A boron concentration monitoring system and method under multiple pressure platforms in a nuclear power plant primary circuit

Abstract

The present invention relates to the field of nuclear power, and in particular to a boron concentration monitoring system and method for a nuclear power plant under multiple pressure platforms in a primary circuit. The method comprises the following steps: determining the primary circuit pressure platform; switching the boron concentration monitoring system to an online mode according to changes in the primary circuit pressure platform; when the primary circuit is at a high pressure platform P1, the boron concentration monitoring system switches to online mode one; when the primary circuit is at a medium pressure platform P2, the boron concentration monitoring system switches to online mode two; and when the primary circuit is at a low pressure platform P3, the boron concentration monitoring system switches to online mode three. The present invention realizes automatic adjustment of the boron meter sampling flow rate under multiple pressure platforms in a primary circuit, thereby achieving the purpose of real-time monitoring of the boron concentration in the primary circuit.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power, and in particular to a boron concentration monitoring system and method under multiple pressure platforms in a primary circuit of a nuclear power plant. Background Art

[0002] During reactor startup, power regulation, and shutdown, nuclear power plants control core reactivity by adding or reducing boric acid to the reactor's primary coolant circuit. Because there's a risk of altered core reactivity due to inadvertent boric acid addition or reduction, real-time monitoring of boron concentration in the primary circuit is crucial.

[0003] During startup, power regulation, and shutdown of a pressurized water reactor nuclear power plant, when the primary circuit pressure changes, the online mode of the boron concentration monitoring system needs to be adjusted accordingly to meet the boron meter sampling flow rate. Currently, the boron concentration monitoring system can automatically adjust the boron meter sampling flow rate at the primary circuit's high and medium pressure platforms. However, it lacks an automatic adjustment device for the boron meter sampling flow rate at the primary circuit's low pressure platform, requiring manual adjustment of the boron meter sampling flow rate. Consequently, there is a risk that the boron meter flow rate will fall below the required value due to untimely manual adjustment due to primary circuit pressure changes, resulting in a loss of primary circuit boron concentration monitoring functionality and a significant nuclear safety risk during operation at the primary circuit's low pressure platform. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a boron concentration monitoring system and method under multiple pressure platforms of a primary circuit of a nuclear power plant, realize automatic adjustment of the boron meter sampling flow under multiple pressure platforms of a primary circuit, and achieve the purpose of real-time monitoring of the boron concentration in the primary circuit.

[0005] The present invention provides a boron concentration monitoring system under multiple pressure platforms of a primary circuit of a nuclear power plant, comprising:

[0006] The downflow port of the primary circuit is connected to the first pipeline, on which the first stage cooler, the low-sensitivity pressure reducing valve, the first and second stage coolers, and the first pressure gauge are sequentially arranged;

[0007] A second pipeline is provided between the first stage cooler and the low-sensitivity pressure reducing valve;

[0008] The outlet of the waste heat removal pump is connected to a third pipeline, on which a second primary cooler, a medium-sensitive pressure reducing valve, a second secondary cooler and a second pressure gauge are sequentially arranged;

[0009] A fourth pipeline is provided between the second-stage cooler and the medium-sensitive pressure reducing valve, and a high-sensitive pressure reducing valve and a third pressure gauge are provided on the fourth pipeline; the opening of the high-sensitive pressure reducing valve changes with the pressure measured by the third pressure gauge to achieve automatic adjustment of the sampling flow rate;

[0010] One end of the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are all arranged in the glove box;

[0011] The fifth pipeline and the sixth pipeline are connected in parallel, one end of each of the fifth pipeline and the sixth pipeline is disposed in the glove box, and the other end is connected to the control box through the seventh pipeline; the other end of the control box is connected to the recovery port of the primary circuit;

[0012] The fifth pipeline is provided with a boron meter; the sixth pipeline is provided with a second flow meter; the seventh pipeline is provided with a first flow meter;

[0013] When monitoring boron concentration at different pressure platforms, the connection between different pipelines is realized in the glove box;

[0014] When monitoring boron concentration under the high pressure platform P1, the first pipeline is connected to the fifth pipeline;

[0015] When monitoring boron concentration at the medium pressure platform P2, the third pipeline is connected to the fifth pipeline;

[0016] When the boron concentration is monitored under the low pressure platform P3, the fourth pipeline is connected to the fifth pipeline, and the sixth pipeline is connected to the second pipeline.

