Fuel rod PCI (Peripheral Component Interconnect) critical power determination method and device and computer equipment

Abstract

The invention discloses a fuel rod PCI critical power determination method and device and computer equipment. The method comprises the following steps: acquiring expected power of a fuel rod in a nuclear reactor core in each operation stage in a life cycle; determining target power and target burnup of the fuel rod in a stable state according to the expected power; and performing transient change on the target power according to a limiting condition corresponding to the cladding type of the fuel rod, and determining the PCI critical power of the fuel rod under the target power and the target burnup operation. The PCI critical powers of different fuel rods under different operation powers and burnups are determined, the reliability and comprehensiveness of PCI performance analysis of the fuel rods are improved, actual operation of the fuel rods can be adjusted and controlled, and PCI performance failure of the fuel rods is avoided.

Description

Technical Field

[0001] The present application relates to the field of nuclear reactor application technology, and in particular to a method, device and computer equipment for determining the PCI critical power of a fuel rod. Background Art

[0002] The fuel rod is one of the core components of a nuclear reactor, and its structural integrity is related to the safe operation of the entire nuclear reactor. The fuel rod consists of a cladding tube, a fuel pellet, a gas cavity spring, and upper and lower end plugs. In the initial design, a certain gap is left between the fuel pellet and the cladding tube to accommodate the deformation of the fuel pellet.

[0003] During the operation of a nuclear reactor, the fuel pellets are affected by radiation and thermal effects, and will swell and expand outward due to radiation, while the cladding will creep inward under the combined effect of the coolant external pressure and the fuel rod internal pressure. In the middle and late stages of nuclear reactor operation, under the combined effect of the long-term radiation swelling and thermal expansion of the fuel pellets and the inward creep of the cladding, the gap between the fuel pellets and the cladding will be reduced to zero and contact will occur. This phenomenon is called Pellet-Cladding Interaction (PCI).

[0004] Under transient conditions during the operation of a nuclear reactor, due to the rapid increase in the power of the nuclear reactor, the fuel pellets will produce a greater thermal expansion effect than in normal operation, which will cause the cladding to produce greater stress and strain during the PCI process and exceed the failure limit, causing the cladding to fail and no longer have the ability to contain fission products, and affecting the operating safety of the nuclear reactor.

[0005] In the related art, in order to avoid cladding failure, fuel rods with typical characteristics or specific features are selected from each fuel assembly in the core, and the PCI performance of these fuel rods is analyzed based on the data at the beginning of the design of the selected fuel rods. However, the PCI performance of fuel rods other than those selected in the core and the power fluctuations involved in the actual operation of the fuel rods cannot be fully considered. Summary of the invention

[0006] In view of this, the present application provides a method, device and computer equipment for determining the PCI critical power of a fuel rod. Through the restriction conditions corresponding to the expected power of the fuel rod and the cladding type, the PCI critical power of the fuel rod when a transient occurs at different operating powers and fuel consumptions is determined, the safety boundaries of different fuel rods under different operating conditions are accurately grasped, the performance analysis effect is enhanced, and PCI performance failure is prevented.

[0007] According to one aspect of the present application, a method for determining the PCI critical power of a fuel rod is provided, comprising: obtaining the expected power of a fuel rod in a nuclear reactor core at each operating stage during its life cycle; determining a target power and a target burnup of the fuel rod in a stable state according to the expected power; performing a transient change on the target power according to the restriction conditions corresponding to the cladding type of the fuel rod, and determining the PCI critical power of the fuel rod under the target power and target burnup operation.

[0008] Optionally, the target power is transiently changed according to the restriction corresponding to the cladding type of the fuel rod to determine the PCI critical power of the fuel rod under the target power and target burnup operation, including: determining a first power change amount and a second power change amount according to the magnitude of the target power; determining a first transient power according to the target power and the first power change amount; determining a second transient power according to the first transient power and the second power change amount; respectively determining a first index value and a second index value of an influencing factor of the fuel rod under the first transient power and the second transient power operation; wherein, if the first index value is less than the critical index value corresponding to the restriction, and the second index value is greater than the critical index value corresponding to the restriction, the first transient power corresponding to the first index value is used as the PCI critical power; if the first index value is greater than or equal to the critical index value corresponding to the restriction, or the second index value is less than or equal to the critical index value corresponding to the restriction, the first power change amount is adjusted so that the first index value re-determined according to the adjusted first transient power is less than the critical index value corresponding to the restriction, and the second index value is greater than the critical index value corresponding to the restriction.

[0009] Optionally, if the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, adjusting the first power change amount includes: if the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, reducing the first power change amount according to a preset power correction amount; if the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, increasing the first power change amount according to the preset power correction amount.

[0010] Optionally, the influencing factors include at least one of the following: cladding strain, fuel temperature, cladding strain energy density and cladding TRESCA stress.

[0011] Optionally, the fuel rod PCI critical power determination method further includes: performing an offset process on the expected power of at least one of the operation stages according to a preset offset.

[0012] Optionally, determining the target power and target burnup of the fuel rod in a stable state according to the expected power includes: interpolating or fitting the expected power collected at sampling moments to determine the target power at the calculation moment; wherein the calculation moment between the sampling moments is determined according to a preset time interval; and the target burnup at the calculation moment is determined according to the target power at the calculation moment.

[0013] Optionally, before the interpolation or fitting processing is performed on the expected power collected at the sampling moments, the method further includes: processing the expected power at any of the sampling moments according to the structural parameters of the fuel rod to update the expected power.

