Automatic load-following simulation method based on mode-c control and operation mode

Abstract

An automatic load-following simulation method based on a Mode-C control and operation mode, for automatically controlling core reactivity and axial power deviation during boron-adjustment-free load following. The present application can achieve: automation of theoretical simulation of boron-adjustment-free load following, reduction of the workload of manual simulation, improvement of simulation accuracy and significant improvement of simulation efficiency, automatic optimization of initial rod positions and target axial power deviation settings, and improvement of rationality of simulation calculations.

Description

An Automatic Simulation Method for Load Tracking Based on Mode-C Control and Operation Mode Technical Field

[0001] This application belongs to the field of load tracking simulation technology, and in particular relates to an automatic load tracking simulation method based on Mode-C control and operation mode. Background Technology

[0002] Operating and control modes refer to the regulations and control methods used by a reactor to regulate the range of changes in parameters such as power level, axial deviation, and mean core coolant temperature under various permissible operating conditions, through the use of control rods, soluble boron, etc. Operating and control mode design technology is a mature technology abroad, such as the widely used Mode-A, Mode-G, and MSHIM modes.

[0003] Mode-A and Mode-G offer good base load operation capabilities, requiring only a small number of control rods (D / R) to be inserted into the core to meet normal operational needs. Compared to Mode-A, Mode-G offers enhanced load tracking capability. However, both modes require frequent boron adjustment operations during load tracking, leading to the following drawbacks: the generation of large amounts of radioactive waste, with boron adjustment at the end of the lifespan generating several times more waste than at the beginning; and the relatively frequent and manually performed boron adjustment operations increase the operator's workload. The MSHIM mode achieves load tracking operation without boron adjustment, offering good load tracking capability. However, during base load operation, a large number of control rods (array control rods from MA, MB, MC, and MD, and AO rod groups) are still inserted into the core, reducing some safety margins and causing certain hidden economic losses, such as control rod burnup losses and increased difficulty in rod removal operations at the end of the lifespan. The M rod group is a unique naming convention for the MSHIM mode, not used in other modes; the AO rod group description was first used in the MSHIM mode and is also referenced in the Mode-C mode.

[0004] In recent years, considering the operational characteristics of domestic pressurized water reactor nuclear power plants, which primarily operate under base load mode with relatively low demand for load tracking, the Mode-C operation and control mode design was first developed. This mode combines the strengths of various approaches: for the main operating mode (base load) within its lifespan, it maintains the most widely used control strategy, with mature operational and practical experience available for reference, which is conducive to the safe and economical operation of nuclear power plants. For operating modes with lower demand within their lifespan (such as load tracking and xenon oscillation), referencing the MSHIM mode, control rods are used instead of regulating soluble boron for core reactivity control. Reactivity and power distribution control are automatically completed through the rod control system, improving economic efficiency and significantly reducing the operator's workload.

[0005] The Mode-C operation and control mode features two independently controlled regulating rod groups: the T-rod group and the AO-rod group. The T-rod group moves according to a specified number of overlap steps and sequence; during load tracking, the insertion depth of the T-rod group into the core is determined by the total amount of various reactivity in the core, used to maintain core reactivity balance or to maintain the relationship between the reactor's average temperature and power according to a certain pattern. The AO-rod group generally inserts less into the core, operating only within a single operating zone at the top of the core; it is mainly used for axial power distribution control, keeping the core axial deviation within the target range.

[0006] In Mode-C operation and control mode, boron-free operation can be achieved during typical daily load tracking for at least 90% of the cycle length. To minimize human intervention during boron-free load tracking, theoretical simulations of boron-free load tracking are required beforehand. This involves determining how to rationally utilize core reactivity control methods, such as control rod assemblies and core feedback characteristics, without adjusting the core boron concentration during load tracking, so that the load tracking process follows a preset power-time curve and key core parameters such as core axial deviation are effectively controlled. Current technology only allows for manual simulation, which would involve a huge workload and very low simulation efficiency. Summary of the Invention

[0007] The purpose of this application is to provide an automatic load tracking simulation method based on Mode-C control and operation mode, which solves the problem of huge workload faced by manually simulating continuous load tracking across multiple time steps.

