JP2011058895A - Nuclear reactor containment facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nuclear reactor containment facility reducing a concentration of combustible gas in a short time. <P>SOLUTION: A first PCV3 covered by a second PCV15 forms a first pressure suppression chamber 7 including therein a dry well 6, an inside pressure suppression pool 8, and an inside wet well 9. Between the first PCV3 and the second PCV15, a second pressure suppression chamber 16 and an equipment installation area 20 are formed at respective lower and upper parts of a partition floor 17. The second pressure suppression chamber 16 has an outside pressure suppression pool 25 that is in communication with the inside pressure suppression pool 8 and an outside wet well 26 that is in communication with the wet well 9. A plurality of opening parts 18 that are closed with a rupture disk 19 and communicate the outside wet well 26 with the equipment installation area 20 are formed in the partition floor 17. The volume of the equipment installation area 20 is 75% or more and 120% or less of the total volume of the wet wells. A plurality of catalyst type combustible gas processing devices 27 are arranged in the equipment installation area 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reactor containment facility, and more particularly to a reactor containment facility suitable for application to a boiling water nuclear power plant.

  In a nuclear power plant, a primary reactor containment vessel covering a reactor pressure vessel, a steel secondary reactor containment vessel covering the primary reactor containment vessel, and an outer vessel surrounding the secondary reactor containment vessel A reactor containment facility with

  An example of this reactor containment facility is described in Japanese Patent Application Laid-Open No. 2004-85234. The natural heat radiation type reactor containment facility described in Japanese Patent Application Laid-Open No. 2004-85234 includes a primary reactor containment vessel, a steel secondary reactor containment vessel covering the primary reactor containment vessel, and concrete. Having an external container. The primary reactor containment vessel has a concrete part having a pressure resistance function and a liner having an airtight function covering the inner surface of the concrete part. In the primary reactor containment vessel, a dry well and a pressure suppression chamber isolated by a diaphragm floor are formed. The pressure suppression chamber has a pressure suppression pool and a wet well formed above the surface of the cooling water in the pressure suppression pool. The reactor pressure vessel is installed on the pedestal installed in the primary reactor containment vessel, and is arranged in the dry well.

  A partition floor is attached to the primary reactor containment vessel and the secondary reactor containment vessel, and is disposed at substantially the same height as the diaphragm floor. A pool communicating with the pressure suppression pool is formed below the partition floor. This pool is also filled with cooling water. An opening is formed in the partition floor, and this opening is sealed with a rupture disk. An equipment installation area is formed between the primary reactor containment vessel and the secondary reactor containment vessel above the partition floor.

  The fuel storage pool, the equipment temporary storage pool, and the reactor well are disposed in the secondary reactor containment vessel and above the primary reactor containment vessel. An operation floor area is formed in the secondary reactor containment above the fuel storage pool, the equipment temporary pool and the reactor well. This operation floor area is connected to the equipment installation area. An outer peripheral pool filled with cooling water is formed between the secondary reactor containment vessel and the outer vessel.

  When the main steam pipe connected to the reactor pressure vessel breaks and a coolant loss accident occurs, high-temperature steam is discharged from the broken portion of the main steam pipe into the dry well. This steam is discharged into the cooling water in the pressure suppression pool and condensed. Thereby, the pressure rise in the dry well is reduced. The temperature of the cooling water in the pressure suppression pool rises due to the condensation of steam, but is transmitted to the cooling water in the outer peripheral pool through the steel secondary reactor containment vessel. As a result, the cooling water in the pressure suppression pool is cooled by the cooling water in the outer peripheral pool, and the temperature rise is suppressed. The cooling water in the outer peripheral pool becomes steam by the heating and is discharged out of the external container.

  In the reactor containment facility described in Japanese Patent Application Laid-Open No. 2004-85234, the pressure of the wet well in the pressure suppression chamber where non-condensable gas is accumulated above the coolant level of the pressure suppression pool rises above the set pressure. In this case, the rupturable plate provided on the partition floor is ruptured, and the gas in the wet well is released to the equipment installation area and the operation floor area. By releasing this gas, the pressure rise in the wet well is suppressed.

  Japanese Patent Application Laid-Open No. 8-334585 also describes a natural heat radiation type reactor containment facility. This reactor containment facility is also a secondary reactor made of steel covering the primary reactor containment vessel and the primary reactor containment vessel, similar to the reactor containment facility described in JP-A-2004-85234. A containment vessel and a concrete outer vessel. The reactor containment facility described in JP-A-8-334585 is not provided with a partition floor as in JP-A-2004-85234, but between the primary reactor containment vessel and the secondary reactor containment vessel. In the passage connecting the gas space in the wet well and the operation floor area, a rupturable plate is provided at the bottom of the fuel storage pool, and the primary reactor containment vessel and the secondary are located above the rupturable plate. A hydrogen reaction facility is installed between the reactor containment vessels.

