Reuse method and system of fuel element based on pebble-bed high-temperature gas cooled reactor

Abstract

The invention provides a reuse method and system for a fuel element based on a pebble-bed high-temperature gas cooled reactor, and the method comprises the steps: firstly constructing a reactor core model containing a to-be-reused fuel element and a refueling scheme based on the data of the to-be-reused fuel element and the main design parameters of the pebble-bed high-temperature gas cooled reactor, then building an initial loading reactor after multi-working-condition safety verification, and carrying out the multi-working-condition safety verification; and continuously recycling the to-be-reused fuel which does not reach the designed burnup in the operation of the reactor core until the to-be-reused fuel reaches the standard and is discharged, so that the safe and efficient reuse of the to-be-reused fuel element in the pebble-bed high-temperature gas cooled reactor is realized. According to the method, the nuclear fuel utilization rate is increased, the operation cost is reduced, the radioactive waste treatment pressure is reduced, meanwhile, the reactor operation stability and safety are guaranteed, and the method has important significance in promoting the economic and sustainable development of nuclear energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high temperature gas cooled reactor application, and in particular to a fuel element reuse method and system based on a pebble bed high temperature gas cooled reactor. BACKGROUND

[0002] As an important branch of advanced nuclear energy technology, the high temperature gas cooled reactor takes the spherical coated particle fuel element as the core fuel form, adopts graphite as the moderator and helium as the coolant, and one of its core advantages is the fuel management mode of "non-stop refueling", that is, the refueling operation can be completed during the continuous operation of the reactor, without interrupting the operation, which significantly improves the operation efficiency. Among them, the pebble bed high temperature gas cooled reactor has become one of the mainstream technical routes of high temperature gas cooled reactors due to its compact core structure and flexible fuel cycle.

[0003] The core establishment of the pebble bed high temperature gas cooled reactor needs to go through the transition process from the "initial core" to the "equilibrium core". However, during this process, the discharged burnup of low enrichment fuel elements shows a trend of gradually increasing. This means that most of the low enrichment fuel elements are discharged from the core in the "low burnup" state without reaching the designed burnup, and there is still a large amount of available nuclear fuel inside that has not been fully consumed. This situation of discharging before reaching the designed burnup directly leads to a decrease in nuclear fuel utilization rate, causing significant economic waste, and also increasing the total amount of spent fuel and subsequent processing pressure.

[0004] Therefore, how to realize the efficient reuse of such fuel elements that have not reached the designed burnup through technical means has become a key problem to improve the economic efficiency and nuclear fuel utilization rate of the pebble bed high temperature gas cooled reactor. SUMMARY

[0005] The present application aims to at least partially solve one of the technical problems in the related art.

[0006] To achieve the above purpose, the first aspect of the present application proposes a fuel element reuse method based on a pebble bed high temperature gas cooled reactor, comprising:

[0007] Based on the number and burnup data of the fuel elements to be reused and the main design parameters of the pebble bed high temperature gas cooled reactor, a core model and a core loading and refueling scheme of the pebble bed high temperature gas cooled reactor containing the fuel elements to be reused are established;

[0008] Based on the core model and the core loading and refueling scheme, the core key parameters under multiple working conditions are calculated, it is judged whether the core key parameters belong to the safety range, and in the case that the core key parameters belong to the safety range, the fuel elements to be reused are loaded into the core according to the selected core loading and refueling scheme to form an initial core;

[0009] The core is driven to operate, and the burnup of the fuel elements to be reused in the initial core is obtained by detection, and the fuel elements to be reused which do not reach the design burnup are continuously loaded into the core and participate in the in-core cycle according to the core reloading scheme until the fuel elements to be reused are unloaded after reaching the design burnup.

[0010] Optionally, the step of loading the fuel elements to be reused into the core according to the core reloading scheme further comprises:

[0011] The graphite balls and low-enrichment fuel elements are loaded into the core and mixed with the fuel elements to be reused at a preset ratio to form mixed fuel elements.

[0012] Optionally, the reloading scheme at least includes the reloading speed, frequency and mixing ratio of the mixed fuel elements.

