Reactor protection system using multiple coincidence processors

Abstract

The present invention relates to a reactor protection system, and the reactor protection system using multiple coincidence processors, according to an embodiment of the present invention, comprises: M channels equally receiving input signals of N mutually different items, wherein M and N are integers greater than 1; M coincidence processors that are respectively arranged in the M channels and receive the input signals of the N mutually different items; and bistable processors that are respectively arranged in the M channels and generate trip signals by receiving the processing results of the coincidence processors and performing bistable logic.

Description

Reactor protection system using multiple simultaneous logic processors

[0001] The present invention relates to a nuclear reactor protection system, and more particularly, to a nuclear reactor protection system using multiple simultaneous logic processors.

[0002] Figure 1 is a drawing for explaining the main configuration of a typical nuclear power plant (100). As illustrated in Figure 1, the primary system of the nuclear power plant (100) includes a reactor (130), a pressurizer (140), a coolant pump (150), and a steam generator (160), and the secondary system may include a turbine (170), a generator (180), a condenser (190), and a feedwater pump (191).

[0003] The reactor (130) generates heat of about 1000 degrees Celsius when the nuclear fuel (120) undergoes nuclear fission, thereby raising the temperature of the coolant to about 300 degrees Celsius. In the pressurizer (140), the coolant water is kept from boiling even at temperatures exceeding 100 degrees Celsius, and in the case of a light water reactor, the coolant is 160 kg / cm 2 Apply pressure of 110 kg / cm for the coolant in the case of heavy water reactors. 2 Apply pressure to it.

[0004] The coolant pump (150) performs the function of circulating the primary system coolant that has passed through the steam generator (160) from the reactor (130) back into the reactor (130). The steam generator (160) performs the boiler function of a thermal power plant, and transfers heat to the feedwater that comes in through the secondary system condenser (190) and feedwater pump (191) by the coolant of the primary system that has become hot, thereby converting the feedwater into steam. The steam generated in this way rotates the turbine (170), and accordingly, the generator (180) converts mechanical energy into electrical energy.

[0005] In order to monitor the health of each system while operating a nuclear power plant like this, various types of sensors are installed in the reactor system and the detection signals from the sensors are monitored to determine the status of the nuclear power plant.

[0006] During nuclear power plant operation, if a system malfunction that threatens reactor safety or a cooling malfunction within the nuclear steam supply system occurs, the reactor protection system detects these abnormalities and activates the reactor shutdown function by dropping the control rods. It also activates the engineering safety equipment operation system to cool the reactor. By performing these reactor protection functions, even if a nuclear power plant accident occurs, the plant remains safe and prevents the leakage of radiation and radioactive materials.

[0007] Therefore, the reactor protection system is a system that plays the most important role in the safety and reliability of nuclear power plants. In order to be applied to the power plant site, it must be a system with high reliability and high precision. In addition, when the reactor must be shut down, the reactor protection system must be able to perform the function of shutting down the reactor in any environment inside or outside the reactor protection system.

[0008] To this end, the reactor protection system is generally composed of multiple channels that perform the same function. In addition, the reactor protection system is composed of a signal input unit that acquires detection signals from sensors that measure various process variables and transmits them to multiple channels, a comparison logic unit that compares the acquired detection signals for each process variable with pre-stored set values, a simultaneous logic unit that generates a trip signal by combining the outputs of the comparison logic units of multiple channels when the sensor detection signals for each process variable in the comparison logic unit exceed the set value, and a stop initiation circuit that operates the reactor stop circuit or the engineering safety equipment operation circuit according to the stop signal output from the simultaneous logic unit.

[0009] Figures 2a and 2b are functional diagrams to briefly explain the concept of a conventional digital reactor protection system.

[0010] As illustrated in Fig. 2a, the digital reactor protection system (200) is composed of four channels (Channel A, B, C, D) (211, 212, 213, 214) with a redundancy structure. The number of channels may be four or more, but a four-channel redundancy structure is preferable in consideration of redundancy efficiency and circuit complexity. The remote shutdown room operator module and the main control room operator module (not shown) are connected to the four channels (211 to 214) to monitor and control the operating status of the reactor protection system.

