Heavy water quality monitoring and hierarchical storage system

Abstract

The present application belongs to the technical field of heavy water quality monitoring, and particularly relates to a heavy water quality monitoring and hierarchical storage system, which is used for monitoring and hierarchically storing heavy water after upgrading treatment by a front-stage purification unit (1), and comprises an electric conductivity and flow monitoring unit and a heavy water concentration online analysis unit connected through a third pipeline (10), the electric conductivity and flow monitoring unit being connected at a downstream end of the front-stage purification unit (1), and further comprising a heavy water storage system connected with the electric conductivity and flow monitoring unit and the heavy water concentration online analysis unit. The present application uses the working principle of an electromagnetic flowmeter, and innovatively integrates the electric conductivity monitoring and flow monitoring functions, thereby eliminating the installation of an electric conductivity meter, reducing the use cost, facilitating installation, and automatically regulating the heavy water destination according to relevant measurement results, so as to realize automatic water quality detection and hierarchical storage of heavy water.

Description

Technical Field

[0001] This invention belongs to the field of heavy water quality monitoring technology, specifically relating to a heavy water quality monitoring and hierarchical storage system. Background Technology

[0002] Heavy water has a small thermal neutron absorption cross section and good neutron economy, making it a high-quality moderator for heavy water reactors. However, deuterium in the heavy water moderator can undergo neutron capture reactions to produce tritium, causing inconvenience to reactor operation and maintenance. Furthermore, heavy water leakage is inevitable during reactor operation, leading to the introduction of protium through exchange with light water in the environment, causing a decrease in heavy water concentration and quality degradation. To maintain the cleanliness of reactor heavy water, it is necessary to upgrade the heavy water used as a moderator in nuclear power plants. The quality of the upgraded heavy water needs to be strictly monitored to meet the requirements for use as a reactor moderator. Currently, the quality of upgraded heavy water is mostly measured offline in stages, meaning that samples are taken and measured separately according to testing needs, and the quality level and storage destination can only be determined after all test results are obtained. This lacks an automated quality monitoring and tiered storage system. Summary of the Invention

[0003] The purpose of this invention is to provide a heavy water quality monitoring system. This system interlocks online analysis and measurement equipment with pipeline switching equipment, automatically adjusting the direction of heavy water based on relevant measurement results, thereby achieving automatic water quality detection and graded storage.

[0004] To achieve the above objectives, the present invention employs a heavy water quality monitoring and graded storage system, which is used to monitor and grade heavy water after it has undergone upgrade treatment by a pre-purification unit. The system includes a conductivity and flow rate monitoring unit and a heavy water concentration online analysis unit connected via a third pipeline. The conductivity and flow rate monitoring unit is connected downstream of the pre-purification unit. The system also includes a heavy water storage system connected to the conductivity and flow rate monitoring unit and the heavy water concentration online analysis unit.

[0005] further,

[0006] The heavy water storage system includes a low-level heavy water storage tank, a medium-level heavy water storage tank, and a high-level heavy water storage tank.

[0007] It also includes a first pipeline, the top end of which is connected to the pre-purification unit, and the tail end of which is connected to the conductivity and flow monitoring unit.

[0008] It also includes a fourth pipeline, the top end of which is connected to the rear end of the conductivity and flow monitoring unit, and the tail end of which is connected to the low-grade heavy water storage tank.

[0009] The conductivity and flow monitoring unit is provided with a first output tube at its rear end. The top end of the first output tube is connected to the rear end of the conductivity and flow monitoring unit, and the tail end of the first output tube serves as the first outlet. The top ends of the third pipeline and the top ends of the fourth pipeline converge at the first outlet and are connected to the conductivity and flow monitoring unit through the first output tube.

[0010] It also includes a fifth pipeline, the top end of which is connected to the rear end of the heavy water concentration online analysis unit, and the tail end of which is connected to the high-grade heavy water storage tank.

[0011] It also includes a sixth pipeline, the top end of which is connected to the rear end of the heavy water concentration online analysis unit, and the tail end of which is connected to the intermediate heavy water storage tank.

[0012] The heavy water concentration online analysis unit is provided with a second output pipe at the rear end. The top end of the second output pipe is connected to the rear end of the heavy water concentration online analysis unit, and the tail end of the second output pipe serves as a second outlet. The top ends of the fifth pipeline and the sixth pipeline converge at the second outlet and are connected to the heavy water concentration online analysis unit through the second output pipe.

