Method for automatically testing availability of control rod drop function and DCS system

Abstract

A method for automatically testing the availability of a control rod drop function and a DCS system. The method comprises: receiving a test start instruction to enter a test mode and, in the test mode, acquire the sequence of testing test rod groups, and measurement rod positions and count rod positions of control rods (S1); sending a rod moving instruction to the current test rod group (S21); after the control rods of the current test rod group have moved, a count rod position being consistent with a target rod position, and measuring a change quantity of the measurement rod position of the control rods (S22); determining whether the change quantity of the measurement rod position of the control rods meets a preset threshold (S23); and, if so, determining that the availability test of the control rod drop function of the current test rod group has passed (S24).

Description

An automated testing method and DCS system for the usability of control rod dropping function Technical Field

[0001] This invention relates to the field of automation, and more particularly to an automated testing method and DCS system for the usability of a control rod dropping function. Background Technology

[0002] The nuclear power unit requires monthly control rod drop capability tests to check that the control rods operate normally without jamming, ensuring that they can drop and shut down the reactor upon receiving a shutdown signal. Due to production management needs, these tests are always scheduled for the night shift. The tests involve reactive changes, requiring operators to maintain continuous focus, and the shift supervisor must monitor the entire process. If the test exceeds four hours, there is a risk of human error and serious consequences. The shift supervisor and primary circuit operator's prolonged focus on this test disrupts overall unit monitoring.

[0003] The complex interface, tedious operation, and long workload place psychological and physiological stress on operators, making them highly susceptible to human error. Furthermore, prolonged focus on the experiment reduces the monitoring of other equipment within the unit. All of these factors are detrimental to the safe and stable operation of the nuclear power plant unit.

[0004] For example, during the test, the control rod will move in three steps, each step being 1 cm, with a change generally exceeding 2 cm. Compared to the 416 cm range, this change is relatively small. During the verification of the test results, the operator needs to retrieve and amplify historical trends, measure and calculate with a ruler, and finally give a conclusion on whether the test is qualified (whether the change is greater than the 2 cm standard). This process is time-consuming and prone to errors. Summary of the Invention

[0005] The technical problem that this invention aims to solve is that operators frequently perform repetitive operations, which can easily lead to human error, and the verification of test results requires manual verification by operators, which is time-consuming and prone to errors.

[0006] The technical solution adopted by this invention to solve its technical problem is: an automated testing method for the availability of a control rod dropping function, applied to a DCS system, wherein the DCS system is communicatively connected to a rod control system, and the rod control system is used to manipulate the movement of the control rod according to instructions, including:

[0007] S1. Receive the test start command, enter the test mode, and in the test mode, obtain the test sequence of each test rod group, the measuring rod position and the counting rod position of the control rod in the test rod group;

[0008] S2. Following the test sequence, by sending instructions to the rod control system, each test rod group is tested sequentially in the following manner:

[0009] S21. Send the rod-moving command to the current test rod group;

[0010] S22. After the control rod of the current test rod group completes its action, the change in the measuring rod position of the control rod is detected;

[0011] S23. Determine whether the change in the position of the measuring rod meets a preset threshold.

[0012] S24. If so, the usability test of the control rod dropping function of the current test rod group is deemed qualified.

[0013] Preferably, S21 includes:

[0014] S211. Send a selection command to the rod control system, the selection command being used to select the current test rod group participating in the test;

[0015] S212. Detect the measuring rod position and counting rod position of the control rod in the current test rod group, set the target rod position, and determine whether the deviation between the counting rod position and the target rod position meets the preset threshold.

[0016] S213. If so, the target rod position is set correctly, and the rod control system sends the rod movement command for the current test rod group.

[0017] Preferably, after S211, the method further includes:

[0018] S214. Determine whether the selected instruction is effective. If so, execute S212.

[0019] Preferably, determining whether the selection command is effective includes: after sending the selection command to the rod control system, if a feedback signal is received from the rod control system, then the selection command is determined to be effective.

[0020] Preferably, the process after S24 includes:

[0021] S25. End the test of the current test rod group and deselect the current test rod group;

[0022] S26. Determine whether all test bar groups have completed the test. If not, send a selection command to the next test bar group according to the test order.

