Method for measuring dissolved nitrogen in reactor primary loop coolant

Abstract

The invention discloses a method for measuring dissolved nitrogen in a primary loop coolant of a reactor, which comprises the following steps of: S1, separating the dissolved nitrogen in the primary loop coolant by adopting a phase separator to obtain mixed gas containing nitrogen; s2, analyzing through a gas chromatograph to obtain the nitrogen content in the mixed gas; and S3, calculating the content of dissolved nitrogen in the primary loop coolant according to the nitrogen content. The invention provides an analysis method for nuclear power plant primary loop coolant dissolved nitrogen. The scheme is simple in operation process, accurate and sensitive in measurement result, capable of meeting the requirement for measuring the dissolved nitrogen in the primary loop, and capable of being popularized and used in other nuclear power plants needing to measure the dissolved nitrogen.

Description

Technical Field

[0001] This invention relates to the field of reactor gas analysis technology, and in particular to a method for measuring dissolved nitrogen in the primary coolant of a reactor. Background Technology

[0002] 14 C is a radioactive isotope that releases beta particles. With a half-life of 5730 years, it can release beta particles at close range within organisms after entering the environment, potentially damaging intracellular molecules, causing DNA strand breaks, base mutations, and other environmental hazards. (This is relevant to light water pressurized water reactors.) 14 One of the important sources of carbon is nitrogen ( 14 N, (n, p), 14 C) Activation: If the dissolved nitrogen content in the primary coolant increases from 10 ppm to 40 ppm, then the activation will produce... 14 C increased by 0.04 to 0.19 TBq / (GWe) a) It accounts for a portion of the nuclear power plant's output 14 A significant portion of C. 14 Carbon (C) is released into the environment in gaseous (such as CO2, CH4, or other organic compounds) or liquid form, participating in the carbon cycle and entering the food chain through plant photosynthesis. Alternatively, it can enter the human body through respiration or food, binding with organic molecules and potentially causing radiation damage to cells and genetic material. With increasingly stringent environmental protection requirements, accurate dissolved nitrogen content data of the primary coolant is needed during the environmental impact assessment phase of nuclear power plant site selection for evaluation. 14 Annual emissions (C). Furthermore, during normal operation of a nuclear power plant, the dissolved nitrogen content in the primary loop must also be controlled to maintain emissions levels. 14 C emissions. Therefore, during normal operation of nuclear power plants, it is necessary to increase the measurement of dissolved nitrogen in the primary coolant in order to more accurately assess [the situation]. 14 The amount of carbon generated requires accurate measurement of the dissolved nitrogen content in the primary coolant.

[0003] Nitrogen is chemically inert and is often used as an inert covering gas and pressure regulating medium in the primary loop of nuclear power plants. It is the most widely used gas. The amount of nitrogen dissolved in the primary loop is not trace, but considerable enough to be analyzed. Therefore, it is feasible to design a measurement method to analyze dissolved nitrogen in the primary loop coolant under the current conditions. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for measuring dissolved nitrogen in the primary coolant of a reactor.

[0005] The technical solution adopted by this invention to solve its technical problem is: to provide a method for measuring dissolved nitrogen in the primary coolant of a reactor, comprising the following steps: S1. A phase separation device is used to separate dissolved nitrogen from the primary coolant to obtain a nitrogen-containing mixed gas; the carrier gas used in the phase separation device is argon, and the mixed gas includes nitrogen and argon. S2. The nitrogen content in the mixed gas is obtained by gas chromatography analysis; S3. Calculate the dissolved nitrogen content in the primary coolant based on the nitrogen content; The dissolved nitrogen content in the primary coolant is calculated using formulas (I) and (II): W N2 =(C N2 ×V1×P×M×10) / (P0×V ×V2) (I) C N2 =C N2色谱 -3.727×C O2色谱 (two) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2 Nitrogen content, %; V is the molar volume of nitrogen under standard conditions, 22.4 L / mol; M is the molar volume of nitrogen, 28.02 g / mol; 10 is the residual coefficient after unit conversion; C N2色谱 The nitrogen content measured by gas chromatography, %; C O2色谱 The oxygen content is measured by a gas chromatograph.