  In a nuclear power plant, it is required to ensure safety by a containment facility even if a severe accident with a very low probability of occurrence occurs. When a severe accident occurs, a large amount of hydrogen is generated by the reaction of the zirconium alloy that forms the cladding tube of the fuel rod included in the fuel assembly loaded on the core in the reactor pressure vessel and water. Such a large amount of hydrogen cannot be processed by the existing combustible gas concentration control system and emergency gas processing system. For this reason, in the reactor containment facility described in JP-A-8-334585, a hydrogen reaction facility is installed in the secondary reactor containment vessel. A large amount of hydrogen generated in a severe accident is released from the dry well into the pressure suppression pool and is accumulated in the wet well. When the pressure in the wet well exceeds the set pressure, the rupturable plate bursts and the hydrogen gas in the gas space is placed in the hydrogen reaction facility installed between the primary reactor containment vessel and the secondary reactor containment vessel. Led to. The hydrogen reaction facility reacts hydrogen with oxygen to produce water, thereby reducing the hydrogen concentration. Thereby, the pressure and hydrogen concentration in the primary reactor containment vessel are reduced.

  Japanese Patent Laid-Open No. 10-227885 discloses that a combustible gas concentration reducing device is disposed in a dry well and a wet well of a reactor containment vessel. In this combustible gas concentration reducing device, a catalyst is disposed in the chimney. When a coolant loss accident occurs, steam containing hydrogen and oxygen is released from the breakage point into the dry well of the reactor containment vessel. Hydrogen and oxygen flow into the chimney and are combined into water by the action of the catalyst. Thus, the concentration of the combustible gas (hydrogen) in the dry well is reduced by the combustible gas concentration reducing device.

JP 2004-85234 A JP-A-8-334585 Japanese Patent Laid-Open No. 10-227885

  In the reactor containment facility described in JP-A-8-334585, a large amount of hydrogen generated during a severe accident is led to the hydrogen reaction facility by the rupture of the rupturable plate and combined with oxygen to produce water. In this way, the generated hydrogen is processed to reduce the hydrogen concentration.

  However, as a result of detailed examination of the reactor containment facility described in Japanese Patent Application Laid-Open No. 8-334585, the inventor found that the hydrogen reaction facility was placed in a narrow space in the secondary reactor containment vessel. Since it was installed, it was discovered that there is a new problem that it takes time to reduce the hydrogen concentration.

  An object of the present invention is to provide a reactor containment facility capable of reducing the concentration of combustible gas in a short time.

The feature of the present invention that achieves the above-described object is that the first pressure suppression chamber formed in the primary reactor containment vessel has a first pressure suppression pool filled with cooling water, and cooling of the first pressure suppression pool A first spatial region formed above the water surface;
A partition floor disposed between the primary reactor containment vessel and the secondary reactor containment vessel covering the primary reactor containment vessel is installed in the primary reactor containment vessel and the secondary reactor containment vessel,
A second pressure suppression pool that communicates with the first pressure suppression pool and is filled with cooling water, and a second space region that is formed above the cooling water level of the second pressure suppression pool and communicates with the first space region. A second pressure suppression chamber is formed between the primary reactor containment vessel and the secondary reactor containment vessel below the partition floor,
An equipment installation area is formed between the primary reactor containment vessel and the secondary reactor containment vessel above the partition floor,
When the rupture disc is ruptured by being blocked by the rupture disc, a plurality of openings that connect the second space region and the device installation area are formed in the partition floor,
Multiple flammable gas treatment devices are communicated to the equipment installation area,
The volume of the space in the device installation area is in the range of 75% to 120% of the total volume of the volume of the first space area and the volume of the second space area.

  The volume of the space in the equipment installation area is in the range of 75% to 120% of the total volume of the first space area and the second space area, and a plurality of combustibles communicated with the equipment installation area. By providing the combustible gas processing apparatus, hydrogen released together with the vapor in the dry well at the time of an accident can be efficiently processed by the combustible gas processing apparatus. For this reason, the concentration of hydrogen released into the primary reactor containment vessel can be reduced in a short time.

  ADVANTAGE OF THE INVENTION According to this invention, the density | concentration of the combustible gas discharge | released in a primary reactor containment vessel at the time of an accident can be reduced in a short time.

1 is a longitudinal sectional view of a reactor containment facility that is a preferred embodiment of the present invention. FIG. 2 is an enlarged longitudinal sectional view of the catalytic combustible gas treatment device shown in FIG. 1. It is a characteristic view which shows the time change of the pressure in each part at the time of a severe accident in the reactor containment equipment which has not installed the catalyst type combustible gas processing apparatus. It is a characteristic view which shows the time change of the hydrogen gas density | concentration in each part at the time of a severe accident in the nuclear reactor containment equipment which has not installed the catalyst type combustible gas processing apparatus. Shows changes in hydrogen gas concentration over time in severe accidents when the installation position and number of bases of a catalytic combustible gas treatment device is changed in a reactor containment facility where a catalytic combustible gas treatment device is installed. FIG. It is a characteristic view which shows the time change of the hydrogen gas weight in each part by the installation position of a catalyst type combustible gas processing apparatus in the reactor containment equipment which installed the catalyst type combustible gas processing apparatus. It is a characteristic view which shows the time change of hydrogen gas processing amount when the installation position of a catalyst type combustible gas processing apparatus is changed in the reactor containment equipment which installed the catalyst type combustible gas processing apparatus. It is a characteristic view which shows the time change of hydrogen gas processing amount when the volume of an apparatus installation area is changed in the reactor containment installation which installed the catalyst type combustible gas processing apparatus. It is a characteristic view which shows the time change of the hydrogen concentration of an equipment installation area when the volume of an equipment installation area is changed in the reactor containment equipment which installed the catalyst type combustible gas processing apparatus. FIG. 7 is a characteristic diagram showing the influence of the volume of the hydrogen gas processing amount on the equipment installation area when the elapsed time after the rupture plate burst is used as a parameter in the reactor containment facility where the catalytic combustible gas treatment device is installed. .