[0023] Preferably, the process further includes the following steps before step S1:

[0024] S3. Send a speed setting command to the rod control system so that the rod control system sets the displacement speed of the control rod in the test mode;

[0025] S4. Control the control rods to enter the sub-rod group mode, wherein the sub-rod group mode is a preset arrangement of control rods in the nuclear reactor.

[0026] Preferably, it further includes: continuously monitoring the reactor status to determine whether the preset test conditions are met; if not, outputting an alarm signal and terminating the test.

[0027] Preferably, the monitoring of reactor status includes: monitoring the core's linear power density, axial power distribution, radial power distribution, DNBR margin, control rod insertion limit, average temperature limit, load shedding, reactor shutdown, and secondary loop alarms.

[0028] Preferably, it further includes: monitoring the action response time of the control rod of the test rod group after receiving the moving rod command, and outputting an alarm if the time exceeds a preset time threshold.

[0029] The present invention also provides a DCS system, including a processor and a memory storing a computer program, wherein the processor, when executing the computer program, implements an automated testing method for the availability of any of the above-mentioned control rod dropping functions.

[0030] The technical solution of this invention has the following beneficial effects: 1. It transforms the control rod drop function availability test from traditional manual operation to automated test, reducing human error and effectively avoiding various losses caused by human error; 2. It shortens the time spent on the entire test, saves a lot of manpower, and improves the efficiency of test execution; 3. It automatically gives the test results through signal acquisition and automatic calculation, so as to avoid the long time for manual verification and the easy occurrence of human error.

[0031] Furthermore, to prevent potential logical anomalies during automated testing, this invention separates rod speed settings and sub-rod group modes from the overall testing logic. It also includes an anomaly alarm and braking logic to promptly alert operators for manual intervention upon the occurrence of an anomaly alarm. Implementing this invention automates the entire testing process, automatically halting the test upon an anomaly without requiring manual intervention. This automated testing method frees operators from tedious tasks, allowing them to focus more on overall test control and monitoring in the control room. Attached Figure Description

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0033] Figure 1 is a diagram of the operation interface of the control rod dropping function availability test system of the present invention.

[0034] Figure 2 is a schematic diagram showing the verification of the test results of the control rod dropping function of the present invention;

[0035] Figure 3 is a logic block diagram of an embodiment of an automated testing method for the availability of a control rod dropping function according to the present invention.

[0036] Figure 4 is a logic block diagram of an embodiment of an automated testing method for the availability of a control rod dropping function according to the present invention.

[0037] Figure 5 is a structural diagram of an embodiment of an automated testing system for the availability of a control rod dropping function. Detailed Implementation

[0038] To provide a clearer understanding of the technical features, objectives, and effects of this invention, specific embodiments are now described in detail with reference to the accompanying drawings. Those skilled in the art can understand the specific meaning of the terms used in this invention based on the specific circumstances.

[0039] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the invention. However, those skilled in the art will understand that the invention can be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods are omitted so as not to obscure the description of the invention with unnecessary detail.

[0040] A nuclear power unit in my country requires monthly availability tests for the control rod drop function, currently performed manually by operators. The operating interface is shown in Figure 1. In Figure 1, the horizontal axis is A~T, and the vertical axis is 1~17, representing the positions of 89 control rod bundles in the reactor core. The 89 control rod groups are grouped as shown in Table 1: the control rods are divided into N01~N13, PA to ~PI, and the central rod (see the first column). For example, the first row, group N01, belongs to the N2 shutdown rods and is controlled by the RodPilot control cabinet in section 3. It includes rod 01 in section 1, rod 26 in section 2, rod 51 in section 3, and rod 76 in section 4. Rod 01 is located at coordinate R15 in the core, rod 26 at coordinate R03, rod 51 at coordinate C03, and rod 76 at coordinate C15.

[0041]

[0042] Table 1: Control Rod Grouping Table

[0043] Availability testing is a periodic test of the control rod drop function that nuclear power units need to perform. Its purpose is to check that the control rods are operating normally and without jamming, so as to ensure that the control rods can drop to achieve the shutdown function after a shutdown signal is issued.

