Protection system of nuclear power plant including small modular reactor in which common cause failure is eliminated

Abstract

The present invention relates to a protection system of a nuclear power plant including a small modular reactor in which common cause failure is eliminated, wherein: the small modular reactor includes a first reactor and a second reactor; the protection system receives an input of a state signal from each of the reactors, and determines whether to trip the reactor or to actuate an engineered safety feature actuation system (ESFAS) device; the first reactor and the second reactor each include a first channel and a second channel, and each of the channels includes a comparison logic processor and a coincidence logic processor; and at least one of the first channel and the second channel comprises an engineered safety feature actuation system auxiliary relay (ESFAS AR) including an analog configuration and a comparison logic process implemented by an ASIC.

Description

Protection system for nuclear power plants including small modular reactors with common-cause failures excluded

[0001] The present invention relates to a protection system for a nuclear power plant including a small modular reactor in which common cause failures are excluded.

[0002] The reactor protection systems used in commercial nuclear power plants are divided into plant protection systems comprised of analog components like relays and digital reactor protection systems comprised of digital devices. Because digital reactor protection systems involve software, quantifying their reliability is difficult and they are susceptible to common-cause failures. Therefore, a separate, diverse protection system must be established to address common-cause failures.

[0003] Unlike large reactors, small modular reactors (SMRs) are designed to house multiple small reactors within a single power plant. Consequently, the reactor protection system (RPS) also increases with the number of modules. Therefore, a highly reliable RPS that eliminates common-cause failures is required.

[0004] Accordingly, the purpose of the present invention is to provide a protection system for a nuclear power plant including a small modular reactor in which common cause failures are excluded.

[0005] The above object of the present invention is achieved by providing a protection system for a nuclear power plant including a small modular reactor in which common cause failures are excluded, wherein the small modular reactor includes a first reactor and a second reactor, and the protection system receives status signals of each reactor and determines whether the reactor is shut down or an engineering safety equipment operation system device is in operation, wherein the first reactor and the second reactor each include a first channel and a second channel, and each channel includes a comparison logic processor and a simultaneous logic processor, and wherein at least one of the first channel and the second channel includes an engineering safety equipment auxiliary relay (ESFAS AR) formed by a comparison logic processor implemented as an ASIC and an analog configuration.

[0006] The first channel includes a first sub-channel and a second sub-channel positioned in parallel, the first sub-channel includes the ASIC and the engineered safety equipment auxiliary relay, and the second sub-channel may be implemented digitally.

[0007] In the first sub-channel, the simultaneous logic processor and the initiation circuit may be formed of an analog configuration including a relay.

[0008] The second channel includes a configuration of a first sub-channel and a second sub-channel similar to the first channel, and the first sub-channel of the first channel may not communicate with the second sub-channel of the second channel, and the second sub-channel of the first channel may not communicate with the first sub-channel of the second channel.

[0009] The simultaneous logic processor of the first sub-channel of the first channel can communicate with the first sub-channel of the second channel through a relay contact.

[0010] The above second sub-channel can be configured based on either a PLC or an FPGA.

[0011] The first channel may include the ASIC and the engineered safety equipment auxiliary relay, and the second channel may be implemented digitally.

[0012] In the above first channel, the simultaneous logic processor and the initiation circuit may be implemented as an ASIC.

[0013] The above second channel can be configured based on either a PLC or an FPGA.

[0014] The simultaneous logic processor of the first channel can communicate with the second channel.

[0015] According to the present invention, a protection system for a nuclear power plant including a small modular reactor in which common cause failures are excluded is provided.

[0016] Figure 1 shows the configuration of a protection system of a nuclear power plant according to one embodiment of the present invention.

[0017] Figures 2 and 3 illustrate a first form of a protection system of a nuclear power plant according to one embodiment of the present invention.

[0018] Figures 4 and 5 illustrate a second form of a protection system of a nuclear power plant according to one embodiment of the present invention.

[0019] Figure 6 shows a third form of a protection system of a nuclear power plant according to an embodiment of the present invention.

[0020] Figure 7 illustrates a fourth form of a protection system of a nuclear power plant according to one embodiment of the present invention.

[0021] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0022] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0023] In addition, the size and thickness of each component shown in the drawing are arbitrarily shown for convenience of explanation, so the present invention is not necessarily limited to what is shown.

[0024] The reactor of the present invention is an integral reactor or a small modular reactor (SMR) in which a core and a steam generator are housed within the reactor.

[0025] The reactor protection system receives individual status signals from the reactor and determines the operating conditions of the reactor shutdown or engineering safety equipment operation system devices, and the nuclear power plant executes the reactor shutdown or engineering safety equipment operation system devices based on this determination.

