Nuclear reactor LPD online protection method and system

Abstract

The invention relates to the technical field of nuclear safety, in particular to a nuclear reactor LPD online protection method and a nuclear reactor LPD online protection system, which mainly comprise the following steps: providing actually measured current by using a reactor core measurement system detector, and realizing rapid calculation of protection parameters by combining the actually measured running state parameters of the current reactor core. The method comprises the following steps: introducing real-time actually-measured reactor core operation state parameters as input items for quickly calculating protection parameters, and calculating intermediate parameters based on a current reactor core state; by means of the method, the problem of hysteresis of the intermediate coefficient used in protection parameter calculation in an existing online protection technology is solved, the uncertainty of online protection parameter calculation is remarkably reduced, the protection parameter calculation precision is improved, the reactor operation range is remarkably improved by exerting the online protection technology, and the method is suitable for popularization and application. And the operation flexibility and economy of nuclear power plant units are further explored.

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] During the operation of a pressurized water reactor, in order to prevent the melting of fuel assemblies, the temperature of the fuel cladding is required to be below a certain limit temperature, that is, the core LPD (linear power density) during the operation of the reactor is limited, and the maximum LPD value of the whole reactor is required to be below a certain limit. In the existing pressurized water reactors, the above-mentioned core protection parameters (LPD) are mainly limited by setting the operation diagram, overtemperature ΔT and overpower ΔT protection to achieve core operation protection. Pressurized water reactors achieve core protection by setting the operation diagram, overtemperature ΔT and overpower ΔT channels. The operation diagram, overtemperature ΔT and overpower ΔT channels will limit the operating range and operating flexibility of the reactor, affecting the economic efficiency of the reactor operation.

[0003] The online protection technology for pressurized water reactors can obtain the neutron flux data in the reactor in real time by setting up a core measurement system in the reactor. Based on the core measurement system, the online calculation of the protection parameters of the entire reactor can be realized, thereby realizing the online protection of the reactor. However, in the existing online protection technology, due to the obvious hysteresis of the intermediate coefficients used in the calculation of the protection parameters, there is a large uncertainty in the existing online protection system. The operating range expanded by the online protection system is compressed by the large system uncertainty, resulting in the existing online protection technology not significantly improving the reactor operating range. Summary of the invention

[0004] The object 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 the three-dimensional simulation calculation of the core periodically to simulate the core behavior under several preset operating conditions and obtain the first intermediate coefficient under several preset operating conditions;

[0008] Acquire the currently measured core state parameter, and calculate the 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, the 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 loop pressure, control rod position or critical boron concentration.

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

[0013] 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;

[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 current data of the core neutron flux 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 trigger the three-dimensional simulation calculation of the core periodically, simulate the core behavior under several preset operating conditions, and obtain the first intermediate coefficient under several preset operating conditions; obtain the currently measured core state parameters, and calculate the 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 is configured to obtain the measured current data of the core neutron flux, calculate the protection parameter LPD through the measured current data of the core neutron flux and the second intermediate coefficient, obtain the protection parameter LPD, set a limit value of the protection parameter LPD, determine the current reactor operation safety margin through 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 solution of the embodiment of the present invention has 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 measured current, and realizing rapid calculation of protection parameters in combination with the current measured core operating state 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-mentioned core operation measured data, rapid calculation of protection parameters is realized, and real-time measured core operating state parameters are introduced as input items for rapid calculation of protection parameters, and intermediate parameters based on the current core state are calculated. 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 operation range by giving full play to online protection technology, further exploring the flexibility and economy of nuclear power plant unit operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without 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 clearer, the technical solutions of the embodiments of the present invention will be described clearly and completely in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 here can be arranged and designed in various different configurations.

[0030] The terms "first, second" and the like in the specification and claims of this application and the above 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 mean that the steps in the method flow must be executed in the time / logical sequence indicated by the naming or numbering. The named or numbered process steps can be changed in the execution order according to the technical purpose to be achieved, as long as the same or similar technical effects can be achieved.

