Long-effectiveness passive containment cooling system

Abstract

The invention discloses a long-effectiveness passive containment cooling system. The heat of water in a heat exchange pool can be transmitted into air between a containment and a concrete shielding layer through evaporation of the water in the heat exchange pool and / or heat exchange of a heat exchange pipe component, the heat can be taken away by air convection between an air inlet and an air outlet, and a water-supplementing device of a containment water-supplementing pool can maintain that the liquid level of the heat exchange pool is basically not changed. By implementation of the long-effectiveness passive containment cooling system provided by the invention, the hidden danger of the containment structural strength and stability can be eliminated, the capacity of the containment water-supplementing pool is increased and the extreme event-resisting ability of the containment is improved; heat exchange power is obviously increased and safe reliability is improved; and temperature reduction and pressure reduction of the containment are effectively realized, so that the integrity of the containment is guaranteed.

Description

technical field [0001] The invention relates to the field of nuclear power, in particular to a long-term passive containment cooling system (PCCS). Background technique [0002] Due to the unreasonable structural design of the passive containment cooling system of the existing nuclear power plant, there are mainly the following technical problems: [0003] 1. The structure carrying a huge water storage tank on the top of the containment can easily lead to structural damage and loss of safety functions in extreme events such as strong earthquakes, sea waves, and tornadoes. [0004] In addition, in this method, the cooling water source is located in the water storage tank above the containment, and the water tank is equipped with redundant liquid level measurement channels and alarms to monitor the water level of the water tank, while redundant temperature measurement channels are provided to monitor temperature and Alarm at low temperature to prevent water from freezing. To...

AI Technical Summary

Problems solved by technology

In the normal operation of the nuclear power plant, the recirculation loop maintains the normal state of the water tank; in the event of an accident, the recirculation loop is a non-safety system. If the nuclear power plant is located in a low temperature zone, the water in the water tank may freeze. The water in the sprinkler pipes may freeze, preventing an effective safety shower

[0005] 2. In the passive way of spraying and cooling the outer wall of the steel containment by relying on the low-temperature water in the passive containment cooling water tank (PCCWST) after the accident of the existing nuclear power plant, the water volume in the water tank is only sufficient for a short time (such as : 72 hours, the containment structure is not enough to bear a larger load) functional requirements

In the case of extreme natural disasters, such as the Fukushima nuclear accident, the AC power supply inside and outside the plant is completely lost for a long time. When the water tank of PCCWST is emptied, there is no power source to drive the recirculation pump to replenish water

If only relying on air convection to cool the outer wall of the containment is not enough to discharge the waste heat in the reactor, the high pressure inside the containment will cause the containment to rupture, resulting in a sharp deterioration in the consequences of the accident

[0006] In addition, in this method, a layer of water film is established on the outer wall of the steel containment vessel, and the evaporation and convection of the water film are used to remove heat. Since the pressure peak in the containment vessel often reaches the initial stage of the accident, that is, the accident The initial period is the period when effective cooling is most needed, and the delay time for establishing a water film in PCCS based on the experiment is as long as 337 seconds, and the timeliness of heat exchange is insufficient; at the same time, according to the experiments of Westinghouse Corporation in the United States, the coverage rate of water film establishment, Heat removal capability has not been fully verified so far

[0007] It can be seen that the containment heat capacity and heat removal are the bottleneck problems faced by the passive PWR nuclear power plant to further increase the power. The volume of the water storage tank and other methods can no longer meet the functional requirements under high-power conditions, which is not conducive to the overall economy and safety of the power plant

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