KR20010076565A - Passive Secondary Condensing System - Google Patents

Abstract

PURPOSE: A passive secondary condensing system of an atomic power station is provided to safely stop a reactor by a natural circulation without an external power when a total loss of a feed water occurs. CONSTITUTION: A steam generator(20) generates steam due to heat generated in a reactor(10). A main steam line(21) sends the steam from the steam generator through an outside wall(30) of a containment vessel toward a turbine. A steam supply line(40) is diverged from the main steam line(21) and supplies the steam. A condenser(60) condenses the supplied steam. A passive secondary condensing tank(50) settles the condenser(60) in a cooling water and permits a condensing operation. A condensate collecting line(70) collects the condensate from the condenser(60) and sends the same to the steam generator through a main supply line(23). The steam supply line(40) is diverged on a front end of a main steam interrupting valve(22). A condensate discharging valve is connected to a rear end of the main steam interrupting valve(22). A check valve of the condensate collecting line(70) is connected to a front end of the main supply interrupting valve(23).

Description

Passive Secondary Condensing System of Nuclear Power Plant

In the present invention, in the pressurized light water reactor-type nuclear power plant, the nuclear power generator can be cooled using a natural circulation principle that does not require power to cool the steam generator in preparation for the normal operation of the auxiliary water supply system that requires power. A passive secondary condensation system of a power plant.

Nuclear power plants generate heat according to the nuclear fission of fuel, and also control it, so that the heat energy obtained from heat exchange from the steam generator to operate steam turbines and generators to obtain electrical energy is the same as other types of power plants. At the same time, however, the nuclear power plant maintains the safety of the power plant and suppresses radioactive external leakage by keeping the reactor core containing nuclear fuel and the reactor coolant system that transfers generated heat to the secondary side safely and operating within the design criteria. shall. To achieve this, nuclear power plants are equipped with a reactor protection system, an engineering safety feature system, an emergency electrical system, and a containment vessel to safely shut down the plant in the event of an accident. Equipped with the same safety equipment.

Among these safety facilities, the engineering safety system system includes the loss of coolant during accidents that may occur in nuclear power plants, a large number of secondary system pipe ruptures, steam generator tube ruptures, one reactor coolant pump rotor stuck, nuclear fuel handling accidents, control rod drive mechanism protection tube rupture. It is a system that prevents the leakage of nuclear fission products to the maximum by fully exhibiting its unique design function even in the case of accidents of design standards.

Engineering safety facilities include containment systems, emergency core cooling systems, nuclear reactor fission product removal and control systems, and auxiliary feedwater systems. It can be divided into four types.

The auxiliary water supply system, one of these engineering safety installations, provides the main means of preventing core damage by supplying steam generators and cooling the reactor in the event of an accident.

The auxiliary water supply system in the form of a CE power plant consists of two independent sub-systems consisting of a motor drive pump and a turbine drive pump driven directly by a steam turbine. Each subsidiary system is designed to supply water to the steam generator and to supply sufficient water to the steam generator in the event of a main water supply or main steam pipe rupture that can occur simultaneously with a single failure of the auxiliary water supply system.

In the steam generator, steam generated by boiling water supplied through the auxiliary water supply system is discharged to the atmosphere through the main steam atmospheric release valve to remove heat generated in the reactor. Where a condenser is available, steam may be released to the condenser by a turbine bypass system. In this way, when the coolant temperature and pressure are lowered to 177 ° C. and 28.8 kg / cm ² or less, respectively, the cooling function is performed by the stationary cooling system.

The total loss of feedwater (TLOFW) is when these subwater supply systems fail to work or stop during operation.

