PATENT ABSTRACT
The present invention provides passive safety equipment, comprising: a cooling part formed to cool a first fluid, which is emitted from a reactor coolant system or a steam generator, and a second fluid in a housing; and a circulation induction sprayer which is formed to spray the first fluid emitted from the reactor coolant system or the steam generator into the cooling part, has at least part thereof open to the inside of the housing such that the second fluid flows thereinto according to a drop in pressure caused by the spraying of the first fluid, and sprays the second fluid with the inflown first fluid.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present disclosure relates to a passive safety facility to enhance cooling performance and to reduce radioactive materials within the containment during an accident by introducing a fluid circulation increasing device and filter facility, and a nuclear power plant including the same. 
         [0003]    2. Description of the Related Art 
         [0004]    Reactor is divided into a loop type reactor and an integrated type reactor according to the installation location of main components. When the main components (a steam generator, a pressurizer, a pump, etc.) are installed outside a reactor vessel, it is classified as a loop type reactor (for example, commercial reactor: Korea). When the main components are installed within a reactor vessel, however, it is classified as an integrated type reactor (for example, SMART reactor: Korea). 
         [0005]    Furthermore, reactor is divided into an active type reactor and a passive type reactor according to the implementation method of a safety system. The active type reactor uses an active component such as a pump operated by electric power from an emergency diesel generator or the like to drive the safety system. On the other hand, the passive type reactor uses a passive component operated by passive power such as gravity, gas pressure or the like to drive the safety system. When an accident occurs in the passive type reactor, the passive safety system maintains the reactor in a safe condition for at least a period of time(72 hours) according to the regulatory requirements by using only natural forces integrated in the system even without any operator actions or alternating current (AC) power of a safety class such as an emergency diesel. The operator action or non-safety system involvement is allowable in the passive safety system operation after 72 hours following the design basis accidents. 
         [0006]    In the related art, a passive residual heat removal system and a passive containment cooling system have been configured using a steel containment and a secondary side of a steam generator (Korean Patent Publication No. 10-2013-0047871). However, it is preferable to adopt the reinforced concrete-type containment building rather than the steel containment applied to the related art due to difficulties in manufacturing and maintenance, low economic efficiency, and the like. Hereinafter, a passive residual heat removal system and a passive containment cooling system will be described, respectively. 
         [0007]    The passive residual heat removal system is employed to remove heat in a reactor coolant system (sensible heat in the reactor coolant system and residual heat in the core) during an accident in various reactors including the integrated type reactor. For a cooling water circulation method of the passive residual heat removal system, two types are mainly used, such as a primary fluid circulating method to cool the reactor coolant system (AP1000: United States Westinghouse Company) and a secondary fluid circulating method using a steam generator to cool the reactor coolant system (SMART reactor: Korea), and a method of injecting primary fluid to a condensation tank to directly condensate it (CAREM: Argentina) is also partly used. 
         [0008]    Furthermore, for a cooling method of the heat exchanger (condensation heat exchanger) in the passive residual heat removal system, a water-cooled type (AP1000) that is used most frequently, an air-cooled type (WWER 1000: Russia), and a water-air hybrid cooled type (IMR: Japan) are used. The heat exchanger in the passive residual heat removal system transfers heat received from the reactor coolant system to an outside (ultimate heat sink) through an emergency cooling water storage section or the like. For a method of heat exchanger, a condensation heat exchanger with high heat transfer efficiency using steam condensation phenomenon is mainly used. 
         [0009]    The passive containment cooling system is one of several safety systems for reducing pressure, temperature, and a concentration of radioactive materials. The passive containment cooling system is employed to suppress the increase of pressure and to remove the heat within the containment (reactor building, containment or safeguard vessel) during an accident in various nuclear reactors including the integrated type reactor. For a configuration method of the function of the passive containment cooling system, a method of using a suppression tank for condensing the steam discharged to the containment building (Commercial BWR, CAREM: Argentina, IRIS: United States Westinghouse Company, etc.), a method of applying a steel containment and cooling an outer wall (water spray, air cooling) (AP1000: United States Westinghouse Company), and a method of using a heat exchanger (SWR1000: France Framatome ANP, AHWR: India, SBWR: United States GE), and the like are used. 
         [0010]    As described above, in general, the passive residual heat removal system using the secondary side of the steam generator mainly uses a method of installing a heat sink (emergency cooling water storage section) outside the containment using a natural circulation. The cooling water that is cooled within the condensation heat exchanger is supplied to the steam generator by gravitational force, and the steam that is formed within the steam generator while removing the heat of the reactor coolant system is circulated to the condensation heat exchanger continuously (Korean Patent Publication No. 10-2013-0047871). 
         [0011]    On the other hand, the passive containment cooling system generally uses a method of removing heat within the containment by natural circulation flow formed within the containment without any other flow inducing means. Furthermore, the passive residual heat removal system and passive containment cooling system are typically designed independently. 
         [0012]    The performance of the passive containment cooling system in the related art has been determined only by natural circulation flow without any additional devices for forming the flow thereof. 
         [0013]    In such a configuration where natural convection is dominant, the heat transfer coefficient on a surface over which the atmosphere (air and steam) flows is very small, thereby causing a problem in which the size of the heat exchanger should be greatly increased. Meanwhile, the heat exchanger may be a structure of forming a pressure boundary of the containment, thus a possibility of the pressure boundary break may increase when the size of the heat exchanger increases, thereby causing a problem of decreasing the safety. 
       SUMMARY OF THE INVENTION 
       [0014]    An object of the present disclosure is to propose a passive safety facility with an enhanced cooling performance within the containment using a facility which can overcome the limitation of the natural circulation, and a nuclear power plant including the same. 
         [0015]    Another object of the present disclosure is to provide a passive safety facility capable of performing both functions of a passive residual heat removal system and a passive containment building cooling system, and discharging heat transferred from a reactor coolant system to the external environment, and a nuclear power plant including the same. 
         [0016]    Still another object of the present disclosure is to disclose a passive safety facility capable of enhancing a heat transfer performance without increasing a size of the heat exchanger, and a nuclear power plant including the same. 
         [0017]    Yet still another object of the present disclosure is to disclose a passive safety facility capable of enhancing circulation flow within the containment to reduce a concentration of radioactive materials within the containment at an early stage, and a nuclear power plant including the same. 
         [0018]    Still yet another object of the present disclosure is to provide a passive safety facility capable of collecting radioactive materials to reduce the concentration of the radioactive materials within the containment at an early stage, and a nuclear power plant including the same. 
         [0019]    In order to accomplish an object of the foregoing aspects, a passive safety facility associated with an embodiment of the present disclosure may include a cooling section formed to cool a first fluid discharged from a reactor coolant system or steam generator along with a second fluid within a containment; and a circulation inducing jet device formed to jet the first fluid discharged from the reactor coolant system or the steam generator to the cooling section, at least part of which is open toward an inside of the containment to entrain the second fluid by a pressure drop caused while jetting the first fluid so as to jet the entrained second fluid along with the first fluid. 
         [0020]    The circulation inducing jet device may include a first fluid jetting section connected to the reactor coolant system or the steam generator to receive the first fluid, and formed to jet the received first fluid; a second fluid entraining section formed in an annular shape around the first fluid jetting section to entrain the second fluid within the containment; and a circulating fluid jetting section configured to surround the first fluid jetting section with a portion having an inner diameter larger than that of the first fluid jetting section to form the second fluid entraining section, and supply the first fluid and the second fluid to the cooling section. 
         [0021]    The first fluid jetting section may include a nozzle configured to jet the first fluid to the circulating fluid jetting section, and the circulating fluid jetting section may include a throat formed with an inner diameter smaller than that of an inlet of the nozzle to cause a local pressure drop while jetting the first fluid; and a diffuser configured to induce the first fluid and the second fluid that have passed through the throat to the cooling section. 
         [0022]    The circulation inducing jet device may include a turbine blade rotatably installed at an outlet of the first fluid jetting section to induce the jetting of the first fluid; and a pump impeller connected to the turbine blade to rotate along with the turbine blade, and induce the entrainment of the second fluid through the second fluid entraining section. 
         [0023]    The passive safety facility may further include a filter facility connected to an outlet of the cooling section to filter out noncondensible gas discharged from the cooling section, and collect radioactive materials filtered out from the noncondensible gas. 
         [0024]    The filter facility may include a filter or absorbent configured to separate the radioactive materials from the noncondensible gas; a gas discharge section configured to discharge noncondensible gas filtered out while passing through the filter or absorbent to an inside of the containment; and a gas line connected to the outlet of the cooling section to supply the noncondensible gas to the filter or absorbent. 
         [0025]    The cooling section may cool the first fluid and the second fluid to form condensate, and the passive safety facility may further include a cooling water storage section formed to store cooling water therein, and the cooling water storage section may be installed below the cooling section to collect the condensate discharged from the cooling section. 
         [0026]    The cooling water storage section may include a first cooling water storage section configured to store pure cooling water to be supplied to the steam generator so as to remove sensible heat within the reactor coolant system and residual heat in a core; and a second cooling water storage section configured to store borated water to be injected into the reactor coolant system so as to maintain a level of the reactor coolant system. 
         [0027]    The passive safety facility may further include an additive injection section configured to inject an additive into the condensate for suppressing the revolatilization of condensate collected in the cooling water storage section, and the additive may be formed to maintain a pH of the condensate above a preset value. 
         [0028]    The cooling water storage section may be configured to collect the condensate in the first cooling water storage section, and flow the condensate collected in the first cooling water storage section into the second cooling water storage section when a level of the collected condensate exceeds a reference level, and the additive injection section may be installed at a flow path connected from the first cooling water storage section to the second cooling water storage section to inject the additive into the condensate flowing into the second cooling water storage section. 
         [0029]    The additive injection section may be installed at a flow path connected from the cooling section to the cooling water storage section to inject the additive to condensate collected in the cooling water storage section. 
         [0030]    The passive safety facility may further include a condensate holding section installed between the cooling section and the cooling water storage section to collect the condensate falling from the cooling section so as to return it to the cooling water storage section. 
         [0031]    The passive safety facility may further include a return line extended from an outlet of the cooling section or the condensate holding section to the cooling water storage section to return condensate generated during the cooling process of the cooling section to the cooling water storage section. 
         [0032]    The passive safety facility may further include a filter facility connected to an outlet of the cooling section to filter out noncondensible gas discharged from the cooling section so as to collect radioactive materials filtered out from the noncondensible gas, and the return line may include a first return line connected to a lower portion of the casing to form a flow path of the condensate collected in the casing; and a second return line connected to a lower portion of the filter facility to form a flow path of the condensate collected in the filter facility. 
         [0033]    The passive safety facility may further include a fluid circulation section configured to circulate the cooling water of the cooling water storage section to the circulation inducing jet device through the reactor coolant system or the steam generator, and the fluid circulation section may include a fluid supply line connected to the cooling water storage section to supply cooling water within the cooling water storage section to the reactor coolant system or the steam generator; and a steam discharge line connected to the reactor coolant system or the steam generator and the circulation inducing jet device to supply the first fluid discharged from the reactor coolant system or the steam generator to the circulation inducing jet device. 
         [0034]    The cooling section may include a heat exchanger installed within the containment to allow the cooling water of the emergency cooling water storage section or atmosphere outside the containment to pass therethrough so as to exchange heat with the first fluid and the second fluid jetted from the circulation inducing jet device; and a casing configured to surround the heat exchanger to allow at least part thereof to protect the heat exchanger and accommodate the first fluid and the second fluid jetted from the circulation inducing jet device. 
         [0035]    The connected line may include a first connected line connected to the emergency cooling water storage section and the heat exchanger to form a flow path for supplying the cooling water of the emergency cooling water storage section to the heat exchanger; a second connected line extended from the heat exchanger to an outside of the containment to discharge the cooling water of the emergency cooling water storage section that has passed through the heat exchanger to an outside thereof; a third connected line branched from the second connected line and extended to an outside of the containment to form a flow path for supplying atmosphere outside the containment to the heat exchanger; and a fourth connected line branched from the first connected line and extended to an outside of the containment to discharge atmosphere heated while passing through the heat exchanger to an outside thereof, wherein the passive safety facility further comprises isolation valves installed at the first connected line through the fourth connected line, respectively, and the isolation valves are open or closed by a preset signal to switch between water-cooled type cooling using the coolant and air-cooled type cooling using the atmosphere when the cooling water of the emergency cooling water storage section is exhausted. 