[0013] Furthermore, the first, third, fourth, fifth, and sixth pipelines are all controlled by valve assemblies with communication operation capabilities, such as solenoid valves; each of the first, third, fourth, fifth, and sixth pipelines is equipped with flow meters and pressure gauges to measure the flow rate and pressure of heavy water at the corresponding locations; maintenance valves and bypasses are installed at both ends of the conductivity and flow monitoring unit and the online heavy water concentration analysis unit to facilitate maintenance and component replacement.

[0014] Furthermore, it also includes a control terminal, which is used to control the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly. The monitoring variable values, analysis results, and control signals of the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly are all transmitted to the control terminal via a PLC. The control terminal is responsible for signal parsing, value comparison, classification judgment, component control, and cumulative calculation, and comprehensively regulates the flow status of each pipeline so that the heavy water of the corresponding heavy water concentration flows into the corresponding level of heavy water storage tank.

[0015] further,

[0016] The conductivity and flow rate monitoring unit is used to perform the first analysis of the heavy water and the first classification of the heavy water;

[0017] The first classification includes transporting the heavy water that passes the first analysis to the online heavy water concentration analysis unit for a second analysis, and transporting the heavy water that fails the first analysis to the low-grade heavy water storage tank for storage.

[0018] The first analysis refers to monitoring the conductivity of the heavy water after the upgraded treatment by the pre-purification unit. If the conductivity of the heavy water is qualified, the first analysis result is qualified; otherwise, the first analysis result is unqualified.

[0019] further,

[0020] The conductivity and flow monitoring unit includes a pre-stage output flow controller and an electromagnetic flow meter connected in series via a second pipeline, with the pre-stage output flow controller located near the downstream end of the pre-stage purification unit.

[0021] The pre-stage output flow controller is used to interlock the start of the heavy water quality monitoring and graded storage system. The heavy water quality monitoring and graded storage system can only be interlocked when the heavy water delivered by the pre-stage purification unit meets the set flow limit.

[0022] The electromagnetic flowmeter is used to monitor the flow rate of the heavy water and also for the first analysis to determine whether the conductivity of the heavy water is qualified.

[0023] Furthermore, the first classification includes the following two cases:

[0024] In the first scenario, if the reading of the electromagnetic flowmeter is consistent with the delivery flow of the pre-purification unit, i.e., the reading of the pre-output flow controller, and remains stable, then the conductivity of the heavy water is unqualified. The control terminal will automatically connect the valve assembly of the pipeline path to the low-level heavy water storage tank to transport the heavy water with unqualified conductivity to the low-level heavy water storage tank for temporary storage, pending subsequent processing. At the same time, by connecting and accumulating the delivery flow of the pre-purification unit, i.e., the heavy water flow through the pre-output flow controller, the liquid storage volume in the low-level heavy water storage tank is determined.

[0025] The second method is as follows: if the reading of the electromagnetic flowmeter fluctuates abnormally, and the delivery flow of the pre-purification unit, i.e. the reading of the pre-output flow controller, is stable, then the conductivity of the heavy water is qualified. The control terminal will automatically associate and open the valve assembly of the path to the online heavy water concentration analysis unit, and deliver the heavy water with qualified conductivity to the online heavy water concentration analysis unit for further analysis.

[0026] Simultaneously, the pressure of heavy water at corresponding points on the pipeline is monitored using the pressure gauge;

[0027] In the first scenario, the criterion for determining whether the reading of the electromagnetic flowmeter is consistent and stable with the reading of the upstream output flow controller is jointly determined by the measurement accuracy of the electromagnetic flowmeter and the measurement accuracy of the upstream output flow controller. When the reading of the electromagnetic flowmeter is consistent and stable with the reading of the upstream output flow controller, the difference between the reading of the electromagnetic flowmeter and the reading of the upstream output flow controller is not higher than 5 times the measurement accuracy of the larger of the measurement accuracy of the electromagnetic flowmeter and the upstream output flow controller. Furthermore, the fluctuation of the reading of the electromagnetic flowmeter should be within the same order of magnitude as the measurement accuracy of the electromagnetic flowmeter, preferably not exceeding 3 times the measurement accuracy of the electromagnetic flowmeter.

[0028] In the second case, the abnormal fluctuation of the electromagnetic flowmeter reading means that the difference between the reading of the electromagnetic flowmeter and the reading of the upstream output flow controller is not less than 30 times the measurement accuracy of the electromagnetic flowmeter.

