Control rod grouping and reactor starting method and system for high-temperature gas cooled reactor nuclear power station

Abstract

The invention discloses a high-temperature gas cooled reactor nuclear power station control rod grouping and reactor starting method and system, and relates to the field of high-temperature gas cooled reactor control, the method comprises the following steps: splitting a safety rod group in a high-temperature gas cooled reactor into x main safety rods and y starting safety rods, x + y being equal to the total rod number in the safety rod group; when the reactor is started, the main safety rod and the starting safety rod are lifted, and an interval exists between the lifting time of the main safety rod and the lifting time of the starting safety rod. The control rod grouping method can ensure that the provided reactivity compensation amount meets the requirements of in-reactor temperature rise and flexible operation of a fuel loading and unloading system on reactivity, lifting of the safety rod in the reactor starting process does not cause reactor criticality, accidents caused by maximum reactivity in the reactor starting process can be effectively coped, and the safety of the reactor is improved. The reactor starting safety is ensured.

Description

Technical Field

[0001] The invention relates to the field of high temperature gas-cooled reactor control, in particular to a method and system for grouping control rods and starting a reactor in a high temperature gas-cooled reactor nuclear power plant. Background Art

[0002] Compared with the early high-temperature gas-cooled reactor, the high-temperature gas-cooled reactor (HTR-PM) has basically the same composition and shape, but adopts a lower power density and an elongated core shape that is conducive to the dissipation of residual heat. The core consists of a cylindrical active area composed of spherical fuel elements, an outer graphite reflector layer and outer carbon bricks. Spherical fuel elements are installed in the cylindrical fuel area. Two independent reactivity control systems based on different working principles are set in the graphite side reflector layer close to the active area, namely the control rod system and the absorption ball shutdown system.

[0003] The HTR-PM control rod system consists of 24 control rods, which are divided according to their functions. Among them, 6 control rods are used as regulating rod groups, together with 6 safety rod groups as emergency shutdown rods, and together with another 12 compensation rods to achieve cold shutdown. The control rods and absorber balls can achieve lower shutdown temperatures. During normal operation, the 6 safety rods are always raised out of the reactor, and the 6 regulating rods are responsible for reactivity regulation within the power range of 100% to 50%. Reactivity regulation below 50% power requires the participation of compensation rods. In addition, the control rods are also used for reactivity regulation under conditions such as reactor startup and power increase and decrease.

[0004] During the HTR-PM power test phase, it was found that due to the high core bypass ratio and the need to appropriately increase the core backup reactivity to meet the flexible operation requirements of the fuel loading and unloading system, there was a risk of raising the safety rods to criticality during the reactor startup process. To solve the above problems, it is necessary to optimize the control rod grouping and the reactor startup process. Summary of the invention

[0005] In view of the above-mentioned problems, the present invention is proposed.

[0006] Therefore, the problem to be solved by the present invention is that due to the high ratio of core bypass flow and the need to appropriately increase the core backup reactivity to meet the flexible operation requirements of the fuel loading and unloading system, there is a risk of raising the safety rod to criticality during the startup of the reactor.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: a method for grouping control rods of a high-temperature gas-cooled reactor nuclear power plant and starting a reactor, which includes splitting a safety rod group in a high-temperature gas-cooled reactor into x main safety rods and y starting safety rods, where x+y is equal to the total number of rods in the safety rod group; when the reactor is started, lifting the main safety rods and the starting safety rods, and there is an interval between the lifting times of the main safety rods and the starting safety rods.

[0008] As a preferred solution of the control rod grouping and reactor startup method of the high temperature gas-cooled reactor nuclear power plant of the present invention, the control rod system of the high temperature gas-cooled reactor includes a regulating rod group, a safety rod group and a compensating rod group.

[0009] As a preferred solution of the control rod grouping and reactor startup method for a high temperature gas-cooled reactor nuclear power plant of the present invention, the main safety rods and the startup safety rods are symmetrically distributed around the high temperature gas-cooled reactor.

[0010] As a preferred scheme of the control rod grouping and reactor startup method of a high-temperature gas-cooled reactor nuclear power plant described in the present invention, wherein: when the reactor is started, lifting the main safety rods and the startup safety rods includes raising the core temperature to a preset temperature; lifting x main safety rods to the upper limit position in sequence; and symmetrically lifting y startup safety rods to the upper limit position.

[0011] As a preferred solution of the control rod grouping and reactor startup method for a high-temperature gas-cooled reactor nuclear power plant described in the present invention, when the starting safety rod is being lifted, if the starting safety rod has not all reached the upper limit position, but the reactor has been critical, the starting safety rod continues to be lifted to the upper limit position to perform normal power increase operations.

