Online analysis system and analysis method for boric acid in primary loop coolant

Abstract

The invention relates to the technical field of boric acid concentration detection, in particular to an online analysis system and method for boric acid in a primary loop coolant, and the system comprises a sample injection distribution device, a three-way electromagnetic valve B, a quantitative tube, an analysis cup, a peristaltic pump, a mannitol reagent barrel, a burette module and a sodium hydroxide reagent barrel, the three-way electromagnetic valve B is respectively connected with the sample injection distribution device, the quantitative tube and the analysis cup through pipelines, a cup opening of the analysis cup is sequentially connected with the peristaltic pump and the mannitol reagent barrel through pipelines, the cup opening of the analysis cup is sequentially connected with the burette module and the sodium hydroxide reagent barrel through pipelines, and the burette module is used for extracting a sodium hydroxide reagent and adding the sodium hydroxide reagent into the analysis cup for titration. According to the method, boric acid reacts with a mannitol reagent, the concentration of boric acid is measured through a titration method, practice verifies that the detection precision is higher, the stability is better, and the interference of the external environment and temperature on boric acid concentration detection can be effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of boric acid concentration detection, and particularly to an on-line analysis system and method for boric acid in primary coolant. Background Art

[0002] Adjusting the concentration of boric acid solution in the primary loop can precisely control the reactivity of the nuclear reactor, compensate for the decrease in reactivity caused by nuclear fuel consumption, and ensure the safe and stable operation of the nuclear power plant. Multiple monitoring points in the primary loop system of the nuclear power plant need to measure the boric acid concentration in real time.

[0003] In the prior art, currently on-line boric acid concentration measurement mainly uses the neutron counting method. When the neutron fluence rate is constant, the boric acid concentration is calculated by using the corresponding relationship between the counting rate of the neutron detector and the concentration of boron ( 10 B). This method has large measurement errors and is easily affected by the external environment. For example, when the temperature of the boric acid solution rises or falls, the presence of voids in the pipeline or bubbles in the fluid will cause deviations in the measurement data. Summary of the Invention

[0004] The present invention provides an on-line analysis system and method for boric acid in primary coolant to solve the problem of measurement errors in the existing on-line boric acid concentration measurement method.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention proposes an on-line analysis system for boric acid in primary coolant, which includes: a sampling and distribution device, a three-way solenoid valve B, a metering tube, an analysis cup, a peristaltic pump, a mannitol reagent barrel, a burette module, and a sodium hydroxide reagent barrel. The three-way solenoid valve B is connected to the sampling and distribution device, the metering tube, and the analysis cup through pipelines respectively. The mouth of the analysis cup is connected to the peristaltic pump and the mannitol reagent barrel through pipelines in sequence. The mouth of the analysis cup is connected to the burette module and the sodium hydroxide reagent barrel through pipelines in sequence. The burette module is used to extract sodium hydroxide reagent and add it to the analysis cup for titration.

[0007] In some embodiments, the metering tube is made of quartz glass and has a structure of a constricted thin tube. The primary coolant sample water enters from the bottom and exits from the top of the metering tube. The quantitative volume of the constricted thin tube from the bottom to the top is 20 mL. The top of the constricted thin tube is connected to a glass bulb, and there is a sample discharge hole at the bottom of the bulb; the analysis cup has a flat-bottomed bowl-shaped structure and is made of quartz material; a container holder is provided at the bottom end of the analysis cup, a magnetic bead stirrer is provided at the bottom end inside the analysis cup, and an electric metal turntable is provided inside the container holder. The container holder drives the magnetic bead stirrer through the electric metal turntable, and the magnetic bead stirrer is used to clean and stir the analysis cup.

[0008] In some embodiments, a pH composite electrode is suspended above the analysis cup, and the pH composite electrode measures the pH value of the solution in the analysis cup.

[0009] In some embodiments, the lower part of the analysis cup is connected to a three-way solenoid valve C through a pipeline. The other two ends of the three-way solenoid valve C are respectively connected to a demineralized water inlet pipe and a demineralized water outlet pipe. A three-way solenoid valve A is provided on the pipeline between the three-way solenoid valve B and the sample injection distribution device. The three-way solenoid valve A is also connected to a drain pipe, and the drain pipe is used to drain the excess primary coolant in the sample injection distribution device.