[0029] In the second scenario, the criterion for judging the stability of the delivery flow of the pre-purification unit is determined by the measurement accuracy of the pre-output flow controller. When the delivery flow of the pre-purification unit is stable, the fluctuation of the reading of the pre-output flow controller should be on the same order of magnitude as the measurement accuracy of the pre-output flow controller, specifically, it should not exceed three times the measurement accuracy of the pre-output flow controller.

[0030] Furthermore, the length of the first output tube ensures that when the operation logic instruction for the first classification is obtained, the heavy water corresponding to the analysis result of the first analysis has not yet obtained a clear classification flow direction, thus ensuring that the high-grade heavy water storage tank will not be contaminated by low-grade heavy water due to the delay in analysis results. The low-grade heavy water refers to the heavy water with unqualified conductivity.

[0031] further,

[0032] The heavy water concentration online analysis unit is used to perform a second analysis on the heavy water that has passed the first analysis, and to perform a second classification of the heavy water, distributing the heavy water to the intermediate heavy water storage tank or the high-grade heavy water storage tank; the second analysis refers to the heavy water concentration analysis.

[0033] The heavy water whose concentration analysis results reach the preset heavy water concentration limit is automatically transported to the advanced heavy water storage tank by the valve assembly that connects the path to the advanced heavy water storage tank through the control terminal; at the same time, the liquid storage in the advanced heavy water storage tank is determined by associating and accumulating the delivery flow of the pre-purification unit, that is, the heavy water flow through the pre-output flow controller.

[0034] If the heavy water concentration analysis results do not meet the preset heavy water concentration limit, the valve assembly that opens the path to the intermediate heavy water storage tank through the control terminal will automatically transport the heavy water to the intermediate heavy water storage tank for temporary storage, pending subsequent processing and disposal. At the same time, the liquid storage volume in the intermediate heavy water storage tank will be determined by associating and accumulating the delivery flow of the pre-purification unit, that is, the heavy water flow through the pre-output flow controller.

[0035] Furthermore, the length of the second output tube ensures that when the operation logic instruction for the second classification is obtained, the heavy water corresponding to the analysis result of the second analysis has not yet obtained a clear classification flow direction, thus ensuring that the high-grade heavy water storage tank will not be contaminated by low-grade heavy water due to the delay in analysis results. The low-grade heavy water refers to heavy water whose analysis result of the heavy water concentration analysis does not meet the preset heavy water concentration limit.

[0036] The beneficial effects of this invention are as follows:

[0037] 1. By using a series of online analytical measurement devices (including an electromagnetic flowmeter 3 and an infrared spectrometer 4) and pipeline switching devices (i.e., valve assemblies), the direction of heavy water is automatically adjusted according to the relevant measurement results, thereby realizing automatic water quality detection and graded storage of heavy water.

[0038] 2. Utilizing the working principle of the electromagnetic flowmeter 3, the conductivity monitoring and flow monitoring functions are innovatively integrated into one, eliminating the need for a separate conductivity meter, reducing usage costs, and facilitating installation.

[0039] 3. The system's operating status is linked to the delivery of heavy water (pre-stage liquid) to the upstream purification unit 1, thereby improving the effectiveness of the system's operation.

[0040] 4. The pipeline design of the third pipeline 10, the fifth pipeline 12 and the sixth pipeline 13 allows for analysis feedback time (that is, allows for sufficient pipeline length), making hierarchical control more precise. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of a heavy water quality monitoring and graded storage system according to a specific embodiment of the present invention;

[0042] In the diagram: 1-Pre-treatment unit, 2-Pre-treatment output flow controller, 3-Electromagnetic flow meter, 4-Infrared spectrometer, 5-Low-grade heavy water storage tank, 6-Medium-grade heavy water storage tank, 7-High-grade heavy water storage tank, 8-First pipeline, 9-Second pipeline, 10-Third pipeline, 11-Fourth pipeline, 12-Fifth pipeline, 13-Sixth pipeline, 14-First output pipe, 15-First outlet, 16-Second output pipe, 17-Second outlet. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] This invention provides a heavy water quality monitoring and graded storage system (see...) Figure 1 This device is used to monitor and classify the heavy water after it has been upgraded by the pre-purification unit 1. It includes a conductivity and flow monitoring unit and a heavy water concentration online analysis unit connected through a third pipeline 10. The conductivity and flow monitoring unit is connected to the downstream end of the pre-purification unit 1 through the third pipeline 10. It also includes a heavy water storage system connected to the conductivity and flow monitoring unit and the heavy water concentration online analysis unit.