In case of complete loss of water supply, if the pressure in the reactor coolant system becomes too high to remove heat, the pressure in the primary system will rise. The increased pressure prevents the overpressure by opening the valve when the set pressure of the PSV (Pressurizer Safety Valve) is exceeded. After that, when the pressure falls below the set pressure value, the valve closes. In this way, the valve continues to open and closes repeatedly, and at some point, the operator manually opens the safety pressure reducing valve (SDS) to manually reduce the pressure in the reactor coolant system. The high pressure safety injection pump is activated to inject boric acid into the coolant system to enable safe injection of the reactor coolant inventory. That is, the coolant temperature and pressure are 177 ° C and 28.8kg / cm ^{2 by the} fed and bleed operation using the safety depressurization system (SDS) and the safety injection system (SIS). When it is lowered below, the cooling function is performed by the static cooling system. As such, the existing CE type nuclear power plants (Gwanggwang 3,4, Uljin 3,4) will remove the core heat through feed and bleed in case of complete water supply loss.

However, the operational uncertainty of the equipment for fed and bleed operation using the safety depressurization system (SDS) and the safety injection system (SIS) in the case of complete water supply is putting a heavy burden on the operator. .

Therefore, in order to prevent the above problems in the next generation reactor, the main water supply system and the auxiliary water supply system are inoperable, that is, safely shut down the reactor by natural circulation without external power in the event of a complete water loss. To provide a passive secondary condensation system of a nuclear power plant.

The functions of the passive secondary condensation system of the present invention are achieved by the fully driven operation without operator's manipulation or supply of external AC power. In other words, the passive secondary condensation system may be damaged in the core when the secondary feed system (AFWS) is lost due to a nuclear reactor transient accident or a small break LOCA (SBLOCA). By removing the heat required for cooling the reactor coolant system through the secondary system, it is possible to prevent the leakage of radiation to the outside while preventing core damage without the injection discharge operation by safe injection.

The principle of operation of the driven secondary condensation system operation depends on the film-wise condensation process inside the vertical tube. After system start-up, steam condenses on the cold tube inner wall surface. Since the tube remains submerged in water, the surface temperature is kept sufficiently below the saturation temperature. Steam is removed during the condensation to reduce the local pressure. Steam flows from the steam generator to the condenser because the condenser is connected to a pressurized steam generator containing steam. On the other hand, the condensate is recovered by the drainage and steam generator by gravity to form a continuous and stable condensation process, which enables continuous operation of the driven secondary condensation system. In conjunction with the layout design of the passive secondary condensation system, the head of the condensate is designed to be sufficient to carry out natural circulation.

The passive secondary condensation system is a non-safety class that supplements the auxiliary water supply system rather than the safety grade passive secondary condensation system, which accepts all the functions of the auxiliary water supply system and completely replaces the auxiliary water supply system from a licensing perspective. It consists of one condenser, other valves and piping.

While the system is waiting, close the steam supply valve and open the small bypass valve. This is added by a steam supply line bypass of approximately 3/4 inch to prevent steam hammers that may occur by opening the steam supply line valves in system standby when starting the passive secondary condensation system. In addition, the load caused by the expected failure in the part where the condensate is submerged inside the passive secondary condensation system tank will be significantly reduced. This will reduce the problem of licensing due to pipe rupture at the steam supply line isolation valve outlet. In addition, the steam supply line should be equipped with automatic drainage.

1 is a block diagram of a passive secondary condensation system according to the present invention.

2 is a detailed configuration diagram of a passive secondary condensation system according to the present invention.

Figure 3 is a schematic diagram of the chemical additive loop of the passive secondary condensation system according to the present invention.

4a and 4b is a block diagram showing a condenser of a passive secondary condensation system according to the present invention.

<Description of the code | symbol about the principal part of drawing>

10 reactor 20 steam generator

21: main steam engine 22: main steam shutoff valve

23: main water supply pipe 24: main water supply shutoff valve

30: outer wall of the containment building 40: steam supply pipe

41, 42: steam supply pipe valve 43: steam supply pipe bypass valve

44: steam supply pipe isolating valve 45: steam supply pipe drain valve

46 non-condensable gas exhaust valve 50 passive secondary condensation system (PSCS) tank

60: condenser (heat exchanger) 61a, 61b: condenser module

62: steam distributor 70: condensate recovery pipe

71, 72: condensate return pipe valve 73: condensate return pipe check valve

80: non-condensable gas recovery tube 90: chemical additive loop

91: circulation pump 92: chemical additive tank

93: exit nozzle 94: sample collection pipe

95: chemical addition funnel 96: drainage

97: inlet nozzle 100: moisture separator

110: supplementary water supply means 111: emergency water supply

112: Demi water supply

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a passive secondary condensation system according to the present invention.