  In the reactor containment facility described in Japanese Patent Application Laid-Open No. 8-334585, the hydrogen reaction facility is formed between the primary reactor containment vessel and the secondary reactor containment vessel as described above. It is installed in the passage connecting the driving floor area. The region where the hydrogen reaction facility is installed is very narrow because the primary reactor containment vessel is approaching the secondary reactor containment vessel. The inventors have installed a hydrogen reaction facility in such a narrow region, so that hydrogen in the region is processed by the hydrogen reaction facility and the hydrogen concentration in the region is reduced, so that the hydrogen in the region is reduced. It has been found that a new problem arises that the hydrogen treatment efficiency of the hydrogen reaction facility is lowered even when the hydrogen concentration in the wet well is high because it becomes too small. For this reason, it takes a long time to reduce the hydrogen concentration in the primary reactor containment vessel.

  Therefore, the inventors have come up with the idea that a combustible gas treatment device may be installed in the equipment installation area above the partition floor in the reactor containment facility described in Japanese Patent Application Laid-Open No. 2004-85234. And the inventors examined the process of the hydrogen which is a combustible gas by the catalyst-type combustible gas processing apparatus installed in the apparatus installation area. The result of this examination will be described below.

  FIG. 3 shows changes in the pressures of the wet well, the device installation area, and the operation floor area with the passage of time from the time of rupture of the rupturable plate when no catalytic combustible gas treatment device is installed in the device installation area. The pressure in the wet well that has risen due to the occurrence of a severe accident decreases after the rupture disc has ruptured, and the degree of decrease decreases after about 15 minutes have elapsed since the rupture point. Each pressure in the equipment installation area and the operation floor area increases as the pressure in the wet well decreases. Each pressure in the equipment installation area and the operation floor area changes in the same manner and shows the same value. When it is simply referred to as a wet well, a first space region (described later) formed above the cooling water level of the first pressure suppression pool in the first pressure suppression chamber formed in the primary reactor containment vessel. The inner wet well 9) and the second pressure suppression in the second pressure suppression chamber formed between the primary reactor containment vessel and the secondary reactor containment vessel covering the primary reactor containment vessel It means a region where both of the second space regions (outer wet wells 26 in the embodiments described later) formed above the cooling water surface of the pool are combined.

  FIG. 4 shows changes in the hydrogen concentrations of the wet well, the equipment installation area, and the operation floor area with the passage of time from the rupture point of the rupture disk when no catalytic combustible gas treatment device is installed in the equipment installation area. . Due to the occurrence of a severe accident, the hydrogen concentration in the wet well is high. After the rupture disc ruptures, the hydrogen concentration in the wet well decreases. Each hydrogen concentration in the equipment installation area and the operation floor area rises after the rupture disc ruptures. The degree of increase in the hydrogen concentration in the equipment installation area is larger than that in the operation floor area. That is, the hydrogen concentration in the equipment installation area and the operation floor area, which was 0 before the rupture disk burst, increases as the rupture disk ruptures, whereas the wet well hydrogen concentration decreases. . The increase in the hydrogen concentration in the equipment installation area where the hydrogen released from the wet well directly flows in is remarkable, which is 4 to 5 times the hydrogen concentration in the operation floor area. This is because the gas mixture having a high hydrogen concentration released from the wet well where hydrogen has accumulated directly flows into the equipment installation area, and furthermore, the degree of dilution of the hydrogen gas in the equipment installation area is small. It is. This state is maintained while hydrogen gas flows into the equipment installation area through the ruptured rupture disc. During this time, the hydrogen concentration in the equipment installation area is higher than the hydrogen concentration in the operation floor area.

  3 and 4 show the analysis results on the behavior of pressure and hydrogen concentration during severe accidents. The severe accidents targeted for analysis assumed the failure of the main steam pipe and water injection into the core. In this analysis, the volume of the space in the equipment installation area (the volume obtained by subtracting the volume of the equipment and piping installed in the equipment installation area from the total volume in the equipment installation area) is defined as 113% of the volume of the wet well. Yes. These analyzes were performed using MAAP codes for evaluating severe accidents in nuclear power plants as analysis codes. The MAAP code is introduced in documents such as “http://www.meti.go.jp/report/downloadfiles/g21206bj.pdf”. The analysis results shown in FIGS. 5 to 10 described later are also obtained using the MAAP code. The volume of the wet well is the volume of the first space region (inner wet well 9 in the embodiment described later) formed above the cooling water level of the first pressure suppression pool in the first pressure suppression chamber. And the total volume of the second space region (outer wet well 26 in the examples described later) formed above the coolant surface of the second pressure suppression pool in the second pressure suppression chamber.

  The inventors of the present invention have the primary reactor containment vessel and the secondary reactor containment when the catalytic combustible gas treatment device is disposed between the primary reactor containment vessel and the secondary reactor containment vessel above the partition floor. Changes in the hydrogen concentration between the containers after the rupturable plate burst were analyzed using the MAAP code. The analysis results are shown in FIG. As a result of this analysis, the first case in which two catalytic combustible gas treatment devices are arranged in the equipment installation area, and one catalytic combustible gas treatment device is arranged in the equipment installation area. It has shown about the 2nd case which has arrange | positioned the catalyst type combustible gas processing apparatus in the operation floor area. In addition, the change of each pressure of the wet well, an apparatus installation area, and an operation floor area in a 1st case and a 2nd case is the same as FIG. This is because the amount of hydrogen treated by the catalytic combustible gas treatment device is relatively small relative to the total amount of gas including air and water vapor.

