System and method for monitoring leakage of heat supply system of high-temperature gas cooled reactor unit

Abstract

The invention relates to the technical field of nuclear power plant leakage monitoring, aims to solve the problem of high-precision monitoring of leakage of secondary side heating steam to a tertiary side heat supply loop through a heat exchanger, and discloses a system and a method for monitoring leakage of a heat supply system of a high-temperature gas cooled reactor unit. The system comprises a demineralized water delivery pump, a preheater, a deaerator, an evaporator and a superheater which are sequentially connected through a single-row heat supply pipeline, the obtained leakage rate of a heat supply heat exchanger is compared with the allowable leakage rate, and according to the comparison result, the corresponding actions such as reducing the heat supply load or stopping the row for overhauling are adopted. According to the invention, the working efficiency and timeliness of leakage detection are improved, so that economic, efficient and safe operation of the heat supply unit is guaranteed.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear power plant leakage monitoring, and in particular to a system and method for high-precision leakage monitoring of heating systems of high-temperature gas-cooled reactors, sodium-cooled fast reactors, heavy water reactors and the like. Background Art

[0002] Using nuclear energy to replace coal-fired cogeneration units for heating can achieve the goals of zero coal consumption and zero air pollution emissions, implement the national green and low-carbon energy development strategy, and effectively support the sustainable development of high-energy-consuming industries such as petrochemicals. At present, there are cases in China where pressurized water reactors and other units are used for civil heating and industrial heating. There are also many heating technology solutions for other reactor types such as high-temperature gas-cooled reactors, sodium-cooled fast reactors, and heavy water reactors. The pressurized water reactor + high-temperature gas-cooled reactor combined heating solution that a nuclear heating power plant plans to adopt has pushed the large-scale industrial application of nuclear energy to a new level. In order to ensure the safety and reliability of nuclear steam, nuclear heating processes mostly use simple wall heat exchange technology, using a series of heat exchangers such as preheaters, deaerators, evaporators, and superheaters to achieve heat transfer and isolate the working fluid.

[0003] If these heat exchangers leak during operation, the temperature, pressure and flow of the steam generated will not meet the user's requirements, affecting the normal operation of the heating system and causing economic losses. In addition, the substances generated by the leakage will enter the user side through the heating circuit, which will bring some potential consequences.

[0004] At present, commonly used leakage monitoring methods such as flow meters and pressure gauges can only meet the monitoring requirements of larger flow leakage (the highest monitoring accuracy of common monitoring methods such as flow meters can only reach 1%). It is necessary to add high-precision leakage monitoring methods to detect trace leaks in time.

[0005] Therefore, there is an urgent need for a system and method for identifying and detecting trace leaks from the secondary heating circuit (secondary circuit) to the tertiary heating circuit (third circuit) under the existing water quality conditions of units such as high-temperature gas-cooled reactors, sodium-cooled fast reactors, and heavy water reactors. Summary of the invention

[0006] The object of the present invention is to provide a system and method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit, so as to solve the problem of high-precision monitoring of leakage of secondary heating steam through a heat exchanger to a tertiary heating circuit.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] On the one hand, the present invention provides a system for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit, comprising a single-row or multiple-row parallel heating pipeline that can provide external steam with the same or different parameters, a desalted water delivery pump, a preheater, a deaerator, an evaporator and a superheater connected in sequence by the single-row heating pipeline, wherein the preheater, the evaporator and the superheater can be one-stage or multi-stage, and the multi-stage preheater can also be arranged after the deaerator and before the evaporator, a sampling point after the desalted water delivery pump is provided between the desalted water delivery pump and the preheater, a sampling point after the preheater is provided between the preheater and the deaerator, a sampling point after the deaerator is provided between the deaerator and the evaporator, a sampling point after the evaporator is provided between the evaporator and the superheater, and a sampling point after the superheater is provided after the superheater. The heating circuit can also be set as a multi-row heating pipeline, and steam with the same or different parameters can be provided in parallel to supply heat to the outside according to user needs.

[0009] In some embodiments, the preheater is provided with a first steam pipeline, the second-circuit heating steam is introduced into the first steam pipeline, and a second-circuit heating steam sampling point is provided at the outlet of the first steam pipeline.

