A method and system for generating a core undercooling margin low safety injection drive signal

Abstract

The present invention discloses a method and system for generating a core undercooling margin low safety injection drive signal, the method comprising respectively obtaining three undercooling margin low dry contact signals sent by two signal processing systems of a core measurement system; performing a two-out-of-three logic vote on the three undercooling margin low dry contact signals to generate a low undercooling margin signal; performing an AND logic operation on the undercooling margin signal, a P11 signal and a P15 non-signal to generate a safety injection drive signal. The present invention is designed with a function of automatically triggering safety injection due to low core undercooling margin in the reactor protection system, that is, when there is a P11 permission signal and no P15 permission signal, if the reactor coolant cooling margin is low, it is necessary to automatically start the safety injection, thereby ensuring the safety of the reactor.

Description

Technical Field

[0001] The present invention relates to the field of nuclear power plant instrumentation and control technology, and in particular to a method and system for generating a core undercooling margin low-safety injection drive signal. Background Art

[0002] The purpose of setting the low protection function of supercooling margin (△Tsat) in the reactor protection system is to protect the safety of the core and prevent the core from deviating from nucleate boiling (DNB) and the center melting of the fuel under Class I and Class II conditions. It uses reactor thermal measurement and nuclear measurement parameters to define the limits of reactor power, DNBR and core outlet without boiling when the reactor is operating at different average coolant temperatures (Tavg). These limits are reflected in the required value of the temperature difference (△Tsat) between the outlet and inlet of the reactor coolant loop (also called the △Tsat constant). If the actual measured inlet and outlet temperature difference △Tsat reaches or exceeds the △Tsat constant, the reactor emergency shutdown will be triggered. However, the current design of the reactor protection system does not consider the function of automatically triggering safety injection due to low core supercooling margin (△Tsat). Summary of the invention

[0003] Therefore, in order to realize the power of automatically triggering safety injection due to low core supercooling margin in the reactor protection system and improve the safety of the nuclear power plant, the present invention provides a method and system for generating a safety injection driving signal for low core supercooling margin. The present invention is designed with a function of automatically triggering safety injection due to low core supercooling margin in the reactor protection system, that is, when there is a P11 permission signal (pressurizer pressure is low by 2) and there is no P15 permission signal (hot section temperature is low by 1, reactor coolant flow is low by 2, and reactor coolant pressure is low by 1), if the reactor coolant cooling margin is low, it is necessary to automatically start the safety injection, thereby ensuring the safety of the reactor.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for generating a core undercooling margin low safety injection drive signal, comprising:

[0006] Respectively obtain three-way undercooling margin low dry contact signals sent by two signal processing systems of the core measurement system;

[0007] The three-way overcooling margin low dry contact signals are subjected to two-out-of-three logic voting to generate an overcooling margin low signal;

[0008] After performing a logical AND operation on the supercooling margin signal, the P11 signal and the P15 negation signal, an injection drive signal is generated.

[0009] As a preferred embodiment, the method of the present invention further comprises:

[0010] The safety injection drive signal output drives the dedicated driver action to execute the safety injection function.

[0011] As a preferred embodiment, the low supercooling margin dry contact signal of the present invention is designed to close the contact when the supercooling margin is low, and the low supercooling margin dry contact signal is powered by the reactor protection system before participating in downstream logic operations.

[0012] As a preferred embodiment, each logic series of the reactor protection system of the present invention provides three independent decoupling power supplies to respectively supply power to three undercooling margin low dry contact signals.

[0013] As a preferred embodiment, after each signal processing system of the present invention completes the calculation of the undercooling margin and compares it with the set value of the trigger safety injection, it outputs three undercooling margin low dry contact signals to the corresponding logic series of the reactor protection system.

[0014] In a second aspect, the present invention provides a core undercooling margin low safety injection drive signal generation system, including a core measurement system;

[0015] The core measurement system includes two signal processing systems, each of which outputs three undercooling margin low dry contact signals to the corresponding logic series of the reactor protection system for logic processing, and then outputs injection drive signals to drive the dedicated driver to operate.

[0016] In a third aspect, the present invention provides a core undercooling margin low safety injection drive signal generation system, including a reactor protection system;

[0017] The reactor protection system includes two logic series, each logic sequence receives three undercooling margin dry contact signals sent by the corresponding signal processing system of the core measurement system, and performs logic processing on the three signals to generate injection drive signals to drive the dedicated driver to operate.

