Load tracking automatic simulation method based on Mode-C control and operation mode

Abstract

The invention belongs to the technical field of load tracking simulation, and aims to solve the problem of huge workload faced by manual simulation of multi-time-step continuous load tracking. The invention discloses a load tracking automatic simulation method based on a Mode-C control and operation mode. The reactivity and axial power deviation of a reactor core in the boron-free load tracking process are automatically controlled. According to the method, the automation of theoretical simulation of boron-free load tracking can be realized, the workload of manual simulation is reduced, the simulation accuracy is improved, the simulation efficiency is remarkably improved, automatic optimization of initial rod position and target axial power deviation setting can be realized, and the reasonability of simulation calculation is improved.

Description

Technical Field

[0001] The present application belongs to the technical field of load tracking simulation, and in particular, to a method for automatic simulation of load tracking based on Mode-C control and operation mode. Background Art

[0002] Operation and control mode refers to the regulation and control method of the range of change of parameters such as power level, axial deviation, average core coolant temperature, etc. when the reactor is operating under various allowable operating conditions through the use of control rods, soluble boron, etc. Operation and control mode design technology is a mature design technology abroad, such as the widely used Mode-A, Mode-G and MSHIM modes.

[0003] Mode-A and Mode-G have good base load operation capabilities, and only a small number of control rods (D / R) need to be inserted into the core to meet normal operation requirements. Compared with Mode-A, Mode-G has a relatively enhanced load tracking operation capability, but both modes require frequent boron adjustment operations during load tracking, which brings the following shortcomings: a large amount of radioactive waste liquid is generated, and the use of boron adjustment operations at the end of the life cycle will produce multiple times of waste liquid at the beginning of the life cycle; the boron adjustment operation is relatively frequent and is implemented manually, which increases the burden on the operator. The MSHIM mode realizes load tracking operation without boron adjustment and has good load tracking operation capabilities, but during base load operation, a large number of control rods (array control rods and AO rod groups in MA, MB, MC, and MD) are still inserted into the core, reducing some safety margins and bringing certain hidden economic losses, such as control rod burnup loss and difficulty in rod extraction at the end of the life cycle. Among them, the M rod group is a named rod group unique to the MSHIM mode and is not used in other modes; the AO rod group description is used first in the MSHIM mode, and the Mode-C mode is also used for reference.

[0004] In recent years, in view of the operating characteristics of domestic PWR nuclear power plants, which are mainly based on base load operation and have less demand for load tracking operation, the Mode-C operation and control mode design has been carried out for the first time. This mode takes the best of many: for the main operation mode (base load) during the life cycle, the most widely used control strategy is maintained unchanged, and there is mature operation and practical experience for reference, which is conducive to the safe and economical operation of nuclear power plants. For operation modes with less demand during the life cycle (such as load tracking and xenon oscillation), the MSHIM mode is referred to, and control rods are used instead of adjusting soluble boron for core reactivity control. Reactivity and power distribution control are automatically completed through the rod control system, which improves economy and greatly reduces the burden on operators.

[0005] The Mode-C operation and control mode sets two sets of independently controlled regulating rod groups according to their functions: the T rod group and the AO rod group. The T rod group moves in accordance with the prescribed overlapping steps and sequence; when performing load tracking, the depth of the T rod group inserted into the core is determined by the total amount of various reactivity in the core, and is used to maintain the core reactivity balance or maintain the relationship between the average temperature and power of the reactor according to a certain rule. The AO rod group is generally inserted less into the core and only operates in an operating band at the top of the core; it is mainly used for axial power distribution control to control the axial deviation of the core within the target value range.

[0006] In the Mode-C operation and control mode, non-boron operation can be achieved during the typical daily load tracking process within at least 90% of the cycle length. In order to minimize the human intervention during the non-boron load tracking operation, it is necessary to conduct a theoretical simulation of non-boron load tracking in advance, that is, how to reasonably use the core reactivity control means, such as control rod groups, core feedback characteristics, etc., without adjusting the core boron concentration during the load tracking process, so that the load tracking process is carried out according to the preset power-time variation curve, and the key core parameters such as the core axial deviation are effectively controlled. In the existing technology, only manual simulation can be performed. If manual simulation is used, it will face a huge workload and the simulation efficiency is very low. Summary of the invention

[0007] The purpose of this application is to provide an automatic simulation method for load tracking based on Mode-C control and operation mode to solve the huge workload problem faced by manual simulation of multi-time step continuous load tracking.

