JP6284889B2 - Radioactive substance removal filter device - Google Patents

Description

  The present invention relates to a radioactive substance removal filter device.

  In nuclear power plants, due to severe accidents, which are accidents that greatly exceed the design standard accident, a large amount of steam / gas containing radioactive material can be generated in the reactor containment vessel, and the pressure pressure of the reactor containment vessel can be exceeded. In order to minimize public exposure, it is necessary to remove radioactive materials from these vapors and gases (hereinafter referred to as vent gas) as much as possible and release them into the atmosphere.

  As a radioactive substance removal filter device for removing radioactive substances from vent gas, scrubbing with scrubbing water and collecting with a filter removes radioactive substances in the gas as much as possible, and as radioactive substance reducing gas from the exhaust tower via the outlet pipe There is a filter vent device for a containment vessel that discharges to the atmosphere (see, for example, Patent Document 1). Here, the vent gas is scrubbed by being released into the scrubbing water in the scrubber container, and the particulate radioactive material is removed. In the filter, gaseous radioactive substances are removed by chemical reaction and adsorption.

JP 2014-44118 A

  According to the filter vent device for the reactor containment vessel described above, the radioactive substance can be removed as much as possible from the vent gas generated by a severe accident or the like, so that it can be discharged into the atmosphere as a radioactive substance reducing gas. As a result, public exposure can be minimized.

  As described above, such a radioactive substance removal filter device operates in a severe accident, for example, and is in a standby state when the nuclear power plant is normally operated (normal time). Yes. Specifically, the scrubber container storing the pool water constituting the radioactive substance removing filter device and the filter are a sealed space by an isolation valve (inlet valve) provided at the inlet and a rupture disk provided at the outlet side. Is placed inside.

  For this reason, in the sealed space, there exists a possibility of becoming a high humidity state by the vapor | steam by the pool water in a scrubber container. When an adsorbent that constitutes a filter uses an adsorbent that easily takes in moisture due to its porous structure, there is a possibility that the removal performance of radioactive substances may be reduced due to moisture absorption in a high humidity environment.

  The present invention has been made based on the above-described matters, and an object of the present invention is to provide a radioactive substance removing filter device that can maintain a sealed space in which a filter is normally placed in a low humidity state.

In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. For example, the present application is a radioactive substance removal filter device that removes radioactive substances in vent gas discharged from a reactor containment vessel of a nuclear power plant. An inlet vent pipe having one end connected to the reactor containment vessel body and the other end connected to a scrubber vessel, and an inlet valve provided in the inlet vent pipe and closed during normal operation of the nuclear power plant. , Scrubbing water injected into the scrubber container and capable of capturing and holding particulate radioactive material in the vent gas, and an adsorbent storage container having one end connected to the upper part of the scrubber container and the other end connected to the adsorbent storage container Adsorption capable of capturing and holding gaseous radioactive material in the vent gas filled in the inlet piping and the adsorbent storage container and passed through the scrubbing water With the door in normal operation of the nuclear power plant, comprising a adsorbent drying retaining means for preventing moisture absorption of the adsorbent, the adsorbent drying holding means, the other end of the adsorbent containment inlet pipe In the provided lid structure, when there is no vent gas pressure from the scrubber vessel, the lid structure seals the opening of the adsorbent storage vessel inlet pipe .

  ADVANTAGE OF THE INVENTION According to this invention, the sealed space where the radioactive substance removal filter apparatus in a normal time is arrange | positioned can be hold | maintained in a low humidity state. As a result, the moisture absorption of the adsorbent constituting the filter can be suppressed, and the radioactive substance removal performance can be maintained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows schematic structure of the nuclear power plant provided with 1st Embodiment of the radioactive substance removal filter apparatus of this invention. It is a schematic diagram which shows the structure of the adsorption body storage container which comprises 1st Embodiment of the radioactive substance removal filter apparatus of this invention. It is a perspective view which shows the A section of the adsorption body storage container of FIG. 2A. It is a schematic diagram which shows 2nd Embodiment of the radioactive substance removal filter apparatus of this invention. It is a schematic diagram which shows 3rd Embodiment of the radioactive substance removal filter apparatus of this invention.

