medium with low temperature and high density flows downwards from the steam-water separator in the heat exchange water tank outside the containment along a descending pipe to enter an internal heat exchanger after cooling, and the whole process depends on natural circulation to complete a heat leading-out function. The above-described devices do not satisfy the discharge of the residual power of the reactor during the long-term phase. Disclosure of Invention The present utility model aims to solve the above technical problems. To this end, a first object of the present utility model is to propose a passive containment heat removal system that accommodates sufficient cooling medium to meet long term post-accident heat requirements, thus meeting post-accident PCS system operating conditions and heat carrying capacity requirements. To achieve the above object, a first aspect of the present utility model provides a passive containment heat extraction system, comprising: The first water tank, the liquid level control valve, the second water tank and the rising pipeline are arranged outside the containment and communicated, The shell heat exchanger comprises a containment penetrating piece and an in-shell heat exchanger arranged in the containment, wherein the rising pipeline is communicated with the in-shell heat exchanger through the containment penetrating piece; The second water tank is communicated with the