A nuclear power plant secondary emergency cooling water (SEN) system

Abstract

The application discloses a nuclear power plant auxiliary cooling water SEN system and relates to the field of cooling water of a nuclear power plant, and improves the SEN system in the prior art in order to save energy, stops third booster pumps, fourth booster pumps, three SRI orifices and three CVI orifices and other flow components, thereby reducing the resistance of seawater flow, and achieving "non-active" water replenishment, that is, sufficient seawater can be provided to SRI heat exchangers and CVI coolers even if the first booster pump and the second booster pump are both in a non-working state.

Description

Technical Field

[0001] This application relates to the field of cooling water technology for nuclear power plants, and more particularly to a nuclear power plant auxiliary cooling water SEN system. Background Technology

[0002] The SEN (Supplementary Emergency Cooling Water System) system includes: booster pumps, automatic cleaning filters, bypass filters, SRI (System Reliability Institute) coolers, and CVI (Condenser Vacuum System) coolers. The CRF (Central Circulating Water System) is used to pump seawater to the SEN system; the booster pumps provide pressure to ensure seawater flows through the automatic cleaning filters and bypass filters to the SRI heat exchangers and CVI coolers, thereby cooling them.

[0003] In the process of realizing this invention, the applicant discovered that if the above-mentioned SEN system is applied to areas with high seawater temperature, a large amount of seawater is required in the process of cooling the SRI heat exchanger and CVI cooler; if the above-mentioned SEN system is applied to areas with low seawater temperature, the flow rate of seawater supplied by the SEN system will be much greater than the flow rate required by the SRI heat exchanger and CVI cooler, resulting in energy waste. Summary of the Invention

[0004] In view of the above problems, this application provides a nuclear power plant auxiliary cooling water SEN system to reduce the energy consumption of the SEN system while meeting the seawater flow requirements of the SRI heat exchanger and CVI cooler. The specific solution is as follows:

[0005] The first aspect of this application provides a nuclear power plant auxiliary cooling water SEN system, comprising:

[0006] The SEN system is applied in areas where the seawater temperature is below a preset temperature threshold. The SEN system includes: a first check valve, a first electrically operated isolation valve, a first booster pump, a second check valve, a second electrically operated isolation valve, a third check valve, a third electrically operated isolation valve, a second booster pump, a fourth check valve, a fourth electrically operated isolation valve, a fifth electrically operated isolation valve, an automatic cleaning filter, a sixth electrically operated isolation valve, a seventh electrically operated isolation valve, a bypass filter, an eighth electrically operated isolation valve, a heat exchanger bypass flow regulating valve, three sets of SRI water temperature control regulating valves, three sets of SRI heat exchangers, and three sets of CVI coolers. The three sets of SRI water temperature control regulating valves include a first SRI water temperature control regulating valve, a second SRI water temperature control regulating valve, and a third SRI water temperature control regulating valve. The three sets of CVI coolers include a first CVI cooler, a second CVI cooler, and a third CVI cooler. The three sets of SRI heat exchangers include a first SRI heat exchanger, a second SRI heat exchanger, and a third SRI heat exchanger.

[0007] The first check valve and the first booster pump are both connected to the upstream pipeline of the condenser at the outlet of the first CRF pump. The first check valve is connected to the first electric isolation valve, and the first booster pump is connected to the second electric isolation valve via the second check valve. The third check valve and the second booster pump are both connected to the upstream pipeline of the condenser at the outlet of the second CRF pump. The third check valve is connected to the third electric isolation valve, and the second booster pump is connected to the fourth electric isolation valve via the fourth check valve.

[0008] After the first to fourth electric isolation valves converge, they split into two paths: one path goes through the fifth electric isolation valve, the automatic cleaning filter, and the sixth electric isolation valve; the other path goes through the seventh electric isolation valve, the bypass filter, and the eighth electric isolation valve. After the two paths converge, they connect to the heat exchanger bypass flow regulating valve, three sets of SRI water temperature control regulating valves, and three sets of CVI coolers.

[0009] The three sets of SRI water temperature control regulating valves are connected to the three sets of SRI heat exchangers; the heat exchanger bypass regulating valve, the three sets of SRI heat exchangers, and the three sets of CVI coolers are all connected to the downstream pipeline of the CRF pump outlet condenser.

[0010] One possible implementation also includes:

[0011] The controller is used to detect the temperature of the cooling water in the first SRI heat exchanger, the temperature of the cooling water in the second SRI heat exchanger, and the temperature of the cooling water in the third SRI heat exchanger; if the temperature of the cooling water in any of the first, second, and third SRI heat exchangers is higher than a first preset temperature, the controller controls at least one of the first or second booster pumps to be in working condition.

[0012] In one possible implementation, the controller is further configured to:

[0013] If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than the second preset threshold, the first booster pump and the second booster pump are controlled to be in a non-working state.

[0014] In one possible implementation, the controller is further configured to:

[0015] If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than a first preset threshold, and the temperature of the cooling water in any one of the first, second, and third SRI heat exchangers is higher than a third preset threshold, a prompt message will be displayed to manually start the first booster pump and the second booster pump.