[0010] In some embodiments, the deaerator is provided with a second steam pipeline, the second steam pipeline is fed with secondary circuit heating steam, and a secondary circuit heating steam sampling point is provided at the outlet of the second steam pipeline.

[0011] In some embodiments, the evaporator is provided with a third steam pipeline, the third steam pipeline is fed with secondary circuit heating steam, and a secondary circuit heating steam sampling point is provided at the outlet of the third steam pipeline.

[0012] In some embodiments, the superheater is provided with a fourth steam pipeline, the fourth steam pipeline is fed with secondary circuit heating steam, and a secondary circuit heating steam sampling point is provided at the outlet of the fourth steam pipeline.

[0013] In some embodiments, the outlet of the superheater is connected to a fifth pipeline, and a post-superheater sampling point is provided on the fifth pipeline.

[0014] In another aspect, the present invention provides a method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit, comprising:

[0015] Step 1: Obtain the activity value C of tritium penetration in the three-circuit heating circuit under equilibrium state 0 ;

[0016] Step 2: Analyze the tritium background activity at the sampling point after the desalted water delivery pump to obtain the measured tritium activity value C of the desalted water at the inlet of the heating circuit 2 ;

[0017] Step 3: Analyze the tritium activity at the secondary circuit heating steam inlet sampling point and the deaerator heating steam sampling point to obtain the tritium activity measurement value C of the secondary circuit heating steam 二回路加热蒸汽 :C 11 , C 13 , C 15 and C 除氧器加热蒸汽 :C 17 ; The heating steam pressure of the secondary circuit is greater than that of the heating circuit. When leakage occurs, only the secondary circuit will leak to the heating circuit. The steam of the secondary circuit heats the evaporator, superheater and preheater in sequence. The tritium activity in the steam of the secondary circuit is the same at different positions. Usually, only one value needs to be measured.

[0018] Step 4: Analyze the sampling points after the preheater, the evaporator, the superheater, and the deaerator to obtain the tritium activity value C after the heat exchanger and the deaerator of each heating circuit. 换热器后 :C 4 , C 8 , C 10 and C 除氧器后 :C 6 ;

[0019] Step 5: If only one heat exchanger in a single-row heating pipeline is leaking, that is, only one tritium activity value after the heating heat exchanger is greater than the inlet tritium activity value, according to (C 换热器后 -C 0 -C 2 )×L 换热器后流量 =C 二回路加热蒸汽 ×L 二回路加热蒸汽泄漏流量 Since the leakage flow of the secondary heating steam is much smaller than the heat exchanger flow, the leakage rate Q = L 二回路加热泄漏流量 / L 换热器后流量 =(C 换热器后 -C 0 -C 2 ) / C 二回路加热蒸汽 If only a single heat exchanger in the heating circuit is leaking, enter the corresponding analysis data and calculate the leakage rate Q of each heat exchanger in each heating circuit (referring to the preheater, evaporator, and superheater) in turn;

[0020] Step 6: If there are multiple heat exchangers (heat exchange equipment) leaking in a single heating pipeline, that is, the tritium activity values ​​after multiple heat exchangers are greater than the inlet tritium activity values, the actual total tritium activity of the next heat exchanger needs to be subtracted from the total tritium activity of the previous heat exchange equipment;

[0021] 1) Superheater leakage rate: (L 10 ×C 10 -L 8 ×C 8 )=L 11 ×C11 , L 10 =(L 8 +L 11 ), because L 11 The leakage flow is much smaller than L 8 Flow rate, L 10 ≈L 8 , so the leakage rate Q = L 11 / L 10 =(C 10 -C 8 ) / C 11 ;

[0022] 2) Evaporator leakage rate: (L 8 ×C 8 -L 6 ×C 6 )=L 13 ×C 13 , L 8 =(L 6 +L 13 ), because L 13 The leakage flow is much smaller than L 6 Flow rate, L 8 ≈L 6 , so the leakage rate Q = L 13 / L 8 =(C 8 -C 6 ) / C 13 ;

[0023] 3) The deaerator is mixed heating, so there is no need to calculate the leakage;

[0024] 4) The preheater is the first heat exchanger, and the calculation method is the same as step 5.