[0013] Optionally, before the step of continuously loading the fuel elements to be reused which do not reach the design burnup into the core and participating in the in-core cycle according to the core reloading scheme, the method further comprises:

[0014] The graphite balls in the mixed fuel elements are unloaded in batches by using a fuel loading and unloading system to form a fuel vacancy in the core; the fuel elements to be reused which do not reach the design burnup are continuously loaded into the fuel vacancy and participate in the in-core cycle according to the core reloading scheme.

[0015] Optionally, the method further comprises:

[0016] In the case that the core key parameters are not in the safety range, the core model and the core reloading scheme are re-established.

[0017] Optionally, the method of establishing a core model and a core reloading scheme of a pebble bed high-temperature gas-cooled reactor containing the fuel elements to be reused further comprises:

[0018] The core model and the core reloading scheme of the pebble bed high-temperature gas-cooled reactor are established by using a pebble bed high-temperature gas-cooled reactor nuclear design software.

[0019] Optionally, the main design parameters include core power, core diameter and height, fuel element enrichment, coolant inlet and outlet temperature and flow.

[0020] Optionally, the multiple working conditions include full-power working condition, low-power working condition and subcritical working condition, and the core key parameters include core power distribution, temperature distribution and gas pressure.

[0021] Optionally, the fuel elements to be reused are composed of low-enrichment fuel elements with a target burnup of no less than 57 GWd / tU unloaded in the transition process from the initial loading core to the stable operation core of the pebble bed high-temperature gas-cooled reactor.

[0022] To achieve the above object, the second aspect of the present application provides a fuel element reuse system based on a pebble bed high-temperature gas-cooled reactor, comprising:

[0023] a model establishing module, configured to establish a core model of the pebble bed high-temperature gas-cooled reactor containing the fuel elements to be reused and a core loading and reloading scheme based on the number and burnup data of the fuel elements to be reused and the main design parameters of the pebble bed high-temperature gas-cooled reactor;

[0024] a simulation calculation module, configured to calculate core key parameters under multiple working conditions based on the core model and the core loading and reloading scheme, and to determine whether the core key parameters belong to a safe range;

[0025] a first control module, configured to load the fuel elements to be reused into the core to form an initial loading core according to the core loading and reloading scheme in the case that the core key parameters belong to the safe range;

[0026] a second control module, configured to drive the core to operate, and to continue loading the fuel elements to be reused which have not reached the design burnup into the core and participate in the in-core cycle based on the burnup of the fuel elements to be reused loaded into the core and the core loading and reloading scheme, until the fuel elements to be reused are unloaded after reaching the design burnup.

[0027] The fuel element reuse method and system based on a pebble bed high-temperature gas-cooled reactor provided by the present application at least have the following beneficial effects:

[0028] The fuel element reuse method and system based on a pebble bed high-temperature gas-cooled reactor provided by the present application comprises constructing a core model containing the fuel elements to be reused and a loading and reloading scheme based on the data of the fuel elements to be reused and the main design parameters of the pebble bed high-temperature gas-cooled reactor, then forming an initial loading core after safety verification under multiple working conditions, and then continuously recycling the fuel elements to be reused which have not reached the design burnup in the core operation until they are unloaded after reaching the standard, thereby realizing safe and efficient reuse of the fuel elements to be reused in the pebble bed high-temperature gas-cooled reactor. The method not only improves the nuclear fuel utilization rate and reduces the operation cost, but also reduces the pressure of radioactive waste treatment, while ensuring the stability and safety of the reactor operation, which is of great significance to the economic and sustainable development of nuclear energy.

[0029] Additional aspects and advantages of the present application will be made apparent by the following description. BRIEF DESCRIPTION OF DRAWINGS

[0030] The above and / or additional aspects and advantages of the present application will become apparent and be readily appreciated from the following description, including the references to the figures, in which:

[0031] Figure 1 A flowchart of a method for recycling fuel elements of a pebble bed high temperature gas cooled reactor according to an embodiment of the present application is shown.

[0032] Figure 2 A diagram showing the change in burnup of low enrichment fuel elements discharged from a pebble bed high temperature gas cooled reactor according to an embodiment of the present application is shown.

[0033] Figure 3 A block diagram of a recycling system for fuel elements of a pebble bed high temperature gas cooled reactor according to an embodiment of the present application is shown.