[0008] In order to achieve the above objectives, this application provides the following technical solutions:

[0009] An automatic simulation method for load tracking based on Mode-C control and operation mode, which automatically controls the core reactivity and axial power deviation during the load tracking process without boron adjustment, includes:

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

[0011] Step 2: According to the core power change and the corresponding xenon reactivity effect at the current time step, perform the rod adjustment criticality automatic search;

[0012] Step 3: Calculate the core axial power deviation ΔI, and determine whether it is in the operation dead zone of the core axial power deviation ΔI. If so, jump out of the loop and simulate the next time step or end; if not, execute the operation with automatic control and perform the search calculation of the core axial power deviation ΔI;

[0013] Step 4: Calculate the core Keff under the current control rod group position and determine whether the core Keff meets the critical convergence criterion. If so, exit the loop and simulate the next time step or end; if not, return to step 2;

[0014] Step 5: Automatically iterate until the critical convergence criterion is met and the core axial power deviation ΔI is controlled 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 in the operating zone, if not, report an error and exit; if so, further determine whether Keff converges;

[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, the loop returns to step 2 and executes one round of steps 2 to 5.

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

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

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

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

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

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

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

[0024] Furthermore, the period is set at an interval of 1000MWd / tU.

[0025] Furthermore, during the automatic control of core reactivity during the load following process, the critical rod position is searched according to the rod insertion sequence.

[0026] Furthermore, before load following, boron adjustment is performed and the T-rod group is inserted into the core. The initial rod position is inserted into the core on the premise that the requirement of smoothly returning to full power by lifting the T-rod group in the subsequent load following process is met.

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

[0028] Furthermore, during load tracking, the target axial power deviation ΔI is set tar To drive the AO rod group to automatically perform core axial power deviation ΔI control.

[0029] Furthermore, according to actual needs, the target axial power deviation ΔI tar Set more negative.

[0030] Further, more negative is -3% or -5%.

[0031] Furthermore, according to the target axial power deviation ΔItar value and the setting range and point interval of the initial rod position of the T-rod group, multiple schemes are formed for parallel calculation. According to the calculation results, the simulation feasibility, the control status of the core axial power deviation ΔI and the control rod operation range 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 of the T rod group and the target axial power deviation includes the following steps:

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

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

[0035] Step 2.3: Call the simulation calculation module to perform calculation 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 rod position of the T rod group.

[0037] Furthermore, in step 2.3, the simulation calculation module executes the automatic control process of the core reactivity and axial power deviation during the load tracking process, the insertion depth of the T-rod 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 called to perform calculations including calculations of the core reactivity during the load tracking process and the axial power offset automatic control process.

[0039] Compared with the prior art, the load following automatic simulation method based on Mode-C control and operation mode provided in this application has the following beneficial effects:

[0040] According to the theoretical simulation requirements of load tracking without boron adjustment under Mode-C control and operation mode, this application proposes automatic simulation strategies and methods such as automatic control of core reactivity and axial power deviation during load tracking, automatic search of initial rod position of T rod group and target axial power deviation, automatic optimization of Keff convergence criterion and automatic exchange of T rod group insertion order, which overcomes the defect of huge workload faced by manual simulation of multi-time step continuous load tracking, and can provide key simulation inputs such as automatically optimized initial rod position of T rod group and target axial power deviation while significantly improving simulation efficiency. This application significantly improves the efficiency of simulation calculation of load tracking without boron adjustment.

[0041] The present application can realize the automation of theoretical simulation of load tracking without adjusting boron, reduce the workload of manual simulation, improve simulation accuracy and significantly improve simulation efficiency; further, reasonable suggestions for Keff convergence criterion can be given according to the core state calculation before load tracking to improve simulation efficiency; and a periodic automatic rod replacement strategy can be realized, so that the fuel consumption shadow caused by the long-term insertion of the T-rod group can be released in time, which is beneficial to the uniformity of core power distribution.

[0042] This application can realize automatic optimization of the initial rod position and the target axial power deviation setting, and improve the rationality of the simulation calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for the technical description.