  Hereinafter, embodiments of the radioactive substance removing filter device of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a schematic configuration of a nuclear power plant provided with a first embodiment of a radioactive substance removing filter device of the present invention.
The radioactive substance removal filter apparatus in this Embodiment shows the example applied to a boiling water nuclear power plant. The boiling water nuclear power plant includes a reactor containment vessel 10 that surrounds a reactor pressure vessel 11 in a reactor building. An annular pressure suppression chamber 12 that stores cooling water is installed as a core cooling system (ECCS) at a position around the lower portion of the reactor containment vessel 10. The pressure suppression chamber 12 and the reactor containment vessel 10 are connected by a plurality of vent pipes 13 attached to a plurality of locations in the circumferential direction below the reactor containment vessel 10.

  A reactor core (not shown) loaded with a plurality of fuel assemblies (not shown) is arranged inside the reactor pressure vessel 11. The reactor pressure vessel 11 is connected to a main steam pipe 11A, a water supply pipe (not shown), and the like.

  The radioactive substance removal filter device 1 is provided in a line for venting the vent gas to the atmosphere through a pipe attached to the main body of the reactor containment vessel 10, and includes a scrubber vessel 1 A, a nozzle 2, an adsorbent containment vessel 3, A rupture disk 4 and an inlet valve 5 are provided.

  One end side of the inlet vent pipe 21 is connected to the main body of the reactor containment vessel 10, and the other end side is introduced into the scrubber vessel 1A. The inlet vent pipe 21 is closed during normal plant operation, and is provided with an inlet valve 5 that is opened when vent gas needs to be discharged from the reactor containment vessel 10. Further, a nitrogen injection pipe 25 is connected to the inlet vent pipe 21 downstream of the inlet valve 5. The nitrogen injection pipe 25 is provided with a normally closed nitrogen injection valve 25a.

The scrubber container 1A captures and holds the particulate radioactive substance in the vent gas, and stores scrubbing water 20 for scrubbing therein. In the present embodiment, in the scrubbing water 20, a nozzle 2 having one end connected to the introduced inlet vent pipe 21 is installed in the lower part of the scrubber container 1A. One end side of the adsorbent storage container inlet pipe 22 is connected to the upper part of the scrubber container 1 </ b> A , and the other end side is introduced into the adsorbent storage container 3.

  The adsorbent storage container 3 captures and holds a gaseous radioactive substance in the vent gas, and is filled with an adsorbent 15 that removes the gaseous radioactive substance by a chemical reaction and an adsorption action. The vent gas supplied via the adsorbent storage container inlet pipe 22 passes through the adsorbent 15 so that the gaseous radioactive substance is removed. One end side of the outlet vent pipe 23 is connected to the adsorbent storage container 3.

  The other end side of the outlet vent pipe 23 is connected to the rupture disk 4. Further, a nitrogen exhaust pipe 26 is connected to the outlet vent pipe 23. The nitrogen discharge pipe 26 is provided with a normally closed nitrogen discharge valve 26a. A discharge pipe 24 on the downstream side of the rupture disk 4 discharges vent gas from the exhaust tower 16 and the like to the atmosphere.

  By the way, as described in the problem to be solved, the radioactive substance removing filter device 1 is sealed by the inlet valve 5 and the rupture disk 4 when the nuclear power plant is normally operated (normal time). Configure the space. This sealed space is filled with nitrogen gas as a countermeasure against hydrogen explosion. Specifically, for example, nitrogen is injected from the nitrogen injection pipe 25 through the nitrogen injection valve 25a and discharged from the nitrogen discharge pipe 26 through the nitrogen discharge valve 26a before the operation of the nuclear power plant. The replacement is performed, and then the nitrogen injection valve 25a and the nitrogen discharge valve 26a are closed.

