A nuclear reactor LPD online protection method and system

Abstract

The present invention relates to the field of nuclear safety technology, and more specifically, to a method and system for online protection of nuclear reactors using LPD. The method and system provided by the present invention mainly include utilizing a core measurement system detector to provide a measured current, combining the current core measured operating state parameters to achieve rapid calculation of protection parameters, introducing real-time measured core operating state parameters as input items for rapid calculation of protection parameters, and calculating intermediate parameters based on the current core state. The above method solves the hysteresis problem of the intermediate coefficient used in the calculation of protection parameters in existing online protection technologies, significantly reduces the uncertainty of online protection parameter calculations, and improves the accuracy of protection parameter calculations. By leveraging online protection technology, it has a significant effect on improving the reactor operating range, further exploring the operational flexibility and economy of nuclear power plant units.

Description

Technical Field

[0001] The present invention relates to the field of nuclear safety technology, and in particular to a nuclear reactor LPD online protection method and system. Background Art

[0002] To prevent fuel assembly meltdown during operation, pressurized water reactors (PWRs) require the fuel cladding temperature to remain below a certain limit. This limits the core linear power density (LPD) during reactor operation, requiring the maximum LPD value for the entire reactor to remain below a certain limit. In existing PWRs, these core protection parameters (LPD) are primarily limited by operating diagrams, overtemperature ΔT, and overpower ΔT protection, thereby protecting the core during operation. These core protection parameters are implemented by setting operating diagrams, overtemperature ΔT, and overpower ΔT channels. These channels restrict the reactor's operating range and flexibility, impacting its economic efficiency.

[0003] Online protection technology for pressurized water reactors (PWRs) utilizes a core measurement system within the reactor to obtain real-time neutron flux data. This core measurement system enables online calculation of full-stack protection parameters, ultimately enabling online reactor protection. However, existing online protection technologies suffer from significant uncertainty due to the significant lag in the intermediate coefficients used in the protection parameter calculations. This significant system uncertainty compresses the operating range expanded by the online protection system, resulting in limited improvements in the reactor's operating range. Summary of the Invention

[0004] The purpose of the present invention is to provide a nuclear reactor LPD online protection method and system to solve the above problems in the prior art.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a nuclear reactor LPD online protection method, comprising:

[0007] Triggering a three-dimensional simulation calculation of the core periodically to simulate the core behavior under a number of preset operating conditions and obtain the first intermediate coefficients under the preset operating conditions;

[0008] Acquiring a currently measured core state parameter, and calculating a second intermediate coefficient based on the currently measured core state parameter by combining the currently measured core state parameter with the first intermediate coefficient;

[0009] Acquire the measured current data of the core neutron flux, calculate the protection parameter LPD by using the measured current data of the core neutron flux and the second intermediate coefficient, and obtain the protection parameter LPD;

[0010] A limit value of the protection parameter LPD is set, a current reactor operation safety margin is determined by the protection parameter LPD and the limit value, and the value of the safety margin is output.

[0011] Preferably, the operating conditions include setting core power, average moderator temperature, primary circuit pressure, control rod position or critical boron concentration.

[0012] Preferably, obtaining the first intermediate coefficient under a plurality of preset operating conditions includes:

[0013] Establish a three-dimensional geometric model of the core and the material distribution, solve the neutron diffusion equation to simulate the behavior of neutrons in the core, and obtain the spatial and energy distribution of neutrons;

[0014] determining a first intermediate coefficient based on the spatial and energy distribution of the neutrons;

[0015] Preferably, obtaining the second intermediate coefficient based on the currently measured core state parameter includes:

[0016] Establishing a mapping relationship between the first intermediate coefficient and the preset operating condition;

[0017] Determining a second intermediate coefficient in the mapping relationship according to the current measured core state parameter;

[0018] Preferably, the calculation of the protection parameter LPD using the measured core neutron flux current data and the second intermediate coefficient includes:

[0019] S=K2*I*P

[0020] Where S is the protection parameter LPD, I is the measured current data of the core neutron flux, K2 is the second intermediate coefficient, and P is the core relative power.