[0017] In a specific embodiment of the present invention, the automatic adjustment system of the high-sensitivity pressure reducing valve includes:

[0018] The prediction module is used to compare the measured pressure value with the pressure set value, calculate the pressure difference signal and send it to the amplifier module;

[0019] The amplifier module is used to amplify the pressure difference signal and send the amplified signal to the filter module;

[0020] The filtering module is used to filter the amplified signal and send the filtered signal to the adjustment module;

[0021] The regulating module is used to regulate the filtered signal and convert it into a voltage signal, which is then sent to the output module.

[0022] Output module, used to convert voltage signal into valve opening signal and send it to the actuator;

[0023] Actuator, used to adjust the opening of the high-sensitivity pressure reducing valve.

[0024] In one embodiment of the present invention, 2.3 MPa.g < the pressure of the high pressure platform P1 ≤ 15.4 MPa.g;

[0025] 0.35MPa.g<pressure of medium pressure platform P2≤2.3MPa.g;

[0026] 0MPa.g≤The pressure of the low pressure platform P3≤0.35MPa.g.

[0027] In a specific embodiment of the present invention, the first pipeline is provided with a first manual isolation valve, a first primary cooler, a low-sensitivity pressure reducing valve, a first secondary cooler, a first pressure gauge and a second manual isolation valve in sequence;

[0028] A second pipeline is provided between the first stage cooler and the low-sensitivity pressure reducing valve, and a third manual isolation valve is provided on the second pipeline;

[0029] The third pipeline is sequentially provided with a fourth manual isolation valve, a second primary cooler, a medium-sensitive pressure reducing valve, a second secondary cooler, a second pressure gauge and a fifth manual isolation valve;

[0030] The fourth pipeline is provided with a high-sensitivity pressure reducing valve, a third pressure gauge and a sixth manual isolation valve;

[0031] A seventh manual isolation valve and a boron meter are provided on the five pipelines;

[0032] A second flow meter and a ninth manual isolation valve are provided on the sixth pipeline;

[0033] The seventh pipeline is provided with a first flow meter and an eighth manual isolation valve.

[0034] The present invention provides a method for monitoring boron concentration under multiple pressure platforms in a primary circuit of a nuclear power plant, comprising the following steps:

[0035] Step 1: Determine the primary circuit pressure platform;

[0036] Step 2: According to the change of the primary circuit pressure platform, switch the boron concentration monitoring system to online mode;

[0037] When the primary circuit is at the high pressure platform P1, the boron concentration monitoring system switches to online mode 1;

[0038] When the primary circuit is at the medium pressure platform P2, the boron concentration monitoring system switches to online mode 2;

[0039] When the primary circuit is at the low pressure platform P3, the boron concentration monitoring system switches to online mode three;

[0040] The first online method is specifically as follows: the first pipeline is connected to the fifth pipeline, the driving pressure head is provided by the pressure difference between the primary circuit pressure and the control box to meet the sampling flow rate, and the opening of the low-sensitivity pressure reducing valve changes with the pressure measured by the first pressure gauge to achieve automatic adjustment of the sampling flow rate;

[0041] The second online method is specifically as follows: the third pipeline is connected to the fifth pipeline, the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump and the control box to meet the sampling flow rate, and the opening of the medium-sensitive pressure reducing valve changes with the pressure measured by the second pressure gauge to achieve automatic adjustment of the sampling flow rate;

[0042] The online method three is specifically as follows: the fourth pipeline is connected to the fifth pipeline, and the sixth pipeline is connected to the second pipeline; the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat discharge pump and the primary circuit pressure to meet the sampling flow rate, and the opening of the high-sensitive pressure reducing valve changes with the pressure measured by the third pressure gauge to achieve automatic adjustment of the sampling flow rate.

[0043] In one embodiment of the present invention, 2.3 MPa.g < the pressure of the high pressure platform P1 ≤ 15.4 MPa.g;

[0044] 0.35MPa.g<pressure of medium pressure platform P2≤2.3MPa.g;

[0045] 0MPa.g≤The pressure of the low pressure platform P3≤0.35MPa.g.

[0046] In a specific embodiment of the present invention, the online method is specifically as follows: the boron concentration monitoring system under the multi-pressure platform of the primary circuit of the nuclear power plant leads the primary circuit coolant out from the downflow port of the primary circuit through the first manual isolation valve, and passes through the first stage cooler, the low-sensitivity pressure reducing valve, the first and second stage coolers and the second manual isolation valve in sequence into the glove box, and uses a hose in the glove box to lead the primary circuit coolant to the upstream of the seventh manual isolation valve, and then passes through the boron meter, the first flow meter and the eighth manual isolation valve into the control box, and finally returns to the primary circuit.

