A nuclear power plant state feedback processing system

Abstract

The present application belongs to the technical field of nuclear power plant instrument control system, and particularly relates to a nuclear power plant state feedback processing system. The present application comprises a turbine bypass system and a reactor protection system, the turbine bypass system sends two signals to the reactor protection system respectively, the reactor protection system is provided with a first logic or and a second logic or, and the two signals are connected with the first logic or and the second logic or respectively. The present application simplifies the design logic, improves the signal response time, and reduces the unplanned shutdown risk caused by the unavailability of the turbine bypass system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nuclear power plant instrument control system, and particularly relates to a nuclear power plant state feedback processing system. BACKGROUND

[0002] In the prior art, there are control strategy researches on nuclear power station turbine bypass control system. By introducing the turbine bypass control system of Ling'ao nuclear power station, the control strategy and thought of the turbine bypass system are analyzed to provide reference for the design of the turbine bypass system of the nuclear power station. There are also reports on the analysis of the problem of over-power caused by the unexpected full opening of the turbine bypass drain trap valve during the full-power operation of the pressurized water reactor nuclear power station. On the basis of combining the process of the conventional island system, a logical improvement method for improving the reliability of the signal by modifying the DCS configuration is proposed.

[0003] There are control strategy analysis researches on the turbine bypass control system of the nuclear power station. The document provides the control strategy and thought of the turbine bypass system for reference in the design of the turbine bypass system. For the problem of over-power caused by the unexpected full opening of the turbine bypass drain trap valve during the actual operation of the nuclear power station, a logical improvement method for improving the reliability of the signal is proposed. However, none of the above documents mentions processing the state feedback signal of the nuclear power plant to reduce the risk of unplanned shutdown caused by the unavailability of the turbine bypass system.

[0004] In the prior art, the different drain valves of the turbine bypass system are divided into two series A and B, and the corresponding logical processing is implemented in the A and B series DCS cabinets. In the existing design of the turbine bypass system, the non-full opening signal of the manual isolation valve of the drain valve belongs to the A and B series DCS cabinets, while the non-high signal of the temperature difference large signal and the control temperature difference signal in the pressure mode is only implemented in the A series DCS cabinet. The non-full opening signal of the isolation valve corresponding to the A series drain valve, the non-high signal of the temperature difference large signal and the control temperature difference signal in the pressure mode are processed by "logical or" in the A series DCS cabinet to generate the unavailability signal of the A series turbine bypass system, which is sent to the reactor protection system by hardwiring. On the other hand, the non-high signal of the temperature difference large signal and the control temperature difference signal in the pressure mode is transmitted from the A series DCS cabinet to the B series DCS cabinet by network transmission, and the non-full opening signal of the isolation valve corresponding to the B series drain valve, the non-high signal of the temperature difference large signal and the control temperature difference signal in the pressure mode are processed by "logical or" in the B series DCS cabinet to generate the unavailability signal of the B series turbine bypass system, which is sent to the reactor protection system by hardwiring. In the reactor protection system, when the nuclear power is higher than a certain value and meets the turbine trip signal after a delay of 1s, if it also meets the unavailability signal of the turbine bypass system (triggered by either the A series or the B series), in order to avoid the reactor from continuing to run under the condition of power generation and demand imbalance, causing the temperature and pressure of the main loop to rise rapidly, an emergency shutdown protection action needs to be generated to protect the safety of the reactor.

[0005] Since the above-mentioned processing method exists network transmission of signals between DCS A / B column cabinets, and network signal transmission time is influenced by scanning period, scanning sequence, network load and other factors, if DCS network processing delay is too large, the required ''B column steam turbine bypass system unusable'' signal in 1s is not reversed, thereby causing reactor emergency shutdown. SUMMARY

[0006] The technical problem solved by the present application is to provide a nuclear power plant state feedback processing system, which simplifies the design logic, improves the signal response time, and reduces the unplanned shutdown risk caused by the steam turbine bypass system unusable.

[0007] The technical scheme adopted by the present application is as follows:

[0008] A nuclear power plant state feedback processing system comprises a steam turbine bypass system and a reactor protection system, the steam turbine bypass system sends two signals to the reactor protection system respectively, and the reactor protection system is provided with a first logic OR and a second logic OR, and the two signals are connected with the first logic OR and the second logic OR respectively.

[0009] The steam turbine bypass system comprises a manual isolation valve of A column discharge valve, a pressure mode temperature difference processor, a control temperature difference signal processor, and a manual isolation valve of B column discharge valve.