[0010] The present invention provides an on-line analysis method for boric acid in primary coolant, and the method includes:

[0011] Step 1: Inject the primary coolant sample water into a metering tube for quantification;

[0012] Step 2: Use demineralized water to rinse the analysis cup and inject the primary coolant sample water into the analysis cup;

[0013] Step 3: Inject mannitol reagent into the analysis cup to acidify the primary coolant sample water;

[0014] Step 3.1: Start the peristaltic pump and inject the mannitol reagent in the mannitol reagent barrel into the analysis cup;

[0015] Step 3.2: Start the magnetic bead stirrer to stir, so that boric acid in the primary coolant sample water fully reacts with mannitol to generate complex acid;

[0016] Step 4: Titrate the solution in the analysis cup and calculate the boric acid concentration of the primary coolant sample water;

[0017] Step 4.1: The burette module extracts the sodium hydroxide solution in the sodium hydroxide reagent barrel and slowly injects the sodium hydroxide solution into the analysis cup;

[0018] Step 4.2: The pH composite electrode measures the pH value of the solution in the analysis cup. When the indication value of the pH composite electrode 7 reaches 8.31pH, the burette module stops injecting the sodium hydroxide solution;

[0019] Step 4.3: According to the consumption of the sodium hydroxide solution, calculate the concentration of the boric acid solution in the primary loop system. The specific calculation formula is as Formula 1:

[0020]

[0021] Wherein, is the sample boric acid concentration; V NaOH is the volume of the consumed NaOH solution; C NaOH is the NaOH concentration; is the molecular weight of boric acid; is the sample weight;

[0022] Step Five: After the measurement of boric acid concentration is completed, drain the solution in the analysis cup;

[0023] Step Six: Re-calibrate the pH combination electrode.

[0024] In some embodiments, Step One includes:

[0025] Step 1.1: The three-way solenoid valve A connects the pipeline between the three-way solenoid valve B and the sample injection distribution device, and closes the pipeline connected to the drain pipe; the three-way solenoid valve B connects the pipeline between the three-way solenoid valve A and the metering tube, and closes the pipeline connected to the analysis cup;

[0026] Step 1.2: The primary coolant sample water flows into the sample injection distribution device, and successively flows through the three-way solenoid valve A and the three-way solenoid valve B, and enters the metering tube. The primary coolant sample water exceeding the volume of the metering tube flows out from the upper part of the metering tube;

[0027] Step 1.3: When the metering tube is filled, the three-way solenoid valve B closes the pipeline connected to the three-way solenoid valve A, and the three-way solenoid valve A connects to the drain pipe, and the drain pipe discharges the primary coolant sample water flowing in from the sample injection distribution device.

[0028] In some embodiments, Step Two includes:

[0029] Step 2.1: The three-way solenoid valve C connects the demineralized water inlet pipe and the analysis cup, and the demineralized water enters the analysis cup through the brine inlet pipe. After 10 seconds, the three-way solenoid valve C closes the connection with the demineralized water inlet pipe;

[0030] Step 2.2: The magnetic bead stirrer stirs the demineralized water for 20 seconds;

[0031] Step 2.3: The three-way solenoid valve C connects the demineralized water outlet pipe and the analysis cup, and discharges the demineralized water from the analysis cup;

[0032] Step 2.4: Repeat Step 2.1 to Step 2.3 again;

[0033] Step 2.5: The three-way solenoid valve C closes the pipeline connected to the analysis cup, and the three-way solenoid valve B connects the pipeline between the metering tube and the analysis cup, and the primary coolant sample water in the metering tube enters the analysis cup.

[0034] In some embodiments, the stirring duration of the magnetic bead stirrer in Step 3.2 is 30 seconds.

[0035] In some embodiments, Step Five includes:

[0036] Step 5.1: 5 seconds after the measurement of boric acid concentration is completed, the three-way solenoid valve C connects the demineralized water outlet pipe and the analysis cup, and discharges the solution in the analysis cup;

[0037] Step 5.2: The three-way solenoid valve C closes the connection with the demineralized water outlet pipe, and the three-way solenoid valve C connects the demineralized water inlet pipe with the analysis cup, and injects demineralized water into the analysis cup; after 10 seconds, ensure that the pH combination electrode 7 is immersed in the demineralized water, and close the connection between the three-way solenoid valve C and the brine inlet pipe.