[0014] Optionally, the method for determining the PCI critical power of a fuel rod also includes: determining a PCI critical power database of the nuclear reactor core based on the PCI critical power; obtaining the actual power and actual fuel consumption of the fuel rod at the monitoring moment; calling a target PCI critical power in the PCI critical power database that matches the actual power and actual fuel consumption of the fuel rod; and generating an early warning message if the difference between the actual power of the fuel rod and the target PCI critical power does not meet a preset threshold condition.

[0015] According to another aspect of the present application, a fuel rod PCI critical power determination device is provided, comprising: an acquisition module for acquiring the expected power of a fuel rod in a nuclear reactor core at each operating stage during its life cycle; a determination module for determining a target power and a target burnup of the fuel rod in a stable state according to the expected power; and performing a transient change on the target power according to the restriction conditions corresponding to the cladding type of the fuel rod to determine the PCI critical power of the fuel rod under the target power and target burnup operation.

[0016] Optionally, the determination module is specifically used to: perform a transient change on the target power according to the restriction corresponding to the cladding type of the fuel rod, and determine the PCI critical power of the fuel rod under the target power and target burnup operation, including: determining a first power change amount and a second power change amount according to the magnitude of the target power; determining a first transient power according to the target power and the first power change amount; determining a second transient power according to the first transient power and the second power change amount; respectively determining a first index value and a second index value of an influencing factor of the fuel rod under the first transient power and the second transient power operation; wherein, if the first index value is less than the critical index value corresponding to the restriction, and the second index value is greater than the critical index value corresponding to the restriction, the first transient power corresponding to the first index value is used as the PCI critical power; if the first index value is greater than or equal to the critical index value corresponding to the restriction, or the second index value is less than or equal to the critical index value corresponding to the restriction, the first power change amount is adjusted so that the first index value re-determined according to the adjusted first transient power is less than the critical index value corresponding to the restriction, and the second index value is greater than the critical index value corresponding to the restriction.

[0017] Optionally, the determination module is specifically used to: if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the constraint condition, adjust the first power change amount, including: if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, reduce the first power change amount according to a preset power correction amount; if the second indicator value is less than or equal to the critical indicator value corresponding to the constraint condition, increase the first power change amount according to the preset power correction amount.

[0018] Optionally, the determination module is specifically used for: the influencing factors include at least one of the following: cladding strain, fuel temperature, cladding strain energy density and cladding TRESCA stress.

[0019] Optionally, the fuel rod PCI critical power determination device further includes:

[0020] The offset module is specifically used to: perform offset processing on the expected power of at least one of the operating stages according to a preset offset amount.

[0021] Optionally, the determination module is used to: interpolate or fit the expected power collected at the sampling moment to determine the target power at the calculation moment; wherein the calculation moment between the sampling moments is determined according to a preset time interval; and the target fuel consumption at the calculation moment is determined according to the target power at the calculation moment.

[0022] Optionally, the fuel rod PCI critical power determination device further includes:

[0023] The updating module is specifically used for: before interpolating or fitting the expected power collected at the sampling moment, it also includes processing the expected power at any of the sampling moments according to the structural parameters of the fuel rod to update the expected power.

[0024] Optionally, the fuel rod PCI critical power determination device further includes:

[0025] The early warning module is specifically used to: determine the PCI critical power database of the nuclear reactor core according to the PCI critical power; obtain the actual power and actual fuel consumption of the fuel rod at the monitoring time; call the target PCI critical power in the PCI critical power database that matches the actual power and actual fuel consumption of the fuel rod; if the difference between the actual power of the fuel rod and the target PCI critical power does not meet the preset threshold condition, generate early warning information.

[0026] According to another aspect of the present application, a computer device is provided, including a storage medium, a processor, and a computer program stored on the storage medium and executable on the processor, and the processor implements the steps of the above-mentioned fuel rod PCI critical power determination method when executing the program.

[0027] Through the above technical scheme, the present application provides a method, device and computer equipment for determining the PCI critical power of a fuel rod, which determines the target power and target burnup that may exist in the actual operation of the fuel rod according to the expected power of the fuel rod, fully considers the power fluctuation in the actual operation of the fuel rod, and determines the PCI critical power of the fuel rod when a transient state occurs under the target power and target burnup operation based on the restriction conditions corresponding to the cladding type of the fuel rod, accurately defines the safety limits of different fuel rods under different operating powers and burnups, improves the reliability and comprehensiveness of the PCI performance analysis of the fuel rod, and is conducive to adjusting and controlling the actual operation of the fuel rod, avoiding PCI performance failure of the fuel rod.

[0028] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0030] Figure 1 A schematic diagram of the process of determining the fuel rod PCI critical power provided by an embodiment of the present application is shown;

[0031] Figure 2 The structural block diagram of the fuel rod PCI critical power determination device provided in an embodiment of the present application is shown;

[0032] Figure 3 A schematic diagram of the design power history and virtual power history provided by an embodiment of the present application is shown. DETAILED DESCRIPTION

[0033] The present application will be described in detail below with reference to the accompanying drawings and in combination with embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other without conflict.

[0034] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be interpreted as limiting the present application.

[0035] Those skilled in the art will appreciate that, unless expressly stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that when we refer to an element as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, or there may be intermediate elements. In addition, the "connection" or "connection" used herein may include wireless connection or wireless fusion. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0036] Now, exemplary embodiments according to the present application will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in a variety of different forms and should not be interpreted as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present application thorough and complete, and to fully convey the concepts of these exemplary embodiments to those of ordinary skill in the art.