[0006] Preferably, step S1 includes: S1.1. The primary coolant is circulated into the degasser of the phase separation unit; S1.2 After circulation, close the inlet and outlet passages of the degasser, open the carrier gas pipeline, and introduce argon gas into the degasser for bubbling, so that the gas in the primary coolant is separated out and flows upward into the decanter; S1.3. Obtain the mixed gas separated from the primary coolant through the sampler connected to the decanter.

[0007] Preferably, before step S1, the phase separation device is purged with argon gas to remove impurity gases.

[0008] Preferably, in step S3, formula (ii) represents the deduction of nitrogen gas mixed into the air by the sampler of the phase separation device; the nitrogen gas mixed in is deducted at 3.727 times the oxygen content according to the ratio of nitrogen gas to oxygen gas in the atmosphere. Step S2 also includes: The oxygen content in the mixed gas was obtained by gas chromatography analysis. In step S3, the nitrogen content mixed in the sampler is calculated based on the nitrogen content being 3.727 times that of the oxygen content; according to formula (II), the nitrogen content obtained in step S2 is subtracted from the above nitrogen content to obtain the nitrogen content in the primary coolant, and then the dissolved nitrogen content in the actual primary coolant is calculated according to formula (I).

[0009] Preferably, the method for measuring dissolved nitrogen in the reactor primary coolant is to perform at least two tests and take the average value.

[0010] This invention provides another method for measuring dissolved nitrogen in the primary coolant of a reactor, comprising the following steps: S1. A phase separation device is used to separate dissolved nitrogen from the primary coolant to obtain a nitrogen-containing mixed gas; the carrier gas used in the phase separation device is argon, and the mixed gas includes nitrogen and argon. S2. The nitrogen content in the mixed gas is obtained by gas chromatography analysis; S3. Calculate the dissolved nitrogen content in the primary coolant based on the nitrogen content; The dissolved nitrogen content in the primary coolant is calculated using formula (iii): W N2 =(C N2色谱 (×V1×P×M×10) / (P0×V ×V2) (III) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2色谱 The nitrogen content measured by gas chromatograph is %; V is the molar volume of nitrogen under standard conditions, 22.4 L / mol; M is the molar volume of nitrogen, 28.02 g / mol; 10 is the residual coefficient after unit conversion.

[0011] Preferably, step S1 includes: S1.1. The primary coolant is circulated into the degasser of the phase separation unit; S1.2 After circulation, close the inlet and outlet passages of the degasser, open the carrier gas pipeline, and introduce argon gas into the degasser for bubbling, so that the gas in the primary coolant is separated out and flows upward into the decanter; S1.3. Obtain the mixed gas separated from the primary coolant through the sampler connected to the decanter.

[0012] Preferably, before step S1, the phase separation device is purged with argon gas to remove impurities.

[0013] Preferably, the sampler is directly connected to the gas chromatograph, and the gas chromatograph acquires and analyzes the mixed gas in the sampler online.

[0014] Preferably, the method for measuring dissolved nitrogen in the reactor primary coolant is to perform at least two tests and take the average value.

[0015] The beneficial effects of this invention are: it provides an analytical method for dissolved nitrogen in the primary coolant of a nuclear power plant; the operation process is simple, the analytical method and the measurement of dissolved nitrogen in the primary coolant can be completed in one go, the measurement results are accurate and sensitive, it can meet the requirements for measuring dissolved nitrogen in the primary coolant, and it can be promoted and used in other nuclear power plants that need to measure dissolved nitrogen.