[0038] In some embodiments, step six includes:

[0039] Step 6.1: Configure standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18.

[0040] Step 6.2: Take out the pH combination electrode from the analysis cup, set the pH combination electrode to the three-point calibration mode, rinse the pH combination electrode with demineralized water and wipe it clean with filter paper.

[0041] Step 6.3: Calibrate the pH combination electrode by placing it into the standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18 respectively.

[0042] Step 6.4: Retest the pH combination electrode by placing it into the standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18 respectively, and check whether the measured pH value error of the pH combination electrode is within the range of ±0.05. If the pH value error exceeds ±0.05, repeat steps 6.1 to 6.4.

[0043] Step 6.5: Reinstall the pH combination electrode into the analysis cup.

[0044] Implementing the present invention has the following beneficial effects:

[0045] 1. The present invention provides an on-line analysis system and analysis method for boric acid in primary coolant. By reacting boric acid with mannitol reagent and measuring the boric acid concentration by titration method, through practical verification, the detection accuracy is higher and the stability is better, and it can effectively solve the interference of external environment and temperature on the detection of boric acid concentration.

[0046] 2. The present invention provides an on-line analysis system and analysis method for boric acid in primary coolant. In the present invention, by optimizing and improving the structure of the metering tube, the quantification of boric acid solution is more accurate, and at the same time, the excess sample water in the metering tube is automatically discharged, ensuring the accuracy of subsequent detection results.

[0047] 3. The present invention provides an on-line analysis system and analysis method for boric acid in primary coolant. In the present invention, the analysis cup is made of quartz material with good light transmittance and corrosion resistance, and has a flat-bottomed bowl-shaped structure, which can resist the acid-base corrosion of the solution, facilitate the timely cleaning of the flocs generated by mannitol and observe the sample analysis situation.

[0048] 4. The present invention provides an on-line analysis system and method for boric acid in primary coolant. In the present invention, through the combined action of multiple sampling three-way solenoid valves, reagent barrels, peristaltic pumps and motor motors, automatic sampling, dosing, stirring, titration, sample output and cleaning of boric acid solution can be realized, and the operation is more convenient. Description of the Drawings

[0049] Figure 1 Schematic diagram of an on-line analysis system for boric acid in primary coolant proposed in an embodiment of the present invention; Description of the Drawings:

[0051] 1. Sampling distribution device; 2. Three-way solenoid valve; 3. Quantitative tube; 4. Analysis cup; 5. Container holder; 6. Magnetic bead stirrer; 7. pH composite electrode; 8. Peristaltic pump; 9. Mannitol reagent barrel; 10. Burette module; 11. Sodium hydroxide reagent barrel; 21. Three-way solenoid valve A; 22. Three-way solenoid valve B; 23. Three-way solenoid valve C. Detailed Embodiments

[0052] The technical solutions of the present invention will be clearly and completely described below in conjunction with the drawings and specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0053] As Figure 1As shown in the figure, the present invention proposes an on-line analysis system for boric acid in primary coolant, which system includes: a sampling and distribution device 1, a three-way solenoid valve A 21, a three-way solenoid valve B 22, a three-way solenoid valve C 23, a metering tube 3, an analysis cup 4, a container holder 5, a magnetic bead stirrer 6, a pH combination electrode 7, a peristaltic pump 8, a mannitol reagent barrel 9, a burette module 10, and a sodium hydroxide reagent barrel 11. The sampling and distribution device 1 is connected to the primary coolant system, and the primary coolant sample water flows into this system through the sampling and distribution device 1. The sampling and distribution device 1 is sequentially connected to the three-way solenoid valve A 21, the three-way solenoid valve B 22, and the metering tube 3 through pipelines. In addition to being connected to the three-way solenoid valve B 22 and the sampling and distribution device 1, the three-way solenoid valve A 21 is also connected to a drain pipe, which is used to discharge the excess primary coolant in the sampling and distribution device 1; in addition to being connected to the three-way solenoid valve A 21 and the metering tube 3, the three-way solenoid valve B 22 is also connected to the analysis cup 4 through a pipeline. The analysis cup 4 adopts a flat-bottomed bowl-shaped structure and is made of quartz material with good light transmittance and corrosion resistance, which is convenient for timely cleaning of the flocs generated by mannitol and observing the sample analysis situation. The metering tube 3 is made of quartz glass with a smooth and transparent wall surface, and the upper part has a structure of a reduced-diameter thin tube. The sample water enters from the bottom and exits from the top. The quantitative volume at the top of the reduced-diameter thin tube is 20 mL, ensuring sufficient and standard quantification. The top of the reduced-diameter thin tube is connected to a glass bulb, and a sample discharge hole is provided at the bottom of the bulb. The reduced-diameter thin tube passes through the bulb, and the top of the reduced-diameter thin tube stands at the center of the bulb. When the metering tube 3 is quantifying, the excess sample water flows along the wall surface of the bulb to the bottom and is discharged.

