WATER QUALITY MONITORING METHOD FOR NUCLEAR HEATING DEVICES

Abstract

WATER QUALITY MONITORING METHOD FOR NUCLEAR HEATING DEVICE This disclosure provides a water quality monitoring method for a nuclear heating device, which includes: in the event that a plant in a nuclear heating project begins a flushing, the analysis and monitoring of the quality of the flushing water in a plurality of devices and piping in the plant of the nuclear heating project, where the plurality of devices includes a demineralized water tank, a feedwater tank, a primary preheater, a deaerator, an evaporator and a superheater; in the event that the plant of the nuclear heating project is operating normally, the analysis and monitoring of the water quality from a plurality of sampling positions in the plant of the nuclear heating project;and in the event that the nuclear heating project plant is shut down, the maintenance of the plurality of devices and piping in the nuclear heating project plant. According to this disclosure, different objectives and axes of water quality monitoring at different stages of a plant in a nuclear heating project are defined, the technical problem of ensuring that the deposition of corrosion products on the heat transfer tubes on both sides of a heat conversion device in this process is as low as possible to reduce corrosion and scaling of the heat transfer tubes is solved in the prior art. Summary figure: Fig. 1;

Description

Title of the invention: METHOD FOR MONITORING WATER QUALITY FOR NUCLEAR HEATING DEVICES technical field

[0001] This disclosure falls within the technical field of water quality monitoring for heating devices, and more specifically relates to a method for monitoring water quality for a nuclear heating device. PRIOR TECHNOLOGY

[0002] According to nuclear heating projects, industrial steam is produced by heating industrial feedwater with steam from a secondary circuit produced in a nuclear power plant using a thermal conversion device. To ensure the safety and economy of this process, minimizing the deposition of corrosion products on the heat transfer tubes on both sides of the thermal conversion device in this process, in order to reduce corrosion and scaling of the heat transfer tubes, has become an urgent technical problem to solve. SUMMARY

[0003] To this end, one embodiment of the present disclosure aims to provide a method for monitoring water quality for a nuclear heating device. Different purposes and axes of water quality monitoring at different stages of a power plant in a nuclear heating project are defined. The technical problem of how to ensure that the deposition of corrosion products on the heat transfer tubes on both sides of a thermal conversion device in this process is as low as possible to reduce corrosion and scaling of the heat transfer tubes is solved in the prior art.

[0004] This disclosure provides a method for monitoring water quality for a nuclear heating device, which includes: in the case where a power plant in a nuclear heating project begins a flushing operation, the analysis and monitoring of the flushing water quality in a plurality of devices and piping in the power plant in the nuclear heating project to ensure that the flushing water quality in the plurality of devices and piping in the power plant in the nuclear heating project meets a corresponding water quality indicator, where the plurality of devices includes a demineralized water tank, a feedwater tank, a primary preheater, a deaerator, an evaporator, and a superheater; in the case where the power plant energy in the nuclear heating project is operating normally, the analysis and monitoring of water quality from a plurality of sampling positions in the energy plant in the nuclear heating project to ensure that the water quality from the plurality of sampling positions meets a corresponding water quality indicator, where the plurality of sampling positions includes a demineralized water inlet, a deaerator downpipe, a secondary water supply pump outlet, steam condensate, industrial steam and evaporator discharge; and in the event that the energy plant in the nuclear heating project is shut down, the maintenance of the plurality of devices and piping in the energy plant in the nuclear heating project.

[0005] In a specific implementation of this disclosure, in a case where the power plant in the nuclear heating project begins a flushing operation, the analysis and supervision of the flushing water quality in the plurality of devices and piping in the power plant of the nuclear heating project to ensure that the flushing water quality in the plurality of devices and piping in the power plant of the nuclear heating project meets the corresponding water quality indicators includes: during the start-up flushing of the power plant of the nuclear heating project, in a case where the device in the power plant of the nuclear heating project is a demineralized water tank, the supervision of the flushing water quality of the demineralized water tank to meet a first water quality indicator,where the first indicator of water quality includes a conductivity not exceeding 1.2 qs / cm, a pH range of 5.6-8.0, dissolved silicon not exceeding 20 qg / L, chloride ions not exceeding 50 qg / L, sulfates not exceeding 50 qg / L, and total organic carbon not exceeding 500 qg / L; in a case where the device in the nuclear heating project's power plant is a feedwater tank, the monitoring of the feedwater tank's flushing water quality to meet a second water quality indicator, where the second water quality indicator includes a conductivity before ammonia addition not exceeding 1.2 qs / cm, a conductivity range after ammonia addition between 4.1 qs / cm and 8.6 qs / cm, a pH range before ammonia addition between 5.6 and 8.0, and a pH range after ammonia addition between 9.0 and 9,6; in a case where the device in the nuclear heating project power plant is a device other than a demineralized water tank, a feedwater tank and an evaporator, the supervision of the quality of the flushing water of the device other than the demineralized water tank, the feedwater tank and the evaporator to meet a third water quality indicator, where the third water quality indicator includes chloride ions not exceeding 300 qg / L, iron ne, not exceeding 300 pg / L and a light transmission not less than 90%; in a case where the device in the nuclear heating project power plant is a degasser, the supervision of the quality of the degasser flush water before the water enters an evaporator and superheater system to meet a fourth water quality indicator, where the fourth water quality indicator includes a pH range between 9.5 and 10.0 and chloride ions not exceeding 50 pg / L; and in a case where the device in the nuclear heating project power plant is an evaporator, the supervision of the quality of the evaporator flush water to meet a fifth water quality indicator during initial loading, where the fifth water quality indicator includes chloride ions not exceeding 100 pg / L and a light transmission not less than 90%;and for the piping in the nuclear heating project power plant, the supervision of the quality of the piping flushing water in the nuclear heating project power plant to meet a sixth water quality indicator, where the sixth water quality indicator includes a light transmission not less than 90%, fluoride ions not exceeding 100 pg / L, chloride ions not exceeding 100 pg / L, sulfates not exceeding 100 pg / L and total organic carbon not exceeding 500 pg / L.;