[0008] To achieve the above objectives, this application provides the following technical solution:

[0009] An automatic simulation method for load tracking based on Mode-C control and operation mode, which automatically controls core reactivity and axial power deviation during non-boron-adjusted load tracking process, includes:

[0010] Step 1: Read the input data and prepare the data;

[0011] Step 2: Based on the core power change and corresponding xenon reactivity effect at the current time step, perform automatic search for the bar adjustment criticality;

[0012] Step 3: Calculate the core axial power deviation ΔI and determine whether it is within the operating dead zone of the core axial power deviation ΔI. If so, exit the loop and proceed to the next time step simulation or terminate the process; otherwise, execute the automatic control of the operation belt and perform the core axial power deviation ΔI search calculation.

[0013] Step 4: Calculate the core Keff at the current control rod group position, and determine whether the core Keff meets the critical convergence criterion. If yes, exit the loop and proceed to the next time step simulation or end the simulation; otherwise, return to step 2.

[0014] Step 5: Automatically iterate until the critical convergence criterion is met, and control the core axial power deviation ΔI within the axial power deviation control dead zone;

[0015] If, after several iterations, the core axial power deviation ΔI still cannot be controlled within the axial power deviation control dead zone, determine whether the core axial power deviation ΔI is located in the operating zone. If not, report an error and exit; if so, further determine whether Keff has converged.

[0016] If Keff converges, the loop is exited and the time exceeding the axial power deviation control dead zone is recorded. If Keff does not converge, step 2 is returned and one round of steps 2 to 5 is executed.

[0017] If it is still not possible to simultaneously satisfy the conditions of control within the operating band and Keff convergence, an error will be reported and the process will exit.

[0018] Furthermore, in step 1, the input data includes: target axial power deviation, axial power deviation control dead zone and operating band, control rod group insertion / removal limits, initial control rod position, Keff convergence criterion, and T control rod group insertion sequence.

[0019] Further, in step 2, the core Keff at the current control rod group position is calculated to obtain the degree of deviation from the criticality and the direction of action of the T rod group. The critical rod position of the T rod group is obtained through the automatic search strategy for critical rod position.

[0020] Furthermore, the current control rod group position is either the initial rod position set in the simulation or the control rod position of the previous time step.

[0021] Furthermore, in step 3, when performing automatic control of core axial deviation, the core axial power deviation ΔI is controlled within the axial power deviation control dead zone by driving the AO rod group.

[0022] Furthermore, the automatic search for the initial rod position and target axial power deviation of the T-bar group, the automatic optimization of the Keff convergence criterion, and the automatic exchange of the T-bar group insertion order provide input for the core reactivity and axial power deviation in the automatic control of the boron-free load tracking process.

[0023] Furthermore, the T-bar groups are periodically switched between two T-bar group loading sequences: T1 to TN and TN to T1.

[0024] Furthermore, the cycle is set to 1000MWd / tU as the interval.

[0025] Furthermore, during the automatic control of core reactivity in the load tracking process, the critical rod position is obtained by searching according to the order of the inserted rods.

[0026] Furthermore, boron adjustment is performed before load tracking, and the T-bar group is inserted into the reactor core. Its initial bar position is inserted into the reactor core on the premise that the T-bar group can be smoothly returned to full power during the subsequent load tracking process.

[0027] Furthermore, by generating multiple insertion depth input schemes for simulation calculation, the scheme with the shallowest insertion depth is obtained among the schemes that achieve a 96-hour simulation.

[0028] Furthermore, during load tracking, a target axial power deviation ΔI is set. tar The AO rod assembly is used to automatically control the core axial power deviation ΔI.

[0029] Furthermore, the target axial power deviation ΔI is adjusted according to actual needs. tar The setting is relatively negative.

[0030] Furthermore, a more negative value would be -3% or -5%.

[0031] Furthermore, based on the target axial power deviation ΔItar value and the setting range and sampling interval of the initial rod position of the T-rod group, multiple schemes are formed for parallel calculation. Based on the calculation results, the simulation feasibility, the control of the core axial power deviation ΔI, and the operating range of the control rods are analyzed to obtain the initial rod position of the T-rod group and the target axial power deviation.

[0032] Furthermore, the automatic search for the initial rod position and target axial power deviation of the T-bar group includes the following steps:

[0033] Step 2.1: Input the target axial power deviation ΔItar value and the setting range and sampling interval of the initial rod position of the T-bar group;

[0034] Step 2.2: Generate n target axial power deviation ΔItar values ​​and m initial rod positions for T-bar groups, and combine them to form n×m sets of calculation inputs;

[0035] Step 2.3: Invoke the simulation computing module to perform calculations based on the parallel computing strategy;

[0036] Step 2.4: Analyze the calculation results to obtain the optimal target axial power deviation ΔItar value and the initial position of the T-bar group.

