FPGA system reliability guarantee method for nuclear power plant based on radiation effect

Abstract

The application discloses a kind of based on radiation effect's FPGA system reliability guarantee method for nuclear power plant, belong to nuclear power plant control system reliability design technical field.The present application is aimed at different working condition stages under the non-accident state of nuclear power plant, respectively obtains radiation particle environment data, and lays foundation for the accuracy of subsequent evaluation;Second, based on the radiation environment data of each working condition, the most severe working condition of single particle effect and total dose effect is determined first, so as to reduce the scope of subsequent simulation and reduce data processing overhead;Then, the radiation effect under the most severe working condition is simulated by Monte Carlo simulation, and the most sensitive device circuit corresponding to the two effects is directly located, to provide a clear target for reinforcement measures;Finally, based on the reliability determination result of the most sensitive device, a hierarchical processing strategy is used for the most sensitive device circuit to avoid cost waste caused by excessive reinforcement, and finally realize the efficient reliability guarantee of FPGA system cost ratio.

Description

Technical Field

[0001] This invention belongs to the field of reliability design technology for nuclear power plant control systems, and specifically relates to a reliability assurance method for FPGA systems used in nuclear power plants based on radiation effects. Background Technology

[0002] Field-Programmable Gate Arrays (FPGAs) have broad application prospects in the field of nuclear power plant control due to their advantages such as flexible programmability, low power consumption, and strong scalability. They can be used in critical scenarios such as safety control, fuel rod control, reactor power regulation, and shutdown control. However, the nuclear power plant environment contains high-energy radiation particles such as neutrons and gamma rays. Even in non-accident conditions, these radiation particles can have a significant impact on FPGA systems, the most typical of which is the total dose effect of single-event heat transfer.

[0003] Single-event effects, induced by high-energy neutron incidence, can lead to data errors, functional failures, or even complete system crashes in FPGA systems. Total dose effects, caused by long-term gamma-ray irradiation, can increase device leakage current, degrade performance, and in severe cases, cause device failure. Currently, there is a lack of sophisticated methods for assessing the radiation effects of FPGA systems used in nuclear power plants. Existing methods do not fully consider the differences in radiation environments under different operating conditions, resulting in insufficiently targeted and costly hardening measures, making it difficult to achieve cost-effective and reliable designs.

[0004] In summary, existing FPGA system hardening methods lack specificity, resulting in either excessive hardening leading to high costs or insufficient hardening failing to meet reliability requirements. Consequently, existing hardening technologies suffer from either high costs or poor reliability. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a reliability assurance method for FPGA systems used in nuclear power plants based on radiation effects, which addresses the shortcomings of the prior art. The method is novel and reasonable in design, low in cost, highly reliable, and easy to promote and use.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A reliability assurance method for an FPGA system used in nuclear power plants based on radiation effects, comprising the following steps:

[0008] S1. Obtain radiation particle environment data of the FPGA system under different operating conditions in non-accident states; the operating conditions include reactor start-up and low-power operation, full-power operation, refueling and overhaul, shutdown and decommissioning; radiation ion environment data includes energy, flux and duration data of neutrons and gamma rays.

[0009] S2. Based on the data obtained in step S1, determine the most severe single-event effect and the most severe total dose effect conditions respectively.

[0010] S3. Construct a simulation model of the radiation effect of each device circuit in the FPGA system, and perform Monte Carlo simulation for the most severe single-event effect and the most severe total dose effect determined in step S2.

[0011] S4. Based on the Monte Carlo simulation results of step S3, select the most sensitive device circuits for single-event effects in the FPGA system under the most severe single-event effect conditions and the most sensitive device circuits for total dose effects in the FPGA system under the most severe total dose effect conditions.

[0012] S5. Determine the reliability of the most sensitive device circuits selected in step S4, and perform reinforcement or replacement processing according to the determination results.

[0013] S6. After performing the above steps, the FPGA system will be put into use.

[0014] Furthermore, in step S2, the process of determining the most severe single-event effect condition and the most severe total dose effect condition is as follows:

[0015] Based on the energy, flux, and duration of neutrons and gamma rays under different operating conditions, the cumulative flux of neutrons and gamma rays corresponding to different operating conditions is calculated.

