JP2015034734A - Steam processing system of nuclear power plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a steam processing system of a nuclear power plant which is capable of reducing contamination in a nuclear reactor containment vessel caused by a radioactive substance in processing the steam generated by decay heat in a reactor pressure vessel.SOLUTION: A steam separator 2 in which a plurality of tubular steam-separating films 3 is arranged in a casing, is arranged in a dry well 26 of a nuclear reactor containment vessel 25. One side end parts of the steam separating films 3 are communicated with a reactor pressure vessel 24 by a steam supply pipe 11 and a main steam piping 30, and the another side end parts of the steam separating films 3 are communicated with the vessel 24 by a steam discharge pipe 9. A steam discharge pipe 13 in the steam separator 2 which is communicated with an outside region of the steam separating film 3 is connected to a reactor isolation time cooling system turbine 6 arranged outside the nuclear reactor containment vessel 25. A reactor isolation time cooling system pump 7 which is connected with the reactor isolation time cooling system turbine 6 to be connected with a cooling water supply pipe 18, is connected to the reactor pressure vessel 24 by a cooling water supply pipe 22. A steam discharge pipe 17 connected to the reactor isolation time cooling system turbine 6 reaches a pressure suppression pool 28 in a pressure suppression chamber 27.

Description

  The present invention relates to a steam treatment system for a nuclear power plant, and more particularly to a steam treatment system for a nuclear power plant suitable for application to a boiling water nuclear power plant.

  In the boiling water nuclear power plant, in order to control the temperature and pressure in the reactor pressure vessel when the operation is stopped, a reactor core cooling device of a reactor isolation cooling system is provided as a regular and emergency system. An example of a reactor isolation cooling system using steam generated by decay heat in a nuclear reactor is described in Japanese Patent Application Laid-Open No. 2012-233724. In this reactor isolation cooling system, a turbine and a pump connected to the turbine are installed outside the reactor containment vessel, and steam generated by decay heat in the reactor is guided to the turbine to rotate the turbine. As a result, the pump is rotated, and the cooling water of the suppression pool in the condensate storage tank and the pressure suppression chamber is poured into the core in the nuclear reactor to cool the fuel assembly in the core. The water vapor discharged from the turbine is condensed by the cooling water in the suppression pool.

  As a system for controlling the temperature and pressure in the reactor pressure vessel other than the reactor isolation cooling system, there is an emergency condenser system. An example of an emergency condenser system is described in Japanese Patent No. 2965312. The emergency condenser system, that is, the condenser, is installed in the pool water outside the reactor containment vessel. In this emergency condenser system, when the reactor is isolated, water vapor generated by decay heat in the reactor is condensed in the condenser in the pool, and the generated condensed water is guided to the reactor pressure vessel by gravity. It is burned. By supplying the condensed water into the reactor pressure vessel, the fuel assembly in the core is cooled.

  If core cooling systems such as the reactor isolation cooling system and the emergency condenser system do not function sufficiently, steam is generated by decay heat, and the pressure inside the reactor pressure vessel becomes high. At this time, the main steam relief safety valve provided in the main steam pipe connected to the reactor pressure vessel is operated, and the water vapor in the reactor pressure vessel is led to the pressure suppression pool in the pressure suppression chamber and condensed. An example of this main steam relief safety valve is described in Japanese Patent No. 3411654. The boiling water nuclear power plant also includes a safety valve that directly opens steam to the dry well by a spring drive, in addition to the main steam relief safety valve having such a function.

JP 2012-233724 A No. 2965312 Japanese Patent No. 3411654 JP 2000-2782 A

  In a boiling water nuclear power plant, corrosion products activated in a reactor pressure vessel are generated during normal operation. This activated corrosion product adheres to the inner surface of equipment and piping of the core cooling device used during normal operation, such as a reactor isolation cooling system. In addition, in a core cooling system such as a reactor isolation cooling system, if the piping arranged outside the reactor containment vessel breaks, the activated corrosion products are removed from the reactor containment vessel. There is a possibility of leakage.

  In order to prevent such contamination outside the core cooling device and the reactor containment vessel, and to simplify the periodic inspection of the nuclear power plant, the inventors have released the activated corrosion products in the reactor pressure vessel. We thought that it would be effective to discharge only water vapor to the outside of the reactor pressure vessel without releasing it outside, and considered the use of a water vapor separation membrane. By separating the water vapor in the reactor pressure vessel through the water vapor separation membrane, the activated corrosion product remains in the reactor pressure vessel, and the water vapor that has passed through the water vapor permeable membrane is removed from the reactor pressure vessel. Can be exhausted. As the water vapor separation membrane, an inorganic membrane such as ceramic and a polymer membrane such as polyimide have been developed for general industries.

  A reactor containment vessel atmosphere control device is described in Japanese Patent Application Laid-Open No. 2000-2782. A water vapor separation membrane filtration device provided with a water vapor separation membrane is disposed outside the reactor containment vessel and connected to the reactor containment vessel by piping. Japanese Patent Application Laid-Open No. 2000-2782 aims to suppress contamination in the reactor containment vessel when primary water leaks in the reactor containment vessel. For this reason, the reactor containment atmosphere control device described in Japanese Patent Application Laid-Open No. 2000-2782 uses an oxygen gas separation membrane filtration device provided with an oxygen gas separation membrane inside, in addition to the water vapor separation membrane filtration device. It is installed outside the reactor containment vessel. An oxygen gas separation membrane filtration device is also connected to the reactor containment vessel. The water vapor generated in the reactor containment vessel due to the leakage of the primary system water passes through the water vapor separation membrane and is discharged to the dehumidifier.

In the reactor containment atmosphere control device described in Japanese Patent Application Laid-Open No. 2000-2782,
Since the water vapor generated by the decay heat in the reactor pressure vessel cannot be processed, contamination in the core cooling device and the reactor containment vessel cannot be prevented.

  An object of the present invention is to provide a steam treatment system for a nuclear power plant that can reduce contamination in a nuclear reactor containment vessel due to radioactive substances when treating water vapor generated by decay heat in a reactor pressure vessel.

  A feature of the present invention that achieves the above-described object is that the water vapor generated in the reactor pressure vessel is disposed in the dry well in the reactor containment vessel surrounding the reactor pressure vessel and communicated with the reactor pressure vessel. A water vapor separator that contains a plurality of annular water vapor separation membranes that pass through the water vapor, and a water vapor discharge pipe that is connected to the water vapor separator and exhausts the water vapor that has passed through the water vapor separation membrane to the outside of the water vapor separator. is there.

  The operation of the nuclear power plant is stopped, and the water vapor generated by the decay heat of the nuclear fuel material in the reactor pressure vessel and containing the radioactive material is supplied into each of the tubular water vapor separation membranes of the water vapor separation device. Since the radioactive material is separated from the water vapor by permeating the membrane, the contamination of the steam discharge pipe from which the water vapor that has permeated the water vapor separation membrane is discharged is prevented, and the containment vessel by the radioactive material is prevented. Contamination inside is reduced.

  The above-described purpose is to arrange the water vapor generated in the reactor pressure vessel inside the reactor pressure vessel surrounded by the reactor containment vessel, and located above the water surface of the cooling water and opened to the reactor pressure vessel. A water vapor separator that contains a plurality of permeating annular water vapor separation membranes, and a water vapor discharge pipe that is connected to the water vapor separation device and exhausts the water vapor that has permeated through the water vapor separation membrane to the outside of the reactor pressure vessel outside the water vapor separation device Can also be achieved.

