A reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure

Abstract

The present invention discloses a reactor air-cooled residual heat removal system with a pressure vessel having a double-layer structure, which includes an inner main pressure vessel, an outer auxiliary pressure vessel, a heat insulation layer and a plurality of residual heat removal components; the outer auxiliary pressure vessel is sleeved on the outer wall of the inner main pressure vessel, and a cavity is formed between the outer auxiliary pressure vessel and the inner main pressure vessel, wherein the cavity is divided into a plurality of interlayer chambers; the heat insulation layer is sleeved on the outer wall of the outer auxiliary pressure vessel; one interlayer chamber corresponds to one residual heat removal component, and this system can solve the problem of high-temperature aging of the concrete in the pressure vessel chamber.

Description

Technical Field

[0001] The present invention belongs to the field of nuclear reactor pressure vessels and residual heat removal, and relates to a reactor air-cooled residual heat removal system with a pressure vessel having a double-layer structure. Background Art

[0002] Currently, third and fourth generation advanced reactors all require a safety-class passive residual heat removal system, which is used to remove residual heat without relying on active equipment in an emergency state, thereby improving the fail-safe performance of the reactor.

[0003] The safety-class passive residual heat removal system adopted by a pressurized water reactor draws coolant from the hot leg of the primary loop, cools it down, and then returns it to the hot leg of the primary loop. Since the passive residual heat removal system of the pressurized water reactor is connected to the primary loop, and the pressure of the primary loop of a general pressurized water reactor exceeds 15 MPa, the pressure-bearing grade required for the heat transfer tubes is high, and special materials are needed for manufacturing, resulting in high costs; since the equipment range of the primary loop pressure boundary is increased, the breakage of the heat transfer tubes can trigger a small LOCA in the primary loop, increasing the risk of uncertainty.

[0004] The safety-class passive residual heat removal system of a high-temperature gas-cooled reactor adopts the idea of radiative heat transfer, that is, there is no insulation layer on the outer surface of the reactor pressure vessel, and metal heat transfer tubes are arranged outside the reactor pressure vessel. Heat transfer is carried out by radiation and natural convection between the outer surface of the reactor pressure vessel and the metal heat transfer tubes, so as to export the core residual heat. Although this passive residual heat removal system avoids the high cost of the pressurized water reactor residual heat removal system and the risk of primary loop LOCA, the outer surface of the pressure vessel is generally about 250 °C, and the efficiency of the radiative and natural convection heat transfer method is too low, affecting the core residual heat export capacity; the radiative heat transfer method will form a high-temperature environment above 150 °C in the pressure vessel chamber, and the long-term high-temperature effect will cause high-temperature aging of the concrete in the pressure vessel chamber, affecting the concrete life. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned disadvantages of the prior art, and provide a reactor air-cooled residual heat removal system with a pressure vessel having a double-layer structure, which can solve the problem of high-temperature aging of the concrete in the pressure vessel chamber.

[0006] To achieve the above purpose, the reactor air-cooled residual heat removal system with a pressure vessel having a double-layer structure according to the present invention includes an inner main pressure vessel, an outer auxiliary pressure vessel, a thermal insulation layer and a plurality of residual heat removal components;

[0007] The outer auxiliary pressure vessel is sleeved on the outer wall of the inner main pressure vessel, and a cavity is formed between the outer auxiliary pressure vessel and the inner main pressure vessel, wherein the cavity is divided into a plurality of interlayer chambers;

[0008] The thermal insulation layer is sleeved on the outer wall of the outer auxiliary pressure vessel;

[0009] One interlayer chamber corresponds to one residual heat removal component. Each residual heat removal component includes a cold air input pipeline, a containment outlet isolation valve, a chimney inlet air valve, a chimney, a vacuum isolation valve, and a vacuum device. Among them, a cold air inlet air valve and a containment inlet isolation valve are arranged on the cold air input pipeline. The cold air input pipeline is connected to the inlet at the bottom of the interlayer chamber. The outlet at the top of the interlayer chamber is divided into two paths. One path is connected to the chimney through the containment outlet isolation valve, and the other path is connected to the vacuum device through the vacuum isolation valve.