[0047] In a specific embodiment of the present invention, the online method 2 is specifically as follows: the boron concentration monitoring system under the multi-pressure platform of the primary circuit of the nuclear power plant leads the primary circuit coolant out from the outlet of the waste heat discharge pump through the fourth manual isolation valve, and passes through the second primary cooler, the medium-sensitive pressure reducing valve, the second secondary cooler and the fifth manual isolation valve in sequence into the glove box, and uses a hose in the glove box to lead the primary circuit coolant to the upstream of the seventh manual isolation valve, and then passes through the boron meter, the first flow meter and the eighth manual isolation valve into the capacity control box, and finally returns to the primary circuit.

[0048] In a specific embodiment of the present invention, the online method three is specifically as follows: the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant leads the primary circuit coolant out from the outlet of the waste heat discharge pump through the fourth manual isolation valve, and passes through the second primary cooler, the high-sensitive pressure reducing valve and the sixth manual isolation valve in sequence into the glove box, and uses a hose to lead the primary circuit coolant to the upstream of the seventh manual isolation valve in the glove box, and then passes through the boron meter, the ninth manual isolation valve and the second flow meter, and is led to the downstream of the third manual isolation valve through a hose in the glove box, and then returns to the upstream of the primary circuit steam generator in the reverse direction through the first primary cooler and the first manual isolation valve.

[0049] In a specific embodiment of the present invention, the primary loop is at the low pressure platform P3. After the reactor unloads fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary loop of the nuclear power plant is shut down. Before the reactor is loaded with fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary loop of the nuclear power plant is put back into operation and monitored using online method three.

[0050] Compared with the prior art, the boron concentration monitoring system and method under multiple pressure platforms of a nuclear power plant's primary circuit of the present invention fully utilize the pressure difference between the primary circuit pressure and the control box, the pressure difference between the outlet pressure of the waste heat removal pump and the control box, and the pressure difference between the outlet pressure of the waste heat removal pump and the primary circuit pressure, respectively, to provide a driving pressure head, thereby ensuring the stability of the boron concentration monitoring flow under multiple pressure platforms of the primary circuit and realizing automatic adjustment of the boron meter sampling flow. In particular, the pressure reducing valve and the pressure gauge cooperate, and the opening of the pressure reducing valve changes with the pressure measured by the pressure gauge to realize automatic adjustment of the boron meter sampling flow. The present invention effectively avoids the implementation of manual adjustment under a low pressure platform of the primary circuit, and also avoids the risk of loss of the primary circuit boron concentration monitoring function. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 A schematic diagram of an online boron concentration monitoring system under multiple pressure platforms in a primary circuit of a nuclear power plant;

[0052] Figure 2 A schematic diagram of an online method 2 of a boron concentration monitoring system under multiple pressure platforms in a primary circuit of a nuclear power plant;

[0053] Figure 3 Schematic diagram of an online boron concentration monitoring system for a nuclear power plant with multiple pressure platforms in a primary circuit;

[0054] Figure 4 This is the schematic diagram of the automatic adjustment system of the high-sensitivity pressure reducing valve of the boron concentration monitoring system under the low pressure platform of the primary circuit;

[0055] Figure 5 A schematic diagram of a method for using a boron concentration monitoring system under multiple pressure platforms in a primary circuit of a nuclear power plant;

[0056] In the figure, 1-first manual isolation valve; 2-first primary cooler; 3-low-sensitivity pressure reducing valve; 4-first secondary cooler; 5-first pressure gauge; 6-second manual isolation valve; 7-third manual isolation valve; 8-fourth manual isolation valve; 9-second primary cooler; 10-medium-sensitive pressure reducing valve; 11-second secondary cooler; 12-second pressure gauge; 13-fifth manual isolation valve; 14-high-sensitivity pressure reducing valve; 15-third pressure gauge; 16-sixth manual isolation valve; 17-seventh manual isolation valve; 18-boron meter; 19-first flow meter; 20-eighth manual isolation valve; 21-capacity control box; 22-ninth manual isolation valve; 23-second flow meter; 24-reactor pressure vessel; 25-steam generator; 26-main pump; 27-waste heat removal pump; 28-glove box. DETAILED DESCRIPTION

[0057] In order to further understand the present invention, embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than for limiting the present invention.