[0016] The operating condition corresponding to the maximum cumulative fluence of neutrons is taken as the most severe operating condition of single-event effect, and the operating condition corresponding to the maximum cumulative fluence of gamma rays is taken as the most severe operating condition of total dose effect.

[0017] Furthermore, the process of calculating the cumulative flux of neutrons and gamma rays corresponding to different operating conditions is as follows: each operating condition is divided into N time periods, the neutron energy range is divided into M energy groups, and an N×M neutron flux matrix is ​​constructed. The gamma-ray energy range is divided into M energy groups, and an N×M gamma-ray flux matrix is ​​constructed. ;

[0018] The formula for calculating the cumulative flux of gamma rays is:

[0019]

[0020] in, For the first Time period, number The gamma-ray flux of the energy group, for Operating Condition 1 The energy interval of gamma rays over a period of time. for Operating Condition 1 The duration of gamma rays over a period of time. These are the reactor startup and low-power operation phase, full-power operation phase, refueling and overhaul phase, and shutdown and decommissioning phase.

[0021] The formula for calculating the cumulative flux of neutrons is:

[0022]

[0023] in, For the first Time period, number Neutron flux of the energy group for The first stage of the operating condition neutron duration over a period of time , for Operating Condition 1 The neutron energy interval over a time period.

[0024] Further, in step S3, a Monte Carlo simulation physical model of the FPGA system is constructed, including the size and material data of each device circuit; the neutron energy spectrum of the most severe single-event effect is used as input to perform single-event effect simulation, and the number of single-event effects occurring in each device circuit is recorded; the γ energy spectrum of the most severe total dose effect is used as input to perform total dose effect simulation, and the cumulative total dose of each device circuit is recorded.

[0025] Furthermore, in step S4, the criteria for selecting the most sensitive device circuit are: the device circuit with the most occurrences of single-event effects is the most sensitive device circuit for single-event effects; the device circuit with the largest cumulative total dose is the most sensitive device circuit for total dose effects.

[0026] Furthermore, in step S5, the reliability determination and processing strategy is as follows:

[0027] For the device circuits most sensitive to single-event effects: Based on the number of single-event effects recorded in step S3, calculate the mean time between failures (MTBF) of the device circuit. If the MTBF of the device circuit is greater than the MTBF set by the FPGA system, no hardening or replacement is required. Otherwise, when the time difference is less than 10% of the MTBF set by the FPGA system, redundancy and shielding hardening are used. When the time difference is greater than or equal to 10% of the MTBF set by the FPGA system, replacement is used.

[0028] For the most sensitive device circuit in terms of total dose effect: According to step S3, the cumulative total dose of the most sensitive device circuit is obtained. If the cumulative total dose of the most sensitive device circuit is less than the cumulative total dose set by the FPGA system, no hardening is required; otherwise, when the difference between the two total doses is less than 10% of the cumulative total dose set by the FPGA system, adjustable bias compensation and shielding hardening are adopted; when the difference between the two total doses is greater than or equal to 10% of the cumulative total dose set by the FPGA system, replacement processing is adopted.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention provides a reliability assessment method that combines operational condition differences to accurately identify sensitive devices and formulate optimized hardening strategies. Specifically, it acquires radiation particle environment data for four typical operational stages under non-accident conditions in nuclear power plants, avoiding the shortcomings of existing methods that perform coarse analysis without stage differentiation, thus laying the foundation for the accuracy of subsequent assessments. Secondly, based on the radiation environment data for each operational condition, the most severe operating conditions for single-event effects and total dose effects are first determined, thereby narrowing the scope of subsequent simulations and reducing data processing overhead. Next, Monte Carlo simulation is used to simulate the radiation effects under the most severe operating conditions, directly locating the most sensitive device circuits corresponding to these two types of effects, providing clear targets for hardening measures. Finally, based on the reliability determination results of the most sensitive devices, a graded processing strategy is adopted for the most sensitive device circuits, including no hardening required, targeted hardening, and device replacement, avoiding cost waste caused by over-hardening, and ultimately achieving high-efficiency, cost-effective reliability assurance for FPGA systems. This solves the problems of high hardening costs and unreliability in existing hardening technologies.

[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0032] Figure 1 This is a flowchart illustrating an embodiment of the reliability assurance method for FPGA systems used in nuclear power plants based on radiation effects according to the present invention.