  The operation of the nuclear power plant is stopped, and the water vapor generated by the decay heat of the nuclear fuel material in the reactor pressure vessel and containing the radioactive material is supplied into each of the tubular water vapor separation membranes of the water vapor separation device. Since the radioactive material is separated from the water vapor by permeating the membrane, the contamination of the steam discharge pipe from which the water vapor that has permeated the water vapor separation membrane is discharged is prevented, and the containment vessel by the radioactive material is prevented. Contamination inside is reduced.

  According to the present invention, when the operation of the nuclear power plant is stopped and water vapor is generated in the reactor pressure vessel due to the decay heat of the nuclear fuel material, the atoms caused by the radioactive material contained in the water vapor generated in the reactor pressure vessel Contamination in the reactor containment vessel can be reduced.

It is a block diagram of the steam treatment system of the nuclear power plant of Example 1 which is one suitable Example of this invention. It is a block diagram of the steam processing system of the nuclear power plant of Example 2 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 3 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 4 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 5 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 6 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 7 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 8 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 9 which is another suitable Example of this invention. It is a block diagram of the steam treatment system of the nuclear power plant of Example 10 which is another suitable Example of this invention.

  Examples of the present invention will be described below.

  A steam treatment system for a nuclear power plant according to embodiment 1, which is a preferred embodiment of the present invention, will be described with reference to FIG.

  A boiling water nuclear power plant to which the steam treatment system 1 of the nuclear power plant of the present embodiment is applied will be described. In the boiling water nuclear power plant, a reactor pressure vessel 24 is installed in a reactor containment vessel 25, and a main steam pipe 30 is connected to the nuclear pressure vessel 24. The reactor containment vessel 25 forms therein a dry well 26 and a pressure suppression chamber 27 which are separated from each other. A pressure suppression pool 28 filled with cooling water is provided in the pressure suppression chamber 27. The reactor pressure vessel 24 is disposed in the dry well 26. The main steam pipe 30 penetrates the reactor containment vessel 25 and is provided with isolation valves 31 and 32 inside and outside the reactor containment vessel 25. Although not shown, the main steam pipe 30 is connected to a turbine connected to a generator. The boiling water nuclear plant has a condensate storage tank 29 installed outside the nuclear containment vessel 25.

  The steam treatment system 1 of the present embodiment includes a steam separator 2, an isolation cooling system turbine 6, an isolation cooling system pump 7, and a circulation pump 8. The water vapor separator 2 is disposed in the dry well 26 and has a plurality of tubular water vapor separation membranes 3. The water vapor separation membrane 3 is a tubular hollow membrane. That is, the water vapor separation membrane 3 is a thin tube. The water vapor separator 2 has a casing, and an inlet header portion 5 and an outlet header portion 4 are provided in the casing. One end of each tubular water vapor permeable membrane 3 disposed in the casing is attached to one partition plate that is installed in the casing and delimits the inlet header portion 5, and communicates with the inlet header portion 5. The other end of each tubular water vapor permeable membrane 3 disposed in the casing is attached to another partition plate that is installed in the casing and defines the outlet header portion 4, and communicates with the outlet header portion 4. The casing of the water vapor separator 2 is provided with a heater (not shown) for heating the water vapor separation membrane 3. A steam supply pipe 11 connected to the main steam pipe 30 upstream of the isolation valve 31 is connected to the casing of the steam separator 2 and communicated with the inlet header 5. An on-off valve 12 is installed in the water vapor supply pipe 11. A steam discharge pipe 9 connected to the casing of the steam separator 2 and connected to the outlet header portion 4 is connected to the reactor pressure vessel 24 and is located above the coolant level in the reactor pressure vessel 24. To be contacted. A circulation pump 8 is provided in the water vapor discharge pipe 9. An on-off valve 10 is provided in the water vapor discharge pipe 9 upstream of the circulation pump 8.

  The water vapor discharge pipe 13 is connected to the casing of the water vapor separation device 2 and communicates with a region formed outside the water vapor separation membrane 3 between the inlet header portion 5 and the outlet header portion 4 in the casing. The steam discharge pipe 13 passes through the reactor containment vessel 25 and is connected to the steam inlet of the isolation-time cooling system turbine 6 installed outside the reactor containment vessel 25. Isolation valves 15 and 16 arranged inside and outside the reactor containment vessel 25 are installed in the steam discharge pipe 13. A flow control valve 14 is provided in the water vapor discharge pipe 13 downstream of the isolation valve 16. The water vapor discharge pipe 17 connected to the water vapor outlet of the isolation-time cooling system turbine 6 reaches the pressure suppression chamber 27, and the tip of the water vapor discharge pipe 17 is immersed in the cooling water in the pressure suppression pool 28.

  The isolation cooling system pump 7 is connected to the isolation cooling system turbine 6. The cooling water supply pipe 22 is connected to the cooling water discharge port of the isolation-time cooling system pump 7, passes through the reactor containment vessel 25, passes through the dry well 26, and is connected to the reactor pressure vessel 24. An on-off valve 23 is provided in the cooling water supply pipe 22 in the dry well 26. A cooling water supply pipe 18 connected to the cooling water supply port of the isolation cooling system pump 7 is connected to the condensate storage tank 29. An on-off valve 19 is provided in the cooling water supply pipe 18. The condensate storage tank 29 is filled with cooling water 29A. A cooling water supply pipe 20 connected to the cooling water supply pipe 18 upstream of the on-off valve 19 passes through the reactor containment vessel 25 and communicates with the pressure suppression pool 28. An on-off valve 21 is provided in the cooling water supply pipe 20.

  During normal operation of the boiling water nuclear power plant, the isolation valves 31 and 32 are open, and the steam generated in the reactor pressure vessel 24 is supplied to the turbine through the main steam pipe 30. As a result, the turbine rotates and the generator connected to the turbine also rotates to generate power. At this time, the on-off valves 10 and 12 and the isolation valves 15 and 16 are closed. Furthermore, the on-off valves 19 and 21 are also closed.

  When the operation of the boiling water nuclear power plant in one operation cycle is finished and the boiling water nuclear power plant is stopped, the isolation valves 31 and 32 are fully closed, and the reactor pressure vessel 24 passes through the main steam pipe 30. The supply of steam to the turbine is stopped. Even if the operation of the boiling water nuclear plant is stopped, the decay pressure of the nuclear fuel material contained in the fuel rod of each fuel assembly loaded in the reactor core in the reactor pressure vessel 24 causes The cooling water is heated to generate water vapor. The pressure in the reactor pressure vessel 24 rises due to the generation of water vapor. In order to suppress this pressure increase, the on-off valves 10, 12, 19 and the isolation valves 15, 16 are opened, and the circulation pump 8 is driven. At this time, the on-off valve 21 is closed. Steam generated in the reactor pressure vessel 24 by decay heat is discharged from the reactor pressure vessel 24 to the main steam pipe 30 and supplied to the steam separator 2 through the steam supply pipe 11. In the water vapor separation device 2, the water vapor flowing into the inlet header portion 5 is supplied into each tubular water vapor separation membrane 3 and permeates the water vapor separation membrane 3. The water vapor that has passed through the water vapor separation membrane 3 reaches a region formed outside the water vapor separation membrane 3 in the casing of the water vapor separation device 2, and is supplied to the cooling system turbine 6 through the water vapor discharge pipe 13. A part of the water vapor supplied into the water vapor separation membrane 3 is discharged to the outlet header portion 4, pressurized by the circulation pump 8, and returned to the reactor pressure vessel 24 through the water vapor discharge pipe 9.