[0010] The manual isolation valve of the A column discharge valve and the manual isolation valve of the B column discharge valve output non-full opening signals respectively.

[0011] The pressure mode temperature difference processor outputs a pressure mode temperature difference large signal.

[0012] The control temperature difference signal processor outputs a control temperature difference signal non-high signal.

[0013] The manual isolation valve of the A column discharge valve, the pressure mode temperature difference processor and the control temperature difference signal processor constitute a first signal, which is connected with the first logic OR in the reactor protection system through hardwiring.

[0014] The manual isolation valve of the B column discharge valve, the pressure mode temperature difference processor and the control temperature difference signal processor constitute a second signal, which is connected with the second logic OR in the reactor protection system through hardwiring.

[0015] The first logic OR generates an A column steam turbine bypass system unusable signal, and the second logic OR generates a B column steam turbine bypass system unusable signal.

[0016] Compared with the prior art, the present application has the beneficial effects that:

[0017] (1) The nuclear power plant state feedback processing system provided by the application directly transmits state feedback signals, such as whether a turbine bypass system is available, a non-full opening signal of a manual isolation valve corresponding to a discharge valve, a large temperature difference signal in a pressure mode, and a non-high signal of a control temperature difference signal, to a reactor protection system through a hard-wired transmission mode, the state feedback signals are logically processed in the reactor protection system, and a corresponding turbine bypass unavailable signal is generated, which simplifies the design logic, improves the signal response time, and reduces the risk of unplanned shutdown caused by the turbine bypass system being unavailable.

[0018] (2) The nuclear power plant state feedback processing system provided by the application reduces the unit transient, improves the economy of the nuclear power plant, and reduces the time for restarting the reactor after shutdown at a certain power level; at the same time, shutdown without shutdown also reduces the burden on the operating personnel; the nuclear power plant turbine bypass system is used to deal with the operation transient of turbine tripping or shutdown without shutdown, and the temperature and pressure changes of the nuclear steam supply system caused by the large and rapid decrease of turbine load are reduced by directly discharging the main steam to the condenser, thereby avoiding reactor emergency shutdown.

[0019] (3) The nuclear power plant state feedback processing system provided by the application changes the transmission mode of the state signal representing whether the nuclear power plant turbine bypass system is available and the logical processing mode of the state signal, that is, for the following state signals representing whether the nuclear power plant turbine bypass system is available: a large temperature difference signal in a pressure mode and a non-high signal of a control temperature difference signal, the above two signals are each transmitted to the reactor protection system in two ways through a hard-wired mode, and the signal transmission between different series is cancelled; the non-full opening signals A and B of the manual isolation valves of the A and B column discharge valves are directly transmitted to the reactor protection system through a hard-wired mode; the "or logic" of the three state signals is realized in the reactor protection system, respectively, to generate A and B column turbine bypass system unavailable signals; this method effectively shortens the signal transmission time between different systems, avoids the reactor emergency shutdown caused by the signal interaction between the A and B columns in the original design logic, and improves the economy of the power plant operation. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A nuclear power plant state feedback processing system provided by the application is shown in the schematic diagram.

[0021] In the figure: 1: A column discharge valve manual isolation valve, 2: pressure mode temperature difference processor, 3: control temperature difference signal processor, 4: A column turbine bypass system unavailable, 5: B column turbine bypass system unavailable, 6: first logical or, 7: turbine bypass system, 8: reactor protection system, 9: hard-wired, 10: B column discharge valve manual isolation valve, 11: second logical or. DETAILED DESCRIPTION

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] During a nuclear power plant's transient operation where the reactor remains operational without shutting down, the main steam is directly discharged to the condenser via the turbine bypass system. This reduces the magnitude of temperature and pressure changes in the nuclear steam supply system caused by a rapid and significant drop in turbine load, thus preventing an emergency reactor shutdown. During this transient process, the availability of the turbine bypass system must be ensured. If the turbine bypass system is unavailable, an emergency reactor shutdown is the only way to guarantee reactor safety.

[0026] like Figure 1 As shown, the present invention provides a nuclear power plant status feedback processing system, including a turbine bypass system 7 and a reactor protection system 8. The turbine bypass system 7 sends two signals to the reactor protection system 8 respectively, thereby eliminating signal transmission between different series.