[0044] In the existing technology, the operator needs to perform the following 46 (23 groups of rods, lifting and inserting once each) operations on each of the 23 sub-bar groups and verify the test results.

[0045] The complex interface, tedious operation, and long workload place psychological and physiological stress on operators, making them highly susceptible to human error. Furthermore, prolonged focus on the experiment reduces the monitoring of other equipment within the unit. All of these factors are detrimental to the safe and stable operation of the nuclear power plant unit.

[0046] For example, during the test, the control rod will move in 3 steps, correspondingly, the counting rod position will change in 3 steps, and the measurement rod position will change by 2 cm or more. For each displacement step, the control rod will move by 1 cm, and the total change of 2-3 cm over 3 steps is relatively small compared to the 416 cm measurement range. As shown in Figure 2, during the verification of the test results, the operator needs to retrieve and magnify historical trends, measure and calculate with a ruler, and finally give a conclusion on whether the test is qualified (whether the change is greater than the 2 cm standard). This process is time-consuming and prone to errors.

[0047] As shown in Figure 3, in the first embodiment of the automated testing method for the availability of control rod dropping function according to the present invention, an automated testing method for the availability of control rod dropping function is provided, applied to a DCS system. The DCS system is communicatively connected to the existing rod control system of the nuclear power plant, and the rod control system is used to control the movement of the control rod according to instructions. The automated testing method for the availability of control rod dropping function includes the following steps:

[0048] S1. Receive the test start command, enter the test mode, and in the test mode, acquire the test sequence of each test rod group, and the measurement rod position and counting rod position of the control rod in the test rod group. In this step, it should be noted that: after the DCS system receives the test start command, the test mode is triggered. The DCS system actively acquires the test sequence of each test rod group, and the current measurement rod position and counting rod position of each control rod in the test rod group, so as to generate the target rod position of each control rod during the test according to the test logic. The test sequence is the order in which all test rod groups participate in the test, automatically generated by the DCS system after grouping all control rods to be tested according to preset logic. The measurement rod position refers to the exact position of the control rod in the reactor core directly measured by physical sensors. The counting rod position refers to the number of control rod action steps; each action step of the control rod is counted once, and the accumulated number is called the counting rod position. The test rod group is obtained by grouping all control rods to be tested. Each test rod group contains several control rods. After the test mode is triggered, all control rods in the same test rod group participate in the test in the same batch.

[0049] In one specific embodiment, the control rod requires six steps: three steps of insertion and three steps of lifting, with each step involving a 1cm movement. During this process, the DCS system performs a check after each control rod movement to comprehensively determine whether the control rod's usability test is qualified. Implementing the technical solution of this embodiment allows the DCS system to automatically detect and judge, obtaining correct test results. Compared to traditional tests where operators must judge the control rod displacement of 2-3cm in each three steps within a total range of 416cm, requiring the operator to retrieve and amplify historical trends, measure and calculate with a ruler, and finally determine whether the test is qualified, this overcomes the drawbacks of easy judgment errors and time-consuming processes. By automatically acquiring signals and calculating results, the operator's attention is freed from tedious tasks, allowing them to focus more on monitoring the unit's status.

[0050] S2. Following the test sequence, by sending instructions to the rod control system, each test rod group is tested in the following manner:

[0051] S21. Send rod control commands to the current test rod group. In this step, it should be noted that the DCS system will send rod control commands to the rod group that needs to be tested for availability according to the pre-set test sequence. The commands include the target rod position and displacement speed of the control rod.

[0052] S22. After the control rod of the current test rod group completes its movement, the change in the measured position of the control rod is detected. It should be noted that the DCS system can monitor the position of the control rod and whether displacement has occurred. Therefore, the DCS system can monitor the movement state of the control rod and measure its position by observing the change in position before and after displacement.