[0044] Figure 1 A flow chart of the automatic control strategy for core reactivity and axial power deviation during the load following process provided in this application;

[0045] Figure 2 A flow chart of the automatic search strategy for the initial rod position and target axial power deviation of the T rod group provided in this application;

[0046] Figure 3 A control rod arrangement diagram provided for an embodiment of the present application;

[0047] Figure 4 A schematic diagram of the change of the core relative power with the simulation time provided in the embodiment of the present application;

[0048] Figure 5A schematic diagram of the change of core ΔI with simulation time provided in an embodiment of the present application;

[0049] Figure 6 A schematic diagram of the variation of the boron concentration in the core with the simulation time provided in the embodiment of the present application;

[0050] Figure 7 A schematic diagram of the change of the position (step) of the AO rod group with the simulation time provided in the embodiment of the present application;

[0051] Figure 8 A schematic diagram of the change of the T-bar group position (proposed step) with simulation time provided in an embodiment of the present application. DETAILED DESCRIPTION

[0052] The following is further explained in detail through specific implementation methods.

[0053] like Figure 1 As shown, the present 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 load tracking without boron adjustment, and automatic search for the initial rod position of the T-rod group and the target axial power deviation ΔItar.

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

[0055] The core task of load tracking without adjusting boron is to track the power-time variation curve according to the preset load, and realize the control of power by the T rod group and the control of axial power distribution by the AO rod group at the same time. The present invention realizes the load tracking calculation simulation of given multiple time steps in an automatic way.

[0056] The 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 to perform initial variable assignment based on the input data.

[0058] The input data include: target axial power deviation, axial power deviation control dead zone and operation band, control rod group insertion / extraction limit, control rod initial rod position, Keff convergence criterion, T control rod group insertion sequence, etc. It should be noted that the Keff convergence criterion is used to indirectly consider the coolant average temperature control dead zone. The T rod group insertion sequence executes the periodic automatic rod replacement strategy (strategy data).

[0059] Step 2: According to the core power change in the current time step and the corresponding xenon reactivity effect, the core Keff at the current control rod group position is calculated by the existing method to obtain the degree of deviation from criticality and the direction of movement of the T rod group, and further obtain the critical rod position of the T rod group through the critical rod position automatic search strategy.

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

[0061] Step 3: According to the state given in step 2, the core axial power deviation ΔI is calculated to determine whether the set axial power deviation control dead zone requirement is met, which means that the core axial power deviation ΔI is controlled within the control dead zone;

[0062] If satisfied, the loop (the loop of rod adjustment criticality and core axial power deviation ΔI control) is jumped out, and the simulation of the next time step is carried out or ended;

[0063] If not, the core axial deviation automatic control strategy is executed to drive 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-rod groups.

[0065] The T-rod group is periodically switched between the two T-rod group stacking sequences of T1 to TN and TN to T1; one cycle can be set as an interval of 1000MWd / tU.

[0066] During the load following process, the critical rod position is searched according to the rod insertion sequence during automatic control of the 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 meets 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 ends;

[0069] If the critical convergence criterion is not met, return to step 2 and perform the critical search of the adjustment rod, such as the critical search of the adjustment T rod group.

[0070] An iteration counter is provided. If the dead zone control cannot be achieved according to the relevant settings (such as after 5 iterations), the process goes to step 5.

[0071] Step 5: Automatically iterate until the critical convergence criterion is met and the core axial power deviation ΔI is controlled 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 in the operating zone, if not, report an error and exit; if so, further determine whether Keff converges;

[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 loop returns to step 2 for the critical search of the rod adjustment and performs one round of operations from step 2 to step 5.

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

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

[0076] In the present application, according to the core reactivity control requirements of the load tracking process, that is, 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 recommended values ​​can be automatically obtained to avoid tedious manual input.

[0077] ① Automatic optimization of the Keff convergence criterion, which is a preceding step of steps 1.1 to 1.5, and automatically obtains the recommended value of the Keff convergence criterion.

[0078] When a nuclear power plant actually performs load following operation, the average coolant temperature varies in a range (temperature control dead zone). The impact of this temperature variation range can be indirectly considered through the Keff convergence criterion in the simulation calculation. It should be pointed out that the closer to the end of life, the more negative the moderator temperature coefficient (MTC), the greater the reactivity represented by the same temperature control dead zone, and the Keff convergence criterion can be appropriately relaxed at the end of life. The theoretical simulation method of indirectly considering the temperature control dead zone through the Keff convergence criterion can effectively improve the simulation efficiency.

[0079] The present invention calculates the corresponding MTC according to the core state before load following, and gives reasonable suggestions of Keff convergence criterion for automatic control of core reactivity during load following process.