[0006] In a specific implementation of this disclosure, in the case where the nuclear heating project power plant is operating normally, the analysis and supervision of the water quality of a plurality of sampling positions in the nuclear heating project power plant to ensure that the water quality of the plurality of sampling positions meets the corresponding water quality indicator includes: during the normal operation of the nuclear heating project power plant, in the case where the sampling position is a demineralized water inlet, the supervision of the water quality at the demineralized water inlet to meet a seventh water quality indicator, where the seventh water quality indicator includes a conductivity range of 4.1-8.6 ps / cm, and a pH range of 9.2-9.5;during normal operation of the nuclear heating project power plant, in the case where the sampling position is a degasser downpipe, the water quality monitoring at the degasser downpipe is to meet an eighth water quality indicator, where the eighth water quality indicator includes that dissolved oxygen is not greater than 50 pg / L, and a pH range of 9.2-9.5.

[0007] In a specific implementation of this disclosure, in the event that the nuclear heating project's power plant is operating normally, the analysis and monitoring of water quality from a plurality of locations Sampling in the nuclear heating project power plant to ensure that the water quality of the plurality of sampling positions meets the corresponding water quality indicator includes: in the case where the nuclear heating project power plant is operating normally, setting up an online cationic conductivity at sampling positions of a secondary pump outlet of water supply, steam condensate, industrial steam and evaporator discharge of the power plant, and monitoring the cationic conductivity of the water quality at a corresponding sampling position with the online cationic conductivity.

[0008] In a specific implementation of this disclosure, the frequency of monitoring parameters in water quality at the demineralized water inlet is once a month.

[0009] In a specific implementation of this disclosure, in a case where the nuclear heating project power plant is operating normally, the online cationic conductivity configuration at the sampling positions of the secondary feedwater pump outlet, steam condensate, industrial steam and the power plant evaporator discharge, and the monitoring of the water quality cationic conductivity at the corresponding sampling position with the online cationic conductivity includes: during the normal operation of the nuclear heating project power plant, in a case where the sampling position is the secondary feedwater pump outlet, the monitoring of the water quality at the secondary feedwater pump outlet to meet a ninth water quality indicator,where the ninth water quality indicator includes the fact that a cationic conductivity is not greater than 0.2 qs / cm, that dissolved oxygen is not greater than 50 qg / L, that a pH range is 9.2-9.5, that sodium is not greater than 3 qg / L, that dissolved silicon is not greater than 10 qg / L and that iron is not greater than 50 qg / L; During normal operation of the nuclear heating project's power plant, in a case where the sampling position is the steam condensate, the water quality at the steam condensate level is monitored to meet one-tenth of a water quality indicator, where the tenth water quality indicator includes the fact that a cationic conductivity is not greater than 0.2 qs / cm, that dissolved oxygen is not greater than 10 qg / L and that sodium is not greater than 5 qg / L; during normal operation of the nuclear heating project's power plant,in a case where the sampling position is industrial steam, water quality monitoring at the industrial steam level to meet an eleventh water quality indicator, where the eleventh water quality indicator includes the fact that a, cationic conductivity is not greater than 0.2 qs / cm; and during normal operation of the nuclear heating project power plant, in a case where the sampling position is the evaporator discharge, the water quality monitoring at the evaporator discharge level is to meet a twelfth water quality indicator, where the twelfth water quality indicator includes the fact that a cationic conductivity is not greater than 4 qs / cm and that chlorine is not greater than 100 qg / L.

[0010] In a specific implementation of this disclosure, a monitoring frequency of cationic conductivity in water quality at the evaporator discharge is once a month, and a monitoring frequency of chlorine in water quality at the evaporator discharge is once every two weeks.

[0011] In a specific implementation of this disclosure, in the event that the nuclear heating project power plant is shut down, the maintenance of the multiple devices and piping in the nuclear heating project power plant includes: determining if a shutdown time of the nuclear heating project power plant exceeds a predefined number of days; in the event that the shutdown time of the nuclear heating project power plant does not exceed the predefined number of days, loading the multiple devices and piping in the nuclear heating project power plant with a maintenance fluid having chloride ions < 50 qg / L; and in the event that the shutdown time of the nuclear heating project power plant exceeds the predefined number of days, draining for wet maintenance or dry maintenance.

[0012] In a specific implementation of this disclosure, in a case where the power plant outage time in the nuclear heating project exceeds the predefined number of days, drainage for dry or wet maintenance includes: in a case where the power plant outage time in the nuclear heating project exceeds the predefined number of days and drainage is adopted for dry maintenance, the removal of water from the multiple devices and drying or dehumidification with air, the loading of nitrogen at a pressure of 0.07 MPa after the internal parts of the multiple devices are dry, and the replenishment of nitrogen in a case where a nitrogen pressure is less than 0.02 MPa.

[0013] In a specific implementation of this disclosure, in a case where the power plant downtime in the nuclear heating project exceeds the predefined number of days, the drainage for dry or wet maintenance includes: in a case where the power plant downtime in the nuclear heating project exceeds the predefined number of days, carrying out wet maintenance in a manner not exceeding the predefined number of days during an overhaul period after the first purge of a steam line outside a plant is completed, and monitoring anion concentration in a primary device to meet a wet maintenance water quality indicator.