[0058] The embodiment of the present invention discloses a boron concentration monitoring system under multiple pressure platforms of a nuclear power plant primary circuit, such as Figures 1-3 Shown, including:

[0059] The downflow port of the primary circuit is connected to the first pipeline, on which the first primary cooler 2, the low-sensitivity pressure reducing valve 3, the first and second secondary coolers 4, and the first pressure gauge 5 are sequentially arranged;

[0060] Manual isolation valves are respectively provided before the first stage cooler 2 and after the first and second stage coolers 4;

[0061] Specifically,

[0062] The first pipeline is provided with a first manual isolation valve 1, a first primary cooler 2, a low-sensitivity pressure reducing valve 3, a first secondary cooler 4, a first pressure gauge 5 and a second manual isolation valve 6 in sequence;

[0063] A second pipeline is provided between the first primary cooler 2 and the low-sensitivity pressure reducing valve 3, and a third manual isolation valve 7 is provided on the second pipeline;

[0064] The outlet of the waste heat discharge pump is connected to the third pipeline, on which the second primary cooler 9, the medium-sensitive pressure reducing valve 10, the second secondary cooler 11 and the second pressure gauge 12 are sequentially arranged;

[0065] Manual isolation valves are respectively provided before the second primary cooler 9 and after the second secondary cooler 11;

[0066] Specifically,

[0067] The third pipeline is provided with a fourth manual isolation valve 8, a second primary cooler 9, a medium-sensitive pressure reducing valve 10, a second secondary cooler 11, a second pressure gauge 12 and a fifth manual isolation valve 13 in sequence;

[0068] A fourth pipeline is provided between the second primary cooler 9 and the medium-sensitive pressure reducing valve 10, and a high-sensitive pressure reducing valve 14, a third pressure gauge 15 and a sixth manual isolation valve 16 are provided on the fourth pipeline;

[0069] The principle of the automatic adjustment system of the high-sensitivity pressure reducing valve 14 is as follows Figure 4 As shown, the opening of the high-sensitive pressure reducing valve 14 changes with the pressure measured by the third pressure gauge 15, so as to realize automatic adjustment of the sampling flow of the boron meter 18.

[0070] The actual pressure value of the third pressure gauge 15 is sent to the prediction module in the automatic adjustment system of the high-sensitivity pressure reducing valve 14. After the actual pressure value is compared with the pressure setting value in the prediction module, the pressure difference signal △P is calculated and sent to the amplifier module. After amplification, it is sent to the filter module. After filtering, it is sent to the adjustment module, converted into a voltage signal, sent to the output module, converted into a valve opening signal, and sent to the actuator. The actuator adjusts the opening of the high-sensitivity pressure reducing valve 14.

[0071] An amplifier module and a filter module are used in the automatic adjustment system of the high-sensitivity pressure reducing valve 14. The amplifier module can amplify the smaller pressure difference signal under the low-pressure platform of the first circuit, thereby improving the adjustment sensitivity of the high-sensitivity pressure reducing valve 14. The filter module can filter out the false spike signal that is easily generated under the low-pressure platform of the first circuit, thereby improving the adjustment stability of the high-sensitivity pressure reducing valve 14. In this way, the requirements for the sensitive and stable adjustment performance of the high-sensitivity pressure reducing valve 14 under the low-pressure platform are ensured, and the automatic adjustment of the sampling flow of the boron meter 18 under the low-pressure platform can be realized, thereby eliminating the need for manual adjustment of the sampling flow of the boron meter 18 through the sixth manual isolation valve 16.

[0072] One end of the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are all disposed in the glove box 28;

[0073] The fifth pipeline and the sixth pipeline are connected in parallel, one end of the fifth pipeline and the sixth pipeline are both arranged in the glove box 28, and the other end is connected to the control box 21 through the seventh pipeline;

[0074] A seventh manual isolation valve 17 and a boron meter 18 are provided on the fifth pipeline;

[0075] The sixth pipeline is provided with a second flow meter 23 and a ninth manual isolation valve 22;

[0076] The seventh pipeline is provided with a first flow meter 19 and an eighth manual isolation valve 20;

[0077] The other end of the control box 21 is connected to the recovery port of the primary circuit;

[0078] When monitoring boron concentration at different pressure platforms, connections between different pipelines are achieved within the glove box 28;

[0079] When monitoring boron concentration under the high pressure platform P1, the first pipeline is connected to the fifth pipeline;

[0080] When monitoring boron concentration at the medium pressure platform P2, the third pipeline is connected to the fifth pipeline;

[0081] When the boron concentration is monitored under the low pressure platform P3, the fourth pipeline is connected to the fifth pipeline, and the sixth pipeline is connected to the second pipeline.

[0082] The primary circuit consists of a reactor pressure vessel 24 , a steam generator 25 and a main pump 26 .