[0012] As a preferred solution of the control rod grouping and reactor startup method of a high-temperature gas-cooled reactor nuclear power plant described in the present invention, when the startup safety rods are being lifted, if all the startup safety rods reach the upper limit but the reactor is still not critical, then other control rods continue to be lifted to reach criticality; the other control rods include an adjusting rod group and a compensating rod group.

[0013] Another object of the present invention is to provide a control rod grouping and reactor startup system for a high temperature gas-cooled reactor nuclear power plant, which ensures safe startup by adjusting the lifting action of the control rods when the high temperature gas-cooled reactor is started.

[0014] In order to solve the above technical problems, the present invention provides the following technical solutions: A system for control rod grouping and reactor startup method of a high temperature gas-cooled reactor nuclear power plant, comprising: a temperature monitoring module and a control module;

[0015] The temperature monitoring module is used to monitor the core temperature. When the core temperature reaches a preset temperature value, the information is transmitted to the control module. The control module is used to control the lifting action of the safety rod group, the regulating rod group and the compensating rod group.

[0016] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of the control rod grouping and reactor startup method of a high temperature gas-cooled reactor nuclear power plant are implemented.

[0017] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of the control rod grouping and reactor startup method for a high-temperature gas-cooled reactor nuclear power plant as described above.

[0018] The beneficial effects of the present invention are as follows: the control rod grouping method of the present invention can ensure that the reactivity compensation amount provided meets the reactivity requirements of the temperature increase in the reactor and the flexible operation of the fuel loading and unloading system. Lifting the safety rod during the reactor startup process will not cause the reactor to be critical. It can also effectively deal with the maximum reactivity introduction accident during the reactor startup process, ensuring the safety of the reactor startup. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0020] Figure 1 This is a control rod distribution diagram of the control rod grouping and reactor startup method of the high temperature gas-cooled reactor nuclear power plant in Example 1.

[0021] Figure 2 This is a startup flow chart of the control rod grouping and reactor startup method of a high temperature gas-cooled reactor nuclear power plant in Example 1.

[0022] Figure 3 This is a module structure diagram of the control rod grouping and reactor startup system of a high temperature gas-cooled reactor nuclear power plant in Example 2. DETAILED DESCRIPTION

[0023] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0025] Example 1, reference Figure 1 and Figure 2, which is the first embodiment of the present invention, and provides a control rod grouping and reactor startup method for a high-temperature gas-cooled reactor nuclear power plant, including: a control rod system of a high-temperature gas-cooled reactor includes a regulating rod group, a safety rod group and a compensating rod group. In this embodiment, the control rod system includes 24 control rods, of which 6 control rods are used as a regulating rod group, and together with 6 safety rod groups, they are used as emergency shutdown rods, and together with the other 12 compensating rods, a cold shutdown is achieved.

[0026] In an optional embodiment, the 6 safety rods are divided into 4 main safety rods and 2 start-up safety rods. The 2 start-up safety rods are still powered by the shutdown circuit breaker and have the function of emergency power-off rod drop. After the change, the control rods are divided into 6 safety rods (4 main safety rods and 2 start-up safety rods), 6 adjustment rods and 12 compensation rods. The specific scheme is shown in Table 1.

[0027] To ensure uniform core power distribution after the control rod grouping is changed, the two start-up safety rods are spaced 180° apart, and the remaining four main safety rods are evenly distributed on both sides of the start-up safety rod. For details on the control rod distribution after the change, see Figure 1 shown.

[0028] Table 1 Control rod adjustment group table

[0029]

[0030] In an optional embodiment, the six safety rods can also be divided into three main safety rods and three starting safety rods. In order to meet the requirement that the main safety rods and the starting safety rods are symmetrically distributed around the high-temperature gas-cooled reactor, the three starting safety rods are spaced 120° apart, and the three main safety rods are evenly distributed beside the starting safety rod.

[0031] After the control rod grouping is changed, the specific process of reactor startup operation is as follows: Figure 2 As shown:

[0032] S1. Raise the core temperature to a preset temperature (eg, above 150°C).

[0033] S2. Raise the main safety rods to the upper limit position one by one.

[0034] S3. Lift the start safety rod symmetrically to the upper limit position.

[0035] S4. If the starting safety rod has not reached the upper limit, but the reactor has reached criticality, continue to lift the starting safety rod to the upper limit and perform normal power increase operations.