[0037] The fuel rod PCI critical power determination method provided in the embodiment of the present application can be applied to the terminal, can also be applied to the server, and can also be software running in the terminal or the server. In some embodiments, the terminal can be a smart phone, a tablet computer, a laptop computer, a desktop computer, etc.; the server side can be configured as an independent physical server, or a server cluster or distributed system composed of multiple physical servers, and can also be configured as a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communications, middleware services, domain name services, security services, CDN, and big data and artificial intelligence platforms; the software can be an application that implements the fuel rod PCI critical power determination method, etc., but is not limited to the above forms.

[0038] In this embodiment, a method for determining the PCI critical power of a fuel rod is provided. Figure 1 As shown, the method includes:

[0039] Step 101, obtaining the expected power of the fuel rods in the nuclear reactor core at each operation stage during the life cycle.

[0040] In this embodiment, the expected power of the fuel rods in the nuclear reactor core at each operating stage during the life cycle is obtained, which provides a reasonable reference basis and calculation basis for the subsequent determination of the PCI critical power, helps to understand the power demand and change trend of the fuel rods at different stages, and thus better evaluates its PCI performance under different operating conditions.

[0041] For example, Figure 3 As shown, considering the 1 / 8 symmetry of the nuclear reactor core, the design power history (expected power) of each fuel rod in any symmetrical 1 / 8 core of the nuclear reactor core during each cycle (operating stage) of the life cycle is obtained.

[0042] It should be noted that the design power history is the power change of the fuel rod at each time planned in the design stage. Usually, the life cycle of the fuel rod includes three cycles.

[0043] It can be understood that the design power history of any cycle of the fuel rod is the change in power of the fuel rod at each time in the cycle planned in the design stage. Since the operating power of the fuel rod in each cycle is basically stable, the design power history of each cycle of the fuel rod corresponds to an expected power, which is manifested as the design power history corresponding to each cycle is close to a straight line, and the design power history of each cycle may be the same or different.

[0044] It is worth mentioning that the determination of the design power history requires comprehensive consideration of multiple factors such as the overall performance requirements of the nuclear reactor, safety standards, material properties of the fuel rods, thermal hydraulic conditions, etc. Due to the different distribution of fuel in the core, the design power history corresponding to different fuel rods is also different.

[0045] Step 102, determining the target power and target burnup of the fuel rods in a stable state according to the expected power.

[0046] In this embodiment, the power fluctuation in the actual operation of the fuel rod is taken into account, and various powers and burn-ups that may occur in the actual operation of the fuel rod are predicted based on the expected power, thereby improving the comprehensiveness of the PCI performance analysis.

[0047] In one embodiment, the method for determining the fuel rod PCI critical power further includes: performing an offset process on the expected power of at least one operation stage according to a preset offset.

[0048] In this embodiment, the deviation of the power of the fuel rod in actual operation is reflected by presetting the offset, so that the expected power after the offset processing can accommodate the possible fluctuation of the power of the fuel rod in actual operation.

[0049] For example, Figure 3 As shown, taking the design power history of the cycle in the above embodiment as an example, the design power history (expected power) of at least one cycle (operation stage) is offset by a preset offset to reflect the power fluctuation of the fuel rod at different times, improve the comprehensiveness of the PCI performance analysis, and is manifested as a certain up and down change in the design power history of at least one cycle, and the design power history after the offset processing is used as the virtual power history (expected power after the offset processing). It can be understood that the virtual power history (expected power after the offset processing) of any cycle has an envelope of its design power (expected power) history.

[0050] For example, Figure 3 As shown, the three cycles of the fuel rod in the life cycle are the first cycle, the second cycle and the third cycle respectively. The design power history of the first cycle, the second cycle or the third cycle can be offset to obtain a virtual power history of one cycle. The design power history of the first cycle and the second cycle, or the first cycle and the third cycle, or the second cycle and the third cycle can also be offset to obtain a virtual power history of two cycles. The first cycle, the second cycle and the third cycle can also be offset to obtain a virtual power history of three cycles.

[0051] It should be noted that the preset offset can be set according to the design power history of the fuel rod and combined with the operating requirements, and can reflect the operating power range of the fuel rod in the actual application scenario. This application does not make specific restrictions. For example, the preset offset is ±10% or ±50% of the expected power.

[0052] It is worth mentioning that in actual application scenarios, if a nuclear reactor has a need to change the operating power range of the fuel rods, the preset offset can be changed according to the actual needs, so that the expected power after the offset processing can timely cover the power fluctuation corresponding to the actual situation, thereby improving the timeliness of this embodiment. For example, if the nuclear reactor relaxes the operating power range of the fuel rods, the preset offset is increased according to the relaxed range, thereby expanding the virtual power history of the fuel rods, and then in subsequent steps, the PCI critical power corresponding to a larger power range can be obtained.

[0053] Further, as a refinement and extension of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, step 102, that is, the step of determining the target power and target burnup of the fuel rod in a stable state according to the expected power, specifically includes: interpolating or fitting the expected power collected at the sampling time to determine the target power at the calculation time; wherein the calculation time between the sampling times is determined according to a preset time interval; and the target burnup at the calculation time is determined according to the target power at the calculation time.

[0054] In this embodiment, the expected power at the sampling moment is smoothed and optimized by interpolation or fitting, the power at the unsampled moment is filled, the amount of processed data is reduced, the fuel rod power trend and law are reflected, and the accuracy of the target power is improved.

[0055] Exemplarily, the sampling time is determined according to the preset sampling interval during the life cycle of the fuel rod, and the expected power collected at the sampling time is representative through the appropriate preset sampling interval, avoiding the processing of excessively large and complex continuous data, and reducing the burden of data calculation. Further, the expected power at the sampling time is interpolated or fitted to reflect the overall trend and law of the fuel rod power, and smooth and continuous power data is generated between the sampling times, so as to determine a more accurate power value at each time, effectively reduce the consumption of computing resources, improve the calculation accuracy of the subsequent critical PCI power, and optimize the calculation process.