  When the analysis result shown in FIG. 5 is compared with the analysis result shown in FIG. 4, as is clear from FIG. 5, the hydrogen concentration in the area where the catalytic combustible gas treatment device is installed is lowered. The hydrogen concentration in the equipment installation area is maintained higher than the hydrogen concentration in the operation floor area in both the first and second cases. The change in hydrogen concentration in the wet well and the operation floor area is substantially the same in the first case and the second case. In addition, the hydrogen concentration in the device installation area is lower in the first case than in the second case. During operation of the nuclear power plant, nitrogen gas is present in the wet well, and air is present in the equipment installation area and the operation floor area. The hydrogen concentrations in the wet well, the equipment installation area, and the operation floor area described above are the hydrogen concentrations when the gas (for example, nitrogen gas, air) existing in each region is taken into account after the rupture plate is ruptured. .

  FIG. 6 shows the change of the weight of hydrogen gas existing in each area with the passage of time from the rupture point of the rupture disk in each of the two cases shown in FIG. 5, that is, the first and second cases. In addition, the hydrogen gas weight in FIG. 6 is normalized by the weight of the hydrogen gas existing in the wet well before the rupture plate bursts. In the equipment installation area, the hydrogen gas weight of the first case is smaller than the hydrogen gas weight of the second case. In the operation floor area, the hydrogen gas weight of the second case is smaller than the hydrogen gas weight of the first case.

  FIG. 7 shows the amount of hydrogen treated by the catalytic combustible gas treatment apparatus for the first and second cases. The amount of hydrogen treatment shown in FIG. 7 is normalized by the weight of hydrogen gas present in the wet well before the rupture plate bursts, as in FIG. According to the characteristics shown in FIG. 7, in both cases, two catalytic combustible gas treatment devices are installed in the equipment installation area even though two catalytic combustible gas treatment devices are used. The amount of hydrogen treated in the first case installed in is about 70% larger than that in the second case where one catalytic combustible gas treatment device is installed in the equipment installation area. This is because the hydrogen gas from the wet well is released directly to the equipment installation area by the rupture of the rupture disk, so the hydrogen concentration in the equipment installation area is high, and the catalytic combustible installed in the equipment installation area rather than the operation floor area. The hydrogen treatment efficiency by the property gas treatment device is increased. From this, the catalytic combustible gas processing apparatus for processing hydrogen, which is a combustible gas, is supplied from a wet well in which a high concentration of hydrogen gas is accumulated in a primary reactor containment vessel. By installing in the equipment installation area that is directly released, the hydrogen treatment efficiency can be increased. In other words, hydrogen treatment efficiency can be improved by installing a catalytic combustible gas treatment device in an equipment installation area where a high hydrogen concentration is maintained after the rupturable plate is ruptured. As a result, it is possible to reduce the number of installed flammable gas treatment devices.

  The influence of the volume of the equipment installation area on the hydrogen treatment efficiency of the catalytic combustible gas treatment device will be described with reference to FIG. In FIG. 8, the volume of the space formed in the equipment installation area (the volume obtained by removing the volume of the equipment and piping arranged in the equipment installation area from the total volume of the equipment installation area) is standardized by the volume of the wet well. In two cases, 113% case (hereinafter referred to as Case A) and 13% case (hereinafter referred to as Case B), two catalytic combustible gas treatment devices were installed in the equipment installation area. The processing amount of each hydrogen gas in the state is shown. The amount of hydrogen gas treated is normalized by the weight of hydrogen gas present in the wet well before the bursting of the rupturable plate, as in FIG. Based on the characteristics shown in FIG. 8, in the case A where the volume of the space formed in the device installation area is 113% of the volume of the wet well, case B is 13% of the volume of the space. It was found that the amount of hydrogen gas processed was increased by 100% or more as compared with the above case.

  FIG. 9 shows changes with time of the hydrogen concentration in the equipment installation area in each of the two cases shown in FIG. The hydrogen concentration in the device installation area is higher in Case A where the space volume in the device installation area is 113% of the wet well volume than in Case B. This is because, when the volume of the space formed in the equipment installation area is small, the absolute amount of combustible gas released from the wet well to the equipment installation area due to the rupture of the rupture disk is relatively large. This is because it is processed by a small catalytic combustible gas treatment device, and the effect of reducing the hydrogen concentration becomes relatively large, and the hydrogen concentration in the equipment installation area decreases. Since the hydrogen concentration is thus reduced, the processing efficiency of hydrogen gas is reduced when the space volume in the equipment installation area is small. As a result, in order to increase the hydrogen gas processing efficiency of the catalytic combustible gas processing apparatus, it is necessary to increase the effective volume of the space where the combustible gas is first released from the wet well.