[0053] S23. Determine whether the change in the position of the measuring rod meets the preset threshold. In this step, it should be noted that the DCS system can collect data from the displacement detector on the control rod, i.e., the measuring rod position signal. When the control rod moves to the correct position and the counting rod position and the target rod position are equal, determine whether the change in the measuring rod position meets the preset error threshold.

[0054] S24. If so, the usability test of the control rod dropping function of the current test rod group is deemed qualified.

[0055] If not, an alarm signal will be output, the test will be stopped, and staff will be notified to intervene. After the staff has handled the situation, they can choose whether to continue the test.

[0056] In an alternative embodiment, if not, the control bar is marked as failing the drop bar functionality availability test, and the control bar is skipped. After all test bar groups have been tested, a signal is output to remind the operator to intervene.

[0057] The technical solution implemented in this embodiment has the following beneficial effects: 1. It transforms the control rod drop function availability test from traditional manual operation to automated test, reducing human error and effectively avoiding various losses caused by human error; 2. It shortens the time spent on the entire test, saves a lot of manpower, and improves the efficiency of test execution; 3. It automatically gives the test results through signal acquisition and automatic calculation, avoiding the long time for manual verification and the ease with which human error occurs.

[0058] As shown in Figure 4, in another embodiment of the automated testing method for the availability of the control rod dropping function according to the present invention, S21 includes:

[0059] S211. Send a selection command to the rod control system. The selection command is used to select the current test rod group to participate in the test. In this step, it should be noted that only a limited number of control rods can be tested for availability each time. However, nuclear power plants have a large number of control rods. Considering the impact of a large number of control rod actions on core reactivity, it is not possible to put all control rods into availability testing at the same time. Therefore, after grouping the control rods, control commands need to be issued sequentially by group. When a test rod group is being tested, the other rod groups are in a waiting state. Therefore, a selection command needs to be sent to the current test rod group participating in the test. Test rod groups that are not selected are in a waiting state.

[0060] In an optional embodiment, S211 is followed by: S214, determining whether the selected command is effective; if so, then executing S212. In this step, it is important to note that the DCS system needs to determine whether the selected command is effective through feedback signals. If it is ineffective, an alarm signal is output, the test is stopped, and staff are alerted to intervene. After the staff has handled the situation, they can choose whether to continue the test. This avoids situations where the selected command is ineffective, causing the test rod group to fail to receive the rod-moving command sent by the DCS system through the rod control system, resulting in incomplete rod movement, but the system still judges the availability as normal. Implementing the technical solution of this embodiment can fill the logical loopholes in the DCS system's control rod dropping function availability test, ensuring that the control rod operation is performed as expected, and avoiding potential risks caused by non-execution of commands.

[0061] In an optional embodiment, determining whether the selection command is effective includes: after sending the selection command to the rod control system, if a feedback signal is received from the rod control system, then the selection command is determined to be effective. In this embodiment, the system confirms whether the selection command is effective by receiving the feedback signal from the rod control system. The presence of the feedback signal provides an additional checking mechanism, which helps to detect and prevent possible system failures or errors, thereby improving the reliability of the entire rod control system. It can reduce the need for operators to continuously monitor the system, as they can automatically confirm the success of the operation, thereby optimizing the operation process and improving efficiency.

[0062] S212. Detect the measuring rod position and counting rod position of the control rod in the current test rod group, set the target rod position, and determine whether the deviation between the counting rod position and the target rod position meets the preset threshold. In this step, it should be noted that the target rod position must be set according to the preset test logic and must have a certain deviation from the counting rod position; otherwise, the target rod position setting is unreasonable. In some embodiments, the target rod position is set to the counting rod position plus three or the counting rod position minus three. After the control rod is inserted or lifted three times, the counting rod position and the target rod position will be consistent.

[0063] S213. If so, the target rod position is set correctly, and the rod control system sends the rod movement command for the current test rod group.

[0064] The technical solution implemented in this embodiment can pre-confirm the selected state and target rod position setting, which can ensure that the execution of the control rod command is consistent with the operator's intention, reduce the risk of accidents caused by misoperation or setting errors, and help prevent power runaway or safety accidents caused by improper control rod position.