  The water vapor discharged from the reactor pressure vessel 24 to the water vapor supply pipe 11 contains radioactive substances such as activated corrosion products. The water vapor separation membrane 3 of the water vapor separation device 2 does not transmit the radioactive substance contained in the water vapor but transmits only the water vapor. The radioactive material that has flowed into the water vapor separation membrane 3 is returned to the reactor pressure vessel 24 together with the water vapor discharged to the outlet header portion 4.

  When water vapor is supplied to the isolation cooling system turbine 6, the isolation cooling system turbine 6 rotates and the isolation cooling system pump 7 also rotates. Due to the rotation of the isolation cooling system pump 7, the cooling water 29 </ b> A in the condensate storage tank 29 reaches the isolation cooling system pump 7 and is pressurized and supplied to the reactor pressure vessel 24 through the cooling water supply pipe 22. The water vapor discharged from the isolation cooling system turbine 6 is discharged into the cooling water in the pressure suppression pool 28 through the water vapor discharge pipe 17 and condensed. Since the water vapor in the reactor pressure vessel 24 passes through the water vapor separation membrane 3 of the water vapor separator 2 and rotates the isolation cooling system turbine 6 and is condensed in the pressure suppression pool 28, Cooling water level is lowered. However, since the cooling water 29A boosted by the isolation cooling system pump 7 is supplied into the reactor pressure vessel 24, the cooling water in the reactor pressure vessel 24 does not decrease. The fuel assembly in the core is cooled by the cooling water 29 </ b> A having a low temperature supplied into the reactor pressure vessel 24.

  When the cooling water 29A in the condensate storage tank 29 is supplied to the reactor pressure vessel 24 and the water level of the cooling water 29A in the condensate storage tank 29 is lowered to the set water level, the on-off valve 21 is opened and opened. The valve 19 is closed. For this reason, the cooling water in the pressure suppression pool 28 is boosted by the isolation cooling system pump 7 through the cooling water supply pipes 20 and 18. The increased cooling water is supplied to the reactor pressure vessel 24 through the cooling water supply pipe 22.

  The steam treatment method using the steam treatment system 1 described above will be described more specifically.

The tubular water vapor separation membrane 3 installed in the water vapor separation device 2 is a kind of ceramic membrane, and is a hollow fiber membrane having a thickness of 1.0 μm, a length of 1.5 m, and an outer diameter of 1 cm. A plurality of such water vapor separation membranes 3 are bundled and installed in a casing of the water vapor separation device 2 having a size of 1.5 m in length, 1.5 m in width, and 1.5 m (3.38 m ³ ) in height. The At this time, the total area of the water vapor separation membrane 3 is 2119 m ² . The water vapor permeability coefficient of the hollow membrane is about 2 × 10 ⁻⁷ mol / s · m ² · Pa at 150 ° C. The water vapor permeability coefficient of the hollow membrane generally becomes higher as the temperature at which water vapor is processed is higher.

  When the pressure in the reactor pressure vessel 24 increases due to the shutdown of the boiling water nuclear power plant, the heater provided in the steam separator 2 is energized to heat the steam separation membrane 3 to 150 ° C. The water vapor temperature in the reactor pressure vessel 24 is 280 ° C., and the heat resistance temperature of the hollow core membrane is 800 ° C. When the temperature of the water vapor separation membrane 3 is maintained at 150 ° C. or higher due to the supply of water vapor in the reactor pressure vessel 24, the energization of the heater of the water vapor separation device 2 is stopped. In order to supply steam from the reactor pressure vessel 24 to the steam separator 2, the on-off valves 10 and 12 and the isolation valves 15 and 16 are opened as described above. Further, the on-off valve 19 is opened. The water vapor in the reactor pressure vessel 24 is supplied to the water vapor separator 2 and contacts the water vapor separation membrane 3. The water vapor separation membrane 3 transmits water vapor from a region having a high water vapor partial pressure to a region having a low water vapor partial pressure. For this reason, the water vapor passes through the tubular water vapor separation membrane 3 from the inside of the water vapor separation membrane 3 toward the outside of the water vapor separation membrane 3. In principle, the water vapor separation membrane until the water vapor reaches a water vapor partial pressure in a region where the water vapor partial pressure is high (region outside the water vapor separation membrane 3) (region inside the water vapor separation membrane 3). 3 continues to pass through. In order to prevent radioactive substances contained in the water vapor from accumulating inside the water vapor separation membrane 3, the water vapor always flows from the water vapor supply pipe 11 toward the water vapor discharge pipe 9 by driving the circulation pump 8. It flows inside the separation membrane 3.

The pressure in the reactor pressure vessel 24 is 7.0 MPa during normal operation of the boiling water nuclear power plant, and the pressure resistance of the reactor pressure vessel 24 is 9.0 MPa. The pressure resistance of the hollow core membrane is 18 to 31 MPa. The amount of water vapor generated by the decay heat in the reactor pressure vessel 24 is about 70 t / h. The total area of the hollow core membrane disposed in the water vapor separator 2 is 2119 m ² , the water vapor transmission coefficient of the hollow core membrane is 2 × 10 ⁻⁷ mol / s · m ² · Pa, and the pressure in the hollow core membrane is 7. When the pressure of 0 MPa and the pressure in the outer region of the hollow core membrane in the water vapor separator 2 is 4.5 MPa, the water vapor treatment capacity of all the hollow core membranes of the water vapor separator 2 is 70 t / h, which passes through the hollow core membrane. The flow rate of water vapor is 0.012 m / s.

  The water vapor that has passed through the water vapor separation membrane 3 drives the isolation cooling system turbine 6 and rotates the isolation cooling system pump 7. The driving pressure of the isolation cooling system turbine 6 is 1.1 to 8.2 MPa, and the flow rate adjusting valve 14 is adjusted so that the pressure of the water vapor supplied to the isolation cooling system turbine 6 is maintained at 1.1 MPa or more. Control the opening. The water vapor discharged from the isolation cooling system turbine 6 is condensed by the cooling water in the pressure suppression pool 28.

  In the present embodiment, by adjusting the opening degree of the flow rate adjusting valve 14, the water vapor partial pressure inside the tubular water vapor separation membrane 3 and the water vapor in the outer region of the tubular water vapor separation membrane 3 in the casing of the water vapor separation device 2. In a state where the difference in partial pressure is always controlled, radioactive substances such as activated corrosion products contained in the water vapor in the reactor pressure vessel 24 do not permeate the water vapor separation membrane 3. For this reason, while confining the radioactive substance in the reactor pressure vessel 24, the water vapor passes through the water vapor separation membrane 3, passes through the water vapor discharge pipe 13 and the water vapor discharge pipe 17, and is discharged into the cooling water of the pressure suppression pool 28. The As described above, since the water vapor generated by the decay heat in the reactor pressure vessel 24 permeates the water vapor separation membrane 3 and is released into the pressure suppression pool 28, the pressure rise in the reactor pressure vessel 24 can be suppressed. it can. Since the water vapor that has passed through the water vapor separation membrane 3 does not contain a radioactive substance, contamination by radioactive substances on the inner surfaces of the water vapor discharge pipe 13, the isolation cooling system turbine 6 and the water vapor discharge pipe 17 is prevented. Further, water vapor that does not contain radioactive substances is discharged into the cooling water of the pressure suppression pool 28 through the water vapor discharge pipe 17. For this reason, the contamination by the radioactive material of the cooling water of the pressure suppression pool 28 and the inner surface of the pressure suppression chamber 27 is reduced.