[0014] In a specific implementation of this disclosure, the main device includes an evaporator, and a wet maintenance water quality indicator corresponding to the evaporator includes that a hydrazine range is 20 mg / L to 100 mg / L, that a pH range is 9.5-10.0, that the fluoride ion is not greater than 100 pg / L, and that the chloride ion is not greater than 100 pg / L.

[0015] In a specific implementation of this disclosure, the main device further includes other devices besides the evaporator, and a wet maintenance water quality indicator corresponding to the other devices besides the evaporator includes that hydrazine is not less than 50 mg / L, that a pH range is 9.5-10.0, that fluoride ion is not more than 50 pg / L, and that chloride ion is not more than 50 pg / L.

[0016] The technical solution of this disclosure has the following beneficial effects. Targeting the first nuclear heating project in China, a method for monitoring water quality for a nuclear heating device is proposed. During the flushing phase at the start-up of a power plant in the nuclear heating project, the quality of the flushing water is analyzed and monitored. During the normal operation of a power plant in the nuclear heating project, specific sampling points are defined for the analysis and monitoring of water quality, thereby ensuring that the water quality of the power plant in the nuclear heating project is well monitored at different stages, effectively reducing corrosion and scaling of a thermal conversion device, and improving the safety and economics of the operation of the thermal conversion device.In addition, a plurality of devices and pipes in the power plant in the nuclear heating project are maintained during the shutdown of the power plant in the nuclear heating project, so that the devices and pipes can be well maintained during the shutdown period, and that the corrosion rate of the devices and pipes can be considerably reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] [Fig.1] is a schematic flowchart of a water quality monitoring process for a nuclear heating device according to a first embodiment of the present disclosure.

[0018] [Fig.2] is a schematic diagram of the corresponding sampling positions on a water supply system according to an embodiment of the present disclosure.

[0019] [Fig.3] is a schematic diagram of the corresponding sampling positions on an evaporator according to an embodiment of the present disclosure.

[0020] [Fig.4] is a schematic diagram of the corresponding sampling positions on a vapor condensate system according to an embodiment of the present disclosure.

[0021] [Fig.5] is a schematic flowchart of a water quality monitoring process for a nuclear heating device according to a second embodiment of the present disclosure.

[0022] [Fig.6] is a schematic flowchart of a water quality monitoring process for a nuclear heating device according to a third embodiment of the present disclosure.

[0023] [Fig.7] is a schematic flowchart of a water quality monitoring process for a nuclear heating device according to a fourth embodiment of this disclosure.

[0024] [Fig.8] is a schematic flowchart of a water quality monitoring method for a nuclear heating device according to a fifth embodiment of this disclosure.

[0025] [Fig.9] is a schematic flowchart of a water quality monitoring method for a nuclear heating device according to a sixth embodiment of this disclosure. DETAILED DESCRIPTION OF THE IMPLEMENTATION METHODS

[0026] The technical solutions of the embodiments of this disclosure are clearly and fully described below with reference to the accompanying figures of the embodiments of this disclosure. It appears that the described embodiments represent only a part, rather than all, of the embodiments of this disclosure. All other embodiments derived by persons skilled in the art based on the embodiments of this disclosure without creative effort shall fall within the scope of protection of this disclosure.

[0027] At least one embodiment of this disclosure provides a method for monitoring water quality for a nuclear heating device, and with reference to [Fig.1], the method for monitoring water quality for the nuclear heating device includes the following steps.

[0028] SI: In the event that a power plant of a nuclear heating project initiates a flushing operation, the quality of the flushing water in a plurality of devices and piping in the power plant of the nuclear heating project is analyzed and monitored to ensure that the flushing water quality in the plurality of devices and piping in the power plant of the nuclear heating project meets a corresponding water quality indicator. The plurality of devices includes a demineralized water tank, a feedwater tank, a primary preheater, a deaerator, an evaporator, and a superheater.

[0029] For example, when a power plant in a nuclear heating project is started up, a plurality of devices and pipelines in the power plant are chemically flushed to achieve a certain flushing water quality. By analyzing and monitoring the flushing water quality, if the flushing water quality in certain devices or pipelines in the power plant does not meet a corresponding water quality indicator, a flush may be carried out on certain devices or pipelines several times, or a flushing agent may be replaced, until the corresponding water quality indicator is met.

[0030] It should be noted that the purpose of the chemical flushing is to remove impurities from the plurality of devices and piping in the nuclear heating project's power plant. Impurities include, but are not limited to, particulate impurities, rusty sludge, corrosive impurities, etc. The demineralized water tank, the feedwater tank, and the primary preheater are devices in the power plant's feedwater system. The evaporator and superheater are devices in a heat conversion unit. Piping in the nuclear heating project's power plant includes, but is not limited to, steam condensate piping and other piping.The flushing at start-up of the nuclear heating project power plant includes, but is not limited to, a cold test, a hot test and purging of the power plant steam lines.

[0031] In certain embodiments, after step SI, the process further comprises: replacing the clean water in the plurality of devices and pipes with demineralized water containing ammonia, and then completing the start-up flush. In this way, the clean water in the plurality of devices and pipes is replaced with demineralized water containing ammonia, and a working fluid meeting a requirement is supplied during the start-up of the power plant in the nuclear heating project before normal operation.

[0032] S2: In a case where the power plant in the nuclear heating project is operating normally, the water quality of a plurality of positions Sampling at the power plant in the nuclear heating project is analyzed and monitored to ensure that the water quality at the plurality of sampling points meets a corresponding water quality indicator. The plurality of sampling points includes a demineralized water inlet, a deaerator downpipe, a secondary water supply pump outlet, a steam condensate outlet, an industrial steam outlet, and an evaporator discharge.