[0034] Figure 4 A block diagram of an electronic device according to an embodiment of the present application is shown. DETAILED DESCRIPTION

[0035] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals are used throughout the figures to refer to the same or like components. The embodiments described below are illustrative of the present application and are not intended to be limiting thereof.

[0036] A pebble bed high temperature gas cooled reactor is a reactor that uses spherical coated particle fuel elements, graphite as a moderator, and helium as a coolant. A significant feature of the pebble bed high temperature gas cooled reactor is that it does not stop the reactor to change the fuel. The initial core of the pebble bed high temperature gas cooled reactor is composed of a mixture of low enrichment fuel elements and graphite spheres. Since the core fission products are limited at this time, only a small amount of fissile material is needed to achieve criticality.

[0037] After the initial core is established, the reactor needs to go through a transition process to reach the equilibrium core. First, the reactor is operated at a certain power, and the graphite spheres are discharged in batches, while an equal amount of low enrichment fuel elements are loaded, until the core is composed entirely of low enrichment fuel elements. Subsequently, the core begins to discharge low enrichment spent fuel elements, while high enrichment fuel elements are loaded, until the core is composed entirely of high enrichment fuel elements, reaching the equilibrium core state. During this process, the burnup of low enrichment spent fuel elements gradually increases, but most of them are discharged from the core before reaching the design burnup, resulting in economic waste.

[0038] Based on the above problems, the application provides a method and system for recycling fuel elements based on a pebble bed high temperature gas cooled reactor. The data of the fuel elements to be recycled and the main design parameters of the pebble bed high temperature gas cooled reactor are used to construct a core model and a refueling scheme of the core containing the fuel elements to be recycled. After safety verification under multiple working conditions, an initial loading reactor is established. Then, the fuel elements to be recycled that do not reach the design burnup are continuously recycled in the core until they are discharged, thereby realizing safe and efficient recycling of the fuel elements to be recycled in the pebble bed high temperature gas cooled reactor.

[0039] According to a first aspect of the application, a method for recycling fuel elements based on a pebble bed high temperature gas cooled reactor is provided. Please refer to Figure 1 , Figure 1 is a flowchart of the method for recycling fuel elements based on a pebble bed high temperature gas cooled reactor provided by the application. As shown in Figure 1 , the method comprises the following steps:

[0040] S1, based on the number and burnup data of the fuel elements to be recycled and the main design parameters of the pebble bed high temperature gas cooled reactor, a core model and a core refueling scheme of the pebble bed high temperature gas cooled reactor containing the fuel elements to be recycled are established.

[0041] It can be understood that the number and burnup data of the fuel elements to be recycled and the main design parameters of the reactor can provide basic data for the core model.

[0042] In some embodiments, the core model is a digital and abstract simulation representation of the core of the pebble bed high temperature gas cooled reactor. It is constructed according to the main design parameters of the pebble bed high temperature gas cooled reactor, which include the core power, the core diameter and height, the fuel element enrichment, the coolant inlet and outlet temperature and flow rate, etc. At the same time, the core model also considers the number and burnup data of the fuel elements to be recycled. Through these information inputs, the core model can accurately reflect the geometric structure, nuclear physical characteristics and thermal hydraulic characteristics of the core, etc.

[0043] As an example, the core power determines the output capacity of the pebble bed high temperature gas cooled reactor. According to the core diameter and the core height, the spatial size of the core can be determined to provide a spatial framework for the distribution of fuel elements and coolant. According to the fuel element enrichment and the burnup data of the fuel elements to be recycled, the generation, transport and absorption process of neutrons in the core, as well as the fission reaction and burnup change of the fuel can be simulated. That is, these main design parameters of the pebble bed high temperature gas cooled reactor jointly define the framework for subsequent core model establishment and refueling scheme development.

[0044] In some embodiments, the refueling scheme is a specific and operable rule developed based on the simulation results of the core model and combined with actual operation requirements, so as to realize safe and efficient recycling of the fuel elements to be recycled.

[0045] As an example, the core reloading scheme specifies the mixing ratio of the fuel elements to be reused, the reloading speed and frequency, and the circulation path and discharge rules of each fuel element in the core, and other key information. These factors can significantly affect the operating state of the core, and in turn change the key parameters of the core.

