JPH07104087A - Vent device for reactor container - Google Patents

Abstract

PURPOSE:To reduce the dose equivalent of members of the public by rare gas. CONSTITUTION:A dry well vent line 10 and a wet well vent line 11 provided with valves 8, 9 respectively as pressure discharge systems are installed on a dry wall 4 and a wet well 7 formed in a reactor container 3. A dry filter 12 and a stack 13 are connected on the discharge side of the vent lines 10, 11. A heating mechanism is provided on the dry filter 12, the heating mechanism is connected to a power source 17, and the power source 17 is connected to a control device 16. When a signal is sent to the control device 16 by the judgment of in operator, the power source 17 is started, and the heating mechanism is operated to pre-heat the dry filter 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vent device for a reactor containment vessel of a nuclear power plant and reduces the dose equivalent of noble gas discharged by pressure release in the reactor containment vessel due to a severe accident or the like. The present invention relates to a reactor containment vessel venting device for separating radioactive substances in gas.

[0002]

2. Description of the Related Art Conventionally, as a pressure release system of a reactor containment vessel, as shown in the schematic configuration diagram of a pressure release system of a boiling water reactor of FIG. In the reactor containment vessel 3 in which is installed the dry well 4 is formed in the upper part of the reactor pressure vessel 2, the pressure suppression chamber 5 is provided in the lower part, and the cooling water pool 6 and the wet well 7 are formed.

A dry well vent line 10 and a wet well vent line 11 having valves 8 and 9 as pressure release systems are installed in the dry well 4 and the wet well 7, respectively. The internal pressure can be released to the outside from the exhaust tower 13 via the filter 12.

In addition, if a coolant loss accident from a coolant pipe or the like (not shown) occurs in the boiling water nuclear power plant from the cooling water pool 6, cooling water is injected into the reactor pressure vessel 2. Then, the core 1 is cooled and the emergency core cooling system 14 for maintaining the soundness of the core 1 and the pressure inside the reactor containment vessel 3 rises due to the steam leak from the steam pipes, etc. A reactor containment vessel cooling system 15 for spraying cooling water into the dry well 4 to condense steam is provided in order to prevent the integrity of the vessel 3 from being damaged, such as damage to the vessel 3.

Even if the reactor containment vessel cooling system 15 does not operate and the pressure in the reactor containment vessel 3 rises, the wet well 7 to the valve 9 of the wet well vent line 11 should be used.
The internal pressure can be released and the soundness of the reactor containment vessel 3 can be maintained. Further, when the wet well 7 is full of water, the valve 8 of the dry well vent line 10 is opened to release the pressure from the dry well 4 to maintain the soundness of the reactor containment vessel 3.

[0006]

Even if a large-scale accident such as a loss of coolant occurs, the reactor is cooled by the operation of the emergency core cooling system 14 and the reactor containment vessel cooling system 15, and an accident occurs. Are converged. In the unlikely event that this emergency core cooling system 14
And dry well vent line 10 and wet well vent line 11 even if the reactor containment cooling system 15 does not operate.
As a result, the soundness of the reactor containment vessel 3 is finally maintained.

Further, when the pressure in the reactor containment vessel 3 is released, radioactive substances existing in the reactor containment vessel 3 are guided to the filter 12 through the dry well vent line 10 or the wet well vent line 11 and removed. The amount of radioactive substances emitted into the atmosphere can be reduced.

However, inactive gas such as radioactive noble gas cannot be removed by the filter 12, and when the pressure is increased and discharged so that the radioactive noble gas is not sufficiently attenuated in the reactor containment vessel 3, There is a problem that the dose equivalent of the public due to radioactive noble gas increases.

The present invention has been made to solve the above problems, and a vent device for a reactor containment vessel which reduces the dose equivalent to the public due to the rare gas discharged due to the pressure release in the reactor containment vessel. To provide.

Further, according to the present invention, when pressure is released inside the reactor containment vessel, radioactive noble gas or the like is released into the atmosphere even if the time decay of the radioactive material inside the reactor containment vessel is not sufficient. It is intended to provide a vent device for a reactor containment vessel that reduces the radiation dose equivalent to the public due to the radioactive substances released into the atmosphere.