[0045] The heavy water storage system includes a low-grade heavy water storage tank 5, a medium-grade heavy water storage tank 6, and a high-grade heavy water storage tank 7;

[0046] It also includes a first pipeline 8, the top end of which is connected to the pre-purification unit 1, and the tail end of which is connected to the conductivity and flow monitoring unit.

[0047] It also includes a fourth pipeline 11, the top end of which is connected to the rear end of the conductivity and flow monitoring unit, and the tail end of which is connected to the low-grade heavy water storage tank 5.

[0048] The conductivity and flow monitoring unit is provided with a first output tube 14 at the rear end. The top end of the first output tube 14 is connected to the rear end of the conductivity and flow monitoring unit. The tail end of the first output tube 14 serves as the first outlet 15. The top ends of the third pipeline 10 and the fourth pipeline 11 converge at the first outlet 15 and are connected to the conductivity and flow monitoring unit through the first output tube 14.

[0049] It also includes a fifth pipeline 12, the top end of which is connected to the back end of the heavy water concentration online analysis unit, and the tail end of which is connected to the advanced heavy water storage tank 7.

[0050] It also includes a sixth pipeline 13, the top end of which is connected to the back end of the heavy water concentration online analysis unit, and the tail end of which is connected to the intermediate heavy water storage tank 6.

[0051] The heavy water concentration online analysis unit is provided with a second output pipe 16 at the rear end. The top end of the second output pipe 16 is connected to the rear end of the heavy water concentration online analysis unit, and the tail end of the second output pipe 16 serves as the second outlet 17. The top ends of the fifth pipeline 12 and the sixth pipeline 13 converge at the second outlet 17 and are connected to the heavy water concentration online analysis unit through the second output pipe 16.

[0052] Pipelines 8, 10, 11, 12, and 13 (all buffer and analysis pipelines) are controlled by valve assemblies with communication capabilities, such as solenoid valves, to achieve automatic switching of the heavy water pipeline flow path. Flow meters and pressure gauges are installed on pipelines 8, 10, 11, 12, and 13 to measure the flow rate and pressure of heavy water at corresponding locations, meeting the heavy water flow rate and pressure monitoring requirements at relevant points along the entire analysis and storage path involved in the process. Maintenance valves and bypasses are installed at both ends of the conductivity and flow monitoring unit and the online heavy water concentration analysis unit to facilitate maintenance and component replacement.

[0053] It also includes a control terminal, which is used to control the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly. The monitoring variable values, analysis results, and control signals of the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly are all transmitted to the control terminal via PLC. The control terminal is responsible for signal parsing, value comparison, classification judgment, component control, and cumulative calculation, and comprehensively regulates the flow status of each pipeline so that heavy water of the corresponding heavy water concentration flows into the corresponding level of heavy water storage tank for subsequent treatment and utilization.

[0054] The conductivity and flow rate monitoring unit is used to perform the first analysis and the first classification of heavy water.

[0055] The first classification includes transporting heavy water that passes the first analysis to the online heavy water concentration analysis unit for a second analysis, and transporting heavy water that fails the first analysis to the low-grade heavy water storage tank 5 for storage.

[0056] The first analysis refers to monitoring the conductivity of the heavy water after the upgrade treatment of the pre-purification unit 1 (monitoring the electrolyte content in the upgraded heavy water). If the conductivity of the heavy water is qualified, the result of the first analysis is qualified; otherwise, the result of the first analysis is unqualified.

[0057] The conductivity and flow monitoring unit includes a pre-stage output flow controller 2 and an electromagnetic flow meter 3 connected in series via a second pipeline 9. The pre-stage output flow controller 2 is located near the downstream end of the pre-stage purification unit 1.

[0058] The pre-stage output flow controller 2 is used for the interlocking start of the heavy water quality monitoring and tiered storage system (i.e., this system). The heavy water quality monitoring and tiered storage system can only be interlocked and started when the heavy water delivered by the pre-stage purification unit 1 meets the set flow limit. The monitored heavy water originates from the pre-stage purification unit 1, therefore the operating status of this system must be correlated with the effective operating status of the pre-stage purification unit 1. The design correlates the system's activation status with the liquid flow rate in the interface pipeline of the pre-stage purification unit 1: the system can only be interlocked and started when the liquid delivered by the pre-stage purification unit 1 meets a certain flow limit; otherwise, it indicates that the pre-stage purification unit 1 has no heavy water output, and this system enters a dormant state. In the dormant state, the system's main logic control program stops collecting data from relevant analysis equipment and performing logical comparison and tiering operations.

