Nuclear power primary loop static exhaust method and system

Abstract

The invention discloses a nuclear power primary loop static exhaust method and system. The nuclear power primary loop static exhaust method comprises the following steps: S1, remotely opening a first isolation valve and a second isolation valve on a communicating pipeline between a top isolation valve of a reactor pressure vessel and a nuclear island exhaust and drainage system; s2, opening a top isolating valve of the reactor pressure vessel and a primary loop exhaust isolating valve on the communicating pipeline on site, and then slowly opening a primary loop dynamic exhaust regulating valve on the communicating pipeline to exhaust with throttling sound; and S3, continuous water flow is discharged from the primary loop dynamic exhaust regulating valve, and the primary loop dynamic exhaust regulating valve is closed after no bubble exists in the water flow. According to the static exhaust method for the nuclear power primary loop, non-condensed gas of the nuclear power primary loop is effectively exhausted, and the gas content requirement is met; the device is suitable for static exhaust of a 27bar. G high-pressure platform, and the exhaust effect is good; the overhaul period is greatly shortened, and the economic benefit of the power station is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant operation control, and in particular to a static exhaust method and system for a nuclear power primary circuit. Background Art

[0002] The primary circuit of nuclear power is one of the most critical systems in a nuclear power plant, mainly composed of reactors, main pumps, steam generators and other equipment. High-temperature, high-pressure, radioactive coolant flows in the primary circuit. Its main function is to transfer the heat generated by the reactor to the steam generator to generate steam to drive the steam turbine to generate electricity. Static exhaust of the primary circuit of nuclear power is an important link in the operation of nuclear power plants. Its purpose is to remove the gas in the primary circuit system: during the water filling and temperature rise process of the primary circuit system, some gas will dissolve in the coolant or remain in the high points and dead corners of the system. These gases may affect the heat transfer efficiency of the system and may even cause local overheating and equipment damage. Through dynamic and static exhaust, these gases can be discharged from the system to ensure the normal operation of the primary circuit. The pressure of the primary circuit system is determined by the temperature and volume of the coolant. If there is too much gas in the system, it will cause pressure fluctuations and affect the stability of the system. Through static exhaust, the pressure of the system can be adjusted in time to keep it within the design range. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a nuclear power primary circuit static exhaust method and a nuclear power primary circuit static exhaust system.

[0004] The technical solution adopted by the present invention to solve the technical problem is: to provide a static exhaust method for a nuclear power primary circuit, comprising the following steps:

[0005] S1, remotely open the first isolation valve and the second isolation valve on the connecting pipeline between the top isolation valve of the reactor pressure vessel and the nuclear island exhaust and drain system;

[0006] S2. After opening the top isolation valve of the reactor pressure vessel and the primary exhaust isolation valve on the connecting pipeline on site, slowly open the primary dynamic exhaust regulating valve on the connecting pipeline to exhaust the gas, accompanied by a throttling sound;

[0007] Wherein, the primary exhaust isolation valve and the primary dynamic exhaust regulating valve are sequentially located on the side of the second isolation valve away from the first isolation valve; the opening of the primary dynamic exhaust regulating valve is a small opening that does not leave the closing limit;

[0008] S3, after the primary-loop dynamic exhaust regulating valve discharges a continuous water flow and there are no bubbles in the water flow, the primary-loop dynamic exhaust regulating valve is closed.

[0009] Preferably, there are two parallel connecting branches between the top isolation valve and the primary exhaust isolation valve, and each of the connecting branches is provided with the first isolation valve and the second isolation valve;

[0010] In step S1, the first isolation valve and the second isolation valve on one or two of the connecting branches are opened.

[0011] Preferably, the nuclear power primary circuit static exhaust method further comprises the following steps:

[0012] S4. Close the top isolation valve and the primary exhaust isolation valve in sequence.

[0013] Preferably, the nuclear power primary circuit static exhaust method further comprises the following steps:

[0014] S5. Close the first isolation valve and the second isolation valve.

[0015] Preferably, the exhaust time of the primary-loop dynamic exhaust regulating valve is 2 hours.

[0016] Preferably, the static exhaust method for the nuclear power primary circuit is suitable for the 1.5 bar to 27 bar platform for overhaul of nuclear power units.

[0017] The present invention also provides a nuclear power primary circuit static exhaust system, which is used for any of the nuclear power primary circuit static exhaust methods described above, wherein the nuclear power primary circuit static exhaust system comprises a top isolation valve connected to the top of the reactor pressure vessel, a connecting pipeline connected between the top isolation valve and the nuclear island exhaust and drain system, a first isolation valve, a second isolation valve, a primary circuit exhaust isolation valve and a primary circuit dynamic exhaust regulating valve sequentially arranged on the connecting pipeline;

[0018] The primary circuit dynamic exhaust regulating valve has a small opening that does not leave the closing limit position.

[0019] Preferably, there are two parallel connecting branches between the top isolation valve and the primary exhaust isolation valve, and each of the connecting branches is provided with the first isolation valve and the second isolation valve.