[0010] A number of transverse supports are arranged between the inner side wall of the outer auxiliary pressure vessel and the outer wall of the inner main pressure vessel.

[0011] A longitudinal support is arranged between the inner wall at the bottom of the outer auxiliary pressure vessel and the outer wall at the bottom of the inner main pressure vessel.

[0012] An inspection manhole is arranged on the outer wall of the outer auxiliary pressure vessel.

[0013] The positions of the chimney inlet air valve and the chimney are higher than those of the inner main pressure vessel and the outer auxiliary pressure vessel.

[0014] The inner main pressure vessel, the outer auxiliary pressure vessel, the transverse support, the longitudinal support, the inspection manhole, the interlayer chamber, the thermal insulation layer, the containment inlet isolation valve, the containment outlet isolation valve, the vacuum isolation valve, and the vacuum device are located inside the containment.

[0015] A fan is arranged at the inlet of the cold air input pipeline.

[0016] A chimney inlet air valve is arranged at the inlet of the chimney.

[0017] Each interlayer chamber is evenly distributed circumferentially.

[0018] The present invention has the following beneficial effects:

[0019] When the reactor with a double-layer structure pressure vessel of the present invention is in specific operation, in the case of an emergency condition of the reactor, the present invention is put into use. At this time, the vacuum device is shut down, the vacuum isolation valve is closed, and the interlayer chamber starts to enter air and becomes at atmospheric pressure. The cold air inlet air valve, the containment inlet isolation valve, the containment outlet isolation valve, and the chimney inlet air valve are all automatically opened. The cold air is heated in the interlayer chamber, forms a natural circulation flow into the chimney, and flows upward to form a suction effect, so that the cold air continuously enters the interlayer chamber to cool the inner main pressure vessel and take out the core residual heat, avoiding the problem of high-temperature aging of the concrete in the pressure vessel chamber. The structure is simple, the operation is convenient, and the practicability is extremely strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural view of the present invention.

[0021] Wherein, 1 is the inner main pressure vessel, 2 is the outer auxiliary pressure vessel, 2-1 is the transverse support, 2-2 is the longitudinal support, 2-3 is the maintenance manhole, 2-4 is the interlayer chamber, 3 is the thermal insulation layer, 4 is the containment, 5 is the cold air inlet air valve, 6 is the containment inlet isolation valve, 7 is the containment outlet isolation valve, 8 is the induced draft chimney inlet air valve, 9 is the induced draft chimney, 10 is the vacuum isolation valve, and 11 is the vacuum device. DETAILED DESCRIPTION OF THE INVENTION

[0022] In order to enable those skilled in the art of the present technology to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, 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 invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concepts disclosed in the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

[0023] The schematic structural views according to the disclosed embodiments of the present invention are shown in the drawings. These figures are not drawn to scale, and for the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are only exemplary. In practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art can design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0024] Refer to Figure 1 , the reactor air-cooled residual heat removal system with a double-layer structure pressure vessel according to the present invention includes an outer auxiliary pressure vessel 2, an inner main pressure vessel 1, a thermal insulation layer 3, a containment 4, and several residual heat removal components;

[0025] The outer auxiliary pressure vessel 2 is sleeved on the outer wall of the inner main pressure vessel 1, and a cavity is formed between the outer auxiliary pressure vessel 2 and the inner main pressure vessel 1. Among them, the cavity is divided into several interlayer chambers 2-4, and each interlayer chamber 2-4 is evenly distributed in the circumferential direction.

