An operating device and method for the demineralized water system of a nuclear power plant

Abstract

The present invention belongs to the technical field of the demineralized water system of nuclear power plants, and particularly relates to an operating device and method for the demineralized water system of nuclear power plants. The device includes: a pressure switch disposed on the pipeline network of the demineralized water system for sending a signal indicating low pressure in the pipeline network of the demineralized water system; a controller, on which the operating modes of the demineralized water system of the nuclear power plant are set, for obtaining in real time the signal indicating low pressure in the pipeline network of the demineralized water system, selecting the operating mode of the demineralized water system of the nuclear power plant, and performing operating control on the demineralized water system of the nuclear power plant according to the selected operating mode of the demineralized water system of the nuclear power plant; the operating modes of the demineralized water system of the nuclear power plant include an independent operating mode and a combined operating mode. The method is to use the device to perform operating control on the demineralized water system of the nuclear power plant. The present invention reduces the operating energy consumption of the demineralized water system of the nuclear power plant while improving the flexibility and reliability of the operation of the demineralized water system of the nuclear power plant.

Description

Technical Field

[0001] The present invention relates to the technical field of the demineralized water system in nuclear power plants, and particularly to an operating device and method for the demineralized water system in nuclear power plants. Background Art

[0002] The demineralized water system in a nuclear power plant includes two independent first demineralized water systems and second demineralized water systems.

[0003] The first demineralized water system includes a first water tank, a first demineralized water pump, a second demineralized water pump, and a first demineralized water system pipeline network. The inlets of the first demineralized water pump and the second demineralized water pump are respectively connected to the first water tank through pipelines. The outlets of the first demineralized water pump and the second demineralized water pump are respectively connected to the first demineralized water system pipeline network through pipelines. A first stop valve is provided on the pipeline connecting the outlet of the first demineralized water pump to the first demineralized water system pipeline network, and a second stop valve is provided on the pipeline connecting the outlet of the second demineralized water pump to the first demineralized water system pipeline network.

[0004] The second demineralized water system includes a second water tank, a third demineralized water pump, a fourth demineralized water pump, and a second demineralized water system pipeline network. The inlets of the third demineralized water pump and the fourth demineralized water pump are respectively connected to the second water tank through pipelines. The outlets of the third demineralized water pump and the fourth demineralized water pump are respectively connected to the second demineralized water system pipeline network through pipelines. A third stop valve is provided on the pipeline connecting the outlet of the third demineralized water pump to the second demineralized water system pipeline network, and a fourth stop valve is provided on the pipeline connecting the outlet of the fourth demineralized water pump to the second demineralized water system pipeline network.

[0005] The first demineralized water system pipeline network and the second demineralized water system pipeline network are connected through a first isolation valve and a second isolation valve. The first demineralized water system and the second demineralized water system are isolated by the first isolation valve and the second isolation valve, and both the first isolation valve and the second isolation valve are kept in a closed state.

[0006] The two demineralized water systems in the demineralized water system of the nuclear power plant operate independently of each other. The operation logic of each demineralized water system is as follows: two demineralized water pumps are in a one - use - one - standby mode. One demineralized water pump operates to provide the demineralized water flow when there is a water demand in the demineralized water system pipeline network. When the main demineralized water pump stops operating, the standby demineralized water pump is started.

[0007] During the operation of the demineralized water system in the nuclear power plant, the following problems exist:

[0008] 1. One demineralized water pump in each of the two demineralized water systems operates, resulting in a high - energy - consumption problem in the operation of the demineralized water system in the nuclear power plant;

[0009] 2. If both demineralized water pumps in one demineralized water system fail simultaneously, they will be unable to provide demineralized water for the demineralized water system pipeline network of this demineralized water system, resulting in the loss of demineralized water in the demineralized water system pipeline network of this demineralized water system, and thus there is an unreliability problem in the operation of the demineralized water system in the nuclear power plant;

[0010] 3. When the demineralized water tank of a demineralized water system needs to be emptied and repaired, the two demineralized water pumps of the demineralized water system need to be shut down, which will cause the demineralized water system pipeline network of the demineralized water system to lose demineralized water. In order to ensure the supply of demineralized water in the demineralized water system pipeline network of the demineralized water system, it is necessary to manually open the isolation valve between the two demineralized water systems to connect the two demineralized water systems, resulting in the inflexible operation of the demineralized water system in nuclear power plants. Summary of the Invention

[0011] In order to solve the problem that during the operation of the existing demineralized water system in nuclear power plants, one demineralized water pump is operating in each of the two demineralized water systems, resulting in high energy consumption in the operation of the demineralized water system in nuclear power plants, the present invention provides an operating device and method for the demineralized water system in nuclear power plants, which sets independent operation mode and combined operation mode for the demineralized water system in nuclear power plants to choose from; when the demineralized water system in nuclear power plants is in the combined operation mode, only one demineralized water pump is maintained in operation for the two demineralized water systems to achieve energy conservation and consumption reduction.

[0012] In order to solve the problem that during the operation of the existing demineralized water system in nuclear power plants, when two demineralized water pumps in one demineralized water system fail simultaneously, they will be unable to provide demineralized water for the demineralized water system pipeline network of this demineralized water system, resulting in the loss of demineralized water in the demineralized water system pipeline network of this demineralized water system and the unreliable operation of the demineralized water system in nuclear power plants, the present invention provides an operating device and method for the demineralized water system in nuclear power plants, which sets independent operation mode and combined operation mode for the demineralized water system in nuclear power plants to choose from; when the demineralized water system in nuclear power plants is in the combined operation mode, when two demineralized water pumps in one demineralized water system fail simultaneously and are unable to provide demineralized water for the demineralized water system pipeline network of this demineralized water system, another demineralized water system provides demineralized water for the demineralized water system pipeline network of the faulty demineralized water system, without affecting the supply of demineralized water in the demineralized water system pipeline network of the faulty demineralized water system, and improving the reliability of the operation of the demineralized water system in nuclear power plants.