[0033] For example, the sampling positions corresponding to the demineralized water inlet, the deaerator downpipe, and the secondary feed pump outlet can be the positions shown in [Fig. 2]. The sampling position corresponding to the secondary feed pump outlet can also be called the secondary feed pump outlet sampling point. The evaporators include an A-row evaporator, a B-row evaporator, a C-row evaporator, and a D-row evaporator, and the sampling positions for the industrial steam and the evaporator discharge can be the positions shown in [Fig. 3]. The sampling position for the steam condensate can also be called the condensate sampling point, which can specifically be the position shown in [Fig. 4].

[0034] S3: The plurality of devices and piping in the power plant in the nuclear heating project are maintained in a case where the power plant in the nuclear heating project is shut down.

[0035] It should be noted that, during the debugging of the project, a water quality supervision procedure can be written, a technical document is formed, and water quality can be supervised according to the document.

[0036] According to the technical solution provided by the embodiment of this disclosure, a method for monitoring water quality for a nuclear heating device is provided for the first nuclear heating project in China. The quality of the flushing water is analyzed and monitored during the start-up flushing of the power plant in the nuclear heating project, and specific sampling positions are defined during the normal operation of the power plant in the nuclear heating project for the analysis and monitoring of water quality, so that the water quality of the power plant in the nuclear heating project is well monitored at different stages, that corrosion and scaling of a thermal conversion device are effectively reduced, and that the operational safety and economy of the thermal conversion device are improved.In addition, a plurality of devices and piping in the power plant in the nuclear heating project are maintained during the power plant shutdown in the nuclear heating project, so that the devices and piping can be properly maintained during the period. of shutdown, and that the corrosion rate of devices and pipelines can be considerably reduced.

[0037] In at least one embodiment of this disclosure, with reference to [Fig.5], any one or more of S 1.1 to S 1.6 is a specific implementation of the IS.

[0038] S 1.1: During the start-up flushing of the power plant in the nuclear heating project, in a case where the device in the power plant in the nuclear heating project is a demineralized water tank, the quality of the flushing water from the demineralized water tank is monitored to meet a first water quality indicator. The first water quality indicator includes a conductivity not exceeding 1.2 qs / cm, a pH range of 5.6 to 8.0, dissolved silicon not exceeding 20 qg / L, chloride ions not exceeding 50 qg / L, sulfates not exceeding 50 qg / L, and total organic carbon not exceeding 500 qg / L.

[0039] More specifically, the first water quality indicator is specifically mentioned in Table 1 below. [Tables 1] Monitoring element Monitoring unit Qualified indicator Note Conductivity qs / cm <1.2 pH / 5.6-8.0 Dissolved silica qg / L <20 Chloride ion qg / L <50 Sulfate qg / L <50 TOC qg / L <500

[0040] Table 1. First water quality indicator for the quality of the rinse water from the demineralized water tank.

[0041] S 1.2: In the case where the device in the power plant of the nuclear heating project is a feedwater tank, the quality of the feedwater tank flushing water is monitored to meet a second water quality indicator. The second water quality indicator includes the fact that a conductivity before the addition of ammonia does not exceed 1.2 qs / cm, a conductivity range after the addition of ammonia is from 4.1 qs / cm to 8.6 qs / cm, a pH range before the addition of ammonia is from 5.6 to 8.0, and a pH range after the addition of ammonia is from 9.0 to 9.6.

[0042] More specifically, the second water quality indicator is specifically mentioned in Table 2 below. [Tables 2] Monitoring element Monitoring unit Qualified indicator / after ammonia addition Note Conductivity qs / cm <1.2 / 4.1-8.6 / pH / 5.6-8.0 / 9.0-9.6 /

[0043] Table 2. Second water quality indicator for the quality of the rinse water from the water supply tank.

[0044] S 1.3: In a case where the apparatus in the power plant in the nuclear heating project is an apparatus other than a demineralized water tank, a feedwater tank, and an evaporator, the quality of the flushing water from the apparatus other than the demineralized water tank, the feedwater tank, and the evaporator is monitored to meet a third water quality indicator. The third water quality indicator includes ensuring that chloride ions do not exceed 300 qg / L, iron does not exceed 300 qg / L, and light transmission is not less than 90%.

[0045] More specifically, the third water quality indicator is specifically mentioned in Table 3 below. [Tables 3] Monitoring element launched Monitoring unit Qualified indicator Note Chloride ion qg / L <300 / Iron qg / L <300 / Light transmission % >90 /

[0046] Table 3: Third indicator of the quality of the rinse water of the device, excluding the demineralized water tank, the water supply tank and the evaporator.

[0047] S 1.4: In a case where the device in the power plant of the heating project In a nuclear degasser, the quality of the degasser rinsing water before it enters the evaporator and superheater system is monitored to meet a fourth water quality indicator. This fourth indicator requires a pH range of 9.5–10.0 and that chloride ions do not exceed 50 qg / L.

[0048] More specifically, the fourth water quality indicator is specifically mentioned in Table 4 below. In some variants, the pH of the rinse water can be adjusted to meet standards by adding ammonia water. [Tables 4] Monitoring element, monitoring unit, qualified indicator, pH rating / 9.5-10.0 / Chloride ion qg / L <50 / Ammonia qg / L / 2

[0049] Table 4. Fourth water quality indicator for the quality of the deaerator rinse water before the water enters the evaporator and superheater system.

[0050] It should be noted that, in all tables, the "2" in the notes means that the pH meets the standards after the addition of ammonia.

[0051] S 1.5: In a case where the apparatus in the nuclear heating project's power plant is an evaporator, the quality of the evaporator flushing water is monitored to meet a fifth water quality indicator during initial loading. The fifth water quality indicator includes ensuring that the chloride ion does not exceed 100 qg / L, and that the light transmission is not less than 90%.