         [0036]    The passive safety facility may further include a filter facility connected to an outlet of the cooling section to filter out noncondensible gas discharged from the cooling section so as to collect radioactive materials filtered out from the noncondensible gas, and the cooling section may include a heat exchanger installed outside the containment to connect to a connected line passing through the containment, and allow the first fluid and the second fluid flowing in from the circulation inducing jet device to pass through the connected line to exchange heat with the cooling water of the emergency cooling water storage section or atmosphere outside the containment, and the filter facility may be installed within the containment, and connected to the heat exchanger by the connected line to receive noncondensible gas and condensate from the heat exchanger. 
         [0037]    The cooling section may include a first heat exchanger installed within the containment to cool the first fluid and second fluid jetted from the circulation inducing jet device; and a second heat exchanger installed outside the containment, and connected to the first heat exchanger by a connected line passing through the containment to form a closed flow path to transfer heat that has transferred to a fluid circulating the closed flow path to cooling water within the emergency cooling water storage section or atmosphere outside the containment. 
         [0038]    The containment may include a containment vessel formed of steel to surround the reactor coolant system; and a containment building formed of concrete to surround the containment vessel at a position separated from the containment vessel to form an air circulating flow path, and the circulation inducing jet device may be configured to jet the first fluid and the second fluid to an inner wall surface of the containment vessel, and the cooling section may cool the containment vessel using air that circulates through the air circulating flow path and the spraying of a passive containment vessel spray system. 
         [0039]    According to the present disclosure having the foregoing configuration, it may be possible to promote natural circulation using a circulation inducing jet device to increase an efficiency of cooling an inside of the containment, thereby overcoming the technical limitation of the related art depending on natural circulation within the containment. 
         [0040]    Furthermore, the present disclosure may induce the second fluid within the containment at the same time to the heat exchanger by the discharge flow of the first fluid, thereby solving the problems of size increase, cost increase and safety degradation in the heat exchanger for cooling the containment in a nuclear power plant. 
         [0041]    In addition, the present disclosure may reduce a concentration of radioactive materials within the containment at an early stage using a filter facility. As the concentration of radioactive materials is reduced, the present disclosure may decrease the exclusion area boundary. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0042]    The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
           [0043]    In the drawings: 
           [0044]      FIG. 1  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility and a nuclear power plant including the same associated with an embodiment of the present disclosure; 
           [0045]      FIG. 2  is an enlarged conceptual view illustrating a circulation inducing jet device illustrated in  FIG. 1 ; 
           [0046]      FIG. 3  is a conceptual view illustrating when an event occurs on a passive safety facility and a nuclear power plant including the same illustrated in  FIG. 1 ; 
           [0047]      FIG. 4  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility and a nuclear power plant including the same associated with another embodiment of the present disclosure; 
           [0048]      FIGS. 5A and 5B  are enlarged conceptual views illustrating a circulation inducing jet device illustrated in  FIG. 4 ; 
           [0049]      FIG. 6  is a conceptual view illustrating when an event occurs on a passive safety facility and a nuclear power plant including the same illustrated in  FIG. 4 ; 
           [0050]      FIG. 7  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility and a nuclear power plant including the same associated with still another embodiment of the present disclosure; 
           [0051]      FIG. 8  is a conceptual view illustrating when an event occurs on a passive safety facility and a nuclear power plant including the same illustrated in  FIG. 7 ; 
           [0052]      FIG. 9  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility and a nuclear power plant including the same associated with yet still another embodiment of the present disclosure; 
           [0053]      FIGS. 10A and 10B  are enlarged conceptual views illustrating a circulation inducing jet device illustrated in  FIG. 9 ; 
           [0054]      FIG. 11  is a conceptual view illustrating when an event occurs on a passive safety facility and a nuclear power plant including the same illustrated in  FIG. 9 ; 
           [0055]      FIG. 12  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with still yet another embodiment of the present disclosure; 
           [0056]      FIG. 13  is a conceptual view illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 12 ; 
           [0057]      FIG. 14  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with yet still another embodiment of the present disclosure; 
           [0058]      FIG. 15  is a conceptual view illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 14 ; 
           [0059]      FIG. 16  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with still yet another embodiment of the present disclosure; 
           [0060]      FIG. 17  is a conceptual view illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 16 ; 
           [0061]      FIG. 18  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with yet still another embodiment of the present disclosure; 
           [0062]      FIG. 19  is a conceptual view illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 18 ; 
           [0063]      FIG. 20  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with still yet another embodiment of the present disclosure; 
           [0064]      FIG. 21  is a conceptual view illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 20 ; 
           [0065]      FIG. 22  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with yet still another embodiment of the present disclosure; 
           [0066]      FIGS. 23 and 24  are conceptual views illustrating when an event occurs on a passive safely system and a nuclear power plant including the same illustrated in  FIG. 22 ; 
           [0067]      FIG. 25  is a conceptual view illustrating when a normal operation is carried out on a passive safely system and a nuclear power plant including the same associated with still yet another embodiment of the present disclosure; 
           [0068]      FIG. 26  is an enlarged conceptual view illustrating part of a passive safely system illustrated in  FIG. 25 ; and 
           [0069]      FIGS. 27 through 29  are conceptual views illustrating a circulation inducing jet device and a modified example thereof. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0070]    Hereinafter, a passive safety facility and a nuclear power plant including the same associated with the present disclosure will be described in more detail with reference to the accompanying drawings. Even in different embodiments according to the present disclosure, the same or similar reference numerals are designated to the same or similar configurations, and the description thereof will be substituted by the earlier description. Unless clearly used otherwise, expressions in the singular number used in the present disclosure may include a plural meaning. 
         [0071]      FIG. 1  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility  1100  and a nuclear power plant  110  including the same associated with an embodiment of the present disclosure. 
         [0072]    The nuclear power plant  110  may include a reactor coolant system  111 , a containment  112  and a passive safety facility  1100 . 
         [0073]    A core  111   a  and a steam generator  111   b  are provided within the reactor coolant system  111 , and a lower portion of the steam generator  111   b  is connected to a feedwater system  113  by a feedwater line  113   a , and an upper portion of the steam generator  111   b  is connected to a turbine system  114  by a steam line  114   a.    
         [0074]    The containment  112  surrounds the reactor coolant system  111  to prevent radioactive materials from being leaked to an external environment. During the occurrence of an accident, such as a loss of coolant accident or non-loss of coolant accident, there is a concern of leaking radioactive materials from the reactor coolant system  111 , and thus the containment  112  is formed to surround the reactor coolant system  111  outside the reactor coolant system  111  to prevent the leakage of radioactive materials. 
         [0075]    The containment  112  performs the role of a final barrier for preventing the leakage of radioactive materials to an external environment from the reactor coolant system  111 . The containment  112  is divided into a containment building (or reactor building) configured with reinforced concrete and a containment vessel and a safeguard vessel configured with a steel vessel according to a material constituting a pressure boundary. The containment vessel is a large vessel designed at a low pressure such as a containment building, and the safeguard vessel is a small vessel designed in a small size at an increased design pressure. According to the present disclosure, unless otherwise noted, the containment  112  commonly refers to a containment building, a reactor building, a containment vessel, a safeguard vessel or the like. The containment  112  illustrated in  FIG. 1  is illustrated as a containment building formed with reinforced concrete. 
         [0076]    Various fluids for maintaining the safety of the nuclear power plant  110  exist within the containment  112 . A fluid for cooling the core  111   a  is filled in the reactor coolant system  111 . Furthermore, fluids for making preparations for various accidents are also filled within the containment  112 . Hereinafter, it will be described that among fluids within the containment  112 , a fluid discharged from the reactor coolant system  111  and a fluid existing in a space between the reactor coolant system  111  and the containment  112  are divided into a first fluid and a second fluid, respectively. However, such a division of fluids is irrelevant to the properties of a fluid or materials constituting a fluid. Accordingly, the first fluid and second fluid may be the same type of fluid. 
         [0077]    The passive safety facility  1100  is configured to circulate a fluid to the reactor coolant system  111  so as to remove the heat of the reactor coolant system  111  using a primary cooling water circulation method or secondary cooling water circulation method, and cool a first fluid discharged from the reactor coolant system  111  and a second fluid within the containment  112  at the same time to discharge heat within the containment  112  to an external environment. The passive safety facility  1100  is configured to increase a heat and pressure reduction efficiency within the containment  112  and a removal efficiency of radioactive materials in a passive method using a structure formed to accelerate circulation flow by getting out of a conventional method using pure natural convection flow that occurs within the containment  112 . 
         [0078]    The passive safety facility  1100  may include a cooling section  1110  and a circulation inducing jet device  1120 . 
         [0079]    The cooling section  1110  is formed to cool a first fluid discharged from the reactor coolant system  111  along with a second fluid within the containment  112 . The cooling section  1110  is configured to discharge heat received from the first fluid and second fluid to an external environment as the first fluid and second fluid are cooled, and return the cooled first fluid and second fluid to a cooling water storage section  1130 . 
         [0080]    The cooling section  1110  may include an emergency cooling water storage section  1111  and a heat exchanger  1112 . 
         [0081]    The emergency cooling water storage section  1111  is formed to store cooling water therein, and receives heat from the first fluid and second fluid, and when the temperature of the cooling water increases, the emergency cooling water storage section  1111  evaporates the cooling water to discharge the received heat to an external environment. At least part of an upper portion of the emergency cooling water storage section  1111  is open to allow cooling water to be evaporated to an external environment. 
         [0082]    The heat exchanger  1112  is installed within the emergency cooling water storage section  1111 , and connected to a connected line  1113  passing through the containment  112  to communicate with an inside of the containment  112 . The heat exchanger  1112  allows a fluid flowing in from the containment  112  through the connected line  1113  to pass therethrough so as to exchange heat with cooling water stored within the emergency cooling water storage section  1111 . A fluid flowing in from the containment  112  through the connected line  1113  may include a first fluid discharged from the reactor coolant system  111  and a second fluid within the containment  112 . According to the characteristics of the nuclear power plant  110 , the cooling section  1110  may be configured with an air-cooled type by exposing the heat exchanger  1112  to atmosphere and installing a duct (not shown) without installing the emergency cooling water storage section  1111 . 
         [0083]    An inlet header  1112   a  for distributing the first fluid and second fluid to an internal flow path of the heat exchanger  1112  is installed at an inlet of the heat exchanger  1112 . An outlet header  1112   b  for collecting heated cooling water from the internal flow path is installed at an outlet of the heat exchanger  1112 . 
         [0084]    The connected line  1113  connects an inside of the containment  112  and the heat exchanger  1112  through the containment  112  and the emergency cooling water storage section  1111 . At least one isolation valve  1114  for closing and isolating the isolation valve  1114  when the system is damaged during an accident or switching at the time point when the maintenance is required may be installed at the connected line  1113 . 
         [0085]    The circulation inducing jet device  1120  is formed to jet the first fluid and second fluid to the cooling section  1110 . The second fluid within the containment  112  is entrained and jetted along with the first fluid by a pressure drop caused while jetting the first fluid. The detailed structure and operation mechanism of the circulation inducing jet device  1120  will be described with reference to  FIG. 2 . 
         [0086]      FIG. 2  is an enlarged conceptual view illustrating the circulation inducing jet device  1120  illustrated in  FIG. 1 . 
         [0087]    The circulation inducing jet device  1120  may include a first fluid jetting section  1121 , a second fluid entraining section  1122   b , and a circulating fluid jetting section  1122 . 
         [0088]    The first fluid jetting section  1121  is connected to the reactor coolant system  111  (refer to  FIG. 1 ) or the steam generator  111   b  to jet a first fluid provided from the reactor coolant system  111  or the steam generator  111   b . The first fluid jetting section  1121  may be connected to the steam generator  111   b  to receive the first fluid from the steam generator  111   b  as illustrated in  FIG. 1 . 
         [0089]    The first fluid jetting section  1121  may include a nozzle  1121   a  formed to jet the first fluid. The first fluid discharged through the nozzle  1121   a  rapidly increases the speed thereof, and decreases the pressure thereof while passing through a throat  1122   a  with a small flow path area. Accordingly, a pressure drop is locally caused within the circulation inducing jet device  1120 . 
         [0090]    The second fluid entraining section  1122   b  is formed in an annular shape around the first fluid jetting section  1121  to entrain the second fluid within the containment. A pressure difference is formed between an inside and an outside of the circulation inducing jet device  1120  by a pressure drop caused by the jetting of the first fluid. Since a pressure within the circulation inducing jet device  1120  is lower than that of the outside thereof, the second fluid existing outside the circulation inducing jet device  1120  is entrained into the circulation inducing jet device  1120  through the second fluid entraining section  1122   b.    