[0016] In one possible implementation, the controller is further configured to:

[0017] If the first booster pump is in working condition and the second booster pump is in non-working condition, and the first booster pump malfunctions, the second booster pump will be controlled to be in working condition.

[0018] In one possible implementation, the controller is further configured to:

[0019] If the temperature of the cooling water in any of the first, second, and third SRI heat exchangers is higher than the fourth preset temperature, a high-temperature alarm message will be played.

[0020] In one possible implementation, no CVI orifice plate is arranged in the pipe between the second end of the first CVI cooler, the second end of the second CVI cooler, the second end of the third CVI cooler, and the downstream pipe of the CRF pump outlet condenser.

[0021] In one possible implementation, no SRI orifice plate is arranged in the pipe between the second end of the first SRI heat exchanger, the second end of the second SRI heat exchanger, the second end of the third SRI heat exchanger, and the downstream pipe of the CRF pump outlet condenser.

[0022] In one possible implementation, the preset temperature threshold is 29°C.

[0023] In one possible implementation, the opening degree of the first SRI water temperature control valve, the second SRI water temperature control valve, and the third SRI water temperature control valve is all 100%.

[0024] Using the above technical solution, this application provides a nuclear power plant auxiliary cooling water SEN system, which relates to the field of cooling water in nuclear power plants. In order to save energy, the SEN system in the related technology has been improved by shutting down the third booster pump, the fourth booster pump, the three SRI orifice plates and the three CVI orifice plates, thereby reducing the resistance to seawater flow and realizing "passive" water replenishment. That is, even when the first booster pump and the second booster pump are not in operation, sufficient seawater can still be supplied to the SRI heat exchanger and the CVI cooler. Attached Figure Description

[0025] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0026] Figure 1 A schematic diagram illustrating one implementation of a nuclear power plant auxiliary cooling water (SEN) system in the related technology provided in this application embodiment;

[0027] Figure 2 A graph showing the seawater temperature at a nuclear power plant in a northern region in August, provided for an embodiment of this application;

[0028] Figure 3 A schematic diagram illustrating one implementation of a nuclear power plant auxiliary cooling water SEN system provided in this application embodiment;

[0029] Figure 4 The embodiments provided in this application are related to Figure 1 A schematic diagram of the corresponding mathematical model. Detailed Implementation

[0030] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0031] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0032] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0033] like Figure 1 The diagram shown is a schematic representation of one implementation of a nuclear power plant auxiliary cooling water (SEN) system in the related technology provided in this application embodiment.

[0034] like Figure 1 As shown, the SEN system in the related technology includes: a first check valve 005VC, a first electrically operated isolation valve 009VC, a first booster pump 201PO, a second check valve 006VC, a second electrically operated isolation valve 010VC, a third check valve 007VC, a third electrically operated isolation valve 011VC, a second booster pump 401PO, a fourth check valve 008VC, a fourth electrically operated isolation valve 012VC, a fifth electrically operated isolation valve 034VC, an automatic cleaning filter 001FI, a sixth electrically operated isolation valve 035VC, a seventh electrically operated isolation valve 036VC, a bypass filter 002FI, and an eighth electrically operated... Isolation valve 037VC, heat exchanger bypass flow regulating valve 143VC, first SRI water temperature control regulating valve 131VC, second SRI water temperature control regulating valve 121VC, third SRI water temperature control regulating valve 111VC, first SRI heat exchanger SRI101RF, second SRI heat exchanger SRI201RF, third SRI heat exchanger SRI30IRF, first CVI cooler CVI101EX, second CVI cooler CVI201EX, third CVI cooler CVI301EX, third booster pump 101PO, fourth booster pump 301PO.

[0035] Specifically, the first end of the third booster pump 101PO is connected to the upstream pipeline of the condenser at the outlet of the first CRF pump; the second end of the third booster pump 101PO is connected to the first end of the first check valve 005VC; the second end of the first check valve 005VC is connected to the first end of the first electric isolation valve 009VC; the first end of the first booster pump 201PO is connected to the upstream pipeline of the condenser at the outlet of the first CRF pump; the second end of the first booster pump 201PO is connected to the first end of the second check valve 006VC; the second end of the second check valve 006VC is connected to the first end of the second electric isolation valve 010VC; and the port connected to the upstream pipeline of the condenser at the outlet of the first CRF pump is the inlet of the SEN system.

[0036] Specifically, the first end of the fourth booster pump 301PO is connected to the upstream pipeline of the condenser at the outlet of the second CRF pump; the second end of the fourth booster pump 301PO is connected to the first end of the third check valve 007VC; the second end of the third check valve 007VC is connected to the first end of the third electric isolation valve 011VC; the first end of the second booster pump 401PO is connected to the upstream pipeline of the condenser at the outlet of the second CRF pump; the second end of the second booster pump 401PO is connected to the first end of the fourth check valve 008VC; the second end of the fourth check valve 008VC is connected to the first end of the fourth electric isolation valve 012VC; and the port connected to the upstream pipeline of the condenser at the outlet of the second CRF pump is the inlet of the SEN system.