[0013] In order to solve the problem that during the operation of the existing demineralized water system in nuclear power plants, when the demineralized water tank of one demineralized water system needs to be emptied for maintenance, two demineralized water pumps of this demineralized water system need to be shut down. To ensure the supply of demineralized water in the demineralized water system pipeline network of this demineralized water system, it is necessary to manually open the isolation valve between the two demineralized water systems to connect the two demineralized water systems, resulting in the inflexible operation of the demineralized water system in nuclear power plants. The present invention provides an operating device and method for the demineralized water system in nuclear power plants, which sets independent operation mode and combined operation mode for the demineralized water system in nuclear power plants to choose from; when the demineralized water tank of one demineralized water system needs to be emptied for maintenance and the two demineralized water pumps of this demineralized water system need to be shut down and cannot provide demineralized water for the demineralized water system pipeline network of this demineralized water system, select the combined operation mode for the demineralized water system in nuclear power plants. In the combined operation mode, the demineralized water system in nuclear power plants automatically opens the isolation valve between the two demineralized water systems to connect the two demineralized water systems and provide demineralized water for the demineralized water system pipeline network of the demineralized water system being emptied for maintenance; when a large amount of demineralized water leaks due to a pipeline rupture in the pipeline network of one demineralized water system, select the independent operation mode for the demineralized water system in nuclear power plants. In the independent operation mode, the demineralized water system in nuclear power plants automatically closes the isolation valve between the two demineralized water systems to isolate the two demineralized water systems, ensure the supply of demineralized water in the demineralized water system pipeline network of the normally operating demineralized water system, and reduce the leakage of demineralized water in the demineralized water system in nuclear power plants; the operation mode of the demineralized water system in nuclear power plants can be freely selected according to the actual situation, improving the flexibility of the operation of the demineralized water system in nuclear power plants.

[0014] To solve the above technical problems, the present invention provides the following technical solutions:

[0015] An operating device for the demineralized water system in nuclear power plants, comprising:

[0016] A pressure switch arranged on the pipeline network of the first demineralized water system, used to measure the pressure value of the pipeline network of the first demineralized water system in real time, and issue a low-pressure signal for the pipeline network of the first demineralized water system when the pressure value of the pipeline network of the first demineralized water system is lower than the set value;

[0017] A pressure switch arranged on the pipeline network of the second demineralized water system, used to measure the pressure value of the pipeline network of the second demineralized water system in real time, and issue a low-pressure signal for the pipeline network of the second demineralized water system when the pressure value of the pipeline network of the second demineralized water system is lower than the set value;

[0018] A controller, on which the operation mode of the demineralized water system in nuclear power plants is set, used to obtain the low-pressure signal for the pipeline network of the first demineralized water system and the low-pressure signal for the pipeline network of the second demineralized water system in real time; select the operation mode of the demineralized water system in nuclear power plants; and perform operation control on the demineralized water system in nuclear power plants according to the selected operation mode of the demineralized water system in nuclear power plants;

[0019] The operation mode of the demineralized water system in nuclear power plants includes an independent operation mode and a combined operation mode;

[0020] When the demineralized water system of the nuclear power plant is in the independent operation mode, the controller conducts the following operation control on the demineralized water system of the nuclear power plant: close the first isolation valve and the second isolation valve, and operate the two demineralized water systems independently; in each demineralized water system, two demineralized water pumps are in a one-use-one-spare mode, operate the main demineralized water pump, and start the standby demineralized water pump when the main demineralized water pump stops operating or the signal of low pressure in the demineralized water system pipe network is delayed by T1.

[0021] When the demineralized water system of the nuclear power plant is in the combined operation mode, the controller conducts the following operation control on the demineralized water system of the nuclear power plant: open the first isolation valve and the second isolation valve, and operate the two demineralized water systems in combination; in the two demineralized water systems, one demineralized water pump is the main demineralized water pump, and the other three demineralized water pumps are all standby demineralized water pumps, operate the main demineralized water pump; start one standby demineralized water pump with the shortest delay when the signal of low pressure in the demineralized water system pipe network is delayed by T1.

[0022] As one of the realizable ways, when the demineralized water system of the nuclear power plant is in the independent operation mode, the controller obtains the operation status of the main demineralized water pump in each demineralized water system in real time;

[0023] The operation modes of the demineralized water system of the nuclear power plant include the first independent operation mode; the first independent operation mode is: the first demineralized water pump and the third demineralized water pump are both main demineralized water pumps, and the second demineralized water pump and the fourth demineralized water pump are both standby demineralized water pumps;

[0024] When the operation mode of the demineralized water system of the nuclear power plant is selected as the first independent operation mode, the controller conducts the following operation control on the demineralized water system of the nuclear power plant: close the first isolation valve and the second isolation valve to isolate the first demineralized water system and the second demineralized water system; operate the first demineralized water pump and the third demineralized water pump; start the second demineralized water pump when the first demineralized water pump stops operating or the signal of low pressure in the first demineralized water system pipe network is delayed by T1; start the fourth demineralized water pump when the third demineralized water pump stops operating or the signal of low pressure in the second demineralized water system pipe network is delayed by T1.

[0025] As one of the realizable ways, the operation modes of the demineralized water system of the nuclear power plant include the second independent operation mode; the second independent operation mode is: the second demineralized water pump and the fourth demineralized water pump are both main demineralized water pumps, and the first demineralized water pump and the third demineralized water pump are both standby demineralized water pumps;

[0026] When the operation mode of the demineralized water system of the nuclear power plant is selected as the second independent operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: close the first isolation valve and the second isolation valve to isolate the first demineralized water system and the second demineralized water system; operate the second demineralized water pump and the fourth demineralized water pump; when the second demineralized water pump stops operating or the low-pressure signal of the first demineralized water system pipe network is delayed by T1, start the first demineralized water pump; when the fourth demineralized water pump stops operating or the low-pressure signal of the second demineralized water system pipe network is delayed by T1, start the third demineralized water pump.