[0046] When the proportion of the fuel elements to be reused in the reloading scheme is increased, the reactivity of the core can be changed, causing the neutron flux distribution to change. When the reloading speed is increased, the power of the core can fluctuate greatly in a short time.

[0047] In some embodiments, the fuel elements to be reused refer to low-enrichment fuel elements discharged from the pebble bed high-temperature gas-cooled reactor and not reaching the designed burnup, which can also be referred to as low-enrichment spent fuel elements. The number of the fuel elements to be reused determines the scale of the fuel that can be reused by the subsequent fuel elements to be reused, and the burnup of the fuel elements to be reused reflects the degree of use of the fuel elements, and the lower the burnup, the more fissile material remaining in the fuel elements to be reused, and the greater the potential for participating in the reaction in the core.

[0048] As an example, the burnup of the fuel elements to be reused is not more than 57 GWd / tU, for example, the burnup of the fuel elements to be reused is between 18 GWd / tU and 57 GWd / tU.

[0049] It should be noted that the fuel elements to be reused can be low-enrichment spent fuel elements discharged from the current pebble bed high-temperature gas-cooled reactor and not reaching the designed burnup, or can be low-enrichment spent fuel elements discharged from other pebble bed high-temperature gas-cooled reactors and stored. In addition, the discharged low-enrichment spent fuel elements need to be stored in a shielded spent fuel tank for a period of time to reduce the radioactivity level for subsequent transfer and reuse into the reactor.

[0050] S2, based on the core model and the selected core reloading scheme, calculates the key parameters of the core under multiple working conditions, judges whether the key parameters of the core belong to the safe range, and in the case that the key parameters of the core belong to the safe range, according to the selected core reloading scheme, the fuel elements to be reused are loaded into the core to form an initial loading core.

[0051] It can be understood that the safety judgment is not based on a single key parameter, but a comprehensive consideration of multiple parameters. Because the physical processes in the core are interrelated and interdependent, an abnormality in one parameter can trigger a chain of changes in other parameters.

[0052] As an example, if the local power of the core is too high, it will cause the temperature of the fuel elements in the region to rise, which may in turn cause changes in the temperature and pressure of the coolant. If only the temperature of the fuel elements is considered and the changes in the coolant parameters are ignored, the safety of the core may not be comprehensively and accurately evaluated. Therefore, a comprehensive evaluation system needs to be established, in which the key parameters of the core, such as the power distribution of the core, the temperature distribution, the gas pressure, the burnup, the control rod position, and the neutron flux, are included for overall analysis and judgment. Only when all the key parameters meet the corresponding safety standards can the core be determined to be in a safe state.

[0053] Therefore, the step should also include: in the case that the key parameters of the core do not belong to the safe range, re-establishing the core model, and establishing the core refueling scheme of the pebble bed high-temperature gas-cooled reactor based on the re-established core model. Only when it is determined through calculation and judgment that the key parameters of the core belong to the safe range under multiple operating conditions, the selected core refueling scheme can be used to load the reused fuel elements into the core to form the initial load of the reactor.

[0054] In some embodiments, the multiple operating conditions can include, but are not limited to, full-power operating conditions, low-power operating conditions, and subcritical operating conditions, and the key parameters of the core can include, but are not limited to, the power distribution of the core, the temperature distribution, and the gas pressure. Using the core model and the refueling scheme, these parameters can be solved by corresponding calculation methods and software tools, so as to obtain a new refueling scheme of the pebble bed high-temperature gas-cooled reactor that meets the safety requirements, i.e., the selected core refueling scheme.

[0055] As an example, the calculation of the power distribution of the core can be based on a nuclear physics model, considering factors such as neutron flux distribution and fission reaction cross section of the fuel elements, to calculate the power generation of the fuel elements at different positions, thereby obtaining the power distribution of the entire core. For the temperature distribution, combined with a thermal-hydraulic model, the temperatures of the fuel elements, the coolant, and the core structure materials, etc. are calculated according to the power distribution of the core, the coolant flow rate, and the heat transfer coefficient, etc.

[0056] As an example, the calculation software of the core model and the refueling scheme of the pebble bed high-temperature gas-cooled reactor can select VSOP software.