[0080] ②The insertion order of the T-bar group is automatically changed.

[0081] During load tracking, T rod groups are inserted into the core all the time. If they are inserted into the core in the order of T1→TN (the order is reversed when the core is withdrawn), the frequency of insertion of T1 and other preceding rod groups into the core is much higher than that of other rod groups, which is bound to lead to local burnup shadow effect. In order to reduce the impact of burnup shadow effect, a periodic automatic rod replacement strategy is designed for full life simulation, that is, periodically (such as 1000MWd / tU as an interval) switching between the two T rod group insertion orders of T1→TN and TN→T1. During the load tracking process, the critical rod position is searched according to the rod insertion order when the core reactivity is automatically controlled. It should be noted that this requires that when designing the control rod group, the effects of the two T rod group insertion orders of T1→TN and TN→T1 on the core reactivity are equivalent.

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

[0083] In order to perform load following operation without boron adjustment, boron adjustment is required to insert the T rod group into the reactor core before load following. The initial rod position should be as shallow as possible under the premise that the full power can be smoothly returned by lifting the T rod group in the subsequent load following process, so as to reduce the amount of boron adjustment before the start of load following. For example, by generating multiple insertion depth input schemes for simulation calculation, find the scheme with the shallowest insertion depth among the schemes that can achieve 96 hours of simulation.

[0084] In addition, a target axial power deviation (ΔI tar ) to effectively drive the AO rod group to automatically execute the constant axial deviation control strategy. Since the average xenon concentration in the core will be lower when the load tracking returns to full power, the T rod group will automatically be inserted to a deeper level, making the core axial power deviation ΔI negative. In order to maintain the core axial power deviation ΔI within the set target axial power deviation ΔI tar In the control dead zone, the target axial power deviation ΔI is generally required to be adjusted according to actual needs. tar The setting is more negative (i.e. more negative in value, such as -3% or -5%), but at the same time, the target axial power deviation ΔI must be avoided tar Too negative will result in a deeper control rod insertion limit (maximum allowable insertion depth of the control group) or a larger fuel consumption shadow.

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

[0086] According to the ΔItar value (i.e., the target axial power deviation value) and the setting range and point interval of the initial rod position of the T rod group, multiple schemes are formed (multi-scheme calculation is generated) for parallel calculation. According to the calculation results, the simulation feasibility, the control of the core axial power deviation ΔI and the control rod operation range are comprehensively analyzed to obtain the shallowest possible initial rod position of the T rod group and a reasonable target axial power deviation. Specifically, it includes:

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

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

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

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

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

[0092] Example

[0093] based on Figure 3 The arrangement of the core and control rods is simulated. In the figure, T1, T2, T3, T4, T5, and T6 are T rod groups, T1, T2, T3, and T4 are gray rods, and the remaining T5 and T6 are black rods; there are 28 bundles in the T rod group, and 9 bundles in the AO rod group; the overlapping steps of the T rod group are 88, 88, 88, 16, and 16. For the first cycle 90% cycle length, the "14-2-6-2" non-boron load tracking automatic simulation is carried out, where "14-2-6-2" means full power operation for 12 hours, 2 hours down to 50% power, 50% power operation for 6 hours, and 2 hours back to full power operation.

[0094] The automatic simulation method for load tracking without adjusting boron in this embodiment mainly includes:

[0095] S1: Input data preparation;

[0096] S2: According to the core power change in the current time step and the corresponding xenon reactivity effect, the core Keff under the current control rod group position is calculated to obtain the degree of deviation from criticality and the direction of the T rod group movement, and further obtain the critical rod position of the T rod group through the critical rod position automatic search strategy;

[0097] S3: Calculate the core axial power deviation ΔI of the state given in S2, and determine whether it satisfies the set core axial power deviation control dead zone;

[0098] If satisfied, the loop is exited and the simulation is performed at the next time step or ends;

[0099] If it is not satisfied, the core axial deviation automatic control strategy is executed to drive the AO rod group to control the core axial power deviation ΔI within the axial power deviation control dead zone;

[0100] According to the core axial power deviation ΔI, based on the set core axial power deviation control dead zone and operation 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 under the current control rod group position in S2 and S3;

[0102] If the critical convergence criteria are met, the loop is exited and the simulation is performed at the next time step or ends;

[0103] If the critical convergence criterion is not met, return to S2 and perform the critical search for adjusting the rod;

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

[0105] If the core axial power deviation ΔI still cannot be controlled within the axial power deviation control dead zone after several iterations, it is determined whether the core axial power deviation ΔI is within the operating zone;

[0106] If not, report an error and exit; if so, further determine whether Keff converges;

[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 loop returns to S2 to perform critical search of the rod adjustment and executes one round of operations from S2 to S5.