[0011] In addition, the digital reactor protection system (200) is composed of a control device and a man-machine interface (MMI: Man-Machine Interface) related to testing / diagnosis, and an engineering workstation (EWS: Engineering Work Station) for initially loading the settings. The EWS is used to input the settings and related constants for each processor or hardware within the reactor protection system. The external system is composed of Tr. CPC, reactor trip device (RTSG), and engineering safety facility-component control system (ESF-CCS). Here, Tr can be expressed as PI (Process Instrument).

[0012] The above four channels (211 to 214) are operated completely independently from the sensor signal input terminal to the output terminal of each channel, and transmit the trip signals (240) for each process variable of the reactor systems output from the comparative logic processors (231 to 234) of each channel to the simultaneous logic processors (251 to 254) of the other channels through a communication method by the Safety Data Link (SDL) to exchange information between each channel. The sensor detection signals (220) for each process variable measured by the sensor include the pressure, flow rate, and water content of each system, the internal factor values ​​of the reactor calculated by the Core Protection Calculator (CPC), and the neutron flux output values ​​measured by the Ex-core Neutron Flux Monitoring System (ENFMS), and these values ​​are input independently for each channel.

[0013] Sensor detection signals (220) input to the input terminals of each channel (211 to 214) are transmitted to comparison logic processors (231 to 234) and compared with trip setpoints stored within the comparison logic processors (231 to 234). When a specific signal value exceeds the corresponding trip setpoint, the comparison logic processors (231 to 234) generate trip signals (240) for the corresponding variable. The generated trip signals (240) are transmitted to the respective simultaneous logic processors (251 to 254) in the four channels (211 to 214) via a safety data link.

[0014] The comparison logic processors (251 to 254) perform a 2 / 4 logic combination on the trip signals (240) for each process variable output from the comparison logic processors (231 to 234) in the 4 channels (211 to 214) and, if the logic is satisfied, that is, if the corresponding logic values ​​from 2 out of 4 channels are the same (Voting), generate a final trip signal (not shown) and transmit it to the initiation circuit (not shown). When the initiation circuit receives the final trip signal (not shown), it cuts off the control rod power through the reactor trip switch gear (RTSG) to stop the reactor due to the control rod dropping, and operates the engineered safety features-device control system (ESF-CCS) to cool the reactor.

[0015] Figure 2b is a functional diagram briefly illustrating the single-channel configuration of a conventional digital reactor protection system. As illustrated in Figure 2b, a single channel of a conventional digital reactor protection system is equipped with a comparison logic processor (280) and a simultaneous logic processor (290), which perform one of the overall protection logics of the reactor protection system.

[0016] As illustrated in FIG. 2b, sensor detection signals (270) input to the input terminal of channel A (260) are first transmitted to a comparison logic processor (280), and the comparison logic processor (280) compares the sensor detection signals (270) with a trip setting value stored within the comparison logic processor (280), and when a specific signal value among the sensor detection signals (270) exceeds the corresponding trip setting value, the comparison logic processor (280) generates a trip signal (281) for the corresponding variable and transmits it to a simultaneous logic processor (290) within the same channel.

[0017] The simultaneous logic processor (290) of channel A (260) simultaneously receives a trip signal (281) of a comparison logic processor (280) of the same channel and signal values ​​(282, 283, 284) from comparison logic processors (not shown) of each of the other channels (channel B, channel C, channel C) (282, 283, 284), performs a 2 / 4 logic combination, and when the logic is satisfied, that is, when the corresponding logic values ​​from two of the four channels are the same (Voting), generates a final trip signal (not shown) and transmits it to an initiation circuit (not shown).

[0018] The existing digital reactor protection system as described above has a structure in which the result of the comparison logic processor, i.e., the channel trip, is transmitted to the simultaneous logic processor, and the simultaneous logic processor votes to determine the final trip, requiring multiple processors for a single channel and the entire protection system, which increases the number of failure factors and, in particular, increases the probability of occurrence of a common cause failure mode.

[0019] In this way, the digital reactor protection system must be able to maximize reliability while utilizing an architecture that does not use concurrent logic processors to eliminate common cause failures of IEEE 603-1998.