[0057] In some embodiments, the step of loading the reused fuel elements into the core in the step further includes: loading graphite spheres and low-enrichment fuel elements into the core and mixing with the reused fuel elements at a preset ratio to form mixed fuel elements.

[0058] In the operation of a pebble bed high temperature gas cooled reactor, the core state will change with the operation stage. Therefore, in the initial core establishment and transition process, the fuel composition needs to be adjusted to meet the core reactivity and power requirements. Graphite balls mainly play the role of slowing down neutrons and occupying space; low enrichment fuel elements are used to provide initial fissile material and maintain the chain reaction; and reused fuel elements are used to improve nuclear fuel utilization and avoid resource waste. Mixing the three in a predetermined proportion to form a mixed fuel element can maintain a stable chain reaction in the core at different operation stages and ensure the safe and efficient operation of the reactor.

[0059] S3, driving the core to run, and obtaining the burnup of the reused fuel elements in the initial core through detection, and according to the core conversion scheme, the reused fuel elements that have not reached the design burnup are continuously loaded into the core and participate in the in-core cycle until the reused fuel elements are unloaded from the storage after reaching the design burnup.

[0060] It can be understood that, after the initial core is established and runs, a transition process is needed to reach a balanced core. The transition process from the initial core stage to the balanced core stage can include two stages. In the first stage, the core runs at a certain power, and the graphite balls in the mixed fuel elements in the core are unloaded in batches, while an equal amount of reused fuel elements are loaded, until the fuel elements in the core are completely composed of low enrichment fuel elements and reused fuel elements. In the second stage, the core starts to unload low enrichment spent fuel elements, including reused fuel elements that have reached the design burnup and low enrichment fuel elements, while loading high enrichment fuel elements, until the core is completely composed of high enrichment fuel elements, reaching the balanced core state.

[0061] By reloading the reused fuel elements that have not reached the design burnup into the core during the initial core and the first stage, the reused fuel elements continue to undergo fission reactions in the core, thereby optimizing the neutron flux distribution and power distribution of the core. Reasonable power distribution can reduce the hot spot temperature in local areas of the core, avoiding damage to the fuel elements and the core structure due to local overheating, thereby improving the safety and stability of the reactor operation. According to the conversion scheme, the proportion of reused fuel elements loaded and the number of cycles can be accurately controlled to better regulate the reactivity of the core, so that the reactor can maintain stable operation under different operating conditions. At the same time, the reused fuel elements that have not reached the design burnup still contain a large amount of unsplit nuclear fuel when they are first unloaded, and by reloading the reused fuel elements, the remaining nuclear fuel can be fully utilized, avoiding resource waste, thereby effectively improving the utilization rate of nuclear fuel.

[0062] Further, the fuel elements to be reused can also greatly reduce the demand for low-enrichment fuel elements and graphite spheres in the initial loading of the reactor and the transition process. Since the production, processing of new fuel elements (low-enrichment fuel elements) and the preparation of graphite spheres all require a large amount of cost, the use of fuel elements to be reused can reduce the procurement cost of this part and reduce the amount of spent fuel elements, thereby reducing the workload and cost of spent fuel reprocessing. In addition, spent fuel reprocessing involves complex process flow and high equipment investment, and reducing the amount of spent fuel can significantly reduce the cost in this regard and improve the economy of the reactor.

[0063] As an example, please refer to Figure 2 , Figure 2 is a schematic diagram of the change of discharge burnup of low-enrichment fuel elements of a pebble bed high-temperature gas-cooled reactor. As shown in Figure 2 , in the high-temperature gas-cooled reactor nuclear power plant demonstration project, this method can gradually increase the discharge burnup of low-enrichment fuel elements from a low initial level to the design burnup, thereby realizing efficient use of nuclear fuel.

[0064] In some embodiments, before the step of continuing to load the stored fuel elements to be reused which have not reached the design burnup into the reactor core according to the core loading and refueling scheme and participating in the in-core cycle in this step, the method comprises the following steps:

[0065] The graphite spheres in the mixed fuel elements are unloaded in batches by using the fuel loading and unloading system to form fuel vacancies in the reactor core. Thus, the stored fuel elements to be reused which have not reached the design burnup are continuously loaded into the fuel vacancies according to the core loading and refueling scheme to participate in the in-core cycle.