[0027] As one of the achievable ways, the operation mode of the demineralized water system of the nuclear power plant includes a third independent operation mode; the third independent operation mode is: both the first demineralized water pump and the fourth demineralized water pump are main demineralized water pumps, and both the second demineralized water pump and the third demineralized water pump are standby demineralized water pumps;

[0028] When the operation mode of the demineralized water system of the nuclear power plant is selected as the third independent operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: close the first isolation valve and the second isolation valve to isolate the first demineralized water system and the second demineralized water system; operate the first demineralized water pump and the fourth demineralized water pump; when the first demineralized water pump stops operating or the low-pressure signal of the first demineralized water system pipe network is delayed by T1, start the second demineralized water pump; when the fourth demineralized water pump stops operating or the low-pressure signal of the second demineralized water system pipe network is delayed by T1, start the third demineralized water pump.

[0029] As one of the achievable ways, the operation mode of the demineralized water system of the nuclear power plant includes a fourth independent operation mode; the fourth independent operation mode is: both the second demineralized water pump and the third demineralized water pump are main demineralized water pumps, and both the first demineralized water pump and the fourth demineralized water pump are standby demineralized water pumps;

[0030] When the operation mode of the demineralized water system of the nuclear power plant is selected as the fourth independent operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: close the first isolation valve and the second isolation valve to isolate the first demineralized water system and the second demineralized water system; operate the second demineralized water pump and the third demineralized water pump; when the second demineralized water pump stops operating or the low-pressure signal of the first demineralized water system pipe network is delayed by T1, start the first demineralized water pump; when the third demineralized water pump stops operating or the low-pressure signal of the second demineralized water system pipe network is delayed by T1, start the fourth demineralized water pump.

[0031] As one of the achievable ways, the operation mode of the demineralized water system of the nuclear power plant includes a first combined operation mode; the first combined operation mode is: the first demineralized water pump is the main demineralized water pump, and the second demineralized water pump, the third demineralized water pump and the fourth demineralized water pump are all standby demineralized water pumps;

[0032] When the operating mode of the demineralized water system of the nuclear power plant is selected as the first combined operating mode, the controller performs the following operating controls on the demineralized water system of the nuclear power plant: Open the first isolation valve and the second isolation valve to connect the first demineralized water system and the second demineralized water system as a whole; Operate the first demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T1 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T1, start the third demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T2 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T2, if it is determined that the third demineralized water pump cannot be started, start the second demineralized water pump or the fourth demineralized water pump.

[0033] As one of the achievable ways, the operating modes of the demineralized water system of the nuclear power plant include the second combined operating mode; The second combined operating mode is: The second demineralized water pump is the main demineralized water pump, and the first demineralized water pump, the third demineralized water pump and the fourth demineralized water pump are all standby demineralized water pumps;

[0034] When the operating mode of the demineralized water system of the nuclear power plant is selected as the second combined operating mode, the controller performs the following operating controls on the demineralized water system of the nuclear power plant: Open the first isolation valve and the second isolation valve to connect the first demineralized water system and the second demineralized water system as a whole; Operate the second demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T1 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T1, start the first demineralized water pump or the third demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T2 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T2, if it is determined that both the first demineralized water pump and the third demineralized water pump cannot be started, start the fourth demineralized water pump.

[0035] As one of the achievable ways, the operating modes of the demineralized water system of the nuclear power plant include the third combined operating mode; The third combined operating mode is: The third demineralized water pump is the main demineralized water pump, and the first demineralized water pump, the second demineralized water pump and the fourth demineralized water pump are all standby demineralized water pumps;

[0036] When the operating mode of the demineralized water system of the nuclear power plant is selected as the third combined operating mode, the controller performs the following operating controls on the demineralized water system of the nuclear power plant: Open the first isolation valve and the second isolation valve to connect the first demineralized water system and the second demineralized water system as a whole; Operate the third demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T1 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T1, start the first demineralized water pump; When the low-pressure signal of the first demineralized water system pipeline network is delayed by T2 or the low-pressure signal of the second demineralized water system pipeline network is delayed by T2, if it is determined that the first demineralized water pump cannot be started, start the second demineralized water pump or the fourth demineralized water pump.

[0037] As one of the realizable ways, the operation modes of the demineralized water system of a nuclear power plant include a fourth combined operation mode; the fourth combined operation mode is that the fourth demineralized water pump is the main demineralized water pump, and the first, second, and third demineralized water pumps are all standby demineralized water pumps;

[0038] When the operation mode of the demineralized water system of the nuclear power plant is selected as the fourth combined operation mode, the controller conducts the following operation control on the demineralized water system of the nuclear power plant: open the first isolation valve and the second isolation valve to connect the first demineralized water system and the second demineralized water system as a whole; operate the fourth demineralized water pump; when the low-pressure signal of the first demineralized water system pipe network is delayed by T1 or the low-pressure signal of the second demineralized water system pipe network is delayed by T1, start the first demineralized water pump or the third demineralized water pump; when the low-pressure signal of the first demineralized water system pipe network is delayed by T2 or the low-pressure signal of the second demineralized water system pipe network is delayed by T2, determine that both the first demineralized water pump and the third demineralized water pump cannot be started, and start the second demineralized water pump.

[0039] As one of the realizable ways, the low-pressure set value of the demineralized water system pipe network is lower than the normal pressure value (0.1 - 0.2) MPa; T1 is greater than the normal pressure fluctuation time of the demineralized water system pipe network by (1 - 9) s; T2 = T1 + the time required to re-establish the pressure of the demineralized water system pipe network after the standby demineralized water pump is started + (2 - 3) s.

