JP5705600B2 - Main steam moisture measuring device, main steam moisture measuring method and nuclear power plant - Google Patents

Description

  The present invention relates to a main steam moisture measuring device, a main steam moisture measuring method, and a nuclear power plant for measuring moisture in main steam of a nuclear power plant.

  Steam turbines constituting a nuclear power plant include a high-pressure turbine using steam generated by a steam generator in a nuclear reactor and a low-pressure turbine using steam once used in the high-pressure turbine. In order to improve the efficiency of the steam turbine and maintain the quality of the steam turbine, it is desirable to send steam with as little moisture as possible to the steam turbine. For example, when steam containing a predetermined amount or more of moisture is sent to the steam turbine, the durability of the rotor of the steam turbine may be reduced.

  In Patent Document 1, in order to manage the moisture in the steam sent to the steam turbine to a low value, the moisture near the inlet of the steam turbine or the outlet of the steam generator is measured using a calorimeter. A moisture measurement method is described. This moisture measuring method is a method of measuring the temperature of superheated steam obtained by adiabatic expansion of the steam flowing through the main steam pipe and calculating the moisture content in the steam from the enthalpy of the steam obtained.

  In Patent Document 2, the influence of N-13 on the radiation monitor that monitors the exhaust gas of the gas waste treatment system extracted from the water vapor flowing in the main steam pipe is reduced, and the sensitivity of the radiation monitor to the radioactive noble gas is increased. In addition, a fuel breakage detection apparatus and a detection method thereof that can increase the detection sensitivity of radioactive noble gas generated by fuel breakage are described. In this fuel damage detection method, non-radioactive argon gas is introduced into a nuclear reactor as a tracer gas, and activated Ar-41 is detected by an exhaust gas radiation monitor to monitor nuclear fuel damage in the nuclear reactor. is there.

Japanese Utility Model Publication No. 61-45469 Japanese Patent No. 3592474

  The value of moisture in the steam sent to the steam turbine is preferably 0.1% or less, more preferably 0.03% or less. However, the moisture measurement method based on the calorimeter method of Patent Document 1 causes a measurement error of about ± 0.1%. In the measurement of moisture in steam, this measurement error is large, and there is a problem that it is difficult to perform accurate moisture measurement by the calorimeter method. In addition, the calorimeter method has a problem that work safety is poor because it involves work near high-temperature and high-pressure piping.

  Further, the exhaust gas radiation monitor installed in the gas waste treatment system is a radioactive noble gas generated from nuclear fuel and an N-13 activation gas generated by activating oxygen atoms, which are the main components of water, in the reactor. , And the total amount of γ-rays from Ar-41 and the like generated by non-radioactive argon gas contained in in-leakage air being activated in the nuclear reactor. However, the method using the non-radioactive argon gas of Patent Document 2 as a tracer gas has a problem that the apparatus becomes complicated in order to correct the influence of N-13 and Ar-41 caused by other than nuclear fission.

  The present invention has been made in view of the above, and provides a main steam moisture measuring device, a main steam moisture measuring method, and a nuclear power plant that can accurately measure the moisture in the main steam. Is an issue.

  In order to solve the above-described problems and achieve the object, the main steam moisture measuring device of the present invention is a main steam moisture measuring device for measuring moisture in the main steam, and is used for secondary cooling of a water supply line. A chemical injection unit for adding a tracer element to water, a first vapor flow measurement unit for measuring the flow rate of steam introduced into a device disposed between the steam generator and the moisture separator and heater, Included in the drain water of the device, the second steam flow measuring unit that measures the flow rate of the steam introduced into the drain, the first measuring unit that measures the tracer element concentration contained in the blow-down water of the steam generator The second measuring unit for measuring the tracer element concentration, the steam flow rate acquired by the first steam flow rate measuring unit and the second steam flow rate measuring unit, and the first measuring unit and the second measuring unit are acquired. Tracer element concentration, and the moisture contained in the main steam Characterized in that it and a moisture calculation unit for calculating a.

  According to this configuration, a trace amount of tracer element is added to the secondary cooling water of the main water supply line, and the concentration of the tracer element contained in the SG blowdown (SGBD) water and the drain water of the equipment installed in the main steam line. Further, the flow rate of the steam introduced into the equipment installed in the main steam line can be measured, and the moisture content in the main steam can be calculated from the obtained tracer element concentration and the steam flow rate.

  The tracer element of the main vapor moisture measuring device of the present invention is preferably lithium (Li).

  According to this configuration, moisture in the main steam can be accurately measured by using a trace amount of lithium (Li) element for the tracer.

  The chemical injection part of the main steam moisture measuring device of the present invention is installed in the water supply line between the condensate demineralizer and the steam generator, and the tracer element can be added to the secondary cooling water flowing therethrough. ,preferable.

  According to this structure, a tracer element can be added to the secondary cooling water of the main water supply line using the existing chemical injection device. Thereby, it is not necessary to install an apparatus for newly adding a tracer element.

  It is preferable that the drain of the apparatus of the main steam moisture measuring device of the present invention is the high pressure drain of the high pressure turbine, the MS drain of the moisture separator, and the MSH heated steam drain of the moisture separator heater.

  According to this configuration, it is possible to accurately measure the moisture in the main steam by using a trace amount of lithium (Li) element for the tracer. Thereby, the tracer element concentration can be measured with the addition amount of lithium (Li) at a very low concentration that does not adversely affect the nuclear power plant equipment.

（上記式（１）中、Ｍは湿分（％）を表し、Ｃ_ＭＳ−ｄはＭＳドレン水、高圧ドレン水、ＭＳＨ加熱蒸気ドレン水の何れか一つに含まれるリチウム（Ｌｉ）濃度を表し、Ｑ_ＭＳ−ｄは上記Ｃ_ＭＳ−ｄに対応する何れか一つのドレンに導入された蒸気の流量を表し、Ｃ_ＳＧはＳＧブローダウン水に含まれるリチウム（Ｌｉ）濃度を表し、Ｑ_{ＭＳＲ−ｉｎ}は上記Ｃ_ＭＳ−ｄに対応する機器に導入された蒸気の流量を表す。） It is preferable that the moisture calculation part of the main steam moisture measuring device of the present invention calculates the moisture M contained in the main steam by the following formula (1).