[0026] The reactor protection system (RPS) has multiple input and decision channels. Each channel includes a comparison logic processor and a concurrent logic processor. The comparison logic processor receives variable inputs and compares them with fixed / variable setpoints. If the setpoints are violated, it generates an initiation signal. These initiation signals are then input to the concurrent logic processor from each operating channel and voted. The specific voting format can be selected according to the multi-design, such as 1 out of 2, 1 out of 3, 2 out of 3, or 2 out of 4.

[0027] In other words, the comparison logic processor processes the results compared with the corresponding setpoints to determine whether the power plant should be tripped. The concurrent logic processor gathers the results calculated on its own channel and those calculated on other channels and, based on selection logic such as 2 out of 4, generates the final power plant trip signal (RT) and the operating signals for the engineering safety equipment (ESFAS).

[0028] The present invention will be described with reference to the drawings below.

[0029] Referring to FIGS. 1 to 3, a first form of a protection system of a nuclear power plant according to an embodiment of the present invention is described.

[0030] FIG. 1 illustrates the configuration of a protection system of a nuclear power plant according to an embodiment of the present invention, and FIGS. 2 and 3 illustrate a first form of a protection system of a nuclear power plant according to an embodiment of the present invention.

[0031] The main control room controls multiple reactors (e.g., reactor 1, reactor 2, and reactor 3) via operator workstations. The number of reactors can range from 2 to 10. Each reactor is a small modular reactor.

[0032] There may be multiple driver workstations depending on the number of drivers, etc.

[0033] Each reactor includes a protection system, which generates plant trip signals (RTs) and engineering safety feature (ESFAS) activation signals. Figure 2 illustrates the protection system for a single reactor, and other reactors have protection systems with the same configuration.

[0034] The protection system consists of four channels, each of which includes a comparison logic processor (BP) and a concurrent logic processor (CP). In other embodiments, the number of channels in the protection system may be selected from two to eight. In the present invention, the multiple channels are denoted as the first channel, the second channel, or the A channel (CHA), the B channel (CHB), and so on.

[0035] Referring to Figure 2, each channel includes two subchannels arranged in parallel. For example, the first channel includes a first subchannel (A1) and a second subchannel (A2). The number of subchannels per channel can be selected from two to four.

[0036] Referring to Fig. 3, the comparison logic processor (BP1) in the first sub-channel (A1) is implemented as an ASIC, and the simultaneous logic processor (CP1), initiation circuit (iniciation circuit 1), and engineering safety equipment auxiliary relay (ESFAS AR) are implemented as an analog configuration including a relay.

[0037] The second sub-channel (A2) comprises a comparison logic processor (BP2) and a concurrent logic processor (CP2) that are both digitally configured, and more specifically, are implemented as a PLC or FPGA. The initiation circuit 2 of the second sub-channel (A2) can also be digitally configured and implemented as a PLC or FPGA.

[0038] Although not shown, other channels, such as the second channel and the third channel, may also have the same first sub-channel and second sub-channel configuration as the first channel.

[0039] Accordingly, not only the data (A1) of the comparison logic processor (BP1) of the first sub-channel (A1) but also the data (B1, C1, D1) of the comparison logic processor of the first sub-channel of another channel are input to the simultaneous logic processor (CP1) of the first sub-channel (A1). In addition, not only the data (A2) of the comparison logic processor (BP2) of the second sub-channel (A2) but also the data (B2, C2, D2) of the comparison logic processor of the second sub-channel of another channel are input to the simultaneous logic processor (CP2) of the second sub-channel (A2). Data communication between the first sub-channels can be performed through relay contacts.

[0040] In this way, in a protection system configuration in which the first sub-channel is an analog configuration and the second sub-channel is a digital configuration, the first sub-channel of the first channel does not communicate with the second sub-channel of another channel, and the second sub-channel of the first channel does not communicate with the first sub-channel of another channel.

[0041] The present invention, as described above, incorporates an analog configuration, eliminating common-cause failures. This increases the reliability of the protection system and eliminates or reduces the need for separate, diverse protection systems.

[0042] Figures 4 and 5 illustrate a second form of a protection system of a nuclear power plant according to one embodiment of the present invention.

[0043] Channels 1 and 3 include ASICs and engineered safety equipment auxiliary relays, with the comparison logic processor, simultaneous logic processor and initiation circuit implemented as ASICs.

[0044] The protection systems of the second and fourth channels are implemented digitally, just like the first type.

[0045] In the second form, the first and third channels, which include analog configurations, also have comparison logic processors implemented as ASICs, so that the simultaneous logic processors of each channel can receive data from other channels. In other words, the simultaneous logic processor of the first channel communicates with the second to fourth channels.