[0040] The present invention also provides a method for operating a demineralized water system of a nuclear power plant, which uses the above-mentioned device for operating a demineralized water system of a nuclear power plant, and includes the following steps:

[0041] Step 1: Select the operation mode of the demineralized water system of the nuclear power plant on the controller;

[0042] Step 2: The controller conducts operation control on the demineralized water system of the nuclear power plant according to the selected operation mode of the demineralized water system of the nuclear power plant.

[0043] The beneficial technical effects of the present invention:

[0044] For the device and method for operating a demineralized water system of a nuclear power plant of the present invention, the operation modes of the demineralized water system of the nuclear power plant include a single operation mode and a combined operation mode for selection, and the operation mode of the demineralized water system of the nuclear power plant can be freely selected according to the actual situation, improving the operation flexibility of the demineralized water system of the nuclear power plant; when the demineralized water system of the nuclear power plant is in the combined operation mode, only one demineralized water pump is maintained for operation by using two demineralized water systems, achieving energy conservation and consumption reduction; when the demineralized water system of the nuclear power plant is in the combined operation mode, there is one main demineralized water pump and three standby demineralized water pumps, ensuring the supply of demineralized water for the demineralized water system pipe network of the two demineralized water systems, and improving the operation reliability of the demineralized water system of the nuclear power plant; it is applicable to the demineralized water system of the conventional island and the nuclear island of the nuclear power plant, and is also applicable to the demineralized water system of the thermal power plant. Description of the Drawings

[0045] Figure 1 This is a schematic structural diagram of an embodiment of the operating device of the demineralized water system in a nuclear power plant according to the present invention.

[0046] In the figure, 1 is the first demineralized water system; 2 is the second demineralized water system; 3 is the first isolation valve; 4 is the second isolation valve; 11 is the first demineralized water tank; 12 is the first demineralized water pump; 13 is the second demineralized water pump; 14 is the pipe network of the first demineralized water system; 15 is the first stop valve; 16 is the second stop valve; 17 is the first pressure switch; 18 is the second pressure switch; 21 is the second demineralized water tank; 22 is the third demineralized water pump; 23 is the fourth demineralized water pump; 24 is the pipe network of the second demineralized water system; 25 is the third stop valve; 26 is the fourth stop valve; 27 is the third pressure switch; 28 is the fourth pressure switch. Detailed implementation manners

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "provided with" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", "third", "fourth", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0048] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0049] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and specific embodiments.

[0050] The demineralized water system of a nuclear power plant includes two independent first demineralized water systems 1 and second demineralized water systems 2;

[0051] The first demineralized water system 1 includes a first water tank 11, a first demineralized water pump 12, a second demineralized water pump 13, and a first demineralized water system pipe network 14. The inlets of the first demineralized water pump 12 and the second demineralized water pump 13 are respectively connected to the first water tank 11 through pipes. The outlets of the first demineralized water pump 12 and the second demineralized water pump 13 are respectively connected to the first demineralized water system pipe network 14 through pipes. A first stop valve 15 is provided on the pipe connecting the outlet of the first demineralized water pump 12 to the first demineralized water system pipe network 14, and a second stop valve 16 is provided on the pipe connecting the outlet of the second demineralized water pump 13 to the first demineralized water system pipe network 14;

[0052] The second demineralized water system 2 includes a second water tank 21, a third demineralized water pump 22, a fourth demineralized water pump 23, and a second demineralized water system pipe network 24. The inlets of the third demineralized water pump 22 and the fourth demineralized water pump 23 are respectively connected to the second water tank 21 through pipes. The outlets of the third demineralized water pump 22 and the fourth demineralized water pump 23 are respectively connected to the second demineralized water system pipe network 24 through pipes. A third stop valve 25 is provided on the pipe connecting the outlet of the third demineralized water pump 22 to the second demineralized water system pipe network 24, and a fourth stop valve 26 is provided on the pipe connecting the outlet of the fourth demineralized water pump 23 to the second demineralized water system pipe network 24;

[0053] The first demineralized water system pipe network 14 and the second demineralized water system pipe network 24 are connected through a first isolation valve 3 and a second isolation valve 4 by pipes.

[0054] This embodiment provides an operating device for the demineralized water system of a nuclear power plant, including:

[0055] Mutually redundant first pressure switch 17 and second pressure switch 18, which are arranged on the first demineralized water system pipe network 14, are used to measure the pressure value of the first demineralized water system pipe network 14 in real time, and send out a low pressure signal of the first demineralized water system pipe network 14 when the pressure value of the first demineralized water system pipe network 14 is lower than the set value;

[0056] Mutually redundant third pressure switch 27 and fourth pressure switch 28, which are arranged on the second demineralized water system pipe network 24, are used to measure the pressure value of the second demineralized water system pipe network 24 in real time, and send out a low pressure signal of the second demineralized water system pipe network 24 when the pressure value of the second demineralized water system pipe network 24 is lower than the set value;

[0057] A controller, on which the operating mode of the demineralized water system of the nuclear power plant is set, is used to obtain in real time the low pressure signal of the first demineralized water system pipe network 14 sent by the first pressure switch 17 and the second pressure switch 18, and the low pressure signal of the second demineralized water system pipe network 24 sent by the third pressure switch 27 and the fourth pressure switch 28; select the operating mode of the demineralized water system of the nuclear power plant; and perform operating control on the demineralized water system of the nuclear power plant according to the selected operating mode of the demineralized water system of the nuclear power plant;

[0058] The operation modes of the demineralized water system in a nuclear power plant include an independent operation mode and a combined operation mode;

[0059] In the independent operation mode of the demineralized water system in a nuclear power plant, the controller conducts the following operation control on the demineralized water system in the nuclear power plant: close the first isolation valve 3 and the second isolation valve 4, and operate the two demineralized water systems independently; in each demineralized water system, two demineralized water pumps are in a one - use - one - standby mode, operate the main demineralized water pump, and start the standby demineralized water pump when the main demineralized water pump stops operating or the low - pressure signal of the demineralized water system pipe network is delayed for T1.