[0056] It should be noted that, according to the data characteristics such as the distribution of the expected power collected and the overall trend, a suitable interpolation or fitting method can be selected to ensure the accuracy and effectiveness of the interpolation or fitting results, and this application does not impose any specific restrictions.

[0057] Furthermore, the calculation time between the sampling times is determined according to a preset time interval. After the expected power at the sampling time is interpolated or fitted, the power at all times is not output, but the target power at the calculation time is output to control the computing resources. The target power is used to accurately represent various steady-state powers that may exist in the fuel rod in actual operation, thereby improving the accuracy and comprehensiveness of the present application.

[0058] It should be noted that the preset sampling interval and the preset time interval are determined according to factors such as power fluctuations, computing resources and accuracy requirements in actual application scenarios, and this application does not impose any restrictions. For example, the preset sampling interval is 1000 hours or 2000 hours to achieve appropriate sampling, and the preset time interval can be 30 hours or 50 hours, etc., so that the target power obtained is more comprehensive and can be closer to the actual operation of the fuel rod.

[0059] For example, taking the design power history and virtual power history of the above cycle as an example, for the cycle in which the design power history (expected power) is offset, the virtual power history (expected power after offset) collected at the sampling time is interpolated or fitted to determine the target power at the calculation time. For the cycle in which the design power history (expected power) is not offset, the design power history (expected power) collected at the sampling time is interpolated or fitted to determine the target power at the calculation time.

[0060] Since the virtual power history reflects the fluctuations of the fuel rods in actual operation and can accommodate possible deviations in the power of the fuel rods in actual operation, the target power obtained according to the virtual power history or design power history of each cycle of the fuel rods can cover various steady-state powers that may exist in the actual operation of the fuel rods.

[0061] Since the operation state of the fuel rod usually needs to be determined based on the power and burnup at a certain moment, where the burnup is how much energy the fuel rod releases, and the burnup of the fuel rod is closely related to the power of the fuel rod, after determining the target power at the calculation moment, this embodiment further determines the target fuel at the calculation moment based on the target power, thereby determining multiple different operation points of the fuel rod through the target power and target burnup at the calculation moment.

[0062] It should be noted that the present embodiment does not specifically limit the method for determining the target fuel consumption. It is sufficient to obtain an accurate target fuel consumption. The present embodiment will not be elaborated in detail here.

[0063] Furthermore, as a refinement and extension of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, before interpolating or fitting the expected power collected at the sampling moment, the method also includes: processing the expected power at any sampling moment according to the structural parameters of the fuel rod to update the expected power.

[0064] In this embodiment, the expected power at any sampling moment is corrected and optimized in combination with the influence of the structural parameters of the fuel rod on the power generation, so as to obtain a more precise fuel rod power.

[0065] Exemplarily, the structural parameters of the fuel rods and the expected power at any sampling moment are input into the fuel performance analysis program, and the expected power at the sampling moment is updated according to the power output by the fuel performance analysis program.

[0066] It should be noted that the fuel performance analysis program can output more detailed power at a specified time based on the power changes of the input fuel rods at each time during the operation process and the structural parameters of the fuel rods. For example, the average power of the fuel rods is multiplied by its distribution in the axial section of the fuel rods to output the power of a certain axial section. The structural parameters of the fuel rods include neutron data (including neutron injection, power distribution along the axial section of the fuel rods, etc.), external parameters (including coolant pressure, temperature, thermal and hydraulic channel parameters, etc.), and internal structural parameters of the fuel rods (including length, inner and outer diameters, pre-filled gas pressure, etc.).

[0067] Step 103 , transiently changing the target power according to the restriction conditions corresponding to the cladding type of the fuel rod, and determining the PCI critical power of the fuel rod under the target power and target burnup operation.

[0068] Specifically, the expected power and the target power are both the power when the fuel rods are operating stably (steady-state power). However, during the actual operation of the fuel rods, different transient processes will occur, resulting in transient mutations in the steady-state power of the fuel rods, thereby changing the PCI performance of the fuel rods, which is prone to PCI performance failure and affects the normal operation of the nuclear reactor.

[0069] In this embodiment, in order to prevent cladding failure, the impact of transient processes on fuel rods is taken into account, and based on the restriction conditions corresponding to the cladding type of the fuel rod, the maximum transient change that can occur in the fuel rod under the operation of the target power and target burnup is determined, thereby determining the PCI critical power. The PCI critical power is used to accurately define the safety limits of the fuel rod under different steady-state powers and burnups, thereby improving the reliability and comprehensiveness of the PCI performance analysis of the fuel rod, which is conducive to adjusting and controlling the actual operation of the fuel rod.

[0070] Further, as a refinement and expansion of the specific implementation of the above embodiment, in order to fully illustrate the specific implementation process of this embodiment, step 103, that is, the step of performing a transient change on the target power according to the restriction conditions corresponding to the cladding type of the fuel rod to determine the PCI critical power of the fuel rod under the target power and target burnup operation, specifically includes: determining a first power change amount and a second power change amount according to the magnitude of the target power; determining a first transient power according to the target power and the first power change amount; determining a second transient power according to the first transient power and the second power change amount; respectively determining the fuel rod at the first transient power and the second transient power. The first indicator value and the second indicator value of the influencing factor under the state power operation; wherein, if the first indicator value is less than the critical indicator value corresponding to the constraint condition, and the second indicator value is greater than the critical indicator value corresponding to the constraint condition, the first transient power corresponding to the first indicator value is used as the PCI critical power; if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the constraint condition, the first power change amount is adjusted so that the first indicator value re-determined according to the adjusted first transient power is less than the critical indicator value corresponding to the constraint condition, and the second indicator value is greater than the critical indicator value corresponding to the constraint condition.