[0083] An embodiment of the present invention discloses a method for monitoring boron concentration in a nuclear power plant primary circuit under multiple pressure platforms, comprising the following steps:

[0084] According to the changes of the primary circuit pressure platform, switch the online mode of the boron concentration monitoring system under multiple pressure platforms of the primary circuit of the nuclear power plant;

[0085] According to the primary circuit pressure of the nuclear power plant, three pressure platforms are defined from high to low, namely high pressure platform P1, medium pressure platform P2, and low pressure platform P3;

[0086] 2.3MPa.g<The pressure of high pressure platform P1≤15.4MPa.g;

[0087] 0.35MPa.g<pressure of medium pressure platform P2≤2.3MPa.g;

[0088] 0MPa.g≤The pressure of low pressure platform P3≤0.35MPa.g;

[0089] When the primary circuit is at the high pressure platform P1, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant switches to the online mode 1, such as Figure 1 As shown;

[0090] The online method 1 is specifically as follows: the first pipeline is connected to the fifth pipeline in the glove box 28, and the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant draws the primary circuit coolant from the primary circuit downflow port through the first manual isolation valve 1, passes through the first primary cooler 2, the low-sensitivity pressure reducing valve 3, the first and second secondary coolers 4, and the second manual isolation valve 6 in sequence into the glove box 28, and uses a hose to lead the primary circuit coolant to the upstream of the seventh manual isolation valve 17 in the glove box 28, and then passes through the boron meter 18, the first flowmeter 19 and the eighth manual isolation valve 20 into the capacity control box 21, and finally returns to the primary circuit.

[0091] In the online mode, the driving pressure head is provided by the pressure difference between the primary circuit pressure and the control box 21 to meet the sampling flow of the boron concentration monitoring system under the multi-pressure platform of the primary circuit of the nuclear power plant. The opening of the low-sensitive pressure reducing valve 3 changes with the pressure measured by the first pressure gauge 5 to realize automatic adjustment of the sampling flow of the boron meter 18.

[0092] When the primary circuit is at the medium pressure platform P2, the pressure difference between the primary circuit pressure and the control box 21 cannot provide sufficient driving pressure head to meet the sampling flow of the boron concentration monitoring system under the primary circuit multiple pressure platforms of the nuclear power plant. Therefore, the boron concentration monitoring system under the primary circuit multiple pressure platforms of the nuclear power plant switches to the online mode 2, such as Figure 2 As shown;

[0093] The online method 2 is specifically as follows: the third pipeline is connected to the fifth pipeline in the glove box 28, and the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant leads the primary circuit coolant from the outlet of the waste heat discharge pump 27 through the fourth manual isolation valve 8, and passes through the second primary cooler 9, the medium-sensitive pressure reducing valve 10, the second secondary cooler 11 and the fifth manual isolation valve 13 in sequence into the glove box 28. In the glove box 28, the primary circuit coolant is led to the upstream of the seventh manual isolation valve 17 by using a hose, and then passes through the boron meter 18, the first flowmeter 19 and the eighth manual isolation valve 20 into the capacity control box 21, and finally returns to the primary circuit.

[0094] In the second online mode, the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump 27 and the control box 21 to meet the sampling flow of the boron concentration monitoring system under the multi-pressure platform of the primary circuit of the nuclear power plant. The opening of the medium-sensitive pressure reducing valve 10 changes with the pressure measured by the second pressure gauge 12 to realize automatic adjustment of the sampling flow of the boron meter 18.

[0095] When the primary circuit is at the low pressure platform P3, the control box 21 is shut down, and the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant is switched to the online mode 3, such as Figure 3 As shown;

[0096] The online method three is specifically as follows: the fourth pipeline is connected to the fifth pipeline in the glove box 28, and the sixth pipeline is connected to the second pipeline in the glove box 28. The boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant draws the primary circuit coolant from the outlet of the waste heat removal pump 27 through the fourth manual isolation valve 8, passes through the second primary cooler 9, the high-sensitive pressure reducing valve 14 and the sixth manual isolation valve 16 in sequence, enters the glove box 28, and uses a hose to guide the primary circuit coolant to the upstream of the seventh manual isolation valve 17 in the glove box 28. Then, it passes through the boron meter 18, the ninth manual isolation valve 22 and the second flowmeter 23, and is guided to the downstream of the third manual isolation valve 7 in the glove box 28 through a hose. Then, it passes in the opposite direction through the first primary cooler 2 and the first manual isolation valve 1 and returns to the upstream of the steam generator 25 of the primary circuit.