[0054] The analysis cup 4 is fixed on the container holder 5. The container holder 5 is internally provided with an electric metal turntable, which can drive the magnetic bead stirrer 6 to rotate rapidly. The magnetic bead stirrer 6 is used to clean and stir the analysis cup 4. The pH combination electrode 7 is suspended above the analysis cup 4, and the pH combination electrode 7 measures the pH value of the solution in the analysis cup 4. The lower part of the analysis cup 4 is connected to the three-way solenoid valve C 23 through a pipeline, and the other two ends of the three-way solenoid valve C 23 are respectively connected to a demineralized water inlet pipe and a demineralized water outlet pipe. The cup mouth of the analysis cup 4 is sequentially connected to the peristaltic pump 8 and the mannitol reagent barrel 9 through pipelines. The peristaltic pump 8 is used to extract mannitol reagent and inject it into the analysis cup 4. At the same time, the cup mouth of the analysis cup 4 is sequentially connected to the burette module 10 and the sodium hydroxide reagent barrel 11 through pipelines. The burette module 10 extracts sodium hydroxide reagent and adds it to the analysis cup 4 for titration. The concentration of the sodium hydroxide reagent is 0.01 mol / L, and sodium hydroxide solutions with other concentrations can also be configured according to needs.

[0055] The present invention proposes an on-line analysis method for boric acid in primary coolant, which method includes:

[0056] Step 1: Inject the primary coolant sample water into the metering tube 3 for quantification;

[0057] Step 1.1: The three-way solenoid valve A21 connects the pipeline between the three-way solenoid valve B22 and the sample injection distribution device 1, and closes the pipeline connected to the drain pipe; the three-way solenoid valve B22 connects the pipeline between the three-way solenoid valve A21 and the metering tube 3, and closes the pipeline connected to the analysis cup 4.

[0058] Step 1.2: The primary coolant sample water flows into the sample injection distribution device 1, successively passes through the three-way solenoid valve A21 and the three-way solenoid valve B22, enters the metering tube 3, and the primary coolant sample water exceeding the volume of the metering tube 3 flows out from the side of the upper bulb of the metering tube 3.

[0059] Step 1.3: When the metering tube 3 is filled, the three-way solenoid valve B22 closes the pipeline connected to the three-way solenoid valve A21, and the three-way solenoid valve A21 connects to the drain pipe to discharge the primary coolant sample water flowing in from the sample injection distribution device 1.

[0060] Step Two: Rinse the analysis cup 4 with demineralized water and inject the primary coolant sample water into the analysis cup 4.

[0061] Step 2.1: The three-way solenoid valve C23 connects the demineralized water inlet pipe and the analysis cup 4, and the demineralized water enters the analysis cup 4 through the brine inlet pipe. After 10 seconds, the three-way solenoid valve C23 closes the connection with the demineralized water inlet pipe.

[0062] Step 2.2: The electric metal turntable in the container holder 5 drives the magnetic bead stirrer 6 to stir the demineralized water for 20 seconds.

[0063] Step 2.3: The three-way solenoid valve C23 connects the demineralized water outlet pipe and the analysis cup 4 to discharge the demineralized water from the analysis cup 4.