(In the above formula (1), M represents moisture (%), C _MS-d represents the concentration of lithium (Li) contained in any one of MS drain water, high-pressure drain water, and MSH heated steam drain water. Q _MS-d represents the flow rate of the steam introduced into any one of the drains corresponding to the C _MS-d , C _SG represents the lithium (Li) concentration contained in the SG blowdown water, and Q _{MSR -In} represents the flow rate of the steam introduced into the equipment corresponding to the _CMS-d .)

  According to this configuration, a trace amount of tracer element is added to the secondary cooling water of the main water supply line, and the concentration of the tracer element contained in the SG blowdown (SGBD) water and the drain water of the equipment installed in the main steam line. It was also possible to measure the flow rate of the steam introduced into the equipment installed in the main steam line and calculate the moisture content in the main steam from the obtained tracer element concentration and steam flow rate. Thereby, the moisture in the main steam can be accurately measured by using a trace amount of lithium (Li) element in the tracer.

  The nuclear power plant according to the present invention is characterized in that the feed water flow rate of the secondary cooling water fed to the steam generator is controlled based on the moisture calculated by the main steam moisture measuring device described above.

  According to this configuration, the measurement value obtained by the main steam moisture measuring device can be fed back to the control of the heat output (feed water flow rate) of the steam generator.

  The main steam moisture measuring method of the present invention is a main steam moisture measuring method for measuring the moisture in the main steam, the chemical injection step of adding a tracer element to the secondary cooling water of the feed water line, and steam generation A first steam flow measuring step for measuring the flow rate of the steam introduced into the device arranged between the vessel and the moisture separator heater, and a second for measuring the flow rate of the steam introduced into the drain of the device. A steam flow measurement step, a first measurement step for measuring the tracer element concentration contained in the blow-down water of the steam generator, a second measurement step for measuring the tracer element concentration contained in the drain water of the device, It is contained in the main steam based on the steam flow rate acquired by the first steam flow rate measuring step and the second steam flow rate measuring step and the tracer element concentration acquired by the first measuring step and the second measuring step. A moisture calculating step for calculating moisture, Characterized in that it.

  According to this configuration, a trace amount of tracer element is added to the secondary cooling water of the main water supply line, and the concentration of the tracer element contained in the SG blowdown (SGBD) water and the drain water of the equipment installed in the main steam line. Further, the flow rate of the steam introduced into the equipment installed in the main steam line can be measured, and the moisture content in the main steam can be calculated from the obtained tracer element concentration and the steam flow rate.

  The tracer element of the main vapor moisture measuring method of the present invention is preferably lithium (Li).

  According to this configuration, moisture in the main steam can be accurately measured by using a trace amount of lithium (Li) element for the tracer.

  The chemical injection step of the main steam moisture measuring method of the present invention is installed in the water supply line between the condensate demineralizer and the steam generator, and the tracer element is added to the secondary cooling water flowing therethrough. It is preferable.

  According to this structure, a tracer element can be added to the secondary cooling water of the main water supply line using the existing chemical injection device. Thereby, it is not necessary to install an apparatus for newly adding a tracer element.

  It is preferable that the drain of the apparatus of the main steam moisture measuring method of this invention is the high pressure drain of a high pressure turbine, the MS drain of a moisture separator, and the MSH heating steam drain of a moisture separation heater.

  According to this configuration, it is possible to accurately measure the moisture in the main steam by using a trace amount of lithium (Li) element for the tracer. Thereby, the tracer element concentration can be measured with the addition amount of lithium (Li) at a very low concentration that does not adversely affect the nuclear power plant equipment.

（上記式（１）中、Ｍは湿分（％）を表し、Ｃ_ＭＳ−ｄはＭＳドレン水、高圧ドレン水、ＭＳＨ加熱蒸気ドレン水の何れか一つに含まれるリチウム（Ｌｉ）濃度を表し、Ｑ_ＭＳ−ｄは上記Ｃ_ＭＳ−ｄに対応する何れか一つのドレンに導入された蒸気の流量を表し、Ｃ_ＳＧはＳＧブローダウン水に含まれるリチウム（Ｌｉ）濃度を表し、Ｑ_{ＭＳＲ−ｉｎ}は上記Ｃ_ＭＳ−ｄに対応する機器に導入された蒸気の流量を表す。） In the moisture calculating step of the main steam moisture measuring method of the present invention, it is preferable to calculate the moisture M contained in the main steam by the following formula (1).

(In the above formula (1), M represents moisture (%), C _MS-d represents the concentration of lithium (Li) contained in any one of MS drain water, high-pressure drain water, and MSH heated steam drain water. Q _MS-d represents the flow rate of the steam introduced into any one of the drains corresponding to the C _MS-d , C _SG represents the lithium (Li) concentration contained in the SG blowdown water, and Q _{MSR -In} represents the flow rate of the steam introduced into the equipment corresponding to the _CMS-d .)

  According to this configuration, a trace amount of tracer element is added to the secondary cooling water of the main water supply line, and the concentration of the tracer element contained in the SG blowdown (SGBD) water and the drain water of the equipment installed in the main steam line. It was also possible to measure the flow rate of the steam introduced into the equipment installed in the main steam line and calculate the moisture content in the main steam from the obtained tracer element concentration and steam flow rate. Thereby, the moisture in the main steam can be accurately measured by using a trace amount of lithium (Li) element in the tracer.

  The nuclear power plant according to the present invention is characterized in that the feed water flow rate of the secondary cooling water fed to the steam generator is controlled based on the moisture calculated by the main steam moisture measuring method described above.