[0025] Step 7: Compare the obtained leakage rate Q (leakage rate Q) of the heat exchanger with the allowable leakage rate, and take corresponding actions such as reducing the heating load or stopping the system for maintenance based on the comparison results.

[0026] In some embodiments, the tritium background activity at the sampling point after the deionized water delivery pump is analyzed by an online or offline liquid scintillation analyzer.

[0027] In some embodiments, the tritium activity of the secondary loop heating steam and the deoxygenation heating steam sampling points is analyzed by an online or offline liquid scintillation analyzer.

[0028] In some embodiments, the calculation formula for the leakage rate Q of a single heat exchanger in a single row is as follows:

[0029] Q=(C 换热器后 -C 0 -C 2 ) / C 二回路加热蒸汽 ;

[0030] In some embodiments, the calculation formula for the leakage rate Q of a single heat exchanger when multiple heat exchangers in a single row leak simultaneously is as follows:

[0031] Q=(C 后一个换热器后 -C 前一个换热器后 ) / C 后一个换热器二回路加热蒸汽 ;

[0032] In the formula, C 换热器后 is the tritium measurement value after the heat exchanger in the heating circuit, C 二回路加热蒸汽 is the measured value of tritium in the secondary circuit heating steam, C 0 is the tritium penetration value of the heating circuit, C 2 It is the measured value of tritium in the raw water at the inlet of the heating circuit.

[0033] Compared with the prior art, the system and method for high-precision leakage monitoring of a unit heating system provided by the present invention have the following beneficial effects:

[0034] The detection accuracy of the present invention is significantly higher than that of commonly used leakage monitoring methods such as flow meters and pressure gauges. Since the tritium online / offline detection modules are configured for the secondary heating circuit (secondary circuit) and the tertiary heating circuit (third circuit), trace leaks can be identified and measured in real time and in a timely manner, which greatly improves the efficiency and timeliness of leakage detection, thereby ensuring the economical, efficient and safe operation of the heating unit.

[0035] In addition, the present invention can be applied to subsequent secondary circuit tritium-containing heating projects such as high-temperature gas-cooled reactors, sodium-cooled fast reactors, and heavy water reactors. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for the technical description.

[0037] Figure 1 A schematic diagram of the structure of a system for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit provided by the present invention;

[0038] Figure 2 A flow chart of a method for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit provided by the present invention.

[0039] Description of reference numerals:

[0040] 1. Demineralized water delivery pump; 2. Sampling point after demineralized water delivery pump; 3. Preheater; 4. Sampling point after preheater; 5. Deaerator; 6. Sampling point after deaerator; 7. Evaporator; 8. Sampling point after evaporator; 9. Superheater; 10. Sampling point after superheater; 11. Sampling point for inlet of heating steam of secondary circuit of superheater; 12. Sampling point for outlet of heating steam of secondary circuit of superheater; 13. Sampling point for inlet of heating steam of secondary circuit of evaporator; 14. Sampling point for outlet of heating steam of secondary circuit of evaporator; 15. Sampling point for inlet of heating steam of secondary circuit of preheater; 16. Sampling point for outlet of heating steam of secondary circuit of preheater; 17. Sampling point for outlet of heating steam of deaerator. DETAILED DESCRIPTION

[0041] The following is further explained in detail through specific implementation methods.

[0042] like Figure 1 As shown, the present invention provides a system for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit, comprising a desalted water delivery pump 1, a preheater 3, a deaerator 5, an evaporator 7, and a superheater 9. The system uses tritium online / offline detection technology to identify and detect a trace leakage from a secondary heating circuit to a tertiary heating circuit in a heating system of a high-temperature gas-cooled reactor, a sodium-cooled fast reactor, a heavy water reactor, etc.

[0043] The desalted water delivery pump 1 is connected to the preheater 3 through the first pipeline, and a sampling point 2 after the desalted water delivery pump is provided between the desalted water delivery pump 1 and the preheater 3 (the raw water for the desalted water for heating steam comes from seawater, and there is a certain background activity of tritium in the sea area near the power station). The preheater 3 is provided with a first heating steam pipeline for heating the desalted water for heating in the preheater. The first steam pipeline is connected to the secondary circuit heating steam 15 for heating the desalted water for heating in the preheater, and is also the sampling point for the heating steam inlet, for sampling and measuring the tritium activity at the heating steam inlet. A secondary circuit heating steam outlet sampling point 16 is provided at the outlet of the first steam pipeline.