[0052] More specifically, the fifth water quality indicator is specifically mentioned in Table 5 below. In some variations, a water quality indicator on the cold tube side of the evaporator may refer to a water quality indicator on the shell side. [Tables 5] Monitoring element launched Monitoring unit Qualified indicator Note Chloride ion qg / L <100 / Light transmission % >90 /

[0053] Table 5: Fifth rinse water quality indicator for evaporator rinse water quality.

[0054] S 1.6: For the piping in the nuclear heating project's power plant, the quality of the piping flushing water in the power plant of the nuclear heating project is monitored to meet a sixth water quality indicator. The sixth water quality indicator includes that light transmission is not less than 90%, fluoride ions do not exceed 100 qg / L, the chloride ions do not exceed 100 qg / L, sulfates do not exceed 100 qg / L, and total organic carbon does not exceed 500 qg / L. [Tableauxô] Monitoring element launched Monitoring unit Qualified indicator Rating Light transmission % >90 / Fluoride ion qg / L <100 / Chloride ion qg / L <100 / Sulfate qg / L <100 / TOC qg / L <500 /

[0055] Table 6: Sixth water quality indicator for the quality of pipe flushing water.

[0056] In the embodiments of this disclosure, when the power plant in the nuclear heating project begins a flushing, the water quality indicators of the flushing water quality of the plurality of devices and pipelines in the power plant in the nuclear heating project are standardized, and the water quality supervision in the start-up flushing stage focuses mainly on light transmission, iron, anions (chloride ions, sulfate ions) and other elements, and the water quality indicators of the flushing water quality of the plurality of devices and pipelines are arranged in a differentiated manner.That is to say, water quality monitoring focuses more on the chloride ion indicator at the evaporator, and water quality monitoring focuses on the iron flushing effect of other upstream devices, so that the devices and piping are ensured to be properly flushed before the power plant starts up, the devices and piping are ensured to be in a clean condition before the power plant starts up, and that the power plant is started up safely.

[0057] In at least one embodiment of this disclosure, with reference to [Fig.6], S2.3 is a specific implementation of S2.

[0058] S2.3: In a case where the power plant in the nuclear heating project When functioning normally, an online cationic conductivity is set at the sampling positions of a secondary pump outlet of water supply, steam condensate, industrial steam and evaporator discharge of the power plant, and the cationic conductivity of the water quality is monitored at a sampling position corresponding with the online cationic conductivity.

[0059] In the embodiment of this disclosure, the cationic conductivity indicator is enhanced by monitoring water quality at multiple sampling points, such as the secondary water supply pump outlet, steam condensate, industrial steam, and the power plant evaporator discharge, in order to mitigate the influence of ammonia in a water sample from the ammonia system on conductivity. Furthermore, monitoring efficiency can be improved by adding online cationic conductivity monitoring at the relevant sampling points.

[0060] In at least one embodiment of this disclosure, with reference to [Fig.6], S2 further comprises S2.1 and S2.2.

[0061] S2.1: During normal operation of the power plant in the project of In nuclear heating systems, if the sampling point is a demineralized water inlet, the water quality at the inlet is monitored to meet a seventh water quality indicator. This seventh indicator includes a conductivity range of 4.1 to 8.6 µS / cm and a pH range of 9.2 to 9.5.

[0062] S2.2: During the normal operation of the power plant in the project In nuclear heating systems, where the sampling point is a degasser downpipe, the water quality at the downpipe is monitored to meet an eighth water quality indicator. This eighth indicator includes a dissolved oxygen content not exceeding 50 qg / L and a pH range of 9.2 to 9.5.

[0063] In at least one embodiment of this disclosure, the frequency of monitoring parameters in water quality at the demineralized water inlet is once a month.

[0064] In at least one embodiment of this disclosure, with reference to [Fig.7], S2.3.1 to S2.3.4 constitute a specific implementation of S2.3.

[0065] S2.3.1: During normal operation of the power plant in the In a nuclear heating project, where the sampling point is the outlet of the secondary water supply pump, the water quality at the outlet of the secondary water supply pump is monitored to meet a ninth water quality indicator. This ninth water quality indicator includes a cationic conductivity not exceeding 0.2 qs / cm, a dissolved oxygen content not exceeding 50 qg / L, a pH range of 9.2 to 9.5, a sodium content not exceeding 3 qg / L, a dissolved silicon content not exceeding 10 qg / L, and an iron content not exceeding 50 qg / L.

[0066] S2.3.2: During normal operation of the power plant within the framework of the nuclear heating project, in the case where the sampling position is the Steam condensate, the water quality of the steam condensate is monitored to meet a tenth water quality indicator. The tenth water quality indicator includes ensuring that cationic conductivity does not exceed 0.2 qs / cm, dissolved oxygen does not exceed 10 qg / L, and sodium does not exceed 5 qg / L.

[0067] S2.3.3: During normal operation of the power plant within the framework In the nuclear heating project, where the sampling point is industrial steam, the water quality of the industrial steam is monitored to meet an eleventh water quality indicator. This eleventh water quality indicator includes the requirement that the cationic conductivity does not exceed 0.2 qs / cm.

[0068] S2.3.4: During normal operation of the power plant within the framework In the nuclear heating project, where the sampling location is the evaporator discharge, the water quality of the evaporator discharge is monitored to meet a twelfth water quality indicator. This twelfth indicator includes ensuring that the cationic conductivity does not exceed 4 qs / cm and that the chlorine level does not exceed 100 qg / L.

[0069] In at least one embodiment of this disclosure, the frequency of monitoring the cationic conductivity of the water quality at the evaporator discharge is once a month, and the frequency of monitoring chlorine in the water quality at the evaporator discharge is once every two weeks.