[0037] Furthermore, in step 2.3, the simulation calculation module executes the automatic control process of core reactivity and axial power deviation during the load tracking process. The insertion depth of the T-bar group is as shallow as possible, and the core axial power deviation ΔIt can be better controlled within the control dead zone.

[0038] Furthermore, in step 2.3, the simulation calculation module is invoked to perform calculations including the calculation of core reactivity during the load tracking process and the automatic control process of axial power offset.

[0039] Compared with existing technologies, the automatic load tracking simulation method based on Mode-C control and operation mode provided in this application has the following advantages:

[0040] Based on the theoretical simulation requirements of unadjusted boron load tracking under Mode-C control and operation mode, this application proposes automatic simulation strategies and methods, including automatic control of core reactivity and axial power deviation during the load tracking process, automatic search for initial rod positions and target axial power deviations of T-bar groups, automatic optimization using the Keff convergence criterion, and automatic exchange of T-bar group insertion order. These strategies overcome the significant workload inherent in manual simulation of multi-time-step continuous load tracking, significantly improving simulation efficiency while providing automatically optimized key simulation inputs such as initial rod positions and target axial power deviations of T-bar groups. This application significantly improves the efficiency of unadjusted boron load tracking simulation calculations.

[0041] This application enables the automation of theoretical simulation of non-boron load tracking, reducing the workload of manual simulation, improving simulation accuracy and significantly increasing simulation efficiency. Furthermore, it can provide reasonable suggestions for the Keff convergence criterion based on the core state calculation before load tracking, thereby improving simulation efficiency. It can also realize a periodic automatic rod replacement strategy, which allows the burnup shadow caused by long-term insertion of T-bar groups to be released in a timely manner, which is beneficial to the uniformity of core power distribution.

[0042] This application can automatically optimize the initial rod position and target axial power deviation settings, thereby improving the rationality of simulation calculations. Attached Figure Description

[0043] To more clearly illustrate the technical solution of this application, the accompanying drawings used in the technical description will be briefly introduced below.

[0044] Figure 1 is a flowchart of the automatic control strategy for core reactivity and axial power deviation during the load tracking process provided in this application.

[0045] Figure 2 is a flowchart of the automatic search strategy for the initial rod position and target axial power deviation of the T-bar group provided in this application;

[0046] Figure 3 is a control rod arrangement diagram provided in an embodiment of this application;

[0047] Figure 4 is a schematic diagram of the change of the core relative power over simulation time provided in the embodiment of this application;

[0048] Figure 5 is a schematic diagram showing the change of core ΔI with simulation time provided in the embodiment of this application;

[0049] Figure 6 is a schematic diagram of the core boron concentration changing with simulation time according to an embodiment of this application;

[0050] Figure 7 is a schematic diagram showing the change of the position (removal step) of the AO rod group as a function of simulation time according to an embodiment of this application;

[0051] Figure 8 is a schematic diagram showing the change of the position (removal step) of the T-bar group as a function of simulation time in an embodiment of this application. Detailed Implementation

[0052] The following detailed description provides further details on specific implementation methods.

[0053] As shown in Figure 1, this application provides an automatic simulation method for load tracking based on Mode-C control and operation mode, which mainly includes automatic control of core reactivity and axial power deviation during the non-boron load tracking process, and automatic search for the initial position of the T-bar group and the target axial power deviation ΔItar.

[0054] (1) Automatic control of core reactivity and axial power deviation during non-boron load tracking process

[0055] The core task of non-boron load tracking is to simultaneously control the power of the T-bar group and the axial power distribution of the AO-bar group based on a preset load tracking power-time variation curve. This invention achieves load tracking calculation and simulation for a given multi-time step in an automatic manner.

[0056] Automatic control of core reactivity and axial power deviation during the non-boron load tracking process specifically includes:

[0057] Step 1: Read the calculation input data and prepare the data, mainly by initially assigning values ​​to variables based on the input data.