[0037] Among them, the upstream pipeline of the first CRF pump outlet condenser and the upstream pipeline of the second CRF pump outlet condenser belong to the CRF (Cold Water System) system.

[0038] For example, a CRF system includes, but is not limited to: circulating water pumps, motors, couplings, gearboxes, pump bodies, and equipment and systems such as SRI, SEP, and SAT. For example, a CRF system includes two circulating water pumps; one circulating water pump corresponds to the upstream pipe of the condenser at the outlet of the first CRF pump, and the other circulating water pump corresponds to the upstream pipe of the condenser at the outlet of the second CRF pump.

[0039] The second ends of the first electric isolation valve 009VC, the second electric isolation valve 010VC, the third electric isolation valve 011VC, and the fourth electric isolation valve 012VC are respectively connected to the first ends of the fifth electric isolation valve 034VC and the seventh electric isolation valve 036VC; the second end of the fifth electric isolation valve 034VC is connected to the first end of the automatic cleaning filter 001FI; the second end of the automatic cleaning filter 001FI is connected to the first end of the sixth electric isolation valve 035VC; the second end of the seventh electric isolation valve 036VC is connected to the first end of the bypass filter 002FI; the bypass... The second end of filter 002FI is connected to the first end of the eighth electric isolation valve 037VC; the second ends of the sixth electric isolation valve 035VC and the eighth electric isolation valve 037VC are respectively connected to the first ends of the heat exchanger bypass flow regulating valve 143VC, the first end of the first SRI water temperature control regulating valve 131VC, the first end of the second SRI water temperature control regulating valve 121VC, the first end of the third SRI water temperature control regulating valve 111VC, the first end of the first CVI cooler CVI101EX, the first end of the second CVI cooler CVI201EX, and the first end of the third CVI cooler CVI301EX.

[0040] The first end of the first SRI water temperature control regulating valve 131VC is connected to the first end of the first SRI heat exchanger SRI101RF; the first end of the second SRI water temperature control regulating valve 121VC is connected to the first end of the second SRI heat exchanger SRI201RF; the first end of the third SRI water temperature control regulating valve 111VC is connected to the first end of the third SRI heat exchanger SRI301RF; the second end of the heat exchanger bypass flow regulating valve 143VC is connected to the first end of the first SRI heat exchanger SRI101RF. The second end of the second SRI heat exchanger SRI201RF and the second end of the third SRI heat exchanger SRI301RF are respectively connected to the downstream pipeline of the CRF pump outlet condenser; the second end of the first CVI cooler CVI101EX, the second end of the second CVI cooler CVI201EX, and the second end of the third CVI cooler CVI301EX are respectively connected to the downstream pipeline of the CRF pump outlet condenser; the port connected to the downstream pipeline of the CRF pump outlet condenser is the outlet of the SEN system.

[0041] Specifically, a CVI orifice plate is installed in the pipe connecting the second end of the first CVI cooler CVI101EX to the downstream pipe of the CRF pump outlet condenser; a CVI orifice plate is installed in the pipe connecting the second end of the second CVI cooler CVI201EX to the downstream pipe of the CRF pump outlet condenser; and a CVI orifice plate is installed in the pipe connecting the second end of the third CVI cooler CVI301EX to the downstream pipe of the CRF pump outlet condenser.

[0042] Specifically, an SRI orifice plate is installed in the pipe connecting the second end of the first SRI heat exchanger SRI101RF to the downstream pipe of the CRF pump outlet condenser; an SRI orifice plate is installed in the pipe connecting the second end of the second SRI heat exchanger SRI201RF to the downstream pipe of the CRF pump outlet condenser; and an SRI orifice plate is installed in the pipe connecting the second end of the third SRI heat exchanger SRI301RF to the downstream pipe of the CRF pump outlet condenser.

[0043] For example, one of the first, second, and third CVI coolers is in operation, while the other two are in standby mode, i.e., one is in operation and the other two are in standby mode.

[0044] For example, in the first, second, and third SRI heat exchangers, two SRI water heaters are in operation, and one SRI water heater is in standby mode, i.e., two in operation and one on standby. Figure 1 In the process, the first SRI heat exchanger SRI101RF and the third SRI heat exchanger SRI30IRF are in operation, while the second SRI heat exchanger SRI201RF is in standby mode.

[0045] The implementation principle of the SEN system in the relevant technology will be explained below in conjunction with the above structure.

[0046] Any one of the aforementioned booster pumps—the first booster pump 201PO, the second booster pump 401PO, the third booster pump 101PO, and the fourth booster pump 301PO—is used to provide the necessary pressure to the SEN system, ensuring that seawater can flow through the entire SEN system. For example, the booster pump converts mechanical energy into the kinetic and pressure energy of the seawater through the rotation of its impeller, thereby achieving the circulation of seawater.