  According to this structure, the measured value obtained by the main steam moisture measuring method can be fed back to the control of the heat output (feed water flow rate) of the steam generator.

  According to the main steam moisture measuring device, the main steam moisture measuring method and the nuclear power plant of the present invention, the moisture in the main steam is accurately measured by using a low concentration lithium (Li) element in the tracer. It becomes possible.

FIG. 1 is a schematic configuration diagram schematically showing a nuclear power plant to which a main steam moisture measuring device according to this embodiment is applied. FIG. 2 is a configuration diagram of the main steam moisture measuring device according to the present embodiment. FIG. 3 is a flowchart showing the flow of the main steam moisture measuring method according to the present embodiment.

  Embodiments of a main steam moisture measuring device according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this Example. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram schematically showing a nuclear power plant to which a main steam moisture measuring device according to an embodiment of the present invention is applied.

  The nuclear power plant nuclear reactor to which the present embodiment is applied uses light water as a reactor coolant and neutron moderator, and generates high-temperature and high-pressure water that does not boil throughout the primary system, and sends this high-temperature and high-pressure water to a steam generator. This is a pressurized water reactor (PWR) that generates steam by exchanging heat with the secondary coolant and generates power by sending this steam to a turbine generator. In addition, a present Example is applicable not only to this PWR but the improved pressurized water reactor (APWR: Advanced Pressurized Water Reactor) which improved this. Moreover, it is applicable also to the other power generation plant provided with the steam generator and the steam turbine.

  In a nuclear power plant, normally, high-temperature water using the heat of the reactor is sent to the steam generator for heat exchange and then recovered, and steam is generated using the primary high-temperature water in the steam generator. And a so-called secondary system for generating power by rotating the turbine with this steam and then collecting the steam with a condenser and then collecting it with the steam generator. The secondary system is equipped with an SG (Steam Generator) blowdown system (or steam generator blowdown system) that takes out a portion of the water in the steam generator and purifies impurities before recovering it to the cooling water piping 16. ing. In the SG blowdown system, heat recovery of the fluid blown down is performed as necessary.

  As shown in FIG. 1, a pressurized water reactor 2 and a steam generator 3 are stored in a reactor containment vessel 1 of a pressurized water nuclear plant. The pressurized water reactor 2 and the steam generator 3 are connected via cooling water pipes 4 and 5. The cooling water pipe 4 is provided with a pressurizer 6, and the cooling water pipe 5 is provided with a cooling water pump 7.

  As described above, the nuclear reactor 2 is a pressurized water nuclear reactor, and the inside thereof is filled with a nuclear reactor coolant (primary cooling water). The nuclear reactor 2 accommodates a large number of fuel assemblies, and a large number of control rods for controlling nuclear fuel fission in the fuel rods of the fuel assemblies are provided so as to be insertable into the respective fuel assemblies. .

  When the nuclear fuel in the fuel rod of the fuel assembly is fissioned while controlling the fission reaction with the control rod, thermal energy is generated by this fission. The generated thermal energy heats the reactor coolant, and the heated reactor coolant is sent to the steam generator 3 via the cooling water pipe 4. On the other hand, the reactor coolant sent from each steam generator 3 through the coolant pipe 5 flows into the reactor 2 and cools the reactor 2.

  The steam generator 3 generates steam by evaporating the secondary coolant by exchanging heat with the secondary coolant (secondary coolant) from the high-temperature and high-pressure reactor coolant (primary coolant). And the reactor coolant which became high temperature and high pressure is cooled. The pressurizer 6 suppresses boiling of the reactor coolant by pressurizing the reactor coolant that has reached a high temperature. The cooling water pump 7 circulates the reactor coolant in the reactor cooling system, and sends the reactor coolant from the steam generator 3 to the reactor 2 through the coolant pipe 5 and also supplies the reactor coolant. It is sent from the nuclear reactor 2 to the steam generator 3 through the cooling water pipe 4. The reactor coolant is circulated between the reactor 2 and the steam generator 3. The reactor coolant is light water used as a coolant and a neutron moderator.

  The steam generator 3 is connected to the steam turbine 10 via a cooling water pipe 11. The steam turbine 10 includes a high pressure turbine 10A and a low pressure turbine 10B, and a generator is connected thereto. Further, a moisture separator 26 and a moisture separator / heater 12 are provided between the high pressure turbine 10A and the low pressure turbine 10B. The moisture separator / heater 12 is connected to the high-pressure turbine 10 </ b> A via the low-temperature reheat pipe 13 and is connected to the low-pressure turbine 10 </ b> B via the high-temperature reheat pipe 14. Further, the low pressure turbine 10 </ b> B of the steam turbine 10 has a condenser 15. The condenser 15 is configured to supply and discharge cooling water (for example, seawater). The condenser 15 is connected to a deaerator 17 through a cooling water pipe 16. And in the cooling water piping 16, the condensate pump 18, the condensate desalination apparatus 19, the chemical injection device 40, the condensate booster pump 20, and the low-pressure feed water heater 21 are provided in order from the condenser 15 side. . The deaerator 17 is connected to the steam generator 3 via the cooling water pipe 22. The cooling water pipe 22 is provided with a storage tank 23, a feed water pump 24, and a high-pressure feed water heater 25 in order from the deaerator 17 side. The condensate pump 18, the condensate booster pump 20, and the feed water pump 24 serve as a secondary cooling system for supplying secondary cooling water (pure water) from the condenser 15 via the cooling water pipe 16 by the condensate pump 18. It is sent to the water demineralizer 19 and sent to the deaerator 17 via the cooling water pipe 16 via the low pressure feed water heater 21 by the condensate booster pump 20. And secondary cooling water is sent to the steam generator 3 through the high pressure feed water heater 25 via the cooling water piping 22 by the feed water pump 24. In addition, the secondary cooling water deaerated by the deaerator 17 is sent from the deaerator 17 through the cooling water pipe 22.

