Online protection method and system

Abstract

The present invention relates to an online protection method and system, which comprises: obtaining regularly updated calibration state data; reconstructing and calculating the core power distribution data corresponding to each control rod total rod position according to the calibration state core parameter data corresponding to each control rod total rod position; obtaining the current control rod total rod position in real time, and selecting a group of core power distribution data from multiple groups of core power distribution data as the current core power distribution data according to the current control rod total rod position; calculating the LPD maximum value and DNBR minimum value corresponding to the current control rod total rod position according to the current core power distribution data; judging whether to trigger the shutdown signal according to the calculated LPD maximum value and DNBR minimum value, as well as the preset LPD setting value and DNBR setting value. By implementing the technical solution of the present invention, this method can not only reduce the calculation uncertainty, but also improve the response speed of protection.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power design, and in particular to an online protection method and system. Background Art

[0002] To ensure reactor safety, the design requires that the maximum heat flux density on the fuel assembly surface be less than the critical heat flux density, thus introducing DNBR (Departure from Nucleate Boiling Ratio) protection. At the same time, in order to avoid excessive core linear power density, LPD (Linear Power Density) protection is introduced.

[0003] In addition to being related to the main pump speed, cold section temperature, and coolant pressure, DNBR and LPD calculations are also related to core power distribution data. Moreover, core power distribution monitoring is crucial to the safe operation of the reactor. At present, pressurized water reactors generally detect core neutron flux through neutron detectors, and then regularly calculate core power distribution in combination with external nuclear instrument monitoring data. However, this method does not have high enough calculation accuracy and a slow response time, making it impossible to achieve good LPD and DNBR protection functions. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method and system for online protection in view of the defects of the prior art that the calculation accuracy is low and the response time is slow.

[0005] The technical solution adopted by the present invention to solve the technical problem is: constructing an online protection method for reactor LPD and DNBR protection, comprising:

[0006] Step S10. Obtaining regularly updated calibration state data, wherein the calibration state data includes a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod total rod positions;

[0007] Step S20. Reconstruct and calculate the core power distribution data corresponding to each control rod total position according to the calibrated core parameter data corresponding to each control rod total position;

[0008] Step S30. Acquire the current total control rod position in real time, and select a set of core power distribution data from multiple sets of core power distribution data as the current core power distribution data according to the current total control rod position;

[0009] Step S40. Calculate the maximum LPD value and the minimum DNBR value corresponding to the current total control rod position according to the current core power distribution data;

[0010] Step S50: Determine whether to trigger a shutdown signal based on the calculated maximum LPD value and minimum DNBR value, as well as the preset LPD setting value and DNBR setting value.

[0011] Preferably, in step S30, the current core power distribution data is obtained in the following manner:

[0012] Subtract the multiple total control rod positions in the calibration state data from the current total control rod position, and take a group of core power distribution data corresponding to the total control rod position with the smallest positive difference as the current core power distribution data.

[0013] Preferably, the step S50 includes:

[0014] Determine whether the calculated LPD maximum value is greater than a preset LPD setting value;

[0015] Determine whether the calculated DNBR minimum value is less than the preset DNBR setting value;

[0016] If the LPD maximum value is greater than the LPD set value, or the DNBR minimum value is less than the DNBR set value, a shutdown signal is triggered.

[0017] Preferably, in step S10, the calibration state data is obtained according to the following method:

[0018] The calibration state data is obtained by regularly performing three-dimensional simulations on the operation of the reactor at various calibration states.

[0019] Preferably, in step S10, the calibration state data is obtained according to the following method:

[0020] The calibration state data is obtained by testing the operation of the reactor in various calibration states.

[0021] Preferably, in step S10, the calibration state data is obtained according to the following method:

[0022] When the reactor is operating in various calibration states, the core neutron flux is detected by multiple neutron detectors arranged in the reactor.

[0023] The present invention also constructs an online protection system for reactor LPD and DNBR protection, comprising:

[0024] An acquisition module, used for acquiring regularly updated calibration state data, wherein the calibration state data includes a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod positions;

[0025] A power reconstruction module is used to reconstruct and calculate the core power distribution data corresponding to each control rod total rod position according to the calibrated core parameter data corresponding to each control rod total rod position;

[0026] A determination module is used to obtain the current total control rod position in real time, and select a group of core power distribution data from multiple groups of core power distribution data as the current core power distribution data according to the current total control rod position;

[0027] A calculation module, used for calculating the maximum LPD value and the minimum DNBR value corresponding to the current total control rod position according to the current core power distribution data;

[0028] The judgment module is used to judge whether to trigger the shutdown signal according to the calculated LPD maximum value and DNBR minimum value, as well as the preset LPD setting value and DNBR setting value.