[0033] Figure 2 This is a schematic diagram of the FPGA system structure of an embodiment of the reliability assurance method for FPGA systems used in nuclear power plants based on radiation effects of the present invention. Detailed Implementation

[0034] Example of a reliability assurance method for FPGA systems in nuclear power plants based on radiation effects:

[0035] like Figure 1 As shown, the reliability assurance method for FPGA systems used in nuclear power plants based on radiation effects includes the following steps:

[0036] S1. Acquire radiation particle environment data of the FPGA system under different operating conditions during non-accident periods. Operating conditions include reactor startup and low-power operation, full-power operation, refueling and overhaul, and shutdown and decommissioning. Radiation ion environment data includes neutron and gamma-ray energy, flux, and duration data. Since the focus is primarily on single-event effects and total dose effects, only neutron and gamma-ray related data are acquired. This embodiment obtains real-time neutron and gamma-ray energy, flux, and duration information under different operating conditions through historical nuclear power plant operation data queries and real-time online measurements by the neutron and gamma-ray radiation monitoring system.

[0037] Specifically, when obtaining the radiation ion environment during the reactor startup and low-power operation phases, the neutron energy spectrum and gamma energy spectrum for each time period are obtained based on the reactor physical startup procedure and gamma source term calculation, and the corresponding flux and energy data are obtained based on the energy spectrum.

[0038] When obtaining the radiation ion environment during the full-power operation phase, the radiation field intensity is high but stable during this phase. Therefore, the energy spectrum data in the nuclear power plant's reference radiation environment parameters are used to determine the neutron flux energy spectrum and gamma energy spectrum, as well as a complete fuel cycle, in order to obtain the corresponding energy spectrum, flux, and duration data.

[0039] When acquiring radiation ionization data during refueling and overhaul phases, as well as shutdown and decommissioning phases, since the neutron flux is negligible during these phases, only gamma-ray data need to be obtained. Based on radiation monitoring and historical data from the same phase, data on gamma-ray energy spectrum, flux, and duration are acquired.

[0040] S2. Based on the data obtained in step S1, determine the most severe single-event effect and the most severe total dose effect conditions, respectively, to narrow down the simulation scope of the subsequent step S3.

[0041] In step S2, the process of determining the most severe single-event effect condition and the most severe total dose effect condition is as follows:

[0042] Based on the energy, flux, and duration of neutrons and gamma rays under different operating conditions, the cumulative flux of neutrons and gamma rays corresponding to different operating conditions is calculated.

[0043] The operating condition corresponding to the maximum cumulative neutron fluence is defined as the most severe single-event effect operating condition, and the operating condition corresponding to the maximum cumulative gamma-ray fluence is defined as the most severe total dose effect operating condition. Total dose effect refers to the radiation damage phenomenon caused by the accumulation of ionizing radiation inside semiconductor devices, mainly manifested as the degradation of device electrical performance.

[0044] Specifically, the process of calculating the cumulative flux of neutrons and gamma rays corresponding to different operating conditions is as follows: each operating condition is divided into N time periods, the neutron energy range is divided into M energy groups, and an N×M neutron flux matrix is ​​constructed. The gamma-ray energy range is divided into M energy groups, and an N×M gamma-ray flux matrix is ​​constructed.

[0045] The formula for calculating the cumulative flux of gamma rays is:

[0046]

[0047] in, For the first Time period, number The gamma-ray flux of the energy group, for Operating Condition 1 The energy interval of gamma rays over a period of time. for Operating Condition 1 The duration of gamma rays over a period of time. These are the reactor startup and low-power operation phase, full-power operation phase, refueling and overhaul phase, and shutdown and decommissioning phase.

[0048] The formula for calculating the cumulative flux of neutrons is:

[0049]

[0050] in, For the first Time period, number Neutron flux of the energy group for The first stage of the operating condition neutron duration over a period of time , for Operating Condition 1 The neutron energy interval over a time period.

[0051] Specifically, the cumulative neutron flux is calculated only during reactor startup, low-power operation, and full-power operation, while the cumulative gamma-ray flux is calculated across all operating conditions.

[0052] S3. Construct a simulation model of the radiation effect of each device circuit in the FPGA system, and perform Monte Carlo simulation for the most severe single-event effect and the most severe total dose effect conditions determined in step S2.