[0065] In one specific embodiment, S24 is followed by:

[0066] S25. End the test for the current test rod group and deselect the current test rod group. In this step, it should be noted that after the test of this group of control rods is completed, the DCS system stops all operations on that group of control rods, deselects it from the test status, removes the highlight or marker for the control rod group to indicate that it is no longer in an active test state, stops further movement of the control rods, records the current position and test data, and ensures that the control rods are in a safe position.

[0067] S26. Determine if all test rod groups have completed the test. If not, send a selection command to the next test rod group according to the test sequence. It's important to note in this step that after completing the current test rod group, it's necessary to check if all test rod groups have completed their tests. This process can be determined by checking the test progress and status records. After each test rod group completes its test, the DCS system will mark it as completed and record it when deselecting that test rod group, generating a test record for the DCS system and operators to query. If all test rod groups have completed the test, the entire test process ends, and the system automatically exits the test mode. If there are still incomplete test rod groups, the control system needs to select the next test rod group to be tested according to the predetermined test sequence.

[0068] Implementing the technical solution of this embodiment ensures that all test rod groups complete the control rod drop function availability test, which helps to ensure the safety and reliability of the reactor. By systematically testing each test rod group, operators can verify the function of the control rod drive mechanism, ensuring that they can accurately and reliably perform their functions when needed.

[0069] In one specific embodiment, the method further includes the following step before S1:

[0070] S3. Send a speed setting command to the rod control system to set the displacement speed of the control rod in test mode. It should be noted that before conducting the rod availability test, the rod's movement speed in test mode needs to be set to generate the rod movement command. This speed setting is to ensure smooth and controllable rod movement that meets the test requirements.

[0071] S4. The control rods are then moved into sub-rod group mode. Sub-rod group mode represents the preset arrangement of control rods in the nuclear reactor. It's important to note that sub-rod group mode is a specific control mode where control rods are controlled in experimental groups. Control rods within each group can move independently or collaboratively to achieve precise control of reactor power and reactivity. This mode allows for more granular and flexible adjustments to adapt to different operating conditions and control requirements.

[0072] The technical solution implemented in this embodiment ensures precise control of the control rods during the experiment, facilitating the evaluation and verification of the control rod system's responsiveness and reliability. It ensures the experiment is conducted under safe and controlled conditions while collecting valuable data to optimize reactor operation and control. It is important to note that to prevent abnormal activation of the test logic, rod speed settings, manual control rod mode, and control rod sub-group mode are not included in the test logic.

[0073] In one specific embodiment, the method further includes: continuously monitoring the reactor status to determine whether preset test conditions are met; if not, outputting an alarm signal and terminating the test. Monitoring the reactor status includes, but is not limited to: monitoring the core's linear power density, axial power distribution, radial power distribution, DNBR margin, control rod insertion limit, average temperature limit, load shedding, reactor shutdown, and secondary loop alarms. If the DCS system detects any alarm signal affecting the test, it immediately terminates the test and alerts personnel to intervene. After personnel eliminate the alarm signal interfering with the test, the operator can choose whether to continue the test.

[0074] In this embodiment, during the test, the DCS system also monitors some key signals within the reactor, such as line power density alarms, thermal power alarms, and control rod malfunctions. When an abnormal signal is detected, the braking logic automatically activates, halting the test and giving operators and maintenance personnel time to intervene. The test can resume after the anomaly is resolved. This automated braking logic reduces the risk of delayed reactions or incorrect decisions by operators in emergency situations, improving the reliability and stability of the entire DCS system.

[0075] In one specific embodiment, the DCS system also monitors the response time of the control rod in the test rod assembly after receiving the moving rod command. If the response time exceeds a preset time threshold, an alarm is output. In this embodiment, the response time refers to the time required for the control rod to move from a stationary state to a designated position after receiving the movement command. This time includes the system processing time, the start-up time of the mechanical components, the acceleration time, and the deceleration and stopping time. By implementing the technical solution of this embodiment, monitoring the response time of the control rod ensures that the control rod reaches the designated position within a predetermined time. If the response time is too long, an alarm signal can be output so that the operator can adjust and intervene in a timely manner, thereby enhancing the safety of the test process.