[0020] [Prior Art Literature]

[0021] [Patent Document]

[0022] (Patent Document 1) Korean Patent Publication No. 10-0848881 (Digital Reactor Protection System, Samchang Enterprise)

[0023] An object of the present invention to solve the above-mentioned problems is to provide a reactor protection system capable of improving the reliability of diversity against common cause failure modes that may occur in a reactor protection system.

[0024] However, the problem to be solved by the present invention is not limited to this, and may be expanded in various ways without departing from the spirit and scope of the present invention.

[0025] According to one embodiment of the present invention, a nuclear reactor protection system using multiple concurrent logic processors may include M channels that receive input signals of N different items in the same manner, where M and N are integers greater than 1, M identical logic (Coinidence Processors) arranged in each of the M channels and receiving input signals of the N different items, and a comparison logic processor arranged in each of the M channels and receiving a processing result of the identical logic processor and performing comparison logic (Bistable Processor) to generate a trip signal.

[0026] The input signals of the N different items may include at least one of pressure, temperature, flow rate and radioactivity measured in the reactor.

[0027] Each of the simultaneous logical processors arranged in each of the M channels can equally receive the M input signals for each of the N different items.

[0028] Each of the simultaneous logic processors arranged in each of the above M channels can receive M × N input signals.

[0029] The simultaneous logic processors arranged in each of the M channels can generate intermediate values ​​for input signals for each identical item among the M × N input signals.

[0030] The simultaneous logic processors arranged in each of the M channels can transmit the generated intermediate values ​​to the comparison logic processors arranged in the same channel.

[0031] The number of intermediate values ​​transmitted from the simultaneous logic processor to the comparison logic processor may be equal to the number of input signals input to each of the M channels.

[0032] The generation of the above intermediate value may include sequentially sorting the values ​​of the input signals of the same item and finding the intermediate value among the sequentially sorted values ​​of the input signals of the same item.

[0033] The generation of the median may include sequentially sorting the values ​​of the input signals of the same item, and if two or more of the values ​​of the input signals of the same item sorted in the sequence are the same, finding a median from the values ​​of the input signals of the same item sorted in the sequence, and obtaining a conservative value from the median, and if two or more of the values ​​of the input signals of the same item sorted in the sequence are not the same, determining whether the number of channels is even, and if the number of channels is even, finding a median from the values ​​of the input signals of the same item sorted in the sequence excluding the maximum and minimum values, and obtaining a conservative value from the median, and if the number of channels is odd, obtaining a median from the values ​​of the input signals of the same item sorted in the sequence excluding the maximum and minimum values.

[0034] Finding a median in the values ​​of the input signals of the same item sorted in the above sequence, and obtaining a conservative value from the median may include removing the maximum and minimum values ​​from the values ​​of the input signals of the same item sorted in the above sequence, if there are duplicate maximum and minimum values, removing only one of the sorted values ​​first, and if there are values ​​with the same median value after removing the maximum and minimum values, selecting the one of the sorted values ​​first as the median.

[0035] The disclosed technology may have the following effects. However, this does not mean that a particular embodiment must include all or only the following effects, and thus the scope of the disclosed technology should not be construed as being limited thereby.

[0036] First, in the reactor protection system, the reliability of input signal values ​​can be improved by utilizing multiple sensor values ​​for specific signals without implementing simultaneous logic.

[0037] Second, in the reactor protection system, the reliability of the trip decision can be improved by obtaining the representative value of the sensor detection signal and using comparison logic.

[0038] Third, in the reactor protection system, the connection between simultaneous logic and comparative logic can be simplified, reducing the complexity of the system and improving the stability of the system.

[0039] Figure 1 is a drawing to explain the main components of a typical nuclear power plant.

[0040] Figure 2 is a functional diagram to briefly explain the concept of a conventional digital reactor protection system.

[0041] FIG. 3 is a functional configuration diagram briefly explaining a single channel configuration of a digital reactor protection system according to one embodiment of the present invention.

[0042] FIG. 4 is a functional diagram briefly explaining the concept of the overall operation of a digital reactor protection system according to one embodiment of the present invention.

[0043] FIG. 5 is a flowchart showing a process of acquiring an intermediate value performed within a concurrent logic processor according to one embodiment of the present invention.