[0044] The preheater 3 and the deaerator 5 are connected by a second pipeline, and a sampling point 4 after the preheater is provided on the second pipeline, and the tritium activity of the heating desalted water after the preheater is sampled and measured. A second steam pipeline is provided on the deaerator 5, and the heating desalted water is heated by a mixed method of heating steam for deoxygenation. The second steam pipeline is fed with heating steam for deoxygenation 17, and the heating steam for deoxygenation 17 is used to heat the heating desalted water in the deaerator, and is also a sampling point for the inlet of the heating steam, and the tritium activity of the inlet of the heating steam for deoxygenation is sampled and measured.

[0045] The deaerator 5 and the evaporator 7 are connected by a third pipeline, and a sampling point 6 after the deaerator is arranged on the third pipeline (sampling and measuring the tritium activity of the heating desalted water after the deaerator). A third heating steam pipeline is arranged on the evaporator 7, which is used to heat the heating desalted water in the evaporator. The third steam pipeline is connected to the secondary circuit heating steam 13, which is used to heat the heating desalted water in the evaporator. It is also the sampling point for the heating steam inlet, and the tritium activity of the heating steam inlet is sampled and measured. A sampling point 14 for the secondary circuit heating steam outlet is arranged at the outlet of the third steam pipeline.

[0046] The evaporator 7 and the superheater 9 are connected by a fourth pipeline, and a sampling point 8 after the evaporator is provided on the fourth pipeline, which is used to sample and measure the tritium activity of the heating steam after the evaporator. The superheater 9 is provided with a fourth heating steam pipeline, which is used to heat the heating steam in the superheater. The fourth steam pipeline leads to the secondary heating steam 11, which is used to heat the heating steam in the superheater and is also the heating steam inlet sampling point, for sampling and measuring the tritium activity of the heating steam inlet. A secondary heating steam outlet sampling point 12 is provided at the outlet of the fourth steam pipeline. The outlet of the superheater 9 is connected to the fifth pipeline, which leads to an external user. A sampling point 10 after the superheater is provided on the fifth pipeline, and the sampling point 10 after the superheater is used to sample and measure the tritium activity of the heating steam after superheating.

[0047] It should be noted that the chemical additives in the condensate-feed water-steam loop (secondary loop) of high-temperature gas-cooled reactors, sodium-cooled fast reactors, heavy water reactors and other units are generally mainly ammonia and hydrazine, and the chemical additives in the tertiary side heating loop (tertiary loop) are generally mainly ammonia and hydrazine. The chemical reagents added in both are the same and the concentrations are similar. It is impossible to judge trace leaks by detecting changes in the concentrations of these commonly used chemical reagents.

[0048] In the normal operation of the reactor loop (primary loop) of high temperature gas-cooled reactors, sodium-cooled fast reactors, heavy water reactors and other units, nuclear fuel will undergo ternary fission, and at the same time, the activation reaction of certain light elements with neutrons will produce a high concentration of tritium. Since tritium has a strong permeability under high temperature and high pressure conditions, it can pass through the steam generator and enter the condensate-feedwater-steam loop (secondary loop). Taking the high temperature gas-cooled reactor as an example, when the reactor is operating normally, the working pressure of the primary loop is 7MPa, and the outlet steam pressure of the steam generator is 14.3MPa, that is, the pressure of the primary loop is much lower than the pressure of the secondary loop. Therefore, under normal operating conditions, it is difficult for radioactive substances in the primary loop to leak into the secondary loop, so the radioactivity concentration in the secondary loop is very low; the radioactivity in the secondary loop mainly comes from the penetration of tritium in the primary loop system into the secondary loop, because tritium can penetrate metal (permeation) at high temperature, and it can even pass through the intact steam generator heat transfer tube wall into the secondary loop. For example, the preheating section and evaporation section of the heat transfer tube of a high-temperature gas-cooled reactor steam generator use 2.25Cr-1Mo, and the superheating section uses Incoloy800H. Correspondingly, the permeability of tritium through the steam generator heat transfer tube to the secondary circuit uses the data of Incoloy800H in the superheating section (the average temperature is 620℃), and the data of 2.25Cr-1Mo in the preheating section and evaporation section (the average temperature is 345℃). The design value of the secondary circuit leakage rate (total replacement rate) is 2.142t / h~21.42t / h. Through calculation, it is deduced that the equilibrium concentration of tritium in the secondary circuit water caused by the tritium penetration pathway is about 1.46×10 5 Bq / kg~1.46×10 6 Similarly, it can be calculated that the maximum value of tritium activity concentration in the heating circuit is about 1.10E+1Bq / kg~1.10E+00Bq / kg.