         [0091]    The circulating fluid jetting section  1122  as a portion having an inner diameter larger than that of the first fluid jetting section  1121  to form the second fluid entraining section  1122   b  surrounds the first fluid jetting section  1121 . Accordingly, the second fluid entraining section  1122   b  having an annular shape is formed between an outer circumferential surface of the first fluid jetting section  1121  and an inner circumferential surface of the circulating fluid jetting section  1122 . 
         [0092]    The circulation inducing jet device  1120  supplies the first fluid and second fluid to the cooling section  1110  at the same time. The circulation inducing jet device  1120  may include a throat  1122   a  and a diffuser  1122   c.    
         [0093]    The throat  1122   a  is formed with an inner diameter smaller than that of the surroundings to cause a local pressure drop during the jetting of the first fluid. As illustrated in  FIG. 2 , the throat  1122   a  has an inner diameter smaller than that of the second fluid entraining section  1122   b  and diffuser  1122   c.    
         [0094]    The diffuser  1122   c  naturally induces the first fluid and second fluid to the cooling section  1110  without generating a large pressure loss to the first fluid and second fluid that have passed through the throat  1122   a . If the flowing of the first fluid and second fluid that have passed through the throat  1122   a  is not naturally diffused, a flow path resistance may increase to decrease circulation flow. The diffuser  1122   c  decreases a flow path resistance by naturally changing a dynamic pressure to a static pressure to efficiently supply the first fluid and second fluid to the cooling section  1110 . 
         [0095]    As illustrated in  FIG. 2 , the throat  1122   a  and the diffuser  1122   c  are sequentially connected to each other. The inner diameter thereof is formed to gradually decrease as moving from the second fluid entraining section  1122   b  to the throat  1122   a , and increase again as moving from the throat  1122   a  to the diffuser  1122   c.    
         [0096]    The circulating fluid jetting section  1122  is connected to the connected line  1113  passing through the containment  112 . The circulating fluid jetting section  1122  jets the first fluid and second fluid to an inside of the connected line  1113 . The jetted first fluid and second fluid exchanges heat with cooling water within the emergency cooling water storage section  1111  while passing through the heat exchanger  1112 . 
         [0097]    Due to such a structural feature of the circulation inducing jet device  1120 , the present disclosure may overcome the limitation of the related art depending on pure natural convection within the containment  112 , and promote the circulation flow of the first fluid and second fluid to enhance cooling efficiency within the containment  112 . 
         [0098]    Referring to  FIG. 1  again, the passive safety facility  1100  may include a cooling water storage section  1130 , a fluid circulation section  1140 , a condensate holding section  1150  and a return line  1160 . 
         [0099]    The cooling water storage section  1130  is formed to store cooling water to be injected into the reactor coolant system  111  therein. The cooling water storage section  1130  is installed at a position higher than that of the reactor coolant system  111  to allow the injection of cooling water due to a gravity water head. 
         [0100]    According to the present disclosure, the passive safety system  1110  collectively refers to i) a function of a passive residual heat removal system and ii) a latter safety injection function of a passive safety injection system. The cooling water circulation method of the passive safety system  1110  may use a secondary cooling water circulation method using the steam generator  111   b  and a primary cooling water circulation method for directly injecting cooling water to the reactor coolant system  111 . Cooling water stored in the cooling water storage section  1130  may be used for at least one of the residual heat removal of the reactor coolant system  111  and safety injection to the reactor coolant system  111  according to the usage. 
         [0101]    Since sensible heat and residual heat generated from the core  111   a  exist within the reactor coolant system  111  during the occurrence of an accident, the sensible heat and residual heat should be removed to safely maintain the core  111   a . A method of circulating cooling water to the steam generator  111   b  to remove sensible heat within the reactor coolant system  111  and residual heat in the core  111   a  is applied to the embodiment of  FIG. 1 . The cooling water storage section  1130  may be connected to the feedwater line  113   a  to use cooling water stored therein for the removal of residual heat. 
         [0102]    Furthermore, since a water level of the reactor coolant system  111  decreases during the occurrence of an accident, cooling water should be injected into the reactor coolant system  111  to maintain the water level. The cooling water storage section  1130  may be connected to the safety injection line  115   a  by a line  1115  to use cooling water stored therein for safety injection. 
         [0103]    The cooling water storage section  1130  may be separately provided with a first cooling water storage section  1130   a  and a second cooling water storage section  1130   b  to store pure cooling water to be used for residual heat removal and borated water to be used for safety injection, respectively, in a separate manner as illustrated in  FIG. 1 . 
         [0104]    The first cooling water storage section  1130   a  stores pure cooling water to be supplied to the steam generator  111   b  to remove sensible heat within the reactor coolant system  111  and residual heat in the core  111   a . The second cooling water storage section  1130   b  stores borated water to be directly injected into the reactor coolant system  111  to maintain the water level of the reactor coolant system  111 . 
         [0105]    The fluid circulation section  1140  is formed to circulate the first fluid from the cooling water storage section  1130  to the circulation inducing jet device  1120  through the reactor coolant system  111  or the steam generator  111   b . The fluid circulation section  1140  may include a fluid supply line  1141  and a steam discharge line  1142 . 
         [0106]    The fluid supply line  1141  is connected to the cooling water storage section  1130  to supply cooling water within the cooling water storage section  1130  to the reactor coolant system  111  or steam generator  111   b . The fluid supply line  1141  may be directly or indirectly connected to the reactor coolant system  111 . The fluid supply line  1141  may be connected to the feedwater line  113   a  to supply cooling water to the steam generator  111   b  within the reactor coolant system  111  as illustrated in the drawing. 
         [0107]    The steam discharge line  1142  is connected to the circulation inducing jet device  1120  to supply the first fluid that has passed through the reactor coolant system  111  or steam generator  111   b  to the circulation inducing jet device  1120 . The steam discharge line  1142  may supply is connected to the steam generator  111   b  to supply the first fluid discharged from the steam generator  111   b  to the circulation inducing jet device  1120  as illustrated in the drawing. 
         [0108]    The condensate holding section  1150  collects condensate formed by cooling the first fluid and second fluid in the cooling section  1110 . At least part of an upper portion of the condensate holding section  1150  is open to collect condensate falling from the cooling section  1110  and installed between the cooling section  1110  and the cooling water storage section  1130 . 
         [0109]    The return line  1160  is extended from the condensate holding section  1150  to the cooling water storage section  1130  to return condensate collected in the condensate holding section  1150  again to the cooling water storage section  1130 . A flow regulator  1160   a  for controlling the flow of the condensate may be installed at the return line  1160 . 
         [0110]    When the condensate is collected in the condensate holding section  1150 , and returned to the cooling water storage section  1130  through the return line  1160 , the circulation of flow started from the cooling water storage section  1130  is completed. The present disclosure induces the circulation of flow in a passive method by natural forces, and thus the circulation of flow does not end by one circulation. The circulation of flow may continue to be sustained while a sufficient passive force capable of inducing the circulation of flow within the containment  112  is maintained by generating steam from the reactor coolant system  111  or steam generator  111   b.    
         [0111]    Hereinafter, the operation of the passive safety facility  1100  and the nuclear power plant  110  including the same during the occurrence of an accident will be described. 
         [0112]      FIG. 3  is a conceptual view illustrating when an event occurs on the passive safety facility  1100  and the nuclear power plant  110  including the same illustrated in  FIG. 1 . 
         [0113]    When an accident such as a loss of coolant accident occurs, isolation valves  113   b ,  114   b  installed at the feedwater line  113   a  and steam line  114   a , respectively, are closed. Then, valves  115   b  installed at the safety injection line  115   a  are open to implement safety injection from the safety injection facility  115  to the reactor coolant system  111 . When an internal pressure of the reactor coolant system  111  decreases as the isolation valve  1115   a  and check valve  1115   b  installed at the line  1115  connected to the safety injection line  115   a  are open, borated water stored in the second cooling water storage section  1130   b  is also injected into the reactor coolant system  111  by a gravity water head. The borated water stored in the second cooling water storage section  1130   b  performs the role of maintaining a water level within the reactor coolant system  111  along with the safety injection facility  115 . 
         [0114]    The isolation valve  1141   a  and check valve  1141   b  installed at the fluid supply line  1141  for connecting the first cooling water storage section  1130   a  to the feedwater line  113   a  are also open to start the supply of cooling water due to a gravity water head. The cooling water of the first cooling water storage section  1130   a  is supplied to a lower portion of the steam generator  111   b  through the feedwater line  113   a  to remove sensible heat within the reactor coolant system  111  and residual heat in the core  111   a  in the steam generator  111   b , and is discharged to an upper portion of the steam generator  111   b.    
         [0115]    The isolation valve  1142   a  installed at the steam discharge line  1142  is also open, and the first fluid discharged to an upper portion of the steam generator  111   b  is evaporated through the steam discharge line  1142 . The first fluid is supplied to the circulation inducing jet device  1120 , and the circulation inducing jet device  1120  jets the first fluid supplied through the steam discharge line  1142  and the second fluid entrained from an inside of the containment  112  by a pressure drop to the connected line  1113 . 
         [0116]    The first fluid and second fluid jetted from the circulation inducing jet device  1120  transfer heat cooling water within the emergency cooling water storage section  1111  while passing through the heat exchanger  1112 , and cool and condense. The cooling water within the emergency cooling water storage section  1111  evaporates and discharges heat to an external environment when the temperature increases. 
         [0117]    The condensate formed by cooling and condensing the first fluid and second fluid in the heat exchanger  1112  is injected into the containment  112  again through the connected line  1113 , and collected into the condensate holding section  1150  installed at a lower portion of the connected line  1113 . Noncondensible gas discharged along with condensate from the connected line  1113  is discharged into the containment  112 . The condensate collected in the condensate holding section  1150  is returned to the cooling water storage section  1130  again through the return line  1160 , and the circulation of flow is carried out in a continuous and consistent manner. However, when it is configured to directly collect condensate into the cooling water storage section  1130  according to the characteristics of the nuclear power plant  110 , the condensate holding section  1150  may not be separately provided therein. 
         [0118]    Hereinafter, another embodiment of a passive safety facility and a nuclear power plant including the same will be described. 
         [0119]      FIG. 4  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility  1200  and a nuclear power plant  120  including the same associated with another embodiment of the present disclosure. 
         [0120]    The passive safety facility  1200  may include a cooling section  1210  and a circulation inducing jet device  1220 . 
         [0121]    The passive safety facility  1200  may include a cooling section  1210  and a circulation inducing jet device  1220 . 
         [0122]    An emergency cooling water storage section  1211  is installed outside the containment  122 , and cooling water is stored therein. A heat exchanger  1212  is installed within the containment  122  other than an inside of the emergency cooling water storage section  1211 , and connected to the emergency cooling water storage section  1211  by a connected line  1213  passing through the containment  122 . A sparger  1213 ′ for jetting cooling water may be installed at an end portion of the connected line  1213 . The heat exchanger  1212  is configured to allow cooling water within the emergency cooling water storage section  1211  to pass therethrough so as to exchange heat with the first fluid and second fluid jetted from the circulation inducing jet device  1220 . However, a duct (not shown) may be installed to configure the nuclear power plant  120  in an air-cooled type without installing the emergency cooling water storage section  1211  according to the characteristics of the nuclear power plant  120 . 
         [0123]    The structure and operation of the circulation inducing jet device  1220  illustrated in  FIG. 4  will be described with reference to  FIGS. 5A and 5B . 
         [0124]      FIGS. 5A and 5B  are enlarged conceptual views illustrating the circulation inducing jet device  1220  illustrated in  FIG. 4 .  FIG. 5A  is a conceptual view in which the circulation inducing jet device  1220  is seen from a front side, and  FIG. 5B  is a conceptual view in which the circulation inducing jet device  1220  is seen from a lateral side. 
         [0125]    A circulating fluid jetting section  1222  jets the first fluid and second fluid to the heat exchanger  1212 . The jetted first fluid and second fluid exchange heat with cooling water in the heat exchanger  1212 . 
         [0126]    An inlet header  1212   a  for distributing cooling water supplied from the emergency cooling water storage section  1211  (refer to  FIG. 4 ) to an internal flow path of the heat exchanger  1212  is installed at an inlet of the heat exchanger  1212 . An outlet header  1212   b  for collecting heated cooling water from the internal flow path is installed at an outlet of the heat exchanger  1212 . A tube  1212   c  is installed between the inlet header  1212   a  and the outlet header  1212   b . A casing  1215  for protecting the tube  1212   c  from missiles (fragments) during an accident is installed on a circumference of the tube  1212   c.    