[0070] The water quality indicators for water at the different sampling positions during the normal operation of the power plant within the framework of the nuclear heating project are presented in Table 7 below. [Tables 7] Number Sampling Position Parameter Unit Limit Value Measurement Frequency 1 Demineralized Water Inlet (QUG01) Conductivity* qs / cm 4.1-8.6 Once a month 2 pH* / 9.2-9.5 3 Deaerator Downpipe (QUG02) Dissolved Oxygen* qg / L <50 Once a month 4 pH* / 9.2-9.5 5 Secondary Water Supply Pump Outlet (QUG03) Cationic Conductivity* qs / cm <0.2 Once a month 6 Dissolved Oxygen* qg / L <50 7 pH* / 9.2-9.5 8 Sodium* qg / L <3 9 Dissolved Silica* qg / L <10 10 Iron qg / L <50 11 Vapor Condensate (QUG04) Cationic Conductivity* qs / cm <0.2 Once a month 12 Dissolved oxygen * qg / L <10 13 Sodium* qg / L <5 14 Industrial steam (QUG05) Cationic conductivity* qs / cm <0.2 Once a month 15 Evaporator discharge (QUG06) Cationic conductivity* qs / cm <4 Once a month 16 Chlorine qg / L <100 Once every two weeks

[0071] Table 7: Water quality indicators at the plurality of sampling positions during normal operation of the power plant in the nuclear heating project.

[0072] It should be noted that the above water quality indicators are measured at a temperature of 25 °C, unless otherwise specified. * represents continuous online monitoring. The industrial steam loop uses evaporative treatment. Total ammonia is added to the feed water to control the pH value, and the pH value of the demineralized water is adjusted to 9.2–9.5. The power plant's thermal control room can adjust the amount of ammonia added to the demineralized water in real time via the demineralized water's online pH meter. Deoxygenation on the industrial water feed side is achieved through the physical deoxygenation function of the degasser. Without the addition of hydrazine for chemical deoxygenation, the dissolved oxygen in the feed water at the degasser outlet is guaranteed to be <50 qg / L. The steam condensate is heated and returned to the unit's condenser for recovery, and online cation conductivity meters, oximeters, and sodium meters are configured to monitor the water quality in real time at the corresponding sampling points.

[0073] In the embodiments of this disclosure, the corresponding water quality indicators are defined at different sampling positions in the case where the power plant in the nuclear heating project is operating normally, so that the devices and piping are in a clean state in the case where the power plant in the nuclear heating project is operating normally, that corrosion and scaling of the thermal conversion device are further effectively reduced, and that the safety and operating economy of the thermal conversion device are improved.

[0074] In at least one embodiment of this disclosure, with reference to [Fig.8], S3.1 to S3.3 is a specific implementation of S3.

[0075] S3.1: It is judged whether a shutdown of the power plant in the project of Nuclear heating exceeds a predetermined number of days.

[0076] S3.2: In a case where the downtime of the power plant in the project of nuclear heating does not exceed the predetermined number of days, the plurality of devices and pipes in the power plant in the nuclear heating project are charged with a maintenance liquid with chloride ions < 50 qg / L.

[0077] S3.3: In a case where the downtime of the power plant in the project of If nuclear heating exceeds the predetermined number of days, a draining is carried out for dry maintenance or wet maintenance.

[0078] It should be noted that the predetermined number of days can be defined according to an actual requirement. For example, in some embodiments, the predetermined number of days can range from 10 days to 20 days, for example 15 days.

[0079] In the embodiments of this disclosure, an appropriate maintenance method is selected based on the power plant shutdown time in the nuclear heating project, and wet maintenance or dry maintenance may be adopted as appropriate, so that the devices can be properly maintained during the shutdown period.

[0080] In at least one embodiment of this disclosure, with reference to [Fig.9], S3.3.1 and S3.3.2 are a specific implementation of S3.3.

[0081] S3.3.1: In a case where the downtime of the power plant in the project of nuclear heating exceeds the predetermined number of days and where drainage is adopted for dry maintenance, water from the plurality of devices is drained, air drying or dehumidification is carried out, nitrogen is charged to a pressure of 0.07 MPa after the internal parts of the plurality of devices are dry, and nitrogen is topped up in a case where nitrogen pressure is less than 0.02 MPa.

[0082] Therefore, dry maintenance is adopted after the hot test is stopped by dismantling the power plant, nitrogen is charged in a timely manner after the water from the devices has been drained, the water vapor is replaced by the residual temperature of the devices, the dew point of the gas in the devices is monitored, and dry maintenance is ensured to meet a requirement.

[0083] S3.3.2: In a case where the downtime of the power plant in the project of nuclear heating exceeds the predetermined number of days, wet maintenance is carried out in a manner not exceeding the predetermined number of days during a maintenance period after the first flush of a steam pipeline outside a plant is completed, and anion concentration in a main device is monitored to meet a wet maintenance water quality indicator.

[0084] In some embodiments, the main device includes an evaporator, and a wet maintenance water quality indicator corresponding to the evaporator includes that a hydrazine range is between 20 mg / L and 100 mg / L, that a pH range is between 9.5 and 10.0, that fluoride ions do not exceed 100 qg / L and that chloride ions do not exceed 100 qg / L.

[0085] The wet maintenance water quality indicator of the evaporator is detailed in Table 8 below. [Tables 8] Monitoring element launched Monitoring unit Qualified indicator Note Hydrazine mg / L 20-100 / pH / 9.5-10.0 / Fluoride ion qg / L <100 / Chloride ion qg / L <100 /

[0086] Table 8: Evaporator wet maintenance water quality indicator.