[0049] At present, the lower limit of tritium measured by offline or online tritium monitoring equipment (liquid scintillation analyzer) is less than tens of Bq / kg. Therefore, the tritium concentration after the heat exchanger can be detected to monitor the trace leakage of the secondary main steam to the tertiary heating circuit. The monitored leakage rate (measured by flow meter, the ratio of the flow rate of the secondary leakage entering the heating circuit to the flow rate of the heating circuit) can reach an accuracy of about 0.01%-0.001%.

[0050] Therefore, the present invention can achieve higher-precision measurement than common flow, pressure and other methods.

[0051] Furthermore, the total amount of tritium added to the heating circuit due to leakage is equal to the total amount of tritium leaked into the heating circuit:

[0052] If only one heat exchanger in a single-row heating pipeline leaks, that is, only one tritium activity value after the heating heat exchanger is greater than the inlet tritium activity value:

[0053] (C 换热器后 -C 0-C 2 )×L 换热器后流量 =C 二回路加热蒸汽 ×L 二回路加热蒸汽泄漏流量 (Formula 1)

[0054] The leakage rate is defined as:

[0055] Q=L 二回路加热蒸汽泄漏流量 / L 换热器后流量 ×100% (Formula 2)

[0056] Therefore, the leakage rate calculation formula is as follows:

[0057] Q=(C 换热器后 -C 0 -C 2 ) / C 二回路加热蒸汽 ×100% (Formula 3)

[0058] If there are multiple heat exchangers leaking in a single row of heating pipelines, that is, the tritium activity values ​​after multiple heat exchangers are greater than the inlet tritium activity values, take superheater 9 as an example:

[0059] (L 10 ×C 10 -L 8 ×C 8 )=L 11 ×C 11

[0060] L 10 =(L 8 +L 11 ), because L 11 The leakage flow is much smaller than L 8 Flow rate, L 10 ≈L 8 , so the leakage rate Q = L 11 / L 10 =(C 10 -C 8 ) / C 11 ×100%;

[0061] Where:

[0062] Q: leakage rate, %;

[0063] L 二回路加热蒸汽泄漏流量 : The leakage flow rate of heating steam in the secondary circuit of a certain heating exchanger, kg / h;

[0064] L 换热器后流量 : Flow rate after a certain heating heat exchanger, kg / h;

[0065] C 换热器后 : Tritium measurement value after a certain heating heat exchanger, Bq / kg;

[0066] C二回路加热蒸汽 : Tritium measurement value of heating steam in the secondary circuit of a certain heating exchanger, Bq / kg;

[0067] C 0 : Tritium penetration value of heating circuit, Bq / kg;

[0068] C 2 : Tritium measurement value of raw water at the inlet of heating circuit, Bq / kg.

[0069] Therefore, the present invention is used to realize high-precision monitoring of a trace leakage of a secondary circuit containing tritium main steam heating circuit of a high-temperature gas-cooled reactor, a sodium-cooled fast reactor, a heavy water reactor, etc.

[0070] In addition, based on the above-mentioned system for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit, the present invention also provides a method for monitoring leakage of a heating system of a high-temperature gas-cooled reactor unit, such as Figure 2 As shown, the following steps are included:

[0071] Step 1: Obtain the equilibrium activity value C of tritium penetration in the three-circuit heating circuit from the heating system manual 0 .