[0064] Step 2.4: Repeat Step 2.1 to Step 2.3 again to ensure that the residual boric acid solution in the analysis cup 4 is rinsed clean.

[0065] Step 2.5: The three-way solenoid valve C23 closes the pipeline connected to the analysis cup 4, and the three-way solenoid valve B22 connects the pipeline between the metering tube 3 and the analysis cup 4, and the primary coolant sample water in the metering tube 3 enters the analysis cup 4.

[0066] Step Three: Inject mannitol reagent into the analysis cup 4 to make the boric acid in the primary coolant sample water fully react with mannitol to form complex acid.

[0067] Step 3.1: Start the peristaltic pump 8 to quantitatively inject the mannitol reagent in the mannitol reagent barrel 9 into the analysis cup 4, where the concentration of the mannitol reagent is 100 g / L, and the quantitative injection is specifically: each time 18 - 22 ml of mannitol reagent is injected into the analysis cup 4.

[0068] Step 3.2: The built-in electric metal turntable of the container holder 5 drives the magnetic bead stirrer 6 to stir for 30 seconds, so that boric acid and mannitol in the primary coolant sample water fully react to form complex acid.

[0069] Step Four: Titrate the solution in the analysis cup 4 and calculate the boric acid concentration of the primary coolant sample water;

[0070] Step 4.1: The burette module 10 extracts 50 ml of 0.01 mol / L standard sodium hydroxide solution from the sodium hydroxide reagent barrel 11 and slowly pushes the 0.01 mol / L standard sodium hydroxide solution into the analysis cup 4;

[0071] Step 4.2: The pH composite electrode 7 measures the pH value of the solution in the analysis cup 4. When the indication value of the pH composite electrode 7 reaches 8.31 pH, the burette module 10 stops injecting the sodium hydroxide solution;

[0072] Step 4.3: Calculate the consumption of the standard sodium hydroxide solution according to the stroke progress of the burette module 10, and then calculate the concentration of the boric acid solution in the primary loop system. The specific calculation formula is as Formula 1:

[0073]

[0074] Where, is the boric acid concentration of the sample, in mg / L; V NaOH is the volume of the consumed NaOH solution in mL; is the concentration of NaOH, in mol / L; is the molecular weight of boric acid, specifically 61.83 g / mol; is the weight of the sample, in g.

[0075] Step Five: After the boric acid concentration measurement is completed, drain the solution in the analysis cup 4;

[0076] Step 5.1: 5 seconds after the boric acid concentration measurement is completed, the three-way solenoid valve C23 connects the demineralized water outlet pipe and the analysis cup 4 to drain the solution in the analysis cup 4;

[0077] Step 5.2: The three-way solenoid valve C23 closes the connection with the demineralized water outlet pipe, and the three-way solenoid valve C23 connects the demineralized water inlet pipe and the analysis cup 4 to inject demineralized water into the analysis cup 4; After 10 seconds, ensure that the pH composite electrode 7 is immersed in the demineralized water, and close the connection between the three-way solenoid valve C23 and the brine inlet pipe.

[0078] Step Six: Re-calibrate the pH composite electrode 7.

[0079] Step 6.1: Configure standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18;

[0080] Step 6.2: Take out the pH composite electrode 7 from the analysis cup 4, set it to the three-point calibration mode, rinse the pH composite electrode 7 with demineralized water and wipe it clean with filter paper;

[0081] Step 6.3: Place the pH composite electrode 7 in the pH standard solution with a pH value of 4.00, and complete the calibration of this point through the operation menu. Take out the pH composite electrode 7, rinse it with demineralized water and wipe it clean with filter paper. Place the pH composite electrode 7 in the pH standard solution with a pH value of 6.86, complete the calibration of this point through the operation menu, then rinse it with demineralized water and wipe it clean with filter paper. Place the pH composite electrode 7 in the pH standard solution with a pH value of 9.18, and complete the calibration of this point through the operation menu again;

[0082] Step 6.4: Put the pH composite electrode 7 into the standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18 respectively for retesting, and check whether the measured pH value error of the pH composite electrode 7 is within the range of ±0.05. If the pH value error exceeds ±0.05, repeat Steps 6.1 to 6.4;

[0083] Step 6.5: Reinstall the pH composite electrode 7 into the analysis cup 4.