[0031] The modules or submodules described independently may be physically separated or not: they may be implemented by software or hardware, and some modules or submodules may be implemented by software, and the processor may call the software to implement the functions of these modules or submodules, and other modules or submodules may be implemented by hardware, such as by hardware circuits. In addition, some or all of the modules may be selected according to actual needs to achieve the purpose 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 obtaining a first intermediate coefficient under a number of preset operating conditions;

[0034] Upgrade the reactor core state parameter measurement system to the 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 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;

[0038] The safety-level core state parameter measurement system provides safety-level core state parameters, and calculates a second intermediate coefficient under current operating conditions from the first intermediate coefficients under the transmitted multiple sets of 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 the protection parameter LPD, determining the 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] According to the current core safety margin, it is determined whether a pre-protection / protection signal occurs, so as to realize 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 measured current, combining the current core measured operating state parameters to realize 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 rapid calculation of protection parameters, introduce real-time measured core operating state parameters as input items for rapid calculation of protection parameters, and calculate 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 reactor operation range, and further explores the flexibility and economy of nuclear power plant unit operation.

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

[0046] 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;

[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, the obtaining of the second intermediate coefficient based on the currently measured core state parameter comprises:

[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 operation preset conditions, each set of preset conditions contains key reactor operation data (such as core power, pressure, temperature, rod position, etc.), and N sets of preset operation conditions are respectively calculated to obtain N first intermediate coefficient values ​​K1, and the mapping relationship K1=f(S refn ), based on this combined with 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, the calculation of the protection parameter LPD using the measured current data of the core neutron flux 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 trigger the three-dimensional simulation calculation of the core periodically, simulate the core behavior under several preset operating conditions, and obtain the first intermediate coefficient under several preset operating conditions; obtain the currently measured core state parameters, and calculate the 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 is configured to obtain the measured current data of the core neutron flux, calculate the protection parameter LPD through the measured current data of the core neutron flux and the second intermediate coefficient, obtain the protection parameter LPD, set a limit value of the protection parameter LPD, determine the current reactor operation safety margin through 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] The present invention takes a pressurized water reactor nuclear power plant as an example. It is necessary to upgrade the existing core state parameter measurement system of the nuclear power plant to a safety-level parameter measurement system to realize core online protection. The core power, average moderator temperature, primary circuit pressure, control rod position, critical boron concentration and other information as the main input items must be of safety level. The calculation of intermediate coefficients based on multiple sets of preset operating conditions is triggered and transmitted to the protection parameter computer to verify the integrity and accuracy of the transmitted data, so as to prevent the calculation errors of protection parameters caused by data transmission problems and affect the realization of online protection functions.

[0060] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0061] If the integrated unit is implemented in the form of 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, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of various embodiments of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0062] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A nuclear reactor LPD online protection method, characterized in that: include: Triggering the three-dimensional simulation calculation of the core periodically to simulate the core behavior under several preset operating conditions and obtain the first intermediate coefficient under several preset operating conditions; Acquire the currently measured core state parameter, and obtain 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, the 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, average moderator 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 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.

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 comprises: 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: The calculation of the protection parameter LPD using the measured current data of the core neutron flux and the second intermediate coefficient includes: S=K2*I*P 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.

6. A nuclear reactor LPD online protection system, characterized in that: include: The coefficient determination module is configured to trigger the three-dimensional simulation calculation of the core periodically, simulate the core behavior under several preset operating conditions, and obtain the first intermediate coefficient under several preset operating conditions; obtain the currently measured core state parameters, and calculate the 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 is configured to obtain the measured current data of the core neutron flux, calculate the protection parameter LPD through the measured current data of the core neutron flux and the second intermediate coefficient, obtain the protection parameter LPD, set a limit value of the protection parameter LPD, determine the current reactor operation safety margin through 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 a nuclear reactor LPD online protection method as described in any one of claims 1-5.

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, used 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, a method for online protection of a nuclear reactor LPD according to any one of claims 1 to 8 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 8 is implemented.

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