[0058] Input data includes: target axial power deviation, axial power deviation control dead zone and operating band, control rod insertion / removal limits, initial control rod position, Keff convergence criterion, and T-control rod insertion sequence. It should be noted that the Keff convergence criterion is used to indirectly consider the coolant average temperature control dead zone. The T-control rod insertion sequence follows a periodic automatic rod changing strategy (strategy data).

[0059] Step 2: Based on the core power change and corresponding xenon reactivity effect at the current time step, calculate the core Keff at the current control rod group position using existing methods to obtain the degree of deviation from the criticality and the direction of T rod group movement. Further obtain the critical rod position of T rod group through the automatic critical rod position search strategy.

[0060] The current control rod group position is the initial rod position set in the simulation or the control rod position of the previous time step.

[0061] Step 3: Based on the state given in Step 2, calculate the core axial power deviation ΔI and determine whether the set axial power deviation control dead zone requirement is met. This requirement means that the core axial power deviation ΔI is controlled within the control dead zone.

[0062] If satisfied, the simulation will exit the loop (the loop controlled by the critical adjustment of the rod and the core axial power deviation ΔI) and proceed to the next time step or end.

[0063] If the conditions are not met, the automatic core axial deviation control strategy is executed, driving the AO rod group to control the core axial power deviation ΔI within the axial power deviation control dead zone.

[0064] The automatic control strategy for core axial deviation is to automatically exchange the insertion order of T-bar groups.

[0065] The T-bar group periodically switches between two T-bar group loading sequences: T1 to TN and TN to T1; one cycle can be set with an interval of 1000 MWd / tU.

[0066] During the load tracking process, the critical rod position is obtained by searching according to the order of the inserted rods during the automatic control of core reactivity.

[0067] Step 4: Calculate the core Keff at the current control rod group position in Step 3, and determine whether the core Keff satisfies the critical convergence criterion;

[0068] If the critical convergence criterion is met, the loop is exited, and the simulation proceeds to the next time step or terminates.

[0069] If the critical convergence criterion is not met, return to step 2 and perform the bar adjustment critical search again, for example, the T-bar group critical search.

[0070] If an iteration counter is set up and it is indeed impossible to control the dead zone after 5 iterations, then proceed to step 5.

[0071] Step 5: Automatically iterate until the critical convergence criterion is met, and control the core axial power deviation ΔI within the axial power deviation control dead zone;

[0072] If, after several iterations, the core axial power deviation ΔI still cannot be controlled within the axial power deviation control dead zone, determine whether the core axial power deviation ΔI is located in the operating zone. If not, report an error and exit; if so, further determine whether Keff has converged.

[0073] If Keff converges, the loop is exited and the time exceeding the axial power deviation control dead zone is recorded. If Keff does not converge, the process returns to step 2, bar adjustment critical search, and performs one round of steps 2 to 5.

[0074] If it is still not possible to simultaneously satisfy the conditions of control within the operating band and Keff convergence, an error will be reported and the process will exit.

[0075] In this application, the functions of automatic search for the initial position and target axial power deviation of the T-bar group, automatic optimization of the Keff convergence criterion, and automatic exchange of the insertion order of the T-bar group are all to provide input for the automatic control of core reactivity and axial power deviation during the non-boron load tracking process.

[0076] In this application, based on the core reactivity control requirements of the load tracking process, namely the Keff convergence criterion and rod insertion sequence input required for the automatic simulation process without boron adjustment, the following two automatic control sub-functions are provided. The Keff convergence criterion and rod insertion sequence are both inputs for the automatic simulation without boron adjustment, and the suggested values ​​can be obtained automatically, avoiding the tedious manual input.

[0077] ① The Keff convergence criterion is automatically optimized, which is a prerequisite step for steps 1.1 to 1.5, and automatically obtains the suggested value of the Keff convergence criterion.

[0078] When a nuclear power plant is actually operating under load tracking, the average coolant temperature variation range (temperature control dead zone) can be indirectly considered in simulation calculations using the Keff convergence criterion. It should be noted that the closer to the end of the plant's lifespan, the more negative the moderator temperature coefficient (MTC) becomes, and the greater the reactivity represented by the same temperature control dead zone. Therefore, the Keff convergence criterion can be appropriately relaxed towards the end of the plant's lifespan. Theoretical simulations that indirectly consider the temperature control dead zone using the Keff convergence criterion can effectively improve simulation efficiency.

[0079] This invention calculates the corresponding MTC based on the core state before load tracking and provides reasonable suggestions for the Keff convergence criterion for use in the automatic control of core reactivity during the load tracking process.