[0016] The measurement results are in line with expectations and meet the environmental assessment requirements for C-14 (i.e. 14 C) Activity design requirements. Attached Figure Description

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic diagram of the phase separation device used in this invention; Figure 2 This is a curve showing the content of dissolved nitrogen in the primary loop measured over a long period of time using the present invention. Detailed Implementation

[0018] refer to Figure 1 A method for measuring dissolved nitrogen in the primary coolant of a reactor according to an embodiment of the present invention includes the following steps: S1. A phase separation device is used to separate the dissolved nitrogen from the primary coolant to obtain a nitrogen-containing mixed gas.

[0019] Commonly used phase separation devices are designed only for analyzing hydrogen and oxygen, and typically use nitrogen as the carrier gas, thus failing to analyze nitrogen in the primary loop. To enable the analysis of nitrogen in the primary loop, this invention uses argon as the carrier gas, which is readily available, inexpensive, and has sufficiently high inertness and physical properties compared to nitrogen.

[0020] Therefore, the phase separation device uses argon as the carrier gas, and the separated mixed gas includes nitrogen and argon.

[0021] like Figure 1As shown, the phase separation device includes a degasser 10, a decanter 20, a sampler 30, and piping. The degasser 10 is connected to an inlet water pipe 11 and an outlet water pipe 12. The decanter 20 is connected to the degasser 10 via a separation gas pipe 21, and the sampler 30 is connected above the decanter 20. The degasser 10 is also connected to a carrier gas source via a carrier gas pipe 13. The carrier gas source can be an argon cylinder or an argon tank.

[0022] To simplify pipeline connections, the effluent pipeline 12 and decanter 20 are connected to deaerator 10 via a first three-way valve 31, which switches between the effluent pipeline 12 and the separated gas pipeline 21. The inlet pipeline 11 and outlet pipeline 14 are connected to deaerator 10 via a second three-way valve 32, which also switches between the inlet pipeline 11 and the outlet pipeline 14. The carrier gas pipeline 13 can be connected to deaerator 10 and decanter 20 via a third three-way valve 33, which connects deaerator 10 or decanter 20 to the carrier gas source. A flow meter 15 is installed on carrier gas pipeline 13 to monitor the flow rate of carrier gas entering deaerator 10 or decanter 20.

[0023] Understandably, each pipeline is also equipped with valves to control on / off states, flow rates, etc. Pressure gauges are installed on the inlet water pipeline 11 and / or the outlet water pipeline 12, and pressure gauges are installed on the carrier gas pipeline 13.

[0024] Before step S1, the phase separation device is purged with argon gas to remove impurities. The purging process may include two stages. In the first stage, a first three-way valve 31 connects the decanter 20 and the degasser 10, a second three-way valve 32 connects the degasser 10 and the drain line 14, and a third three-way valve 33 connects the carrier gas line 13 and the decanter 20. Argon gas is introduced, passing through the carrier gas line 13 into the decanter 20, then into the degasser 10, and finally exiting through the drain line 14. In the second stage, a third three-way valve 33 connects the carrier gas line 13 and the degasser 10, and a second three-way valve 32 connects the degasser 10 and the drain line 14. Argon gas is introduced, passing through the carrier gas line 13 into the degasser 10, and finally exiting through the drain line 14.

[0025] In one embodiment, step S1 further includes: S1.1 The primary coolant is circulated into the degasser 10 of the phase separation device so that the entire degasser 10, the inlet pipe 11 and the outlet pipe 12 are filled with the primary coolant.

[0026] S1.2 After circulation, close the inlet and outlet passages of the degasser 10 (i.e., the inlet water pipe 11 and the outlet water pipe 12), open the carrier gas pipe 13, and introduce argon gas into the degasser 10 to bubble, so that the gas in the primary coolant is separated out and flows upward into the decanter 20.

[0027] S1.3. Obtain the mixed gas separated from the primary coolant through the sampler 30 connected to the decanter 20.