[0059] Electromagnetic flowmeter 3 is used to monitor the flow rate of heavy water passing through the conductivity and flow monitoring unit and the subsequent online heavy water concentration analysis unit. It is also used in the initial analysis to determine if the conductivity of the heavy water is within acceptable limits. Electromagnetic flowmeter 3 utilizes the principle of electromagnetic induction, measuring the flow rate of conductive fluid based on the electromotive force induced when the conductive fluid cuts magnetic field lines as it passes through an applied magnetic field. Therefore, electromagnetic flowmeter 3 has specific requirements regarding the conductivity of the measured liquid. When the conductivity of the flowing liquid is too low, it is difficult to effectively detect the induced electromotive force. Generally, electromagnetic flowmeter 3 has a lower limit requirement for the conductivity of the measured medium. When the fluid conductivity is lower than the lower limit requirement for the conductivity of the measured medium, the electromagnetic flowmeter... 3. The reading will decrease and become unstable; this invention utilizes the characteristic that the electromagnetic flowmeter 3 cannot work properly and will produce reading errors when encountering fluids with low conductivity. By monitoring the stability of the reading of the electromagnetic flowmeter 3, the conductivity range of the flowing heavy water can be determined. It innovatively integrates conductivity monitoring and flow monitoring functions into one. By monitoring the stability of the reading of the electromagnetic flowmeter 3, the difference in the flow rate delivered to the system by the upstream purification unit 1 is simultaneously compared to determine the conductivity change of the heavy water flowing through it, and the first classification is performed based on this. Compared with the traditional electromagnetic flowmeter + conductivity meter solution, the installation of the conductivity meter is eliminated, reducing the cost of use and facilitating installation.

[0060] The first classification includes the following two situations:

[0061] In the first scenario, if the reading of the electromagnetic flowmeter 3 is consistent with the delivery flow of the upstream purification unit 1 (i.e., the reading of the upstream output flow controller 2) and remains stable, then the conductivity of the heavy water is unqualified. The control terminal will automatically connect the valve assembly of the pipeline path to the low-level heavy water storage tank 5 to transport the heavy water with unqualified conductivity to the low-level heavy water storage tank 5 for temporary storage, pending subsequent processing and disposal. At the same time, by connecting and accumulating the delivery flow of the upstream purification unit 1 (i.e., the heavy water flow through the upstream output flow controller 2), the liquid storage in the low-level heavy water storage tank 5 is determined.

[0062] The second scenario is that if the reading of the electromagnetic flowmeter 3 fluctuates abnormally, and the delivery flow of the pre-purification unit 1 (i.e., the reading of the pre-output flow controller 2) is stable, then the conductivity of the heavy water is qualified. The control terminal will automatically associate the valve assembly that opens the path to the online heavy water concentration analysis unit, and deliver the qualified heavy water to the online heavy water concentration analysis unit for further analysis.

[0063] Simultaneously, the heavy water pressure at corresponding points on the pipeline (including the analysis and storage paths in the process) is monitored using pressure gauges.

[0064] In the first scenario, the criterion for judging whether the reading of the electromagnetic flowmeter 3 is consistent and stable with the reading of the upstream output flow controller 2 is jointly determined by the measurement accuracy of the electromagnetic flowmeter 3 and the measurement accuracy of the upstream output flow controller 2. When the reading of the electromagnetic flowmeter 3 is consistent and stable with the reading of the upstream output flow controller 2, the difference between the reading of the electromagnetic flowmeter 3 and the reading of the upstream output flow controller 2 shall not exceed 5 times the measurement accuracy of the larger of the two, and the fluctuation of the reading of the electromagnetic flowmeter 3 should be within the same order of magnitude as the measurement accuracy of the electromagnetic flowmeter 3, specifically not exceeding 3 times the measurement accuracy of the electromagnetic flowmeter 3.

[0065] In the second scenario, abnormal fluctuation in the reading of electromagnetic flowmeter 3 refers to the difference (absolute value) between the reading of electromagnetic flowmeter 3 and the reading of the upstream output flow controller 2 being no less than 30 times the measurement accuracy of electromagnetic flowmeter 3. Specifically, abnormal fluctuation in the reading of electromagnetic flowmeter 3 can be determined as follows: the reading of electromagnetic flowmeter 3 drops to less than half of the reading of the upstream output flow controller 2, and fluctuates significantly around a certain low flow value, with the fluctuation amplitude exceeding 50% of the average flow rate within the fluctuation period. For example: electromagnetic flowmeter accuracy: 1%FS, upstream purification unit 1 delivery flow rate: 100L / min, electromagnetic flowmeter reading: 30±20L / min. This situation constitutes abnormal reading fluctuation.