[0011]

SUMMARY OF THE INVENTION A first aspect of the present invention is a reactor containment vessel which houses a reactor pressure vessel having a built-in reactor core and is provided with a pressure suppression chamber, the pressure for reducing the pressure in the containment vessel. It comprises a discharge system, a dry filter for removing radioactive substances contained in the gas discharged by the pressure discharge system, and a device for heating the dry filter.

A second aspect of the present invention is a reactor containment vessel that houses a reactor pressure vessel having a built-in core and is provided with a pressure suppression chamber, and a pressure release system for reducing the pressure in the containment vessel; It comprises a dry filter for removing radioactive substances contained in the gas released by the release system and an apparatus capable of supplying oxygen to the dry filter downstream side pipe.

A third aspect of the present invention is a reactor containment vessel which houses a reactor pressure vessel having a built-in reactor core and is provided with a pressure suppression chamber, and a pressure release system for reducing the pressure of the containment vessel, and the pressure release system. It consists of a cooling device for cooling the gas discharged from the system. According to a fourth aspect of the present invention, in a reactor containment vessel that houses a reactor pressure vessel having a built-in reactor core and is provided with a pressure suppression chamber, a pressure release system for lowering the pressure in the containment vessel and a pressure release system A storage container that temporarily stores the released gas, a filter that reduces the radioactive substance in the gas that is released from the storage container, a separation device that separates the radioactive substance in the gas that has passed through this filter, and The radioactive substance separated by the separator is composed of the reactor containment vessel and a circulation system for circulating the radioactive material to the storage vessel.

A fifth aspect of the invention is characterized in that in the fourth aspect, a radioactive substance holding device is used instead of the circulation system for circulating the radioactive substance to the containment vessel and the storage vessel.

[0015]

In the first aspect of the invention, when the containment vessel is vented, the dry filter is heated so that water vapor contained in the vent gas is not removed by the dry filter.
By including water vapor in the exhaust gas, energy due to the latent heat of the water vapor is given to the exhaust gas to generate buoyancy,
Increase the elevation of exhaust gas to reduce the dose equivalent of noble gas.

In the second aspect of the invention, hydrogen contained in the exhaust gas flowing through the exhaust stack at the time of venting the containment vessel,
Utilizing the heat energy obtained by mixing with oxygen injected from an external oxygen supply device and forcibly combusting it, the rising altitude of the exhaust gas is increased and the dose equivalent of the public due to the rare gas is reduced.

In the third aspect of the present invention, at the time of venting the containment vessel, the flow rate of the exhaust gas is reduced by discharging it through a large diameter pipe, and the exhaust gas is converted into liquid nitrogen by a cooling device installed on the downstream side. By cooling and liquefying the high-temperature released gas to below the boiling point and recovering it from the drain pipe, the release of radioactive substances into the environment at the time of an accident is suppressed.

According to the fourth aspect of the present invention, when the reactor containment vessel is vented, it is a separator installed downstream of the filter for reducing radioactive substances in the exhaust gas, and it is heavier than a stable substance in the exhaust gas that has passed through the filter. By separating and circulating radioactive substances, the radioactive substances in the exhaust gas released into the atmosphere can be reduced and released into the atmosphere even if the time decay in the reactor containment vessel before venting cannot be expected. Reduce the dose equivalent to the public due to radioactive materials released.

In the fifth aspect of the invention, when venting the reactor containment vessel, a centrifugal separator installed downstream of the filter for reducing radioactive substances in the exhaust gas is used, compared to stable substances in the exhaust gas passing through the filter. By centrifuging heavy radioactive substances and holding them with a radioactive substance holding device, even if the time decay in the reactor containment vessel before venting cannot be expected, radioactive substances in the exhaust gas released into the atmosphere To reduce the dose equivalent to the public due to radioactive materials discharged into the atmosphere.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a vent device for a reactor containment vessel according to the present invention will be described with reference to FIGS. Figure 1
1 is a schematic configuration diagram of a pressure release system of a boiling water reactor, in which a reactor containment vessel 3 in which a reactor pressure vessel 2 containing a core 1 is installed is a dry well 4 above the reactor pressure vessel 2.
Of the cooling water pool 6
And a wet well 7 are formed.