[0071] In this embodiment, based on the restriction conditions corresponding to the cladding type, the maximum power that the target power can reach is gradually approached in a cyclic manner, and the PCI critical power corresponding to the target power is finally determined, thereby improving the calculation efficiency and ensuring the accuracy of the PCI critical power.

[0072] Further, as a refinement and expansion of the specific implementation methods of the above-mentioned embodiments, in order to fully illustrate the specific implementation process of this embodiment, if the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, the step of adjusting the first power change amount specifically includes: if the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, reducing the first power change amount according to a preset power correction amount; if the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, increasing the first power change amount according to the preset power correction amount.

[0073] In this embodiment, the first power change amount is adjusted by a preset power correction amount to control the change amplitude of the first transient power, so that the change of the first transient power has a certain regularity and controllability, thereby ensuring the rationality of the adjustment of the first transient power, reducing unnecessary power tests, and saving computing resources and time.

[0074] Specifically, the first power change △P1 and the second power change △P2 are determined according to the magnitude of the target power P. The first power change △P1 and the second power change △P2 provide a reference for reasonable power change, avoiding inaccurate calculation or low efficiency caused by excessive or small power change. Further, the target power P in steady state is transiently changed by the first power change △P1, so that the target power P reaches different transient powers, and the accuracy of the PCI critical power is guaranteed by the second power change △P2. For example, the operating power of the fuel rod is usually in the range of 10-50kw / m. If the target power P of the fuel rod is 30kw / m and the target fuel consumption is BMWd / tU at a certain calculation moment, the first power change △P1 is determined to be a value such as 10kw / m according to the magnitude of the target power P; according to the requirements for the accuracy of the PCI critical power in the actual application scenario, the second power change △P2 can be determined to be a value such as 1kW / m or 0.1kW / m.

[0075] Exemplarily, in order to achieve the process of stepwise approximation, the first transient power is first determined according to the target power P and the first power variation △P1, and the first index value of the influencing factor of the fuel rod under the first transient power is determined to provide basic data for subsequent adjustment and optimization. Among them, the first index value of the influencing factor is used to evaluate the PCI performance of the fuel rod under the first transient power. The influencing factors include at least one of the following: cladding strain, fuel temperature, cladding strain energy density and cladding TRESCA stress.

[0076] It should be noted that the PCI performance of the fuel rod under different transient powers can be calculated by the fuel performance analysis program. The fuel performance analysis program can output the fuel rod burnup, fuel temperature, cladding stress and strain, fuel rod internal pressure, cladding corrosion and other performance characterization parameters at a specified time through the corresponding analysis model based on the power change of the fuel rod at each time during the operation process and the structural parameters of the fuel rod mentioned above.

[0077] It is worth mentioning that when evaluating PCI performance, one or more evaluation criteria need to be determined according to different grades of fuel rod cladding materials (cladding types). For example, the evaluation criteria include fuel temperature criteria, cladding strain criteria, cladding strain energy density criteria, and cladding TRESCA stress criteria. Among them, the fuel temperature criterion avoids excessive melting of fuel pellets and prevents the melted fuel pellets from bringing greater stress to the cladding; the cladding strain criterion avoids damage failure due to excessive cladding strain under transient conditions; the cladding strain energy density criterion avoids damage failure due to excessive cladding strain energy density under transient conditions; the cladding TRESCA stress criterion avoids damage failure due to excessive TRESCA stress under transient conditions.

[0078] Exemplarily, the evaluation criteria that the fuel rod cladding type meets are used as the restriction conditions corresponding to the fuel rod cladding type, and the critical index values ​​corresponding to the restriction conditions are determined according to the evaluation criteria that the fuel rod cladding type meets. For example, the critical index value corresponding to the fuel temperature criterion is that the fuel temperature does not exceed 2590°C, the critical index value corresponding to the cladding strain criterion is that the transient cladding strain change (i.e., the cladding strain after the transient minus the cladding strain before the transient) is less than 1%, the critical index value corresponding to the cladding strain energy density criterion is that the cladding strain energy density does not exceed 2.87MPa, and the critical index value corresponding to the cladding TRESCA stress criterion is that the cladding TRESCA stress does not exceed 535MPa.

[0079] It should be noted that if the fuel rod cladding type meets multiple evaluation criteria, the evaluation criterion with the greatest restriction on the fuel rods among the evaluation criteria will be used as the restriction condition to obtain the lowest PCI critical power among the PCI critical powers corresponding to the multiple evaluation criteria to ensure the safe operation of the fuel rods.

[0080] For example, if the cladding strain criterion is used as a constraint condition, the first index value of the influencing factor of the fuel rod at the first transient power is the first cladding strain variation.

[0081] Furthermore, in order to determine the maximum transient power corresponding to the fuel rod when the fuel rod is operating at the target power P and the target burnup B and meets the restriction conditions, it is necessary to continuously adjust the first power change △P1 to change the first transient power, so that the first indicator value determined according to the first transient power gradually approaches the critical indicator value until the PCI critical power is determined.

[0082] Specifically, if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, it means that the first transient power has exceeded the maximum transient power allowed by the constraint condition. Then, it is necessary to appropriately adjust the first power change △P1 so that the first transient power gradually approaches the maximum transient power allowed by the constraint condition on the basis of meeting the constraint condition.