[0027] The turbine bypass system 7 comprises a manual isolation valve 1 of A column exhaust valve, a temperature difference processor under pressure mode 2, a control temperature difference signal processor 3, a manual isolation valve 10 of B column exhaust valve, the manual isolation valve 1 of A column exhaust valve and the manual isolation valve 10 of B column exhaust valve output non-full opening signals respectively, the temperature difference processor under pressure mode 2 outputs a temperature difference large signal under pressure mode, the control temperature difference signal processor 3 outputs a control temperature difference signal non-high signal, the manual isolation valve 1 of A column exhaust valve, the temperature difference processor under pressure mode 2 and the control temperature difference signal processor 3 are connected with the first logic or 6 in the reactor protection system 8 through the hardwiring 9, the manual isolation valve 10 of B column exhaust valve, the temperature difference processor under pressure mode 2 and the control temperature difference signal processor 3 are connected with the second logic or 11 in the reactor protection system 8 through the hardwiring 9, the first logic or 6 and the second logic or 11 are realized in the reactor protection system 8, the transmission time of signals between different systems is effectively shortened, and the reactor emergency shutdown caused by signal interaction between A / B columns in the original design logic is avoided, the first logic or 6 can generate an "A column turbine bypass system unavailable" signal, and the second logic or 11 can generate a "B column turbine bypass system unavailable" signal.

[0028] The working principle of the present application is that:

[0029] 1) State feedback signal

[0030] The state signal indicating whether the turbine bypass system of the nuclear power plant is available mainly includes: non-full opening signals of any exhaust valve corresponding manual isolation valve, temperature difference large signal under pressure mode and control temperature difference signal non-high signal. Among them, the exhaust valve is divided into A and B columns, and the non-full opening signals of the corresponding manual isolation valves are the non-full opening signals of the manual isolation valves of A column exhaust valve and the non-full opening signals of the manual isolation valves of B column exhaust valve.

[0031] 2) Turbine bypass system unavailable

[0032] The state signal indicating whether the turbine bypass system is available generated by the turbine bypass system is as described in 1). The above-mentioned signal is transmitted to the reactor protection system in a hardwired manner. In the reactor protection system, the non-full opening signal of the manual isolation valve 1 of A column exhaust valve, the temperature difference large signal under pressure mode and the control temperature difference signal non-high signal are processed by the first logic or 6, to generate an A column turbine bypass system unavailable 4 signal, and the non-full opening signal of the manual isolation valve 10 of B column exhaust valve, the temperature difference large signal under pressure mode and the control temperature difference signal non-high signal are processed by the second logic or 11, to generate a B column turbine bypass system unavailable 11 signal.

[0033] It will be obvious to a person skilled in the art that the application is not limited to the details of the foregoing exemplary embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. The embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims to the identity of the reference signs therein.

[0034] Furthermore, it should be understood that although the description is made on the basis of the embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

Claims

1. A nuclear power plant status feedback processing system, characterized in that, It includes a turbine bypass system (7) and a reactor protection system (8). The turbine bypass system (7) sends two signals to the reactor protection system (8). The reactor protection system (8) is equipped with a first logic OR (6) and a second logic OR (11). The two signals are connected to the first logic OR (6) and the second logic OR (11) respectively. The turbine bypass system (7) includes a manual isolation valve (1) for the A-row discharge valve, a temperature difference processor (2) under pressure mode, a temperature difference control signal processor (3), and a manual isolation valve (10) for the B-row discharge valve. The manual isolation valve (1), the temperature difference processor (2) under pressure mode, and the temperature difference signal processor (3) of the A-row discharge valve constitute the first signal, which is connected to the first logic OR (6) in the reactor protection system (8) through hard wiring (9); The manual isolation valve (10) of the B-row discharge valve, the temperature difference processor (2) under pressure mode, and the control temperature difference signal processor (3) constitute the second signal, which is connected to the second logic OR (11) in the reactor protection system (8) through hard wiring (9).

2. The nuclear power plant status feedback processing system according to claim 1, characterized in that, The manual isolation valve (1) of the discharge valve in column A and the manual isolation valve (10) of the discharge valve in column B output non-fully open signals respectively.

3. The nuclear power plant status feedback processing system according to claim 2, characterized in that, The temperature difference processor (2) under pressure mode outputs a large temperature difference signal under pressure mode.

4. The nuclear power plant status feedback processing system according to claim 3, characterized in that, The control temperature difference signal processor (3) outputs a control temperature difference signal that is not high.

5. The nuclear power plant status feedback processing system according to claim 1, characterized in that, The first logical OR (6) generates an A-column turbine bypass system unavailable signal; the second logical OR (11) generates a B-column turbine bypass system unavailable signal.

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