  In the space filled with the nitrogen gas, there is a possibility that a high humidity state may be caused by the steam generated by the scrubbing water 20 in the scrubber container 1A. When such a state occurs, the adsorbent 15 of the adsorbent storage container 3 may take in moisture in the normal state, which may reduce the removal performance of the radioactive substance, and the performance degradation was confirmed. In this case, there is a problem that the adsorbent needs to be replaced.

  The first embodiment of the radioactive substance removing filter device of the present invention is for solving such a problem. Specifically, a lid structure 30 is provided at the tip of the adsorbent storage container inlet pipe 22 introduced into the adsorbent storage container 3 as the adsorbent drying and holding means. This will be described below with reference to FIGS. 2A and 2B.

  FIG. 2A is a schematic view showing the configuration of the adsorbent storage container constituting the first embodiment of the radioactive substance removing filter device of the present invention, and FIG. 2B is a perspective view showing part A of the adsorbent storage container of FIG. 2A. is there. In FIG. 2A and FIG. 2B, the same reference numerals as those shown in FIG.

  As shown in FIG. 2A, the adsorbent storage container 3 removes the inlet 3a into which the vent gas is introduced via the adsorbent storage container inlet pipe 22 and the gaseous radioactive substance in the vent gas by a chemical reaction and an adsorption action. An adsorbing part 3b filled with the adsorbing body 15 and an outlet part 3c in which the vent gas that has passed through the inlet part and the adsorbing part stays are provided. One end side of the outlet vent pipe 23 is connected to the outlet portion 3c.

  As shown in FIGS. 2A and 2B, a lid structure 30 that can be opened and closed is provided at the tip of the adsorbent storage container inlet pipe 22 introduced into the inlet 3 a of the adsorbent storage container 3.

  The lid structure 30 is movable up and down by connecting a hinge mechanism portion 31 provided at the upper portion of the tip opening of the adsorbent storage container inlet pipe 22 and one end side to the hinge mechanism portion 31, and is provided at the inlet of the adsorbent storage container. The lower end length of the adsorbent storage container inlet pipe 22 is formed to be longer than the upper length at the lid portion 32 capable of sealing the front end opening of the pipe 22 and the front end opening of the adsorbent storage container inlet pipe 22. And a tapered portion 33.

Since the lid portion 32 is formed of a lightweight material, the lid portion 32 is pressed by the pressure of the vent gas when the vent gas flows from the scrubber container 1A or when nitrogen is replaced, and the hinge mechanism portion 31 opens upward. The vent gas flow is not hindered.

  Further, since the tapered portion 33 is provided at the tip opening of the adsorbent storage container inlet pipe 22, there is no vent gas pressure when the nuclear power plant is normally operated (normal time), and the lid portion 32 has its own weight. The taper part 33 is covered with. As a result, the tip opening of the adsorbent storage container inlet pipe 22 is sealed. As a result, since the inlet 3a of the adsorbent storage container 3 is sealed, it is possible to prevent the vapor generated from the scrubbing water 20 in the scrubber container 1A from flowing into the adsorbent storage container 3.

Next, operation | movement of 1st Embodiment of the radioactive substance removal filter apparatus of this invention is demonstrated using drawing.
In FIG. 1, when one of the main steam pipes 11A breaks down during normal operation of the nuclear power plant (hereinafter referred to as large LOCA), the steam generated in the reactor pressure vessel 11 flows out from the break opening and the reactor pressure The water level and pressure in the vessel 11 drop, and all the control rods are inserted into the reactor core, so the reactor stops. In this case, by using a residual heat removal system (RHR) which is one of the main facilities of the emergency core cooling system (ECCS), water injection into the reactor pressure vessel 11, spray injection into the reactor containment vessel 10, In addition, the pressure suppression chamber 12 can be cooled. By maintaining the coolant water level above the core by pouring water into the reactor pressure vessel 11, the large LOCA can be safely converged by removing heat from the reactor containment vessel 10 while stably cooling the core continuously. Can be made.