[0087] In at least one embodiment of this disclosure, the main device further includes other devices besides the evaporator, and a wet maintenance water quality indicator corresponding to the other devices besides the evaporator includes the fact that the hydrazine is not less than 50 mg / L, a pH range is 9.5-10.0, the fluoride ion is not more than 50 pg / L, and the chloride ion is not more than 50 pg / L.

[0088] The wet maintenance water quality indicators of the other devices, with the exception of the evaporator, are detailed in Table 9 below. [Tables 9] Monitoring element Monitoring unit Qualified indicator Note Hydrazine mg / L >50 / pH / 9.5-10.0 / Ammonia mg / L 0-400 As long as the ammonia concentration meets the pH requirement Fluoride ion qg / L <50 / Chloride ion qg / L <50 /

[0089] Table 9: Indicators of wet maintenance water quality of other devices, excluding the evaporator.

[0090] It should be noted that the combination of technical features in the embodiments of this disclosure is not limited to the combination described in the embodiments of this disclosure or to the combination described in the specific embodiments. All the technical features described in this disclosure may be freely combined or arranged in any way, unless they are contradictory.

[0091] As this disclosure and the claims show, unless the context clearly indicates otherwise, the words "a," "an," and / or "the" are not intended to denote the singular but may include the plural. In general, the terms "include" and "comprise" indicate only the inclusion of the explicitly identified steps and elements, and these steps and elements do not constitute an exhaustive list; the method or device may also include other steps or elements.

[0092] The terms "first" and "second" are for descriptive purposes only and shall not be construed as indicating or implying relative importance or an implicit indication of the number of technical features indicated. By Therefore, a feature limited by "first", "second", etc., may explicitly or implicitly indicate one or more of these features.

[0093] The foregoing descriptions are merely preferred embodiments of this disclosure, but are not intended to limit this disclosure. Any modification, equivalent substitution, or other action, made without departing from the spirit and principle of this disclosure, remains within the scope of protection of this disclosure.

Claims

Demands

1. A method for monitoring water quality for a nuclear heating device, comprising: in a case where a power plant in a nuclear heating project begins a flushing, the analysis and monitoring of the quality of the flushing water in a plurality of devices and piping in the power plant of the nuclear heating project to ensure that the quality of the flushing water in the plurality of devices and piping in the power plant of the nuclear heating project meets a corresponding water quality indicator, where the plurality of devices includes a demineralized water tank, a feedwater tank, a primary preheater, a deaerator, an evaporator and a superheater;in a case where the nuclear heating project power plant is operating normally, the analysis and monitoring of water quality at a plurality of sampling positions in the nuclear heating project power plant to ensure that the water quality at the plurality of sampling positions meets a corresponding water quality indicator, where the plurality of sampling positions includes a demineralized water inlet, a deaerator downpipe, a secondary feedwater pump outlet, steam condensate, industrial steam and an evaporator discharge; and in a case where the nuclear heating project power plant is shut down, the maintenance of the plurality of devices and piping in the nuclear heating project power plant.

2. The method for monitoring water quality for the nuclear heating device according to claim 1, wherein, in a case where the plant in the nuclear heating project begins flushing, the analysis and monitoring of the flushing water quality in the plurality of devices and pipelines in the plant of the nuclear heating project to ensure that the flushing water quality in the plurality of devices and pipelines in the plant of the nuclear heating project meets the corresponding water quality indicators comprises: during a start-up flush of the nuclear heating project plant, in a case where the device in the nuclear heating project plant is the demineralized water tank, monitoring of the quality of the flush water from the demineralized water tank to meet a first water quality indicator, in which the first water quality indicator includes a conductivity not exceeding 1.2 p,s / cm, a pH range of 5.6-8.0, dissolved silicon not exceeding 20 p,g / L, chloride ions not exceeding 50 p,g / L, sulfates not exceeding 50 lg / L, and total organic carbon not exceeding 500 p,g / L; in a case where the device in the nuclear heating project power plant is the feedwater tank, monitoring of the quality of the feedwater tank flushing water to meet a second water quality indicator, in which the second water quality indicator includes a conductivity before ammonia addition not exceeding 1.2 p,s / cm, a conductivity range after ammonia addition of 4.1 iis / cm-8.6 us / cm, a pH range before ammonia addition of 5.6-8.0, and a pH range after ammonia addition of 9.0-9.6; in a case where the device in the nuclear heating project power plant is a device other than the demineralized water tank, the water supply tank and the evaporator, monitoring of the quality of the flushing water of the device other than the demineralized water tank, the water supply tank and the evaporator to meet a third water quality indicator, in which the third water quality indicator includes chloride ions not exceeding 300 p,g / L, iron not exceeding 300 itg / L, and a light transmission not less than 90%; in a case where the device in the nuclear heating project power plant is the degasser, monitoring of the quality of the degasser flushing water before the water enters an evaporator and superheater system to meet a fourth water quality indicator, in which the fourth water quality indicator includes a pH range of 9.5-10.0 and chloride ions not exceeding 50 p,g / L; in a case where the device in the nuclear heating project plant is the evaporator, monitoring the quality of the evaporator flushing water to meet a fifth indicator of water quality at initial loading, wherein the fifth water quality indicator includes chloride ions not exceeding 100 qg / L and a light transmission not less than 90%; and for the piping in the nuclear heating project plant, monitoring the quality of the piping flushing water in the nuclear heating project plant to meet a sixth water quality indicator, wherein the sixth water quality indicator includes a light transmission not less than 90%, fluoride ions not exceeding 100 qg / L, chloride ions not exceeding 100 qg / L, sulfates not exceeding 100 qg / L, and total organic carbon not exceeding 500 qg / L.