[0026] The thermal insulation layer 3 is sleeved on the outer wall of the outer auxiliary pressure vessel 2. Among them, several transverse supports 2-1 are arranged between the inner side wall of the outer auxiliary pressure vessel 2 and the outer wall of the inner main pressure vessel 1, and a longitudinal support 2-2 is arranged between the inner wall at the bottom of the outer auxiliary pressure vessel 2 and the outer wall at the bottom of the inner main pressure vessel 1. An inspection manhole 2-3 is arranged on the outer wall of the outer auxiliary pressure vessel 2;

[0027] One interlayer chamber 2-4 corresponds to one waste heat discharge component. Each waste heat discharge component includes a cold air input pipeline, a containment outlet isolation valve 7, a chimney inlet air valve 8, a chimney 9, a vacuum isolation valve 10 and a vacuum device 11. Among them, a cold air inlet air valve 5 and a containment inlet isolation valve 6 are arranged on the cold air input pipeline. The cold air input pipeline is connected to the inlet at the bottom of the interlayer chamber 2-4. The outlet at the top of the interlayer chamber 2-4 is divided into two paths. One path is connected to the chimney 9 through the containment outlet isolation valve 7 and the chimney inlet air valve 8, and the other path is connected to the vacuum device 11 through the vacuum isolation valve 10.

[0028] The inner main pressure vessel 1, the outer auxiliary pressure vessel 2, the transverse support 2-1, the longitudinal support 2-2, the inspection manhole 2-3, the interlayer chamber 2-4, the thermal insulation layer 3, the containment inlet isolation valve 6, the containment outlet isolation valve 7, the vacuum isolation valve 10 and the vacuum device 11 are located inside the containment 4.

[0029] The positions of the chimney inlet air valve 8 and the chimney 9 are higher than those of the inner main pressure vessel 1 and the outer auxiliary pressure vessel 2.

[0030] The specific working process of the present invention is as follows:

[0031] During normal operation of the reactor, the inspection manhole 2-3, the cold air inlet air valve 5, the containment inlet isolation valve 6, the containment outlet isolation valve 7 and the chimney inlet air valve 8 are all in the closed state, and the present invention does not operate. The vacuum device 11 and the vacuum isolation valve 10 are in the automatic mode. The vacuum device 11 starts and stops automatically according to the vacuum degree of the interlayer chamber 2-4, and the vacuum isolation valve 10 opens or closes automatically according to the start and stop of the vacuum device 11, automatically maintaining the interlayer chamber 2-4 in a vacuum state, with an absolute pressure value less than 5 KPa, significantly reducing the heat dissipation of the reactor pressure vessel, and at the same time avoiding the radiation risk caused by the accumulation of neutron-activated air inside the waste heat discharge system.

[0032] There is only a very small amount of air inside the vacuum state interlayer chamber 2-4, and the concentration of radioactive activation products generated by neutron irradiation during operation of the reactor is extremely low. And due to the operation of the vacuum device 11 and the vacuum isolation valve 10, the extremely small amount of radioactive products generated by activation are discharged into the inside of the containment 4 and adsorbed and purified by the air purification system inside the containment 4, and will not cause radioactive release into the atmosphere.

[0033] The interlayer chamber 2-4 in a vacuum state simultaneously serves as the thermal insulation layer 3 to reduce the heat dissipation of the inner main pressure vessel 1 and reduce the thermal stress formed by the inner main pressure vessel 1 and the outer auxiliary pressure vessel 2.

[0034] When the reactor is shut down for normal maintenance, the vacuum pumping device 11 is out of service, the vacuum isolation valve 10 is closed, and the interlayer chamber 2-4 is in an atmospheric pressure state. The cold air inlet air valve 5, the containment inlet isolation valve 6, the containment outlet isolation valve 7, and the chimney inlet air valve 8 are all in the open state. The cold air output from the cold air input pipeline enters the interlayer chamber 2-4 for heat exchange and temperature rise, and then is discharged through the chimney 9. When the temperature in the interlayer chamber 2-4 drops to the working allowable temperature, the maintenance manhole 2-3 is opened to repair the inner main pressure vessel 1, the outer auxiliary pressure vessel 2, and their internal components.