There is a main steam engine 21 passing steam from the steam generator 20 that generates steam by heat generated in the reactor 10 to the turbine side through the outer wall 30 of the containment building, and from the steam engine 21, the steam supply pipe ( 40 is branched to supply steam through the steam supply pipe 40. A condenser 60 for condensing the supplied steam, a driven secondary condensation tank 50 for condensing the condenser 60 in cooling water, and condensation operation to be performed, and water condensed from the condenser 60 to recover the main water supply pipe. Consists of the condensate water recovery pipe 70 that serves to send to the steam generator through the 23 and the main water supply pipe 23 for supplying water to the steam generator after turning the turbine. The steam supply pipe 40 is branched from the front end of the main steam shutoff valve (MSIV) 22, the condensate exhaust valve 46 is connected to the rear end of the main steam shutoff valve 22, the condensate recovery pipe ( The check valve 73 of 70 is connected to the front end of the main water supply shutoff valve (23).

Here, the driven secondary condensation tank 50 is installed on the outside of the containment building outer wall 30 and the height of the bottom surface of the driven secondary condensation tank 50, the maximum level of the steam generator or the condensate recovery nozzle height to prevent the condensate ingress The head must be positioned sufficiently higher than the sum of the total head losses at maximum flow. When the condenser 60 is submerged, it entails flow instability between the tubes or flow instability between modules and the heat removal capacity is reduced. This is because single phase heat transfer is much lower in heat transfer efficiency than condensation heat transfer.

2 is a detailed configuration diagram of a passive secondary condensation system according to the present invention.

Steam is received through the steam supply pipe 40 branched from one line of the main steam engine 21 between the containment outer wall 30 and the main steam shutoff valve 22. Steam supply line isolation valve (44) and steam supply line isolation valve (41) for the isolation of the steam supply line. In parallel with (42) there is a steam supply pipe bypass valve (43) for preheating and pressurizing the condenser in the standby state of the driven secondary condensation system. In addition, the loop sealing is performed to branch the drain pipe from the steam supply pipe 40 between the steam supply pipe valves 41 and 42 and the steam supply pipe isolation valve 44 to remove condensed water formed in the steam supply pipe 40 due to heat loss. Equipped with a drain valve 45 and an exhaust pipe for discharging the non-condensable gas from the steam distributor distributed to the two condensation modules at the upper end of the condenser 60 to the main steam engine 21. 46) is included and open in standby.

The condensate return pipe has a condensate return pipe (70) to prevent the secondary secondary condensing system flow from flowing back due to the malfunction of the system atmosphere or the main steam safety valve (MSSV / MSADV) opened during operation of the passive secondary condensation system. ), Check valves (73) were installed, and in particular, in order to reduce the number of isolation valves, it was installed by adopting stop check valves that provide isolation functions. In addition, the system automatically opens upon operation of the driven secondary condensed system, and there are multiple designed condensed recovery tube isolation valves 71 and 72 for isolation from the driven secondary system when the check valve is broken.

In addition, the non-condensable gas recovery pipe 80 of the condenser connected with four direct current valves in series and parallel to exhaust the non-condensable gas accumulated in the lower header of the condenser 60 into the driven secondary condensation system tank 50, and the driven Steam to be released into the atmosphere from the chemical addition loop 90 and the secondary secondary condensation system tank 50 for the anticorrosive injection and purification treatment to prevent thermal degradation due to the propagation of organisms in the secondary condensation system tank 50. There is a moisture separator (100) for recovering the moisture accompanying the water to recover the water back into the tank.

Each valve of the driven secondary condensation system according to the present invention further includes a battery power source to be driven even when the main power supply and the emergency auxiliary power supply are always used, and DC power supply valves are used.