[0021] In a second aspect, the present invention provides a nuclear reactor LPD online protection system, comprising:

[0022] The coefficient determination module is configured to periodically trigger a three-dimensional simulation calculation of the core, simulate the core behavior under a number of preset operating conditions, and obtain a first intermediate coefficient under the plurality of preset operating conditions; obtain currently measured core state parameters, and calculate a second intermediate coefficient based on the currently measured core state parameters by combining the measured core state parameters with the first intermediate coefficient;

[0023] a protection parameter module configured to obtain measured core neutron flux current data, calculate a protection parameter LPD using the measured core neutron flux current data and a second intermediate coefficient to obtain the protection parameter LPD, set a limit value for the protection parameter LPD, determine a current reactor operation safety margin using the protection parameter LPD and the limit value, and output the value of the safety margin;

[0024] The main control device is connected to the coefficient determination module and the protection parameter module, and is used to execute the above-mentioned nuclear reactor LPD online protection method.

[0025] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0026] The method and system provided by the present invention mainly include using the core measurement system detector to provide the measured current, and combining it with the current core measured operating state parameters to realize the rapid calculation of protection parameters, wherein the reactor core operating state parameters include but are not limited to power level, average moderator temperature, primary circuit pressure, control rod position, critical boron concentration and other data. Based on the above core operation measured data, the protection parameters are quickly calculated, and the real-time measured core operating state parameters are introduced as input items for the rapid calculation of protection parameters to calculate the intermediate parameters based on the current core state. The above method solves the hysteresis problem of the intermediate coefficient used in the calculation of protection parameters in the existing online protection technology, significantly reduces the uncertainty of online protection parameter calculation, improves the accuracy of protection parameter calculation, and has a significant effect on improving the reactor operating range by leveraging online protection technology, further exploring the operational flexibility and economy of nuclear power plant units. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 It is a schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0030] The terms "first," "second," and so on, in the specification and claims of this application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. The naming or numbering of steps in this application does not necessarily imply that the steps in the method flow must be executed in the chronological or logical order indicated by the naming or numbering. Named or numbered process steps may be executed in a different order based on the desired technical objectives, as long as the same or similar technical effects are achieved.

[0031] Independently described modules or submodules may or may not be physically separate; they may be implemented in software or hardware. Some modules or submodules may be implemented in software, with the processor invoking the software to implement the functionality of these modules or submodules, while other modules or submodules may be implemented in hardware, such as hardware circuits. Furthermore, some or all of the modules may be selected based on actual needs to achieve the objectives of the present application.

[0032] Please refer to Figure 1 The present invention provides a nuclear reactor LPD online protection method, comprising:

[0033] S101: triggering a three-dimensional simulation calculation of the core periodically to simulate the core behavior under a number of preset operating conditions and obtain a first intermediate coefficient under the plurality of preset operating conditions;

[0034] Upgrade the reactor core state parameter measurement system to safety level, and implement core online protection based on the safety-level measured core state parameters;

[0035] Among them, for the typical operating conditions at the typical burnup time of the reactor operation, the first intermediate coefficients under multiple sets of preset operating conditions are calculated. The first intermediate coefficients are manually triggered and calculated according to the period and transmitted to the protection parameter computer. During the transmission process, manual verification is performed to confirm that the data transmission is normal to ensure the integrity and accuracy of the data.

[0036] For the typical operating conditions at typical burnup times of the reactor, the core operation under multiple sets of preset operating conditions (including multiple sets of core power, average moderator temperature, primary circuit pressure, control rod position, critical boron concentration, etc.) is simulated, and the first intermediate coefficient under each preset operating condition is calculated.

[0037] S102: obtaining currently measured core state parameters, and calculating a second intermediate coefficient based on the currently measured core state parameters by combining the currently measured core state parameters with the first intermediate coefficient;

[0038] The safety-level core state parameter measurement system provides safety-level core state parameters and calculates a second intermediate coefficient under a current operating condition from first intermediate coefficients under multiple sets of transmitted operating conditions.

[0039] S103: obtaining the actual measured current data of the core neutron flux, and calculating the protection parameter LPD by using the actual measured current data of the core neutron flux and the second intermediate coefficient to obtain the protection parameter LPD;

[0040] The core neutron measurement system provides measured current data, which is combined with the second intermediate coefficient based on the current rod position information to realize the rapid calculation of the protection parameter LPD.