[0047] The 001FI automatic cleaning filter is used to automatically remove impurities and particulate matter from seawater to prevent these impurities from entering the system and potentially damaging other equipment. It uses an automatic cleaning mechanism to periodically remove impurities from the filter screen, keeping the seawater flow unobstructed.

[0048] The bypass filter 002FI provides additional filtration protection during maintenance or cleaning of the automatic cleaning filter 001FI. It allows seawater to flow without passing through the automatic cleaning filter 001FI, thus ensuring the continuous operation of the SEN system.

[0049] Any one of the following SRI heat exchangers—the first SRI101RF, the second SRI201RF, and the third SRI30IRF—is used to provide cooling water for the conventional island closed-loop cooling water system (SRI). The SRI heat exchanger absorbs heat from the SRI through heat exchange, lowering the water temperature and ensuring that the SRI can operate at a suitable temperature.

[0050] Any one of the three CVI coolers—CVI101EX (first), CVI201EX (second), and CVI301EX (third)—is used to ensure efficient operation of the vacuum pump by lowering the temperature of the sealing water, and also helps maintain the vacuum level of the entire CVI system. The CVI system consists of three parallel pumping systems and a vacuum breaking system. The pumping systems include a two-stage water ring electric vacuum pump, a water vapor separator, a sealing water pump, a sealing water cooler, and a vacuum measurement system.

[0051] The CRF system extracts seawater from the sea and inputs it into the SEN system through the upstream pipes of the first CRF pump outlet condenser and the second CRF pump outlet condenser. The seawater flows through the CVI cooler and SRI heat exchanger in the SEN system, carrying away the heat from the CVI cooler and SRI heat exchanger, thereby achieving the purpose of cooling the CVI cooler and SRI heat exchanger.

[0052] For example, the capacity of any one of the first SRI heat exchanger SRI101RF, the second SRI heat exchanger SRI201RF, and the third SRI heat exchanger SRI30IRF can be 50.

[0053] For example, the capacity of the first booster pump 201PO, the second booster pump 401PO, the third booster pump 101PO, and the fourth booster pump 301PO is 50%.

[0054] Of the first booster pump 201PO and the third booster pump 101PO, one is in operation and the other is in standby. For example, if the first booster pump 201PO fails, the third booster pump 101PO can be used to replace the first booster pump 201PO.

[0055] Of the two booster pumps, the second booster pump 401PO and the fourth booster pump 301PO, one is in operation and the other is in standby. For example, if the second booster pump 401PO fails, the fourth booster pump 301PO can be used to replace the second booster pump 401PO.

[0056] In the relevant technology, two of the first booster pump 201PO, the third booster pump 101PO, the second booster pump 401PO, and the fourth booster pump 301PO are in operation, and the other two are in standby.

[0057] The SEN system in related technologies is used in areas with relatively high seawater temperatures, such as the Greater Bay Area where the seawater temperature is 31.5°C. If the SEN system is used in areas where the seawater temperature is lower than a preset temperature threshold, such as northern regions, the seawater flow rate required by the SRI heat exchanger and CVI heat exchanger will also be reduced due to the low seawater temperature.

[0058] For example, in actual testing, the average seawater temperature at a nuclear power plant in a certain northern region was 13°C, and the highest seawater temperature was 29°C. Figure 2 The figure shown is a graph of seawater temperature at a nuclear power plant in a northern region in August, provided in an embodiment of this application.

[0059] like Figure 2 As shown, in August, the hottest month in this northern region, the highest seawater temperature reaches 29°C. Due to the lower seawater temperature, the required seawater flow rate for the SRI and CVI heat exchangers is also reduced.

[0060] Combination Figure 1 It is known that if the SEN system in the relevant technology is applied to the northern region, then two of the four booster pumps (first booster pump 201PO, third booster pump 101PO, second booster pump 401PO, and fourth booster pump 301PO) are in operation, while the other two are in standby. Due to the large seawater flow, even after meeting the needs of two SRI heat exchangers and three CVI coolers, there is still excess seawater. Therefore, the opening of the heat exchanger bypass flow regulating valve 143VC is controlled at 100% to allow the excess seawater to flow into the downstream pipe of the CRF pump outlet condenser. Furthermore, when the seawater temperature is low in winter, the opening of the SRI water temperature control regulating valve at the SRI heat exchanger inlet is only 13%; this means that a large amount of seawater does not participate in the heat exchange between the SRI heat exchangers and CVI coolers, and is directly pumped from the sea to a conventional island and then discharged back into the sea, resulting in energy waste.

[0061] Combination Figure 2 It can be seen that, Figure 2 The relevant information is shown in the table below.

[0062] Table 1 Figure 2 Related information

[0063]

[0064] To reduce energy waste, this application provides a nuclear power plant auxiliary cooling water (SEN) system.

[0065] like Figure 3 The diagram shown is a schematic representation of one implementation of the nuclear power plant auxiliary cooling water SEN system provided in this application embodiment.

[0066] The SEN system is used in areas where the seawater temperature is below a preset temperature threshold. For example, the preset temperature threshold is 29°C.