         [0127]    The circulation inducing jet device  1220  is formed to jet the first fluid and second fluid to a surface of the heat exchanger  1212 . However, when a shell-and-tube type heat exchanger is employed according to the design characteristics of the nuclear power plant  120 , shell and tube side flow paths may be configured in an opposite manner. The first fluid and second fluid jetted from the circulation inducing jet device  1220  are cooled and condensed by exchanging heat with the cooling water of the emergency cooling water storage section  1211  while passing through the internal flow path of the heat exchanger  1212 . 
         [0128]    Referring to  FIG. 4  again, the passive safety facility  1200  may include a cooling water storage section  1230 ′,  1230 ″. 
         [0129]    The cooling water storage section  1230 ′,  1230 ″ may be formed with a tank or cistern in which a first cooling water storage section and a second cooling water storage section are integrally formed without including the first cooling water storage section and the second cooling water storage section in a separate manner. A plurality of cooling water storage sections  1230 ′,  1230 ″ may be provided therein, and any part of the cooling water storage section  1230 ′ may be connected to the feedwater line  123   a , and another part of the cooling water storage section  1230 ″ may be connected to the safety injection line  125   a.    
         [0130]    Hereinafter, the operation of the passive safety facility  1200  and the nuclear power plant  120  including the same as illustrated in  FIG. 4  during the occurrence of an accident will be described. 
         [0131]      FIG. 6  is a conceptual view illustrating when an event occurs on the passive safety facility  1200  and the nuclear power plant  120  including the same illustrated in  FIG. 4 . 
         [0132]    When an accident occurs on the nuclear power plant  120 , isolation valves  123   b ,  124   b  installed at the feedwater line  123   a  and steam line  124   a , respectively, are closed. Then, an isolation valve  1241   a  and a check valve  1241   b  installed at a fluid supply line  1241  are open. An isolation valve  1215   a  and a check valve  1251   b  installed at a line  1215  for connecting between a cooling water storage section  1230 ″ and a safety injection line  125   a  are also open. 
         [0133]    The cooling water of the cooling water storage section  1230 ″ is safely injected into a reactor coolant system  121  along with the cooling water of the safety injection facility  125 . The cooling water of the cooling water storage section  1230 ′ is supplied to a steam generator  121   b  through the fluid supply line  1241  to remove sensible heat within the reactor coolant system  121  and residual heat in the core  121   a.    
         [0134]    The first fluid discharged from the steam generator  121   b  is evaporated through a steam discharge line  1242  in which an isolation valve  1242   a  is open, and supplied to the circulation inducing jet device  1220 . The first fluid is jetted to the heat exchanger  1212  by the circulation inducing jet device  1220 . The second fluid is also entrained into the circulation inducing jet device  1220  and jetted to the heat exchanger  1212  along with the first fluid. The first fluid and second fluid exchange heat with cooling water supplied from the emergency cooling water storage section  1211  on a surface of the heat exchanger  1212 , and cool and condense. Then, condensate formed by condensing the first fluid and second fluid falls by gravity. 
         [0135]    The falling condensate is collected into a condensate holding section  1250 , and returned to the cooling water storage section  1230  through a return line  1260 , and the circulation of flow is consistently carried out. 
         [0136]    Hereinafter, still another embodiment of a passive safety facility and a nuclear power plant including the same will be described. 
         [0137]      FIG. 7  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility  1300  and a nuclear power plant  130  including the same associated with still another embodiment of the present disclosure. 
         [0138]    The passive safety facility  1300  may include a cooling section  1310  and a circulation inducing jet device  1320 . 
         [0139]    The passive safety facility  1300  may include an emergency cooling water storage section  1311 , a first heat exchanger  1312 ′ and a second heat exchanger  1312 ″. 
         [0140]    The description of the emergency cooling water storage section  1311  will be substituted by the earlier description of  FIGS. 1 and 4 . 
         [0141]    The heat exchanger  1312 ′ is installed within a containment  132  to exchange heat a fluid within the containment  132 . 
         [0142]    The second heat exchanger  1312 ″ is installed within the emergency cooling water storage section  1311 , and connected to the first heat exchanger  1312 ′ by a connected line  1313  to form a closed flow path with the second heat exchanger  1312 ″. A fluid circulates within the closed flow path independently from cooling water within the emergency cooling water storage section  1311  or a fluid within the containment  132 . The second heat exchanger  1312 ″ transfers heat transferred to a fluid that circulates the closed flow path in the first heat exchanger  1312 ′ to cooling water within the emergency cooling water storage section  1311 . The heat transferred to the emergency cooling water storage section  1311  is discharged to an external environment by the evaporation of cooling water. 
         [0143]    The connected line  1313  is connected to the first heat exchanger  1312 ′ and the second heat exchanger  1312 ″, respectively, through the containment  132  and emergency cooling water storage section  1311 . A makeup tank  1316  is formed to store a makeup fluid therein, and connected to the connected line  1313  to make up the makeup fluid to the closed flow path. 
         [0144]    A first cooling water storage section  1330   a  may be used for the purpose of removing sensible heat within a reactor coolant system  131  and residual heat in a core  131   a , and a safety injection facility (not shown) may be separately provided from the first cooling water storage section  1330   a.    
         [0145]      FIG. 8  is a conceptual view illustrating when an event occurs on a passive safety facility  1300  and a nuclear power plant  130  including the same illustrated in  FIG. 7 . 
         [0146]    When an accident occurs on the nuclear power plant  130 , isolation valves  133   b ,  134   b  installed at the feedwater line  133   a  and steam line  134   a , respectively, are closed. 
         [0147]    Furthermore, an isolation valve  1341   a  and a check valve  1341   b  installed at the fluid supply line  1341  are open to supply cooling water to a steam generator  131   b . Cooling water supplied to the steam generator  131   b  is evaporated by receiving sensible heat and residual heat. The first fluid discharged from the steam generator  131   b  is supplied to the circulation inducing jet device  1320  through the steam discharge line  1342 . 
         [0148]    The circulation inducing jet device  1320  jets the first fluid supplied through the steam discharge line  1342  and the second fluid entrained from the containment  132  to a surface of the first heat exchanger  1312 ′. The first fluid and second fluid jetted to a surface of the first heat exchanger  1312 ′ exchange heat with cooling water flowing through an inside of the closed flow path formed by the first heat exchanger  1312 ′, the second heat exchanger  1312 ″ and the connected line  1313  to cool and condense, and falls as condensate. The falling condensate is collected into a condensate holding section  1350 . 
         [0149]    A fluid flowing through an inside of the closed flow path receives heat from an inside of the containment  132  while persistently circulating the closed flow path, and transfers the received heat to cooling water within an emergency cooling water storage section  1311 . When a fluid within the closed flow path is insufficient, a makeup fluid is made up from the makeup tank  1316  to continue the circulation. Cooling water within the emergency cooling water storage section  1311  increases the temperature as receiving heat, and evaporates to discharge heat to an external environment. 
         [0150]    Hereinafter, a passive safety facility  1400  and a nuclear power plant  140  including the same according to yet still another embodiment of the present disclosure will be described. 
         [0151]      FIG. 9  is a conceptual view illustrating when a normal operation is carried out on a passive safety facility  1400  and a nuclear power plant  140  including the same associated with yet still another embodiment of the present disclosure. 
         [0152]    The nuclear power plant  140  may include a reactor coolant system  141 , a containment  142 , a passive containment vessel spray system  146 , and a passive safety facility  1400 . 
         [0153]    The containment  142  may include a containment vessel  142   a  and a containment building  142   b  contrary to the foregoing containment. 
         [0154]    The containment vessel  142   a  formed of steel, and formed to surround the reactor coolant system  141 . The containment building  142   b  is formed of concrete, and formed to surround the containment vessel  142   a  at a position separated from the containment vessel  142   a  so as to form an air circulation flow path  142   c  between the containment vessel  142   a  and the containment building  142   b . The containment building  142   b  may include at least one air inlet  142   b ′ to flow external air for cooling the containment vessel  142   a  thereinto while circulating the air circulation flow path  142   c.    
         [0155]    The passive containment vessel spray system  146  may include a spray cooling water storage section  146   a , a spray line  146   b , a spray isolation valve  146   c  and a spray nozzle  146   d.    
         [0156]    The spray cooling water storage section  146   a  is formed to store cooling water, and installed at an upper portion of the containment building  142   b . The spray line  146   b  may form a flow path to flow the cooling water of the spray cooling water storage section  146   a , and the spray isolation valve  146   c  may be installed at the spray line  146   b . Furthermore, the spray nozzle  146   d  may be installed at an end portion of the spray line  146   b . The passive containment vessel spray system  146  sprays cooling water to an outer surface of the containment vessel  142   a  to cool the containment vessel  142   a.    
         [0157]    The passive safety facility  1400  may include a cooling water storage section  1430  and a circulation inducing jet device  1420 . 
         [0158]    The cooling water storage section  1430  may include a first cooling water storage section  1430   a  and a second cooling water storage section  1430   b.    
         [0159]    The first cooling water storage section  1430   a  is connected to a feedwater line  143   a  to inject cooling water into a steam generator  141   b . The first fluid discharged from the steam generator  141   b  is supplied to the circulation inducing jet device  1420  through a steam discharge line  1442 . 
         [0160]    The second cooling water storage section  1430   b  is connected to a safety injection line  145   a  to inject borated water into the reactor coolant system  141 . Cooling water safely injected from the second cooling water storage section  1430   b  circulates the reactor coolant system  141 , and the first fluid discharged from the reactor coolant system  141  is supplied to the circulation inducing jet device  1420  through the steam discharge line  1442 . 
         [0161]    The circulation inducing jet device  1420  will be described with reference to  FIGS. 10A and 10B . 
         [0162]      FIGS. 10A and 10B  are enlarged conceptual views illustrating the circulation inducing jet device  1420  illustrated in  FIG. 9 .  FIG. 10A  is a conceptual view in which the circulation inducing jet device  1420  is seen from a front side, and  FIG. 10B  is a conceptual view in which the circulation inducing jet device  1420  is seen from a lateral side. 
         [0163]    The circulation inducing jet device  1420  is formed to jet the first fluid and the second fluid to an inner wall surface of the containment vessel  142   a . An outlet of the circulation inducing jet device  1420  is installed toward an inner wall surface of the containment vessel  142   a.    
         [0164]    The first fluid supplied from the steam discharge line  1442  (refer to  FIG. 9 ) is jetted from a first fluid jetting section  1421 . The second fluid is also entrained into the circulation inducing jet device  1420 . The first fluid and second fluid is jetted to an inner wall surface of the containment vessel  142   a . The first fluid and second fluid jetted to the containment vessel  142   a  are cooled and condensed on the inner wall surface of the containment vessel  142   a.    
         [0165]    Referring to  FIG. 9  again, the cooling section is not installed as an additional device on the nuclear power plant  140 , but the containment vessel  142   a  functions as the cooling section. The first fluid and second fluid jetted from the circulation inducing jet device  1120  transfer heat to the containment vessel  142   a . Air that circulates the air circulation flow path  142   c  through the air inlet  142   b ′ and cooling water sprayed from the passive containment vessel spray system  146  consistently cool the containment vessel  142   a . Heat is discharged to an external environment by air that circulates the air circulation flow path  142   c  and cooling water sprayed on an outer surface of the containment vessel  142   a.    
         [0166]    A condensate holding section  1450  is installed at a lower portion of an outlet of the circulation inducing jet device to collect condensate condensed on an inner wall surface of the containment vessel  142   a  to fall. 
         [0167]    On the contrary, the cooling water storage section  1430  may be also installed at a lower portion of an outlet of the circulation inducing jet device  1420  on the nuclear power plant  140  without installing the condensate holding section  1450  in a separate manner to collect condensate condensed on the inner wall surface of the containment vessel  142   a  to fall. 
         [0168]    Hereinafter, the operation of the passive safety facility  1400  and the nuclear power plant  140  including the same as illustrated in  FIG. 9  during the occurrence of an accident will be described. 
         [0169]      FIG. 11  is a conceptual view illustrating when an event occurs on the passive safety facility  1400  and the nuclear power plant  140  including the same illustrated in  FIG. 9 . 