[0083] Exemplarily, if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, the first power variation ΔP1 is adjusted, and the magnitude relationship between the first indicator value re-determined according to the adjusted first transient power and the critical indicator value corresponding to the constraint condition is determined.

[0084] The first power variation ΔP1 is gradually corrected according to the preset power correction amount, so as to efficiently find the transient power close to the critical value.

[0085] It should be noted that the change in power means the change in energy in a short period of time, so the index value of the influencing factor will also change accordingly with the change in power. For example, a substantial increase in transient power means the rapid release of energy in a short period of time. This rapid energy change will have a stronger impact and influence on the cladding, resulting in an increase in the index value.

[0086] Exemplarily, if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, the first power change amount △P1 is reduced according to the preset power correction amount so that the first transient power is appropriately reduced, and the relationship between the first indicator value re-determined based on the reduced first transient power and the critical indicator value corresponding to the constraint condition is determined.

[0087] It is worth mentioning that the preset power correction amount can be determined according to the difference between the first index value and the critical index value corresponding to the constraint condition, so as to achieve appropriate adjustment of the first transient power and avoid excessive or small power changes leading to excessive calculation times. For example, if the first index value is close to the critical index value corresponding to the constraint condition, the preset power correction amount can be determined as a value such as 1kW / m or 0.1kW / m, so as to gradually narrow the gap between the first transient power and the maximum transient power allowed by the constraint condition. If the difference between the first index value and the critical index value corresponding to the constraint condition is large, the preset power correction amount can be determined as a value such as 5kW / m or 8kW / m according to the first power change △P1, so that the first transient power quickly approaches the maximum transient power allowed by the constraint condition.

[0088] Furthermore, if the first indicator value is less than the critical indicator value corresponding to the restriction condition, it indicates that the first transient power meets the restriction condition, but it is necessary to further determine whether the first transient power is very close to the maximum transient power allowed by the restriction condition.

[0089] Exemplarily, if the first indicator value is less than the critical indicator value corresponding to the constraint condition, the second transient power is determined according to the first transient power and the second power change ΔP2, and the second indicator value of the influencing factor of the fuel rod under the second transient power is determined. The second indicator value of the influencing factor is used to evaluate the PCI performance of the fuel rod under the second transient power.

[0090] It is understandable that the second index value is based on the same principle as the first index value. For example, if the cladding strain criterion is used as a limiting condition, the second index value of the influencing factor of the fuel rod at the second transient power is the second cladding strain variation.

[0091] Specifically, if the second indicator value is less than the critical indicator value corresponding to the restriction condition, it means that although the increased first transient power meets the restriction condition, there is still a certain gap between the first transient power and the maximum transient power allowed by the restriction condition, and the accuracy corresponding to the second power change △P2 is not reached. In this case, it is necessary to further adjust the first power change △P1 to make the first transient power closer to the maximum transient power allowed by the restriction condition.

[0092] Exemplarily, similar to the above-mentioned reduction of the first power change △P1, if the second index value is less than the critical index value corresponding to the constraint condition, the first power change △P1 is increased according to the preset power correction amount to increase the first transient power, and the relationship between the first index value re-determined according to the increased first transient power and the critical index value corresponding to the constraint condition is determined.

[0093] If the second index value is greater than the critical index value corresponding to the constraint condition, it means that if the power is increased slightly on the basis of the first transient power, it will exceed the limit of the constraint condition. It is determined that the first transient power is very close to the maximum transient power allowed by the constraint condition and meets the accuracy corresponding to the second power change △P2. Therefore, the PCI critical power of the fuel rod under the target power P and target burnup B is determined based on the first transient power at this time.

[0094] Exemplarily, if the first indicator value is smaller than the critical indicator value corresponding to the constraint condition, and the second indicator value is larger than the critical indicator value corresponding to the constraint condition, the first transient power corresponding to the first indicator value is used as the PCI critical power.

[0095] It is understandable that if the first indicator value and the second indicator value do not simultaneously satisfy that the first indicator value is less than the critical indicator value corresponding to the constraint condition, and the second indicator value is greater than the critical indicator value corresponding to the constraint condition, the above cycle needs to be repeated until the PCI critical power is determined according to the target power P.

[0096] It is worth mentioning that if multiple target powers P are relatively close, then the PCI critical power corresponding to one of the multiple target powers P that are relatively close can be calculated, and the PCI critical power corresponding to one of the target powers P can be used to represent the PCI critical power corresponding to multiple target powers P that are relatively close, so as to save computing resources. Similarly, if the target powers P corresponding to multiple fuel rods are relatively overlapped with the target burnup B, then the PCI critical power corresponding to one of the multiple fuel rods that are relatively overlapped can be calculated.

[0097] In one embodiment, the method for determining the PCI critical power of a fuel rod also includes: determining a PCI critical power database of a nuclear reactor core based on the PCI critical power; obtaining the actual power and actual fuel consumption of the fuel rod at the monitoring time; calling a target PCI critical power in the PCI critical power database that matches the actual power and actual fuel consumption of the fuel rod; and generating an early warning message if the difference between the actual power of the fuel rod and the target PCI critical power does not meet a preset threshold condition.

[0098] In this embodiment, a PCI critical power database of the nuclear reactor core is established according to the PCI critical power. The PCI critical power database is used to monitor the actual power and actual burnup of each fuel rod online to ensure the normal operation of the nuclear reactor.

[0099] Specifically, according to the PCI critical power of each fuel rod under the target power P and the target fuel, a PCI critical power database of each fuel rod in the whole core is established and fed back to the nuclear reactor online monitoring system for use. The online monitoring system monitors the actual power and actual burnup of each fuel rod in the nuclear reactor in real time, and calls the target PCI critical power corresponding to the actual power of the fuel rod when the PCI performance reaches the limit by interpolating, searching, mapping, etc. the PCI critical power database, and adjusts and controls the core according to the target PCI critical power to avoid PCI performance failure of the fuel rod.