[0044] The present invention is capable of various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and it is to be understood that all modifications, equivalents, and alternatives included within the technical spirit and scope of the present invention are included. In describing the present invention, if a detailed description of a related known technology is judged to obscure the gist of the present invention, the detailed description will be omitted.

[0045] Terms like "first" and "second" may be used to describe various components, but these terms do not limit the components themselves. These terms are used solely to distinguish one component from another.

[0046] The terminology used in this invention is solely for the purpose of describing specific embodiments and is not intended to limit the invention. The terminology used in this invention has been selected from widely used, current terms, taking into account the functions of the invention. However, this may vary depending on the intentions of those skilled in the art, precedents, or the emergence of new technologies. Furthermore, in certain cases, the applicant may arbitrarily select terms, in which case their meanings will be described in detail in the relevant description of the invention. Therefore, the terms used in this invention should not be defined simply as names of terms, but rather based on their meanings and the overall content of the invention.

[0047] Singular expressions include plural expressions unless the context clearly dictates otherwise. In the present invention, terms such as "comprise" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood not to preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0048] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. In describing with reference to the attached drawings, identical or corresponding components are assigned the same drawing numbers, and redundant descriptions thereof will be omitted.

[0049] FIG. 3 is a functional configuration diagram briefly explaining a single channel configuration of a digital reactor protection system according to one embodiment of the present invention.

[0050] As illustrated in FIG. 3, a single channel (310) constituting the digital reactor protection system of the present invention is equipped with a simultaneous logic processor (330) and a comparison logic processor (350), and performs one of the overall protection logics of the reactor protection system.

[0051] As illustrated in FIG. 3, the simultaneous logic processor (330) of channel A (310) is configured to receive both the process variable-specific sensor detection signals (P, T, F, N) (320) input to channel A (310) and the process variable-specific input sensor detection signals (P, T, F, N) (321, 322, 323) input to channels B, C, and D (331, 332, 333).

[0052] The simultaneous logic processor (330) acquires the median value (340) for each identical process variable from the sensor detection signals (320, 321, 322, 323) input to all channels according to the flow chart of FIG. 5 to be described later, and transmits the median value (340) to the comparison logic processor (350).

[0053] The comparison logic processor (350) compares the median value (340) for each process variable received from the simultaneous logic processor (330) with the pre-stored trip setting value for each process variable and outputs the final trip decision value (360).

[0054] FIG. 4 is a functional diagram briefly explaining the concept of the overall operation of a digital reactor protection system according to one embodiment of the present invention.

[0055] As illustrated in FIG. 4, the simultaneous logic processor (440) of channel A (410) of the reactor protection system (400) of the present invention receives all of the process variable-specific sensor detection signals (420) of channel A (410), the process variable-specific sensor detection signals (421) of channel B (411), the process variable-specific sensor detection signals (422) of channel C (412), and the process variable-specific sensor detection signals (423) of channel D (413). In the same manner, the simultaneous logic processors (441, 442, 443) of each channel (411, 412, 413) also receive all of the process variable-specific sensor detection signals (420, 421, 422, 423) of all channels (410, 411, 412, 413).

[0056] The simultaneous logic processors (440, 441, 442, 443) illustrated in FIG. 4 acquire the median values ​​(450, 451, 452, 453) of the sensor detection signals (P, T, F, N) for each process variable according to the flow chart of FIG. 5 to be described later, and transmit them to the comparison logic processors (460, 461, 462, 463).

[0057] Here, the number of intermediate values ​​transmitted from the simultaneous logic processors (440, 441, 442, 443) to the comparison logic processors (460, 461, 462, 463) is equal to the number of sensor detection signals input to each of the M channels.

[0058] The comparison logic processor (460, 461, 462, 463) compares the received intermediate values ​​(450, 451, 452, 453) with the preset trip setting values ​​for each process variable and outputs the final trip decision values ​​(470, 471, 472, 473).

[0059] FIG. 5 is a flowchart showing a process of acquiring an intermediate value performed within a comparison logic processor according to one embodiment of the present invention.

[0060] As illustrated in Figure 5, first, the simultaneous comparison logic integration processor sequentially sorts the values ​​input from multiple channels by process variable (S610). That is, the pressure (P), temperature (T), flow rate (F), and radiation (N) received from each channel are sequentially sorted.