  Steam of the secondary cooling water generated by exchanging heat with the high-pressure and high-temperature primary cooling water in the steam generator 3 is distributed to the high-pressure turbine 10 </ b> A and the low-temperature reheat pipe 13 through the cooling water pipe 11. This distribution rate is arbitrarily set. The steam distributed to the high-pressure turbine 10A is introduced into the high-pressure heater 27 after driving the high-pressure turbine 10A. The liquid separated by the high-pressure heater 27 is collected in a high-pressure drain (HP drain) 27a. The high-pressure exhaust of the high-pressure turbine 10 </ b> A is introduced into the moisture separator 26, the separated liquid is collected in an MS (Moisture Separator) drain 26 a, and the gas is sent to the moisture separator / heater 12. A moisture separator / heater (MSH: Moisture Separator Heater) 12 heats the steam distributed and introduced into the low-temperature reheat pipe 13 and separates it into a liquid and a gas. The liquid separated by the moisture separator / heater 12 is collected in a moisture separator / heater heating steam drain (MSH heating steam drain) 12a. The gas separated by the moisture separator / heater 12 and the gas sent from the moisture separator 26 are sent to the low-pressure turbine 10 </ b> B via the high-temperature reheat pipe 14. The steam turbine 10 (the high-pressure turbine 10A and the low-pressure turbine 10B) is driven by this steam (gas), and power is generated by the generator. That is, the steam from the steam generator 3 drives the high-pressure turbine 10A, and then the moisture contained in the steam is removed by the moisture separator / heater 12, and the low-pressure turbine 10B is driven after being heated.

  The steam that has driven the steam turbine 10 (the high-pressure turbine 10A and the low-pressure turbine 10B) is cooled by the condenser 15 and becomes liquid. In the condensate demineralizer 19, the seawater component contained in the condensate is removed. Condensate (secondary cooling water) is adjusted in pH by the chemical injection device 40 and heated by the low-pressure steam extracted from the low-pressure turbine 10B by the low-pressure feed water heater 21, and then sent to the deaerator 17 to be dissolved oxygen. And impurities such as non-condensable gas (ammonia gas) are removed. Thereafter, the secondary cooling water (condensate) is temporarily stored in the storage tank 23, heated by the high-pressure steam extracted from the high-pressure turbine 10 </ b> A by the high-pressure feed water heater 25, and then returned to the steam generator 3. In addition, as a pH adjustment chemical | medical agent of secondary cooling water (condensate), well-known chemical | medical agents, such as ammonia and a hydrazine, are applicable, for example.

  Further, in the low pressure feed water heater 21, the condensed water in which the low pressure steam is condensed is drained to the cooling water pipe 22 through the low pressure feed water heater drain by the low pressure feed water heater drain pump. In addition, you may drain the condensed water of the low voltage | pressure feed water heater 21 to the condenser 15. FIG. Moreover, in the high pressure feed water heater 25, the condensed water in which the high pressure steam is condensed is drained to the deaerator 17 through the low pressure feed water heater drain by the high pressure feed water heater drain pump. The condensed water from the high-pressure feed water heater 25 may be drained to the condenser 15.

  The SG blowdown system has the following main components. The steam generator 3 includes an SGBD (Steam Generator Blow Down) tube 29. An SGBD shutoff valve 32 and an SGBD throttle valve 33 are provided in the middle of the SGBD pipe 29. The SGBD pipe 29 is connected to a flash tank (F / T) 30 on the downstream side of the SGBD throttle valve 33. A blow-down service line 34 is disposed downstream of the flash tank 30. One end of the blowdown service line 34 is connected to the flash tank 30, the SGBD cooler 35 and the first F / T water level control valve 36 are provided in the middle, the other end is downstream of the condensate pump 18, and It is connected to the upstream portion of the condensate demineralizer 19. A blowdown bypass line 37 is branched from the blowdown service line 34 on the downstream side of the flash tank 30 and the upstream side of the SGBD cooler 35. The blowdown bypass line 37 is provided with a second F / T water level control valve 38 in the middle. The blow-down bypass line 37 has one end connected to the flash tank 30 and the other end connected to the condenser 15. Here, the first F / T water level control valve 36 and the second F / T water level control valve 38 are flow rate adjustment valves capable of adjusting the flow rate, and constitute a flow path determining means.

  Further, the flash tank 30 is provided with a heat recovery line 31 that is downstream of the low-pressure feed water heater 21 and connected to the deaerator 17. The vapor separated in the flash tank 30 is sent to the deaerator 17 through the heat recovery line 31.

  In a nuclear power plant equipped with such an SG blowdown system, during normal operation, for example, the SGBD shut-off valve 32 and the switching valve are automatically controlled, and the fluid blown down by the steam generator 3 is supplied to the SG blowdown system. As shown in FIG. The flash vapor flashed in the flash tank 30 is collected in the deaerator 17. The remaining liquid is introduced into the SGBD cooler 35 as an SG blowdown liquid, cooled to below the allowable temperature of the condensate demineralizer 19, and then condensed via the first F / T water level control valve 36. It is sent to the desalinator 19. The allowable temperature of the condensate demineralizer 19 is a value determined from the heat resistance temperature of the ion exchange resin of the condensate demineralizer 19, and is about 40 ° C., for example.

<Main steam moisture measuring device>
Next, the main steam moisture measuring device of the present embodiment will be described.

  The main steam moisture measuring device of this embodiment adds a trace amount of tracer element to the secondary cooling water of the main water supply line, and generates a steam generator blow-down (hereinafter referred to as SG blow-down) underwater and main steam line. Measure the concentration of tracer element contained in the drain water of the equipment installed in the equipment and the flow rate of the steam introduced into the equipment installed in the main steam line. It is characterized by calculating moisture. By doing in this way, it became possible to measure the moisture in the main steam with high accuracy even when a trace amount of lithium (Li) element was used for the tracer. In addition, by applying a high frequency inductively coupled plasma mass spectrometer (ICP-MS) to the tracer element concentration measurement unit, it is possible to measure the tracer element concentration with a very low concentration of lithium that does not adversely affect the nuclear power plant equipment. It has become possible.