[0060] In the combined operation mode of the demineralized water system in a nuclear power plant, the controller conducts the following operation control on the demineralized water system in the nuclear power plant: open the first isolation valve 3 and the second isolation valve 4, and operate the two demineralized water systems in combination; in the two demineralized water systems, one demineralized water pump is the main demineralized water pump, and the other three demineralized water pumps are all standby demineralized water pumps, operate the main demineralized water pump; when the low - pressure signal of the demineralized water system pipe network is delayed for T1, start one standby demineralized water pump with the shortest delay.

[0061] In order to achieve the operation mode where only one demineralized water pump operates in the two demineralized water systems, it is necessary to transmit the operation status of the two demineralized water pumps in the first demineralized water system 1 to the second demineralized water system 2, or transmit the operation status of the two demineralized water pumps in the second demineralized water system 2 to the first demineralized water system 1. However, the two demineralized water systems are relatively far apart, and arranging signal transmission lines is required for signal transmission, which is difficult in construction and has a relatively high transformation cost.

[0062] In the present invention, two mutually redundant pressure switches are provided on both the pipe network 14 of the first demineralized water system and the pipe network 24 of the second demineralized water system; when the main demineralized water pump stops operating, the pressure switch on the demineralized water system pipe network will send out a low - pressure signal; the controller obtains the low - pressure signal sent by the pressure switch in real time, determines that the main demineralized water pump has stopped operating based on the low - pressure signal sent by the pressure switch, and thus starts the standby demineralized water pump to maintain the pressure of the demineralized water system pipe network.

[0063] In the combined operation mode of the demineralized water system in a nuclear power plant, when the main demineralized water pump stops operating, it will cause all three standby demineralized water pumps to start up in standby mode. In the present invention, different delays are set for the standby demineralized water pumps. The standby demineralized water pump with a shorter delay starts first. When the standby demineralized water pump with a shorter delay cannot start, then start the standby demineralized water pump with a longer delay to avoid the simultaneous start of the standby demineralized water pumps.

[0064] In this embodiment, as one of the achievable ways, in the independent operation mode of the demineralized water system in a nuclear power plant, the controller obtains the operation status of the main demineralized water pump in each demineralized water system in real time;

[0065] The operation modes of the demineralized water system in a nuclear power plant include a first independent operation mode; the first independent operation mode is that the first demineralized water pump 12 and the third demineralized water pump 22 are both main demineralized water pumps, and the second demineralized water pump 13 and the fourth demineralized water pump 23 are both standby demineralized water pumps;

[0066] When the operation mode of the demineralized water system in a nuclear power plant is selected as the first independent operation mode, the controller performs the following operation control on the demineralized water system in the nuclear power plant: close the first isolation valve 3 and the second isolation valve 4 to isolate the first demineralized water system 1 and the second demineralized water system 2; operate the first demineralized water pump 12 and the third demineralized water pump 22; when the first demineralized water pump 12 stops operating or the pressure low signal of the first demineralized water system pipe network 14 is delayed by T1, start the second demineralized water pump 13; when the third demineralized water pump 22 stops operating or the pressure low signal of the second demineralized water system pipe network 24 is delayed by T1, start the fourth demineralized water pump 23.

[0067] In this embodiment, as one of the realizable ways, the operation modes of the demineralized water system in a nuclear power plant include a second independent operation mode; the second independent operation mode is that the second demineralized water pump 13 and the fourth demineralized water pump 23 are both main demineralized water pumps, and the first demineralized water pump 12 and the third demineralized water pump 22 are both standby demineralized water pumps;

[0068] When the operation mode of the demineralized water system in a nuclear power plant is selected as the second independent operation mode, the controller performs the following operation control on the demineralized water system in the nuclear power plant: close the first isolation valve 3 and the second isolation valve 4 to isolate the first demineralized water system 1 and the second demineralized water system 2; operate the second demineralized water pump 13 and the fourth demineralized water pump 23; when the second demineralized water pump 13 stops operating or the pressure low signal of the first demineralized water system pipe network 14 is delayed by T1, start the first demineralized water pump 12; when the fourth demineralized water pump 23 stops operating or the pressure low signal of the second demineralized water system pipe network 24 is delayed by T1, start the third demineralized water pump 22.

[0069] In this embodiment, as one of the realizable ways, the operation modes of the demineralized water system in a nuclear power plant include a third independent operation mode; the third independent operation mode is that the first demineralized water pump 12 and the fourth demineralized water pump 23 are both main demineralized water pumps, and the second demineralized water pump 13 and the third demineralized water pump 22 are both standby demineralized water pumps;

[0070] When the operating mode of the demineralized water system of the nuclear power plant is selected as the third independent operating mode, the controller conducts the following operating control on the demineralized water system of the nuclear power plant: close the first isolation valve 3 and the second isolation valve 4 to isolate the first demineralized water system 1 and the second demineralized water system 2; operate the first demineralization water pump 12 and the fourth demineralization water pump 23; when the first demineralization water pump 12 stops operating or the low-pressure signal of the pipeline network 14 of the first demineralized water system is delayed by T1, start the second demineralization water pump 13; when the fourth demineralization water pump 23 stops operating or the low-pressure signal of the pipeline network 24 of the second demineralized water system is delayed by T1, start the third demineralization water pump 22.