[0036] S5. If all the safety rods have reached the upper limit, but the reactor is still not critical, continue to lift the other 18 control rods (6 regulating rods and 12 compensating rods) to reach criticality.

[0037] The present invention can achieve the following objectives by changing the control rod grouping and the start-up operation:

[0038] Reactivity compensation meets actual needs: After the control rod grouping is optimized, the main safety rod is located at the upper limit before the reactor is started, and the startup safety rod is located at the lower limit. The core reactivity compensation can be performed by starting the safety rod. The high-temperature gas-cooled reactor has a temperature negative feedback characteristic. When the reactor startup temperature is increased from 150°C to about 180°C, negative reactivity can be introduced during the startup phase to further increase the reactivity compensation. The core reactivity compensation provided by the two together is greater than the high core bypass ratio and the core backup reactivity that needs to be increased to meet the flexible operation requirements of the fuel loading and unloading system.

[0039] Reactivity compensation meets safety requirements: Changes in control rod grouping can balance the value of six safety rods in the core state on the basis of reactivity compensation meeting actual needs, and still ensure that the 150°C cold shutdown subcriticality meets design requirements.

[0040] Meeting the emergency shutdown requirements during the startup process: After the control rod grouping is optimized, when an emergency shutdown occurs during the startup process, assuming that one of the main safety rods located at the top of the stack fails to fall normally due to the determined rod jamming mechanism, and on this basis, assuming that one safety rod is stuck due to unpredictable factors, the remaining main safety rods can fall reliably, and the negative reactivity provided can still meet the emergency shutdown reactivity requirements after deducting 10% uncertainty, ensuring that the reactor safely enters the subcritical state.

[0041] In summary, dividing the safety rod into the main safety rod and the starting safety rod allows the starting safety rod to be raised to criticality, and combined with raising the reactor starting temperature to 180°C, it can meet the needs of increased reactivity in reactor power operation and cope with accidents introduced by maximum reactivity during the startup process.

[0042] Example 2, reference Figure 3 , which is the second embodiment of the present invention, and is different from the first embodiment in that: a system for control rod grouping and reactor startup method of a high-temperature gas-cooled reactor nuclear power plant, including a temperature monitoring module 100 and a control module 200; the temperature monitoring module 100 is used to monitor the core temperature, and when the core temperature reaches a preset temperature value, the information is transmitted to the control module 200; the control module 200 is used to control the lifting action of the safety rod group, the regulating rod group and the compensation rod group.

[0043] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0044] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0045] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0046] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0047] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for grouping control rods and starting a reactor in a high temperature gas-cooled reactor nuclear power plant, characterized in that: include, The safety rod group in the high temperature gas-cooled reactor is divided into x main safety rods and y startup safety rods, where x+y is equal to the total number of rods in the safety rod group; When the reactor is started, the main safety rod and the startup safety rod are lifted, and there is an interval between the lifting times of the main safety rod and the startup safety rod.

2. The method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to claim 1, characterized in that: The control rod system of the high temperature gas-cooled reactor comprises a regulating rod group, a safety rod group and a compensating rod group.

3. The method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to claim 2, characterized in that: The main safety rod and the startup safety rod are symmetrically distributed around the high temperature gas-cooled reactor.

4. The method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to claim 3, characterized in that: When the reactor is started, raising the main safety rod and the start-up safety rod includes raising the core temperature to a preset temperature; Lift x main safety rods to the upper limit position in sequence; Lift the Y starting safety rods symmetrically to the upper limit position.

5. The method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to claim 4, characterized in that: When the starting safety rod is being lifted, if the starting safety rod has not completely reached the upper limit position, but the reactor has been critical, the starting safety rod will continue to be lifted to the upper limit position to perform a normal power increase operation.

6. The method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to claim 5, characterized in that: When the start-up safety rods are lifted, if all the start-up safety rods reach the upper limit but the reactor is still not critical, other control rods are continued to be lifted to reach criticality; The other control rods include a regulating rod group and a compensating rod group.

7. A system using the control rod grouping and reactor startup method for a high temperature gas-cooled reactor nuclear power plant according to any one of claims 1 to 6, characterized in that: It comprises a temperature monitoring module (100) and a control module (200); The temperature monitoring module (100) is used to monitor the core temperature, and when the core temperature reaches a preset temperature value, the information is transmitted to the control module (200); The control module (200) is used to control the lifting actions of the safety rod group, the adjustment rod group and the compensation rod group.

8. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to any one of claims 1 to 6 are implemented.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for control rod grouping and reactor startup of a high temperature gas-cooled reactor nuclear power plant according to any one of claims 1 to 6 are implemented.

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