[0029] Preferably, the determination module is used to subtract the multiple total control rod positions in the calibration state data from the current total control rod position, and take a group of core power distribution data corresponding to the total control rod position with the smallest positive difference as the current core power distribution data.

[0030] Preferably, the judging module comprises:

[0031] A first judging subunit, used to judge whether the calculated LPD maximum value is greater than a preset LPD setting value;

[0032] The second judgment subunit is used to judge whether the calculated DNBR minimum value is less than the preset DNBR setting value;

[0033] The shutdown triggering unit is used to trigger a shutdown signal when the LPD maximum value is greater than the LPD set value, or when the DNBR minimum value is less than the DNBR set value.

[0034] Preferably, the acquisition module is used to acquire calibration state data by regularly performing three-dimensional simulation or testing on the operation of the reactor in various calibration states.

[0035] In the technical solution provided by the present invention, after obtaining the regularly updated calibration state data (multiple groups of calibration state core parameter data corresponding to multiple different control rod total rod positions), different full core power distributions are reconstructed in segments according to different control rod total rod positions, and then a group of full core power distribution data is selected from the multiple groups of full core power distribution data according to the real-time total rod position at site, and then the real-time maximum LPD value and minimum DNBR value are determined in real time. This method can not only reduce the calculation uncertainty, but also improve the response speed of protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0037] Figure 1 is a flow chart of Embodiment 1 of the online protection method of the present invention;

[0038] Figure 2 is a flow chart of Embodiment 2 of the online protection method of the present invention;

[0039] Figure 3 It is a logical structure diagram of the first embodiment of the online protection system of the present invention. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] First of all, it should be noted that the control rod, as a tool for rapid control of reactivity, can adjust the power of the reactor during normal operation, and quickly introduce negative reactivity under accident conditions to quickly shut down the reactor. Experiments have shown that the total rod position of the control rod also affects the power distribution of the reactor. Based on this, in the technical solution of the present application, firstly, according to different total number of control rod insertion steps, different full-core power distributions are reconstructed in sections, and then a section of the reconstructed full-core power distribution is selected according to the total rod position on site, and then the LPD and DNBR values ​​are determined in real time on site. This method can reduce calculation uncertainty, improve the response speed of protection, and obtain more safety margins.

[0042] Figure 1 1 is a flow chart of Embodiment 1 of the online protection method of the present invention. The online protection method of this embodiment is used for reactor LPD and DNBR protection and includes the following steps:

[0043] Step S10. Obtaining regularly updated calibration state data, wherein the calibration state data includes a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod total rod positions;

[0044] In this step, the calibration state data is the core parameter data under steady-state conditions, and there are multiple groups of calibration state data, corresponding to different total rod positions, for example, Figure 2 , the calibration state core parameter data when the total rod position is R1; the calibration state core parameter data when the total rod position is R2; the calibration state core parameter data when the total rod position is R3; the calibration state core parameter data when the total rod position is R4. It should be understood that the more groups the core parameter data is divided into, the more accurate the calculation is, but it also increases the amount of calculation. Therefore, engineering generally makes a trade-off, for example, obtaining three groups of calibration state core parameter data corresponding to the three total rod positions.

[0045] Regarding the method of obtaining calibration state data, in a specific example, the calibration state data can be obtained by regularly performing three-dimensional simulations on the operation of the reactor in various calibration states; in another specific example, the calibration state data can be obtained by testing the operation of the reactor in various calibration states, and when the reactor is operating in various calibration states, the core neutron flux is detected by multiple neutron detectors arranged in the reactor, and the core flux diagram is calculated based on the core neutron flux.

[0046] In addition, it should be noted that the calibration state data can be generated or updated by the upper computer (non-security-level device) and regularly transmitted to the lower computer (security-level device), that is, the lower computer obtains the regularly updated calibration state data from the upper computer and then executes steps S20 to S50.

[0047] Step S20. Reconstruct and calculate the core power distribution data corresponding to each control rod total position according to the calibrated core parameter data corresponding to each control rod total position;

[0048] In this step, when performing the reconstruction calculation of the core power distribution data, the weight coefficient method, the coupling coefficient method or the harmonic synthesis method can be used, and different full core power distribution data can be reconstructed according to the calibration state core parameter data corresponding to different total rod positions. For example, Figure 2 According to the calibrated core parameter data at the total rod position R1, the full core power distribution corresponding to the total rod position R1 is reconstructed; according to the calibrated core parameter data at the total rod position R2, the full core power distribution corresponding to the total rod position R2 is reconstructed; according to the calibrated core parameter data at the total rod position R3, the full core power distribution corresponding to the total rod position R3 is reconstructed; according to the calibrated core parameter data at the total rod position R4, the full core power distribution corresponding to the total rod position R4 is reconstructed.