3 is a schematic diagram of a chemical additive loop of a driven secondary condensation system according to the present invention. As shown in FIG. 2, the tank recirculation pump 91 takes the water of the driven secondary condensation system tank 50 from the suction nozzle 97 to prevent corrosion. It is possible to recirculate back into the tank through the outlet nozzle (93) by the addition. The hydrogen peroxide concentration is periodically checked through the sampling furnace 94, and when the reference value (50 ppm) is out of the standard, the recycling pump 91 is stopped to receive the chemical through the chemical addition funnel 95, and the chemical addition tank 92 ) By adjusting the concentration of the system by supplying or by draining the water through the drainage passage (96) and recycle again to meet the reference value. In addition, the water level is controlled by supplying the water in the passive secondary condensation system tank through emergency water suppy 111 and pure water supply 112.

4a and 4b is a block diagram showing a condenser of a passive secondary condensation system according to the present invention. The driven secondary condensation system tank 50 acts as a heat source of the condenser 60. The driven secondary condensation system condenser 60 is composed of a steam distributor 62 and two modules 61a and 61b. Each module consists of a vertical tube and an upper header / lower header. Inside the tube, heat is transferred by two-phase natural circulation flow, and outside is by boiling.

Referring to the functional requirements and the operation of each of the components of the passive secondary condensation system of the present invention configured as described above are as follows.

The driven secondary condensing system condenser 60 transmits the residual heat to the tank as a heat source of the abnormal natural circulation circuit. The condenser 60 is composed of a steam distributor 62 for distributing steam to two condenser modules and two modules 61a and 61b acting as heat exchangers. Each module 61a, 61b consists of a vertical tube and an upper header / lower header through which steam is condensed. Steam condenses on the inner wall of the cold tube and vapor is removed in the condensation process, reducing the local pressure, and the steam continues to flow from the steam generator to the condenser and the condensate is returned to the steam generator by gravity to form a continuous and stable condensation process. do.

Moisture Separator (100) is a device for recovering the water contained in the steam discharged to the atmosphere during the operation of the driven secondary condensation system. The moisture separator 100 reduces the tank capacity as it can cool the condenser with a relatively small amount of water as the water is recovered from the steam.

The chemical addition loop 90 injects a bio-fouling inhibitor to prevent the degradation of thermal efficiency by living things in the driven secondary condensation system tank 50 using the circulation pump 91. This is because condenser heat removal is reduced when organisms adhere to the outside of the condenser tube surface. Regarding tank cleaning operations, the water quality should be maintained to meet the hydrogen peroxide concentration requirements (50 ppm) and the desalter water quality requirements for algae control in the tank. Therefore, a purification system as shown in FIG. 3 is required. Water quality is monitored periodically by grab sampling. As a result of sample analysis, if the hydrogen peroxide concentration is below the reference value, the recirculation pump 91 is stopped, the isolation valve is shut off, the chemical addition tank 92 is exhausted and drained, the necessary chemical is added through the funnel, and the purification operation is performed. Rearrange the system for The passive secondary condensation system operation is not subject to any restrictions due to water quality, but if the water quality is outside the standard, it is very likely that algae will breed in the passive secondary condensation system tank, ultimately affecting condenser performance due to reduced thermal efficiency area. There is a possibility. Periodic sampling is used to monitor the quality of the water quality. Loop pipes are sized according to the secondary secondary condensing system tank capacity and type of operation (continuous or intermittent operation).

And the valves of the driven secondary condensation system, as shown in Figure 2, steam supply pipe valve 41, 42, condensate return pipe valve 72, condensate return pipe check valve 73, steam supply pipe bypass valve 43 There are steam supply pipe drain valve (45) and non-condensable gas exhaust valve. They are operated with Class 1E DC power and use battery power as auxiliary power. This is to operate even if the main power source or auxiliary power of the nuclear power plant is lost, it is configured to operate each DC drive valve by having a battery power as an emergency power supply to maintain the state of charge by the normal power supply.