[0018] In a fourth aspect, the present invention provides a core undercooling margin low safety injection drive signal generation system, comprising a core measurement system and a reactor protection system;

[0019] The core measurement system includes two signal processing systems, each of which outputs three undercooling margin low dry contact signals to the corresponding logic series of the reactor protection system;

[0020] The reactor protection system comprises two logic series, each of which performs logic processing on three received undercooling margin low dry contact signals to generate injection driving signals.

[0021] As a preferred embodiment, the low supercooling margin dry contact signal of the present invention is designed to close the contact when the supercooling margin is low, and the low supercooling margin dry contact signal is powered by the reactor protection system before participating in downstream logic operations.

[0022] As a preferred embodiment, each logic series of the reactor protection system of the present invention provides three independent decoupling power supplies to respectively supply power to three undercooling margin low dry contact signals.

[0023] The present invention has the following advantages and beneficial effects:

[0024] 1. The present invention improves the operational safety of nuclear power plants by adding a function of automatically triggering safety injection due to low coolant cooling margin in the reactor protection system.

[0025] 2. The present invention sends three △Tsat low dry contact signals to each logic series of the reactor protection system through the RII system. When △Tsat is low, the contacts are closed, and the reactor protection system distributes power to it before participating in downstream logic operations, thereby effectively reducing the probability of system malfunction.

[0026] 3. The present invention designs three independent decoupling power supplies for each logic series of the reactor protection system, which respectively power three △Tsat low dry contact signals, thereby ensuring that the reactor coolant △Tsat low safety injection function has a sufficiently low rejection rate and reduces its false operation probability as much as possible, thereby improving the safety of nuclear power plant operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0028] Figure 1 The figure is a schematic diagram of a method flow of an embodiment of the present invention.

[0029] Figure 2 This is Example 1 of a logic schematic diagram for generating a low-safety injection drive signal with a supercooling margin according to an embodiment of the present invention.

[0030] Figure 3 This is Example 2 of a logic schematic diagram for generating a low-safety injection drive signal with a supercooling margin according to an embodiment of the present invention.

[0031] Figure 4 4 is a system principle block diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0032] Hereinafter, the term "include" or "may include" used in various embodiments of the present invention indicates the presence of the invented function, operation or element, and does not limit the addition of one or more functions, operations or elements. In addition, as used in various embodiments of the present invention, the terms "include", "have" and their cognates are intended only to indicate specific features, numbers, steps, operations, elements, components or combinations of the foregoing items, and should not be understood as first excluding the presence of one or more other features, numbers, steps, operations, elements, components or combinations of the foregoing items or the possibility of adding one or more features, numbers, steps, operations, elements, components or combinations of the foregoing items.

[0033] In various embodiments of the present invention, the expression "or" or "at least one of A or / and B" includes any combination or all combinations of the words listed at the same time. For example, the expression "A or B" or "at least one of A or / and B" may include A, may include B, or may include both A and B.

[0034] The expressions (such as "first", "second", etc.) used in various embodiments of the present invention may modify the various constituent elements in various embodiments, but may not limit the corresponding constituent elements. For example, the above expressions do not limit the order and / or importance of the elements. The above expressions are only used for the purpose of distinguishing an element from other elements. For example, the first user device and the second user device indicate different user devices, although both are user devices. For example, without departing from the scope of various embodiments of the present invention, the first element may be referred to as the second element, and similarly, the second element may also be referred to as the first element.

[0035] It should be noted that if it is described that one component element is “connected” to another component element, the first component element may be directly connected to the second component element, and a third component element may be “connected” between the first component element and the second component element. Conversely, when one component element is “directly connected” to another component element, it can be understood that there is no third component element between the first component element and the second component element.

[0036] The terms used in various embodiments of the present invention are only used for the purpose of describing specific embodiments and are not intended to limit various embodiments of the present invention. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. Unless otherwise limited, all terms used here (including technical terms and scientific terms) have the same meaning as the meaning generally understood by those of ordinary skill in the art to which the various embodiments of the present invention belong. The terms (such as the terms defined in the dictionary generally used) will be interpreted as having the same meaning as the contextual meaning in the relevant technical field and will not be interpreted as having an idealized meaning or an overly formal meaning, unless clearly defined in various embodiments of the present invention.