[0067] The SEN system in this application includes: a first check valve 005VC, a first electrically operated isolation valve 009VC, a first booster pump 201PO, a second check valve 006VC, a second electrically operated isolation valve 010VC, a third check valve 007VC, a third electrically operated isolation valve 011VC, a second booster pump 401PO, a fourth check valve 008VC, a fourth electrically operated isolation valve 012VC, a fifth electrically operated isolation valve 034VC, an automatic cleaning filter 001FI, a sixth electrically operated isolation valve 035VC, a seventh electrically operated isolation valve 036VC, and a bypass filter 0. 02FI, Eighth Electric Isolation Valve 037VC, Heat Exchanger Bypass Flow Control Valve 143VC, First SRI Water Temperature Control Valve 131VC, Second SRI Water Temperature Control Valve 121VC, Third SRI Water Temperature Control Valve 111VC, First SRI Heat Exchanger SRI101RF, Second SRI Heat Exchanger SRI201RF, Third SRI Heat Exchanger SRI301RF, First CVI Cooler CVI101EX, Second CVI Cooler CVI201EX, Third CVI Cooler CVI301EX.

[0068] Wherein, the first end of the first check valve is connected to the upstream pipeline of the condenser at the outlet of the first CRF pump; the second end of the first check valve is connected to the first end of the first electrically operated isolation valve; the first end of the first booster pump is connected to the upstream pipeline of the condenser at the outlet of the first CRF pump; the second end of the first booster pump is connected to the first end of the second check valve; the second end of the second check valve is connected to the first end of the second electrically operated isolation valve; the port connected to the upstream pipeline of the condenser at the outlet of the first CRF pump is the inlet of the SEN system.

[0069] The first end of the third check valve is connected to the upstream pipeline of the condenser at the outlet of the second CRF pump; the second end of the third check valve is connected to the first end of the third electric isolation valve; the first end of the second booster pump is connected to the upstream pipeline of the condenser at the outlet of the second CRF pump; the second end of the second booster pump is connected to the first end of the fourth check valve; the second end of the fourth check valve is connected to the first end of the fourth electric isolation valve; the port connected to the upstream pipeline of the condenser at the outlet of the second CRF pump is the inlet of the SEN system.

[0070] The second ends of the first, second, third, and fourth electric isolation valves are respectively connected to the first ends of the fifth and seventh electric isolation valves; the second end of the fifth electric isolation valve is connected to the first end of the automatic cleaning filter; the second end of the automatic cleaning filter is connected to the first end of the sixth electric isolation valve; the second end of the seventh electric isolation valve is connected to the first end of the bypass filter; the second end of the bypass filter is connected to the first end of the eighth electric isolation valve; the second ends of the sixth and eighth electric isolation valves are respectively connected to the first ends of the heat exchanger bypass flow regulating valve, the first ends of the first, second, and third SRI water temperature controlling valves, the first ends of the first, second, and third CVI coolers.

[0071] The first end of the first SRI water temperature control regulating valve is connected to the first end of the first SRI heat exchanger; the first end of the second SRI water temperature control regulating valve is connected to the first end of the second SRI heat exchanger; the first end of the third SRI water temperature control regulating valve is connected to the first end of the third SRI heat exchanger; the second end of the heat exchanger bypass flow regulating valve, the second end of the first SRI heat exchanger, the second end of the second SRI heat exchanger, and the second end of the third SRI heat exchanger are respectively connected to the downstream pipeline of the CRF pump outlet condenser; the second end of the first CVI cooler, the second end of the second CVI cooler, and the second end of the third CVI cooler are respectively connected to the downstream pipeline of the CRF pump outlet condenser; the port connected to the downstream pipeline of the CRF pump outlet condenser is the outlet of the SEN system.

[0072] Seawater in the upstream pipe of the first CRF pump outlet condenser and seawater in the upstream pipe of the second CRF pump outlet condenser enter the SEN system through the inlet of the SEN system and flow out through the outlet of the SEN system.

[0073] Combination Figure 3It can be seen that no CVI orifice plates are arranged in the pipes deployed between the second end of the first CVI cooler, the second end of the second CVI cooler, the second end of the third CVI cooler, and the downstream pipe of the CRF pump outlet condenser. Similarly, no SRI orifice plates are arranged in the pipes deployed between the second end of the first SRI heat exchanger, the second end of the second SRI heat exchanger, the second end of the third SRI heat exchanger, and the downstream pipe of the CRF pump outlet condenser.

[0074] The following section explains, in conjunction with various operating modes of the SEN system provided in this application, why the SEN system provided in this application can save energy.

[0075] The first working mode: the first and second booster pumps in the SEN system are in a non-working state, that is, "passive" water replenishment is achieved.

[0076] "Passive" water replenishment refers to the SEN system's ability to replenish seawater through natural circulation even when both the first and second booster pumps are not in operation.