[0049] Step S30. Acquire the current total control rod position in real time, and select a set of core power distribution data from multiple sets of core power distribution data as the current core power distribution data according to the current total control rod position;

[0050] In this step, it should be noted that the rod position measurement signals of each rod of the control rod can be obtained from the measuring mechanism, so as to obtain the current total rod position of the control rod. After obtaining the current total rod position of the control rod, then select a set of core power distribution data from multiple sets of core power distribution data according to the current sub-rod position, and use it as the current core power distribution data.

[0051] Step S40. Calculate the maximum LPD value and the minimum DNBR value corresponding to the current total rod position of the control rod according to the current core power distribution data;

[0052] In this step, after determining the current core power distribution data, the LPD values and DNBR values of each occurrence point of each fuel assembly at the current total rod position can be calculated by using the current core power distribution data. It should be understood that the calculation methods of LPD and DNBR are both existing methods and will not be elaborated here. Then, determine the maximum LPD value from the calculated multiple LPD values, and determine the minimum DNBR value from the calculated multiple DNBR values. For example, if a certain core has 177 fuel assemblies and each assembly has 44 occurrence points, then 177 * 44 LPD values and 177 * 44 DNBR values will be generated.

[0053] Step S50. Determine whether to trigger a reactor trip signal according to the calculated maximum LPD value and minimum DNBR value, and the preset LPD set value and DNBR set value.

[0054] In this step, it should be noted that the LPD set value and the DNBR set value are both set in advance according to the accident analysis results.

[0055] Furthermore, in a specific embodiment, in step S30, the current core power distribution data can be obtained in the following manner: subtract the multiple total rod positions of the control rod in the calibrated state data from the current total rod position of the control rod respectively, and use the set of core power distribution data corresponding to the total rod position of the control rod with the smallest positive difference as the current core power distribution data. For example, combined with Figure 2 , assuming that at a certain moment, the current total rod position of the core control rod is R, if 0 ≤ R ≤ R1, select the core power distribution data corresponding to the total rod position R1 to calculate the minimum DNBR value and the maximum LPD value; if R1 < R ≤ R2, select the core power distribution data corresponding to the total rod position R2 to calculate the minimum DNBR value and the maximum LPD value; if R2 < R ≤ R3, select the core power distribution data corresponding to the total rod position R3 to calculate the minimum DNBR value and the maximum LPD value; if R3 < R ≤ R4, select the core power distribution data corresponding to the total rod position R4 to calculate the minimum DNBR value and the maximum LPD value.

[0056] Furthermore, in a specific embodiment, combined with Figure 2, step S50 comprises:

[0057] Determine whether the calculated LPD maximum value is greater than a preset LPD setting value;

[0058] Determine whether the calculated DNBR minimum value is less than the preset DNBR setting value;

[0059] If the LPD maximum value is greater than the LPD set value, or the DNBR minimum value is less than the DNBR set value, a shutdown signal is triggered.

[0060] Figure 3 1 is a logical structure diagram of an embodiment 1 of an online protection system of the present invention, the online protection system is used for reactor LPD and DNBR protection, and comprises: an acquisition module 10, a power reconstruction module 20, a determination module 30, a calculation module 40 and a judgment module 50, wherein the acquisition module 10 is used to acquire regularly updated calibration state data, wherein the calibration state data comprises a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod total rod positions; the power reconstruction module 20 is used to calculate the calibration state core parameter data corresponding to each control rod total rod position according to the calibration state core parameter data corresponding to each control rod total rod position; The core power distribution data is reconstructed and calculated; the determination module 30 is used to obtain the current control rod total rod position in real time, and select a group of core power distribution data from multiple groups of core power distribution data as the current core power distribution data according to the current control rod total rod position; the calculation module 40 is used to calculate the LPD maximum value and DNBR minimum value corresponding to the current control rod total rod position according to the current core power distribution data; the judgment module 50 is used to judge whether to trigger the shutdown signal according to the calculated LPD maximum value and DNBR minimum value, as well as the preset LPD setting value and DNBR setting value.

[0061] Furthermore, the acquisition module 10 is used to acquire calibration state data by regularly performing three-dimensional simulation or testing on the operation of the reactor in various calibration states.