         [0170]    When an accident occurs on the nuclear power plant  140 , isolation valves  143   b ,  144   b  installed at the feedwater line  143   a  and steam line  144   a , respectively, are closed. An isolation valve  145   b  installed at a safety injection line  145   a  for connecting between the safety injection facility  145  and the reactor coolant system  141  are open. An isolation valve  1415   a  and a check valve  1451   b  installed at a line  1415  for connecting between a safety injection line  145   a  and a second cooling water storage section  1430   b  are also open. When a pressure within the reactor coolant system  141  decreases, safety injection from the safety injection facility  145  or the second cooling water storage section  1430   b  into the reactor coolant system  141  is carried out by a gravity water head. 
         [0171]    The first fluid that has received heat within the reactor coolant system  141  is evaporated through the steam discharge line  1442 , and jetted to an inner wall surface of the containment vessel  142   a  along with the second fluid through the circulation inducing jet device  1420 . Accordingly, heat is transferred from the first fluid and second fluid to the containment vessel  142   a.    
         [0172]    External air flows on an outer surface of the containment vessel  142   a  through the air inlet  142 ′ to cool the containment vessel  142   a  while circulating the air circulation flow path  142   c . The air that has received heat from the outer surface of the containment vessel  142   a  is ascended and discharged to an outside through an opening portion at an upper portion of the containment building  142   b . Furthermore, the passive containment vessel spray system  146  sprays cooling water to an outer surface of the containment vessel  142   a  to cool the containment vessel  142   a  as the spray isolation valve  146   c  is open. The containment vessel  142   a  is cooled by air circulation and spraying. As the circulation inducing jet device  1420  sprays the first fluid and second fluid to the containment vessel  142   a , heat transferred to the containment vessel  142   a  may be discharged to an external environment by air circulation and spraying. 
         [0173]    Condensate formed by cooling and condensing the first fluid and second fluid on an inner wall surface of the containment vessel  142   a  falls, and returns to the cooling water storage section  1430  through the condensate holding section  1450 . 
         [0174]    According to the foregoing embodiments, noncondensible gas is discharged to an inside of the containment. Hereinafter, a passive safety facility including a filter facility for filtering out noncondensible gas and a nuclear power plant including the same will be described. 
         [0175]      FIG. 12  is a conceptual view illustrating a passive safely system  2100  and a nuclear power plant  210  including the same associated with still yet another embodiment of the present disclosure. 
         [0176]    The nuclear power plant  210  may include a containment  212 , a reactor coolant system  211 , a core  211   a , a steam generator  211   b , a reactor coolant pump  211   c  and a pressurizer  211   d . The nuclear power plant  210  may include systems for the normal operation of the nuclear power plant  210  and various systems for securing the safety of the nuclear power plant  210  in addition to the constituent elements illustrated in  FIG. 12 . 
         [0177]    The reactor coolant system  211  is installed within the containment  212 . The reactor coolant system  211  is a coolant system for transferring and transporting thermal energy generated by the fission of the core  211   a . The first fluid is filled into the reactor coolant system  211 . During the occurrence of an accident such as a loss of coolant accident, steam may be discharged from the reactor coolant system  211 , and the containment  212  blocks radioactive materials contained in the steam from being leaked to an outside thereof. 
         [0178]    The steam generator  211   b  generates steam using heat transferred from the core. A lower inlet of the steam generator  211   b  is connected to a feedwater system  213  by a feedwater line  213   a , and an upper outlet of the steam generator  211   b  is connected to a turbine system  214  by a steam line  214   a . Feedwater supplied to the steam generator  211   b  through the feedwater line  213   a  evaporates in the steam generator  211   b  to become steam. The steam is supplied to the turbine system  214  through the steam line  214   a.    
         [0179]    The reactor coolant pump  211   c  induces the circulation of the first fluid, and the pressurizer  211   d  maintains a pressurized state that exceeds a saturation pressure to prevent the boiling of coolant in the core  211   a  of a pressurized water reactor. 
         [0180]    The containment  212  surrounds the reactor coolant system  211  to prevent radioactive materials from being leaked to an external environment. During the occurrence of an accident, such as a loss of coolant accident or non-loss of coolant accident, there is a concern of leaking radioactive materials from the reactor coolant system  211 , and thus the containment  212  is formed to surround the reactor coolant system  211  at an outside of the reactor coolant system  211  to prevent the leakage of radioactive materials. 
         [0181]    Various fluids for maintaining the safety of the nuclear power plant  210  exist within the containment  212 . A fluid for cooling the core  211   a  is filled in the reactor coolant system  211 . Furthermore, fluids for making preparations for various accidents are also filled within the containment  212 . Hereinafter, it will be described that among fluids within the containment  212 , a fluid discharged from the reactor coolant system  211  and a fluid existing in a space between the reactor coolant system  211  and the containment  212  are divided into a first fluid and a second fluid, respectively. However, such a division of fluids is irrelevant to the properties of a fluid or materials constituting a fluid. Accordingly, the first fluid and second fluid may be the same type of fluid. Furthermore, the first fluid and second fluid should be distinguished from a primary fluid and a secondary fluid. The primary fluid and the secondary fluid may be a first fluid or second fluid. 
         [0182]    Referring to  FIG. 12 , a method of circulating the second fluid using the steam generator  211   b  is applied to the passive safely system  2100 . Accordingly, both the first fluid and second fluid in the passive safely system  2100  illustrated in  FIG. 12  indicate a secondary fluid. If it is a passive safety facility with a method of circulating the first fluid, then both the first fluid and second fluid indicate a primary fluid. 
         [0183]    The passive safely system  2100  removes the sensible heat of the reactor coolant system  211  and the residual heat of the core  211   a  using a circulation method of the primary fluid or a circulation method of the secondary fluid. In case of using the circulation of the primary fluid, the passive safely system  2100  circulates the primary fluid to the reactor coolant system  211 . In case of using the circulation of the secondary fluid, the passive safely system  2100  circulates the secondary fluid to the steam generator  211   b.    
         [0184]    The passive safely system  2100  is configured to cool the first fluid discharged from the reactor coolant system  211  or steam generator  211   b  and the second fluid within the containment  212  at the same time to discharge heat within the containment  212  to an external environment.  FIG. 12  illustrates the passive safely system  2100  using the circulation method of the secondary fluid. 
         [0185]    The passive safety facility  2100  uses a facility formed to accelerate circulation flow by getting out of a conventional method using pure natural convection flow. The passive safely system  2100  is configured to increase a heat and pressure reduction efficiency within the containment  212  and a removal efficiency of radioactive materials in a passive method. 
         [0186]    Referring to  FIG. 12 , the passive safely system  2100  may include a cooling section  2110 , a circulation inducing jet device  2120  and a filter facility  2170 . 
         [0187]    The cooling section  2110  is formed to cool the first fluid discharged from the steam generator  211   b  along with the second fluid within the containment  212 . The cooling section  2110  is configured to discharge heat received from the first fluid and second fluid to an external environment of the containment  212  as the first fluid and second fluid are cooled. 
         [0188]    The cooling section  2110  may include an emergency cooling water storage section  2111 , a heat exchanger  2112 , a connected line  2113  and an isolation valve  2114 . 
         [0189]    The emergency cooling water storage section  2111  is formed to store cooling water therein. The cooling water filled in the emergency cooling water storage section  2111  receives heat from the first fluid and second fluid by the heat exchanger  2112 . When the temperature of the cooling water filled in the emergency cooling water storage section  2111  increases, the cooling water evaporates to discharge heat that has transferred to the cooling water to an external environment. At least part of an upper portion of the emergency cooling water storage section  2111  is open to allow cooling water to be evaporated to an external environment. 
         [0190]    The heat exchanger  2112  is configured such that the cooling section of the emergency cooling water storage section  2111  exchanges heat with the first fluid and second fluid. The heat exchanger  2112  may be installed within the containment  212 , and connected to the emergency cooling water storage section  2111  by the connected line  2113  passing through the containment  212 . The heat exchanger  2112  allows cooling water flowing in from the emergency cooling water storage section  2111  through the connected line  2113  to pass therethrough to cool the first fluid and second fluid. 
         [0191]    An inlet header  2112   a  for distributing cooling water supplied from the emergency cooling water storage section  2111  to an internal flow path of the heat exchanger  2112  is installed at an inlet of the heat exchanger  2112 . An outlet header  2112   b  for collecting heated cooling water from the internal flow path of the heat exchanger  2112  is installed at an outlet of the heat exchanger  2112 . 
         [0192]    The connected line  2113  is connected to the heat exchanger  2112  and emergency cooling water storage section  2111  to form a circulating flow path of cooling water stored in the emergency cooling water storage section  2111 . A plurality of connected lines  2113  are provided therein and connected to the inlet header  2112   a  and outlet header  2112   b , respectively, of the heat exchanger  2112 . The connected line  2113  passes through at least part of the containment  212 , and extended to an inside of the emergency cooling water storage section  2111 . 
         [0193]    A sparger  2113 ′ for jetting cooling water may be installed at an end portion of the connected line  2113 . Cooling water returned from the heat exchanger  2112  to the emergency cooling water storage section  2111  by the connected line  2113  may be jetted to an inside of the emergency cooling water storage section  2111  by the sparger  2113 ′. 
         [0194]    The isolation valve  2114  may be installed at each connected line  2113 . The isolation valve  2114  may be closed and isolated when the system is damaged during an accident or switched for maintenance at the time point when the maintenance is required. 
         [0195]    The cooling section  2110  may be divided according to the operation mechanism of the emergency cooling water storage section  2111  and heat exchanger  2112 . As illustrated in  FIG. 12 , the cooling section  2110  in such a type that the heat exchanger  2112  is connected to the emergency cooling water storage section  2111  by the connected line  2113 , and the cooling water of the emergency cooling water storage section  2111  consistently circulates the heat exchanger  2112  may be divided into a circulation type. The cooling section  2110  with a circulation type uses natural circulation based on a density difference due to a difference between cooling water temperatures or phases. 
         [0196]    The cooling section  2110  may be also divided into an immersion type or injection type in addition to the circulation type, and the configuration of the immersion type and injection type will be described later. 
         [0197]    The circulation inducing jet device  2120  is formed to jet the first fluid discharged from the reactor coolant system  211  or steam generator  211   b  to the cooling section  2110 . When the first fluid is jetted, a pressure drop is locally caused in the circulation inducing jet device  2120 . At least part of the circulation inducing jet device  2120  is open toward an inside of the containment  212  to entrain the second fluid by a pressure drop caused while jetting the first fluid. The circulation inducing jet device  2120  jets the entrained second fluid along with the first fluid to the cooling section  2110 . The detailed structure and operation mechanism of the circulation inducing jet device  2120  will be substituted by the earlier description. 
         [0198]    The circulation inducing jet device  2120  jets the first fluid and second fluid to the heat exchanger  2112 . The jetted first fluid and second fluid exchange heat with cooling water in the heat exchanger  2112 . 
         [0199]    An inlet header  2112   a  for distributing cooling water supplied from the emergency cooling water storage section  2111  to an internal flow path of the heat exchanger  2112  is installed at an inlet of the heat exchanger  2112 . An outlet header  2112   b  for collecting heated cooling water from the internal flow path is installed at an outlet of the heat exchanger  2112 . A casing  2115  for protecting the heat exchanger  2112  from missiles (fragments) during an accident is installed on a circumference of the heat exchanger  2112 . 
         [0200]    The circulation inducing jet device  2120  is formed to jet the first fluid and second fluid to a surface of the heat exchanger  2112 . However, when a shell-and-tube type heat exchanger is employed according to the design characteristics of the nuclear power plant  210 , shell and tube side flow paths may be configured in an opposite manner. The first fluid and second fluid jetted from the circulation inducing jet device  2120  are cooled and condensed on a surface of the heat exchanger  2112  by exchanging heat with the cooling water passing through the internal flow path of the heat exchanger  2112 . 
         [0201]    Due to such a structural feature of the circulation inducing jet device  2120 , the present disclosure may overcome the limitation of the related art depending on pure natural convection within the containment  212 , and promote the circulation flow of the first fluid and second fluid to enhance cooling efficiency within the containment  212 . 
         [0202]    The casing  2115  surrounds the heat exchanger  2112  to protect the heat exchanger  2112 . Furthermore, the casing  2115  is configured to accommodate the first fluid and second fluid jetted from the circulation inducing jet device  2120 . 
         [0203]    An upper portion  2115   a  of the casing  2115  is connected to the circulation inducing jet device  2120 . A lower portion  2115   b  of the casing  2115  is sealed excluding a gas line  2173  and a return line  2160 . An intermediate portion  2115   c  connecting between the upper portion  2115   a  and the lower portion  2115   b  surrounds the heat exchanger  2112 . Condensate formed by cooling the first fluid and second fluid may be collected into the lower portion  2115   b  of the casing  2115 . 