[0097] In online mode three, the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump 27 and the primary circuit pressure to meet the sampling flow of the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant. The opening of the high-sensitive pressure reducing valve 14 changes with the pressure measured by the third pressure gauge 15 to realize automatic adjustment of the sampling flow of the boron meter 18.

[0098] In order to further understand the present invention, the boron concentration monitoring system and method under multiple pressure platforms of a nuclear power plant primary circuit provided by the present invention are described in detail below in conjunction with the embodiments. The protection scope of the present invention is not limited by the following embodiments.

[0099] Example 1

[0100] Taking Qinshan Second Nuclear Power Plant Unit 3 / 4 as an example, the three pressure platforms P1, P2, and P3 of the primary circuit pressure from high to low are defined as follows:

[0101] High pressure platform P1: 2.3MPa.g<pressure≤15.4MPa.g, adopting online method 1;

[0102] Medium pressure platform P2: 0.35MPa.g<pressure≤2.3MPa.g, adopt online method 2;

[0103] Low pressure platform P3: 0MPa.g≤pressure≤0.35MPa.g, adopting online method three.

[0104] 1. High pressure platform P1

[0105] like Figure 1 As shown, when the primary circuit is at the high pressure platform P1, the boron concentration monitoring system under the primary circuit multiple pressure platforms of the nuclear power plant adopts online mode 1, and the driving pressure head is provided by the pressure difference between the primary circuit pressure and the control box 21.

[0106] The first manual isolation valve 1 opens, and the primary coolant is drawn from the upstream of the steam generator 25. Passing through the first primary cooler 2, the temperature drops from 327°C to 60°C. Passing through the low-sensitivity pressure reducing valve 3, the pressure drops from P1 to 0.7 MPa.g. Passing through the first and second secondary coolers 4, the temperature drops from 60°C to below 35°C. The second manual isolation valve 6 opens, and in the glove box 28, the primary coolant is led to the upstream of the seventh manual isolation valve 17 using a hose. The seventh manual isolation valve 17 opens, passes through the boron meter 18 and the first flowmeter 19, and the ninth manual isolation valve 22 closes. The eighth manual isolation valve 20 opens, and the primary coolant enters the control box 21 before returning to the primary circuit. When the primary circuit is at the high pressure platform P1, the automatic adjustment capability of the low-sensitivity pressure reducing valve 3 can meet the requirement that the reading of the first flowmeter 19 is greater than 120 L / h.

[0107] 2. Medium pressure platform P2

[0108] like Figure 2 As shown, when the primary circuit is at the medium pressure platform P2, the boron concentration monitoring system under the primary circuit multiple pressure platforms of the nuclear power plant adopts the online method 2, and the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump 27 and the control box 21.

[0109] The fourth manual isolation valve 8 is opened, and the first-circuit coolant is drawn out from the outlet of the waste heat discharge pump 27, passes through the second first-stage cooler 9, and the temperature drops from 180°C to 60°C. After passing through the medium-sensitive pressure reducing valve 10, the pressure drops from the outlet pressure of the waste heat discharge pump 27 to 0.7Mpa.g. After passing through the second second-stage cooler 11, the temperature drops from 60°C to below 35°C. The fifth manual isolation valve 13 is opened, and a hose is used in the glove box 28 to lead the first-circuit coolant to the upstream of the seventh manual isolation valve 17. The seventh manual isolation valve 17 is opened, passes through the boron meter 18 and the first flow meter 19, and the ninth manual isolation valve 22 is closed. The eighth manual isolation valve 20 is opened, and the first-circuit coolant enters the control box 21 and finally returns to the first circuit. When the first circuit is at the medium pressure platform P2, the automatic adjustment capability of the medium-sensitive pressure reducing valve 10 can meet the requirement that the reading of the first flow meter 19 is greater than 30L / h.

[0110] 3. Low pressure platform P3

[0111] like Figure 3 As shown, when the primary circuit is at the low pressure platform P3, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant adopts the online method three, and the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump 27 and the primary circuit pressure.

[0112] The fourth manual isolation valve 8 opens, and the primary coolant is drawn from the outlet of the waste heat removal pump 27. Passing through the second primary cooler 9, the temperature drops from 70°C to below 35°C. Passing through the high-sensitivity pressure reducing valve 14, the pressure drops from the outlet pressure of the waste heat removal pump 27 to 0.7 MPa.g. The sixth manual isolation valve 16 opens, and the primary coolant is directed via a hose in the glove box 28 upstream of the seventh manual isolation valve 17. The seventh manual isolation valve 17 opens, and the primary coolant passes through a boron meter 18. The eighth manual isolation valve 20 is closed, and the ninth manual isolation valve 22 is opened. The flow rate is monitored by the second flow meter 23. Within the glove box 28, the primary coolant is directed via a hose downstream of the third manual isolation valve 7. The third manual isolation valve 7 opens, and the primary coolant reverses direction through the first primary cooler 2. The first manual isolation valve 1 opens, and the primary coolant returns upstream of the steam generator 25. When the primary coolant reaches the low pressure level P3, the automatic adjustment capability of the high-sensitivity pressure reducing valve 14 meets the requirement that the second flow meter 23 reading be greater than 30 L / h.