  Also, since the isolation cooling system turbine 6 is driven by the water vapor that has passed through the water vapor separation membrane 3 and the isolation cooling system pump 7 is rotated, the cooling water 29A in the condensate storage tank 29 and the pressure suppression pool 28 are cooled. Water can be injected into the reactor pressure vessel 24 through the cooling water supply tube 22. The core fuel assembly in the reactor pressure vessel 24 is cooled by cooling water injected through the cooling water supply pipe 22. A drop in the water level in the reactor pressure vessel 24 due to the release of the water vapor in the reactor pressure vessel 24 to the pressure suppression pool 28 is prevented by the injection of cooling water into the reactor pressure vessel 24 by the cooling system pump 7 during isolation. The For this reason, the water level in the reactor pressure vessel 24 is maintained at a predetermined water level, and the fuel assembly in the core can be continuously cooled.

  Even when the turbine to which steam is supplied through the main steam pipe 30 trips, the isolation valves 31 and 32 are closed, so that, as described above, the discharge of water vapor that has passed through the water vapor separation membrane 3 in the water vapor treatment system 1, and The isolated cooling system turbine 6 is driven by the permeated water vapor, and the cooling water is injected into the reactor pressure vessel 24 by the isolated cooling system pump 7.

  A steam treatment system for a nuclear power plant according to embodiment 2, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  The steam treatment system 1A of the nuclear power plant of the present embodiment is configured such that the isolation cooling system turbine 6 and the isolation cooling system pump 7 are arranged in the cooling water 35 in the pool 33 in the steam treatment system 1 of the nuclear power plant of the first embodiment. It has the structure replaced with the condenser 34 made. The pool 33 is installed outside the reactor containment vessel 25 and is disposed above the reactor pressure vessel 24. One end portion of the steam discharge pipe 13 provided with the isolation valves 15 and 16 and penetrating the reactor containment vessel 25 is connected to the casing of the steam separation device 2 in the same manner as the steam treatment system 1, and each steam in the casing is connected. It communicates with a region outside the separation membrane 3. One end of the steam discharge pipe 13 is connected to a condenser 34. The condenser 34 has a plurality of heat transfer tubes (not shown), and the outer surfaces of these heat transfer tubes are in contact with the cooling water 35 in the pool 33. The condensed water supply pipe 22 </ b> A connected to the condenser 34 passes through the reactor containment vessel 25, passes through the dry well 26, and is connected to the reactor pressure vessel 24. The on-off valve 23 is provided in the dry well 26, and the feed water pump 36 and the on-off valve 37 are provided on the condensed water supply pipe 22A outside the reactor containment vessel 25, respectively. The other structure of the steam treatment system 1A is the same as that of the steam treatment system 1.

The casing of the steam separator 2 of the steam treatment system 1A has the same size as the casing of the steam separator 2 used in the first embodiment. The tubular water vapor separation membrane 3 installed in the casing of the water vapor separation device 2 in this embodiment is a kind of ceramic membrane, and is a tubular hollow fiber membrane having the same specifications as in the first embodiment. The total area of all the water vapor separation membranes 3 in the casing is 2119 m ² .

For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The steam generated by decay heat in the reactor pressure vessel 24 when the circulation pump 8 is driven passes through the main steam pipe 30 and the steam supply pipe 11, passes through the inlet header portion 5 in the steam separator 2, and has a tubular steam separation membrane. 3 is supplied. These steam separation membranes 3 are heated to 150 ° C. The water vapor in each water vapor separation membrane 3 passes through each water vapor separation membrane 3, reaches a region outside the water vapor separation membrane 3 in the casing, and is discharged to the water vapor discharge pipe 13. The water vapor permeation coefficient of the water vapor separation membrane 3 is 2 × 10 ⁻⁷ mol / s · m ² · Pa, the pressure inside the water vapor separation membrane 3 is 7.0 MPa, and the water vapor separation device 2 has a region outside the water vapor separation membrane 3. When the pressure is 4.5 MPa, the water vapor treatment capacity of the total water vapor separation membrane 3 of the water vapor separation device 2 is 70 t / h. The amount of water vapor that passes through each water vapor separation membrane 3 is adjusted by controlling the opening degree of the flow rate adjusting valve 14 provided in the water vapor discharge pipe 13. A part of the steam supplied to the steam separator 2 is discharged from each steam separation membrane 3 to the outlet header 4, and returned to the reactor pressure vessel 24 through the steam discharge pipe 9.

  The water vapor discharged to the water vapor discharge pipe 13 is guided into each heat transfer pipe of the condenser 34, cooled and condensed by the cooling water 35 in the pool 33, and becomes condensed water. The cooling water 35 in the pool 33 warmed by the condensation of water vapor becomes water vapor and is released to the atmosphere. When the water level of the cooling water 35 in the pool 33 is lowered to the set water level due to the atmospheric discharge of water vapor, the cooling water is supplied into the pool 33 from the makeup water system. Condensed water generated in each heat transfer tube of the condenser 34 is discharged to the condensed water supply tube 22 </ b> A and is injected into the reactor pressure vessel 24 by driving the feed water pump 36. Since the pressure in the reactor pressure vessel 24 is higher than the pressure 4.5 MPa in the steam discharge pipe 13, the condensed water is injected into the reactor pressure vessel 24 using the feed water pump 36.

  Except for the injection of the cooling water into the reactor pressure vessel 24 by the isolation cooling system pump 7, this embodiment can obtain each effect produced in the first embodiment. Specifically, it is possible to prevent contamination of the inner surfaces of the steam discharge pipe 13, the heat transfer pipes of the condenser 34, and the condensed water supply pipe 22A with radioactive substances. Further, since the condensed water generated in the condenser 34 is injected into the reactor pressure vessel 24, the cooling water in the reactor pressure vessel 24 is discharged by discharging the water vapor in the reactor pressure vessel 24 to the steam separator 2. The water level is prevented from lowering, and the fuel assembly in the core can be continuously cooled by injecting condensed water.

  A steam treatment system for a nuclear power plant according to embodiment 3, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  In the steam treatment system 1B of the nuclear power plant of the present embodiment, the isolation cooling system turbine 6, the isolation cooling system pump 7, and the cooling water supply pipes 18, 20, and 22 are deleted from the steam processing system 1 of the nuclear power plant of the first embodiment. The configuration is as follows. In the steam treatment system 1B, the steam discharge pipe 13 connected to the casing of the steam separator 2 is disposed in the reactor containment vessel 25, and the tip of the steam discharge pipe 13 is immersed in the cooling water of the pressure suppression pool 28. Yes. A relief safety valve 38 is provided in the water vapor supply pipe 11 instead of the on-off valve 12. The other structure of the steam treatment system 1B is the same as that of the steam treatment system 1. The steam separation device 2 of the steam treatment system 1B is disposed in the dry well 26 of the reactor containment vessel 25.

The casing of the steam separator 2 of the steam treatment system 1A has the same size as the casing of the steam separator 2 used in the first embodiment. The tubular water vapor separation membrane 3 installed in the casing of the water vapor separation device 2 in this embodiment is a kind of ceramic membrane, and is a tubular hollow fiber membrane having the same specifications as in the first embodiment. The total area of the tubular water vapor separation membrane 3 in the casing is 2119 m ² .

