CN113096837A - Passive residual heat removal system of reactor - Google Patents

Abstract

The invention discloses a reactor passive residual heat removal system, which comprises a water-cooled tube, a pressure vessel, an air cooler, an adjusting valve and a chimney, wherein the water-cooled tube is connected with the pressure vessel; the water-cooled tube twines on pressure vessel's outer wall, and the export of water-cooled tube is linked together through the entry of air cooler and governing valve, and the export of governing valve is linked together with the entry of water-cooled tube, and inside the air cooler was located the chimney, and the import department of chimney bottom installs the inlet air valve group, and the heat exchange efficiency of this system is high, and can improve pressure vessel cavity concrete's life.

Description

Passive residual heat removal system of reactor

Technical Field

The invention belongs to the field of passive waste heat derivation of reactors, and relates to a passive waste heat removal system of a reactor.

Background

The current third-generation and fourth-generation advanced reactors all require a safety-level passive waste heat removal system for conducting waste heat derivation without depending on active equipment in an emergency state, so that the fault safety of the reactors is improved.

A safety-level passive waste heat discharge system adopted by the pressurized water reactor leads out coolant from a loop heat pipe section, cools and cools the coolant, and returns the coolant to the loop heat pipe section. Because the passive residual heat removal system of the pressurized water reactor is communicated with a primary circuit, the pressure of the primary circuit of the pressurized water reactor generally exceeds 15MPa, the required pressure-bearing grade of a heat transfer pipe is high, the material needs to be made of special materials, and the cost is very high; due to the fact that the equipment range of the pressure boundary of the primary circuit is enlarged, damage of the heat transfer pipe can cause small LOCA of the primary circuit, and uncertainty risks are increased.

The safety-level passive residual heat removal system of the high-temperature gas cooled reactor adopts the idea of radiation heat exchange, namely, the outer surface of a reactor pressure vessel is not provided with a heat insulation layer, a metal heat transfer pipe is arranged outside the reactor pressure vessel, and heat exchange is carried out by radiation and natural convection between the outer surface of the reactor pressure vessel and the metal heat transfer pipe, so that the reactor core residual heat is led out. Although the passive residual heat removal system avoids the high cost of the pressurized water reactor residual heat removal system and the risk of a primary circuit LOCA, the outer surface of a pressure container is about 250 ℃, the efficiency of a radiation and natural convection heat exchange mode is too low, and the residual heat removal capacity of a reactor core is influenced; the radiation heat exchange mode can form a high-temperature environment with the temperature of more than 150 ℃ in the pressure container cavity, and the long-time high-temperature effect can cause the high-temperature aging of the concrete in the pressure container cavity, thereby influencing the service life of the concrete.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a reactor passive residual heat removal system which is high in heat exchange efficiency and capable of prolonging the service life of pressure vessel cavity concrete.

In order to achieve the aim, the passive waste heat discharge system of the reactor comprises a water-cooled tube, a pressure vessel, an air cooler, a regulating valve and a chimney;

the water-cooled pipe is wound on the outer wall of the pressure container, the outlet of the water-cooled pipe is communicated with the inlet of the regulating valve through an air cooler, the outlet of the regulating valve is communicated with the inlet of the water-cooled pipe, the air cooler is positioned inside the chimney, and the inlet air valve group is installed at the inlet of the bottom of the chimney.

The water cooling pipe is spiral.

The outlet of the water cooling pipe is communicated with the inlet of the air cooler through a flowmeter.

The expansion tank is also included, and the outlet of the expansion tank is communicated with the inlet of the regulating valve.

The expansion water tank is filled with water, and nitrogen is filled between the water surface and the inner wall of the top of the expansion water tank.

The outer wall of the water-cooling pipe is wrapped with a heat-insulating layer.

The air cooler is positioned above the pressure vessel.

The inlet air valve group is formed by connecting a plurality of air valves in parallel.

The invention has the following beneficial effects:

when the passive residual heat removal system for the reactor is in specific operation, the heat in the pressure vessel of the reactor is transferred to cold water in the water cooling pipe by the water cooling pipe in a heat conduction mode, so that the cold water in the water cooling pipe absorbs heat to become hot water, then the hot water is sent into the air cooler for cooling, and finally the hot water is sent into the water cooling pipe, so that the residual heat removal efficiency and capacity are improved, the problem of high-temperature aging of the concrete in the cavity of the pressure vessel is avoided, and the service life of the concrete in the cavity of the pressure vessel is prolonged. Meanwhile, the whole system is not communicated with a loop, so that the pressure bearing grade and the material requirement of the heat transfer pipe can be reduced, the cost is saved, the small LOCA of the loop caused by the damage of the heat transfer pipe is avoided, and the operation risk of the system is reduced.

Drawings

FIG. 1 is a schematic structural view of the present invention.

Wherein, 1 is a pressure vessel, 2 is an insulating layer, 3 is a water cooling pipe, 4 is a flow meter, 5 is a chimney, 6 is an air cooler, 7 is an inlet air valve, 8 is an expansion water tank, 8-1 is nitrogen, 8-2 is water, and 9 is an adjusting valve.