[0037] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0038] Example 1

[0039] This embodiment proposes a method for generating a core subcooling margin low safety injection drive signal. In this method, the reactor protection system is designed with a function of automatically triggering safety injection due to low coolant subcooling margin (△Tsat). Specifically, when there is a P11 permission signal and no P15 permission signal, if the reactor coolant subcooling margin (△Tsat) is low, it is necessary to automatically start the safety injection to ensure the safety of the reactor.

[0040] like Figure 1 As shown, the method of this embodiment specifically includes the following steps:

[0041] S10, respectively obtaining three undercooling margin low dry contact signals sent by two signal processing systems of the core measurement system;

[0042] S20, performing a two-out-of-three logic vote on the three-way overcooling margin low dry contact signals to generate an overcooling margin low signal;

[0043] S30, performing an AND logic operation on the undercooling margin signal, the P11 signal and the P15 negation signal to generate an injection driving signal;

[0044] S40, outputting the safety injection driving signal to drive the dedicated driver to perform the safety injection function.

[0045] In the K2 / K3 nuclear power project, the calculation of the reactor coolant subcooling margin (△Tsat) is completed by a special core measurement system (RII system) based on DCS technology. The RII system is divided into two signal processing systems, column A and column B. After completing the calculation of △Tsat and comparing it with the set value for triggering the safety injection, each column of the RII system sends three △Tsat low dry contact signals to the corresponding logic series of the reactor protection system (RRP system), which corresponds to the three reactor coolant loops. The three signals are voted by the "2 / 3" (that is, three out of two) logic (that is, as long as two of the three signals are true) inside the reactor protection system. The △Tsat low signal generated is "ANDed" with the P11 signal and the P15 non-signal to generate the final safety injection drive signal. The relevant logic is as follows: Figure 2 shown.

[0046] Furthermore, in order to reduce the probability of system misoperation, the low supercooling margin dry contact signal sent by the core measurement system is designed to close the contact when the supercooling margin is low, and the reactor protection system distributes power to it before participating in downstream logic operations. However, this design may cause a refusal to operate due to loss of signal power supply. Therefore, in order to reduce the probability of system refusal to operate due to loss of signal power supply, three independent decoupling power supplies are designed for each logic series of the reactor protection system to supply power to the above three dry contact signals respectively, ensuring that the reactor coolant △Tsat low safety injection function has a sufficiently low refusal rate. The relevant logic is as follows: Figure 3 As shown, the protection logic processing is a protection logic processing cabinet in the reactor protection system, and the logic processing unit used is as follows Figure 2 As shown, the three-way low overcooling margin dry contact signals are subjected to a two-out-of-three logic vote to generate a low overcooling margin signal, and then the low overcooling margin signal is subjected to an AND logic operation with the P11 signal and the P15 non-signal to generate an injection drive signal; finally, the injection signal is output through the output module (DO) to drive the dedicated driver to operate. The technology proposed in the embodiment of the present invention not only ensures that the reactor coolant △Tsat low injection function has a sufficiently low rejection rate, but also reduces its false operation rate level as much as possible.

[0047] Example 2

[0048] This embodiment proposes a core undercooling margin low safety injection drive signal generation system, such as Figure 4 As shown, the system includes a core measurement system and / or a reactor protection system.

[0049] Among them, the core measurement system includes two signal processing systems (A series signal processing system and B series signal processing system); after each signal processing system completes the calculation of the subcooling margin and compares it with the set value of triggering the safety injection, it outputs three-way subcooling margin low dry contact signals to the corresponding logic series of the reactor protection system for logic processing and outputs the safety injection drive signal to drive the dedicated driver to operate.

[0050] The reactor protection system includes two logic series (logic series A and logic series B), and both logic series A and logic series B include a three-out-of-two logic unit, a NOT gate and an AND gate. The three-out-of-two logic unit performs a three-out-of-two logic vote on the three-way undercooling margin low dry contact signals output by the core measurement system to generate a low undercooling margin signal; the P15 signal passes through the NOT gate and is input into the AND gate with the P11 signal and the low undercooling margin signal to perform an AND logic operation to generate a safety injection drive signal.