[0100] Exemplarily, if the difference between the actual power of the fuel rod and the target PCI critical power does not meet the preset threshold condition, an early warning message is generated to achieve effective monitoring of each fuel rod of the nuclear reactor and ensure the normal operation of the nuclear reactor.

[0101] Among them, the preset threshold conditions can be specifically set according to factors such as the safety design standards of the nuclear reactor or the performance characteristics of the fuel rods to ensure that the fuel rods can operate safely within a reasonable power deviation range. This application does not make specific restrictions.

[0102] It is worth mentioning that according to the margin between the actual power of the fuel rods and the target PCI critical power, some low-power fuel rods can be controlled to appropriately increase the power operation, thereby improving the economy of the nuclear power plant and the utilization rate of nuclear fuel.

[0103] It should be noted that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0104] Furthermore, if Figure 2As shown, as a specific implementation of the above-mentioned fuel rod PCI critical power determination method, an embodiment of the present application provides a fuel rod PCI critical power determination device 200, and the fuel rod PCI critical power determination device 200 includes: an acquisition module 201 and a determination module 202.

[0105] The acquisition module 201 is used to acquire the expected power of the fuel rods in the nuclear reactor core at each operation stage during the life cycle.

[0106] A determination module 202, configured to determine a target power and a target burnup of the fuel rod in a stable state according to the expected power;

[0107] And, the target power is transiently changed according to the restriction conditions corresponding to the cladding type of the fuel rod, and the PCI critical power of the fuel rod under the target power and target burnup operation is determined.

[0108] In one embodiment, the determination module 202 is specifically used to: perform a transient change on the target power according to the constraint corresponding to the cladding type of the fuel rod, and determine the PCI critical power of the fuel rod under the target power and target burnup operation, including: determining a first power change amount and a second power change amount according to the magnitude of the target power; determining a first transient power according to the target power and the first power change amount; determining a second transient power according to the first transient power and the second power change amount; respectively determining a first index value and a second index value of an influencing factor of the fuel rod under the first transient power and the second transient power operation; wherein, if the first index value is less than the critical index value corresponding to the constraint, and the second index value is greater than the critical index value corresponding to the constraint, the first transient power corresponding to the first index value is used as the PCI critical power; if the first index value is greater than or equal to the critical index value corresponding to the constraint, or the second index value is less than or equal to the critical index value corresponding to the constraint, the first power change amount is adjusted so that the first index value re-determined according to the adjusted first transient power is less than the critical index value corresponding to the constraint, and the second index value is greater than the critical index value corresponding to the constraint.

[0109] In one embodiment, the determination module 202 is specifically used to: if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the constraint condition, adjust the first power change amount, including: if the first indicator value is greater than or equal to the critical indicator value corresponding to the constraint condition, reduce the first power change amount according to a preset power correction amount; if the second indicator value is less than or equal to the critical indicator value corresponding to the constraint condition, increase the first power change amount according to the preset power correction amount.

[0110] In one embodiment, the determination module 202 is specifically configured to: the influencing factors include at least one of the following: cladding strain, fuel temperature, cladding strain energy density, and cladding TRESCA stress.

[0111] In one embodiment, the fuel rod PCI critical power determination device further includes:

[0112] The offset module is specifically used to perform offset processing on the expected power of at least one operation stage according to a preset offset amount.

[0113] In one embodiment, the determination module 202 is used to: interpolate or fit the expected power collected at the sampling moment to determine the target power at the calculation moment; wherein the calculation moment between the sampling moments is determined according to a preset time interval; and the target fuel consumption at the calculation moment is determined according to the target power at the calculation moment.

[0114] In one embodiment, the fuel rod PCI critical power determination device further includes:

[0115] The updating module is specifically used for: before interpolating or fitting the expected power collected at the sampling moment, it also includes processing the expected power at any sampling moment according to the structural parameters of the fuel rod to update the expected power.

[0116] In one embodiment, the fuel rod PCI critical power determination device further includes:

[0117] The early warning module is specifically used to: determine the PCI critical power database of the nuclear reactor core according to the PCI critical power; obtain the actual power and actual fuel consumption of the fuel rods at the monitoring time; call the target PCI critical power in the PCI critical power database that matches the actual power and actual fuel consumption of the fuel rods; if the difference between the actual power of the fuel rods and the target PCI critical power does not meet the preset threshold condition, generate an early warning message.

[0118] The specific definition of the fuel rod PCI critical power determination device can refer to the definition of the fuel rod PCI critical power determination method mentioned above, which will not be repeated here. Each module in the above fuel rod PCI critical power determination device can be implemented in whole or in part by software, hardware and their combination. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0119] Based on this understanding, the technical solution of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, USB flash drive, mobile hard disk, etc.), including a number of instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute the methods of various implementation scenarios of the present application.

[0120] In order to achieve the above-mentioned purpose, the embodiment of the present application further provides a computer device, which can be a personal computer, a server, a network device, etc., and the computer device includes a storage medium and a processor; the storage medium is used to store a computer program; the processor is used to execute the computer program to achieve the above-mentioned Figure 1 The method for determining the fuel rod PCI critical power is shown.

[0121] In one embodiment, the computer device may further include a user interface, a network interface, a camera, a radio frequency (RF) circuit, a sensor, an audio circuit, a WI-FI module, etc. The user interface may include a display, an input unit such as a keyboard, etc., and the optional user interface may also include a USB interface, a card reader interface, etc. The network interface may optionally include a standard wired interface, a wireless interface (such as a Bluetooth interface, a WI-FI interface), etc.