The dry well 4 and the wet well 7 are provided with a dry well vent line 10 and a wet well vent line 11 with valves 8 and 9 interposed, respectively. It can be discharged to the outside from the exhaust tower 13 through the dry filter 12.

The dry filter 12 is equipped with a heating mechanism such as a heater. Before the containment vessel is vented, a signal 18 is sent to the control device 16 at the operator's discretion to activate the power supply 17 to preheat the dry filter 12 by a heating mechanism such as a heater. When the containment vessel is vented, the exhaust gas passes through the dry filter 12 preheated by a heater or the like and is discharged from the exhaust tower 13.

Next, the operation of the above configuration will be described. Even if a large-scale accident such as a loss of coolant occurs, the protective devices for the emergency core cooling system 14 and the reactor containment vessel cooling system 15 operate to keep the reactor healthy. Even if the emergency core cooling system 14 or the reactor containment vessel cooling system 15 does not operate and the pressure in the reactor containment vessel 3 rises, the wet well vent line 11 or the dry well vent line 10 is used to Therefore, the soundness of the reactor containment vessel 3 is maintained.

Since the pressure release from the reactor containment vessel 3 is performed through the dry filter 12, the emission amount of the particulate nuclides into the atmosphere is reduced, but the inert gas such as the rare gas is reduced to the dry filter. Cannot be removed by 12.

However, the dry filter 12 is preheated by a heater or the like before the containment vessel vent is started, and the water vapor in the exhaust gas passes through the dry filter 12 without being condensed. Therefore, the exhaust gas discharged from the exhaust tower 13 contains water vapor, and the latent heat of the water vapor gives thermal energy to the exhaust gas to promote the rise of the exhaust gas,
Increase the distance between the noble gas emitted as a radiation source and the public to reduce the exposure of the public.

Next, an example of the effect of the above operation will be described. FIG. 2 shows the relationship between the water vapor ratio (mass ratio) in the exhaust gas and the exhaust gas rising altitude. Figure 3 shows the decay time and release point of noble gas in the reactor containment vessel.
The relationship of the dose equivalent to the whole body at a point of 0.75 km is compared between the conventional vent equipment having a wet filter and the case of using this embodiment.

In the conventional example, the wet filter removes water vapor from the exhaust gas, and the exhaust gas temperature is also lowered. On the other hand, in the embodiment of the present invention, the amount of water vapor in the exhaust gas is maintained,
Exhaust gas humidity is also maintained at the temperature inside the PCV.

Therefore, by using the present embodiment, the rise of exhaust gas is promoted, and even if the rare gas decay time in the reactor containment vessel cannot be sufficiently secured, the dose equivalent of the rare gas is kept low. To be

FIG. 4 shows the relationship between the distance from the discharge point and the dose equivalent to the whole body when the decay time of the rare gas in the reactor containment vessel is 5 hours, when the conventional example and this example are used. It is compared with. In the conventional example, the dose equivalent is relatively high in the vicinity of the emission point, but by using this embodiment, the dose equivalent in the vicinity of the emission point can be significantly reduced.

2 to 4, the pressure rise from the wet well vent line 11 is assumed, and the rising height of the exhaust gas is calculated by the Briggs equation. In addition, the dose equivalent was evaluated using the linear Gaussian plume model, and the meteorological conditions were such that the rise in exhaust gas was relatively suppressed. Atmospheric safety level F and wind speed 5m / s.

Next, a second embodiment of the vent device for the reactor containment vessel according to the present invention will be described with reference to FIGS. 5 and 6. In FIG. 5, a reactor containment vessel 3 in which a reactor pressure vessel 2 containing a core 1 is installed has a dry well 4 formed in an upper portion of the reactor pressure vessel 2 and a pressure suppression chamber 5 provided in a lower portion thereof. To form a cooling water pool and a wet well 7. The dry well 4 and the wet well 7 are provided with a dry well vent line 10 and a wet well vent line 11 with valves 8 and 9 interposed, respectively, and exhaust through a pressure filter 12 in the reactor pressure vessel 3 respectively. It can be discharged from the tower 13 to the outside.