         [0204]    The filter facility  2170  is connected to an outlet of the cooling section  2110  to filter out noncondensible gas discharged from the cooling section  2110 . In the passive safely system  2100  illustrated in  FIG. 12 , the outlet of the cooling section  2110  refers to the lower portion  2115   b  of the casing  2115 . The filter facility  2170  collects radioactive materials filtered out from the noncondensible gas. 
         [0205]    The filter facility  2170  may include a filter or absorbent  2171 , and a gas discharge section  2172  and a gas line  2173 . 
         [0206]    The filter or absorbent  2171  is configured to separate the radioactive materials from the noncondensible gas. 
         [0207]    The filter may use a high efficiency particulate air filter (2HEPA filter). Radioactive materials in a gas phase contained in the noncondensible gas are removed while passing through the filter. For example, when the radioactive material is iodine, the iodine is combined with silver nitrate (2silver nitrate) and converted to iodic silver while passing through the filter. Iodic silver is a form that is separable from noncondensible gas. The filter is configured to form iodic silver by reacting silver nitrate with iodine contained in noncondensible gas. Furthermore, the filter is formed to remove iodic silver from the fluid. 
         [0208]    The absorbent may use charcoal. Iodine organic compounds are combined with materials impregnated into charcoal and converted to a form of quaternary ammonium salt, and adsorbed into the charcoal. Iodine in a molecular form is combined with charcoal through chemical absorption. Charcoal is used as an absorbent material since it has a large internal contact area due to its porous structure. Accordingly, the absorbent is formed to remove iodine contained in noncondensible gas through chemical absorption that is carried out by charcoal. 
         [0209]    However, the foregoing filter and absorbent are merely an example, and the types of the filter and absorbent may not be necessarily limited to them. 
         [0210]    The gas discharge section  2172  is configured to discharge noncondensible gas filtered out while passing through the filter or absorbent  2171  to an inside of the containment  212 . Radioactive materials are mostly collected by the filter or absorbent  2171 , and thus there hardly exist radioactive materials in noncondensible gas discharged from the gas discharge section  2172 . 
         [0211]    The gas line  2173  is connected to the outlet of the cooling section  2110  to supply the noncondensible gas to the filter or absorbent  2171 . As illustrated in  FIG. 12 , the gas line may be connected to the lower portion  2115   b  of the casing  2115 . 
         [0212]    The passive safely system  2100  may further include a cooling water storage section  2130 , a fluid circulation section  2140 , a return line  2160  and an additive injection section  2180 . 
         [0213]    The cooling water storage section  2130  is formed to store cooling water to be injected into the reactor coolant system  211  or steam generator  211   b  therein. The cooling water storage section may be installed below cooling water to collect condensate collected into the lower portion  2115   b  of the casing  2115 . The cooling water storage section  2130  may be installed at a position higher than that of the reactor coolant system  211  or steam generator  211   b  to allow the injection of cooling water due to a gravity water head. 
         [0214]    The cooling water stored in the cooling water storage section  2130  may be used for the purpose of removing sensible heat within the reactor coolant system  211  and residual heat in the core  211   a  according to the design. Furthermore, the cooling water stored in the cooling water storage section  2130  may be used for the purpose of being injected into the reactor coolant system  211 . 
         [0215]    Since sensible heat and residual heat generated from the core  111   a  exist within the reactor coolant system  211  during the occurrence of an accident, the sensible heat and residual heat should be removed to safely maintain the core  211   a . A method of circulating cooling water to the steam generator  211   b  to remove sensible heat and residual heat is applied to the present embodiment. The cooling water storage section  2130  may be connected to the feedwater line  213   a  to use cooling water stored therein for the removal of residual heat. The cooling water storage section  2130  illustrated in the right side of the  FIG. 12  will be referred to such a structure. 
         [0216]    Furthermore, since a water level of the reactor coolant system  211  decreases during the occurrence of an accident such as a loss of coolant accident, cooling water should be injected into the reactor coolant system  211  to maintain the water level. The cooling water storage section  2130  may be connected to the safety injection line  215   a  by a line  2115  to use cooling water stored therein for safety injection. The cooling water storage section  2130  illustrated in the left side of the  FIG. 12  will be referred to such a structure. 
         [0217]    A safety injection facility  215 , which is another safety system of the nuclear power plant  210 , injects cooling water to the reactor coolant system  211  to maintain a water level of the reactor coolant system  211 . The safety injection facility  215  may include various tanks (not shown) for storing safety injection water, a safety injection line  215   a , a valve  215   b , and the like. The safety injection line  215   a  connects the tanks to the reactor coolant system  211 , and the valve  215   b  may be installed at the safety injection line  215   a . The cooling water storage section  2130  may be connected to the safety injection line  215   a  for safety injection. 
         [0218]    The cooling water storage section  2130  may include a first cooling water storage section  2130   a  and a second cooling water storage section  2130   b  to store pure cooling water to be used for residual heat removal and borated water to be used for safety injection, respectively, in a separate manner as illustrated in  FIG. 12 . 
         [0219]    The first cooling water storage section  2130   a  stores pure cooling water to be supplied to the steam generator  211   b  to remove sensible heat within the reactor coolant system  211  and residual heat in the core  211   a . The second cooling water storage section  2130   b  stores borated water to be directly injected into the reactor coolant system  211  to maintain the water level of the reactor coolant system  211 . 
         [0220]    The fluid circulation section  2140  is formed to circulate the cooling water of the cooling water storage section  2130  to the circulation inducing jet device  2120  through the reactor coolant system  211  or the steam generator  211   b . The fluid circulation section  2140  may include a fluid supply line  2141  and a steam discharge line  2142 . 
         [0221]    The fluid supply line  2141  is connected to the cooling water storage section  2130  to supply cooling water within the cooling water storage section  2130  to the reactor coolant system  211  or steam generator  211   b . The fluid supply line  2141  may be directly or indirectly connected to the reactor coolant system  211 . For example, the fluid supply line  2141  may be connected to the feedwater line  213   a  to supply cooling water to the steam generator  211   b  within the reactor coolant system  111  as illustrated in  FIG. 12 . An isolation valve  2141   a  and a check valve  2141   b  may be installed at the fluid supply line  2141 . 
         [0222]    The steam discharge line  2142  is connected to the reactor coolant system  211  or steam generator  211   b  and circulation inducing jet device  2120  to supply the first fluid discharged from the reactor coolant system  211  or steam generator  211   b  to the circulation inducing jet device  2120 . The steam discharge line  2142  is connected to the steam generator  211   b  to supply the first fluid discharged from the steam generator  211   b  to the circulation inducing jet device  2120  as illustrated in the drawing. An isolation valve  2142   a  may be installed at the steam discharge line  2142 . 
         [0223]    The return line  2160  is extended from the casing  2115  to the cooling water storage section to supply condensate collected in the lower portion  2115   b  of the casing  2115  to the cooling water storage section  2130 . A flow regulator  2160   a  for controlling the flow of the condensate may be installed at the return line  2160 . 
         [0224]    When the condensate is returned to the cooling water storage section  2130  through the return line  2160 , one circulation of cooling water started from the cooling water storage section  2130  is completed. The circulation of flow is induced in a passive method by natural forces, and thus the circulation of flow does not end by one circulation. The circulation of flow may continue to be sustained while a sufficient passive force capable of inducing the circulation of flow within the containment  212  is maintained by generating steam from the reactor coolant system  211  or steam generator  211   b.    
         [0225]    An additive injection section  2180  injects an additive into condensate for suppressing the revolatilization of condensate collected in the cooling water storage section  2130 . The additive is formed to maintain a pH of the condensate above a preset value. 
         [0226]    Radioactive iodine dissolved in cooling water exists in the form of negative ions, and when a pH of cooling water dissolved therein is low, the revolatilization amount of radioactive iodine may greatly increase. The reason is because an amount of radioactive iodine being converted to the form of volatile elemental iodine (2I2) greatly increases in cooling water below pH 7. In addition, the amount of being converted to elemental iodine is also related to a temperature of soluble cooling water, a concentration of iodine in the solution, and the like. The converted elemental iodine may be revolatilized into atmosphere according to a separation factor defined as a ratio of a concentration of iodine in cooling water to a concentration of iodine in atmosphere. According to the related regulatory requirements, when a pH of soluble cooling water is above 7.0, the amount of being converted to elemental iodine is sharply reduced to ignore revolatilization. 
         [0227]    Trisodium phosphate may be used for the additive, for example. Trisodium phosphate controls the pH of cooling water to prevent corrosion within the containment  212  and the revolatilization of radioactive nuclides during an accident. However, according to the present disclosure, the type of the additive may not be necessarily limited to this. Boric acid for suppressing the reactivity of the core  211   a  and other additives for suppressing the corrosion of the device or the like may be added to the additive to manage the water quality of the cooling water storage section  2130  in a passive manner. 
         [0228]    The cooling water storage section  2130  is configured to flow the condensate collected in the first cooling water storage section  2130   a  into the second cooling water storage section  2130   b  when a level of condensate collected in the first cooling water storage section  2130   a  exceeds a reference level. For example, when the level of the first cooling water storage section  2130   a  gradually increases and exceeds the reference level by the collection of the condensate, the condensate collected in the first cooling water storage section  2130   a  may overflow and flow into the second cooling water storage section  2130   b.    
         [0229]    The additive injection section  2180  may be installed at a flow path connected from the first cooling water storage section  2130   a  to the second cooling water storage section  2130   b  to inject the additive to condensate flowing into the second cooling water storage section  2130   b . Accordingly, the additive injection section  2180  may inject an additive into condensate flowing into the second cooling water storage section  2130   b.    
         [0230]    Hereinafter, the operation of the passive safety facility  2100  and the nuclear power plant  210  including the same during the occurrence of a virtual event will be described with reference to  FIG. 13 . 
         [0231]      FIG. 13  is a conceptual view illustrating when an event occurs on the passive safety facility  2100  and the nuclear power plant  210  including the same illustrated in  FIG. 12 . 
         [0232]    When an accident such as a loss of coolant accident occurs, isolation valves  213   b ,  214   b  installed at the feedwater line  213   a  and steam line  214   a , respectively, are closed, and valves  215   b  installed at the safety injection line  215   a  are open. Then, safety injection is implemented by the safety injection facility  215  to the reactor coolant system  211 . 
         [0233]    An isolation valve  2115   a  and a check valve  2115   b  are installed at a line  2115  connecting between the second cooling water storage section  2130   b  and the safety injection line  215   a , and the isolation valve  2115   a  and check valve  2115   b  are also open when an event occurs. Accordingly, when an internal pressure of the reactor coolant system  211  decreases, borated water stored in the second cooling water storage section  2130   b  is also injected into the reactor coolant system  211  by a gravity water head. The borated water stored in the second cooling water storage section  2130   b  performs the role of maintaining a water level within the reactor coolant system  211  along with the safety injection facility  215 . 
         [0234]    The isolation valve  2141   a  and check valve  2141   b  installed at the fluid supply line  2141  are also open to start the supply of cooling water due to a gravity water head from the first cooling water storage section  2130   a . The cooling water is supplied to a lower inlet of the steam generator  211   b  through the feedwater line  213   a . The cooling water removes sensible heat within the reactor coolant system  211  and residual heat in the core  211   a  in the steam generator  211   b , and is discharged to an upper outlet of the steam generator  211   b.    
         [0235]    The isolation valve  2142   a  installed at the steam discharge line  2142  is also open, and the first fluid discharged to an upper portion of the steam generator  211   b  is evaporated through the steam discharge line  2142 . The first fluid is supplied to the circulation inducing jet device  2120 , and the circulation inducing jet device  2120  jets the first fluid supplied through the steam discharge line  2142  and the second fluid entrained from an inside of the containment  212  by a pressure drop to an inside of the casing  2115 . 
         [0236]    The first fluid and second fluid jetted from the circulation inducing jet device  2120  exchange heat with the cooling water of the emergency cooling water storage section  2111  in the heat exchanger  2112 . The cooling water of the emergency cooling water storage section  2111  is supplied to the heat exchanger  2112  through the connected line  2113 , and exchanges heat with the first fluid and second fluid while passing through an internal flow path of the heat exchanger  2112 . The cooling water of the emergency cooling water storage section  2111  continuously circulates the emergency cooling water storage section  2111  and heat exchanger  2112  through the connected line  2113 . 