[0041] S104: Setting a limit value of a protection parameter LPD, determining a current reactor operation safety margin through the protection parameter LPD and the limit value, and outputting the value of the safety margin.

[0042] The current core operation safety margin is determined based on the relative relationship between the calculated value of the protection parameter LPD and its corresponding limit value.

[0043] Based on the current core safety margin, determine whether a pre-protection / protection signal occurs to implement online protection of the reactor core operation.

[0044] The method and system provided by the present invention mainly include: using the core measurement system detector to provide the measured current, combining the current core measured operating state parameters to realize the rapid calculation of protection parameters, wherein the reactor core operating state parameters include but are not limited to power level, average moderator temperature, primary circuit pressure, control rod position, critical boron concentration and other data, based on the above core operation measured data, to realize the rapid calculation of protection parameters, introduce the real-time measured core operating state parameters as input items for the rapid calculation of protection parameters, and calculate the intermediate parameters based on the current core state. The above method solves the hysteresis problem of the intermediate coefficient used in the calculation of protection parameters in the existing online protection technology, significantly reduces the uncertainty of online protection parameter calculation, improves the accuracy of protection parameter calculation, and has a significant effect on giving full play to the role of online protection technology in improving the operating range of the reactor, further exploring the operational flexibility and economy of nuclear power plant units.

[0045] In an exemplary embodiment of the present invention, obtaining the first intermediate coefficient under a plurality of preset operating conditions includes:

[0046] Establish a three-dimensional geometric model of the core and the material distribution, solve the neutron diffusion equation to simulate the behavior of neutrons in the core, and obtain the spatial and energy distribution of neutrons;

[0047] The first intermediate coefficients are obtained by the spatial and energy distribution of the neutrons.

[0048] In an exemplary embodiment of the present invention, obtaining the second intermediate coefficient based on the currently measured core state parameter includes:

[0049] Establishing a mapping relationship between the first intermediate coefficient and the preset operating condition;

[0050] The second intermediate coefficient is obtained according to the current measured core state parameters.

[0051] In this embodiment, it is assumed that S refn Represents a set of N reactor operating preset conditions, each set of which contains key reactor operating data (such as core power, pressure, temperature, rod position, etc.). The N sets of preset operating conditions are calculated to obtain N first intermediate coefficient values ​​K1, and the mapping relationship K1=f(S refn ), based on this and the current operating conditions of the reactor S mess (Current core power, pressure, temperature, rod position, etc.), determine the corresponding second intermediate coefficient K2.

[0052] In an exemplary embodiment of the present invention, calculating the protection parameter LPD using the measured core neutron flux current data and the second intermediate coefficient includes:

[0053] S=K2*I*P

[0054] Where S is the protection parameter LPD, I is the measured current data of the core neutron flux, K2 is the second intermediate coefficient, and P is the core relative power.

[0055] In a second aspect, the present invention provides a nuclear reactor LPD online protection system, comprising:

[0056] The coefficient determination module is configured to periodically trigger a three-dimensional simulation calculation of the core, simulate the core behavior under a number of preset operating conditions, and obtain a first intermediate coefficient under the plurality of preset operating conditions; obtain currently measured core state parameters, and calculate a second intermediate coefficient based on the currently measured core state parameters by combining the measured core state parameters with the first intermediate coefficient;

[0057] a protection parameter module configured to obtain measured core neutron flux current data, calculate a protection parameter LPD using the measured core neutron flux current data and a second intermediate coefficient to obtain the protection parameter LPD, set a limit value for the protection parameter LPD, determine a current reactor operation safety margin using the protection parameter LPD and the limit value, and output the value of the safety margin;

[0058] The main control device is connected to the coefficient determination module and the protection parameter module, and is used to execute the above-mentioned nuclear reactor LPD online protection method.