[0122] Those skilled in the art will appreciate that the computer device structure provided in this embodiment does not limit the computer device, and may include more or fewer components, or a combination of certain components, or different component arrangements.

[0123] The storage medium may also include an operating system and a network communication module. The operating system is a program that manages and saves the hardware and software resources of the computer device, and supports the operation of information processing programs and other software and / or programs. The network communication module is used to realize communication between the components inside the storage medium, and communication with other hardware and software in the physical device.

[0124] Through the description of the above implementation methods, those skilled in the art can clearly understand that the present application can be implemented by means of software plus a necessary general hardware platform, or the embodiments of the present application can be implemented by hardware.

[0125] Those skilled in the art will appreciate that the accompanying drawings are only schematic diagrams of a preferred implementation scenario, and the modules or processes in the accompanying drawings are not necessarily necessary for implementing the present application. Those skilled in the art will appreciate that the modules in the devices in the implementation scenario can be distributed in the devices of the implementation scenario according to the description of the implementation scenario, or can be changed accordingly and located in one or more devices different from the present implementation scenario. The modules of the above-mentioned implementation scenario can be combined into one module, or can be further split into multiple submodules.

[0126] The above serial numbers of this application are only for description and do not represent the advantages and disadvantages of the implementation scenarios. The above disclosure is only a few specific implementation scenarios of this application, but this application is not limited to them, and any changes that can be thought of by technicians in this field should fall within the scope of protection of this application.

Claims

1. A method for determining fuel rod PCI critical power, characterized in that: The method comprises: Obtain the expected power of the fuel rods in the nuclear reactor core at each operating stage during its life cycle; Determining a target power and a target burnup of the fuel rod in a stable state according to the expected power; The target power is transiently changed according to the restriction conditions corresponding to the cladding type of the fuel rod, and the PCI critical power of the fuel rod under the target power and target burnup operation is determined.

2. The method for determining the fuel rod PCI critical power according to claim 1, characterized in that: The step of transiently changing the target power according to the restriction condition corresponding to the cladding type of the fuel rod to determine the PCI critical power of the fuel rod under the target power and target burnup operation includes: Determining a first power change amount and a second power change amount according to the magnitude of the target power; determining a first transient power according to the target power and the first power variation; determining a second transient power according to the first transient power and the second power variation; Determine the first index value and the second index value of the influencing factors of the fuel rod under the first transient power and the second transient power operation respectively; wherein, If the first indicator value is less than the critical indicator value corresponding to the restriction condition, and the second indicator value is greater than the critical indicator value corresponding to the restriction condition, taking the first transient power corresponding to the first indicator value as the PCI critical power; If the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, adjust the first power change so that the first indicator value re-determined based on the adjusted first transient power is less than the critical indicator value corresponding to the restriction condition, and the second indicator value is greater than the critical indicator value corresponding to the restriction condition.

3. The method for determining the fuel rod PCI critical power according to claim 2, characterized in that: If the first indicator value is greater than or equal to the critical indicator value corresponding to the restriction condition, or the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, adjusting the first power change amount includes: If the first indicator value is greater than or equal to the critical indicator value corresponding to the limiting condition, reducing the first power change amount according to a preset power correction amount; If the second indicator value is less than or equal to the critical indicator value corresponding to the restriction condition, the first power change amount is increased according to the preset power correction amount.

4. The method for determining the fuel rod PCI critical power according to claim 2, characterized in that: The influencing factors include at least one of the following: cladding strain, fuel temperature, cladding strain energy density and cladding TRESCA stress.

5. The method for determining fuel rod PCI critical power according to claim 1, characterized in that: The method further comprises: The expected power of at least one of the operating stages is offset according to a preset offset.

6. The method for determining fuel rod PCI critical power according to claim 1, characterized in that: The step of determining the target power and target burnup of the fuel rod in a stable state according to the expected power includes: Performing interpolation or fitting processing on the expected power collected at the sampling moment to determine the target power at the calculation moment; wherein the calculation moment between the sampling moments is determined according to a preset time interval; The target fuel consumption at the calculation time is determined based on the target power at the calculation time.

7. The method for determining fuel rod PCI critical power according to claim 6, characterized in that: Before performing interpolation or fitting processing on the expected power collected at the sampling time, the method further includes: The expected power at any sampling moment is processed according to the structural parameters of the fuel rod to update the expected power.

8. The method for determining fuel rod PCI critical power according to claim 1, characterized in that: The method further comprises: Determining a PCI critical power database of the nuclear reactor core according to the PCI critical power; Obtaining the actual power and actual burnup of the fuel rod at the monitoring time; Calling the target PCI critical power in the PCI critical power database that matches the actual power and actual burnup of the fuel rod; If the difference between the actual power of the fuel rod and the target PCI critical power does not meet the preset threshold condition, an early warning message is generated.

9. A fuel rod PCI critical power determination device, characterized in that: The device comprises: An acquisition module, used to acquire the expected power of the fuel rods in the nuclear reactor core at various operation stages during the life cycle; a determination module, configured to determine a target power and a target burnup of the fuel rod in a stable state according to the expected power; and The target power is transiently changed according to the restriction conditions corresponding to the cladding type of the fuel rod, and the PCI critical power of the fuel rod under the target power and target burnup operation is determined.

10. A computer device comprising a storage medium, a processor, and a computer program stored in the storage medium and executable on the processor, characterized in that: When the processor executes the program, the method for determining the fuel rod PCI critical power according to any one of claims 1 to 8 is implemented.

Images