An exhaust gas flow meter 25, a hydrogen concentration measuring device 24 and an oxygen concentration measuring device 23 are installed inside the exhaust stack 13 as a measuring system 20. Further, in order to burn hydrogen in the exhaust stack 13, an oxygen supply device 30 is installed outside and an injection valve is installed.
Oxygen is injected into the stack via 27 and 26.

In order to prevent excess hydrogen and oxygen from being combined in the exhaust pipe 13, a nitrogen supply device 31 is installed outside, and nitrogen is injected into the exhaust pipe 13 via the injection valves 29 and 28.

The concentrations of hydrogen and oxygen in the exhaust stack 13 are measured by an exhaust gas flow meter 25, a water concentration measuring device 24 and an oxygen concentration measuring device.
Based on the signal of 23, the stack gas concentration control device 22 determines the oxygen injection amount and the nitrogen injection amount by the injection valves 26, 27, 28, 29.
Is adjusted and controlled to be a constant value.

Even if a large-scale accident such as a loss of coolant occurs, the protective device for the emergency core cooling system 14 and the reactor containment vessel cooling system 15 operates to keep the reactor sound. By any chance
This emergency core cooling system 14 or reactor containment cooling system
Even if 15 does not operate and the pressure in the containment vessel 3 rises,
Releasing the wet well vent line 11 or the dry well vent line 10 finally depressurizes the reactor containment vessel 3 and maintains its soundness.

The reactor containment vessel 3 or the pressure relief filter 12
Since it is carried out through the filter, the emission amount of the particle nuclide into the atmosphere is reduced, but the inert gas such as the rare gas is removed by the filter 12
Therefore, it may give external exposure to the public due to radioactive noble gas because it cannot be removed by.

In such a case, however, combustible hydrogen is contained in the exhaust gas, and oxygen and nitrogen controlled by the stack gas concentration control device 22 are injected into the exhaust stack 3, whereby Combustion can occur within the stack to provide thermal energy to the exhaust gas. The addition of this heat energy promotes the rise of exhaust gas and increases the distance between the radioactive noble gas that is a radiation source and the public.

Next, an example of the effect of the above operation will be described. FIG. 6 compares the relationship between the start time of the reactor containment vessel venting and the dose equivalent to the whole body at a typical site boundary between the conventional example and the case of using this example. By using this embodiment, even if the rare gas decay time in the containment vessel cannot be sufficiently secured, the dose equivalent of the rare gas can be kept low.

Next, a third embodiment of the vent device for the reactor containment vessel according to the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a schematic configuration diagram of a pressure release system of a boiling water reactor, in which a reactor containment vessel 3 in which a reactor pressure vessel 2 containing a core 1 is installed is located above the reactor pressure vessel 2. The dry well 4 is formed, the pressure suppression chamber 5 is provided in the lower part, and the cooling water pool 6 and the wet well 7 are formed.

Dry well vent lines equipped with valves 8 and 9 for the dry well 4 and the wet well 7, respectively.
10 and a wet well vent line 11 are installed so that the pressure in the reactor pressure vessel 3 can be discharged to the outside from the building bend stack 32 through the filter 12.

Here, a cooling device 33, which is a U-shaped heat exchanger through which liquid nitrogen can circulate, is arranged on the downstream side of the filter 12, and the valve 8 or the valve 9 is opened. A signal is sent to the control device 34, and the pump 35 is started to supply liquid nitrogen from the liquid nitrogen tank 36 to the cooling device 33 to cool the exhaust gas.

The cooled exhaust gas is transferred to the airtight drain recovery tank 38 via the drain pipe 37. The liquid nitrogen is vaporized by the energy from the exhaust gas and sent to the nitrogen recovery tank 39.

The piping from the downstream side of the filter 12 to the building vent stack 32 is a large diameter piping 40 in order to reduce the exhaust gas flow velocity and improve the cooling performance.