[0072] Step 2: Analyze the tritium background concentration at sampling point 2 after the desalted water delivery pump by online or offline liquid scintillation analyzer to obtain the tritium measurement value C of the desalted water at the inlet of the heating circuit. 2 .

[0073] Step 3: Analyze the tritium activity of the secondary circuit heating steam sampling points 11, 13, 15 and the deaerator heating steam sampling point 17 through online or offline liquid scintillation analysis (online liquid scintillation analysis will be added at the sampling point later, which can automatically sample and process the sample for analysis to obtain the measured value; offline refers to manual sampling back to the laboratory and using the laboratory liquid scintillation instrument to analyze the measured value) to obtain the tritium activity measurement value C of the secondary circuit heating steam. 二回路加热蒸汽 :C 11 , C 13 , C 15 and C 除氧器加热蒸汽 :C 17 .

[0074] Step 4: Analyze the sampling point 4 after the preheater, the sampling point 6 after the deaerator, the sampling point 8 after the evaporator, and the sampling point 10 after the superheater by online or offline liquid scintillation analyzer to obtain the tritium activity value C after the heat exchanger and the deaerator of each heating circuit. 换热器后 :C 4 , C 8 , C 10 and C 除氧器后 :C 6 .

[0075] Step 5: If only one heat exchanger in a single-row heating pipeline is leaking, that is, only one tritium activity value after the heating heat exchanger is greater than the inlet tritium activity value, according to (C 换热器后 -C 0 -C 2 )×L 换热器后流量 =C 二回路加热蒸汽 ×L 二回路加热蒸汽泄漏流量 Since the leakage flow of the secondary heating steam is much smaller than the heat exchanger flow, the leakage rate Q = L 二回路加热泄漏流量 / L 换热器后流量 =(C 换热器后 -C 0 -C 2 ) / C 二回路加热蒸汽 If only a single heat exchanger in the heating circuit is leaking, the corresponding analysis data is brought in to calculate the leakage rate Q of each heat exchanger (preheater 3, evaporator 7, superheater 9) in each heating circuit in turn.

[0076] Step 6: If there are multiple heating loop heat exchangers (heat exchange equipment) leaking in a single heating pipeline, that is, the tritium activity values ​​behind multiple heating heat exchangers are greater than the inlet tritium activity value, the actual total tritium activity of the next heating heat exchanger needs to be subtracted from the total tritium activity of the previous heat exchange equipment.

[0077] 1) Leakage rate of superheater 9: (L 10 ×C 10 -L 8 ×C 8 )=L 11 ×C 11 , L 10 =(L 8 +L 11 ), because L 11 The leakage flow is much smaller than L 8 Flow rate, L 10 ≈L 8 , so the leakage rate Q = L 11 / L 10 =(C 10 -C 8 ) / C 11 .

[0078] 2) Leakage rate of superheater 7: (L 8 ×C 8 -L 6 ×C 6 )=L 13 ×C 13 , L 8 =(L 6 +L 13 ), because L 13 The leakage flow is much smaller than L 6 Flow rate, L 8≈L 6 , so the leakage rate Q = L 13 / L 8 =(C 8 -C 6 ) / C 13 .

[0079] 3) Deaerator 5 is a mixed heating device, so there is no need to calculate the leakage.

[0080] 4) Preheater 3 is the first heat exchanger, and the calculation method is the same as step 5.

[0081] Step 7: Compare the obtained leakage rate Q (leakage rate Q) of the heat exchanger with the allowable leakage rate, and take corresponding actions such as reducing the heating load or stopping the system for maintenance based on the comparison results.

[0082] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit, characterized in that: The invention comprises a desalted water delivery pump (1), a preheater (3), a deaerator (5), an evaporator (7) and a superheater (9) which are connected in sequence through a single-row heating pipeline. A sampling point (2) after the desalted water delivery pump is provided between the desalted water delivery pump (1) and the preheater (3), a sampling point (4) after the preheater is provided between the preheater (3) and the deaerator (5), a sampling point (6) after the deaerator is provided between the deaerator (5) and the evaporator (7), and a sampling point (8) after the evaporator is provided between the evaporator (7) and the superheater (9).