[0071] In this embodiment, as one of the realizable ways, the operating mode of the demineralized water system of the nuclear power plant includes a fourth independent operating mode; the fourth independent operating mode is: both the second demineralization water pump 13 and the third demineralization water pump 22 are main demineralization water pumps, and both the first demineralization water pump 12 and the fourth demineralization water pump 23 are standby demineralization water pumps;

[0072] When the operating mode of the demineralized water system of the nuclear power plant is selected as the fourth independent operating mode, the controller conducts the following operating control on the demineralized water system of the nuclear power plant: close the first isolation valve 3 and the second isolation valve 4 to isolate the first demineralized water system 1 and the second demineralized water system 2; operate the second demineralization water pump 13 and the third demineralization water pump 22; when the second demineralization water pump 13 stops operating or the low-pressure signal of the pipeline network 14 of the first demineralized water system is delayed by T1, start the first demineralization water pump 12; when the third demineralization water pump 22 stops operating or the low-pressure signal of the pipeline network 24 of the second demineralized water system is delayed by T1, start the fourth demineralization water pump 23.

[0073] In this embodiment, as one of the realizable ways, the operating mode of the demineralized water system of the nuclear power plant includes a first combined operating mode; the first combined operating mode is: the first demineralization water pump 12 is the main demineralization water pump, and the second demineralization water pump 13, the third demineralization water pump 22, and the fourth demineralization water pump 23 are all standby demineralization water pumps;

[0074] When the operating mode of the demineralized water system of the nuclear power plant is selected as the first combined operating mode, the controller conducts the following operating control on the demineralized water system of the nuclear power plant: open the first isolation valve 3 and the second isolation valve 4 to connect the first demineralized water system 1 and the second demineralized water system 2 as a whole; operate the first demineralization water pump 12; when the low-pressure signal of the pipeline network 14 of the first demineralized water system is delayed by T1 or the low-pressure signal of the pipeline network 24 of the second demineralized water system is delayed by T1, start the third demineralization water pump 22; when the low-pressure signal of the pipeline network 14 of the first demineralized water system is delayed by T2 or the low-pressure signal of the pipeline network 24 of the second demineralized water system is delayed by T2, determine that the third demineralization water pump 22 cannot be started, and start the second demineralization water pump 13 or the fourth demineralization water pump 23.

[0075] In this embodiment, as one of the realizable ways, the operation modes of the demineralized water system of the nuclear power plant include a second combined operation mode; the second combined operation mode is that the second demineralized water pump 13 is the main demineralized water pump, and the first demineralized water pump 12, the third demineralized water pump 22, and the fourth demineralized water pump 23 are all standby demineralized water pumps;

[0076] When the operation mode of the demineralized water system of the nuclear power plant is selected as the second combined operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: open the first isolation valve 3 and the second isolation valve 4 to connect the first demineralized water system 1 and the second demineralized water system 2 as a whole; operate the second demineralized water pump 13; when the low pressure signal of the first demineralized water system pipe network 14 is delayed by T1 or the low pressure signal of the second demineralized water system pipe network 24 is delayed by T1, start the first demineralized water pump 12 or the third demineralized water pump 22; when the low pressure signal of the first demineralized water system pipe network 14 is delayed by T2 or the low pressure signal of the second demineralized water system pipe network 24 is delayed by T2, determine that both the first demineralized water pump 12 and the third demineralized water pump 22 cannot be started, and start the fourth demineralized water pump 23.

[0077] In this embodiment, as one of the realizable ways, the operation modes of the demineralized water system of the nuclear power plant include a third combined operation mode; the third combined operation mode is that the third demineralized water pump 22 is the main demineralized water pump, and the first demineralized water pump 12, the second demineralized water pump 13, and the fourth demineralized water pump 23 are all standby demineralized water pumps;

[0078] When the operation mode of the demineralized water system of the nuclear power plant is selected as the third combined operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: open the first isolation valve 3 and the second isolation valve 4 to connect the first demineralized water system 1 and the second demineralized water system 2 as a whole; operate the third demineralized water pump 22; when the low pressure signal of the first demineralized water system pipe network 14 is delayed by T1 or the low pressure signal of the second demineralized water system pipe network 24 is delayed by T1, start the first demineralized water pump 12; when the low pressure signal of the first demineralized water system pipe network 14 is delayed by T2 or the low pressure signal of the second demineralized water system pipe network 24 is delayed by T2, determine that the first demineralized water pump 12 cannot be started, and start the second demineralized water pump 13 or the fourth demineralized water pump 23.

[0079] In this embodiment, as one of the realizable ways, the operation modes of the demineralized water system of the nuclear power plant include a fourth combined operation mode; the fourth combined operation mode is that the fourth demineralized water pump 23 is the main demineralized water pump, and the first demineralized water pump 12, the second demineralized water pump 13, and the third demineralized water pump 22 are all standby demineralized water pumps;

[0080] When the operation mode of the demineralized water system of the nuclear power plant is selected as the fourth combined operation mode, the controller performs the following operation control on the demineralized water system of the nuclear power plant: Open the first isolation valve 3 and the second isolation valve 4 to connect the first demineralized water system 1 and the second demineralized water system 2 as a whole; Operate the fourth demineralized water pump 23; When the low-pressure signal of the first demineralized water system pipe network 14 is delayed by T1 or the low-pressure signal of the second demineralized water system pipe network 24 is delayed by T1, start the first demineralized water pump 12 or the third demineralized water pump 22; When the low-pressure signal of the first demineralized water system pipe network 14 is delayed by T2 or the low-pressure signal of the second demineralized water system pipe network 24 is delayed by T2, it is determined that both the first demineralized water pump 12 and the third demineralized water pump 22 cannot be started, and start the second demineralized water pump 13.

[0081] In this embodiment, as one of the achievable ways, the normal pressure of the demineralized water system pipe network is 0.5 MPa. Therefore, the low-pressure set values of both the first demineralized water system pipe network 14 and the second demineralized water system pipe network 24 are set to 0.4 MPa, and can be adjusted between (0.3 - 0.4) MPa according to the actual situation.