  FIG. 10 shows the dependence of the hydrogen gas processing amount on the volume of the space formed in the equipment installation area, which is the space where the combustible gas is first released by the rupture of the rupturable plate from the wet well. As described above, standardized values are used for the equipment installation area and the hydrogen treatment amount in FIG. FIG. 10 shows the characteristics for each case of 15 minutes and 30 minutes from the time of rupture of the rupturable plate. In each case, the amount of hydrogen treatment increases as the volume of the space in the equipment installation area increases. However, when the volume of the space in the equipment installation area, which is standardized by the volume of the wet well, is 75% or more, the degree of increase in the hydrogen treatment amount tends to be saturated. This is because, in a region where the ratio of the volume of the space in the equipment installation area to the volume of the wet well is less than 75%, the hydrogen treated by the catalytic combustible gas treatment device with respect to the volume of the space in the equipment installation area. The amount of gas is not negligible, and the hydrogen concentration in the equipment installation area decreases. However, when the ratio of the volume of the space in the equipment installation area to the wet well volume is 75% or more, the hydrogen treatment amount is the hydrogen in the space. This is because the influence on the concentration is reduced. For this reason, the volume of the space in the equipment installation area, which is the space where the flammable gas is first released from the wet well at the time of the rupture of the rupture disk, is set to 75% or more of the volume of the wet well. The hydrogen concentration in the space in the equipment installation area after the time can be increased, and the hydrogen treatment efficiency by the catalytic combustible gas treatment apparatus installed in the equipment installation area can be improved. As a result, the number of catalytic combustible gas treatment devices installed in the secondary reactor containment vessel can be reduced.

  In addition, when the ratio of the volume of the space in the equipment installation area to the volume of the wet well exceeds 120%, the amount of hydrogen processing in the equipment installation area decreases. For this reason, the ratio of the volume of the space in the equipment installation area to the volume of the wet well is desirably 120% or less. In this case, it can be seen that the hydrogen concentration in the space after opening the rupturable plate can be increased, and the installed processing capacity of the catalytic processor (reactor) can be maintained at 95% or more of the maximum capacity. As a result, the treatment amount can be maintained larger than when the space volume is too small or too large, and the number of catalytic reactors that are combustible gas treatment systems can be reduced.

  An embodiment of the present invention will be described below in consideration of the examination results described above.

  A reactor containment facility used in a nuclear power plant, which is a preferred embodiment of the present invention, will be described with reference to FIG. The reactor containment facility 1 of the present embodiment includes a primary reactor containment vessel 3, a secondary reactor containment vessel 15, and a plurality of catalytic combustible gas treatment devices 27. The primary reactor containment vessel 3 includes an upper lid 4 and is installed on a concrete mat 34. The primary reactor containment vessel 3 is disposed in a steel secondary reactor containment vessel 15 installed on a concrete mat 34. The secondary nuclear reactor containment vessel 15 is arranged in an external vessel 33 made of reinforced concrete installed on a concrete mat 34.

  The pedestal 11 is disposed in the primary reactor containment vessel 3 and installed on the concrete mat 34. A reactor pressure vessel 2 is installed on the pedestal 11. A cylindrical gamma ray shield 5 surrounds the reactor pressure vessel 2 and is installed on the pedestal 11. The outer peripheral part of the annular diaphragm floor 10 is installed on the inner surface of the primary reactor containment vessel 3, and the inner peripheral part of the diaphragm floor 10 is installed on the pedestal 11.

  The dry well 6 and the first pressure suppression chamber 7 are isolated by the diaphragm floor 10. The dry well 6 is disposed above the diaphragm floor 10, and an annular first pressure suppression chamber 7 is disposed below the diaphragm floor 10 and surrounds the pedestal 11. A reactor pressure vessel 2 is disposed in the dry well 6. An inner pressure suppression pool (first pressure suppression pool) 8 filled with cooling water, and an inner wet well (first space region) 9 which is a space above the coolant level of the inner pressure suppression pool 8 are the first. It is formed in the pressure suppression chamber 7. A plurality of vent passages 12 are formed in the pedestal 11 and are arranged at predetermined intervals in the circumferential direction of the pedestal 11. The upper end of each vent passage 12 is opened to the dry well 6, and the lower end portion of each vent passage 12 is opened to the cooling water of the inner pressure suppression pool 8.

  A main steam pipe 37 and a water supply pipe 38 are connected to the reactor pressure vessel 2. The main steam pipe 37 passes through the primary reactor containment vessel 3, the secondary reactor containment vessel 15 and the external vessel 33 and is connected to a turbine (not shown). The feed water pipe 38 passes through the primary reactor containment vessel 3, the secondary reactor containment vessel 15 and the external vessel 33 and is connected to a condenser (not shown) that condenses steam exhausted from the turbine. .

  The primary reactor containment vessel 3 is a reinforced concrete containment vessel (RCCV) used in ABWR, and is provided on a cylindrical portion installed on a concrete mat 34 and an upper end portion of the cylindrical portion to form a ceiling portion. To have a top slab. The upper lid 4 is detachably installed on the top slab.

  The reactor well 22, the fuel storage pool 23, and the equipment temporary storage pool 24 are provided in the primary reactor containment vessel 3 and are arranged above the primary reactor containment vessel 3. The reactor well 22 is disposed directly above the reactor pressure vessel 3, and the fuel storage pool 23 and the equipment temporary storage pool 24 are disposed on both sides of the reactor well 22.