[0080] ②The insertion order of the T-bar groups is automatically swapped.

[0081] During load tracking, T-bar groups are continuously inserted into the core. If the core is always inserted in the order T1→TN (the order is reversed when removing the core), the insertion frequency of preceding T-bar groups (such as T1) will be much higher than that of other bar groups, inevitably leading to a local burnup shadowing effect. To reduce the impact of the burnup shadowing effect, a periodic automatic bar-changing strategy is designed for the entire life cycle simulation, that is, periodically switching between two T-bar group insertion sequences, T1→TN and TN→T1, at intervals of 1000 MWd / tU. During the automatic core reactivity control during load tracking, the critical bar position is searched based on this insertion sequence. It should be noted that this requires ensuring that the impact of the two T-bar group insertion sequences, T1→TN and TN→T1, on core reactivity is equivalent during the control bar group design.

[0082] (2) Automatic search of the initial rod position and target axial power deviation ΔItar of the T-bar group

[0083] To perform load tracking without boron adjustment, boron adjustment is required before load tracking begins by inserting the T-bar assembly into the reactor core. The initial bar position should be such that the T-bar assembly can be smoothly returned to full power during subsequent load tracking, and the insertion depth should be as shallow as possible to reduce the amount of boron adjustment required before load tracking starts. For example, by generating multiple insertion depth input schemes and performing simulation calculations, the scheme with the shallowest insertion depth can be found among those schemes that can achieve a 96-hour simulation.

[0084] In addition, a target axial power deviation (ΔI) needs to be set during load tracking. tar This effectively drives the AO rod assembly to automatically execute the constant axial power deviation control strategy. Because the core average xenon concentration will be lower when load tracking returns to full power, the T-rod assembly automatically inserts to a deeper depth, causing the core axial power deviation ΔI to become negative. To maintain the core axial power deviation ΔI within the set target axial power deviation ΔI... tar Within the control dead zone, the target axial power deviation ΔI generally needs to be adjusted according to actual requirements. tar Set a more negative value (i.e., more negative in numerical terms, such as -3% or -5%), but at the same time, avoid a target axial power deviation ΔI. tar Excessive negative values ​​can cause the control rod insertion limit (maximum allowable insertion depth of the control group) to be too deep or the fuel consumption shadow to be too large.

[0085] Automatic search of the initial rod position and target axial power deviation ΔItar of the T-bar group includes:

[0086] Based on the ΔItar value (i.e., the target axial power deviation value) and the initial rod position setting range and sampling interval of the T-bar group, multiple schemes are generated (multiple scheme calculations are performed) for parallel calculation. Based on the calculation results, the simulation feasibility, the control of the core axial power deviation ΔI, and the control rod operating range are comprehensively analyzed to obtain the shallowest possible initial rod position of the T-bar group and a reasonable target axial power deviation. Specifically, this includes:

[0087] Step 2.1: Input the ΔItar value and the setting range and sampling interval of the initial rod position of the T rod group;

[0088] Step 2.2: Generate n ΔItar values ​​and m initial bar positions for T bar groups, and combine them to form n×m sets of calculation inputs;

[0089] Step 2.3: Based on the parallel computing strategy, the simulation calculation module is called to perform calculations, namely the calculations of the core reactivity and axial power offset automatic control process during the load tracking process; wherein, the simulation calculation module executes the core reactivity and axial power offset automatic control process during the load tracking process;

[0090] Step 2.4: Analyze the calculation results and provide the optimal ΔItar value and the initial rod position of the T-bar group. Among the various schemes under the simulated feasible conditions, the initial rod position of the T-bar group is the shallowest, and the core axial power deviation ΔI can be controlled better; and it serves as the optimal input for the simulation calculation.

[0091] To further understand the present invention, the following detailed description of the automatic load tracking simulation method based on Mode-C control and operation mode provided by the present invention is provided in conjunction with embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0092] Example

[0093] The simulation was conducted based on the core and control rod arrangement shown in Figure 3. In the figure, T1, T2, T3, T4, T5, and T6 are T-bar groups, T1, T2, T3, and T4 are gray bars, and the remaining T5 and T6 are black bars. There are a total of 28 bundles in the T-bar groups and 9 bundles in the AO bar groups. The overlap steps of the T-bar groups are 88, 88, 88, 16, and 16. An automatic simulation of non-boron load tracking was performed for 90% of the first cycle length, with a "14-2-6-2" configuration. "14-2-6-2" refers to running at full power for 12 hours, reducing to 50% power for 2 hours, running at 50% power for 6 hours, and returning to full power for 2 hours.