[0113] 4. Description of the online switching process of the boron concentration monitoring system under multiple pressure platforms in the primary circuit of the nuclear power plant

[0114] When the primary circuit pressure platform changes between P1, P2, and P3, the online switching process corresponding to the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant is as follows: Figure 5 shown.

[0115] It should be noted that when the primary circuit is at the low pressure platform P3, after the reactor unloads fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant is shut down. Before the reactor is loaded with fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant is put back into operation, and the online method adopts method three.

[0116] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0117] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A boron concentration monitoring system under multiple pressure platforms in a nuclear power plant primary circuit, characterized in that: include: The downflow port of the primary circuit is connected to the first pipeline, on which the first stage cooler, the low-sensitivity pressure reducing valve, the first and second stage coolers, and the first pressure gauge are sequentially arranged; A second pipeline is provided between the first stage cooler and the low-sensitivity pressure reducing valve; The outlet of the waste heat removal pump is connected to a third pipeline, on which a second primary cooler, a medium-sensitive pressure reducing valve, a second secondary cooler and a second pressure gauge are sequentially arranged; A fourth pipeline is provided between the second-stage cooler and the medium-sensitive pressure reducing valve, and a high-sensitive pressure reducing valve and a third pressure gauge are provided on the fourth pipeline; the opening of the high-sensitive pressure reducing valve changes with the pressure measured by the third pressure gauge to achieve automatic adjustment of the sampling flow rate; One end of the first pipeline, the second pipeline, the third pipeline and the fourth pipeline are all arranged in the glove box; The fifth pipeline and the sixth pipeline are connected in parallel, one end of each of the fifth pipeline and the sixth pipeline is disposed in the glove box, and the other end is connected to the control box through the seventh pipeline; the other end of the control box is connected to the recovery port of the primary circuit; The fifth pipeline is provided with a boron meter; the sixth pipeline is provided with a second flow meter; the seventh pipeline is provided with a first flow meter; When monitoring boron concentration at different pressure platforms, the connection between different pipelines is realized in the glove box; When monitoring boron concentration under the high pressure platform P1, the first pipeline is connected to the fifth pipeline; When monitoring boron concentration at the medium pressure platform P2, the third pipeline is connected to the fifth pipeline; When monitoring boron concentration at the low pressure platform P3, the fourth pipeline is connected to the fifth pipeline, and the sixth pipeline is connected to the second pipeline; The three pressure platforms P1, P2, and P3 of the primary circuit pressure from high to low are defined as follows: High pressure platform P1: 2.3MPa.g<pressure≤15.4MPa.g; Medium pressure platform P2: 0.35MPa.g<pressure≤2.3MPa.g; Low pressure platform P3: 0MPa.g≤pressure≤0.35MPa.g.

2. The boron concentration monitoring system under multiple pressure platforms of a nuclear power plant primary circuit according to claim 1, characterized in that: The automatic adjustment system of the high-sensitivity pressure reducing valve includes: The prediction module is used to compare the measured pressure value with the pressure set value, calculate the pressure difference signal and send it to the amplifier module; The amplifier module is used to amplify the pressure difference signal and send the amplified signal to the filter module; The filtering module is used to filter the amplified signal and send the filtered signal to the adjustment module; The regulating module is used to regulate the filtered signal and convert it into a voltage signal, which is then sent to the output module. Output module, used to convert voltage signal into valve opening signal and send it to the actuator; Actuator, used to adjust the opening of the high-sensitivity pressure reducing valve.

3. The boron concentration monitoring system under multiple pressure platforms of a nuclear power plant primary circuit according to claim 1, characterized in that: The first pipeline is provided with a first manual isolation valve, a first primary cooler, a low-sensitivity pressure reducing valve, a first secondary cooler, a first pressure gauge and a second manual isolation valve in sequence; A second pipeline is provided between the first stage cooler and the low-sensitivity pressure reducing valve, and a third manual isolation valve is provided on the second pipeline; The third pipeline is sequentially provided with a fourth manual isolation valve, a second primary cooler, a medium-sensitive pressure reducing valve, a second secondary cooler, a second pressure gauge and a fifth manual isolation valve; The fourth pipeline is provided with a high-sensitivity pressure reducing valve, a third pressure gauge and a sixth manual isolation valve; A seventh manual isolation valve and a boron meter are provided on the five pipelines; A second flow meter and a ninth manual isolation valve are provided on the sixth pipeline; The seventh pipeline is provided with a first flow meter and an eighth manual isolation valve.