[0053] like Figure 2As shown, the device circuitry of the FPGA system includes a clock module for nuclear power plants, a power supply module, an FPGA main chip, a configuration memory module, a memory module, a communication module, an AD / DA module, an image processing and display module, and an I / O module.

[0054] In step S3, constructing the Monte Carlo simulation physical model of the FPGA system requires extracting the physical structure information of each device circuit, including the thickness of each layer, material information, length and width of metal and non-metal lines in the core functional circuits, and sensitive volume dimensions. In other words, this physical model contains the dimensions and material data of each device circuit, ensuring that the model accurately reflects the radiation response characteristics of the devices.

[0055] Monte Carlo simulation process: The neutron energy spectrum under the most severe single-event effect condition is used as input for single-event effect simulation, recording the number of single-event effect occurrences for each device circuit; the gamma energy spectrum under the most severe total dose effect condition is used as input for total dose effect simulation, recording the cumulative total dose for each device circuit. Monte Carlo simulation simulates the interaction between radiating particles and devices through numerous random experiments, accurately obtaining the radiation response data of the devices.

[0056] S4. Based on the Monte Carlo simulation results of step S3, select the most sensitive device circuits for single-event effects in the FPGA system under the most severe single-event effect conditions and the most sensitive device circuits for total dose effects in the FPGA system under the most severe total dose effect conditions.

[0057] Specifically, the criteria for selecting the most sensitive device circuits are as follows: the device circuit with the highest number of single-event effects is the most sensitive to single-event effects; because the device circuit with the highest number of single-event effects is most prone to failure due to neutron incidence under the most severe operating conditions. The device circuit with the highest cumulative total dose is the most sensitive to total dose effects; because the device circuit with the highest cumulative total dose is most prone to performance degradation due to cumulative gamma-ray irradiation under the most severe operating conditions.

[0058] S5. Determine the reliability of the most sensitive device circuits selected in step S4, and perform reinforcement or replacement processing according to the determination results.

[0059] In step S5, the reliability determination and handling strategy is as follows:

[0060] For the device circuits most sensitive to single-event effects: Based on the number of single-event effects recorded in step S3, calculate the mean time between failures (MTBF) of the device circuit. If the MTBF > the MTBF set by the FPGA system, no hardening or replacement is required. Otherwise, when the time difference is < 10% of the MTBF set by the FPGA system, redundancy and shielding hardening are used; when the time difference is ≥ 10% of the MTBF set by the FPGA system, replacement is used. Here, the time difference refers to the difference between the device circuit's MTBF and the FPGA system's MTBF. When the MTBF > the FPGA system's MTBF, the device reliability meets the requirements, no hardening is needed, and the entire FPGA system can be directly applied. The redundancy processing here uses multi-mode redundancy to improve fault tolerance, and shielding materials block some neutron incidence.

[0061] For the most sensitive device circuit in terms of total dose effect: Based on step S3, the cumulative total dose of the most sensitive device circuit is obtained. If the cumulative total dose of the most sensitive device circuit is less than the cumulative total dose set by the FPGA system, no hardening is required; otherwise, when the difference between the two total doses is less than 10% of the cumulative total dose set by the FPGA system, adjustable bias compensation and shielding hardening are used; when the difference between the two total doses is greater than or equal to 10% of the cumulative total dose set by the FPGA system, replacement processing is used. The difference between the two total doses refers to the difference between the cumulative total dose of the most sensitive device circuit and the cumulative total dose set by the FPGA system.

[0062] S6. After performing the above steps, the FPGA system will be put into use.

[0063] This invention solves the problem of reliability assessment of FPGA systems used in nuclear power plants under strong radiation environments through refined radiation environment analysis, accurate identification of sensitive devices, and optimized hardening strategies.