For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The water vapor separation membrane 3 is heated to 150 ° C. At this time, the reactor pressure vessel 24 is in a sealed state, and water vapor is generated by decay heat in the reactor pressure vessel 24, so that the pressure in the reactor pressure vessel 24 rises. When the pressure in the reactor pressure vessel 24 increases to an operation set pressure (7.5 to 8.0 MPa) or more of the relief safety valve 38, for example, 7.5 MPa, the relief safety valve 38 is opened, and the inside of the reactor pressure vessel 24 Of water vapor is discharged to the water vapor supply pipe 11 through the main steam pipe 30. The water vapor flows into the tubular water vapor separation membrane 3 through the inlet header portion 5 in the water vapor separation device 2 and permeates the water vapor separation membrane 3. The water vapor permeation coefficient of the water vapor separation membrane 3 is 2 × 10 ⁻⁷ mol / s · m ² · Pa, the pressure inside the water vapor separation membrane 3 is 7.5 MPa, and the water vapor separation device 2 has a region outside the water vapor separation membrane 3. When the pressure is 0.1 MPa (atmospheric pressure), the water vapor processing capacity of the total water vapor separation membrane 3 of the water vapor separation device 2 is 203 t / h. At this time, the flow rate of the water vapor passing through the water vapor separation membrane 3 is 0.033 m / s.

  When the pressure is released and the safety valve 38 is opened, the on-off valve 10 is opened and the circulation pump 8 is driven. A part of the water vapor that has not permeated through the water vapor separation membrane 3 passes through the outlet header 4 and the water vapor discharge pipe 9, is pressurized by the circulation pump 8, and is returned to the reactor pressure vessel 24. In order to prevent radioactive substances contained in the water vapor from accumulating inside the tubular water vapor separation membrane 3, the water vapor always flows inside the tubular water vapor separation membrane 3 by driving the circulation pump 8. The water vapor that has passed through the water vapor separation membrane 3 is discharged through the water vapor discharge pipe 13 into the cooling water of the pressure suppression pool 28 and condensed. When the pressure in the reactor pressure vessel 2 drops below the set pressure, the relief safety valve 38 is closed. At this time, the circulation pump 8 is stopped and the on-off valve 10 is also closed. When the pressure in the reactor pressure vessel 24 exceeds the set pressure due to water vapor generated by the decay heat, the relief safety valve 38 is opened.

  Since the water vapor that has passed through the water vapor separation membrane 3 is condensed in the pressure suppression pool 28, the pressure in the outer region of the tubular water vapor separation membrane 3 in the casing of the water vapor separation device 2 is maintained at an atmospheric pressure of approximately 0.1 MPa. The Further, even when the pressure in the reactor pressure vessel 24 decreases to 7.0 Mpa due to the permeation of the water vapor separation membrane 3, the water vapor separation membrane 3 is 189 t / h (flow rate 0.031 m / s). Water vapor generated by decay heat can be treated. When the water level in the reactor pressure vessel is lower than the set water level due to the release of the water vapor generated by the decay heat through the water vapor separation membrane 3 into the cooling water of the pressure suppression pool 28 by the water vapor discharge pipe 13, Until the water level in the reactor pressure vessel reaches the set water level, the cooling water in the pressure suppression pool 18 can be injected into the reactor pressure vessel 24 by a cooling water injection system (not shown).

  Except for the injection of the cooling water into the reactor pressure vessel 24 by the isolation cooling system pump 7, this embodiment can obtain each effect produced in the first embodiment. Specifically, it is possible to prevent the inner surface of the water vapor discharge pipe 13 from being contaminated with radioactive substances, and to reduce the pressure suppression pool 28 from being contaminated with radioactive substances. The steam treatment system 1B of the present embodiment is smaller than the steam treatment systems 1 and 1A because the isolation cooling system turbine 6, the isolation cooling system pump 7, the pool 33, and the condenser 34 are unnecessary.

  A steam treatment system for a nuclear power plant according to embodiment 4, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  The steam treatment system 1C of the nuclear power plant of the present embodiment has a configuration in which the steam discharge pipe 13 is opened to the dry well 26 in the steam treatment system 1B of the third embodiment. The water vapor separator 2 is disposed in the dry well 26. The water vapor discharge pipe 13 connected to the casing of the water vapor separator 2 does not extend to the pressure suppression pool 28 and is open to the dry well 26. The other structure of the steam treatment system 1C is the same as that of the steam treatment system 1B.

The casing of the steam separator 2 of the steam treatment system 1C has the same size as the casing of the steam separator 2 used in the first embodiment. The tubular water vapor separation membrane 3 installed in the casing of the water vapor separation device 2 in this embodiment is a kind of ceramic membrane, and is a tubular hollow fiber membrane having the same specifications as in the first embodiment. The total area of the tubular water vapor separation membrane 3 in the casing is 2119 m ² .

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The water vapor separation membrane 3 is heated to 150 ° C. When the pressure in the reactor pressure vessel 24 reaches the operation set pressure (9.0 MPa) of the relief valve 38 by the steam generated by the decay heat in the reactor pressure vessel 24, the relief safety valve 38 is opened, and the atom The steam in the furnace pressure vessel 24 is discharged to the steam supply pipe 11 through the main steam pipe 30. The water vapor flows into the tubular water vapor separation membrane 3 through the inlet header portion 5 in the water vapor separation device 2 and permeates the water vapor separation membrane 3. The pressure resistance of the reactor pressure vessel 24 is 9.0 MPa.

The water vapor permeation coefficient of the water vapor separation membrane 3 is 2 × 10 ⁻⁷ mol / s · m ² · Pa, the pressure inside the water vapor separation membrane 3 is 9.0 MPa, and the water vapor separation device 2 has a region outside the water vapor separation membrane 3. When the pressure is 0.1 MPa (atmospheric pressure), the water vapor treatment capacity of the total water vapor separation membrane 3 of the water vapor separation device 2 is 244 t / h. At this time, the flow rate of water vapor passing through the water vapor separation membrane 3 is 0.040 m / s.

  When the pressure is released and the safety valve 38 is opened, the on-off valve 10 is opened and the circulation pump 8 is driven. A part of the water vapor that has not permeated through the water vapor separation membrane 3 passes through the outlet header 4 and the water vapor discharge pipe 9, is pressurized by the circulation pump 8, and is returned to the reactor pressure vessel 24. In order to prevent radioactive substances contained in the water vapor from accumulating inside the tubular water vapor separation membrane 3, the water vapor always flows inside the tubular water vapor separation membrane 3 by driving the circulation pump 8.

  One end of each of a plurality of vent pipes (not shown) is open to the dry well 26. The other ends of these vent pipes are immersed in the cooling water of the pressure suppression pool. The water vapor that has passed through the water vapor separation membrane 3 is discharged to the dry well 26 through the water vapor discharge pipe 13. The water vapor discharged to the dry well 26 is discharged into the cooling water of the pressure suppression pool through each vent pipe and condensed by this cooling water.

  When the water level in the reactor pressure vessel is lower than the set water level due to the release of the water vapor generated by the decay heat through the water vapor separation membrane 3 into the cooling water of the pressure suppression pool 28 by the water vapor discharge pipe 13, Until the water level in the reactor pressure vessel reaches the set water level, the cooling water in the pressure suppression pool 18 can be injected into the reactor pressure vessel 24 by a cooling water injection system (not shown).

  Since the water vapor that has passed through the water vapor separation membrane 3 is condensed in the pressure suppression pool 28, the pressure in the outer region of the tubular water vapor separation membrane 3 in the casing of the water vapor separation device 2 is maintained at an atmospheric pressure of approximately 0.1 MPa. The Further, even when the pressure in the reactor pressure vessel 24 decreases to 7.0 Mpa due to the permeation of the water vapor separation membrane 3, the water vapor separation membrane 3 is 189 t / h (flow rate 0.031 m / s). Water vapor generated by decay heat can be treated.