  An annular partition floor 17 is disposed between the primary reactor containment vessel 3 and the secondary reactor containment vessel 15 below the bottom surface of the fuel storage pool 23. The inner periphery of the partition floor 17 is installed on the outer surface of the primary reactor containment vessel 3, and the outer periphery of the partition floor 17 is installed on the inner surface of the secondary reactor containment vessel 15. An annular second pressure suppression chamber 16 is formed between the primary reactor containment vessel 3 and the secondary reactor containment vessel 15 below the partition floor 17 and surrounds the primary reactor containment vessel 3. In the second pressure suppression chamber 16, an annular outer pressure suppression pool (second pressure suppression pool) 25 filled with cooling water, and an annular ring that exists above the coolant level of the outer pressure suppression pool 25. An outer wet well (second space region) 26 is formed. The inner pressure suppression pool 8 and the outer pressure suppression pool 25 are connected by a plurality of communication holes 13 formed in the cylindrical portion of the primary reactor containment vessel 3. The inner wet well 9 and the outer wet well 26 are connected by a plurality of communication holes 14.

  An equipment installation area 20 is formed between the primary reactor containment vessel 3 and the secondary reactor containment vessel 15 above the partition floor 17 and surrounds the cylindrical portion of the primary reactor containment vessel. The volume of the space formed in the device installation area 20 is 113% of the total volume of the inner wet well 9 and the outer wet well 26 (hereinafter referred to as the wet well volume). The space formed in the equipment installation area 20 is a space in the equipment installation area 20 excluding equipment (for example, the catalytic combustible gas processing device 27) and piping installed in the equipment installation area 20. A space where air exists. An operation floor area 21 is formed in the secondary reactor containment vessel 15 above the reactor well 22, the fuel storage pool 23 and the equipment temporary storage pool 24. An operation floor (not shown) that forms the floor surface of the operation floor area 21 is formed in the secondary reactor containment vessel 15. The upper ends of the reactor well 22, the fuel storage pool 23, and the equipment temporary storage pool 24 are surrounded by the operation floor. The operating floor has a circular cross section. An annular gap 39 is formed between the side surface of the operation floor and the inner surface of the secondary reactor containment vessel 15. In addition, since this annular clearance 39 should just connect the apparatus installation area 20 and the driving | operation floor area 21, you may make it the channel | path which exists in several places in the circumferential direction instead of a ring. The equipment installation area 20 and the operation floor area 21 are connected by an annular gap 39. Since the fuel storage pool 23 and the equipment temporary storage pool 24 protrude outward from the outer surface of the cylindrical portion of the primary reactor containment vessel 3, the diameter of the inner surface of the annular gap 39 is the cylinder of the primary reactor containment vessel 3. It is larger than the diameter of the outer surface of the part.

  A plurality of openings 18 penetrating the annular partition floor 17 are formed in the partition floor 17. A rupturable plate 19 is disposed in the opening 18 and installed on the partition floor 17. The opening 8 is sealed by a rupturable plate 19 in a normal state, and communicates the device installation area 20 and the outer wet well 26 when the rupturable plate 19 is ruptured. The rupturable plate 19 is configured to burst at a pressure of 0.42 MPa.

  A plurality of catalytic combustible gas treatment devices 27 are installed in the equipment installation area 20 as shown in FIG. Each catalytic combustible gas treatment device 27 is separately disposed directly above each opening 18.

  The configuration of the catalytic combustible gas processing device 27 will be described in detail with reference to FIG. The catalytic combustible gas treatment device 27 includes a casing 28 that is a cylindrical body having a rectangular cross section, for example, and a catalyst layer 29 filled with a catalyst that promotes a bonding reaction between hydrogen and oxygen. A gas inlet 30 is formed at the lower end of the casing 28 below the catalyst layer 29, and a gas outlet 31 is formed at the upper end of the casing 28 above the catalyst layer 29. The catalytic combustible gas treatment device 27 is installed on the upper surface of the partition floor 17 by a plurality of (for example, four) support members 32 attached to the lower end of the casing 28. The gas inlet 30 is located immediately above the opening 18. The gas inlet 30 communicates with the space in the equipment installation area 20 through the support members 32. A gas outlet 31 is also connected to the space.

  During operation of the nuclear power plant, the dry well 6 and the inner wet well 9 in the primary reactor containment vessel 3 and the outer wet well 26 in the secondary reactor containment vessel 15 are filled with nitrogen gas which is an inert gas. Has been. The equipment installation area 20 and the operation floor area 21 are in an air atmosphere so that workers can enter and exit even during operation of the nuclear power plant.

  An outer peripheral pool 35 filled with cooling water is formed between the secondary reactor containment vessel 15 and the outer vessel 33 and surrounds the secondary reactor containment vessel 15. The outer peripheral pool 35 surrounds the outer pressure suppression pool 25.

  It is assumed that the main steam pipe 37 is broken in the primary reactor containment vessel 3 during operation of the nuclear power plant. Since the pressure in the reactor pressure vessel 2 decreases, the high-temperature and high-pressure cooling water in the reactor pressure vessel becomes steam and is jetted into the dry well 6 from the broken portion of the main steam pipe 37. At this time, normally, a plurality of fuels included in each fuel assembly loaded into the core is operated by operating a safety high-pressure core water injection system provided in the nuclear power plant and injecting cooling water into the core. The rod is cooled. When the main steam pipe 37 is broken and the high-pressure core water injection system is activated, it is a mere coolant loss accident. However, if the high pressure core water injection system fails to operate for some reason, the above-mentioned severe accident occurs.