[0066] In summary, the method for reusing fuel elements based on a pebble bed high-temperature gas-cooled reactor provided in the present application first constructs a reactor core model containing fuel elements to be reused and a loading and refueling scheme based on the data of the fuel elements to be reused and the main design parameters of the pebble bed high-temperature gas-cooled reactor, then assembles an initial loading of the reactor after safety verification under multiple working conditions, and then continuously reuses the fuel elements to be reused which have not reached the design burnup in the reactor core until they reach the standard and are unloaded, thereby realizing safe and efficient reuse of fuel elements to be reused in the pebble bed high-temperature gas-cooled reactor. This method not only improves the utilization rate of nuclear fuel and reduces the operating cost, but also reduces the pressure of radioactive waste treatment, while ensuring the stability and safety of the reactor operation, which is of great significance to the economic and sustainable development of nuclear energy.

[0067] According to the second aspect of the present application, a system for reusing fuel elements based on a pebble bed high-temperature gas-cooled reactor is also provided, please refer to Figure 3 , Figure 3 is a block diagram of the system for reusing fuel elements based on a pebble bed high-temperature gas-cooled reactor provided in the embodiments of the present application. As shown in Figure 3 , the system comprises a model establishing module, a simulation calculation module, a first control module and a second control module.

[0068] a model establishing module, configured to establish a core model of a pebble bed high temperature gas-cooled reactor containing the fuel elements to be reused and a core reloading scheme based on a number of the fuel elements to be reused and burnup data and main design parameters of the pebble bed high temperature gas-cooled reactor;

[0069] a simulation calculation module, configured to calculate core key parameters in multiple working conditions based on the core model and the core reloading scheme and to determine whether the core key parameters are within a safety range;

[0070] a first control module, configured to load the fuel elements to be reused into the core to form an initial loading core according to the core reloading scheme if the core key parameters are within the safety range;

[0071] a second control module, configured to drive the core to run and to continue loading the fuel elements to be reused that are stored and have not reached a design burnup into the core and participate in in-core circulation according to the core reloading scheme until the fuel elements to be reused that have not reached the design burnup are unloaded after reaching the design burnup.

[0072] In some embodiments, the first control module is further configured to control a fuel loading and unloading system and load graphite spheres and low-enrichment fuel elements into the core to mix with the fuel elements to be reused at a preset ratio to form mixed fuel elements.

[0073] In some embodiments, the second control module is further configured to control the fuel loading and unloading system and unload the graphite spheres, the fuel elements to be reused that have reached the design burnup, and the low-enrichment fuel elements in the mixed fuel elements in batches by using the fuel loading and unloading system to form fuel vacancies in the core, and continue to load the fuel elements to be reused that have not reached the design burnup according to the core reloading scheme into the fuel vacancies to participate in in-core circulation.

[0074] In some embodiments, the model establishing module is further configured to reformulate the core model and the core reloading scheme if the core key parameters are not within the safety range.

[0075] It should be noted that the foregoing description of the embodiment of the method for reusing fuel elements of a pebble bed high temperature gas-cooled reactor is also applicable to the embodiment of the system for reusing fuel elements of a pebble bed high temperature gas-cooled reactor, which will not be described here again.

[0076] According to a third aspect of the present application, an electronic device is also provided. Please refer to Figure 4 , Figure 4 is a block diagram of the electronic device provided by the embodiment of the present application. As shown in Figure 4As shown, the electronic device 300 includes a processor 301 and a memory 302 connected with the processor 301 in communication; the memory 302 stores computer-executable instructions; and the processor 301 executes the computer-executable instructions stored in the memory to implement the method provided by the foregoing embodiments.

[0077] According to a fourth aspect of the present application, a computer-readable storage medium is further provided, and the computer-readable storage medium stores computer-executable instructions. The computer-executable instructions, when executed by a processor, implement the method provided by the foregoing embodiments.

[0078] According to a fifth aspect of the present application, a computer program product is further provided, and the computer program product includes a computer program. The computer program, when executed by a processor, implements the method provided by the foregoing embodiments.

[0079] The collection, storage, use, processing, transmission, provision and disclosure of user personal information involved in the present application comply with relevant laws and regulations and do not violate public order and good customs.