Next, the operation of the above configuration will be described. If a large-scale accident such as loss of coolant occurs,
The protective devices for the emergency core cooling system 14 and the reactor containment cooling system 15 operate to keep the reactor healthy. Even if the emergency core cooling system 14 or the reactor containment vessel cooling system 15 does not operate and the pressure in the reactor containment vessel 3 rises, the wet well vent line 11 or the dry well vent line 10
Finally, the reactor containment vessel 3 is depressurized and its soundness is maintained.

Since the pressure release from the reactor containment vessel 3 is performed through the filter 12, the release amount of the particulate nuclides into the atmosphere is reduced, but the inert gas such as rare gas is reduced by the filter 12. Since it cannot be removed, it may give the public external exposure to radioactive noble gases.

In such a case, krypton and sequinone can be considered as the rare gases which affect the external exposure of the exhaust gas. The boiling points of these elements are approximately -153 each.
℃ and about -108 ℃, which is higher than the boiling point of liquid nitrogen, -196 ℃.

Therefore, by providing the cooling device 33 on the downstream side of the filter 12, these exhaust gases can be liquefied and transferred to the airtight drain recovery tank 38 via the drain pipe 37. This makes it possible to suppress the amount of radioactive substances released into the atmosphere.

FIG. 8 compares the relationship between the start time of the reactor containment vessel vent and the dose and equivalent to the whole body at a typical site boundary, compared with the case of using the conventional example and this example. Here, it is assumed that the rare gas liquefaction efficiency according to the present embodiment is 80%. In addition, in the plant equipped with this embodiment, it is assumed that the rare gas is discharged from the ground at the time of the accident.

By using this embodiment, even if the rare gas decay time in the containment vessel cannot be sufficiently secured, the dose equivalent of the rare gas can be kept low.

FIG. 9 is a schematic block diagram of the pressure release system of the fourth embodiment according to the present invention. The difference from the first embodiment shown in FIG. 1 is that the dry well 4 and the wet well 7 are provided with pressure detectors 19 respectively, and a signal 18 from the pressure detector 19 can automatically perform residual heat of the dry filter 12. It is the one.

Next, a fifth embodiment of the vent device for the reactor containment vessel according to the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 is a schematic configuration diagram of a pressure release system of a boiling water reactor, in which a reactor containment vessel 3 in which a reactor pressure vessel 2 containing a core 1 is installed is located above the reactor pressure vessel 2. The dry well 4 is formed, the pressure suppression chamber 5 is provided in the lower part, and the cooling water pool 6 and the wet well 7 are formed.

The dry well 4 and the wet well 7
A dry well vent line 10 and a wet well vent line 11 with valves 8 and 9 respectively inserted therein are installed as pressure release systems, and the pressure in the reactor containment vessel 3 is temporarily released to the storage vessel 41. It is supposed to be done. The gas discharged into the storage container 41 passes through the filter 12, flows into the centrifugal separator 42, is separated into radioactive substances by the centrifugal separator 42, and is discharged from the exhaust pipe 13 to the outside. .

The radioactive substance separated by the centrifugal separator 17 passes through the radioactive gas circulation system 43 and is circulated in the reactor containment vessel 3 and the storage vessel 41. Primary containment vessel 3
The storage container 41 and the storage container 41 are connected by a communication pipe 44.

Next, the operation of the above configuration will be described. If a large-scale accident such as loss of coolant occurs, the emergency core cooling system 14 or the reactor containment cooling system 15
Protector is activated to keep the reactor healthy. Even if the emergency core cooling system 14 and the reactor containment vessel cooling system 15 do not operate and the pressure in the reactor containment vessel 3 rises, the wet well vent line 11 or the dry well vent line 10
Finally, the reactor containment vessel 3 is depressurized and the soundness is maintained.

The pressure from the reactor containment vessel 3 is once released to the storage vessel 41 to reduce the pressure change and impact. Since the gas discharged into the storage container 16 passes through the filter 12, the amount of particulate nuclide discharged into the atmosphere is reduced.