         [0237]    Heat is transferred to cooling water from the first fluid and second fluid. The first fluid and second fluid are cooled and condensed, and the cooling water is heated. The cooling water within the emergency cooling water storage section  2111  evaporates when the temperature increases. Accordingly, heat is discharged to an external environment. 
         [0238]    The condensate formed by cooling and condensing the first fluid and second fluid in the heat exchanger  2112  is collected into a lower portion  2115   b  of the casing  2115 . The collected condensate is guided through the return line  2160  and returned to the first cooling water storage section  2130   a . The circulation of flow is carried out in a continuous and consistent manner. 
         [0239]    When condensate is continuously collected in the first cooling water storage section  2130   a , the level of the first cooling water storage section  2130   a  gradually increases. Then, as the level of the first cooling water storage section  2130   a  increases, the condensate flows into the second cooling water storage section  2130   b  from the first cooling water storage section  2130   a . During the process, the additive injection section  2180  injects an additive to the condensate. Accordingly, the revolatilization of the condensate flowing into the second cooling water storage section  2130   b  may be suppressed. 
         [0240]    Noncondensible gas discharged along with the condensate is flowed into the filter facility  2170  and filtered out. The noncondensible gas is supplied to the filter or absorbent  2171  through a flow path formed by the gas line  2173 . The filter or absorbent  2171  separates radioactive materials from the noncondensible gas. The filtered noncondensible gas is discharged to an inside of the containment  212  through the gas discharge section  2172 . 
         [0241]    The present disclosure has an effect of reducing a concentration of radioactive materials within the containment  212  at an early stage by the filter facility  2170 . Assuming an accident at a nuclear power plant, an exclusion area boundary (EAB) is set to the nuclear power plant for the safety of the general public during an accident to limit the residence of the general public. The present disclosure may reduce the exclusion area boundary by the filter facility  2170 . 
         [0242]    Among the related arts, a filtered containment ventilation system (FCVS) has been developed to prevent the damage of the containment and reduce a concentration of radioactive materials discharged to an external environment during the occurrence of an accident in which a pressure within the containment greatly increases (AREVA in France, Westinghouse in United States, etc.). The concept in which a filter facility is installed at a boundary between an inside and an outside of the containment, and the boundary is open (using a rupture disc, a valve, etc.) when an accident occurs in which a pressure within the containment greatly increases, and atmosphere within the containment is discharged through the filter facility is applied to the filtered containment ventilation system (FCVS). 
         [0243]    When a design basis exceeding accident (here, design basis exceeding accident denotes an accident in which an internal pressure of the containment greatly increases above a design pressure) occurs at a nuclear power plant employing a filtered containment ventilation system in the related art, a rupture disc or valve installed between an inside of the containment and the filter facility is open, and a flow is formed by a pressure difference formed at an inside and an outside of the containment (a difference between a high pressure formed within the containment and an external atmospheric pressure). Then, atmosphere (air and steam) within the containment is passed through the filter facility and then discharged to an outside thereof by the flow. 
         [0244]    However, the filtered containment ventilation system in the related art does not operate during the occurrence of a design basis accident (here, design basis accident denotes an accident in which an internal pressure of the containment is within a design pressure range). Accordingly, the filtered containment ventilation system in the related art is unable to reduce the concentration of radioactive materials within the containment during the occurrence of a design basis accident, thereby causing a problem in which the amount of radioactive materials being leaked out of the containment cannot be greatly suppressed. 
         [0245]    On the contrary, the filter facility  2170  according to the present disclosure is configured to operate during the occurrence of all accidents including a design basis accident as well as a design basis exceeding accident. The filter facility  2170  is configured to discharge noncondensible gas having a very low radioactive material concentration into the containment  212 . Radioactive materials are collected into the filter facility  2170  while passing through the filter or absorbent  2171 . The present disclosure may very effectively reduce a radioactive material concentration within the containment  212 , thereby significantly reducing the amount of radioactive materials being leaked out of the containment  212 . Furthermore, the present disclosure may decrease the exclusion area boundary. 
         [0246]      FIG. 14  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2200  and a nuclear power plant  220  including the same associated with yet still another embodiment of the present disclosure. 
         [0247]    An emergency cooling water storage section  2211  is installed outside the containment  222 , and cooling water is stored within the emergency cooling water storage section  2211 . 
         [0248]    A heat exchanger  2212  is installed within the emergency cooling water storage section  2211 . An inlet header  2212   a  and an outlet header  2212   b  of the heat exchanger  2212  are respectively connected to a connected line  2213  passing through the containment  222 . The connected line  2213  is connected to a circulation inducing jet device  2220  to supply the first fluid and second fluid jetted from the circulation inducing jet device  2220  to the heat exchanger  2212 . Furthermore, another connected line  2213  is connected to a filter facility  2270  to supply condensate and noncondensible gas formed by the cooling of the first fluid and second fluid to the filter facility  2270 . 
         [0249]    The heat exchanger  2212  illustrated in  FIG. 14  is immersed in the cooling water of the emergency cooling water storage section  2211 . In this aspect, the cooling section  2210  of  FIG. 14  may be divided into an immersion type. However, the present embodiment illustrates an immersion type as an example, but may be also configured with an air-cooled type by exposing the heat exchanger  2212  to atmosphere and installing a duct (not shown) without installing the emergency cooling water storage section  2211 . 
         [0250]    The circulation inducing jet device  2220  is connected to a steam discharge line  2242  to supply the first fluid from a steam generator  221   b . The circulation inducing jet device  2220  is connected to the connected line  2213  to jet the first fluid received from the steam discharge line  2242  and the second fluid entrained by a pressure drop to the connected line  2213 . 
         [0251]    The heat exchanger  2212  allows the first fluid and second fluid entrained through the connected line  2213  to pass through an internal flow path to exchange heat with the cooling water of the emergency cooling water storage section  2211 . 
         [0252]    The filter facility  2270  is installed within the containment  222 . The containment  222  is connected to the heat exchanger  2212  by the connected line  2213  to receive condensate and noncondensible gas from the heat exchanger  2212 . A return line  2260  is extended from a lower portion of the filter facility  2270  to a first cooling water storage section  2230   a  to transfer condensate supplied to the filter facility  2270 . 
         [0253]      FIG. 15  is a conceptual view illustrating when an event occurs on a passive safely system  2200  and a nuclear power plant  220  including the same illustrated in  FIG. 14 . 
         [0254]    When an accident occurs on the nuclear power plant  220 , isolation valves  223   b ,  224   b  installed at the feedwater line  223   a  and steam line  224   a , respectively, are closed. Then, an isolation valve  2241   a  and a check valve  2241   b  installed at a fluid supply line  2241  are open, and an isolation valve  2215   a  and a check valve  2251   b  installed at a line  2215  for connecting between a second cooling water storage section  2230   b  and a safety injection line  225   a  are also open. 
         [0255]    The cooling water of the second cooling water storage section  2230   b  is safely injected into a reactor coolant system  221  along with the safety injection facility  225 . The cooling water of the first cooling water storage section  2230   a  is supplied to a steam generator  221   b  through the fluid supply line  2241  to remove sensible heat within the reactor coolant system  221  and residual heat in the core  221   a.    
         [0256]    During an accident, a steam discharge line  2242  and an isolation valve  2242   a  are open. The first fluid discharged from the steam generator  221   b  is evaporated through the steam discharge line  2242 , and supplied to the circulation inducing jet device  2220 . The second fluid is entrained into the circulation inducing jet device  2220  and jetted to the connected line  2213  along with the first fluid. The first fluid and second fluid are supplied to the heat exchanger  2212  through the connected line  2213 . The first fluid and second fluid are cooled and condensed by the cooling water of the emergency cooling water storage section  2211  while passing through an internal flow path of the heat exchanger  2212 . 
         [0257]    Condensate and noncondensible gas discharged from the heat exchanger  2212  are supplied to the filter facility  2270  through the connected line  2213 . The condensate in the filter facility  2270  is returned to the first cooling water storage section  2230   a  through the return line  2260 . The noncondensible gas in the filter facility  2270  is filtered out while passing through the filter or absorbent  2271 . The filtered noncondensible gas is discharged to an inside of the containment  222  through a gas discharge section  2272 . 
         [0258]      FIG. 16  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2300  and a nuclear power plant  230  including the same associated with still yet another embodiment of the present disclosure.  FIG. 17  is a conceptual view illustrating when an event occurs on the passive safely system  2300  and the nuclear power plant  230  including the same illustrated in FIG.  16 . 
         [0259]    The passive safely system  2300  is distinguished from that of the foregoing embodiment in that it includes a first cooling water storage section  2330   a  but does not include a second cooling water storage section. The passive safely system  2300  removes sensible heat within a reactor coolant system  231  and residual heat in a core  231   a  using a secondary system. The pure cooling water of the first cooling water storage section  2330   a  is supplied to a steam generator  231   b  for a passive residual heat removal function. 
         [0260]    A cooling section  2310  illustrated in  FIGS. 16 and 17  is the same as the cooling section  2110  illustrated in  FIG. 12 , and thus may be divided into a circulation type. The remaining configuration and operation will be substituted by the description of  FIGS. 12 and 13 . 
         [0261]      FIG. 18  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2400  and a nuclear power plant  240  including the same associated with yet still another embodiment of the present disclosure.  FIG. 19  is a conceptual view illustrating when an event occurs on the passive safely system  2400  and the nuclear power plant  240  including the same illustrated in  FIG. 18 . 
         [0262]    The passive safely system  2400  uses a primary system. 
         [0263]    A second cooling water storage section  2430   b  stores borated water to be injected into a reactor coolant system  241  to maintain a water level of the reactor coolant system  241 . The second cooling water storage section  2430   b  is connected to a safety injection line  245   a  by a fluid supply line  2441 . 
         [0264]    A steam discharge line  2442  is connected to the reactor coolant system  241  to supply the first fluid discharged from the reactor coolant system  241  to a circulation inducing jet device  2420 . 
         [0265]    An additive injection section  2480  may be installed at a line connected from a lower portion  2415   b  of a casing  2415  to the second cooling water storage section  2430   b  to inject an additive to condensate collected into the second cooling water storage section  2430   b . For example, the additive injection section  2480  may be installed at an outlet of a return line  2460 . The additive injection section  2480  may inject an additive to condensate returned to the second cooling water storage section through the return line  2460 . 
         [0266]    When a loss of coolant accident occurs in this embodiment, both the first fluid and second fluid are a primary fluid. However, in case of a steam line break, the first fluid is a primary fluid, and the second fluid is a secondary fluid. The primary fluid circulates the passive safely system  2400  from the time of being started from the second cooling water storage section  2430   b  to the time of being returned to the second cooling water storage section  2430   b . The passive safely system  2400  is different from the foregoing embodiment in that it uses a primary system without using a steam generator  241   b.    
         [0267]      FIG. 20  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2500  and a nuclear power plant  250  including the same associated with still yet another embodiment of the present disclosure.  FIG. 21  is a conceptual view illustrating when an event occurs on the passive safely system  2500  and the nuclear power plant  250  including the same illustrated in  FIG. 20 . 
         [0268]    A cooling section  2510  may include a first heat exchanger  2512 ′ and a second heat exchanger  2512 ″. 
         [0269]    The first heat exchanger  2512 ′ is installed within a containment  252  to cool the first fluid and second fluid jetted from a circulation inducing jet device  2520 . The present embodiment illustrates an immersion type as an example. However, according to the characteristics of the nuclear power plant  250 , the cooling section  2510  may be also configured with an air-cooled type by exposing the second heat exchanger  2512 ″ to atmosphere and installing a duct (not shown) without installing the emergency cooling water storage section  2511 . 
         [0270]    The second heat exchanger  2512 ″ is installed within the emergency cooling water storage section  2511 . Furthermore, an isolation valve  2514   a  or check valve  2514   b  is installed at a connected line  2513 . The second heat exchanger  2512 ″ transfers heat that has transferred to a fluid circulating a closed flow path to cooling water within the emergency cooling water storage section  2511 . 
         [0271]    When the first fluid and second fluid are jetted to a casing  2515  from a circulation inducing jet device  2520 , the first fluid and second fluid are cooled and condensed by a fluid circulating a closed flow path of the first heat exchanger  2512 ′. Condensate formed by the condensation of the first fluid and second fluid is collected into a lower portion  2515   b  of the casing  2515 , and returned to a first cooling water storage section  2530   a  through a return line  2560 . 