[0076] As shown in Figure 5, the present invention also constructs a DCS system, including a processor and a memory storing a computer program. When the processor executes the computer program, it implements the automated testing method for the availability of the control rod dropping function disclosed in any of the above embodiments.

[0077] Furthermore, the DCS system receives operator commands through its own user interface and transmits them to the rod control system via a gateway. The gateway has multiple Ethernet ports, supports various industrial communication protocols, and is responsible for protocol conversion and data routing, ensuring accurate data transmission between the DCS system and the rod control system. The rod control system feeds back the status information of the control rod to the DCS system, which then displays this information on the operator interface. Based on the automated usability testing method for the control rod dropping function disclosed in any of the above embodiments, the rod control system is controlled to perform usability testing on the control rod.

[0078] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly in hardware, software modules executed by a processor, or a combination of both. The DCS system can be housed in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0079] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. An automated testing method for the availability of a control rod dropping function, applied to a DCS system, wherein, The DCS system is communicatively connected to the rod control system, which is used to control the movement of the rod according to instructions. The system is characterized by comprising: S1. Receive the test start command, enter the test mode, and in the test mode, obtain the test sequence of each test rod group, the measuring rod position and the counting rod position of the control rod in the test rod group; S2. Following the test sequence, by sending instructions to the rod control system, each test rod group is tested sequentially in the following manner: S21. Send the rod-moving command to the current test rod group; S22. After the control rod of the current test rod group completes its action, the change in the measuring rod position of the control rod is detected; S23. Determine whether the change in the position of the measuring rod meets a preset threshold. S24. If so, the usability test of the control rod dropping function of the current test rod group is deemed qualified.

2. The automated testing method for the usability of the control rod dropping function according to claim 1, characterized in that, S21 includes: S211. Send a selection command to the rod control system, the selection command being used to select the current test rod group participating in the test; S212. Detect the measuring rod position and counting rod position of the control rod in the current test rod group, set the target rod position, and determine whether the deviation between the counting rod position and the target rod position meets the preset threshold. S213. If so, the target rod position is set correctly, and the rod control system sends the rod movement command for the current test rod group.

3. The automated testing method for the usability of the control rod dropping function according to claim 2, characterized in that, Following S211, the following is also included: S214. Determine whether the selected instruction is effective. If so, execute S212.

4. The automated testing method for the usability of the control rod dropping function according to claim 3, characterized in that, The step of determining whether the selection command is effective includes: after sending the selection command to the rod control system, if a feedback signal is received from the rod control system, then the selection command is determined to be effective.

5. The automated testing method for the usability of the control rod dropping function according to claim 2, characterized in that, S24 is followed by: S25. End the test of the current test rod group and deselect the current test rod group; S26. Determine whether all test bar groups have completed the test. If not, send a selection command to the next test bar group according to the test order.

6. The automated testing method for the usability of the control rod dropping function according to claim 1, characterized in that, Before S1, the following also applies: S3. Send a speed setting command to the rod control system so that the rod control system sets the displacement speed of the control rod in the test mode; S4. Control the control rods to enter the sub-rod group mode, wherein the sub-rod group mode is a preset arrangement of control rods in the nuclear reactor.

7. The automated testing method for the usability of the control rod dropping function according to claim 1, characterized in that, Also includes: The reactor status is continuously monitored to determine whether the preset test conditions are met. If not, an alarm signal is output and the test is terminated.

8. The automated testing method for the usability of the control rod dropping function according to claim 7, characterized in that, The monitored reactor status includes: monitoring the core's linear power density, axial power distribution, radial power distribution, DNBR margin, control rod insertion limit, average temperature limit, load shedding, reactor shutdown, and secondary loop alarms.

9. The automated testing method for the usability of the control rod dropping function according to claim 1, characterized in that, Also includes: The system monitors the response time of the control rod of the test rod group after receiving the command from the moving rod. If the response time exceeds a preset time threshold, an alarm is output.

10. A DCS system, comprising a processor and a memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the automated testing method for the availability of the control rod dropping function as described in any one of claims 1-9.

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