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

[0109] according to Figure 2 The automatic search strategy for the initial rod position of the T-rod group and the target axial power deviation ΔItar is shown. The initial rod position range of the T-rod group is set to 100-400 (total number of steps of the T-rod group, insertion step), and the point interval is 20 steps; the ΔItar range is -6.20% to -10.20%, and the point interval is 1.00%; a total of 5×16=80 groups of calculation inputs are generated, and the simulation calculation module is called through the parallel calculation strategy to carry out comprehensive evaluation calculations, so as to obtain the optimal initial rod position and ΔItar of the T-rod group.

[0110] In terms of automatic optimization of the Keff convergence criterion, the MTC value is automatically calculated based on the state before load tracking, which is approximately 50pcm / ℃. 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 the T-rod group insertion order, the T-rod group insertion order is set to be automatically exchanged every 1000MWd / tU. According to the simulation of the previous burnup step, the T-rod group insertion order is automatically set to T1→T6 at 90% EOL burnup.

[0112] Through the application of this embodiment, the effects produced are as follows: Figures 4 to 8 As shown, based on the above automatic simulation method, the simulation calculation results of this embodiment can efficiently realize a 96-hour "14-2-6-2" daily load tracking simulation without boron adjustment, while accurately controlling the core ΔI within a control dead zone of ±1% above and below the ΔItar value.

[0113] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed in the present application should be covered within the protection scope of the present application.

Claims

1. A method for automatic simulation of load following based on Mode-C control and operation mode, characterized in that: Automatically control the core reactivity and axial power deviation during the non-boron load tracking process, including: Step 1: Read input data and prepare data; Step 2: According to the core power change and the corresponding xenon reactivity effect in the current time step, the rod adjustment criticality automatic search is performed; Step 3: Calculate the core axial power deviation ΔI, and determine whether it is in the operation dead zone of the core axial power deviation ΔI. If so, jump out of the loop and simulate the next time step or end; if not, execute the operation with automatic control and perform the search calculation of the core axial power deviation ΔI; Step 4: Calculate the core Keff under the current control rod group position and determine whether the core Keff converges. If so, exit the loop and simulate the next time step or end; if not, return to step 2; Step 5: Automatically iterate until the critical convergence criterion is met and the core axial power deviation ΔI is controlled 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 in the operating zone, if not, report an error and exit; if so, further determine whether Keff converges; 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 loop returns to step 2 and executes one round of steps 2 to 5. If it is still not possible to simultaneously satisfy the control within the operating band and Keff convergence, an error will be reported and the program will exit.

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

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

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

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

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

7. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 6 is characterized in that: The T-bar groups are periodically switched between the two T-bar group stacking sequences of T1 to TN and TN to T1.

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

9. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 6 is characterized in that: During the load following process, the critical rod position is searched according to the rod insertion sequence during automatic control of the core reactivity.

10. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 6, characterized in that: Boron adjustment is performed before load tracking, and the T-rod group is inserted into the core. Its initial rod position is inserted into the core on the premise that the requirement of smoothly returning to full power by lifting the T-rod group in the subsequent load tracking process is met.

11. The method for automatic simulation of load following 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 for realizing 96 hours of simulation.

12. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 6, characterized in that: During load following, set the target axial power deviation ΔI tar To drive the AO rod group to automatically perform constant axial deviation control.

13. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 6, characterized in that: According to actual needs, the target axial power deviation ΔI tar Set more negative.

14. The method for automatic simulation of load following based on Mode-C control and operation mode according to claim 13, characterized in that: More negative is -3% or -5%.

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

16. The method for automatic simulation of load following 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 rod group includes the following steps: Step 2.1: Input the target axial power deviation ΔItar value and the setting range and point interval of the initial rod position of the T rod group; Step 2.2: Generate n target axial power deviation ΔItar values ​​and m initial rod positions of T rod groups, and combine them to form n×m sets of calculation inputs; Step 2.3: Call the simulation calculation module to perform calculation 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 rod position of the T rod group.

17. The method for automatic simulation of load following 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 of core reactivity and axial power deviation during the load tracking process.

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