4. A monitoring method using the boron concentration monitoring system under multiple pressure platforms of a primary circuit of a nuclear power plant according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Determine the primary circuit pressure platform; Step 2: According to the change of the primary circuit pressure platform, switch the boron concentration monitoring system to online mode; When the primary circuit is at the high pressure platform P1, the boron concentration monitoring system switches to online mode 1; When the primary circuit is at the medium pressure platform P2, the boron concentration monitoring system switches to online mode 2; When the primary circuit is at the low pressure platform P3, the boron concentration monitoring system switches to online mode three; The first online method is specifically as follows: the first pipeline is connected to the fifth pipeline, the driving pressure head is provided by the pressure difference between the primary circuit pressure and the control box to meet the sampling flow rate, and the opening of the low-sensitivity pressure reducing valve changes with the pressure measured by the first pressure gauge to achieve automatic adjustment of the sampling flow rate; The second online method is specifically as follows: the third pipeline is connected to the fifth pipeline, the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat removal pump and the control box to meet the sampling flow rate, and the opening of the medium-sensitive pressure reducing valve changes with the pressure measured by the second pressure gauge to achieve automatic adjustment of the sampling flow rate; The online method three is specifically as follows: the fourth pipeline is connected to the fifth pipeline, and the sixth pipeline is connected to the second pipeline; the driving pressure head is provided by the pressure difference between the outlet pressure of the waste heat discharge pump and the primary circuit pressure to meet the sampling flow rate, and the opening of the high-sensitive pressure reducing valve changes with the pressure measured by the third pressure gauge to achieve automatic adjustment of the sampling flow rate.

5. The method for monitoring boron concentration in a nuclear power plant primary circuit under multiple pressure platforms according to claim 4, characterized in that: The online method 1 is specifically as follows: the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant leads the primary circuit coolant from the primary circuit downflow port through the first manual isolation valve, passes through the first stage cooler, the low-sensitivity pressure reducing valve, the first and second stage coolers and the second manual isolation valve in sequence into the glove box, and uses a hose to lead the primary circuit coolant to the upstream of the seventh manual isolation valve in the glove box, then passes through the boron meter, the first flow meter and the eighth manual isolation valve into the capacity control box, and finally returns to the primary circuit.

6. The method for monitoring boron concentration in a nuclear power plant primary circuit under multiple pressure platforms according to claim 4, characterized in that: The second online method is specifically as follows: the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant leads the primary circuit coolant from the outlet of the waste heat discharge pump through the fourth manual isolation valve, passes through the second first-stage cooler, the medium-sensitive pressure reducing valve, the second second-stage cooler and the fifth manual isolation valve in sequence into the glove box, and uses a hose in the glove box to lead the primary circuit coolant to the upstream of the seventh manual isolation valve, and then passes through the boron meter, the first flow meter and the eighth manual isolation valve into the capacity control box, and finally returns to the primary circuit.

7. The method for monitoring boron concentration in a nuclear power plant primary circuit under multiple pressure platforms according to claim 4, characterized in that: The online method three is specifically as follows: the boron concentration monitoring system under the primary circuit multi-pressure platform of the nuclear power plant leads the primary circuit coolant from the outlet of the waste heat discharge pump through the fourth manual isolation valve, passes through the second primary cooler, the high-sensitive pressure reducing valve and the sixth manual isolation valve in sequence into the glove box, and uses a hose to lead the primary circuit coolant to the upstream of the seventh manual isolation valve in the glove box, then passes through the boron meter, the ninth manual isolation valve and the second flow meter, and is led to the downstream of the third manual isolation valve in the glove box through a hose, and then returns to the upstream of the primary circuit steam generator in the reverse direction through the first primary cooler and the first manual isolation valve.

8. The method for monitoring boron concentration in a nuclear power plant primary circuit under multiple pressure platforms according to claim 4, characterized in that: The primary circuit is at the low pressure platform P3. After the reactor is unloaded with fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant is shut down. Before the reactor is loaded with fuel, the boron concentration monitoring system under the multiple pressure platforms of the primary circuit of the nuclear power plant is put back into operation and monitored using the online method three.

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