  FIG. 2 is a configuration diagram of the main steam moisture measuring device according to the present embodiment. Components similar to those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In the following description, the moisture separator 26 and the MS drain 26a will be described as an example, but the present invention is not limited thereto.

  The main steam moisture measuring apparatus 100 according to the embodiment includes a measurement unit 101, a control unit 102, a storage unit 103, a calculation unit 104, an output unit 105, a display unit 106, a drug injection unit 40, a first sample extraction unit S1, and a second sample extraction unit S1. Sample extraction unit S2, third sample extraction unit S3, fourth sample extraction unit S4 and first steam flow rate measurement unit f1, second steam flow rate measurement unit f2, third steam flow rate measurement unit f3, fourth steam flow rate measurement unit f4 Including.

  The measuring unit 101 performs element identification and quantification by introducing atoms ionized by inductively coupled plasma (abbreviated as ICP) into a mass spectrometer (abbreviated as MS). It is a plasma mass spectrometer (ICP-MS). In the present embodiment, since a mass spectrometer is used, an ultrasensitive analysis at the ppt level is possible. A known apparatus can be applied to the inductively coupled plasma mass spectrometer applied to the measurement unit 101. In general, since a high frequency inductively coupled plasma mass spectrometer is installed in a nuclear power plant for water quality management or the like, this existing apparatus can be configured as the measuring unit 101.

  The control part 102 controls the main steam moisture measuring apparatus 100 whole. The control unit 102 also exchanges information with the inductively coupled plasma mass spectrometer that constitutes the measuring unit 101, stores the tracer element concentration measured by the inductively coupled plasma mass spectrometer in the storage unit 103, and stores the moisture in the arithmetic unit 104. Is calculated. Further, the control unit 102 causes the output unit 105 and the display unit 106 to output information such as the calculated value. The control unit 102 exchanges information with the first steam flow measurement unit f1, the second steam flow measurement unit f2, the third steam flow measurement unit f3, and the fourth steam flow measurement unit f4 to exchange the information with the first steam flow measurement unit f1, The steam flow rate measured by the second steam flow rate measurement unit f2, the third steam flow rate measurement unit f3, and the fourth steam flow rate measurement unit f4 is stored in the storage unit 103, and the calculation unit 104 calculates moisture. Further, the control unit 102 controls the medicine injection unit 40 to add the tracer element to the secondary cooling water of the main water supply line.

  The storage unit 103 is measured by the tracer element concentration measured by the measuring unit 101 and the first steam flow rate measuring unit f1, the second steam flow rate measuring unit f2, the third steam flow rate measuring unit f3, and the fourth steam flow rate measuring unit f4. Stores steam flow etc.

  The computing unit 104 is measured by the tracer element concentration measured by the measuring unit 101 and the first steam flow rate measuring unit f1, the second steam flow rate measuring unit f2, the third steam flow rate measuring unit f3, and the fourth steam flow rate measuring unit f4. Calculate the moisture based on the steam flow rate.

  The output unit 105 and the display unit 106 output and display various types of information.

  The chemical injection unit 40 adds the tracer element to the secondary cooling water of the main water supply line that is the target of the tracer element concentration measurement. The pH that varies due to the addition of the tracer element can be adjusted by a known method. Suitable tracer elements include sodium (Na) and lithium (Li). When seawater is used for reactor auxiliary coolant (CCW), sodium (Na) is a measurement target as a tracer element for detecting seawater leaks, so lithium is added as a tracer element to be added. (Li) is more preferred. In particular, lithium (Li) is an element that does not generally exist in nature. Therefore, even if mixed in secondary cooling water, there is a low risk of causing measurement errors. LiOH added as a tracer element is alkaline and is concentrated with SG clevis. Since the heat transfer tube or the like may cause intergranular corrosion cracking (IGA: Intergranular Attack) due to the alkaline environment around the SG clevis, the addition amount of lithium (Li) is preferably extremely small. Here, the SG clevis means a gap between the heat transfer tube periphery of the steam generator and the tube support plate that supports the heat transfer tube.

  The first sample extraction unit S1, the second sample extraction unit S2, the third sample extraction unit S3, and the fourth sample extraction unit S4 are portions for extracting a sample (sample water) for measuring the added tracer element concentration. is there. 1st sample extraction part S1 is a part which extracts SG blowdown water. The second sample extraction unit S2 is a part that extracts the HP drain 27a water of the high-pressure turbine 10A. The third sample extraction unit S3 is a part for extracting the MS drain 26a water of the moisture separator 26. The fourth sample extraction unit S4 is a part for extracting the MSH heating steam drain 12a water of the moisture separation heater 12. The tracer element concentration contained in the main water supply line can be measured by the first sample extraction unit S1. In this embodiment, the first sample extraction unit S1 is the first measurement unit. The tracer element concentration measured by the second sample extraction unit S2, the third sample extraction unit S3, and the fourth sample extraction unit S4 is the tracer element concentration contained in the main steam generated by the steam generator 3. In the present embodiment, the second sample extraction unit S2, the third sample extraction unit S3, and the fourth sample extraction unit S4 correspond to the second measurement unit. The tracer element concentration level measured by the second sample extraction unit S2, the third sample extraction unit S3, and the fourth sample extraction unit S4 varies depending on the distribution rate (steam flow rate) at which the main steam is distributed to each device. For example, the tracer element concentration measured by the MS drain 26a (third sample extraction unit S3) of the moisture separator 26 having a high distribution rate is measured by the HP drain 27a (second sample extraction unit S2) of the high-pressure turbine 10A. It is known that the value is an order of magnitude higher than the tracer element concentration. Therefore, the sample for measuring the tracer element concentration is preferably the sample of the third sample extraction unit S3.