[0028] Combination Figure 1 The phase separation device shown in step S1 is operated as follows: The first three-way valve 31 connects the outlet water pipe 12 and the deaerator 10, and the second three-way valve 32 connects the inlet water pipe 11 and the deaerator 10. Open the valves on the inlet water pipe 11 and the outlet water pipe 12 to allow the primary coolant to enter the deaerator 10 through the inlet water pipe 11 until it is full and then output from the outlet water pipe 12. Continuously introduce the primary coolant to circulate it in and out of the deaerator 10 for a period of time (e.g., 10 minutes), and then close the valves on the inlet water pipe 11 and the outlet water pipe 12. The first three-way valve 31 connects the degasser 10 and the decanter 20, and the third three-way valve 33 connects the carrier gas pipeline 13 and the degasser 10. Argon gas is introduced into the degasser 10 through the carrier gas pipeline 13 for bubbling. The gas in the primary coolant, together with the carrier gas, is separated from the liquid state and enters the decanter 20 from the top of the degasser 10, and then enters the sampler 30 from the top.

[0029] After the sampler 30 obtains a predetermined volume of mixed gas, it is taken out from the decanter 20.

[0030] S2. The mixed gas obtained by the sampler 30 is analyzed by gas chromatography to obtain the nitrogen content C in the mixed gas. N2色谱 .

[0031] Gas chromatographs can also analyze and obtain the oxygen content (C) in mixed gases as needed. O2色谱 .

[0032] S3. Calculate the dissolved nitrogen content W in the primary coolant based on the nitrogen content. N2 .

[0033] In one embodiment, after sampling, the sampler 30 removes the sample from the decanter 20 and then connects it to the gas chromatograph. Since air inevitably gets mixed into the sampler 30 and various connectors in the phase separation device, air interference needs to be subtracted to obtain more accurate measurement results. The subtraction method utilizes the fact that the oxygen and nitrogen ratios in the mixed air (containing 78.08% nitrogen and 20.95% oxygen) remain constant, and subtracts based on the multiple R of nitrogen volume fraction to oxygen volume fraction. The volume fractions of nitrogen and oxygen in the air are based on the standard dry air composition: nitrogen volume (V... N2 The oxygen content was 78.08%, and the oxygen volume (V) O2 The percentage was 20.95%.

[0034] Multiple R=V N2 / V O2 =78.08 / 20.95≈3.727.

[0035] The reason this deduction can be performed as described above is that the primary coolant, being hydrogen-covered, needs to maintain its reducing properties, thus its oxygen content is almost negligible. The oxygen content measured in the sample comes entirely from air; therefore, the nitrogen mixed into the sample via air can be deducted at 3.727 times the oxygen content. That is, deducting the nitrogen mixed into the air by the sampler 30 of the phase separation device: based on the ratio of nitrogen to oxygen in the atmosphere, the mixed nitrogen is deducted at 3.727 times the oxygen content.

[0036] According to the following formula (ii), subtract the nitrogen content mentioned above from the nitrogen content obtained in step S2 to obtain the nitrogen content C in the primary coolant. N2 Then, the dissolved nitrogen content W in the actual primary coolant is calculated according to formula (I). N2 .

[0037] Therefore, the dissolved nitrogen content in the primary coolant is calculated using formulas (i) and (ii): W N2 =(C N2 ×V1×P×M×10) / (P0×V ×V2) (I) C N2 =C N2色谱 -3.727×C O2色谱 (two) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2 Nitrogen content, %; V is the molar volume of nitrogen under standard conditions, 22.4 L / mol; M is the molar volume of nitrogen, 28.02 g / mol; 10 is the residual coefficient after unit conversion; C N2色谱 The nitrogen content measured by gas chromatography, %; C O2色谱 The oxygen content is measured by a gas chromatograph.

[0038] During the measurement process, the sampler should be evacuated to a minimum vacuum level before degassing, with the final degassing pressure being 1.5 bar. To reduce measurement bias, each sample should be analyzed twice and the average value taken during actual operation.