3. The water quality monitoring method for the nuclear heating device according to claim 1, wherein in a case where the nuclear heating plant is operating normally, the analysis and monitoring of the water quality of the multiple sampling positions in the nuclear heating plant to ensure that the water quality of the multiple sampling positions meets the corresponding water quality indicators include: during normal operation of the nuclear heating plant, in a case where the sampling position is the demineralized water inlet, the monitoring of the water quality at the demineralized water inlet to meet a seventh water quality indicator, wherein the seventh water quality indicator includes a conductivity range of 4.1-8.6 qs / cm, and a pH range of 9.2-9.5;and during the normal operation of the nuclear heating plant, in a case where the sampling position is the degasser downpipe, monitoring the water quality at the degasser downpipe to meet an eighth water quality indicator, in which the eighth water quality indicator includes a dissolved oxygen content not exceeding 50 qg / L, and a pH range of 9.2-9.

5.

4. The method for monitoring water quality for the nuclear heating device according to claim 1, wherein, in a case where the nuclear heating project power plant

5. functions normally, the analysis and supervision of water quality at multiple sampling positions in the nuclear heating project power plant to ensure that the water quality at multiple sampling positions meets the corresponding water quality indicators include: in a case where the nuclear heating project power plant is functioning normally, configure an online cationic conductivity at the sampling positions of the secondary feed water pump outlet, steam condensate, industrial steam and evaporator discharge of the power plant, and monitor the cationic conductivity of the water quality at a corresponding sampling position with the online cationic conductivity. The water quality monitoring method for the nuclear heating device according to claim 4, wherein, in a case where the nuclear heating project power plant is operating normally, the online cationic conductivity configuration at the sampling positions of the secondary pump outlet of the water supply, steam condensate, industrial steam and evaporator discharge of the power plant, and the monitoring of the cationic conductivity of the water quality at the corresponding sampling position with the online cationic conductivity comprises: during normal operation of the power plant in the nuclear heating project, in a case where the sampling position is the secondary feed water pump outlet, the monitoring of water quality at the secondary feed water pump outlet to meet a ninth water quality indicator, in which the ninth water quality indicator includes the fact that a cationic conductivity is not greater than 0.2 ps / cm, that dissolved oxygen is not greater than 50 pg / L, that a pH range is 9.2-9.5, that sodium is not greater than 3 pg / L, that dissolved silicon is not greater than 10 pg / L and that iron is not greater than 50 pg / L; During normal operation of the power plant in the nuclear heating project, in a case where the sampling position is the steam condensate, the water quality monitoring at the steam condensate must meet one-tenthwater quality indicator, in which the tenth water quality indicator includes the fact that a cationic conductivity is not greater than 0.2 ps / cm, that dissolved oxygen is not greater than 10 pg / L and that sodium is not greater than 5 pg / L; during normal operation of the power plant in the nuclear heating project, in a case where the sampling position is industrial steam, monitor the water quality of the industrial steam to meet an eleventh water quality indicator, the eleventh water quality indicator including the fact that a cationic conductivity is not greater than 0.2 ps / cm;and during normal operation of the power plant in the nuclear heating project, in a case where the sampling position is the evaporator blowdown, monitor the quality of the evaporator blowdown water to meet a twelfth water quality indicator, the twelfth water quality indicator including that a cationic conductivity is not greater than 4 ps / cm, and that chlorine is not greater than 100 pg / L.;

6. The method for monitoring water quality for the nuclear heating device according to any one of claims 1 to 5, wherein, in the event that the power plant in the nuclear heating project is shut down, maintaining the multiple devices and piping in the power plant in the nuclear heating project comprises: determining whether a shutdown period of the power plant in the nuclear heating project exceeds a predetermined number of days; in the event that the shutdown period of the power plant in the nuclear heating project does not exceed the predetermined number of days, charging the multiple devices and piping in the power plant in the nuclear heating project with a maintenance fluid having chloride ions < 50 pg / L;and in a case where the shutdown time of the power plant in the nuclear heating project exceeds the predefined number of days, drain for dry or wet maintenance.

7. The method for monitoring water quality for the nuclear heating device according to claim 6, wherein, in a case where the power plant downtime in the project of If nuclear heating exceeds the predetermined number of days, drainage for dry or wet maintenance includes: in a case where the power plant outage time in the nuclear heating project exceeds the predetermined number of days and drainage is adopted for dry maintenance, the removal of water from multiple devices and dry blowing or dehumidification with air, nitrogen charging at a pressure of 0.07 MPa after the internal parts of the multiple devices are dry, and nitrogen replenishment in a case where nitrogen pressure is less than 0.02 MPa.

8. The method of monitoring water quality for the nuclear heating device according to claim 6, wherein, in a case where the power plant outage time in the nuclear heating project exceeds the preselected number of days, the drainage for dry or wet maintenance comprises: in a case where the power plant outage time in the nuclear heating project exceeds the preselected number of days, carrying out wet maintenance in a manner not exceeding the preselected number of days during an overhaul period after completion of the first-stage flushing of a steam line outside a plant, and monitoring an anion concentration in a main device to meet a wet maintenance water quality indicator.

9. The water quality monitoring method for the nuclear heating device according to claim 8, wherein the main device comprises the evaporator, and a wet maintenance water quality indicator corresponding to the evaporator comprises a hydrazine range of 20 mg / L to 100 mg / L, a pH range of 9.5-10.0, fluoride ions not exceeding 100 pg / L, and chloride ions not exceeding 100 pg / L.

10. The method for monitoring water quality for the nuclear heating device according to claim 8, wherein the main device comprises other devices other than the evaporator, and the wet maintenance water quality indicator corresponding to the other devices other than the evaporator comprises that the hydrazine level is not less than 50 mg / L, a range pH of 9.5-10.0, fluoride ions not exceeding 50 pg / L, and chloride ions not exceeding 50 pg / L.

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