[0066] In the second case, the criterion for judging the stability of the delivery flow of the pre-stage purification unit 1 is determined by the measurement accuracy of the pre-stage output flow controller 2. When the delivery flow of the pre-stage purification unit 1 is stable, the fluctuation of the reading of the pre-stage output flow controller 2 should be on the same order of magnitude as the measurement accuracy of the pre-stage output flow controller 2, specifically, it should not exceed 3 times the measurement accuracy of the pre-stage output flow controller 2.

[0067] Based on the system design flow rate, analysis feedback time, and pipeline diameter, the first output pipe 14 needs to be reserved with sufficient length. The length of the first output pipe 14 is sufficient to ensure that when the operation logic command for the first classification is obtained, the actual heavy water corresponding to the analysis result of the first analysis (the monitoring result of the conductivity of heavy water) has not yet obtained a clear classification flow direction (that is, it has not yet been allocated to a specific level of heavy water storage tank). This ensures that the high-grade heavy water storage tank 7 will not be contaminated by low-grade heavy water due to the delay in analysis results. Low-grade heavy water refers to heavy water with unqualified conductivity.

[0068] The heavy water concentration online analysis unit is used to perform a second analysis on heavy water that has passed the first analysis (i.e., has qualified conductivity), and to perform a second classification of the heavy water, distributing it to the intermediate heavy water storage tank 6 or the high-grade heavy water storage tank 7; the second analysis refers to the heavy water concentration analysis.

[0069] Heavy water whose concentration analysis results reach the preset heavy water concentration limit is automatically transported to the advanced heavy water storage tank 7 by the valve assembly that opens the path through the control terminal; at the same time, the liquid storage in the advanced heavy water storage tank 7 is determined by associating and accumulating the delivery flow of the pre-purification unit 1, that is, the heavy water flow through the pre-output flow controller 2.

[0070] If the heavy water concentration analysis results do not meet the preset heavy water concentration limit, the valve assembly that automatically connects to the path to the intermediate heavy water storage tank 6 through the control terminal will transport the heavy water to the intermediate heavy water storage tank 6 for temporary storage, pending subsequent processing and disposal. At the same time, the liquid storage in the intermediate heavy water storage tank 6 will be determined by associating and accumulating the delivery flow of the upstream purification unit 1, that is, the heavy water flow through the upstream output flow controller 2.

[0071] Due to the working principle and calculation requirements of the equipment, the real-time analysis results provided by the online analysis equipment are delayed and do not match the actual flowing fluid in time and space. Therefore, similarly, the second output pipe 16 located at the rear end of the heavy water concentration online analysis unit and before the heavy water storage system also needs to be of sufficient length. The length of the second output pipe 16 can ensure that when the operation logic command for the second classification is obtained, the actual heavy water corresponding to the analysis result of the second analysis (the analysis result of the heavy water concentration analysis) has not yet obtained a clear classification flow direction (that is, it has not yet been allocated to a specific level of heavy water storage tank), ensuring that the high-grade heavy water storage tank 7 will not be contaminated by low-grade heavy water due to the delay in analysis results. Low-grade heavy water refers to heavy water whose analysis result of the heavy water concentration analysis does not meet the preset heavy water concentration limit.

[0072] The device described in this invention is not limited to the embodiments described in the specific implementation. Other implementation methods derived by those skilled in the art based on the technical solution of this invention also fall within the scope of technical innovation of this invention.