  The first steam flow measurement unit f1, the second steam flow measurement unit f2, the third steam flow measurement unit f3, and the fourth steam flow measurement unit f4 distribute the main steam generated by the steam generator 3 and introduce it to each device. It is a part that measures the flow rate of the generated steam. The first steam flow measurement unit f1 is a part that measures the flow rate of the steam introduced from the high-pressure exhaust of the high-pressure turbine 10A into the moisture separator 26. The second steam flow rate measurement unit f2 is a part that measures the flow rate of the steam introduced into the HP drain 27a from the steam that has driven the high-pressure turbine 10A. The third steam flow rate measurement unit f3 is a part that measures the flow rate of the steam introduced from the moisture separator 26 into the MS drain 26a. The fourth steam flow rate measuring unit f4 is a part that measures the flow rate of the steam introduced from the moisture separation heater 12 into the MSH heating steam drain 12a. In the present embodiment, the first steam flow rate measuring unit f1 is the first steam flow rate measuring unit. Further, the second steam flow measuring unit f2, the third steam flow measuring unit f3, and the fourth steam flow measuring unit f4 described above correspond to the second steam flow measuring unit. Since the steam flow measured by the first steam flow measurement unit f1, the second steam flow measurement unit f2, the third steam flow measurement unit f3, and the fourth steam flow measurement unit f4 varies depending on the operating state of the nuclear power plant, It is also possible to calculate the moisture in the main steam using a design value calculated based on a preset steam flow distribution ratio as the value of the flow rate of the steam introduced into each device.

<Main steam moisture measurement method>
Next, the main steam moisture measuring method of the present embodiment will be described with reference to FIG.

  FIG. 3 is a flowchart showing the flow of the main steam moisture measuring method according to the present embodiment. Hereinafter, the moisture separator and the MS drain will be described as an example, but the present invention is not limited to this.

  The measurement part 101 measures the impurity concentration of SG blowdown water (1st sample extraction part S1), before adding lithium (Li) as a tracer element to the secondary cooling water of a main water supply line (step S10). Based on the measured impurity concentration, the calculation unit 104 calculates SG clevis pH. Next, the operation unit 104 estimates the SG clevis pH after the addition of lithium (Li), and the control unit 102 sets the lithium addition amount based on the estimated value (step S11). Since SG clevis is in a high temperature atmosphere when the steam generator is operating, it is preferable to set the amount of lithium added so that the SG clevis pH in the high temperature atmosphere is 4 or more and 11 or less. More preferably, the amount of lithium added is set so that the SG clevis pH is 5 or more and 10 or less.

  As the chemical injection step, the control unit 102 sets the amount of lithium added as a tracer element, and then controls the chemical injection unit 40 to add lithium to the secondary cooling water in the main water supply line (step S12). The addition of lithium to the main water supply line can be performed using, for example, the drug tank of the drug injection device 40 in FIG. Thereby, it is not necessary to install an apparatus or the like for newly adding lithium. The drug injection device 40 is for managing water quality such as pH and dissolved oxygen concentration of the secondary cooling water in the main water supply line, and is a device for injecting a drug such as hydrazine. In this embodiment, lithium is mixed in the hydrazine injection tank and the tracer element lithium is added to the secondary cold water in the main water supply line. Lithium as well as hydrazine has a function of changing the pH. The lithium concentration in the hydrazine injection tank can be adjusted by adjusting the hydrazine charging rate.

  The measuring unit 101 adds the lithium, and after a predetermined time has elapsed, after the lithium concentration in the secondary cold water and the SG blowdown water in the main water supply line is stabilized, the SG of the steam generator 3 is used as the first measuring step. The lithium concentration contained in the blowdown water is measured (step S13). The lithium concentration measurement is performed by introducing SG blowdown water from the first sample extraction unit S1 in FIG. 2 into the measurement unit 101 of the main steam moisture measuring device 100 through a sampling tube. The lithium concentration contained in the SG blowdown water measured by the measurement unit 101 is transmitted from the measurement unit 101 to the control unit 102 and stored in the storage unit 103.

  Next, the controller 102 distributes the main steam from the main steam as the first steam flow measuring step and introduces the MS from the moisture separator 26 as the second steam flow measuring step and the second steam flow measuring step. The flow rate of the steam introduced into the drain 26a is measured (step S14). The steam flow measurement is performed by the first steam flow measurement unit f1 (flow rate of the steam introduced into the moisture separator 26) and the third steam flow measurement unit f3 (from the moisture separator 26 to the MS drain 26a) in FIG. For example, a known mass flow meter is installed at the flow rate of the vapor. The measured steam flow rate of each steam flow rate measuring unit is transmitted to the control unit 102 of the main steam moisture measuring device 100 and stored in the storage unit 103. The vapor flow rate measurement is not limited to the above-described mass flow meter, and any device that can measure the flow rate of a known fluid can be applied.

  The control unit 102 measures the concentration of lithium contained in the MS drain 26a water in the measurement unit 101 as a second measurement step at the same time as measuring the steam flow rate (step S15). The lithium concentration measurement is performed by introducing the MS drain 26a water from the third sample extraction unit S3 in FIG. 2 into the measurement unit 101 of the main steam moisture measurement device 100 via, for example, a sampling tube. . The lithium concentration contained in the MS drain 26 a water measured by the measurement unit 101 is transmitted from the measurement unit 101 to the control unit 102 and stored in the storage unit 103.

  Next, the control unit 101 uses the following equation (1) to calculate the humidity in the main steam from each lithium concentration and each steam flow rate acquired in the above steps S13, S14, and S15 as a moisture calculation step. The minute M is calculated (step S16).