The valves 41, 42, 44/71, 72. 73 serving as the steam supply pipe 40 / condensate recovery pipe 70 isolate the steam generator from loss of inventory due to breakage of the outlet of the isolation valve during system operation. To design multiple.

The condensate return pipe check valve 73, if the check valve is not installed in the condensate return pipe 70, the reverse flow due to malfunction may immerse the main steam pipe and damage the turbine and the main steam pipe. In addition, when the secondary secondary condensation system is in operation, when the MSSV (Main Steam Safety Valve) / MSADV (Main Steam Atmospheric Dump Valve) is opened, backflow may flood the condenser and the steam supply pipe 40. When the condenser is submerged, it is accompanied by flow vibrations inside the condenser. Water slug in the steam supply line 40 and the main steam line can damage the piping and condenser when the secondary secondary condensation system is restarted. It is required to install a check valve in the condensate return pipe 70 to prevent backflow of the driven secondary condensed system flow due to MSSV / MSADV opening during malfunction or system operation. In particular, in order to reduce the number of isolation valves, a stop check valve 73 is provided that provides isolation functions.

The steam supply bypass valve 43 is designed to pressurize the condenser during system atmospheric conditions.

The steam supply pipe drain valve 45 installs a drain pipe and a drain valve with a loop seal in the steam supply pipe 40 to remove condensed water formed in the steam supply pipe 40 due to heat loss.

The non-condensable gas exhaust valve 46 must be completely removed for system operation because the non-condensable gas greatly degrades the heat removal capability of the condenser. In the system atmosphere, non-condensable gases are exhausted from the steam distributor, the highest point in the system, to the main steam pipe. Thus, the non-condensable gas exhaust valve is left open in system standby.

In addition, the passive secondary condensation system tank 50 further includes a non-condensable gas exhaust loop 80, which is installed in the non-condensable gas because the flow area is rapidly reduced from the lower header to the condenser drain pipe during system operation. Accumulates in. Non-condensable gases are exhausted from the lower header of the condenser to the passive secondary condensing system tank while the system is running. Opening and closing of the non-condensable gas exhaust valve is automatically performed by the steam generator pressure setpoint. DC power is supplied to the non-condensable gas exhaust valve because a valve start is required for system operation.

Normal and emergency replenishment water supply means 110, the normal replenishment of the driven secondary condensed system tank 50 water is required to compensate for the loss by evaporation during the system atmosphere. Normal replenishment is automatically supplied from the demineralized replenishment system using the tank level setpoint. Emergency replenishment of the driven secondary condensation system tank 50 is necessary to replenish the tank again until a safe stop entry condition is reached. It is configured to connect the emergency water supply 111 and the normal water supply 112 for demineralized water supply to the chemical addition system as shown in FIG.

As the driven secondary condensed system operating system, the driven secondary condensed system operating signal is the main steam shutoff valve (MSIV), the main steam shutoff valve bypass valve (MSIVBV), the drain isolation valve, and the AF pump of the main steam system to form a closed loop. Close the turbine steam supply valve, the steam generator blowoff system containment building containment valve, and the steam generator blowoff pipe sampling tube isolation valve. The above valves are safety class valves that must be closed upon MSIS signal. Therefore, in order to meet the protection and control system disconnection requirements of 10 CFR 50, Annex A, GDC 24, the PSCSAS shall be rated for safety.

There are two steam generators in the next-generation reactor, and each steam generator is connected with two main steam lines (MSL) 21 and two feedwater lines 23. The passive secondary condensation system closed circuits installed in the main steam pipe of each loop are identical and independent of each other. Each passive secondary condensation system closed circuit includes a steam supply line 40, a condenser 60, that is, a heat exchanger, a condenser, a condensate return line, and a DC-operated valve. It consists of). The heat exchanger condenser 60 is a bundle of vertical tubes immersed in the pool of the driven secondary condensation system tank 50 located above the main steam valve house (MSVH), and It consists of an upper and lower header (Header, or Plenum) connected up and down to the bundles. The steam supply pipe 40 branched from the main steam engine is connected to the upper header, and a DC drive type isolation valve is installed in the middle of the steam supply pipe 40 to isolate the driven secondary condensation system when necessary. The condensate return pipe (70) connected downward from the lower header is connected to the main water supply pipe (23), and the normally driven DC secondary type driven secondary condensing system operating valve (71, 72) closed during normal operation of the power plant. Is installed in the middle of the condensate water supply pipe 70, and is opened when the driven secondary condensation system is operated.