[0077] Compared to Figure 1 The SEN system provided in this application shuts down the third booster pump 101PO and the fourth booster pump 301PO, removes three SRI orifice plates and three CVI orifice plates, that is, removes the flow-through components, thereby reducing the resistance to seawater flow and realizing "passive" water replenishment. That is, even when the first booster pump and the second booster pump are not in operation, sufficient seawater can still be supplied to the SRI heat exchanger and the CVI cooler.

[0078] The reason why sufficient seawater can be supplied to the SRI heat exchanger and CVI cooler in the first operating mode will be explained below. For example, the following explanation uses any one of the first, second, and third SRI heat exchangers as an example.

[0079] The following explanation uses a preset temperature threshold of 29°C. Based on a series of parameters, including the power of the SRI heat exchanger, the thermal conductivity of seawater, the specific heat of seawater, the density of seawater, the fluid type of seawater, the dynamic viscosity of seawater, the inlet temperature of the SRI heat exchanger, and the outlet temperature of the SRI heat exchanger (as shown in Table 2), the required seawater flow rate for each SRI heat exchanger is calculated.

[0080] Table 2 Parameters for SRI heat exchangers

[0081]

[0082] Using the parameters shown in Table 2, taking a seawater temperature of 29°C and an SRI heat exchanger outlet temperature of 36.5°C as an example, the required seawater flow rate for each SRI heat exchanger is calculated to be 1200 m³ / h.

[0083] exist Figure 1 Based on the structure of the SEN system shown, after shutting down the first, second, third, and fourth booster pumps, the seawater flow rate through the SRI heat exchanger was detected to be approximately 988 m³ / h. Since 988 m³ / h < 1200 m³ / h, it is necessary to dismantle... Figure 1 The flow-through components in the system reduce the resistance to seawater flow and enable "passive" water replenishment, meaning that even when both the first and second booster pumps are not in operation, sufficient seawater can still be supplied to the SRI heat exchanger and CVI cooler.

[0084] For example, after shutting down the third and fourth booster pumps, three SRI orifice plates, and three CVI orifice plates, the calculated seawater flow rate through each SRI heat exchanger was 1342 m³ / h, meeting the requirements of the SRI heat exchangers. During actual testing, the measured seawater flow rate through each SRI heat exchanger was 1212.15 m³ / h, also meeting the requirements. Since its deployment in the field in 2021, the SEN system has achieved high-end stable operation for five years.

[0085] The following explains the calculation process for the seawater flow rate of 1342 m³ / h through each SRI heat exchanger.

[0086] This application uses pre-set software to establish a mathematical model, which is consistent with... Figure 1 The structures are the same.

[0087] like Figure 4 As shown, this application provides an embodiment of the technology related to... Figure 1 A schematic diagram of the corresponding mathematical model.

[0088] Understandably, mathematical models can help engineers analyze and design the layout and component configuration of SEN systems to ensure that the SEN system can effectively provide the required seawater for SRI heat exchangers and CVI coolers.

[0089] Mathematical models can predict the performance of a SEN system under different operating conditions, such as varying flow rates, pressures, and temperatures, including flow distribution, pressure losses, and energy efficiency. These models can be used to optimize SEN system operation, for example, by adjusting pump operating modes and valve openings, to achieve more efficient energy utilization and lower operating costs.

[0090] Mathematical models can help assess the risks and impacts of SEN systems under different failure modes, such as complete pump shutdown or valve failure, thereby enabling the development of corresponding prevention and response measures.

[0091] Understandable, Figure 1 The outlet of the SEN system is connected to the downstream pipeline of the CRF pump outlet condenser, so the outlet pressure of the SEN system cannot be measured. Although the inlet pressure of the SEN system can be detected, the pressure difference between the inlet and outlet cannot be measured because the outlet pressure cannot be detected, thus preventing the measurement of the pressure difference. Figure 4 The mathematical model shown detects the seawater flow rate through the SRI heat exchanger. In order to be able to... Figure 4 The mathematical model shown detects the seawater flow rate through the SRI heat exchanger. This application determines the outlet pressure of the SEN system using the following method.

[0092] Combination Figure 1 The SEN system shown can detect the contents shown in Table 3.

[0093] Table 3 Figure 1 The seawater flow rate corresponding to the SEN system shown is

[0094]

[0095] Based on a seawater temperature ceiling of 29℃ and a seawater flow rate of 1000 m³ / h, the calculated outlet temperature of the SRI heat exchanger is 37.65℃, which is higher than the design value of 36.5℃. From the experimental data in Table 2, Figure 1 After the four booster pumps in the SEN system shown are shut down, if one SRI heat exchanger is in operation, its flow rate is approximately 988 m³ / h. If two SRI heat exchangers are in operation, their combined flow rate is approximately 1853 m³ / h. If three SRI heat exchangers are in operation, their combined flow rate is approximately 2603 m³ / h.