The inert gas such as the radioactive noble gas which cannot be removed by the filter 12 is heavier than the stable gas in the exhaust gas and is centrifuged by the centrifugal separator 42 so that only the light stable gas is exhausted from the exhaust pipe 13 To the outside. The radioactive substance centrifuged by the centrifuge 42 is the radioactive gas circulation system 43.
Then, it is circulated through the communication pipe 44 to the reactor containment vessel 3 and the storage vessel 41.

Next, an example of the effect of the above operation will be described. FIG. 11 is a characteristic diagram showing the relationship between the distance from the exhaust stack 13 and the dose equivalent for the whole body in comparison between the conventional example and the example of the present invention. By using the embodiment of the present invention, the dose equivalent to the whole body of the public can be reduced as compared with the conventional example.

In FIG. 11, the separation coefficient of the partial pressure of gas in the centrifugal force field was evaluated in accordance with Bo-ltzmann's law in the countercurrent centrifugal separator. The circumferential speed of the centrifuge is 4
The separation gas was 00 m / sec, and the separation gas was Kr-85 m and CO ₂ .

Next, a sixth embodiment of the vent device for the reactor containment vessel according to the present invention will be described with reference to FIGS. FIG. 12 is a schematic configuration diagram of a pressure release system of a boiling water reactor, in which a reactor containment vessel 3 in which a reactor pressure vessel 2 containing a core 1 is installed is located above the reactor pressure vessel 2. The dry well 4 is formed and provided in the pressure suppression chamber 5 at the lower part to form the cooling water pool 6 and the wet well 7.

The dry well 4 and the wet well 7 are provided with a dry well vent line 10 and a wet well vent line 11 with pressure release systems 8 and 9, respectively, and are installed in the reactor containment vessel 3. The pressure is temporarily released to the storage container 41.

The gas discharged to the storage container 41 is filtered by the filter 12
The radioactive substance is separated by the centrifuge 42 via the, and is discharged from the exhaust pipe 13 to the outside. The radioactive substance separated by the centrifuge 42 flows through the inflow pipe 46, flows into and is held in the radioactive gas holding device 45, and then flows through the outflow pipe 47 and is discharged from the exhaust pipe 13.

Next, the operation of the above configuration will be described. Even if a large-scale accident such as a loss of coolant occurs, the protective devices for the emergency core cooling system 14 and the reactor containment vessel cooling system 15 operate to keep the reactor healthy. Even if the emergency core cooling system 14 and the reactor containment vessel cooling system 15 do not operate and the pressure in the reactor containment vessel 3 rises, the wet well vent line 11 or the dry well vent line 10 is released. Finally, the reactor containment vessel 3 is depressurized to maintain its soundness.

The pressure from the reactor containment vessel 3 is once released to the storage vessel 41 to mitigate the pressure change and impact. Since the gas discharged into the storage container 41 passes through the filter 12,
Filters 12 reduce emissions of particulate nuclides into the atmosphere
The inert gas such as a radioactive noble gas that cannot be removed by the method is heavier than the stable gas in the exhaust gas, is centrifuged by the centrifuge 42, and releases only the light stable gas from the exhaust pipe 13 to the outside. . The radioactive substance centrifuged by the centrifuge 42 is attenuated by the radioactive gas holding device 45, and then discharged from the exhaust pipe 13.

Next, an example of the effect of the above operation will be described. FIG. 13 compares the relationship between the distance from the exhaust stack 13 and the dose equivalent for the whole body between the case of using the conventional example and the case of using this example. By using this embodiment, the dose equivalent to the whole body of the public can be reduced as compared with the conventional example.

In FIG. 13, in the countercurrent centrifuge 42, the partial pressure of the gas in the centrifugal force field is changed to the Boltsman (Boltman).
The separation factor was evaluated according to Zmann's law. centrifuge
The circumferential velocity of 42 was 400 m / sec, and the separation gas was Kr-85 m and CO ₂ . The Kr-85m holding time of the radioactive gas holding device 45 was set to 24 hours.