2. The system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 1, characterized in that: The preheater (3) is provided with a first steam pipeline, into which secondary circuit heating steam (15) is introduced, and a secondary circuit heating steam sampling point (16) is provided at the outlet of the first steam pipeline.

3. The system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 1, characterized in that: The deaerator (5) introduces a small amount of deionized water (17) heated by a deoxygenation evaporator with the same tritium activity as the sampling point (2) after the deionized water delivery pump to perform mixed heating.

4. The system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 1, characterized in that: The evaporator (7) is provided with a third steam pipeline, the third steam pipeline is fed with secondary circuit heating steam (13), and a secondary circuit heating steam sampling point (14) is provided at the outlet of the third steam pipeline.

5. The system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 1, characterized in that: The superheater (9) is provided with a fourth steam pipeline, the fourth steam pipeline is fed with secondary circuit heating steam (11), and a secondary circuit heating steam sampling point (12) is provided at the outlet of the fourth steam pipeline.

6. The system for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 1, characterized in that: The outlet of the superheater (9) is connected to a fifth pipeline, and a post-superheater sampling point (10) is provided on the fifth pipeline.

7. A method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit, characterized in that: include: Step 1: Obtain the activity value C0 of tritium penetration in the three-circuit heating circuit under equilibrium state; Step 2: Analyze the tritium background activity at the sampling point (2) after the desalted water delivery pump to obtain the tritium measured activity value C2 of the desalted water at the inlet of the heating circuit; Step 3: Analyze the tritium activity of the secondary circuit heating steam sampling points (11, 13, 15) and the deaerator heating steam sampling point (17) to obtain the measured value of the tritium activity of the secondary circuit heating steam C 二回路加热蒸汽 :C 11 , C 13 , C 15 and C 除氧器加热蒸汽 :C 17 ; Step 4: Analyze the sampling point after the preheater (4), the sampling point after the evaporator (8), the sampling point after the superheater (10) and the sampling point after the deaerator (6) respectively to obtain the tritium activity value C after each heating circuit heat exchanger and deaerator 换热器后 :C4、C8、C 10 and C 除氧器后 :C6; Step 5: If only one heat exchanger in a single-row heating pipeline is leaking, according to (C 换热器后 -C0-C2)×L 换热器后流量 =C 二回路加热蒸汽 ×L 二回路加热蒸汽泄漏流量 , we get the leakage rate Q = L 二回路加热泄漏流量 / L 换热器后流量 =(C 换热器后 -C0-C2) / C 二回路加热蒸汽 If only a single heat exchanger in the heating circuit is leaking, the corresponding analysis data is brought in to calculate the leakage rate Q of each heat exchanger (3, 7, 9) in each heating circuit in turn; Step 6: If there are multiple leaking heat exchangers in a single heating pipeline, the total tritium activity of the last leaking heat exchanger needs to be subtracted from the total tritium activity of the first heat exchanger. Step 7: Compare the obtained leakage rate Q of the heat exchanger with the allowable leakage rate, and decide whether to reduce the heating load or shut down the system for maintenance based on the comparison result.

8. The method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 7, characterized in that: In step 2, the tritium background activity at the sampling point after the desalted water delivery pump is analyzed by an online or offline liquid scintillation analyzer.

9. The method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 7, characterized in that: In step 3, the tritium concentrations at the secondary loop heating steam and the deoxygenation heating steam sampling points are analyzed by an online or offline liquid scintillation analyzer.

10. The method for monitoring leakage of a heating system of a high temperature gas-cooled reactor unit according to claim 7, characterized in that: In step 5, the leakage rate Q is calculated as follows: Q=(C 换热器后 -C0-C2) / C 二回路加热蒸汽 ×100%; In step 6, the leakage rate Q is calculated as follows: Q=(C 后一个换热器后 -C 前一个换热器后 ) / C 后一个换热器二回路加热蒸汽 ×100%; In the formula, C 换热器后 is the tritium measurement value after the heat exchanger in the heating circuit, C 二回路加热蒸汽 is the tritium measurement value of the secondary circuit heating steam, C0 is the tritium penetration value of the heating circuit, and C2 is the tritium measurement value of the raw water at the inlet of the heating circuit.

Images