[0096] In order to detect Figure 1 The outlet pressure of the SEN system shown is changed using the parameters in Table 3. Figure 4 The mathematical model shown represents the pressure at the outlet; it is understandable that setting... Figure 4 The pressure at the inlet of the mathematical model shown is Figure 1 The pressure at the inlet of the SEN system shown; adjustment Figure 4 The pressure at the outlet of the mathematical model shown is such that... Figure 4 The mathematical model shown satisfies the parameters in Table 3. In determining... Figure 4 After the pressure at the outlet of the mathematical model shown, it is possible to... Figure 4In the mathematical model shown, the flow-through components are removed, for example, the third booster pump, the fourth booster pump, the three SRI orifice plates, and the three CVI orifice plates are removed to obtain... Figure 3 The corresponding mathematical model of the SEN system was used, and then simulation tests were conducted by removing the mathematical model of the flow-through components. The test results are shown in Table 4.

[0097] Table 4. Test results of simulation tests using a mathematical model with the flow-through components removed.

[0098]

[0099] The main pipe flow rate in Table 4 refers to... Figure 3 The flow rate of seawater in the main pipeline.

[0100] As shown in Table 4, if it is necessary to ensure that the seawater flow rate through each SRI heat exchanger is higher than 1200 m³ / h and to save energy, then the following should be selected: "The two circulating water pumps in the CRF system are in working condition; the first booster pump and the second booster pump are in non-working condition".

[0101] The applicant has been in the process since 2021. Figure 3 The SEN system shown is in a condition where "two circulating water pumps in the CRF system are operating; the first and second booster pumps are not operating." Because the first and second booster pumps are not operating, calculations indicate that this project will increase power generation by approximately 3.5 million yuan annually (approximately 10 million kilowatt-hours), and save over 1 million yuan in operation and maintenance costs. Simultaneously, it solves... Figure 1 The following problems exist in the SEN system:

[0102] When two booster pumps are running in standby mode, the booster pumps vibrate excessively during standby, causing defects such as pump set unusability and shaft breakage; equipment such as the heat exchanger bypass flow regulating valve 143VC experiences significant vibration in winter, with frequent occurrences of gas source pipe detachment; and the main pipeline and filter experience occasional large vibrations.

[0103] As of 2024, Figure 3 The first and second booster pumps in the SEN system shown have been shut down for more than four years, during which time they experienced four summers without any abnormalities.

[0104] Understandable, Figure 3 The opening degree of the first SRI water temperature control valve 131VC, the second SRI water temperature control valve 121VC, and the third SRI water temperature control valve 111VC in the SEN system shown is 100%.

[0105] In an optional implementation, the embodiments of this application provide Figure 3The SEN system shown is mostly in the state where "two circulating water pumps in the CRF system are in working condition; the first booster pump and the second booster pump are in non-working condition", and the opening degree of the first SRI water temperature control regulating valve 131VC, the second SRI water temperature control regulating valve 121VC, and the third SRI water temperature control regulating valve 111VC is 100%.

[0106] The second operating mode: If the outlet temperature of the SRI heat exchanger is high, the first booster pump and / or the second booster pump can be controlled to be in operation, thereby increasing the seawater flow through the SRI heat exchanger.

[0107] For example, the outlet of the SRI heat exchanger has a detection point, which can detect the temperature of the SRI001MT detection point, and this temperature characterizes the temperature of the SRI heat exchanger outlet.

[0108] In one alternative implementation, the nuclear power plant auxiliary cooling water SEN system further includes:

[0109] The controller is used to detect the temperature of the cooling water in the first SRI heat exchanger, the temperature of the cooling water in the second SRI heat exchanger, and the temperature of the cooling water in the third SRI heat exchanger; if the temperature of the cooling water in any of the first, second, and third SRI heat exchangers is higher than a first preset temperature, the controller controls at least one of the first or second booster pumps to be in working condition.

[0110] For example, the first preset temperature can be determined based on the actual situation, such as 36.5°C.

[0111] In an alternative implementation, the controller is further configured to:

[0112] If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than the second preset threshold, the first booster pump and the second booster pump are controlled to be in a non-working state.

[0113] For example, the second preset threshold can be determined based on the actual situation, such as 32°C.

[0114] In an alternative implementation, the controller is further configured to:

[0115] If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than a first preset threshold, and the temperature of the cooling water in any one of the first, second, and third SRI heat exchangers is higher than a third preset threshold, a prompt message will be displayed to manually start the first booster pump and the second booster pump.

[0116] For example, the third preset threshold can be determined based on the actual situation, such as 35.5°C.

[0117] In an alternative implementation, the controller is further configured to:

[0118] If the first booster pump is in working condition and the second booster pump is in non-working condition, and the first booster pump malfunctions, the second booster pump will be controlled to be in working condition.

[0119] It is understandable that, in order to avoid the rise in sea surface temperatures caused by global warming, the provisions of this application... Figure 3 The SEN system shown is Figure 1 Compared to the SEN system shown, two booster pumps are retained to avoid starting one or both booster pumps when the seawater temperature rises and an increased seawater flow is required.

[0120] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0121] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0122] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

[0123] The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, training device, or data center to another website, computer, training device, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a training device or data center that integrates one or more available media. The available media may be magnetic media (e.g., floppy disks, hard disks, magnetic tapes), optical media (e.g., DVDs), or semiconductor media (e.g., solid-state drives (SSDs)).