[0082] In this embodiment, as one of the achievable ways, during the operation of the main demineralized water pump, the pressure of the demineralized water system pipe network may fluctuate due to factors such as changes in water consumption. The fluctuation time is generally between (1 - 3) s and then returns to 0.5 MPa. Therefore, T1 is set to 5 s and can be adjusted between (4 - 10) s according to the actual situation to avoid the standby start of the standby demineralized water pump due to normal pressure fluctuations.

[0083] In this embodiment, as one of the achievable ways, after the main demineralized water pump is shut down, it takes (2 - 3) s for the standby demineralized water pump to re-establish the pressure of the demineralized water system pipe network after starting. Therefore, T2 = T1 + 5S; T2 is 10 s and can be adjusted between (8 - 16) s according to the actual situation to avoid misjudgment of the inability to start the standby demineralized water pump.

[0084] Those skilled in the art can also set that both the first demineralized water pump 12 and the third demineralized water pump 22 as standby demineralized water pumps are delayed by T2 for standby start, and both the second demineralized water pump 13 and the fourth demineralized water pump 23 as standby demineralized water pumps are delayed by T1 for standby start. The standby start logic is similar to that of this embodiment and will not be elaborated here.

[0085] This embodiment also provides a method for operating the demineralized water system of a nuclear power plant, using the above-mentioned device for operating the demineralized water system of a nuclear power plant, including the following steps:

[0086] Step 1: Select the operation mode of the demineralized water system of the nuclear power plant on the controller;

[0087] Step 2: The controller performs operation control on the demineralized water system of the nuclear power plant according to the selected operation mode of the demineralized water system of the nuclear power plant.

[0088] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent for the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several variations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention shall be subject to the appended claims.

Claims

1. A desalted water system operating device for a nuclear power plant, characterized in that: include: A pressure switch disposed on the first desalted water system pipe network (14), used to measure the pressure value of the first desalted water system pipe network (14) in real time, and to send a first desalted water system pipe network (14) low pressure signal when the pressure value of the first desalted water system pipe network (14) is lower than a set value; A pressure switch disposed on the second desalted water system pipe network (24), used to measure the pressure value of the second desalted water system pipe network (24) in real time, and to send a second desalted water system pipe network (24) low pressure signal when the pressure value of the second desalted water system pipe network (24) is lower than a set value; a controller having an operation mode of a desalted water system of a nuclear power plant, and used for obtaining in real time a low pressure signal of a first desalted water system pipe network (14) and a low pressure signal of a second desalted water system pipe network (24); selecting an operation mode of the desalted water system of the nuclear power plant; and controlling the operation of the desalted water system of the nuclear power plant according to the selected operation mode of the desalted water system of the nuclear power plant; The operation modes of the desalinated water system of a nuclear power plant include independent operation mode and joint operation mode; When the desalting water system of a nuclear power plant is in an independent operation mode, the controller controls the operation of the desalting water system of the nuclear power plant as follows: the first isolation valve (3) and the second isolation valve (4) are closed, and the two desalting water systems are operated independently; in each desalting water system, two desalting water pumps are used as one for use and one for backup, and the main desalting water pump is operated, and the main desalting water pump is stopped, or the first desalting water system pipe network (14) or the second desalting water system pipe network (24) has a low pressure signal delay T1, and the backup desalting water pump is started; When the desalting water system of a nuclear power plant is in a joint operation mode, the controller controls the operation of the desalting water system of the nuclear power plant as follows: the first isolation valve (3) and the second isolation valve (4) are opened to jointly operate the two desalting water systems; in the two desalting water systems, one desalting water pump is a main desalting water pump, and the other three desalting water pumps are standby desalting water pumps, and the main desalting water pump is operated; when the pressure delay of the first desalting water system pipe network (14) or the second desalting water system pipe network (24) is T1, a standby desalting water pump with the shortest delay is started; when the pressure delay of the first desalting water system pipe network (14) or the second desalting water system pipe network (24) is T2, it is determined that the standby desalting water pump with the shortest delay cannot be started; The first desalted water system pipe network (14) and the second desalted water system pipe network (24) are connected via a first isolation valve (3) and a second isolation valve (4) pipe.

2. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of a nuclear power plant includes a first independent operation mode; the first independent operation mode is: the first desalted water pump (12) and the third desalted water pump (22) are both main desalted water pumps, and the second desalted water pump (13) and the fourth desalted water pump (23) are both standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the first independent operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: closes the first isolation valve (3) and the second isolation valve (4) to isolate the first desalted water system (1) from the second desalted water system (2); operates the first desalted water pump (12) and the third desalted water pump (22); when the first desalted water pump (12) stops operating or the pressure signal of the first desalted water system pipe network (14) is delayed by T1, the second desalted water pump (13) is started; when the third desalted water pump (22) stops operating or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, the fourth desalted water pump (23) is started; T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) seconds; and the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

3. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of a nuclear power plant includes a second independent operation mode; the second independent operation mode is: the second desalted water pump (13) and the fourth desalted water pump (23) are both main desalted water pumps, and the first desalted water pump (12) and the third desalted water pump (22) are both standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the second independent operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: close the first isolation valve (3) and the second isolation valve (4) to isolate the first desalted water system (1) and the second desalted water system (2); operate the second desalted water pump (13) and the fourth desalted water pump (23); when the second desalted water pump (13) stops operating or the pressure signal of the first desalted water system pipe network (14) is delayed by T1, start the first desalted water pump (12); when the fourth desalted water pump (23) stops operating or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, start the third desalted water pump (22); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) seconds; and the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

4. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of the nuclear power plant includes a third independent operation mode; the third independent operation mode is: the first desalted water pump (12) and the fourth desalted water pump (23) are both main desalted water pumps, and the second desalted water pump (13) and the third desalted water pump (22) are both standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the third independent operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: closes the first isolation valve (3) and the second isolation valve (4) to isolate the first desalted water system (1) from the second desalted water system (2); operates the first desalted water pump (12) and the fourth desalted water pump (23); when the first desalted water pump (12) stops operating or the pressure signal of the first desalted water system pipe network (14) is delayed by T1, the second desalted water pump (13) is started; when the fourth desalted water pump (23) stops operating or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, the third desalted water pump (22) is started; T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) seconds; and the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

5. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of a nuclear power plant includes a fourth independent operation mode; the fourth independent operation mode is: the second desalted water pump (13) and the third desalted water pump (22) are both main desalted water pumps, and the first desalted water pump (12) and the fourth desalted water pump (23) are both standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the fourth independent operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: close the first isolation valve (3) and the second isolation valve (4) to isolate the first desalted water system (1) from the second desalted water system (2); operate the second desalted water pump (13) and the third desalted water pump (22); when the second desalted water pump (13) stops operating or the pressure signal of the first desalted water system pipe network (14) is delayed by T1, start the first desalted water pump (12); when the third desalted water pump (22) stops operating or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, start the fourth desalted water pump (23); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) seconds; and the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

6. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of a nuclear power plant includes a first combined operation mode; the first combined operation mode is: the first desalted water pump (12) is a main desalted water pump, and the second desalted water pump (13), the third desalted water pump (22) and the fourth desalted water pump (23) are all standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the first combined operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: opening the first isolation valve (3) and the second isolation valve (4) to connect the first desalted water system (1) and the second desalted water system (2) into a whole; operating the first desalted water pump (12); when the pressure signal of the first desalted water system pipe network (14) is delayed by T1 or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, starting the third desalted water pump (22); when the pressure signal of the first desalted water system pipe network (14) is delayed by T2 or the pressure signal of the second desalted water system pipe network (24) is delayed by T2, determining that the third desalted water pump (22) cannot be started, and starting the second desalted water pump (13) or the fourth desalted water pump (23); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) s; T2 = T1 + the time required to re-establish the pressure of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) after the standby desalted water pump is started + (2 to 3) s; the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

7. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of the nuclear power plant includes a second joint operation mode; the second joint operation mode is: the second desalted water pump (13) is a main desalted water pump, and the first desalted water pump (12), the third desalted water pump (22) and the fourth desalted water pump (23) are all standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the second combined operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: opening the first isolation valve (3) and the second isolation valve (4) to connect the first desalted water system (1) and the second desalted water system (2) into a whole; operating the second desalted water pump (13); when the pressure signal of the first desalted water system pipe network (14) is delayed by T1 or the pressure signal of the second desalted water system pipe network (24) is delayed by T1, starting the first desalted water pump (12) or the third desalted water pump (22); when the pressure signal of the first desalted water system pipe network (14) is delayed by T2 or the pressure signal of the second desalted water system pipe network (24) is delayed by T2, determining that both the first desalted water pump (12) and the third desalted water pump (22) cannot be started, and starting the fourth desalted water pump (23); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) s; T2 = T1 + the time required to re-establish the pressure of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) after the standby desalted water pump is started + (2 to 3) s; the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

8. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of the nuclear power plant includes a third joint operation mode; the third joint operation mode is: the third desalted water pump (22) is a main desalted water pump, and the first desalted water pump (12), the second desalted water pump (13) and the fourth desalted water pump (23) are all standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the third combined operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: opening the first isolation valve (3) and the second isolation valve (4) to connect the first desalted water system (1) and the second desalted water system (2) into a whole; operating the third desalted water pump (22); starting the first desalted water pump (12) when the pressure signal of the first desalted water system pipe network (14) is delayed by T1 or the pressure signal of the second desalted water system pipe network (24) is delayed by T1; determining that the first desalted water pump (12) cannot be started when the pressure signal of the first desalted water system pipe network (14) is delayed by T2 or the pressure signal of the second desalted water system pipe network (24) is delayed by T2, starting the second desalted water pump (13) or the fourth desalted water pump (23); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) s; T2 = T1 + the time required to re-establish the pressure of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) after the standby desalted water pump is started + (2 to 3) s; the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

9. The desalted water system operating device for a nuclear power plant according to claim 1, characterized in that: The operation mode of the desalted water system of the nuclear power plant includes a fourth joint operation mode; the fourth joint operation mode is: the fourth desalted water pump (23) is a main desalted water pump, and the first desalted water pump (12), the second desalted water pump (13) and the third desalted water pump (22) are all standby desalted water pumps; When the operation mode of the desalted water system of the nuclear power plant is selected as the fourth combined operation mode, the controller performs the following operation control on the desalted water system of the nuclear power plant: opening the first isolation valve (3) and the second isolation valve (4) to connect the first desalted water system (1) and the second desalted water system (2) into a whole; operating the fourth desalted water pump (23); starting the first desalted water pump (12) or the third desalted water pump (22) when the pressure signal of the first desalted water system pipe network (14) is delayed by T1 or the pressure signal of the second desalted water system pipe network (24) is delayed by T1; when the pressure signal of the first desalted water system pipe network (14) is delayed by T2 or the pressure signal of the second desalted water system pipe network (24) is delayed by T2, it is determined that both the first desalted water pump (12) and the third desalted water pump (22) cannot be started, and starting the second desalted water pump (13); T1 is greater than the normal pressure fluctuation time of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) by (1 to 9) s; T2 = T1 + the time required to re-establish the pressure of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) after the standby desalted water pump is started + (2 to 3) s; the low pressure setting value of the first desalted water system pipe network (14) or the second desalted water system pipe network (24) is lower than the normal pressure value by (0.1 to 0.2) MPa.

10. A method for operating a desalted water system in a nuclear power plant, characterized in that: The desalted water system operating device for a nuclear power plant according to any one of claims 1 to 9 comprises the following steps: Step 1: Select the operation mode of the desalted water system of the nuclear power plant on the controller; Step 2: The controller controls the operation of the desalted water system of the nuclear power plant according to the selected operation mode of the desalted water system of the nuclear power plant.

Images