[0051] Furthermore, the low subcooling margin dry contact signal sent by the core measurement system is designed so that when the low subcooling margin exists, the contact is closed, and the reactor protection system distributes power to it before participating in downstream logic operations.

[0052] Furthermore, since the contact closure and power distribution design may result in a rejection problem due to loss of signal power supply, in order to reduce the probability of system rejection due to loss of signal power supply, each logic series of the reactor protection system is designed with three independent decoupling power supplies to supply power to the above three dry contact signals respectively, ensuring that the reactor coolant △Tsat low safety injection function has a sufficiently low rejection rate.

[0053] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for generating a core undercooling margin low safety injection drive signal, characterized in that: include: Respectively obtain three-way undercooling margin low dry contact signals sent by two signal processing systems of the core measurement system; The three-way overcooling margin low dry contact signals are subjected to two-out-of-three logic voting to generate an overcooling margin low signal; After performing a logic AND operation on the undercooling margin low signal, the P11 signal and the P15 negation signal, an injection drive signal is generated.

2. A method for generating a core undercooling margin low safety injection driving signal according to claim 1, characterized in that: Also includes: The safety injection drive signal output drives the dedicated driver action to execute the safety injection function.

3. The method for generating a core undercooling margin low safety injection driving signal according to claim 1, characterized in that: The low supercooling margin dry contact signal is designed so that when the supercooling margin is low, the contact is closed, and the low supercooling margin dry contact signal is energized by the reactor protection system before participating in downstream logic operations.

4. A method for generating a core undercooling margin low safety injection driving signal according to claim 3, characterized in that: Each logic series of the reactor protection system provides three independent decoupling power supplies to supply power to three low overcooling margin dry contact signals respectively.

5. A method for generating a core undercooling margin low safety injection driving signal according to any one of claims 1 to 4, characterized in that: After each signal processing system completes the calculation of the undercooling margin and compares it with the set value of the trigger safety injection, it outputs three undercooling margin low dry contact signals to the corresponding logic series of the reactor protection system.

6. A core undercooling margin low safety injection drive signal generation system, characterized in that: Includes core measurement system; The core measurement system includes two signal processing systems, each of which outputs three-way undercooling margin low dry contact signals to the logic series corresponding to the reactor protection system for logic processing and then outputs injection drive signals to drive the dedicated driver to act; the logic processing includes: performing a two-out-of-three logic vote on the three-way undercooling margin low dry contact signals to generate a undercooling margin low signal; and performing an AND logic operation on the undercooling margin low signal, the P11 signal and the P15 negation signal.

7. A core undercooling margin low safety injection drive signal generation system, characterized in that: Includes reactor protection system; The reactor protection system includes two logic series, each logic sequence receives three undercooling margin dry contact signals issued by the corresponding signal processing system of the core measurement system, and performs logic processing on the three signals to generate injection drive signals to drive the dedicated driver to act; the logic processing includes: performing a two-out-of-three logic voting on the three undercooling margin low dry contact signals to generate a undercooling margin low signal; and performing an AND logic operation on the undercooling margin low signal, the P11 signal and the P15 negation signal.

8. A core undercooling margin low safety injection drive signal generation system, characterized in that: Includes core measurement system and reactor protection system; The core measurement system includes two signal processing systems, each of which outputs three undercooling margin low dry contact signals to the corresponding logic series of the reactor protection system; The reactor protection system includes two logic series, each logic series performs logic processing on three received low overcooling margin dry contact signals to generate an injection drive signal; the logic processing includes: performing a two-out-of-three logic voting on the three low overcooling margin dry contact signals to generate a low overcooling margin signal; and performing an AND logic operation on the low overcooling margin signal, the P11 signal and the P15 negation signal.

9. A core undercooling margin low safety injection drive signal generation system according to claim 8, characterized in that: The low supercooling margin dry contact signal is designed so that when the supercooling margin is low, the contact is closed, and the low supercooling margin dry contact signal is energized by the reactor protection system before participating in downstream logic operations.

10. A core undercooling margin low safety injection drive signal generation system according to claim 9, characterized in that: Each logic series of the reactor protection system provides three independent decoupling power supplies to supply power to three low overcooling margin dry contact signals respectively.

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