When the driven secondary condensation system is operated, a natural circulation is formed inside the closed secondary condensation system.The driving force of the natural circulation is the difference between the density of water and steam, the level of the steam generator, and the level of the driven secondary condensation system. . Therefore, the passive secondary condensation system must be located at a point sufficiently higher than the steam generator in order to form a smooth natural circulation in the passive secondary condensation system circuit.

When the driven secondary condensation system is operated, the steam generated in the steam generator 20 enters the condenser 60, which is a heat exchanger of the driven secondary condensation system, through the steam supply pipe 40 of the main secondary engine 21 and the driven secondary condensation system circuit. The steam entering the condenser 60 is condensed on the inner wall of the condenser tube due to the temperature difference between the steam temperature and the water in the passive secondary condensing system pool, and the condensate is again passed through the condensate return pipe 70 and the main water supply pipe 23. Return to the economizer.

The heat retained by the steam is transferred by condensation, conduction and boiling to the pool of the driven secondary condenser system via the inner surface of the driven secondary condenser tube and the tube wall, respectively. Due to heat transfer, steam generated in the pool of the driven secondary condensation system tank 50 is discharged to the atmosphere, which is the ultimate heat sink. The amount of water in the passive secondary condensation system tank (50) may be maintained for a certain period of time until the reactor coolant state becomes available for the Shutdown Cooling System (SCS) or until the auxiliary water supply system recovers and performs its function. Sufficient secondary secondary condensation systems are to be available for core residual heat removal and system cooling.

When operating the passive secondary condensation system for core residual heat removal, the total time that the condenser tube inside the passive secondary condensation system tank is submerged in water is 8 hours after system operation and within this time the inlet temperature (176.67 ° C) at which the stationary cooling system can be operated Cool down to). At this time, 8 hours means the time to remove residual heat only by the water inside the passive secondary condensation system tank when there is no additional water supply from any external water source. It is designed to be able to supply and eliminate the residual heat of the core for infinite time.

Therefore, when the system is started, the steam generated by boiling in the steam generator flows into the condenser tube of the driven secondary system and is coagulated while removing residual heat of the reactor coolant, and is recovered to the steam generator as water.

Due to the addition of this facility, the system is simplified and reliability is improved because the active circuit is not used by the natural circulation principle without the need for power when performing the system function. In addition, it is possible to reduce the mental burden on the operator by operating in advance of the feed and bleed operation, and to reduce the possibility of radioactive contamination inside and outside the containment building such as IRWST. It is possible to achieve the effect of reducing the possibility of material release, and the core damage frequency that is directly related to nuclear safety is reduced by 16.7%, which can improve the intrinsic safety of nuclear power plants, possessing and accumulating unique technology to lay the foundation as a developed country of nuclear power plants, and Outstanding effect in terms of public relations about nuclear power plants

Claims (7)