[0039] In another embodiment, the gas chromatograph is directly connected to the sampler 30 to achieve online sampling and measurement, avoiding air contamination. The dissolved nitrogen content in the primary coolant is calculated using formula (iii): W N2 =(C N2色谱(×V1×P×M×10) / (P0×V ×V2) (III) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2色谱 The nitrogen content measured by gas chromatograph is expressed in %; V is the molar volume of nitrogen under standard conditions, which is 22.4 L / mol; M is the molar volume of nitrogen, which is 28.02 g / mol; 10 is the residual coefficient after unit conversion.

[0040] During the measurement process, the sampler should be evacuated to a minimum vacuum level before degassing, with the final degassing pressure being 1.5 bar. To reduce measurement bias, each sample should be analyzed twice and the average value taken during actual operation.

[0041] In one preferred embodiment, the gas chromatograph used is the GC-950L gas chromatograph from Shanghai Haixin Chromatography Instrument Co., Ltd.

[0042] Utilizing the different partition coefficients of various gaseous components (such as H2, O2, and N2 (gas phase)) in the chromatographic column (stationary phase), a mixed sample is loaded into the column by a carrier gas (argon) for separation, and then detected one by one by a detector. Qualitative analysis is performed using the retention time of each component's chromatographic peak, and quantification is performed based on the peak height or peak area. A working curve is established using standard gases to calculate the content of each component in the sample. A quality control gas check must be performed before each gas analysis. The validity of the analytical results is determined by two factors: first, the deviation d% between the measured result of the quality control gas and the value marked on the quality control gas cylinder must be within ±10%; second, the parallel deviation d1% between two gas sample analyses must not exceed ±10%. When the gas sample analysis results meet these two conditions, the analysis results are considered valid, and the average of the two analysis results is taken as the final analysis result for this sample.

[0043] Therefore, steps S1-S3 of the above embodiments are performed at least twice, and the average value is taken as the final result.

[0044] In an actual measurement, the standard gas composition used by the instrument was approximately 2% He, 2% H2, 2% O2, 2% N2, and the remainder was Ar.

[0045] The composition of the quality control gas is as follows: He is approximately 1%, H2 is approximately 1%, O2 is approximately 1%, N2 is approximately 1%, and the remainder is Ar.

[0046] The instrument detection limits are: H2: 0.03%, H2: 0.03%, O2: 0.10%, N2: 0.10%.

[0047] After long-term measurement of dissolved nitrogen in the primary loop, the content curve was obtained as follows: Figure 2 As shown, the measured dissolved nitrogen content values ​​of the primary loop are stable, with an average value of approximately 14 mg / kg, a maximum value of 22.9 mg / kg, and an overall standard deviation of 2.6 mg / kg, which meets the measurement accuracy requirements for environmental assessment.

[0048] In summary, the implementation of the measurement method of this invention establishes an analytical method for dissolved nitrogen in the primary coolant of nuclear power plants. This method is simple to operate, and the analysis and measurement of primary coolant dissolution can be completed in one step. The measurement results are accurate and sensitive, meeting the requirements for primary coolant dissolution measurement. It can be promoted and used in other nuclear power plants where dissolved nitrogen measurement is required.

[0049] The measurement results are in line with expectations and meet the environmental assessment requirements for C-14 activity design.

[0050] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for measuring dissolved nitrogen in the primary coolant of a reactor, characterized in that, Includes the following steps: S1. A phase separation device is used to separate dissolved nitrogen from the primary coolant to obtain a nitrogen-containing mixed gas; the carrier gas used in the phase separation device is argon, and the mixed gas includes nitrogen and argon. S2. The nitrogen content in the mixed gas is obtained by gas chromatography analysis; S3. Calculate the dissolved nitrogen content in the primary coolant based on the nitrogen content; The dissolved nitrogen content in the primary coolant is calculated using formulas (I) and (II): W N2 = (C N2 × V1 × P × M × 10) / (P0 × V × V2) (1) C N2 =C N2色谱 -3.727×C O2色谱 (two) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2 Nitrogen content, %; V is the molar volume of nitrogen under standard conditions, 22.4 L / mol; M is the molar volume of nitrogen, 28.02 g / mol; 10 is the residual coefficient after unit conversion; C N2色谱 The nitrogen content measured by gas chromatography, %; C O2色谱 The oxygen content is measured by a gas chromatograph.

2. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 1, characterized in that, Step S1 includes: S1.

1. The primary coolant is circulated into the degasser of the phase separation unit; S1.2 After circulation, close the inlet and outlet passages of the degasser, open the carrier gas pipeline, and introduce argon gas into the degasser for bubbling, so that the gas in the primary coolant is separated out and flows upward into the decanter; S1.

3. Obtain the mixed gas separated from the primary coolant through the sampler connected to the decanter.

3. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 2, characterized in that, Before step S1, the phase separation device is purged with argon gas to remove impurity gases.

4. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 1, characterized in that, In step S3, formula (ii) means deducting nitrogen from the air mixed in by the sampler of the phase separation device; according to the ratio of nitrogen to oxygen in the atmosphere, the mixed nitrogen is deducted at 3.727 times the oxygen content. Step S2 also includes: The oxygen content in the mixed gas was obtained by gas chromatography analysis. In step S3, the nitrogen content mixed in the sampler is calculated based on the nitrogen content being 3.727 times that of the oxygen content; according to formula (II), the nitrogen content obtained in step S2 is subtracted from the above nitrogen content to obtain the nitrogen content in the primary coolant, and then the dissolved nitrogen content in the actual primary coolant is calculated according to formula (I).

5. The method for measuring dissolved nitrogen in the reactor primary coolant according to any one of claims 1-4, characterized in that, The method for measuring dissolved nitrogen in the reactor primary coolant shall be tested at least twice and the average value shall be taken.

6. A method for measuring dissolved nitrogen in the primary coolant of a reactor, characterized in that, Includes the following steps: S1. A phase separation device is used to separate dissolved nitrogen from the primary coolant to obtain a nitrogen-containing mixed gas; the carrier gas used in the phase separation device is argon, and the mixed gas includes nitrogen and argon. S2. The nitrogen content in the mixed gas is obtained by gas chromatography analysis; S3. Calculate the dissolved nitrogen content in the primary coolant based on the nitrogen content; The dissolved nitrogen content in the primary coolant is calculated using formula (iii): W N2 =(C N2色谱 (×V1×P×M×10) / (P0×V ×V2) (III) Among them: W N2 V1 is the dissolved nitrogen content in the primary coolant, in mg / kg; V2 is the volume of the sampler in the phase separation device, in cm³. 3 V2 is the volume of the degasser in the phase separation device, in cm³. 3 P0 is standard atmospheric pressure; P is the final degassing pressure reading of the sampler in the phase separation device, in bar; C N2色谱 The nitrogen content measured by gas chromatograph is %; V is the molar volume of nitrogen under standard conditions, 22.4 L / mol; M is the molar volume of nitrogen, 28.02 g / mol; 10 is the residual coefficient after unit conversion.

7. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 6, characterized in that, Step S1 includes: S1.

1. The primary coolant is circulated into the degasser of the phase separation unit; S1.2 After circulation, close the inlet and outlet passages of the degasser, open the carrier gas pipeline, and introduce argon gas into the degasser for bubbling, so that the gas in the primary coolant is separated out and flows upward into the decanter; S1.

3. Obtain the mixed gas separated from the primary coolant through the sampler connected to the decanter.

8. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 7, characterized in that, Before step S1, the phase separation device is purged with argon gas to remove impurities.

9. The method for measuring dissolved nitrogen in the reactor primary coolant according to claim 7, characterized in that, The sampler is directly connected to the gas chromatograph, which acquires and analyzes the mixed gas in the sampler online.

10. The method for measuring dissolved nitrogen in the reactor primary coolant according to any one of claims 7-9, characterized in that, The method for measuring dissolved nitrogen in the reactor primary coolant shall be tested at least twice and the average value shall be taken.

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