Claims

1. A heavy water quality monitoring and graded storage system, used for monitoring and grading heavy water after upgrading treatment by a pre-purification unit (1), characterized in that: It includes a conductivity and flow monitoring unit and a heavy water concentration online analysis unit connected through a third pipeline (10). The conductivity and flow monitoring unit is connected to the downstream end of the pre-purification unit (1). It also includes a heavy water storage system connected to the conductivity and flow monitoring unit and the heavy water concentration online analysis unit. The heavy water storage system includes a low-level heavy water storage tank (5), a medium-level heavy water storage tank (6), and a high-level heavy water storage tank (7). It also includes a first pipeline (8), the top end of which is connected to the pre-purification unit (1), and the tail end of which is connected to the conductivity and flow monitoring unit. It also includes a fourth pipeline (11), the top end of which is connected to the rear end of the conductivity and flow monitoring unit, and the tail end of which is connected to the low-grade heavy water storage tank (5). The conductivity and flow monitoring unit is provided with a first output tube (14) at the rear end. The top end of the first output tube (14) is connected to the rear end of the conductivity and flow monitoring unit. The tail end of the first output tube (14) serves as the first outlet (15). The top ends of the third pipeline (10) and the fourth pipeline (11) converge at the first outlet (15) and are connected to the conductivity and flow monitoring unit through the first output tube (14). It also includes a fifth pipeline (12), the top end of which is connected to the back end of the heavy water concentration online analysis unit, and the tail end of which is connected to the high-grade heavy water storage tank (7). It also includes a sixth pipeline (13), the top end of which is connected to the back end of the heavy water concentration online analysis unit, and the tail end of which is connected to the intermediate heavy water storage tank (6). The heavy water concentration online analysis unit is provided with a second output pipe (16) at the rear end. The top end of the second output pipe (16) is connected to the rear end of the heavy water concentration online analysis unit, and the tail end of the second output pipe (16) serves as the second outlet (17). The top ends of the fifth pipeline (12) and the sixth pipeline (13) converge at the second outlet (17) and are connected to the heavy water concentration online analysis unit through the second output pipe (16).

2. The heavy water quality monitoring and graded storage system as described in claim 1, characterized in that: The first pipeline (8), the third pipeline (10), the fourth pipeline (11), the fifth pipeline (12), and the sixth pipeline (13) are all controlled by valve assemblies with communication operation capabilities; the first pipeline (8), the third pipeline (10), the fourth pipeline (11), the fifth pipeline (12), and the sixth pipeline (13) are all equipped with flow meters and pressure gauges to measure the flow rate and pressure of heavy water at the corresponding locations; valves and bypasses for maintenance are installed at both ends of the conductivity and flow monitoring unit and the heavy water concentration online analysis unit to facilitate maintenance and component replacement.

3. The heavy water quality monitoring and graded storage system as described in claim 2, characterized in that: It also includes a control terminal, which is used to control the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly. The monitoring variable values, analysis results, and control signals of the conductivity and flow monitoring unit, the heavy water concentration online analysis unit, and the valve assembly are all transmitted to the control terminal via a PLC. The control terminal is responsible for signal parsing, value comparison, classification judgment, component control, and cumulative calculation, and comprehensively regulates the flow status of each pipeline so that the heavy water of the corresponding heavy water concentration flows into the corresponding level of heavy water storage tank.

4. The heavy water quality monitoring and graded storage system as described in claim 3, characterized in that: The conductivity and flow rate monitoring unit is used to perform the first analysis of the heavy water and the first classification of the heavy water; The first classification includes transporting the heavy water that passes the first analysis to the online heavy water concentration analysis unit for a second analysis, and transporting the heavy water that fails the first analysis to the low-grade heavy water storage tank (5) for storage. The first analysis refers to monitoring the conductivity of the heavy water after the upgraded treatment by the pre-purification unit (1). If the conductivity of the heavy water is qualified, the result of the first analysis is qualified; otherwise, the result of the first analysis is unqualified.

5. The heavy water quality monitoring and graded storage system as described in claim 4, characterized in that: The conductivity and flow monitoring unit includes a pre-stage output flow controller (2) and an electromagnetic flow meter (3) connected in series via a second pipeline (9). The pre-stage output flow controller (2) is located near the downstream end of the pre-stage purification unit (1). The pre-stage output flow controller (2) is used to interlock the start of the heavy water quality monitoring and graded storage system. The heavy water quality monitoring and graded storage system can only be interlocked when the heavy water delivered by the pre-stage purification unit (1) meets the set flow limit. The electromagnetic flowmeter (3) is used to monitor the flow rate of the heavy water and is also used in the first analysis to determine whether the conductivity of the heavy water is qualified.

