Nuclear power plant considering defense-in-depth levels

Abstract

The present invention relates to a nuclear power plant considering defense-in-depth levels, comprising: a plurality of reactors; common facilities that are jointly used by the plurality of reactors; and a measurement control system including a plurality of measurement control platforms corresponding to various operating conditions, wherein the measurement control system separately measures and controls the respective reactors and the common facilities.

Description

Nuclear power plants considering defense-in-depth levels

[0001] The present invention relates to a nuclear power plant taking into account a defense-in-depth stage.

[0002] Existing commercial nuclear power plants establish and operate an instrumentation and control architecture for related control and monitoring targets to efficiently respond to various operating conditions.

[0003] Conventional power plants usually operated with one reactor in mind, but with the introduction of small modular reactors, the operation of two or more reactors (modules, for example, four modules) became necessary, requiring the development of an instrumentation and control architecture that fits this need.

[0004] Accordingly, the purpose of the present invention is to provide a nuclear power plant that takes into account the defense-in-depth stage.

[0005] The above object of the present invention is to provide a nuclear power plant that takes into account a defense-in-depth stage, comprising a measurement and control system including a plurality of reactors; a common facility jointly used by the plurality of reactors; and a plurality of measurement and control platforms corresponding to various operating conditions, wherein the measurement and control system is achieved by separately measuring and controlling each of the reactors and the common facility.

[0006] The above reactor may include a small modular reactor.

[0007] The above common facilities may include plant auxiliary equipment (BOP).

[0008] Each of the above reactors and the above common facility may include a command system, an automatic control system, and a manual control system, respectively.

[0009] The above measurement and control platform is provided in two types, and at least one of them may be provided to have its own diversity.

[0010] The above various operating conditions include normal operation, abnormal operation, design basis accident, design basis exceeding accident, and serious accident, and the measurement and control platform may include DCS and FPGA.

[0011] The above abnormal operation includes a first abnormal operation that returns to a normal nuclear power plant and a second abnormal operation that responds to an expected operation event, and the DCS responds to the normal operation and the first abnormal operation, and the FPGA can respond to the second abnormal operation, the design basis accident, the design basis exceeding accident, and the severe accident.

[0012] The above measurement and control system can perform reactor control for the automatic control system of each reactor during the normal operation and the first abnormal operation, operate the reactor protection system for the second abnormal operation and the design basis accident, and perform common facility control for the automatic control system of the common facility during the normal operation and the abnormal operation, and operate the plant protection system for the design basis accident.

[0013] According to the present invention, a nuclear power plant is provided that takes into account the defense-in-depth stage.

[0014] Figure 1 illustrates the configuration of a nuclear power plant considering a defense-in-depth stage according to one embodiment of the present invention.

[0015] FIG. 2 illustrates an instrumentation and control architecture of a nuclear power plant considering a defense-in-depth stage according to one embodiment of the present invention.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] Figure 1 illustrates the configuration of a nuclear power plant considering a defense-in-depth stage according to one embodiment of the present invention.

[0020] As shown in Fig. 1, a nuclear power plant (1) includes an instrumentation and control system (10), a reactor (21, 22, 23...), and a common facility (30).

[0021] The instrumentation and control system (10) includes multiple instrumentation and control platforms. The reactors (21, 22, 23...) are provided in numbers of two or more, three or more, four or more, or five or more, and each reactor may be, but is not limited to, a small modular reactor (SMR).

[0022] The small modular reactor has a core and steam generator located inside the reactor vessel.

[0023] The common facility (30) is not provided for each reactor (21, 22, 23...), but represents a facility that is jointly used by each reactor (21, 22, 23...). For example, the common facility (30) may include a plant auxiliary equipment (BOP).

[0024] The instrumentation and control system (10) controls the indication system, automatic control system, and manual control system according to the operating status. The indication system, automatic control system, and manual control system are provided for each reactor (21, 22, 23...) and common facility (30).

[0025] An automatic control system is a system that automatically controls using logic when a given condition is reached, and a manual control system is a system that is manually controlled by an operator.

[0026] The present invention provides an instrumentation and control architecture in a nuclear power plant having a plurality of reactors as shown in FIG. 1, and this is described with reference to FIG. 2.

[0027] FIG. 2 illustrates an instrumentation and control architecture of a nuclear power plant considering a defense-in-depth stage according to one embodiment of the present invention.

[0028] The instrumentation and control system consists of two instrumentation and control platforms: a DCS and an FPGA. In other embodiments, other combinations of instrumentation and control platforms may be used.