FIG. 14 shows a seventh embodiment of the present invention, and FIG. 15 shows an eighth embodiment of the present invention. That is, in the seventh embodiment, the dry filter 12 is connected to the downstream side of the storage container 41, and the centrifugal separator 42 is connected in multiple stages to the downstream side of the dry filter 12 to enhance the centrifugal separation capacity. It is a thing. The radioactive gas separated by these centrifuges 42 passes through the radioactive gas circulation system 43 and is circulated in the reactor containment vessel 3 and the storage vessel 41. Since the operation and effect of this seventh embodiment is similar to that of the fifth embodiment, its explanation is omitted.

In the eighth embodiment, the centrifugal separator 42 in the sixth embodiment is multi-staged to enhance the centrifugal separation capacity. That is, the gas discharged into the storage container 41 is separated into radioactive substances by the multistage centrifugal separator 42 through the filter 12, and is discharged from the exhaust pipe 13 to the outside. The radioactive substance separated by the centrifuge 42 is held by the radioactive gas holding device 45 and then discharged from the exhaust pipe 13.

In each of the above-mentioned embodiments, the example of the separating device using the centrifuge 42 has been described. However, a laser separating device for guiding the gas ionized only by the laser to the electric field and separating it by utilizing the Coulomb force is used. Can be used.

[0069]

According to the first aspect of the present invention, when the pressure in the reactor containment vessel is abnormally increased due to a severe accident or the like, the buoyancy of the exhaust gas accompanying the release of the increased pressure is increased to increase the radiation source. It is possible to increase the distance between the radioactive noble gas and the target of exposure, and to reduce the dose equivalent of the public due to the radioactive noble gas.

According to the second aspect of the invention, when the pressure in the reactor containment vessel is abnormally increased due to a severe accident or the like, hydrogen in the exhaust gas discharged along with the release of the increased pressure is injected from the external tank. By increasing the buoyancy of the exhaust gas obtained by forcibly mixing and burning the oxygen
It is possible to reduce the dose equivalent of radioactive noble gas to the surrounding public.

According to the third aspect of the present invention, when the pressure inside the reactor containment vessel is abnormally increased due to a severe accident or the like, the exhaust gas accompanying the release of the increased pressure is cooled to expose the surrounding public. It is possible to significantly reduce the safety of the plant by suppressing the release of radioactive noble gas that may pose the risk of. Further, by improving the plant safety, it is possible to reduce the height of the exhaust stack, which was 100 m or more above the ground.

According to the fourth and fifth aspects of the invention, when the pressure in the reactor containment vessel is abnormally increased due to a severe accident or the like,
Even if the time decay in the reactor containment vessel cannot be expected, the radioactive substances in the exhaust gas due to the release of this increased pressure are removed by a filter, and the inert gas such as radioactive noble gas that cannot be removed by the filter is centrifuged. By separating, it is possible to reduce the amount of radioactive material released into the atmosphere and reduce the dose equivalent of the radioactive material to the public.

[Brief description of drawings]

FIG. 1 is a system diagram showing a first embodiment of a vent device for a containment vessel according to the present invention.

FIG. 2 is a characteristic diagram showing a relationship between a rate of water vapor in exhaust gas and an exhaust gas rising height.

FIG. 3 is a curve diagram showing the relationship between the noble gas decay time in the reactor containment vessel and the dose equivalent for the whole body in comparison between the first embodiment of the present invention and the conventional example.

FIG. 4 is a curve diagram showing the relationship between the distance from the release point and the dose equivalent for the whole body in comparison between the first embodiment of the present invention and the conventional example.

FIG. 5 is a system diagram showing a second embodiment of a vent device for a reactor containment vessel according to the present invention.

FIG. 6 is a curve diagram showing the relationship between the time until the venting of the reactor containment vessel and the whole body exposure dose in comparison between the second embodiment of the present invention and the conventional example.

FIG. 7 is a system diagram showing a third embodiment of a vent device for a reactor containment vessel according to the present invention.

FIG. 8 is a curve diagram showing the relationship between the noble gas decay time in the reactor containment vessel and the dose to the whole body in comparison between the third embodiment of the present invention and the conventional example.

FIG. 9 is a system diagram showing a fourth embodiment of a vent device for a reactor containment vessel according to the present invention.