[0046] As described above, the present invention implements redundancy of analog-based and digital-based technologies within each channel of the reactor protection system to eliminate the possibility of common-cause failures and enhance reliability. Since each channel (or subchannel) consists of software-less ASIC modules and relays, software common-cause failures can be eliminated. By configuring the reactor protection system with digital modules, ASIC modules, and relays, common-cause failures can be completely eliminated, thereby enhancing the reliability of the reactor protection system.

[0047] In the first aspect of the present invention, a method for simultaneously securing redundancy and diversity within a single channel in a nuclear reactor protection system composed of multiple channels is provided. In each channel, the first subgroup comprises a comparison logic processor composed of an ASIC module, and the simultaneous logic and device operation logic are composed of relays, thereby eliminating common cause failures. The second subgroup comprises digital modules such as PLCs and FPGAs. In the second aspect, channels A and C are composed of analog-based technology, and channels B and D are composed of digital-based technology, thereby eliminating common cause failures.

[0048] In the first configuration, two subgroups, each with its own channel diversity, maintain independence without communicating with each other. A CIM (Component Interface Module) is provided for field device control, and the device is operated through the logic of a simultaneous logic processor based on operating signals received through subgroups 1 and 2.

[0049] The first and second forms described above can be used in combination with each other.

[0050] FIG. 6 illustrates a third form of a protection system of a nuclear power plant according to an embodiment of the present invention, and FIG. 7 illustrates a fourth form of a protection system of a nuclear power plant according to an embodiment of the present invention.

[0051] In the third form shown in Fig. 6, the simultaneous logic processor and the initiation circuit of the first sub-channel are implemented as an ASIC, compared to the first form.

[0052] In the fourth form shown in Fig. 7, the simultaneous logic processor and the initiation circuit of the first and third channels are configured analog, as compared to the second form.

[0053] According to the present invention, since common-cause failure factors are completely eliminated, the unavailability of the reactor protection system can be reduced, thereby increasing the reliability of the reactor protection system. In the first form, since subgroups are divided within the channel even from the system operation perspective, the situation in which the entire channel must be bypassed by maintaining only one subgroup of the channel can be eliminated. From the perspective of system reliability, there is an advantage in that the protection system can operate normally with 2 / 3 logic even when a common-cause failure occurs in a module of the same type and a channel of a different module is under maintenance. In addition, since the ASIC-based part includes fixed logic, the repetitive use of the same product is advantageous for maintenance, and other parts that are subject to frequent changes can be configured with relays, etc., thereby accommodating a variety of logic.

[0054] The above-described examples serve as illustrative examples of the present invention and are not intended to limit the scope of the present invention. Those skilled in the art will readily appreciate the potential for various modifications and implementations of the present invention. Therefore, the technical protection scope of the present invention should be defined by the appended claims.

Claims

1. In the protection system of a nuclear power plant including a small modular reactor where common cause failures are excluded, The above small modular reactor includes a first reactor and a second reactor, and the protection system receives status signals from each reactor and determines whether the reactor is shut down or the engineering safety equipment operation system equipment is in operation. The first reactor and the second reactor each include a first channel and a second channel, and each channel includes a comparison logic processor and a simultaneous logic processor. A protection system comprising at least one of the first and second channels, each of which includes an engineered safety equipment auxiliary relay (ESFAS AR) consisting of a comparison logic process implemented as an ASIC and an analog configuration.

2. In paragraph 1, The above first channel is, It includes a first sub-channel and a second sub-channel positioned in parallel, The above first sub-channel includes the ASIC and the engineered safety equipment auxiliary relay, The above second sub-channel is a protection system implemented digitally.

3. In paragraph 1, In the above first subchannel, A protection system consisting of an analog configuration including a simultaneous logic processor and an initiation circuit and a relay.

4. In paragraph 3, The above second channel includes a configuration of a first sub-channel and a second sub-channel similar to the above first channel, The first sub-channel of the first channel does not communicate with the second sub-channel of the second channel, A protection system in which the second sub-channel of the first channel does not communicate with the first sub-channel of the second channel.

5. In paragraph 4, A protection system in which the simultaneous logic processor of the first sub-channel of the first channel communicates with the first sub-channel of the second channel through a relay contact.

6. In paragraph 5, The above second sub-channel is a protection system configured based on either a PLC or an FPGA.

7. In paragraph 1, The above first channel includes the ASIC and the engineered safety equipment auxiliary relay, The above second channel is a protection system implemented digitally.

8. In paragraph 7, In the above first channel, A protection system with a concurrent logic processor and initiation circuit implemented as an ASIC.

9. In paragraph 8, The above second channel is a protection system configured based on either a PLC or an FPGA.

10. In paragraph 9, The simultaneous logic processor of the first channel is a protection system that communicates with the second channel.

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