[0094] The automatic simulation method for non-boron load tracking in this embodiment mainly includes:

[0095] S1: Input data preparation;

[0096] S2: Based on the core power change and corresponding xenon reactivity effect at the current time step, calculate the core Keff at the current control rod group position, obtain the degree of deviation from the criticality and the direction of action of the T rod group, and further obtain the critical rod position of the T rod group through the automatic search strategy for critical rod position.

[0097] S3: Calculate the core axial power deviation ΔI given in S2, and determine whether the set core axial power deviation control dead zone is met.

[0098] If the condition is met, the loop will exit and the simulation will proceed to the next time step or the process will end.

[0099] If the conditions are not met, the automatic core axial deviation control strategy is executed, driving the AO rod group to control the core axial power deviation ΔI within the axial power deviation control dead zone.

[0100] Based on the core axial power deviation ΔI, and using the set core axial power deviation control dead zone and operating zone, the core axial deviation is effectively controlled within the preset control range through the core axial deviation automatic control strategy.

[0101] S4: Calculate the core Keff at the current control rod group position in S2 and S3;

[0102] If the critical convergence criterion is met, the loop is exited, and the simulation proceeds to the next time step or terminates.

[0103] If the critical convergence criterion is not met, return to S2 and execute the bar adjustment critical search again;

[0104] S5: Automatically iterate until the critical convergence criterion is met, and control the core axial power deviation ΔI within the axial power deviation control dead zone;

[0105] If, after several iterations, it is still impossible to control the core axial power deviation ΔI within the axial power deviation control dead zone, determine whether the core axial power deviation ΔI is located in the operating zone.

[0106] If not, an error message will be displayed and the program will exit; if yes, further checks will be performed to determine whether Keff has converged.

[0107] If Keff converges, the loop is exited and the time exceeding the axial power deviation control dead zone is recorded. If Keff does not converge, the process returns to the S2 bar adjustment critical search and performs one round of S2 to S5 operations.

[0108] If it is still not possible to simultaneously satisfy the conditions of control within the operating band and Keff convergence, an error will be reported and the process will exit.

[0109] Based on the automatic search strategy for the initial bar position and target axial power deviation ΔItar of the T-bar group shown in Figure 2, the range of the initial bar position of the T-bar group is set to 100 to 400 (total number of steps in the T-bar group, insertion steps), with a point selection interval of 20 steps; the range of ΔItar is -6.20% to -10.20%, with a point selection interval of 1.00%; a total of 5×16=80 sets of calculation inputs are generated. The simulation calculation module is called through a parallel computing strategy to carry out comprehensive evaluation calculations, thereby obtaining the optimal initial bar position and ΔItar of the T-bar group.

[0110] Regarding the automatic optimization of the Keff convergence criterion, the MTC value is automatically calculated to be approximately 50 pcm / ℃ based on the state before load tracking. Assuming a temperature control dead zone of 0.83℃ to 1.66℃, the Keff convergence criterion can be relaxed to 0.0004 to 0.0008.

[0111] Regarding the automatic exchange of T-bar group insertion order, the T-bar group insertion order is set to be automatically exchanged every 1000MWd / tU. Based on the simulation of the previous burnup step, the T-bar group insertion order is automatically set to T1→T6 at the 90% EOL burnup time.

[0112] The effects produced by the application of this embodiment are shown in Figures 4 to 8. Based on the above-mentioned automatic simulation method, the simulation calculation results of this embodiment can efficiently realize the simulation of "14-2-6-2" daily load tracking without boron adjustment for 96 hours, while accurately controlling the core ΔI within the control dead zone of ±1% above and below the ΔItar value.

[0113] The above description is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application.