FIG. 10 is a system diagram showing a fifth embodiment of a vent device for a reactor containment vessel according to the present invention.

FIG. 11 is a curve diagram showing the relationship between the distance from the exhaust stack and the dose equivalent for the whole body in comparison between the fifth example of the present invention and the conventional example.

FIG. 12 is a system diagram showing a sixth embodiment of a vent device for a reactor containment vessel according to the present invention.

FIG. 13 is a curve diagram showing the relationship between the distance from the exhaust stack and the dose equivalent for the whole body in comparison between the sixth embodiment of the present invention and the conventional example.

FIG. 14 is a system diagram showing a seventh embodiment of the vent device for the reactor containment vessel according to the present invention.

FIG. 15 is a system diagram showing an eighth embodiment of the vent device for the reactor containment vessel according to the present invention.

FIG. 16 is a system diagram showing a conventional vent device for a reactor containment vessel.

[Explanation of symbols]

1 ... Reactor core, 2 ... Reactor pressure vessel, 3 ... Reactor containment vessel,
4 ... dry well, 5 ... pressure suppression chamber, 6 ... cooling pool,
7 ... Wet well, 8, 9 ... Valve, 10 ... Dry well vent line, 11 ... Wet well vent line, 12 ... Dry filter, 13 ... Exhaust stack, 14 ... Emergency core cooling system, 15 ... Reactor containment vessel cooling System, 16 ... Control device, 17 ... Power supply, 18 ... Signal, 19 ... Pressure detector, 20 ... Measuring system, 21 ... DC power supply, 22 ...
Stack gas concentration control device, 23 ... Oxygen concentration measurement device, 24
… Hydrogen concentration measuring device, 25… Exhaust gas flow meter, 26, 27, 28,
29 ... Injection valve, 30 ... Oxygen supply device, 31 ... Nitrogen supply device, 32
… Building vent stack, 33… Cooling device, 34… Control device,
35 ... Pump, 36 ... Liquid nitrogen tank, 37 ... Drain pipe, 38 ...
Drain recovery tank, 39 ... Nitrogen recovery tank, 40 ... Large diameter pipe, 41 ... Storage container, 42 ... Centrifuge, 43 ... Radioactive gas circulation system, 44 ... Communication pipe, 45 ... Radioactive gas holding device, 46 ... Inflow pipe , 47 ... Outflow pipe.

Front page continuation (72) Inventor Seijiro Suzuki 8 Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa Stock company Toshiba Yokohama office

Claims (5)

[Claims] 1. A reactor containment vessel for accommodating a reactor pressure vessel having a built-in core and having a pressure suppression chamber,
A vent device for a reactor containment vessel, comprising a pressure release system for reducing the pressure in the reactor containment vessel and a dry filter having a heating mechanism connected to the pressure release system. 2. A reactor containment vessel for accommodating a reactor pressure vessel having a built-in core and having a pressure suppression chamber,
A pressure release system for lowering the pressure in the reactor containment vessel, hydrogen contained in the exhaust gas released from this pressure release system, and oxygen injected from an external tank are forcibly mixed and burned. A reactor containment vessel venting device. 3. A reactor containment vessel for accommodating a reactor pressure vessel having a built-in core and having a pressure suppression chamber,
A reactor containment vessel venting device comprising a pressure release system for lowering the pressure of the reactor containment vessel and a cooling device for cooling the gas released from the pressure release system. 4. A reactor containment vessel for accommodating a reactor pressure vessel having a built-in core and having a pressure suppression chamber,
A pressure release system for lowering the pressure in the storage container, a storage container for temporarily storing gas released from the pressure release system, and a radioactive substance in the gas released from the storage container are reduced. A filter, a separator for separating radioactive substances in the gas that has passed through the filter, and a circulation system for circulating the radioactive substances separated by the separator to the reactor containment vessel and the storage vessel. Reactor containment vessel venting device. 5. The reactor containment vessel venting device according to claim 4, wherein a radioactive substance holding device is used in place of the circulation system for circulating the radioactive substance to the reactor containment vessel and the storage vessel.