[0062] Further, the determination module 30 is used to subtract the multiple control rod total positions in the calibration state data from the current control rod total position, and take a set of core power distribution data corresponding to the control rod total position with the smallest positive difference as the current core power distribution data.

[0063] Furthermore, the judgment module 40 includes a first judgment subunit, a second judgment subunit and a shutdown trigger unit, wherein the first judgment subunit is used to judge whether the calculated LPD maximum value is greater than the preset LPD setting value; the second judgment subunit is used to judge whether the calculated DNBR minimum value is less than the preset DNBR setting value; and the shutdown trigger unit is used to trigger a shutdown signal when the LPD maximum value is greater than the LPD setting value, or the DNBR minimum value is less than the DNBR setting value.

[0064] The above description is only a preferred embodiment of the present invention and is 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 substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. An online protection method for reactor LPD and DNBR protection, characterized in that: include: Step S10. Obtaining regularly updated calibration state data, wherein the calibration state data includes a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod positions; Step S20. Reconstruct and calculate the core power distribution data corresponding to each control rod total position according to the calibrated core parameter data corresponding to each control rod total position; Step S30. Acquire the current total control rod position in real time, and select a set of core power distribution data from multiple sets of core power distribution data as the current core power distribution data according to the current total control rod position; Step S40. Calculate the maximum LPD value and the minimum DNBR value corresponding to the current total control rod position according to the current core power distribution data; Step S50: Determine whether to trigger a shutdown signal based on the calculated maximum LPD value and minimum DNBR value, as well as the preset LPD setting value and DNBR setting value.

2. The online protection method according to claim 1, characterized in that: In step S30, the current core power distribution data is determined according to the following method: Subtract the multiple total control rod positions in the calibration state data from the current total control rod position, and take a group of core power distribution data corresponding to the total control rod position with the smallest positive difference as the current core power distribution data.

3. The online protection method according to claim 1, characterized in that: The step S50 comprises: Determine whether the calculated LPD maximum value is greater than a preset LPD setting value; Determine whether the calculated DNBR minimum value is less than the preset DNBR setting value; If the LPD maximum value is greater than the LPD set value, or the DNBR minimum value is less than the DNBR set value, a shutdown signal is triggered.

4. The online protection method according to claim 1, characterized in that: In step S10, the calibration state data is obtained according to the following method: The calibration state data is obtained by regularly performing three-dimensional simulations on the operation of the reactor at various calibration states.

5. The online protection method according to claim 1, characterized in that: In step S10, the calibration state data is obtained according to the following method: The calibration state data is obtained by testing the operation of the reactor in various calibration states.

6. The online protection method according to claim 5, characterized in that: In step S10, the calibration state data is obtained according to the following method: When the reactor is operating in various calibration states, the core neutron flux is detected by multiple neutron detectors arranged in the reactor.

7. An online protection system for reactor LPD and DNBR protection, characterized in that: include: An acquisition module, used for acquiring regularly updated calibration state data, wherein the calibration state data includes a plurality of groups of calibration state core parameter data corresponding to a plurality of different control rod positions; A power reconstruction module is used to reconstruct and calculate the core power distribution data corresponding to each control rod total rod position according to the calibrated core parameter data corresponding to each control rod total rod position; A determination module is used to obtain the current total control rod position in real time, and select a group of core power distribution data from multiple groups of core power distribution data as the current core power distribution data according to the current total control rod position; A calculation module, used for calculating the maximum LPD value and the minimum DNBR value corresponding to the current total control rod position according to the current core power distribution data; The judgment module is used to judge whether to trigger the shutdown signal according to the calculated LPD maximum value and DNBR minimum value, as well as the preset LPD setting value and DNBR setting value.

8. The online protection system according to claim 7, characterized in that: The determination module is used to subtract the multiple total control rod positions in the calibration state data from the current total control rod position, and use a group of core power distribution data corresponding to the total control rod position with the smallest positive difference as the current core power distribution data.

9. The online protection system according to claim 7, characterized in that: The judging module comprises: A first judging subunit, used to judge whether the calculated LPD maximum value is greater than a preset LPD setting value; The second judgment subunit is used to judge whether the calculated DNBR minimum value is less than the preset DNBR setting value; The shutdown triggering unit is used to trigger a shutdown signal when the LPD maximum value is greater than the LPD set value, or when the DNBR minimum value is less than the DNBR set value.

10. The online protection system according to claim 7, characterized in that: The acquisition module is used to acquire calibration state data by regularly performing three-dimensional simulation or testing on the operation of the reactor in various calibration states.

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