Claims

1. A nuclear power plant auxiliary cooling water SEN system, characterized in that, The SEN system is applied in areas where the seawater temperature is below a preset temperature threshold. The SEN system includes: a first check valve, a first electrically operated isolation valve, a first booster pump, a second check valve, a second electrically operated isolation valve, a third check valve, a third electrically operated isolation valve, a second booster pump, a fourth check valve, a fourth electrically operated isolation valve, a fifth electrically operated isolation valve, an automatic cleaning filter, a sixth electrically operated isolation valve, a seventh electrically operated isolation valve, a bypass filter, an eighth electrically operated isolation valve, a heat exchanger bypass flow regulating valve, three sets of SRI water temperature control regulating valves, three sets of SRI heat exchangers, and three sets of CVI coolers. The three sets of SRI water temperature control regulating valves include a first SRI water temperature control regulating valve, a second SRI water temperature control regulating valve, and a third SRI water temperature control regulating valve. The three sets of CVI coolers include a first CVI cooler, a second CVI cooler, and a third CVI cooler. The three sets of SRI heat exchangers include a first SRI heat exchanger, a second SRI heat exchanger, and a third SRI heat exchanger. The first check valve and the first booster pump are both connected to the upstream pipeline of the condenser at the outlet of the first CRF pump. The first check valve is connected to the first electric isolation valve, and the first booster pump is connected to the second electric isolation valve via the second check valve. The third check valve and the second booster pump are both connected to the upstream pipeline of the condenser at the outlet of the second CRF pump. The third check valve is connected to the third electric isolation valve, and the second booster pump is connected to the fourth electric isolation valve via the fourth check valve. After the first to fourth electric isolation valves converge, they split into two paths: one path goes through the fifth electric isolation valve, the automatic cleaning filter, and the sixth electric isolation valve; the other path goes through the seventh electric isolation valve, the bypass filter, and the eighth electric isolation valve. After the two paths converge, they connect to the heat exchanger bypass flow regulating valve, three sets of SRI water temperature control regulating valves, and three sets of CVI coolers. The three sets of SRI water temperature control valves are connected to the three sets of SRI heat exchangers; the heat exchanger bypass control valve, the three sets of SRI heat exchangers, and the three sets of CVI coolers are all connected to the downstream pipeline of the CRF pump outlet condenser.

2. The nuclear power plant auxiliary cooling water SEN system according to claim 1, characterized in that, Also includes: The controller is used to detect the temperature of the cooling water in the first SRI heat exchanger, the temperature of the cooling water in the second SRI heat exchanger, and the temperature of the cooling water in the third SRI heat exchanger; if the temperature of the cooling water in any of the first, second, and third SRI heat exchangers is higher than a first preset temperature, the controller controls at least one of the first or second booster pumps to be in working condition.

3. The nuclear power plant auxiliary cooling water SEN system according to claim 2, characterized in that, The controller is also used for: If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than the second preset threshold, the first booster pump and the second booster pump are controlled to be in a non-working state.

4. The nuclear power plant auxiliary cooling water SEN system according to claim 2, characterized in that, The controller is also used for: If the temperatures of the cooling water in the first SRI heat exchanger, the second SRI heat exchanger, and the third SRI heat exchanger are all lower than a first preset threshold, and the temperature of the cooling water in any one of the first, second, and third SRI heat exchangers is higher than a third preset threshold, a prompt message will be displayed to manually start the first booster pump and the second booster pump.

5. The nuclear power plant auxiliary cooling water SEN system according to claim 2, characterized in that, The controller is also used for: If the first booster pump is in working condition and the second booster pump is in non-working condition, and the first booster pump malfunctions, the second booster pump will be controlled to be in working condition.

6. The nuclear power plant auxiliary cooling water SEN system according to claim 2, characterized in that, The controller is also used for: If the temperature of the cooling water in any of the first, second, and third SRI heat exchangers is higher than the fourth preset temperature, a high-temperature alarm message will be played.

7. The nuclear power plant auxiliary cooling water SEN system according to any one of claims 1 to 6, characterized in that, No CVI orifice plate is arranged in the pipe between the second end of the first CVI cooler, the second end of the second CVI cooler, the second end of the third CVI cooler and the downstream pipe of the CRF pump outlet condenser.

8. The nuclear power plant auxiliary cooling water SEN system according to claim 7, characterized in that, No SRI orifice plates are installed in the pipes between the second end of the first SRI heat exchanger, the second end of the second SRI heat exchanger, the second end of the third SRI heat exchanger, and the downstream pipe of the CRF pump outlet condenser.

9. The nuclear power plant auxiliary cooling water SEN system according to any one of claims 1 to 6, characterized in that, The preset temperature threshold is 29°C.

10. The nuclear power plant auxiliary cooling water SEN system according to any one of claims 1 to 6, characterized in that, The opening degree of the first SRI water temperature control valve, the second SRI water temperature control valve, and the third SRI water temperature control valve is all 100%.

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