[0020] Preferably, the nuclear power primary-loop static exhaust system further comprises a primary-loop static exhaust isolation valve arranged in parallel with the primary-loop dynamic exhaust regulating valve.

[0021] Preferably, the nuclear power primary circuit static exhaust system also includes a reactor pressure vessel, a nuclear island exhaust and a drain system.

[0022] The beneficial effects of the present invention are as follows: the non-condensable gas in the primary circuit of nuclear power can be effectively removed to meet the gas content requirement; it is suitable for static exhaust on a higher pressure platform up to 27 bar.g, and the exhaust effect is good; the overhaul period is greatly shortened, and the economic benefits of the power station are improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0024] Figure 1 It is a connection diagram of a static exhaust system of a nuclear power primary circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0026] The static exhaust method of the nuclear power primary circuit of the present invention is used for static exhaust of the primary circuit of the nuclear power unit overhaul ascending higher pressure platform, effectively removing the non-condensable gas in the primary circuit and meeting the gas content requirement. The higher pressure platform includes 1.5 bar.g ~ 27 bar.g platform.

[0027] The static exhaust method for a nuclear power primary circuit of the present invention is implemented by a static exhaust system for a nuclear power primary circuit.

[0028] like Figure 1 As shown, a nuclear power primary static exhaust system according to an embodiment of the present invention comprises a reactor pressure vessel 100, a nuclear island exhaust and drain system (RPE) 200, a top isolation valve 10 connected to the top of the reactor pressure vessel 100, a connecting pipeline 50 connected between the top isolation valve 10 and the nuclear island exhaust and drain system 200, a first isolation valve 11, a second isolation valve 12, a primary exhaust isolation valve 20 and a primary dynamic exhaust regulating valve 30 sequentially arranged on the connecting pipeline 50.

[0029] On the connecting pipeline 50 , the primary exhaust isolation valve 20 and the primary exhaust dynamic regulating valve 30 are located on the side of the second isolation valve 12 away from the first isolation valve 11 .

[0030] The primary circuit dynamic exhaust regulating valve 30 is a regulating valve that can accurately adjust the flow rate, pressure, temperature and other parameters of the fluid according to the process requirements, and can be adjusted within a large flow range to meet the needs of different working conditions. The primary circuit dynamic exhaust regulating valve 30 satisfies the control of the static exhaust rate in a higher pressure platform.

[0031] The primary circuit dynamic exhaust regulating valve 30 has a small opening that does not leave the closing limit. It can also be said that when the main console does not display the opening (the opening limit is not triggered), the primary circuit dynamic exhaust regulating valve 30 can exhaust with a small opening.

[0032] In order to meet the pressure distribution of a higher pressure platform, the passage between the top isolation valve 10 and the primary exhaust isolation valve 20 includes two parallel connecting branches 51 , and each connecting branch 51 is provided with a first isolation valve 11 and a second isolation valve 12 .

[0033] Furthermore, the nuclear power primary static exhaust system may also include a primary static exhaust isolation valve 40 arranged in parallel with the primary dynamic exhaust regulating valve 30. The primary static exhaust isolation valve 40 is a stop valve, which can effectively cut off the flow of fluid, has reliable sealing performance, and is suitable for occasions with high sealing requirements.

[0034] The primary-loop static exhaust isolation valve 40 is suitable for static exhaust of a 1.5 bar platform. Therefore, when the nuclear power primary-loop static exhaust method of the present invention is applied to static exhaust of a 1.5 bar platform, it is achieved by adjusting the primary-loop static exhaust isolation valve 40 .

[0035] refer to Figure 1 A static exhaust method for a nuclear power primary circuit according to an embodiment of the present invention may include the following steps:

[0036] S1. The main control operator can remotely open the first isolation valve 11 and the second isolation valve 12 on the connecting pipeline 50 between the top isolation valve 10 of the reactor pressure vessel 100 and the nuclear island exhaust and drain system 200.

[0037] In some embodiments, there are two parallel connecting branches 51 between the top isolation valve 10 and the primary exhaust isolation valve 20, and each connecting branch 51 is provided with a first isolation valve 11 and a second isolation valve 12. In step S1, the first isolation valve 11 and the second isolation valve 12 on one connecting branch 51 or two connecting branches 51 are opened. In combination with the application on a higher pressure platform, it is preferred to open the first isolation valve 11 and the second isolation valve 12 on the two connecting branches 51.

[0038] S2. After the on-site operator opens the top isolation valve 10 of the reactor pressure vessel 100 and the primary exhaust isolation valve 20 on the connecting pipeline 50, he slowly opens the primary dynamic exhaust regulating valve 30 on the connecting pipeline 50 to exhaust the gas, accompanied by a throttling sound (the throttling sound can be heard on-site).

[0039] The opening of the primary-loop dynamic exhaust regulating valve 30 is controlled at a small opening; at the small opening, the primary-loop dynamic exhaust regulating valve 30 does not leave the closing limit position (the opening limit position is not triggered).