  When such a severe accident occurs, the steam ejected from the broken portion of the main steam pipe 37 to the dry well 6 contains a large amount of hydrogen which is a combustible gas. The high-temperature and high-pressure steam containing hydrogen in the dry well 6 is discharged into the cooling water in the inner pressure suppression pool 8 through each vent passage 12. The steam is condensed by the cooling water. The temperature of the cooling water in the inner pressure suppression pool 8 rises by condensing the steam. The cooling water whose temperature in the inner pressure suppression pool 8 has risen flows into the outer pressure suppression pool 25 through the communication hole 13 located in the upper portion, and contacts the steel secondary reactor containment vessel 15. Cooled by cooling water. The cooling water in the outer pressure suppression pool 25 cooled by the cooling water in the outer peripheral pool 35 is returned to the inner pressure suppression pool 8 through the communication hole 13 located at the lower part. Since the cooling water in the inner pressure suppression pool 8 is thus cooled by the cooling water in the outer peripheral pool 35, the steam released from the vent passage 12 can be condensed efficiently. The pressure increase in the dry well 6 is suppressed by the condensation of the vapor. The cooling water in the outer peripheral pool 35 is heated by the cooling water in the outer pressure suppression pool 25 to become steam. The generated steam rises in an annular passage 36 formed between the secondary reactor containment vessel 15 and the outer vessel 33, and the outer vessel is opened from an opening (not shown) formed in the ceiling portion of the outer vessel 33. 33 is discharged to the outside. When the water level of the cooling water in the outer peripheral pool 35 falls below the set water level, the outer peripheral pool 35 is supplied with cooling water.

  Since the hydrogen contained in the vapor is not condensed by the cooling water in the pressure suppression pool 8, the hydrogen reaches the outer wet well 26 through the inner wet well 9 and the communication hole 14. In this manner, the hydrogen guided by each vent passage 12 is accumulated in the inner wet well 9 and the outer wet well 26. Due to the accumulation of hydrogen, the pressure in the inner wet well 9 and the outer wet well 26 increases. When the pressure in the outer wet well 26 rises to 0.42 MPa, the rupturable plate 19 that seals the opening 18 bursts.

  Nitrogen gas and hydrogen gas in the outer wet well 26 and the inner wet well 9 rise in the opening 18 and flow into the casing 28 from the gas inlet 30. This hydrogen gas or the like reaches the catalyst layer 29 in the casing 28. Air containing oxygen present in the equipment installation area 20 is supplied to the catalyst tank 29 from the gas inlet 30. Hydrogen and oxygen flowing into the catalyst tank 29 are combined into water by the action of the catalyst existing in the catalyst tank 29. A gas such as air exhausted from the catalyst tank 29 rises in the casing 28 and is released from the gas outlet 31 to the space of the equipment installation area 20. Since the bonding reaction between hydrogen and oxygen is an exothermic reaction, air is heated in the catalyst tank 29 and the temperature of the air rises. Since the air whose temperature has risen rises in the casing 28, the air in the device installation area 20 easily flows into the casing 28 from the gas inlet 30 due to the chimney effect of the casing 28. For this reason, the bonding reaction of hydrogen and oxygen in the catalyst tank 29 is further promoted.

  Since the hydrogen rising through the opening 18 is combined with oxygen by the plurality of catalytic combustible gas processing devices 27 installed in the equipment installation area 20, the hydrogen can be efficiently processed, as shown in FIG. As in A, the hydrogen concentration in the equipment installation area 20 can be reduced. Since hydrogen is efficiently processed in the equipment installation area 20, an increase in the hydrogen concentration in the operation floor area 21 is suppressed.

  The pressure in the inner wet well 9 and the outer wet well 26 increases due to the influence of hydrogen released to the dry well 6 after the severe accident occurs until the rupturable plate 19 bursts. When this pressure reaches 0.42 MPa, the rupturable plate 19 is ruptured, and the pressure in the inner wet well 9 and the outer wet well 26 is instantaneously released to the equipment installation area 20 through the opening 18. As a result, as shown in FIG. 3, the pressure in the inner wet well 9 and the outer wet well 26 decreases, the pressure in the equipment installation area 20 and the operation floor area 21 increases, and the pressure in each area is about 0.15 MPa. It is settled at.

  In this embodiment, the space of the equipment installation area 20 is set to 113% of the wet well volume, and a plurality of catalytic combustible gas treatment devices 27 are installed in the equipment installation area 20. Thus, the hydrogen released from the outer wet well 26 can be processed efficiently. For this reason, hydrogen released into the primary reactor containment vessel 3 at the time of a severe accident can be processed in a short time. An increase in the hydrogen concentration in each of the equipment installation area 20 and the operation floor area 21 where air is present can be suppressed, and a rapid reaction between hydrogen and oxygen in those areas can be prevented.

  In this embodiment, since the catalytic combustible gas treatment device 27 is disposed directly above the opening 18 where the rupturable plate 19 is installed, the hydrogen concentration passing through the opening 18 when the rupturable plate 19 is ruptured. Since the high gas can be guided to the catalytic combustible gas processing device 27, the hydrogen processing efficiency by the catalytic combustible gas processing device 27 is further improved.

  In this embodiment, the volume of the space in the equipment installation area 20 is 113% of the wet well volume, but the volume of the space in the equipment installation area 20 is arbitrarily included in the range of 75% to 120% of the wet well volume. Even if it is set to the above value, the above-mentioned effects can be obtained.