[0084] The above embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. An on-line analysis system for boric acid in primary coolant, characterized in that, The system includes: a sample injection and distribution device (1), a three-way solenoid valve B (22), a metering tube (3), an analysis cup (4), a peristaltic pump (8), a mannitol reagent barrel (9), a burette module (10), and a sodium hydroxide reagent barrel (11). The three-way solenoid valve B (22) is connected to the sample injection and distribution device (1), the metering tube (3), and the analysis cup (4) respectively through pipelines. The mouth of the analysis cup (4) is connected to the peristaltic pump (8) and the mannitol reagent barrel (9) in sequence through a pipeline. The mouth of the analysis cup (4) is connected to the burette module (10) and the sodium hydroxide reagent barrel (11) in sequence through a pipeline. The burette module (10) is used to extract sodium hydroxide reagent and add it to the analysis cup (4) for titration.

2. The online analysis system for boric acid in the primary coolant according to claim 1, characterized in that The metering tube (3) is made of quartz glass and has a structure of a reduced-orifice thin tube. The primary coolant sample water enters from the bottom and exits from the top of the metering tube (3). The quantitative volume of the reduced-orifice thin tube from the bottom to the top is 20 mL. The top of the reduced orifice of the thin tube is connected to a glass bulb, and a sample discharge hole is provided at the bottom of the bulb. The analysis cup (4) has a flat-bottomed bowl-shaped structure and is made of quartz material. A container holder (5) is provided at the bottom end of the analysis cup (4), and a magnetic bead stirrer (6) is provided at the inner bottom end of the analysis cup (4). An electric metal turntable is provided inside the container holder (5), and the container holder (5) drives the magnetic bead stirrer (6) through the electric metal turntable. The magnetic bead stirrer (6) is used to clean and stir the analysis cup (4).

3. An on-line boric acid analysis system for primary coolant according to claim 2, characterized in that, The pH combination electrode (7) is suspended above the analysis cup (4), and the pH combination electrode (7) measures and analyzes the pH value of the solution in the analysis cup (4).

4. An on-line boric acid analysis system for primary coolant according to claim 3, characterized in that, The lower part of the analysis cup (4) is connected to a three-way solenoid valve C (23) through a pipeline. The other two ends of the three-way solenoid valve C (23) are respectively connected to a demineralized water inlet pipe and a demineralized water outlet pipe. A three-way solenoid valve A (21) is provided on the pipeline between the three-way solenoid valve B (22) and the sample injection and distribution device (1). The three-way solenoid valve A (21) is connected to a drain pipe, and the drain pipe is used to drain the excess primary coolant in the sample injection and distribution device (1).

5. A method for on-line analysis of boric acid in primary coolant according to any one of claims 1-4, characterized in that, The method includes: Step 1: Inject the primary coolant sample water into the metering tube (3) for quantification. Step 2: Use demineralized water to rinse the analysis cup (4) and inject the primary coolant sample water into the analysis cup (4). Step 3: Inject mannitol reagent into the analysis cup (4) so that boric acid in the primary coolant sample water reacts fully with mannitol to form a complex acid. Step 3.1: Start the peristaltic pump (8) to inject the mannitol reagent in the mannitol reagent barrel (9) into the analysis cup (4). Step 3.2: Start the magnetic bead stirrer (6) to stir so that boric acid in the primary coolant sample water reacts fully with mannitol to form a complex acid. Step 4: Titrate the solution in the analysis cup (4) and calculate the boric acid concentration of the primary coolant sample water. Step 4.1: The burette module (10) extracts the sodium hydroxide solution from the sodium hydroxide reagent barrel (11) and slowly injects the sodium hydroxide solution into the analysis cup (4). Step 4.2: The pH combination electrode (7) measures the pH value of the solution in the analysis cup (4). When the indication value of the pH combination electrode (7) reaches 8.31 pH, the burette module (10) stops injecting the sodium hydroxide solution. Step 4.3: Calculate the concentration of the boric acid solution in the primary loop system according to the consumption of the sodium hydroxide solution. The specific calculation formula is as shown in Formula 1: Among them, is the boric acid concentration of the sample; V NaOH is the volume of the consumed NaOH solution; C NaOH is the NaOH concentration; is the molecular weight of boric acid; is the sample weight; Step Five: After the measurement of the boric acid concentration is completed, drain the solution in the analysis cup (4). Step Six: Re-calibrate the pH combination electrode (7).