上記式（１）中、Ｍは湿分（％）を表し、Ｃ_ＭＳ−ｄはＭＳドレン水に含まれるリチウム（Ｌｉ）濃度（ｐｐｍ）を表し、Ｑ_ＭＳ−ｄは上記Ｃ_ＭＳ−ｄに対応するＭＳドレンに導入された蒸気の流量（ｋｇ／時間）を表し、Ｃ_ＳＧはＳＧブローダウン水に含まれるリチウム（Ｌｉ）濃度（ｐｐｍ）を表し、Ｑ_{ＭＳＲ−ｉｎ}は上記Ｃ_ＭＳ−ｄに対応する湿分分離器に導入された蒸気の流量（ｋｇ／時間）を表す。

In the above formula (1), M represents moisture (%), C _MS-d represents the lithium (Li) concentration (ppm) contained in the MS drain water, and Q _MS-d represents the above C _MS-d . It represents the flow rate (kg / hour) of steam introduced into the corresponding MS drain, C _SG represents the lithium (Li) concentration (ppm) contained in SG blowdown water, and Q _MSR-in represents the above C _MS-d Represents the flow rate (kg / hour) of steam introduced into the moisture separator corresponding to.

  In the above-described embodiment, the vapor flow rate measurement and the lithium concentration measurement are described as examples in which the moisture separator 26 and the MS drain 26a are measurement objects. When the steam flow measurement and the lithium concentration measurement are for the high-pressure turbine 10A and the HP drain 27a, the steam flow is distributed from the main steam and the steam flow introduced into the high-pressure turbine 10A is introduced into the entire HP drain 27a. As a result, the moisture M is calculated. Further, the steam flow rate is measured by the second steam flow rate measuring unit f2. The lithium concentration measurement is performed by introducing the HP drain 27a water from the second sample extraction unit S2 in FIG. 2 into the measuring unit 101 of the main steam moisture measuring device 100 through a sampling tube, for example. . In addition, when the steam flow measurement and the lithium concentration measurement are performed on the moisture separation heater 12 and the MSH heating steam drain 12a, the steam flow is distributed from the main steam and is introduced into the low-temperature reheat pipe 13. And the flow rate of the steam introduced from the moisture separator 26. The moisture M is calculated on the assumption that the added steam flow rate is introduced into the moisture separation heater 12. The amount of steam introduced into the MSH heating steam drain 12a is measured by the fourth steam flow rate measuring unit f4. The lithium concentration measurement is performed by introducing the MSH heating steam drain 12a water from the sample extraction unit S4 in FIG. 2 into the measuring unit 101 of the main steam moisture measuring device 100 through a sampling tube, for example. .

  In the above description, the lithium concentration is measured from the first sample extraction unit S1, the second sample extraction unit S2, the third sample extraction unit S3, the fourth sample extraction unit S4 via the sampling tube, and the main steam moisture measuring device 100. The sample (sample water) collected by the first sample extraction unit S1, the second sample extraction unit S2, the third sample extraction unit S3, and the fourth sample extraction unit S4 is mainly used. It is also possible to adopt a configuration in which the measurement is performed by bringing it into the vapor moisture measuring device 100 and introducing it into the measuring unit 101 in a batch manner.

<Application example of main steam moisture measurement method>
Next, an example in which moisture is calculated by applying the main steam moisture measurement method of this embodiment will be described. The impurity concentration of SG blowdown water was measured before adding lithium (Li) as a tracer element to the secondary cooling water in the main water supply line. Then, based on the measured impurity concentration, the SG clevis pH after addition of lithium was estimated to be 9 or less, and the lithium addition amount was set. At this time, the background concentration of lithium in the secondary cooling water of the main water supply line before lithium addition was 0.2 ppt or less. As a method for setting and confirming SG clevis pH, a conventionally known method can be applied.

Next, the lithium addition amount set above was added to the drug tank (hydrazine tank) of the drug injection device 40 shown in FIG. At this time, SG clevis pH was set to be 4 or more and 11 or less. Moreover, the lithium concentration of the added lithium-added stock solution was adjusted to 0.09 mass% or more and 0.11 mass% or less. The impurity concentration of the lithium-added stock solution was 10 ppm or less for all of sodium (Na), chlorine (Cl), and sulfate ions (SO ₄ ).

After elapse of a predetermined time after adding lithium, the lithium concentration in each part was measured after the lithium concentration in the secondary cold water and SG blowdown water in the main water supply line was stabilized. The measured lithium concentration is as shown below.
・ Lithium concentration of SG blowdown water: 1 ppb
・ Lithium concentration of HP drain water: 1ppt
・ Lithium concentration of MS drain water: 10ppt

At the same time, the flow rate of the steam introduced into the HP drain and the MS drain was measured, and the steam flow distribution ratio of the main steam was calculated. The calculated steam flow rate distribution ratio is as shown below.
-HP drain: MS drain = 1:10

From the above results, the moisture in the main steam of each part calculated by applying the above formula (1) is as shown below.
・ HP drain 0.1%
・ MS drain 0.1%

  Therefore, the moisture contained in the main steam generated by the steam generator (SG) detected by each drain was about 0.1%. As a rough guide, the moisture detected with the HP drain is about 1/1000 of the SG blowdown moisture, and the moisture detected with the MS drain is about 1/100 of the SG blowdown moisture. It is. In other words, it can be seen that the lithium detection concentration in the MS drain is an order of magnitude higher than that in the HP drain. Here, since the steam flow rate distribution ratio of the main steam described above is HP drain: MS drain- = 1: 10, when the moisture content in the main steam is calculated in consideration of the steam flow rate distribution ratio, HP drain = MS Drain = 0.1%. For example, when the moisture of SG blow down (SGBD) is 100%, the moisture with HP drain or MS drain can be estimated to be about 0.1%.

  Thus, according to the present embodiment, a trace amount of tracer element is added to the secondary cooling water of the main water supply line, and in the SG blowdown (SGBD) water and the drain water of the equipment installed in the main steam line. It is possible to measure the tracer element concentration and the flow rate of steam introduced into equipment installed in the main steam line, and to calculate the moisture content in the main steam from the obtained tracer element concentration and steam flow rate. It was.