[0059] Taking a pressurized water reactor nuclear power plant as an example, this invention requires upgrading the plant's existing core state parameter measurement system to a safety-grade parameter measurement system to implement online core protection. Key inputs, such as core power, average moderator temperature, primary circuit pressure, control rod position, and critical boron concentration, must be safety-grade. This triggers the calculation of intermediate coefficients based on multiple sets of preset operating conditions and transmits them to a protection parameter computer. The integrity and accuracy of the transmitted data are then verified to prevent protection parameter calculation errors caused by data transmission issues, which could affect the implementation of online protection functions.

[0060] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0061] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. The computer software product is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the various embodiments of the present invention. The aforementioned storage medium includes: USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, optical disks, and other media that can store program code.

[0062] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A nuclear reactor LPD online protection method, characterized in that: include: Triggering a three-dimensional simulation calculation of the core periodically to simulate the core behavior under a number of preset operating conditions and obtain the first intermediate coefficients under the preset operating conditions; Acquiring a currently measured core state parameter, and obtaining a second intermediate coefficient based on the currently measured core state parameter by combining the currently measured core state parameter with the first intermediate coefficient; Acquire the measured current data of the core neutron flux, calculate the protection parameter LPD by using the measured current data of the core neutron flux and the second intermediate coefficient, and obtain the protection parameter LPD; A limit value of the protection parameter LPD is set, a current reactor operation safety margin is determined by the protection parameter LPD and the limit value, and the value of the safety margin is output.

2. A nuclear reactor LPD online protection method according to claim 1, characterized in that: The operating conditions include core power, moderator average temperature, primary loop pressure, control rod position and critical boron concentration.

3. A nuclear reactor LPD online protection method according to claim 1, characterized in that: The obtaining of the first intermediate coefficient under a plurality of preset operating conditions comprises: Establish a three-dimensional geometric model of the core and the material distribution, solve the neutron diffusion equation to simulate the behavior of neutrons in the core, and obtain the spatial and energy distribution of neutrons; The first intermediate coefficient is determined by the calculated distribution amount.

4. A nuclear reactor LPD online protection method according to claim 3, characterized in that: The obtaining of the second intermediate coefficient based on the currently measured core state parameter includes: Establishing a mapping relationship between the first intermediate coefficient and the preset operating condition; The current second intermediate coefficient is determined according to the current measured core state parameters.

5. A nuclear reactor LPD online protection method according to claim 4, characterized in that: Calculating the protection parameter LPD using the measured core neutron flux current data and the second intermediate coefficient includes: Where S is the protection parameter LPD, I is the measured current data of the core neutron flux, is the second intermediate coefficient, is the relative power of the core.

6. A nuclear reactor LPD online protection system, characterized in that: include: The coefficient determination module is configured to periodically trigger a three-dimensional simulation calculation of the core, simulate the core behavior under a number of preset operating conditions, and obtain a first intermediate coefficient under the plurality of preset operating conditions; obtain currently measured core state parameters, and calculate a second intermediate coefficient based on the currently measured core state parameters by combining the measured core state parameters with the first intermediate coefficient; a protection parameter module configured to obtain measured core neutron flux current data, calculate a protection parameter LPD using the measured core neutron flux current data and a second intermediate coefficient to obtain the protection parameter LPD, set a limit value for the protection parameter LPD, determine a current reactor operation safety margin using the protection parameter LPD and the limit value, and output the value of the safety margin; A main control device is connected to the coefficient determination module and the protection parameter module, and is used to execute the nuclear reactor LPD online protection method according to any one of claims 1 to 5.

7. A nuclear reactor LPD online protection system according to claim 6, characterized in that: include: The first intermediate coefficient determination module is used to establish a three-dimensional geometric model and material distribution of the core, solve the neutron diffusion equation to simulate the behavior of neutrons in the core, and obtain the spatial and energy distribution of neutrons. The first intermediate coefficient is determined by the calculated distribution amount.

8. A nuclear reactor LPD online protection system according to claim 7, characterized in that: Also includes: a second intermediate coefficient determination module, configured to establish a mapping relationship between the first intermediate coefficient and a preset operating condition; The current second intermediate coefficient is determined according to the current measured core state parameters.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method for online protection of a nuclear reactor LPD according to any one of claims 1 to 5 is implemented.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for online protection of a nuclear reactor LPD according to any one of claims 1 to 5 is implemented.

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