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

There is shown in the drawings a schematic block diagram of a disclosed embodiment in accordance with the invention. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, according to actual needs.

Referring to fig. 1, the passive reactor waste heat removal system of the present invention includes a pressure vessel 1, a thermal insulation layer 2, a water cooling pipe 3, a flow meter 4, a chimney 5, an air cooler 6, an inlet air valve 7, an expansion water tank 8, and an adjusting valve 9;

the water-cooling pipe 3 is a copper pipe, the water-cooling pipe 3 is spirally wound on the outer wall of the pressure container 1, the outlet of the water-cooling pipe 3 is communicated with the inlet of the regulating valve 9 through the flowmeter 4 and the air cooler 6, the outlet of the expansion water tank 8 is communicated with the inlet of the regulating valve 9, and the outlet of the regulating valve 9 is communicated with the inlet of the water-cooling pipe 3; water 8-2 is filled in the expansion water tank 8, and nitrogen 8-1 is filled between the water surface and the inner wall of the top of the expansion water tank 8;

the outer wall of water-cooled tube 3 is wrapped up by heat preservation layer 2, and when the work is carried out, water flow at the outlet of water-cooled tube 3 is detected by flow meter 4, and the flow of water entering water-cooled tube 3 is controlled by regulating valve 9.

The air cooler 6 is positioned in the chimney 5, and the position of the air cooler 6 is higher than that of the pressure container 1. An inlet air valve group 7 is arranged at the inlet of the bottom of the chimney 5, and the inlet air valve group 7 is formed by connecting a plurality of air valves in parallel.

The expansion water tank 8 is arranged at the upstream of the regulating valve 9, nitrogen 8-1 in the expansion water tank 8 is used for maintaining the pressure of the system at 1.5-2MPa, and water 8-2 in the expansion water tank 8 is used for compensating small leakage, expansion caused by heat and contraction caused by cold of the system.

The specific working process of the invention is as follows:

when the passive residual heat removal system is not used, the inlet air valve 7 and the regulating valve 9 are completely closed, no cooling water flows in the system, water 8-2 in the expansion water tank 8 is used for compensating small leakage and expansion and contraction of the system, and nitrogen 8-1 in the expansion water tank 8 is used for maintaining the pressure of the system at 1.5-2 MPa.

When the passive residual heat removal system is put into use, the inlet air valve 7 and the regulating valve 9 are automatically opened, hot water output by the water-cooled tube 3 enters the air cooler 6, cold air in the chimney 5 is heated by the hot water in the air cooler 6 and then rises to discharge the chimney 5, a suction effect is formed, the cold air is sucked into the chimney 5 from the inlet air valve 7, the hot water in the air cooler 6 releases heat and then becomes cooling water, and then the cooling water enters the water-cooled tube 3 to absorb decay heat conducted by the reactor pressure vessel 1 so as to lead out the residual heat of the reactor core.

The opening degree of the inlet air valve 7 is adjusted, so that the temperature of water entering the water cooling pipe 3 is higher than 80 ℃, the opening degree of the adjusting valve 9 is adjusted to control the waste heat discharge capacity of the reactor core, and the phenomenon that the temperature of a primary loop of the reactor is too fast is avoided.

Claims (8)

1. A reactor passive residual heat removal system is characterized by comprising a water cooling pipe (3), a pressure container (1), an air cooler (6), a regulating valve (9) and a chimney (5);

the water cooling pipe (3) is wound on the outer wall of the pressure container (1), the outlet of the water cooling pipe (3) is communicated with the inlet of the regulating valve (9) through the air cooler (6), the outlet of the regulating valve (9) is communicated with the inlet of the water cooling pipe (3), the air cooler (6) is positioned inside the chimney (5), and the inlet of the bottom of the chimney (5) is provided with the inlet air valve group (7).

2. The reactor passive residual heat removal system according to claim 1, characterized in that the water cooling tubes (3) are helical.

3. The reactor passive residual heat removal system according to claim 1, characterized in that the outlet of the water cooling pipe (3) is communicated with the inlet of the air cooler (6) through a flowmeter (4).

4. The reactor passive residual heat removal system according to claim 1, further comprising an expansion tank (8), wherein an outlet of the expansion tank (8) is communicated with an inlet of the regulating valve (9).

5. The reactor passive residual heat removal system according to claim 4, characterized in that the expansion tank (8) is filled with water, and nitrogen (8-1) is filled between the water surface and the inner wall of the top of the expansion tank (8).

6. The passive residual heat removal system of the reactor according to claim 1, characterized in that the outer wall of the water cooling tube (3) is wrapped with an insulating layer (2).

7. The reactor passive residual heat removal system according to claim 1, wherein the air cooler (6) is located at a higher position than the pressure vessel (1).

8. The reactor passive residual heat removal system according to claim 1, characterized in that the inlet air valve group (7) is formed by connecting a plurality of air valves in parallel.

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