  In the present embodiment, each effect produced in the third embodiment can be obtained. Since the water vapor discharged from the water vapor discharge pipe 13 to the dry well 26 does not contain a radioactive substance, the discharge of this water vapor can prevent contamination of equipment and piping disposed in the dry well 26 with the radioactive substance. . Moreover, it can reduce that the pressure suppression pool 28 from which the water vapor is released is contaminated with radioactive substances. Since the steam discharge pipe 13 is shortened, the steam treatment system 1C of this embodiment is further downsized than the steam treatment system 1B.

  A steam treatment system for a nuclear power plant according to embodiment 5, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  The steam treatment system 1D of the nuclear power plant of the present embodiment replaces the steam separation device 2 with the steam separation device 2A in the steam treatment system 1 of the first embodiment, and further uses the steam separation device 2A as cooling water in the reactor pressure vessel 24. It has the structure arrange | positioned in the dome area | region above the water surface. The steam separator 2 </ b> A does not form the inlet header part 5 and the outlet header part 4 unlike the steam separator 2. Both ends of a plurality of tubular water vapor permeable membranes 3 arranged in the casing of the water vapor separator 2A are attached to respective partition plates (not shown) corresponding to the tube plates provided facing the inside of the casing. . Therefore, both end portions of each water vapor permeable membrane 3 are open to the dry well 26, and each water vapor permeable membrane 3 is disposed between the pair of partition plates in the casing. The steam discharge pipe 13 connected to the casing of the steam separator 2 </ b> A passes through the reactor pressure vessel 24 and the reactor containment vessel 25 and is connected to the isolated cooling system turbine 6 arranged outside the reactor containment vessel 25. Has been. In the present embodiment, the heater for heating the water vapor separation membrane 3 is not attached to the casing of the water vapor separation device 2A. The other structure of the water vapor treatment system 1D is the same as that of the water vapor treatment system 1.

The tubular water vapor separation membrane 3 installed in the water vapor separation device 2A is a kind of ceramic membrane, and is a hollow fiber membrane having a thickness of 1.0 μm, a length of 1.0 m, and an outer diameter of 1 cm. The size of the casing (size between the pair of partition plates) of the water vapor separation device 2A in which the water vapor separation membranes 3 are bundled and arranged is 1.3 m in length, 1.3 m in width, and 1.0 m in height. Yes, the volume is 1.69 m ³ . The total area of all the water vapor separation membranes 3 in this casing is 1080 m ² .

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. When the isolation valves 31, 32 are closed, the on-off valves 15, 16, 19 are opened. The water vapor generated by decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 flows into each water vapor separation membrane 3 and permeates each water vapor separation membrane 3. The steam separation membrane 3 is heated to about 280 ° C. by steam. The water vapor that has passed through the tubular water vapor separation membrane 3 is formed between the pair of partition plates in the casing, reaches a region existing outside the water vapor separation membrane 3, and is discharged to the water vapor discharge pipe 13 connected to the casing. . The water vapor present in the dome region in the reactor pressure vessel 24 flows in the tubular water vapor separation membrane 3, and the radioactive substance contained in the water vapor is not deposited on the inner surface of the water vapor separation membrane 3. The amount of radioactive material contained in the water vapor in the dome region is very small compared to the amount of water vapor.

The water vapor permeation coefficient of the water vapor separation membrane 3 is 2 × 10 ⁻⁷ mol / s · m ² · Pa, the pressure inside the water vapor separation membrane 3 is 7.0 MPa, and the water vapor separation device 2A When the pressure is 2.0 MPa, the water vapor treatment capacity of the total water vapor separation membrane 3 of the water vapor separation device 2A is 70 t / h. At this time, the flow rate of water vapor passing through the water vapor separation membrane 3 is 0.022 m / s. The amount of water vapor that passes through each water vapor separation membrane 3 is adjusted by controlling the opening degree of the flow rate adjusting valve 14 provided in the water vapor discharge pipe 13. In the present embodiment, the opening degree of the flow rate adjusting valve 14 is adjusted so that the pressure in the water vapor discharge pipe 13 is equal to or higher than 1.1 MPa, which is the driving pressure of the isolation cooling system turbine 6.

  The steam discharged to the steam discharge pipe 13 drives the isolation cooling system turbine 6 and rotates the isolation cooling system pump 7. As a result, the cooling water 29A in the condensate storage tank 29 is injected into the reactor pressure vessel 24 as in the first embodiment. When the water level of the cooling water 29A in the condensate storage tank 29 drops to the set water level, the on-off valve 21 is opened and the on-off valve 19 is closed. Cooling water in the pressure suppression pool 28 is injected into the reactor pressure vessel 24.

  In the present embodiment, each effect produced in the first embodiment can be obtained. In this embodiment, the steam separator 2A can be made more compact than the steam separator 2 in the first embodiment. Further, since the water vapor separation membrane 3 can be heated at the temperature of the water vapor, it is not necessary to attach a heater to the casing of the water vapor separation device 2A. By disposing the steam separation device 2 in the reactor pressure vessel 24, it is not necessary to install the circulation pump 8 as in the first embodiment, and the steam processing system 1D becomes compact.

  A steam treatment system for a nuclear power plant according to embodiment 6, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  In the steam treatment system 1E of the nuclear power plant of the present embodiment, the steam separation device 2 in the steam treatment system 1A of the second embodiment is replaced with the steam separation device 2A used in the fifth embodiment, and the steam separation device 2A is replaced with a reactor pressure vessel. It has the structure arrange | positioned in the dome area | region above the water surface of the cooling water in 24. FIG. The configuration of the water vapor separation device 2A in the present embodiment is the same as that of the water vapor separation device 2A in the fifth embodiment. The steam discharge pipe 13 connected to the casing of the steam separator 2 </ b> A is connected to a condenser 34 that passes through the reactor pressure vessel 24 and the reactor containment vessel 25 and is arranged outside the reactor containment vessel 25. Yes. Other configurations of the steam treatment system 1E are the same as those of the steam treatment system 1A.

The tubular water vapor separation membrane 3 installed in the water vapor separation device 2A used in the present embodiment is a kind of ceramic membrane, and is a hollow fiber membrane having the same specifications as in the fifth embodiment. The size of the casing of the water vapor separation device 2A in the present embodiment in which the water vapor separation membranes 3 are bundled and arranged is the same as that in the fifth embodiment, and the volume is 1.69 m ³ . The total area of all the water vapor separation membranes 3 in this casing is 1080 m ² .

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. At this time, the on-off valves 15, 16, 23, and 37 are opened. The water vapor generated by the decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 flows into each water vapor separation membrane 3 heated to about 280 ° C., and each water vapor separation membrane 3 Transparent. The water vapor that has passed through the water vapor separation membrane 3 is discharged to the water vapor discharge pipe 13.

The water vapor permeation coefficient of the water vapor separation membrane 3 is 2 × 10 ⁻⁷ mol / s · m ² · Pa, the pressure inside the water vapor separation membrane 3 is 7.0 MPa, and the water vapor separation device 2A When the pressure is 2.0 MPa, the water vapor treatment capacity of the total water vapor separation membrane 3 of the water vapor separation device 2A is 70 t / h. At this time, the flow rate of water vapor passing through the water vapor separation membrane 3 is 0.022 m / s.

  The water vapor discharged to the water vapor discharge pipe 13 is guided into each heat transfer pipe of the condenser 34, cooled and condensed by the cooling water 35 in the pool 33, and becomes condensed water. The condensed water is injected into the reactor pressure vessel 24 through the condensed water supply pipe 22 </ b> A by driving the feed water pump 36.

  In the present embodiment, each effect produced in the second embodiment can be obtained. In this embodiment, the steam separator 2A can be made more compact than the steam separator 2 in the first embodiment. Further, since the water vapor separation membrane 3 can be heated at the temperature of the water vapor, it is not necessary to attach a heater to the casing of the water vapor separation device 2A.