The system is isolated and operated by branching the steam supply pipe from the main steam engine 21, which sends steam to the turbine side from the steam generator 20 generating steam by the heat generated in the reactor 10, passing through the containment outer wall 30. Steam supply pipe 40 for supplying steam to the condenser through a DC drive valve for, A condenser (60) for condensing the steam supplied through the steam supply pipe (40), A secondary secondary condensation tank (50) which deposits the condenser (60) in the cooling water so that condensation can be performed; It comprises a condensate recovery pipe 70 connected to the main water supply pipe through the DC drive valve to recover the condensed water from the condenser 60 to send to the steam generator through the main water supply pipe 23, Passive secondary condensation of a nuclear power plant characterized in that the steam generator can be cooled using a natural circulation principle that requires no power to cool the steam generator when the main water supply system including the water supply pump is unavailable during normal operation and accidents. system. The method of claim 1, wherein the driven secondary condensation tank It is installed outside the containment building outer wall 30, The height of the bottom surface of the driven secondary condensation tank 50, 2. A passive secondary condensation system of a nuclear power plant, characterized in that it is installed at a position higher than the other height of the sum of the steam generator maximum level, the condensate return nozzle height, and the total water level loss at the maximum flow rate. According to claim 1, wherein the steam supply pipe, A steam supply pipe isolation valve 44 for isolating the driven secondary system when the steam supply pipe is broken during system operation; Steam supply pipe valves 41 and 42 designed to prevent steam generator inventory loss due to breakage of the steam supply pipe isolation valve 44; A steam supply pipe bypass valve 43 connected in parallel with the steam supply pipe valves 41 and 42 to preheat and pressurize the condenser in the standby state of the driven secondary condensation system; A loop seal is provided to branch the drain pipe from the steam supply pipe 40 between the steam supply pipe valves 41 and 42 and the steam supply pipe isolation valve 44 to remove condensate formed in the steam supply pipe 40 by heat loss. A drain valve 45; A condenser non-condensable gas exhaust valve installed in an exhaust pipe for discharging non-condensable gas from the steam distributor distributed to the two condensation modules from the top of the condenser 60 to the main steam engine 21 and open in the atmospheric state ( 46) A passive secondary condensation system of a nuclear power plant, characterized in that it is configured to include. According to claim 1, wherein the condensate recovery pipe, A check valve (73) installed to prevent a reverse flow of the driven secondary condensation system due to malfunction of the system atmosphere or opening of the MSSV / MSADV during system operation; A multi-designed condensate return pipe isolation valve (71) (72) for automatically opening the system during operation of the driven secondary condensation system and for isolating the driven secondary system upon breakage of the check valve; The non-condensable gas recovery pipe 80 of the condenser connected in series and in parallel with four DC driving valves to exhaust the non-condensable gas accumulated in the lower header of the condenser 60 into the driven secondary condensation system tank 50. A passive secondary condensation system of a nuclear power plant, characterized in that. The method of claim 1, wherein the passive secondary condensation system, A chemical addition loop (90) for adding a rust inhibitor and purifying treatment to prevent thermal efficiency deterioration due to breeding of organisms in the driven secondary condensation tank (50); A passive secondary condensation system of a nuclear power plant, characterized in that it further comprises a moisture separator 100 for recovering the water back into the tank by recovering the moisture of the vapor / water discharged into the atmosphere from the passive secondary condensation system tank (50) . The method of claim 5, wherein the chemical additive loop, A tank recirculation pump 91 which takes the driven secondary condensing system tank 50 from the inlet 94 installed in the driven secondary condensation tank and pumps it for recirculation; A chemical addition tank (92) for adding a rust preventive agent to the cooling water of the driven secondary condensation tank (50) pumped by the tank recirculation pump (91) to recycle it into the driven secondary condensation tank (50); Periodically inspecting the hydrogen peroxide concentration to deviate from the reference value (50ppm) sample retrieval for sampling between the tank recirculation pump 91 and the chemical addition tank 92 to stop the recirculation pump 91 ( 94); When the recirculation pump 91 is stopped by sampling, the chemicals are injected and supplied to the chemical addition tank 92 to adjust the concentration of the system, and then recycle again to meet the reference value. A chemical addition funnel 95 for introducing chemicals between the chemical addition tanks 92; And a drainage passage 96 configured to drain the water of the system at the rear end of the chemical addition tank 92 to adjust the concentration of the system in relation to the chemical addition and then recycle again to meet the reference value. Passive secondary condensation system of a power plant. The method of claim 1, wherein the passive secondary condensation system, Passive secondary of a nuclear power plant comprising an emergency water suppy (111) and a pure water supply (112) for supplying water into the secondary tank of the driven condensation system Condensation system.