[0061] Next, it is determined whether two or more of the same process variable values ​​input from multiple channels are the same (S620). In other words, it is determined whether two or more of the pressure (P) values ​​transmitted from multiple channels are the same.

[0062] If two or more identical values ​​exist, and if duplicate maximum and minimum values ​​exist when removing the maximum and minimum values ​​after sequential sorting, only one of the sorted values ​​is removed first, and if the median value exists after removing the maximum and minimum values, the one that was sorted first is selected as the median value (S630).

[0063] If two or more of the same process variable values ​​input from multiple channels are not the same value, it is determined whether the number of channels is an even number (S640).

[0064] In case there are an even number of channels, in step S610, the median value excluding the maximum and minimum values ​​is found from the values ​​sequentially sorted by process variable, and a conservative value is obtained from the median value (S650).

[0065] In step S640, if the number of channels is odd, the median value excluding the maximum and minimum values ​​is obtained from the values ​​sequentially sorted by process variable in step S610 (S660).

[0066] [Explanation of symbols]

[0067] 310, 331 to 333, 410 to 413: Channels

[0068] 320 to 323, 420 to 423: Sensor detection signals

[0069] 330, 440 to 443: Concurrent logical processors

[0070] 350, 460 to 463: Comparison logic processor

[0071] 360, 470 to 473: Trip decision values

Claims

1. A nuclear reactor protection system using multiple simultaneous logic processors, M channels receiving identical input signals of N different items, where M and N are integers greater than 1; The M simultaneous logic processors (Coincidence Processors) arranged in each of the M channels and receiving input signals of the N different items; and A nuclear reactor protection system using multiple simultaneous logic processors, comprising a comparison logic processor arranged in each of the above M channels and receiving the processing results of the simultaneous logic processors and performing comparison logic (Bistable Processor) to generate a trip signal.

2. In paragraph 1, A nuclear reactor protection system using multiple simultaneous logic processors, wherein the input signals of the N different items include at least one of pressure, temperature, flow rate and radioactivity measured in the nuclear reactor.

3. In paragraph 1, A nuclear protection system using multiple simultaneous logic processors, wherein each of the simultaneous logic processors arranged in each of the M channels receives the M input signals identically for each of the N different items.

4. In paragraph 1, A nuclear reactor protection system using multiple simultaneous logic processors, wherein each of the simultaneous logic processors arranged in each of the above M channels receives M × N input signals.

5. In paragraph 4, A nuclear reactor protection system using multiple simultaneous logic processors, wherein the simultaneous logic processors arranged in each of the above M channels generate intermediate values for input signals for each identical item among the M × N input signals.

6. In paragraph 5, A nuclear protection system using multiple simultaneous logic processors, wherein the simultaneous logic processors arranged in each of the above M channels transfer the generated intermediate values to the comparison logic processors arranged in the same channel.

7. In paragraph 6, A nuclear protection system using multiple simultaneous logic processors, wherein the number of intermediate values transmitted from the simultaneous logic processor to the comparison logic processor is the same as the number of input signals input to each of the M channels.

8. In paragraph 5, The generation of the above median is The values of the input signals of the same item are arranged sequentially, and if two or more of the values of the input signals of the same item arranged sequentially are the same value, the median value is found among the values of the input signals of the same item arranged sequentially, and a conservative value is obtained from the median value. If two or more of the values of the input signals of the same item sorted in the above sequence are not the same value, it is determined whether the number of channels is even, and if the number of channels is even, the median value excluding the maximum and minimum values from the values of the input signals of the same item sorted in the above sequence is found, and a conservative value is obtained from the median value. A nuclear protection system using multiple simultaneous logic processors, which comprises obtaining a median value excluding the maximum and minimum values from the values of the input signals of the same items sorted in the above sequence when the number of channels is odd.

9. In paragraph 8, Finding the median value among the values of the input signals of the same item sorted in the above sequence and obtaining a conservative value from the median value A nuclear protection system using multiple simultaneous logic processors, wherein when removing maximum and minimum values from the values of the input signals of the same item sorted in the above sequence, if there are duplicate maximum and minimum values, only one sorted value is removed first, and if there is a value with the same intermediate value after removing the maximum and minimum values, the first sorted one is selected as the intermediate value.

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