  Each catalytic combustible gas treatment device 27 may be disposed in the device installation area 20 at a position shifted from directly above the opening 18 in the horizontal direction and may be installed on the partition floor 17. Even in this case, since the plurality of catalytic combustible gas treatment devices 27 are arranged in the equipment installation area 20 having a volume of 113% of the wet well volume, the hydrogen treatment efficiency is improved as in the above-described embodiment. The hydrogen in the primary reactor containment vessel 3 can be processed in a short time. However, since each catalytic combustible gas treatment device 27 is disposed in the equipment installation area 20 at a position shifted from directly above the opening 18 in the horizontal direction, after the rupturable plate 19 has ruptured, the opening 18 The hydrogen released into the equipment installation area 20 is diluted by the air in the equipment installation area 20 rather than the embodiment described above. For this reason, since the gas having a lower hydrogen concentration than that of the above-described embodiment is guided to the catalyst tank 29, the hydrogen treatment efficiency is lower than that of the above-described embodiment.

  In the embodiment shown in FIG. 1, the catalytic combustible gas treatment device 27 that does not provide dynamic equipment is installed in the equipment installation area 20, but dynamic equipment (for example, a blower) is provided in the equipment installation area 20. A supply pipe may be connected, and this supply pipe may be connected to the gas inlet 30 of the catalytic combustible gas processing device 27 installed outside the external container 33. In this configuration, the return pipe connected to the device installation area 20 is connected to the gas outlet 31. The hydrogen released to the equipment installation area 20 due to the rupture of the rupturable plate 19 is led to the catalytic combustible gas treatment device 27 through the supply pipe together with the air in the equipment installation area 20 by the driving of the dynamic equipment. It is processed in the combustible gas processing device 27. The gas having a reduced hydrogen concentration discharged from the catalytic combustible gas processing device 27 is returned to the equipment installation area 20 through the return pipe. Even in such an embodiment, since the hydrogen directly discharged to the equipment installation area 20 is processed by the catalytic combustible gas processing device 27, the hydrogen processing efficiency can be improved as in the embodiment shown in FIG. it can. However, in the embodiment in which the catalytic combustible gas treatment device 27 is disposed outside the external container 33, dynamic equipment is required, and piping is also required. Compared to such an embodiment, the embodiment shown in FIG. 1 in which the catalytic combustible gas treatment device 27 is installed in the equipment installation area 20 does not require dynamic equipment and piping, and the reactor containment facility The configuration of can be simplified.

  The present invention can be applied to a boiling water nuclear power plant.

  DESCRIPTION OF SYMBOLS 1 ... Reactor containment equipment, 2 ... Reactor pressure vessel, 3 ... Primary reactor containment vessel, 6 ... Dry well, 7 ... First pressure suppression chamber, 8 ... Inner pressure suppression pool, 9 ... Inner wet well, 10 ... Diaphragm floor, 11 ... Pedestal, 12 ... Vent passage, 15 ... Secondary reactor containment vessel, 16 ... Second pressure suppression chamber, 17 ... Partition floor, 18 ... Opening, 19 ... Rupture plate, 20 ... Equipment installation area , 21 ... operation floor area, 25 ... outer pressure suppression pool, 26 ... outer wet well, 27 ... catalytic combustible gas treatment device, 28 ... casing, 29 ... catalyst layer, 33 ... outer container, 35 ... outer peripheral pool.

Claims (4)

A primary reactor containment vessel containing a reactor pressure vessel, a secondary reactor containment vessel covering the primary reactor containment vessel, and a plurality of combustible gas treatment devices for treating hydrogen,
The primary reactor containment vessel forms therein a dry well in which the reactor pressure vessel is disposed, and a first pressure suppression chamber isolated from the dry well,
The first pressure suppression chamber has a first pressure suppression pool filled with cooling water, and a first space region formed above the water surface of the cooling water of the first pressure suppression pool;
A partition floor disposed between the primary reactor containment vessel and the secondary reactor containment vessel is installed in the primary reactor containment vessel and the secondary reactor containment vessel;
A second pressure suppression pool that is communicated with the first pressure suppression pool and is filled with cooling water, and a second pressure suppression pool that is formed above the cooling water surface of the other pool and communicated with the first space region. A second pressure suppression chamber having a space region is formed between the primary reactor containment vessel and the secondary reactor containment vessel below the partition floor;
An equipment installation area is formed between the primary reactor containment vessel and the secondary reactor containment vessel above the partition floor,
An operation floor area communicated with the equipment installation area is formed between the primary reactor containment vessel and the secondary reactor containment vessel above the equipment installation area,
When the rupture disc is ruptured by being blocked by a rupture disc, a plurality of openings that connect the second space region and the device installation area are formed in the partition floor,
The plurality of combustible gas treatment devices are communicated to the equipment installation area;
The volume of the space in the equipment installation area is in the range of 75% to 120% of the total volume of the volume of the first space area and the volume of the second space area. .   The nuclear reactor containment facility according to claim 1, wherein the combustible gas treatment device is disposed immediately above the opening.   The reactor containment facility according to claim 1 or 2, wherein the combustible gas treatment device is disposed in the equipment installation area and has a catalyst layer therein.   4. The outer peripheral pool having an outer vessel covering the secondary reactor containment vessel and filled with cooling water is formed between the secondary reactor containment vessel and the outer vessel. 5. Reactor containment equipment according to item 1.

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