[0035] When the reactor needs to put into operation the residual heat removal system under emergency conditions, the vacuum pumping device 11 is out of service, the vacuum isolation valve 10 is closed, and the interlayer chamber 2-4 starts to admit air and becomes in an atmospheric pressure state. The cold air inlet air valve 5, the containment inlet isolation valve 6, the containment outlet isolation valve 7, and the chimney inlet air valve 8 all open automatically. The cold air is heated in the interlayer chamber 2-4, forms a natural circulation flow into the chimney 9, and flows upward to form a suction effect, so that the cold air continuously enters the interlayer chamber 2-4 to cool the inner main pressure vessel 1 and carry out the residual heat of the reactor core. A temporary fan can be added at the inlet of the cold air inlet air valve 5 to force-feed air into the interlayer chamber 2-4, so that the residual heat removal system is in a forced operation state.

[0036] Finally, it should be noted that for a pressurized water reactor, the present invention is no longer connected to the primary loop, which can reduce the pressure-bearing grade and material requirements of the heat transfer tubes, save costs, and at the same time avoid a small LOCA in the primary loop caused by the breakage of the heat transfer tubes, reducing the system operation risk.

Claims

1. A reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure, characterized in that, it includes an inner main pressure vessel (1), an outer auxiliary pressure vessel (2), a heat insulation layer (3) and a number of residual heat removal components; The outer auxiliary pressure vessel (2) is sleeved on the outer wall of the inner main pressure vessel (1), and a cavity is formed between the outer auxiliary pressure vessel (2) and the inner main pressure vessel (1), wherein the cavity is divided into a number of interlayer chambers (2-4); The heat insulation layer (3) is sleeved on the outer wall of the outer auxiliary pressure vessel (2); One interlayer chamber (2-4) corresponds to one residual heat removal component, and each residual heat removal component includes a cold air input pipeline, a containment outlet isolation valve (7), a chimney inlet air valve (8), a chimney (9), a vacuum isolation valve (10) and a vacuum device (11). Among them, a cold air inlet air valve (5) and a containment inlet isolation valve (6) are arranged on the cold air input pipeline. The cold air input pipeline is connected to the inlet at the bottom of the interlayer chamber (2-4). The outlet at the top of the interlayer chamber (2-4) is divided into two paths. One path is connected to the chimney (9) through the containment outlet isolation valve (7), and the other path is connected to the vacuum device (11) through the vacuum isolation valve (10).

2. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, characterized in that, A number of transverse supports (2-1) are arranged between the inner side wall of the outer auxiliary pressure vessel (2) and the outer wall of the inner main pressure vessel (1).

3. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, characterized in that, A longitudinal support (2-2) is arranged between the inner wall at the bottom of the outer auxiliary pressure vessel (2) and the outer wall at the bottom of the inner main pressure vessel (1).

4. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, characterized in that, An inspection manhole (2-3) is arranged on the outer wall of the outer auxiliary pressure vessel (2).

5. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, characterized in that, The position of the chimney inlet air valve (8) and the chimney (9) is higher than that of the inner main pressure vessel (1) and the outer auxiliary pressure vessel (2).

6. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 4, characterized in that, It further includes a containment (4); the inner main pressure vessel (1), the outer auxiliary pressure vessel (2), the inspection manhole (2-3), the interlayer chamber (2-4), the heat insulation layer (3), the containment inlet isolation valve (6), the containment outlet isolation valve (7), the vacuum isolation valve (10) and the vacuum device (11) are located inside the containment (4).

7. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, characterized in that, A fan is arranged at the inlet of the cold air input pipeline.

8. The reactor air-cooled residual heat removal system with a pressure vessel of double-layer structure according to claim 1, It is characterized in that An air extraction chimney inlet air valve (8) is provided at the inlet of the air extraction chimney (9).

9. The reactor air-cooled residual heat removal system with a pressure vessel having a double-layer structure according to claim 1, It is characterized in that Each interlayer chamber (2-4) is evenly distributed circumferentially.

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