[0080] It should be noted that the personal information from the user should be collected for legal and reasonable purposes, and should not be shared or sold outside these legal uses. In addition, such collection / sharing should be carried out after the user's informed consent is received, including but not limited to informing the user to read the user agreement / user notice before the user uses the function, and signing the agreement / authorization including authorization of relevant user information. In addition, any necessary steps should be taken to protect and secure access to such personal information data, and to ensure that other people with access to personal information data comply with their privacy policies and processes.

[0081] The present application is expected to provide an embodiment in which the user can selectively prevent the use or access of personal information data. That is, the present disclosure is expected to provide hardware and / or software to prevent or block access to such personal information data. Once the personal information data is no longer needed, the risk can be minimized by limiting data collection and deleting data. In addition, such personal information is de-identified, as applicable, to protect the privacy of the user.

[0082] In the foregoing detailed description, reference is made to descriptive terms such as "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" etc. for describing various embodiments of the application. These descriptive terms are used for the purpose of the description and are not meant to limit or restrict the scope of the application. The use of these terms does not imply that the application is comprised of at least the described embodiments, or that the described embodiments are the only embodiments the application is comprised of. The scope of the application is not limited to the described embodiments, but is rather defined by the appended claims. In the description of the embodiments of the application, reference is made to the terms "one embodiment", "some embodiments", "an example", "a specific example" or "some examples" etc. which are meant to describe a particular feature, structure, material or characteristic included in at least one embodiment of the application. The illustrative description of these terms does not imply that the application is comprised of at least the described embodiments or that the described embodiments are the only embodiments the application is comprised of. In the description of the embodiments of the application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example described previously. Moreover, the described features, structures, materials or characteristics can be combined in any suitable manner in one or more embodiments or examples of the application. Furthermore, the described embodiments and features of the described embodiments can be combined with other embodiments or features of the described embodiments, unless such a combination is clearly not possible, or is technically infeasible.

[0083] Furthermore, the terms "first", "second", etc. are used herein only to describe a certain feature, structure, material, etc. and do not imply a relative importance or a specific order. Thus, a feature defined with "first" or "second" can implicitly or explicitly comprise at least one of this feature. In the description of the application, the meaning of "a plurality" is at least two, such as for example two, three or four, unless expressly specified otherwise.

[0084] Any process or method descriptions or blocks in flow charts or otherwise described herein represent code modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. The flow diagrams and / or method descriptions and / or block diagrams included herein can be understood as representing code modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process. The various embodiments of the application can be realized in hardware, software, or a combination of hardware and software. The software can be realized in a centralized fashion in one computer system or code, or in a distributed fashion where different elements are spread across several computer systems or code. Any code segment utilities can be implemented by processor executable instructions or code stored in a memory.

[0085] The logic and / or steps represented in the flowcharts and / or described herein, for example, can be considered as a sequence of executable instructions stored in a computer readable medium, which can be executed by an instruction execution system, apparatus or device, such as a computer-based system, processor- based system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions, or a combination thereof. For the purposes of this specification, a "computer readable medium" can be any apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable medium can specifically include the following, which are non-exhaustive list: electrical connection (electrical device having one or more wires), portable computer diskette (magnetic device), random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or Flash memory), optical fiber device, and portable compact disc read-only memory (CDROM). In addition, the computer readable medium can even be paper or other suitable medium upon which the program is printed, as the program can be electronically captured, for example, by optically scanning the paper or other suitable medium, then electronically converted into a form that can be edited, compiled, or interpreted, or otherwise processed in electronic form into an executable form suitable for use in the instruction execution system, apparatus or device.

[0086] It should be understood that parts of the present application can be implemented in hardware, software, firmware or a combination thereof. In the above embodiments, a plurality of steps or methods can be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. As in another embodiment, if implemented in hardware, any of the following technologies known in the art or their combination can be used: discrete logic circuit with logic gate circuit for implementing logic functions on data signals, application specific integrated circuit with suitable combination logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA), etc.

[0087] Those skilled in the art of the present technology can understand that all or part of the steps carried out by the above-mentioned embodiment methods can be completed by a program instructing the relevant hardware, and the program can be stored in a computer readable storage medium. When the program is executed, it includes one of the steps of the method embodiment or a combination thereof.