[0029] Because only two types of instrumentation and control platforms are used, development / maintenance costs are reduced and optimal design is possible.

[0030] Here, the instrumentation and control platform is designed to have its own diversity. For example, FPGAs can use at least two different types: SRAM, Flash, and anti-fuse.

[0031] Through its own diversity, the existing diversity system (diversity protection system, diversity indication system, diversity manual operation switch) can be omitted.

[0032] The instrumentation and control system separately measures and controls each reactor (part A of Figure 5) and the common facility (part B of Figure 5). Each reactor and common facility each includes a command system, an automatic control system, and a manual control system.

[0033] The instrumentation and control system (I&C) changes its instrumentation and control platform or method based on various operating conditions. Operating conditions include normal operation, abnormal operation, design basis accidents, beyond-design basis accidents, and severe accidents. Specifically, the I&C system is divided into two categories: instrumentation and control targeting reactors (modules) at each defense-in-depth stage (normal, abnormal, design basis accidents, beyond-design basis accidents, severe accidents), and instrumentation and control targeting the entire power plant (as a shared facility within the power plant, multiple modules are jointly used).

[0034] In the present invention, “defense in depth” refers to having a means of responding to each stage of operation (normal operation, abnormality, design basis accident, design basis exceeding accident, major accident) by considering the expected state of the power plant.

[0035] Here, abnormal operation includes the first abnormal operation that returns to normal operation and the second abnormal operation that responds to expected operation events.

[0036] The first type of abnormal operation is an anticipated transient, which utilizes the control system to return the plant to normal operation within operating limits. The second type of abnormal operation is an anticipated operational transient, which, based on design criteria, trips the plant and returns it to a stable state. Different systems activate corresponding functions for anticipated transients and anticipated operational transients.

[0037] The first abnormal operation uses the control system used during normal operation to return the reactor to normal operation. The second abnormal operation is identical to the operation performed during a design basis accident, including power plant shutdown.

[0038] For the automatic control system of each reactor, reactor control is performed for normal operation and the first abnormal operation, and the reactor protection system is activated for the second abnormal operation and design basis accidents. For the automatic control system of the common facility, common facility control is performed for normal operation and abnormal operation, and the plant protection system can be activated for the design basis accident.

[0039] The measurement control of the present invention is described in detail below.

[0040] Reactor instrumentation and control

[0041] [Instruction system]

[0042] A screen that provides overall guidance (including device health) and support for module-level device and system operation (some parts of DL1 to DL2)

[0043] A screen that can be monitored to check the maintenance of power plant safety functions / physical barrier integrity in the event of abnormal (AOO), design basis accident (DL3a), and design basis exceeding accident (DL3b).

[0044] [Automatic Control]

[0045] Reactor control system that performs control on a module basis (automatic control such as process control, output control, and load following)

[0046] A reactor protection system that stops the reactor (module) and operates the engineering safety equipment to protect the power plant in the event of a design basis accident (DL3a) to make the power plant safe.

[0047] By applying a platform with diversity as a safety-grade platform, the diversity system introduced in existing digital commercial nuclear power plants is eliminated and used in the same way as that used in DL3a (DL3b can be seen as being integrated with DL3a and corresponding to DL3).

[0048] The system responding to a major accident (DL4) is being fluidly excluded, but if exclusion is not possible, the same system used in DL3 is being used.

[0049] [Manual control]

[0050] Reactor control system that performs control on a module basis (individual device control function is additionally provided to automatic control)

[0051] Since the return to normal operation from the abnormal (DL2) transient state does not consider manual operation, the reactor control system among the manual control functions is limited to normal operation (DL1).

[0052] Abnormal (DL2) and design basis accidents (DL3a) are considered as automatic operations, but DL3a has a hardwired switch as a final fallback.

[0053] Provides manual switches related to critical driver actions in design exceedance criteria accidents (DL3b).

[0054] Joint facility instrumentation and control

[0055] [Instruction system]

[0056] A screen (DL1~DL2) that provides overall instructions on equipment and system operation for the power plant's shared power plant (BOP) system.

[0057] A screen that can be monitored to confirm the maintenance of power plant safety functions / physical barrier integrity in the event of a design basis accident (DL3a) or design basis exceeding accident (DL3b).

[0058] There are no abnormal (AOO) events related to the shared system, meaning no response is required.

[0059] [Automatic system]

[0060] A joint control system (auxiliary system control) that performs control of jointly used devices

[0061] A joint protection system that stops the reactor (module) and operates the engineering safety equipment to protect the power plant in the event of a design basis accident (DL3a) related to the habitability of the control room used jointly at the power plant, thereby making the power plant safe.