  A steam treatment system for a nuclear power plant according to embodiment 7, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  In the steam treatment system 1F of the nuclear power plant of the present embodiment, the steam separator 2 in the steam treatment system 1B of the third embodiment is replaced with the steam separator 2A used in the fifth embodiment, and the steam separator 2A is replaced with a reactor pressure vessel. It has the structure arrange | positioned in the dome area | region above the water surface of the cooling water in 24. FIG. The configuration of the water vapor separation device 2A in the present embodiment is the same as that of the water vapor separation device 2A in the fifth embodiment. The water vapor discharge pipe 13 connected to the casing of the water vapor separator 2 </ b> A is disposed in the reactor containment vessel 25, and the front end of the water vapor discharge pipe 13 is immersed in the cooling water of the pressure suppression pool 28. A relief safety valve 39 is provided in the water vapor discharge pipe 13. The other structure of the steam treatment system 1F is the same as that of the steam treatment system 1B.

The tubular water vapor separation membrane 3 installed in the water vapor separation device 2A used in the present embodiment is a kind of ceramic membrane, and is a hollow fiber membrane having the same specifications as in the fifth embodiment. The size of the casing of the water vapor separation device 2A in the present embodiment in which the water vapor separation membranes 3 are bundled and arranged is the same as that in the fifth embodiment, and the volume is 1.69 m ³ . The total area of all the water vapor separation membranes 3 in this casing is 1080 m ² .

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The water vapor generated by the decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 flows into each water vapor separation membrane 3 heated to about 280 ° C., and each water vapor separation membrane 3 Transparent. The water vapor that has passed through the water vapor separation membrane 3 is discharged to the water vapor discharge pipe 13. Since the pressure upstream of the safety relief valve 39 in the water vapor discharge pipe 13 is less than 7.5 MPa, the safety relief valve 39 whose operation set pressure is 7.5 to 8.0 MPa is closed. Due to the permeation of water vapor through the water vapor separation membrane 3, the pressure upstream of the relief safety valve 39 in the water vapor discharge pipe 13 gradually increases. As the pressure of the steam discharge pipe 13 on the upstream side of the relief safety valve 39 increases, the amount of steam that permeates the steam separation membrane 3 decreases, and the pressure in the reactor pressure vessel 24 also increases. When the water vapor permeates through the water vapor separation membrane 3 and the pressure on the upstream side of the water discharge pipe 13 from the safety valve 39 becomes 7.5 MPa, which is the operating set pressure of the safety valve 39, the safety relief valve 39 is When opened, the steam that exists upstream of the relief safety valve 39 in the steam discharge pipe 13 passes through the relief safety valve 39 that is opened, and is discharged into the cooling water of the pressure suppression pool 28 and condensed. As a result, the pressure upstream of the relief valve 39 in the water vapor discharge pipe 13 becomes less than 7.5 MPa, which is the operation set pressure, and the relief valve 39 is closed. When the pressure on the upstream side of the relief safety valve 39 of the steam exhaust pipe 13 becomes 7.5 MPa, which is the operation set pressure, due to the permeation of the steam through the steam separation membrane 3, the relief safety valve 39 opens and the steam exhaust pipe 13, water vapor existing upstream from the relief safety valve 39 is released into the cooling water of the pressure suppression pool 28. In this way, the closed state and the open state of the relief safety valve 39 are repeated, and the discharge stop and start of discharge of the water vapor transmitted through the water vapor separation membrane 3 into the cooling water of the pressure suppression pool 28 are repeated.

  When the internal pressure of the reactor pressure vessel 24 is 7.5 MPa and the relief safety valve 39 is activated, the water vapor treatment capacity of the water vapor separation device 3 of the water vapor separation device 2 is 104 t / h (the water vapor separation membrane in the water vapor separation device 2). 3 is 0.1 MPa), and the internal pressure of the reactor pressure vessel 24 is reduced to 7.0 MPa and the relief valve 39 is closed immediately before the safety valve 39 is closed. The processing capacity is 70 t / h (the pressure in the outer region of the water vapor separation membrane 3 in the water vapor separator 2 is 0.1 MPa).

  This embodiment can obtain the effects produced in the fifth embodiment. Since the isolation cooling system turbine 6, the isolation cooling system pump 7, the pool 33, and the condenser 34 are unnecessary, the steam treatment system 1B of this embodiment is made smaller than the steam treatment systems 1D and 1E. In this embodiment, the steam separator 2A can be made more compact than the steam separator 2 in the first embodiment. Further, since the water vapor separation membrane 3 can be heated at the temperature of the water vapor, it is not necessary to attach a heater to the casing of the water vapor separation device 2A.

  An opening / closing valve may be provided in the water vapor discharge pipe 13 instead of the relief safety valve 39. This on-off valve is closed when the boiling water nuclear plant is normally operated and the pressure in the reactor pressure vessel 24 is maintained at the set pressure, and after the boiling water nuclear plant is stopped, the decay heat When the pressure in the reactor pressure vessel 24 exceeds the set pressure due to the water vapor generated by the above, the on-off valve is automatically or manually opened. As a result, the water vapor in the reactor pressure vessel 24 is guided to the water vapor separation device 2 </ b> A, passes through the water vapor separation membrane 3, and is released into the cooling water in the pressure suppression pool 28.

  A steam treatment system for a nuclear power plant according to embodiment 8, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  In the steam treatment system 1G of the nuclear power plant of this embodiment, in the steam treatment system 1C of the fourth embodiment, the steam separator 2 is replaced with the steam separator 2A used in the fifth embodiment, and the steam separator 2A is replaced with a reactor pressure vessel. It has the structure arrange | positioned in the dome area | region above the water surface of the cooling water in 24. FIG. The configuration of the water vapor separation device 2A in the present embodiment is the same as that of the water vapor separation device 2A in the fifth embodiment.

The tubular water vapor separation membrane 3 installed in the water vapor separation device 2A used in the present embodiment is a kind of ceramic membrane, and is a hollow fiber membrane having the same specifications as in the fifth embodiment. The size of the casing of the water vapor separation device 2A in the present embodiment in which the water vapor separation membranes 3 are bundled and arranged is the same as that in the fifth embodiment, and the volume is 1.69 m ³ . The total area of all the water vapor separation membranes 3 in this casing is 1080 m ² .

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The water vapor generated by the decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 flows into each water vapor separation membrane 3 heated to about 280 ° C., and each water vapor separation membrane 3 Transparent. The water vapor that has passed through the water vapor separation membrane 3 is discharged to the water vapor discharge pipe 13. Since the pressure upstream of the safety relief valve 39 in the water vapor discharge pipe 13 is less than 9.0 MPa, the safety relief valve 39 whose operation set pressure is 9.0 MPa is closed. Due to the permeation of water vapor through the water vapor separation membrane 3, the pressure upstream of the relief safety valve 39 in the water vapor discharge pipe 13 gradually increases. As the pressure of the steam discharge pipe 13 on the upstream side of the relief safety valve 39 increases, the amount of steam that permeates the steam separation membrane 3 decreases, and the pressure in the reactor pressure vessel 24 also increases. When the pressure in the reactor pressure vessel 24 becomes 9.0 MPa, the pressure on the upstream side of the relief valve 39 of the steam discharge pipe 13 becomes 9.0 MPa, and the relief valve 39 opens. Water vapor existing upstream of the safety relief valve 39 in the water vapor discharge pipe 13 passes through the safety relief valve 39 and is discharged to the dry well 26. As a result, the pressure upstream of the safety relief valve 39 in the steam discharge pipe 13 becomes less than 9.0 MPa, which is the operation set pressure, and the safety relief valve 39 is closed. When the pressure on the upstream side of the relief safety valve 39 in the steam discharge pipe 13 becomes 9.0 MPa due to the permeation of the steam through the steam separation membrane 3 as the pressure in the reactor pressure vessel 24 increases, the relief safety valve 39 Is opened, and water vapor existing upstream of the safety relief valve 39 in the water vapor discharge pipe 13 is released into the dry well 26. As described above, the closed state and the open state of the relief safety valve 39 are repeated, and the release stop and start of release of the water vapor that has passed through the water vapor separation membrane 3 to the dry well 26 are repeated.