[0040] While the primary circuit dynamic exhaust regulating valve 30 is opened for exhaust, the on-site operator maintains hotline communication with the main control operator so as to make adjustments according to the display of the main console to prevent large fluctuations in the primary circuit pressure.

[0041] S3. When a continuous water flow is discharged from the primary-loop dynamic exhaust regulating valve 30 and there are no bubbles in the water flow, the primary-loop dynamic exhaust regulating valve 30 is closed.

[0042] In this step, whether there is continuous water outflow can be observed through the downstream window of the primary circuit dynamic exhaust regulating valve 30. When there are no bubbles in the water flow, the primary circuit dynamic exhaust regulating valve 30 is slowly closed.

[0043] Preferably, after there is a continuous water flow downstream of the connecting pipeline 50, the primary circuit dynamic exhaust regulating valve 30 is closed after exhausting for a short period of time (such as 1 minute).

[0044] S4. Close the top isolation valve 10 and the primary exhaust isolation valve 20 in sequence.

[0045] S5. After the static exhaust gas is qualified, the first isolation valve 11 and the second isolation valve 12 can be closed by the main control operator.

[0046] The exhaust time of the entire static exhaust can be but not limited to 2 hours, which can be increased or decreased according to actual conditions.

[0047] In the actual application of static exhaust at a 24.5 bar.g platform, the exhaust time is about 2 hours. At the same time, the time for reducing the pressure to a 1.5 bar platform for static exhaust and re-pressurizing to a 24.5 bar pressure platform is saved, which greatly reduces the overhaul period and directly improves the economic benefits of the power station. The above is only an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for static exhaust of a nuclear power primary circuit, characterized in that: The following steps are involved: S1, remotely open the first isolation valve and the second isolation valve on the connecting pipeline between the top isolation valve of the reactor pressure vessel and the nuclear island exhaust and drain system; S2. After opening the top isolation valve of the reactor pressure vessel and the primary exhaust isolation valve on the connecting pipeline on site, slowly open the primary dynamic exhaust regulating valve on the connecting pipeline to exhaust the gas, accompanied by a throttling sound; Wherein, the primary exhaust isolation valve and the primary dynamic exhaust regulating valve are sequentially located on the side of the second isolation valve away from the first isolation valve; the opening of the primary dynamic exhaust regulating valve is a small opening that does not leave the closing limit; S3, after the primary-loop dynamic exhaust regulating valve discharges a continuous water flow and there are no bubbles in the water flow, the primary-loop dynamic exhaust regulating valve is closed.

2. The method for static exhaust of a nuclear power primary circuit according to claim 1, characterized in that: There are two parallel connecting branches between the top isolating valve and the primary exhaust isolating valve, and each of the connecting branches is provided with the first isolating valve and the second isolating valve; In step S1, the first isolation valve and the second isolation valve on one or two of the connecting branches are opened.

3. The method for static exhaust of a nuclear power primary circuit according to claim 1, characterized in that: The following steps are also included: S4. Close the top isolation valve and the primary exhaust isolation valve in sequence.

4. The method for static exhaust of a nuclear power primary circuit according to claim 3, characterized in that: The following steps are also included: S5. Close the first isolation valve and the second isolation valve.

5. The method for static exhaust of a nuclear power primary circuit according to any one of claims 1 to 4, characterized in that: The exhaust time of the primary circuit dynamic exhaust regulating valve is 2h.

6. The method for static exhaust of a nuclear power primary circuit according to any one of claims 1 to 4, characterized in that: The static exhaust method for the nuclear power primary circuit is applicable to the 1.5 bar to 27 bar platform for overhaul of nuclear power units.

7. A static exhaust system for a nuclear power primary circuit, characterized in that: A static exhaust method for a nuclear power primary circuit as claimed in any one of claims 1 to 6, wherein the static exhaust system for a nuclear power primary circuit comprises a top isolation valve connected to the top of a reactor pressure vessel, a connecting pipeline connected between the top isolation valve and a nuclear island exhaust and drain system, a first isolation valve, a second isolation valve, a primary circuit exhaust isolation valve and a primary circuit dynamic exhaust regulating valve sequentially arranged on the connecting pipeline; The primary circuit dynamic exhaust regulating valve has a small opening that does not leave the closing limit position.

8. The nuclear power primary circuit static exhaust system according to claim 7, characterized in that: There are two parallel connecting branches between the top isolating valve and the primary exhaust isolating valve, and each of the connecting branches is provided with the first isolating valve and the second isolating valve.

9. The nuclear power primary circuit static exhaust system according to claim 7 or 8, characterized in that: The nuclear power primary circuit static exhaust system also includes a primary circuit static exhaust isolation valve arranged in parallel with the primary circuit dynamic exhaust regulating valve.

10. The nuclear power primary circuit static exhaust system according to claim 9, characterized in that: The nuclear power primary circuit static exhaust system also includes a reactor pressure vessel, a nuclear island exhaust and a drain system.

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