[0062] [Manual system]

[0063] A joint control system that controls individual devices for a system (BOP) used jointly in a power plant (individual device control function is additionally provided to automatic control)

[0064] Manual response to abnormal (DL2) and design basis accidents for the common (joint use system) is not considered.

[0065] It is basically an automatic response to design criteria violations, but as a final fallback, it has a hardwired switch on the DL3a.

[0066] In the above embodiment, two types of measurement and control platforms, DCS and FPGA, are used and diversity is implemented in the FPGA. However, in other embodiments, the present invention is not limited to this and three or more measurement and control platforms may be used.

[0067] For example, FPGA / CPLD, PLC / FPGA, or PLC / CPLD can be introduced for abnormal, design basis accident, design exceedance accident, and major accident, respectively.

[0068] In another embodiment, abnormal and design basis accidents may be configured as FPGAs and design over-accidents and serious accidents may be configured as PLCs, or conversely, abnormal and design basis accidents may be configured as PLCs and design over-accidents and serious accidents may be configured as FPGAs.

[0069] Considering the characteristic of power plants being composed of multiple modules, a system capable of instrumentation and control for shared equipment is necessary. While it is possible to build a power plant by configuring each reactor (module) 100% independently, this can lead to operational disadvantages and difficult integrated management. Furthermore, SMRs are striving to expand and optimize shared systems to meet demand for electricity / hydrogen production and reduce costs. Therefore, designing an instrumentation and control system to efficiently manage this is essential. The present invention provides a technology that effectively instrumentes and controls multiple SMR modules.

[0070] According to the present invention, the platform is simplified by applying a single platform capable of inherent diversity for both design basis accidents and beyond-design basis accidents. By introducing a platform with inherent diversity, the use of diverse systems (such as diverse protection systems, diverse indicator systems, and diverse manual operation switches) can be eliminated.

[0071] In the present invention, considering the necessity of a safe system design through a defense-in-depth design and efficient operation management (reducing the number of platforms reduces the number of operating personnel, training, and self-management targets, and enables overall system optimization such as communication optimization), the number of platforms used in the entire power plant's instrumentation and control system is limited to two, and the system is designed with a minimum configuration.

[0072] The present invention enables efficient operation of a power plant by configuring an instrumentation and control system capable of operating multiple modules while considering defense-in-depth, and enables operation that reflects the characteristics of multiple units. To achieve this, the monitoring and control targets are divided into modules and the entire power plant.

[0073] By introducing a safety system platform with its own diversity, safety can be improved by configuring a robust instrumentation and control system by configuring the system and platform to be minimal in number and safely responding to all possible power plant situations.

[0074] 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 nuclear power plants considering the defense-in-depth stage, Multiple reactors; A common facility used jointly by the above plurality of reactors; and Includes an instrumentation and control system that includes multiple instrumentation and control platforms that respond to various driving conditions. The above measurement and control system is a nuclear power plant that measures and controls each reactor and the above common facility separately.

2. In paragraph 1, The above reactor is a nuclear power plant including a small modular reactor.

3. In paragraph 2, The above common facility is a nuclear power plant including a plant auxiliary equipment (BOP).

4. In paragraph 4, Each of the above reactors and the above common facilities, respectively, Nuclear power plant including command system, automatic control system and manual control system.

5. In paragraph 4, A nuclear power plant in which the above instrumentation and control platforms are provided in two types, at least one of which is provided to have its own diversity.

6. In paragraph 5, The above various driving conditions are, Includes normal operation, abnormal operation, design standard accidents, design standard exceeding accidents, and serious accidents. The above instrumentation and control platform is a nuclear power plant including DCS and FPGA.

7. In paragraph 6, The above abnormal operation includes the first abnormal operation that returns to normal operation and the second abnormal operation that responds to expected operation events. The above DCS corresponds to the above normal operation and the first abnormal operation, The above FPGA is a nuclear power plant that responds to the second abnormal operation, the design basis accident, the design basis exceeding accident, and the severe accident.

8. In paragraph 7, The above measurement and control system, For the automatic control system of each reactor above, For the above normal operation and the first abnormal operation, the reactor control is performed, and for the above second abnormal operation and the above design basis accident, the reactor protection system is operated. Regarding the automatic control system of the above common facility, A nuclear power plant that performs joint facility control during the above normal operation and above abnormal operation, and operates the plant protection system for the above design basis accident.

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