6. The on-line analysis method of boric acid in primary coolant according to claim 5, characterized in that, The said Step One includes: Step 1.1: The three-way solenoid valve A (21) connects the pipeline between the three-way solenoid valve B (22) and the sample injection distribution device (1), and closes the pipeline connected to the drain pipe; the three-way solenoid valve B (22) connects the pipeline between the three-way solenoid valve A (21) and the metering tube (3), and closes the pipeline connected to the analysis cup (4). Step 1.2: The primary loop coolant sample water flows into the sample injection distribution device (1), and successively flows through the three-way solenoid valve A (21) and the three-way solenoid valve B (22), and enters the metering tube (3). The primary loop coolant sample water exceeding the volume of the metering tube (3) flows out from the upper part of the metering tube (3). Step 1.3: When the metering tube (3) is filled, the three-way solenoid valve B (22) closes the pipeline communicating with the three-way solenoid valve A (21), and the three-way solenoid valve A (21) connects to the drain pipe, and the drain pipe discharges the primary loop coolant sample water flowing in from the sample injection distribution device (1).

7. The on-line analysis method for boric acid in the primary coolant according to claim 5, characterized in that, The said Step Two includes: Step 2.1: The three-way solenoid valve C (23) connects the demineralized water inlet pipe and the analysis cup (4). The demineralized water enters the analysis cup (4) through the brine inlet pipe. After 10 seconds, the three-way solenoid valve C (23) closes the connection with the demineralized water inlet pipe. Step 2.2: The magnetic bead stirrer (6) stirs the demineralized water for 20 seconds. Step 2.3: The three-way solenoid valve C (23) connects the demineralized water outlet pipe and the analysis cup (4), and discharges the demineralized water from the analysis cup (4). Step 2.4: Repeat Steps 2.1 to 2.3 again. Step 2.5: The three-way solenoid valve C (23) closes the pipeline connected to the analysis cup (4), and the three-way solenoid valve B (22) connects the pipeline between the metering tube (3) and the analysis cup (4), and the primary loop coolant sample water in the metering tube (3) enters the analysis cup (4).

8. The on-line analysis method of boric acid in the primary coolant according to claim 5, characterized in that, In the said Step 3.2, the stirring duration of the magnetic bead stirrer (6) is 30 seconds.

9. The online analysis method of boric acid in the primary coolant according to claim 5, characterized in that The said Step Five includes: Step 5.1: 5 seconds after the measurement of the boric acid concentration is completed, the three-way solenoid valve C (23) connects the demineralized water outlet pipe and the analysis cup (4), and discharges the solution in the analysis cup (4). Step 5.2: The three-way solenoid valve C (23) closes the connection with the demineralized water outlet pipe, and the three-way solenoid valve C (23) connects the demineralized water inlet pipe and the analysis cup (4), injecting demineralized water into the analysis cup (4); after 10 seconds, ensure that the pH composite electrode (7) is immersed in the demineralized water, and close the connection between the three-way solenoid valve C (23) and the brine inlet pipe.

10. The on-line analysis method of boric acid in primary coolant according to claim 5, characterized in that, The said step six includes: Step 6.1: Configure standard pH buffer solutions with pH values of 4.00, 6.86, and 9.

18. Step 6.2: Take out the pH composite electrode (7) from the analysis cup (4), set the pH composite electrode (7) to the three-point calibration mode, rinse the pH composite electrode (7) with demineralized water and wipe it clean with filter paper. Step 6.3: Calibrate the pH composite electrode (7) by placing it into the standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18 respectively. Step 6.4: Retest the pH composite electrode (7) by placing it into the standard pH buffer solutions with pH values of 4.00, 6.86, and 9.18 respectively, and check whether the measured pH value error of the pH composite electrode (7) is within the range of ±0.

05. If the pH value error exceeds ±0.05, repeat steps 6.1 to 6.

4. Step 6.5: Reinstall the pH composite electrode (7) into the analysis cup (4).

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