Claims

1. A method for automatic load tracking simulation based on Mode-C control and operation mode, characterized in that, Automatic control of core reactivity and axial power deviation during boron load tracking process includes: Step 1: Read the input data and prepare the data; Step 2: Based on the core power change and corresponding xenon reactivity effect at the current time step, perform automatic search for the bar adjustment criticality; Step 3: Calculate the core axial power deviation ΔI and determine whether it is within the operating dead zone of the core axial power deviation ΔI. If so, exit the loop and proceed to the next time step simulation or terminate the process; otherwise, execute the automatic control of the operation belt and perform the core axial power deviation ΔI search calculation. Step 4: Calculate the core Keff at the current control rod group position, and determine whether the core Keff has converged. If yes, exit the loop and proceed to the next time step simulation or end the simulation; otherwise, return to step 2. Step 5: Automatically iterate until the critical convergence criterion is met, and control the core axial power deviation ΔI within the axial power deviation control dead zone; If, after several iterations, the core axial power deviation ΔI still cannot be controlled within the axial power deviation control dead zone, determine whether the core axial power deviation ΔI is located in the operating zone. If not, report an error and exit; if so, further determine whether Keff has converged. If Keff converges, the loop is exited and the time exceeding the axial power deviation control dead zone is recorded. If Keff does not converge, step 2 is returned and one round of steps 2 to 5 is executed. If it is still not possible to simultaneously satisfy the conditions of control within the operating band and Keff convergence, an error will be reported and the process will exit.

2. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 1, characterized in that, In step 1, the input data includes: target axial power deviation, axial power deviation control dead zone and operating band, control rod group insertion and extraction limits, initial control rod position, Keff convergence criterion, and T control rod group insertion sequence.

3. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 1, characterized in that, In step 2, the core Keff at the current control rod group position is calculated to obtain the degree of deviation from the criticality and the direction of action of the T rod group. The critical rod position of the T rod group is obtained through the automatic search strategy for critical rod position.

4. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 3, characterized in that, The current control rod group position is the initial rod position set in the simulation or the control rod position of the previous time step.

5. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 1, characterized in that, In step 3, when performing automatic control of core axial deviation, the core axial power deviation ΔI is controlled within the axial power deviation control dead zone by driving the AO rod group.

6. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 1, characterized in that, Automatic search for the initial rod position and target axial power deviation of the T-bar group, automatic optimization of the Keff convergence criterion, and automatic exchange of the T-bar group insertion order provide input for the core reactivity and axial power deviation in the automatic control of the boron-free load tracking process.

7. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, The T-bar group is periodically switched between two T-bar group loading sequences: T1 to TN and TN to T1.

8. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, The cycle is set to 1000MWd / tU as the interval.

9. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, During the load tracking process, the critical rod position is obtained by searching according to the order of the inserted rods during the automatic control of core reactivity.

10. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, Before load tracking, boron adjustment is performed, and the T-bar group is inserted into the reactor core. Its initial bar position is inserted into the reactor core on the premise that the T-bar group can be smoothly returned to full power during the subsequent load tracking process.

11. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 10, characterized in that, By generating multiple insertion depth input schemes for simulation calculation, the scheme with the shallowest insertion depth is obtained among the schemes that achieve a 96-hour simulation.

12. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, During load tracking, set the target axial power deviation ΔI. tar This drives the AO rod assembly to automatically perform constant axial deviation control.

13. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, The target axial power deviation ΔI is determined according to actual needs. tar The setting is relatively negative.

14. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 13, characterized in that, A more negative value would be -3% or -5%.

15. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6, characterized in that, Based on the target axial power deviation ΔItar value and the setting range and sampling interval of the initial rod position of the T-rod group, multiple schemes are formed for parallel calculation. Based on the calculation results, the simulation feasibility, the control of the core axial power deviation ΔI, and the operating range of the control rods are analyzed to obtain the initial rod position of the T-rod group and the target axial power deviation.

16. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 6 or 15, characterized in that, The automatic search for the initial rod position and target axial power deviation of the T-bar group includes the following steps: Step 2.1: Input the target axial power deviation ΔItar value and the setting range and sampling interval of the initial rod position of the T-bar group; Step 2.2: Generate n target axial power deviation ΔItar values ​​and m initial rod positions for T-bar groups, and combine them to form n×m sets of calculation inputs; Step 2.3: Invoke the simulation computing module to perform calculations based on the parallel computing strategy; Step 2.4: Analyze the calculation results to obtain the target axial power deviation ΔItar value and the initial position of the T-bar group.

17. The automatic load tracking simulation method based on Mode-C control and operation mode according to claim 16, characterized in that, In step 2.3, the simulation calculation module executes the automatic control process for core reactivity and axial power offset during the load tracking process.

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