[0064] The above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Any simple modifications, alterations, or equivalent structural changes made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A method for ensuring the reliability of an FPGA system for nuclear power plants based on radiation effects, characterized in that it comprises the steps of: The method comprises the following steps: ​ S1, obtaining radiation particle environment data of the FPGA system in different working condition stages under a non-accident state; the working condition stages comprise a reactor startup and low-power operation stage, a full-power operation stage, a refueling and overhaul stage, and a shutdown and decommissioning stage; the radiation ion environment data comprises energy, flux, and duration data of neutrons and gamma rays; S2, determining a single event effect most severe working condition and a total dose effect most severe working condition respectively according to the data obtained in step S1; In step S2, the process of determining the single event effect most severe working condition and the total dose effect most severe working condition is as follows: According to the energy, flux, and duration of neutrons and gamma rays in different working condition stages, the cumulative fluence of neutrons and gamma rays corresponding to different working condition stages is calculated; The working condition stage corresponding to the maximum cumulative fluence of neutrons is taken as the single event effect most severe working condition, and the working condition stage corresponding to the maximum cumulative fluence of gamma rays is taken as the total dose effect most severe working condition; S3, constructing a radiation effect simulation model of each device circuit in the FPGA system, and performing Monte Carlo simulation for the single event effect most severe working condition and the total dose effect most severe working condition determined in step S2 respectively; S4, screening a single event effect most sensitive device circuit of the FPGA system under the single event effect most severe working condition and a total dose effect most sensitive device circuit of the FPGA system under the total dose effect most severe working condition according to the Monte Carlo simulation results of step S3; S5, performing reliability determination on the most sensitive device circuits screened in step S4, and performing reinforcement or replacement treatment according to the determination results; S6, after the above steps are performed, the FPGA system is put into use.

2. The method for ensuring the reliability of the FPGA system for nuclear power plants based on the radiation effect according to claim 1, characterized in that: The process of calculating the cumulative neutron and gamma ray fluences corresponding to different working condition stages is as follows: dividing each working condition stage into N time periods, dividing the neutron energy range into M energy groups, constructing an N*M neutron flux matrix ; dividing the gamma ray energy range into M energy groups, and constructing an N*M gamma ray flux matrix ; The formula for calculating the cumulative fluence of gamma rays is: in, For the first Time period, number The gamma-ray flux of the energy group, for Operating Condition 1 The energy interval of gamma rays over a period of time. for Operating Condition 1 The duration of gamma rays over a period of time. These are the reactor startup and low-power operation phase, full-power operation phase, refueling and overhaul phase, and shutdown and decommissioning phase. The formula for calculating the cumulative fluence of neutrons is: wherein, is a first time period, neutron flux of the energy group, is a first neutron duration of the time period, , is a first neutron energy interval of the time period.

3. The method for ensuring the reliability of the FPGA system for nuclear power plants based on the radiation effect according to claim 1, characterized in that: In step S3, a Monte Carlo simulation physical model of the FPGA system is constructed, which contains the size and material data of each device circuit; the neutron energy spectrum of the single event effect most severe working condition is taken as the input for single event effect simulation, and the number of times of single event effect of each device circuit is recorded; the gamma energy spectrum of the total dose effect most severe working condition is taken as the input for total dose effect simulation, and the cumulative total dose of each device circuit is recorded.

4. The method for ensuring the reliability of a FPGA system for nuclear power plants based on radiation effects according to claim 3, characterized in that: In step S4, the standard for screening the most sensitive device circuit is that: the device circuit with the most number of times of single event effect is the single event effect most sensitive device circuit; and the device circuit with the maximum cumulative total dose is the total dose effect most sensitive device circuit.

5. The method for ensuring the reliability of a FPGA system for nuclear power plants based on radiation effects according to claim 4, characterized in that: In step S5, the reliability determination and treatment strategy are as follows: For the single event effect most sensitive device circuit: according to the number of times of single event effect of each device circuit recorded in step S3, the mean time between failures of the device circuit is calculated; if the mean time between failures of the device circuit is greater than the mean time between failures set for the FPGA system, no reinforcement and replacement treatment is needed; otherwise, when the time difference is less than 10% of the mean time between failures set for the FPGA system, redundancy and shielding reinforcement treatment is adopted; and when the time difference is greater than or equal to 10% of the mean time between failures set for the FPGA system, replacement treatment is adopted. The most sensitive device circuit to total dose effect is obtained according to step S3, and if the accumulated total dose of the most sensitive device circuit is less than the accumulated total dose set by the FPGA system, no reinforcement is needed; otherwise, when the total dose difference is less than 10% of the accumulated total dose set by the FPGA system, adjustable bias compensation and shielding reinforcement are adopted; When the total dose difference is greater than or equal to 10% of the accumulated total dose set by the FPGA system, replacement processing is adopted.

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