         [0272]    The fluid within the closed flow path that has received heat from the first fluid and second fluid flows to the second heat exchanger  2512 ″ through the connected line  2513 . Heat in the second heat exchanger  2512 ″ is transferred to the cooling water of the emergency cooling water storage section  2511  from the fluid within the closed flow path. The emergency coolant storage section evaporates cooling water to discharge heat to an outside thereof. The fluid continuously receives the heat of the first fluid and second fluid while circulating the closed flow path. 
         [0273]    The cooling section  2510  may further include a makeup tank  2516 . 
         [0274]    The makeup tank  2516  is formed to store makeup water. The makeup tank  2516  is connected to the connected line  2513  to supply makeup water to the closed flow path or accommodate the excess water of the closed flow path. An isolation valve  2516   b  is installed at a line  2516   a  connecting between the makeup tank and the connected line  2513 . The isolation valve  2516   b  may be configured to be open at a time point at which the supply of makeup water is required or configured to be open in advance. A fluid within the closed flow path may receive makeup water to maintain a sufficient water level. 
         [0275]      FIG. 22  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2600  and a nuclear power plant  260  including the same associated with yet still another embodiment of the present disclosure. 
         [0276]    An emergency cooling water storage section  2611  is installed outside a containment  262 , and a heat exchanger  2612  is installed within the containment  262 . A connected line  2613  may include a first connected line  2613   a  through a fourth connected line  2613   d.    
         [0277]    The first connected line  2613   a  is connected to the emergency cooling water storage section  2611  and the heat exchanger  2612  to form a flow path for supplying the cooling water of the emergency cooling water storage section  2611  to the heat exchanger  2612 . In  FIG. 22 , the first connected line  2613   a  indicates a portion extended from a lower portion of the emergency cooling water storage section  2611  to a first header  2612   a  of the heat exchanger  2612 . The first connected line  2613   a  allows the cooling water of the emergency cooling water storage section  2211  to flow into the heat exchanger  2612  to implement water-cooled type cooling. 
         [0278]    A second connected line  2613   b  is extended from the heat exchanger  2612  to an outside of the containment  262  to discharge the cooling water of the emergency cooling water storage section  2611  that has passed through the heat exchanger  2612  to an outside thereof. In  FIG. 22 , the second connected line  2613   b  indicates a portion extended from a second header  2612   b  of the heat exchanger  2612  to an outside of the containment  222  and continuously extended in a downward bending manner. 
         [0279]    A third connected line  2613   c  is branched from the second connected line  2613   b  to form a flow path for supplying atmosphere outside the containment  262  to the heat exchanger  2612 . In  FIG. 22 , the third connected line  2613   c  indicates a portion branched from the second connected line  2613   b  and continuously extended to an outside of the containment  262 . The third connected line  2613   c  allows the atmosphere of the containment  262  to flow into the heat exchanger  2612  so as to implement air-cooled type cooling when the cooling water of the emergency cooling water storage section  2611  is exhausted. 
         [0280]    A fourth connected line  2613   d  is branched from the first connected line  2613   a  to an outside of the containment  262  to discharge atmosphere heated while passing through the heat exchanger  2612  to an outside thereof. In  FIG. 22 , the fourth connected line  2613   d  indicates a portion branched from the first connected line  2613   a  and connected to a duct  2617 . 
         [0281]    The duct  2617  is an air circulation system for exhausting atmosphere discharged from the heat exchanger  2612 . 
         [0282]    At least one of isolation valves  2614   a ′.  614   a ″,  614   b ′,  614   b ″,  614   c ,  614   d  is installed at each connected line  2613   a ,  613   b ,  613   c ,  613   d . Cooling medium flowing into the heat exchanger  2612  differs according to which one of the isolation valves  2614   a ′.  614   a ″,  614   b ′,  614   b ″,  614   c ,  614   d  is open. The cooling method of a cooling section  2610  may be switched to either one of water-cooled type cooling and air-cooled type cooling according to the switching of the isolation valves  2614   a ′.  614   a ″,  614   b ′,  614   b ″,  614   c ,  614   d . The present embodiment illustrates a case of mixing the water-cooled type with the air-cooled type, but may be also configured with an air-cooled exclusive type by removing a water-cooled type related facility according to the characteristics of the nuclear power plant. 
         [0283]      FIGS. 23 and 24  are conceptual views illustrating when an event occurs on a passive safely system  2600  and a nuclear power plant  260  including the same illustrated in  FIG. 22 . The passive safely system  2600  undergoes a sequential operation process in  FIGS. 23 and 24 . 
         [0284]    First, referring to  FIG. 23 , the pure cooling water of a first cooling water storage section  2630   a  is supplied to a steam generator  261   b  as an accident occurs on the nuclear power plant. The first fluid discharged from the steam generator  261   b  is supplied to a circulation inducing jet device  2620  through a steam discharge line  2642 . The circulation inducing jet device  2620  jets the first fluid and second fluid to an inside of the casing  2615 . 
         [0285]    When an accident occurs, isolation valves  2614   a ′,  614   b ″ installed at a first connected line  2613   a  and a second connected line  2613   b  are open by an associated signal. Other isolation valves  2614 ″,  614 ′ installed at the first connected line  2613   a  and second connected line  2613   b  may be set to be open at the time point at which the maintenance is required, and to be closed when the isolation of the containment  262  is required due to the damage of the system or the like during an accident. Cooling water that has been stored in the emergency cooling water storage section  2611  is injected into the heat exchanger  2612  by a gravity water head. The cooling water is injected into the heat exchanger  2612  through the first connected line  2613   a.    
         [0286]    The cooling water injected into the heat exchanger  2612  receives heat from the first fluid and second fluid in the heat exchanger  2612 . The cooling water is discharged to an outside of the containment  262  through the second connected line  2613   b . The first fluid and second fluid are cooled and condensed, and collected to a lower portion of the casing  2615 . Noncondensible gas is filtered out by the filter facility  2670 . Condensate is returned again to the first cooling water storage section through a return line  2660 . 
         [0287]    In the aspect that cooling water that has been stored in the emergency cooling water storage section  2611  is injected into the heat exchanger  2612 , the cooling section  2610  illustrated in  FIGS. 22 through 24  may be divided into an injection type. The injection type may be divided again into a gravity injection type and a gas injection type. The gravity injection type injects cooling water based on a gravity head. The gas injection type pressurizes cooling water with gas filled in the sealed emergency cooling water storage section  2211  to inject cooling water. In the aspect that cooling water injection in  FIGS. 22 through 24  is carried out by gravity, the cooling section  2610  is divided into a gravity injection type. 
         [0288]    The gravity injection type cooling may continue until the cooling water of the emergency cooling water storage section  2611  is exhausted. The operation of the passive safely system  2600  after the cooling water of the emergency cooling water storage section  2611  is exhausted will be described with reference to  FIG. 24 . 
         [0289]    Referring to  FIG. 24 , an isolation valve  2614   b ″ installed at the second connected line  2613   b  is closed, and isolation valves  2614   c ,  614   d  installed at the third connected line  2613   c  and fourth connected line  2613   d  are open. Accordingly, cooling carried out with a water-cooled type is switched to an air-cooled type. Atmosphere outside the containment  262  flows into the heat exchanger  2612  through the third connected line  2613   c . The atmosphere that has received heat from the first fluid and second fluid in the heat exchanger  2612  flows again into the duct  2617  through the fourth connected line  2613   d . The atmosphere is discharged to an outside thereof through the duct  2617 . 
         [0290]    As illustrated in  FIGS. 23 and 24 , when cooling is carried out with a mixed type of both the water-cooled type and air-cooled type, the passive safely system  2600  may be more securely prepared for an accident. Cooling is carried out with the water-cooled type having a high cooling efficiency at an early stage of the accident with a large thermal load, and consistent cooling may be carried out with the air-cooled type in which the makeup of cooling water is not required at a later stage of the accident with a low thermal load. 
         [0291]      FIG. 25  is a conceptual view illustrating when a normal operation is carried out on a passive safely system  2700  and a nuclear power plant  270  including the same associated with still yet another embodiment of the present disclosure,  FIG. 26  is an enlarged conceptual view illustrating part of the passive safely system  2700  illustrated in  FIG. 25 . 
         [0292]    A return line  2760  is connected to a lower portion of the casing  2715 , and extended from the lower portion  2715   b  of the casing  2715  to a first cooling water storage section  2730   a . The return line  2760  forms a flow path of condensate collected in the casing  2715 . Condensate is returned to the first cooling water storage section  2730   a  from the casing  2715  through the return line  2760 . 
         [0293]    A return line  2774  is connected to a lower portion of a filter facility  2770  in addition to the return line  2760  connected to the lower portion  2715   b  of the casing  2715 . In order to distinguish two return lines  2760 ,  2774 , the return line  2760  connected to the casing  2715  is referred to as a first return line  2760 , and the return line  2774  connected to a lower portion of the filter facility  2770  is referred to as a second return line  2774 . The second return line  2774  is connected to the first return line  2760 . 
         [0294]    Condensate generated during the cooling process of the cooling section  2710  may be collected to a lower portion of the casing  2715 , but part thereof may be flowed to a lower portion of the filter facility  2770 . Condensate collected to the lower portion  2715   b  of the casing  2715  is returned to the first cooling water storage section  2730   a  through the first return line  2760 . Condensate collected to the lower portion of the filter facility  2770  is returned to the first cooling water storage section  2730   a  through the second connected line  2774 . 
         [0295]    Referring to  FIG. 26 , at least part of the first return line  2760 ′ forms a height difference from another part thereof. When the first return line  2760 ′ with the foregoing structure is used, it may be possible to block the discharge of air, thereby preventing noncondensible gas containing radioactive materials from being discharged through the first return line  2760 . 
         [0296]      FIGS. 27 through 29  are conceptual views illustrating a circulation inducing jet device  1120  and a modified example thereof  3820 ,  3920 . 
         [0297]      FIG. 27  illustrates the circulation inducing jet device  1120  illustrated in  FIG. 1 , and uses the principle of a jet pump. The description thereof will be substituted by the earlier description. 
         [0298]      FIGS. 28 and 29  as a modified example of a circulation inducing jet device  3820 ,  3920  different from  FIG. 27  uses the principle of a turbine pump other than a jet pump. The circulation inducing jet device  3820 ,  3920  may include a first fluid jetting section  3821 ,  3921 , a second fluid entraining section  3822   b ,  3922   b , a circulating fluid jetting section  3822 ,  3922 , a turbine blade  3823 ,  3923 , and a pump impeller  3824 ,  3924 . 
         [0299]    The turbine blade  3823 ,  3923  and pump impeller  3824 ,  3924  are installed at an outlet of the first fluid jetting section  3821 ,  3921 , and when the rotational force thereof is used, it may be possible to entrain the second fluid within the containment to promote circulation flow within the containment. 
         [0300]    Referring to  FIG. 28 , a turbine may include a relatively small-sized turbine blade  3823  disposed at an outlet of the first fluid jetting section  3821  and a relatively large-sized pump impeller  3824  disposed at a position separated by a predetermined distance from the outlet of the first fluid jetting section  3821 . 
         [0301]    Referring to  FIG. 29 , the position of the pump impeller  3924  is disposed closer to the turbine blade  3923  than that of the pump impeller  3824  of  FIG. 28 . 
         [0302]    In the circulation inducing jet device  3820 ,  3920  illustrated in  FIGS. 28 and 29 , the turbine blade  3823 ,  3923  induces an efficient jetting of the first fluid, and the pump impeller  3824 ,  3924  induces an efficient jetting of the second fluid. 
         [0303]    The present disclosure may promote circulation flow using a circulation inducing jet device without merely depending on natural circulation to increase an efficiency of cooling an inside of the containment. The first fluid discharged from the reactor coolant system may be directly supplied to the heat exchanger without discharging the first fluid to an inside of the containment as well as the second fluid within the containment may be induced to the heat exchanger at the same time, thereby solving the problems of size increase, cost increase and safety degradation in the heat exchanger for cooling the containment in a nuclear power plant. 
         [0304]    In addition, the present disclosure may filter out non-condensate using a filter facility without discharging the non-condensate as it is to an inside of the containment. Accordingly, it may be possible to reduce a concentration of radioactive materials within the containment at an early stage. As the concentration of radioactive materials is reduced, the present disclosure may decrease the exclusion area boundary. 
         [0305]    The configurations and methods according to the above-described embodiments will not be applicable in a limited way to the foregoing passive safety facility and a nuclear power plant including the same, and all or part of each embodiment may be selectively combined and configured to make various modifications thereto. 
         [0306]    The present disclosure may be used for safety enhancement in the nuclear power plant industry.