[0088] In addition, each of the functional units in the various embodiments of the present application can be integrated in one processing module, or each of the units can be physically present separately, or two or more units can be integrated in one module. The integrated module can be implemented in the form of hardware or in the form of a software functional module. When the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer readable storage medium.

[0089] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present application have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for reusing fuel elements based on a pebble bed high-temperature gas-cooled reactor, characterized in that, Includes the following steps: Based on the number and burnup data of the reusable fuel elements, as well as the main design parameters of the pebble bed high-temperature gas-cooled reactor, a core model and core refueling scheme for the pebble bed high-temperature gas-cooled reactor containing the reusable fuel elements are established. Based on the core model and the core refueling scheme, calculate the key core parameters under various operating conditions, determine whether the key core parameters are within the safe range, and if the key core parameters are within the safe range, load the reusable fuel elements into the core to form the initial stack according to the selected core refueling scheme. The reactor core is driven to operate, and the burnup of the reusable fuel elements in the initial reactor core is obtained by detection. According to the reactor core refueling plan, the reusable fuel elements that have not reached the design burnup are continued to be loaded into the reactor core and participate in the reactor cycle until the reusable fuel elements reach the design burnup and are unloaded from storage.

2. The method according to claim 1, characterized in that, The step of loading the reusable fuel element into the reactor core according to the core refueling scheme further includes: Graphite spheres and low-enrichment fuel elements are loaded into the reactor core and mixed with the reusable fuel elements in a preset ratio to form a hybrid fuel element.

3. The method according to claim 2, characterized in that, The refueling scheme includes at least the refueling speed, frequency, and mixing ratio of the mixed fuel element.

4. The method according to claim 2, characterized in that, Before the step of loading the stored reusable fuel elements that have not reached the design burnup into the reactor core and participating in the reactor cycle according to the core refueling scheme, the following steps are included: The graphite balls in the mixed fuel elements are unloaded in batches using the fuel loading and unloading system to create fuel vacancies in the reactor core; the stored reusable fuel elements that have not reached the design burnup are continuously loaded into the fuel vacancies according to the reactor core refueling scheme and participate in the reactor core cycle.

5. The method according to claim 1, characterized in that, The method further includes: If the key parameters of the reactor core are not within the safe range, the reactor core model and the reactor core refueling and replacement scheme shall be revised.

6. The method according to claim 1, characterized in that, The establishment of a core model and core refueling scheme for a pebble bed-type high-temperature gas-cooled reactor containing the reusable fuel elements includes: The core model and refueling scheme of the pebble bed high-temperature gas-cooled reactor were established using pebble bed high-temperature gas-cooled reactor core design software.

7. The method according to claim 1, characterized in that, The main design parameters include core power, core diameter and height, fuel element enrichment, and coolant inlet and outlet temperatures and flow rates.

8. The method according to claim 1, characterized in that, The various operating conditions include full-power operating condition, low-power operating condition, and subcritical operating condition, and the key core parameters include core power distribution, temperature distribution, and gas pressure.

9. The method according to claim 1, characterized in that, The reusable fuel elements consist of low-enrichment fuel elements that have not reached the target burnup, which are discharged during the transition of the pebble bed high-temperature gas-cooled reactor from the initial core loading to the stable operation of the balanced core. The target burnup of the low-enrichment fuel elements is not less than 57 GWd / tU.

10. A fuel element reuse system based on a pebble bed high-temperature gas-cooled reactor, characterized in that, include: The model building module is used to build a core model and core refueling scheme of the pebble bed high-temperature gas-cooled reactor containing the reusable fuel elements, based on the number and burnup data of the reusable fuel elements and the main design parameters of the pebble bed high-temperature gas-cooled reactor. The simulation calculation module is used to calculate key core parameters under various operating conditions based on the core model and the core refueling scheme, and to determine whether the key core parameters are within the safe range. The first control module is used to load the reusable fuel elements into the core to form an initial stack according to the core refueling scheme, provided that the key parameters of the core are within the safe range. The second control module is used to drive the operation of the reactor core, and based on the burnup of the reusable fuel elements loaded into the reactor core and the reactor core refueling scheme, to continue loading the stored reusable fuel elements that have not reached the design burnup into the reactor core and participate in the reactor cycle until the design burnup is reached and then unloaded and stored.

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