  The water vapor discharged from the water vapor discharge pipe 13 to the dry well 26 is discharged into the cooling water of the pressure suppression pool 28 through the vent pipe and condensed as in the fourth embodiment.

  In the present embodiment, the water vapor is processed at 97 t / h by the water vapor separation membrane 3.

  This embodiment can obtain the effects produced in the fifth embodiment. Since the steam discharge pipe 13 is shortened, the steam processing system 1G of the present embodiment is further downsized than the steam processing system 1F. In this embodiment, the steam separator 2A can be made more compact than the steam separator 2 in the first embodiment. Further, since the water vapor separation membrane 3 can be heated at the temperature of the water vapor, it is not necessary to attach a heater to the casing of the water vapor separation device 2A.

  A steam treatment system for a nuclear power plant according to embodiment 9, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  The steam treatment system 1H of the nuclear power plant of the present embodiment has a configuration in which an iodine gas trap (iodine gas removal device) 40 is added to the steam treatment system 1 of the first embodiment. The iodine gas trap 40 is disposed upstream of the inlet header 5 and is installed in the casing of the water vapor separator 2. The water vapor supply pipe 11 is connected to the iodine gas trap 40, and the iodine gas trap 40 communicates with the inlet header portion 5. The other structure of the steam treatment system 1H is the same as that of the steam treatment system 1 of the first embodiment. The iodine gas trap 40 may be provided in the steam supply pipe 11 without being installed in the casing of the steam separator 2.

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. The steam generated by decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 is supplied to the iodine gas trap 40 through the main steam pipe 30 and the steam supply pipe 11. The iodine contained in the water vapor is removed by the iodine gas trap 40, and the water vapor from which the iodine has been removed is supplied into the tubular hydrogen gas separation membrane 3 in the water vapor separation device 2 through the inlet header portion 5.

  Water vapor treatment by the water vapor treatment system 1H is performed in the same manner as the water vapor treatment system 1. For this reason, description of the process of the water vapor in the water vapor treatment system 1H is omitted here. In the present embodiment, each effect produced in the first embodiment can be obtained. By installing the iodine gas trap 40, the water vapor separation membrane 3 can be prevented from being deteriorated, and the water vapor transmission performance of the water vapor separation device 2 can be prevented from being lowered.

  A steam treatment system for a nuclear power plant according to embodiment 10, which is another preferred embodiment of the present invention, will be described with reference to FIG. The steam treatment system for a nuclear power plant of this embodiment is applied to a boiling water nuclear power plant.

  The steam treatment system 1I of the nuclear power plant of the present embodiment has a configuration in which iodine gas traps (iodine gas removal devices) 40 and 40A are added to the steam treatment system 1D of the fifth embodiment. The iodine gas trap 40 is attached to the casing of the water vapor separation device 2A so as to face one end of each tubular water vapor separation membrane 3 in the water vapor separation device 2A. The iodine gas trap 40A is attached to the casing of the water vapor separation device 2A so as to face the other end of each tubular water vapor separation membrane 3 in the water vapor separation device 2A. The other structure of the steam treatment system 1I is the same as that of the steam treatment system 1D.

  For example, when the operation of the boiling water nuclear plant in one operation cycle is completed and the boiling water nuclear plant is stopped, or when a turbine trip occurs, the isolation valves 31 and 32 are fully closed. Water vapor generated by decay heat in the reactor pressure vessel 24 and reaching the dome region in the reactor pressure vessel 24 is supplied to iodine gas traps 40 and 40A. The iodine contained in the water vapor is removed by the iodine gas traps 40, 40 A, and the water vapor from which the iodine has been removed is supplied into the tubular hydrogen gas separation membrane 3 in the water vapor separation device 2.

  Water vapor treatment by the water vapor treatment system 1I is performed in the same manner as the water vapor treatment system 1D. For this reason, description of the process of the water vapor in the water vapor treatment system 1H is omitted here. In the present embodiment, each effect produced in the fifth embodiment can be obtained. Moreover, since the iodine gas traps 40 and 40A are installed, the water vapor separation membrane 3 can be prevented from being deteriorated as in the ninth embodiment.

  1, 1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1I ... Steam treatment system, 2, 2A ... Steam separation device, 3 ... Steam separation membrane, 4 ... Outlet header, 5 ... Inlet header, 6 ... Isolation cooling turbine, 7 ... Isolation cooling system pump, 13 ... Steam discharge pipe, 24 ... Reactor pressure vessel, 25 ... Reactor containment vessel, 26 ... Drywell, 27 ... Pressure suppression chamber, 28 ... Pressure Suppression pool, 29 ... condensate storage tank, 33 ... pool, 34 ... condenser, 40, 40A ... iodine gas trap.

Claims (7)

  A plurality of annular steam separation membranes arranged in a dry well in a reactor containment vessel that surrounds the reactor pressure vessel, communicated with the reactor pressure vessel, and transmit water vapor generated in the reactor pressure vessel inside And a steam discharge pipe connected to the steam separator and exhausting the steam permeated through the steam separation membrane to the outside of the steam separator. Steam treatment system.   An annular structure that is disposed above the surface of the cooling water in the reactor pressure vessel surrounded by the reactor containment vessel, is opened to the reactor pressure vessel, and allows water vapor generated in the reactor pressure vessel to pass therethrough. A water vapor separator that houses a plurality of water vapor separation membranes, and water vapor that is connected to the water vapor separation device and exhausts the water vapor that has permeated through the water vapor separation membrane to the outside of the reactor pressure vessel outside the water vapor separation device A steam treatment system for a nuclear power plant comprising an exhaust pipe.   The steam treatment of a nuclear power plant according to claim 1 or 2, further comprising an iodine removal device that is disposed upstream of the steam separation device, communicates with the steam separation device, and through which water vapor generated in the reactor pressure vessel passes. system.   The steam discharge pipe is connected to an isolation cooling system turbine disposed outside the reactor containment vessel, and the pressure at which another steam discharge pipe connected to the isolation cooling system turbine is formed in the containment vessel The isolation cooling system pump reaches the suppression pool, the isolation cooling system pump is connected to the isolation cooling system turbine, and the cooling water supply pipe for guiding the cooling water discharged from the isolation cooling system pump is connected to the reactor pressure vessel A steam treatment system for a nuclear power plant according to claim 1 or 2.   The water vapor discharge pipe is connected to a condenser in a pool disposed outside the reactor containment vessel, and is led by the water vapor discharge pipe to lead the condensed water generated by the condenser. The steam treatment system for a nuclear power plant according to claim 1 or 2, wherein is connected to the reactor pressure vessel.   The steam treatment system for a nuclear power plant according to claim 1 or 2, wherein the steam discharge pipe reaches a pressure suppression pool formed in the reactor containment vessel.   The steam treatment system for a nuclear power plant according to claim 1 or 2, wherein the steam discharge pipe is opened to a dry well in the reactor containment vessel.

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