  Further, by using a trace amount of lithium (Li) element for the tracer, it becomes possible to accurately measure the moisture in the main steam.

  Also, by applying a high frequency inductively coupled plasma mass spectrometer (ICP-MS) to the tracer element concentration measurement, the tracer element concentration is measured with an extremely low concentration of lithium (Li) added that does not adversely affect the nuclear power plant equipment. It became possible.

2 Pressurized water reactor 3 Steam generator 10 Steam turbine 10A High-pressure turbine (HP-T)
10B Low pressure turbine (LP-T)
12 Moisture separation heater (MSH)
12a MSH heating steam drain 13 Low temperature reheat pipe 14 High temperature reheat pipe 15 Condenser 16, 22 Cooling water piping 17 Deaerator 18 Condensate pump 19 Condensate demineralizer 20 Condensate booster pump 21 Low pressure feed water heater 24 Feed pump 25 High pressure feed water heater 26 Moisture separator 26a MS drain 27 High pressure heater 27a High pressure drain (HP drain)
29 SGBD pipe (SG blowdown pipe)
30 Flash tank (F / T)
32 SGBD shutoff valve 34 Blowdown service line 40 Drug injection device 100 Main steam moisture measuring device 101 Measuring unit 102 Control unit 103 Storage unit 104 Calculation unit 105 Output unit 106 Display unit S1, S2, S3, S4 Sample extraction unit f1, f2, f3, f4 Steam flow measurement unit

Claims (12)

A main steam moisture measuring device for measuring moisture in main steam,
A chemical injection part for adding a tracer element to the secondary cooling water of the water supply line;
A first steam flow measurement unit for measuring a flow rate of steam introduced into an apparatus disposed between the steam generator and the moisture separation heater;
A second steam flow measuring unit that measures the flow rate of steam introduced into a drain of another device different from the device measured by the first steam flow measuring unit;
A first measurement unit for measuring the concentration of the tracer element contained in blowdown water of the steam generator;
A second measuring unit for measuring the concentration of the tracer element contained in the drain water of the other device;
Based on the steam flow rate acquired by the first steam flow rate measurement unit and the second vapor flow rate measurement unit, and the tracer element concentration acquired by the first measurement unit and the second measurement unit. A moisture calculation unit for calculating the moisture contained in the main steam;
A main steam moisture measuring device.   The main vapor moisture measuring apparatus according to claim 1, wherein the tracer element is lithium (Li).   The said chemical | medical agent injection | pouring part is installed in the water supply line between a condensate demineralizer and the said steam generator, The said tracer element is added to the secondary cooling water which flows through this, The Claim 1 characterized by the above-mentioned. Main vapor moisture measuring device as described. The drains of the other equipment measured by the second steam flow meter side are the high pressure drain of the high pressure turbine, the MS drain of the moisture separator, and the MSH heating steam drain of the moisture separation heater. The main steam moisture measuring device according to claim 1. The said moisture calculation part calculates the moisture M contained in the said main steam by following formula (1), The main steam moisture measuring apparatus of any one of Claim 1 to 4 characterized by the above-mentioned. .

(In the above formula (1), M represents moisture (%), C _MS-d represents the concentration of lithium (Li) contained in any one of MS drain water, high-pressure drain water, and MSH heated steam drain water. Q _MS-d represents the flow rate of the steam introduced into any one of the drains corresponding to the C _MS-d , C _SG represents the lithium (Li) concentration contained in the SG blowdown water, and Q _{MSR -In} represents the flow rate of the steam introduced into the equipment corresponding to the _CMS-d .)   The feed water flow rate of the secondary cooling water fed to the steam generator is controlled based on the moisture calculated by the main steam moisture measuring device according to any one of claims 1 to 5. Nuclear power plant. A main steam moisture measuring method for measuring moisture in main steam,
A chemical injection step of adding a tracer element to the secondary cooling water of the water supply line;
A first steam flow measuring step for measuring a flow rate of steam introduced into equipment disposed between the steam generator and the moisture separator heater;
A second steam flow measuring step for measuring a flow rate of steam introduced into a drain of another device different from the device measured by the first steam flow measuring unit ;
A first measurement step of measuring the tracer element concentration contained in blowdown water of the steam generator;
A second measurement step of measuring the tracer element concentration contained in the drain water of the other device;
Based on the flow rate of the steam acquired by the first steam flow rate measurement step and the second steam flow rate measurement step, and the tracer element concentration acquired by the first measurement step and the second measurement step. A moisture calculating step for calculating the moisture contained in the main steam;
A method for measuring main steam moisture, comprising:   The main vapor moisture measuring method according to claim 7, wherein the tracer element is lithium (Li).   The said chemical | medical agent injection | pouring process is installed in the water supply line between a condensate desalination apparatus and the said steam generator, The said tracer element is added to the secondary cooling water which flows through this, The said tracer element is characterized by the above-mentioned. The main steam moisture measuring method described. The drains of the other equipment measured by the second steam flow meter side are the high pressure drain of the high pressure turbine, the MS drain of the moisture separator, and the MSH heating steam drain of the moisture separation heater. The main steam moisture measuring method according to claim 7. 11. The main steam moisture measuring method according to claim 7, wherein the moisture calculating step calculates the moisture M contained in the main steam by the following formula (1). .

(In the above formula (1), M represents moisture (%), C _MS-d represents the concentration of lithium (Li) contained in any one of MS drain water, high-pressure drain water, and MSH heated steam drain water. Q _MS-d represents the flow rate of the steam introduced into any one of the drains corresponding to the C _MS-d , C _SG represents the lithium (Li) concentration contained in the SG blowdown water, and Q _{MSR -In} represents the flow rate of the steam introduced into the equipment corresponding to the _CMS-d .)   The feed water flow rate of the secondary cooling water fed to the steam generator is controlled based on the moisture calculated by the main steam moisture measuring method according to any one of claims 7 to 11. Nuclear power plant.

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