6. The heavy water quality monitoring and graded storage system as described in claim 5, characterized in that, The first classification includes the following two situations: In the first case, if the reading of the electromagnetic flowmeter (3) is consistent with the delivery flow of the pre-purification unit (1), i.e. the reading of the pre-output flow controller (2), and remains stable, then the conductivity of the heavy water is unqualified. The control terminal will automatically connect the valve assembly of the pipeline path to the low-level heavy water storage tank (5) to transport the heavy water with unqualified conductivity to the low-level heavy water storage tank (5) for temporary storage, pending subsequent processing and disposal. At the same time, by connecting and accumulating the delivery flow of the pre-purification unit (1), i.e. the heavy water flow through the pre-output flow controller (2), the liquid storage in the low-level heavy water storage tank (5) will be determined. The second scenario is that if the reading of the electromagnetic flowmeter (3) fluctuates abnormally, and the delivery flow of the pre-purification unit (1), i.e. the reading of the pre-output flow controller (2), is stable, then the conductivity of the heavy water is qualified. The control terminal will automatically associate and open the valve assembly of the path to the online heavy water concentration analysis unit, and deliver the heavy water with qualified conductivity to the online heavy water concentration analysis unit for further analysis. Simultaneously, the pressure of heavy water at corresponding points on the pipeline is monitored using the pressure gauge; In the first case, the criterion for judging whether the reading of the electromagnetic flowmeter (3) is consistent and stable with the reading of the upstream output flow controller (2) is jointly determined by the measurement accuracy of the electromagnetic flowmeter (3) and the measurement accuracy of the upstream output flow controller (2). When the reading of the electromagnetic flowmeter (3) is consistent and stable with the reading of the upstream output flow controller (2), the difference between the reading of the electromagnetic flowmeter (3) and the reading of the upstream output flow controller (2) is not higher than 5 times the measurement accuracy of the larger of the measurement accuracy of the electromagnetic flowmeter (3) and the upstream output flow controller (2). Moreover, the fluctuation of the reading of the electromagnetic flowmeter (3) should be on the same order of magnitude as the measurement accuracy of the electromagnetic flowmeter (3), specifically, it should not exceed 3 times the measurement accuracy of the electromagnetic flowmeter (3). In the second case, the abnormal fluctuation of the reading of the electromagnetic flowmeter (3) means that the difference between the reading of the electromagnetic flowmeter (3) and the reading of the upstream output flow controller (2) is not less than 30 times the measurement accuracy of the electromagnetic flowmeter (3). In the second case, the criterion for judging the stability of the delivery flow of the pre-purification unit (1) is determined by the measurement accuracy of the pre-output flow controller (2). When the delivery flow of the pre-purification unit (1) is stable, the fluctuation of the reading of the pre-output flow controller (2) should be on the same order of magnitude as the measurement accuracy of the pre-output flow controller (2), specifically, it should not exceed 3 times the measurement accuracy of the pre-output flow controller (2).

7. The heavy water quality monitoring and graded storage system as described in claim 6, characterized in that: The length of the first output tube (14) is sufficient to ensure that when the first classification operation logic instruction is obtained, the heavy water corresponding to the analysis result of the first analysis has not yet obtained a clear classification flow direction, thus ensuring that the high-grade heavy water storage tank (7) will not be contaminated by low-grade heavy water due to the delay in analysis results. The low-grade heavy water refers to the heavy water with unqualified conductivity.

8. The heavy water quality monitoring and graded storage system as described in claim 7, characterized in that: The heavy water concentration online analysis unit is used to perform a second analysis on the heavy water that has passed the first analysis, and to perform a second classification on the heavy water, distributing the heavy water to the intermediate heavy water storage tank (6) or the advanced heavy water storage tank (7); the second analysis refers to the heavy water concentration analysis; The heavy water whose concentration analysis results reach the preset heavy water concentration limit is automatically connected to the valve assembly of the path to the advanced heavy water storage tank (7) through the control terminal and transported to the advanced heavy water storage tank (7) for storage; at the same time, the liquid storage in the advanced heavy water storage tank (7) is determined by associating and accumulating the delivery flow of the pre-purification unit (1), that is, the heavy water flow through the pre-output flow controller (2); If the heavy water concentration analysis result does not meet the preset heavy water concentration limit, the valve assembly that opens the path to the intermediate heavy water storage tank (6) through the control terminal will automatically transport it to the intermediate heavy water storage tank (6) for temporary storage, pending subsequent processing and disposal; at the same time, by associating and accumulating the delivery flow of the pre-purification unit (1), that is, the heavy water flow through the pre-output flow controller (2), the liquid storage in the intermediate heavy water storage tank (6) will be determined.

9. The heavy water quality monitoring and graded storage system as described in claim 8, characterized in that: The length of the second output tube (16) is sufficient to ensure that when the second classification operation logic instruction is obtained, the heavy water corresponding to the analysis result of the second analysis has not yet obtained a clear classification flow direction, thus ensuring that the high-grade heavy water storage tank (7) will not be contaminated by low-grade heavy water due to the delay in the analysis result. The low-grade heavy water refers to the heavy water whose analysis result of the heavy water concentration analysis does not meet the preset heavy water concentration limit.

Images