  However, as an accident exceeding the design standard accident, for example, when it is assumed that all AC power loss (SBO) occurs, the three functions of the RHR described above cannot be used, so the coolant in the reactor pressure vessel 11 is not used. As the water level cannot be maintained, the core is exposed on the surface of the water, the fuel loaded in the core is damaged, and steam and gas containing a large amount of radioactive material are released into the reactor containment vessel 10 and the accident progresses. The pressure and temperature in the reactor containment vessel 10 will be increased.

In order to prevent overheating and overpressure damage of the reactor containment vessel 10, radioactive materials are removed from the vent gas in the reactor containment vessel 10 as much as possible and released into the atmosphere.
Specifically, first, the inlet valve 5 is opened. Thereby, the vent gas containing the radioactive substance generated in the reactor containment vessel 10 is ejected from the nozzle 2 of the scrubber vessel 1A into the scrubbing water 20 through the inlet vent pipe 21. When the vent gas is mixed with the scrubbing water by the nozzle 2, the particulate radioactive material in the vent gas is captured and held in the scrubbing water and removed.

  The vent gas that has passed through the scrubbing water flows into the adsorbent storage container inlet pipe 22, opens the lid portion 32 of the lid structure 30 provided at the tip, and guides it to the inlet section 3 a of the adsorbent storage container 3. It is burned.

  The vent gas guided to the inlet portion 3a of the adsorbent storage container 3 passes through the adsorbing portion 3b filled with the adsorbent 15 and flows out from the outlet portion 3c to the outlet vent pipe 23. Here, the adsorbent 15 removes the gaseous radioactive substance in the vent gas by a chemical reaction and an adsorption action. The vent gas flowing out to the outlet vent pipe 23 flows into the rupture disk 4 and breaks and opens the rupture disk 4 to form a gas flow path together with the discharge pipe 24. Thus, the vent gas from which the gaseous radioactive material has been removed is released to the atmosphere via the outlet vent pipe 23, the rupture disk 4, the discharge pipe 24, the exhaust tower 16, and the like.

  As described above, in the present embodiment, since the lid structure 30 is provided at the tip of the adsorbent storage container inlet pipe 22 introduced into the adsorbent storage container 3 as the adsorbent drying and holding means, Even when an accident or the like occurs, radioactive substances can be removed from the vent gas as much as possible, and moisture absorption of the adsorbent constituting the filter can be suppressed during normal times. As a result, it is possible to prevent a reduction in the radioactive substance removal performance of the filter.

  According to the first embodiment of the radioactive substance removing filter device of the present invention described above, the sealed space in which the radioactive substance removing filter device 1 is arranged in a normal state can be maintained in a low humidity state. As a result, moisture absorption of the adsorbent 15 constituting the adsorbent storage container 3 can be suppressed, and the radioactive substance removal performance can be maintained.

  Hereinafter, a second embodiment of the radioactive substance removing filter device of the present invention will be described with reference to the drawings. FIG. 3 is a schematic view showing a second embodiment of the radioactive substance removing filter device of the present invention. In FIG. 3, the same reference numerals as those shown in FIGS. 1 and 2 are the same parts, and detailed description thereof is omitted.

  In the second embodiment of the radioactive substance removal filter device of the present invention, the configuration of the nuclear power plant and the arrangement of the radioactive substance removal filter device 1 are substantially the same as those in the first embodiment as shown in FIG. The adsorbent storage container 3 is not provided with a lid structure 30, a storage tank 6 for storing the scrubbing water 20, a scrubbing water supply pipe 8 for supplying the scrubbing water 20 from the storage tank 6 to the scrubber container 1A, and a scrubbing A tank stop valve 7 provided in the water supply pipe 8 is provided, and the difference is that the scrubbing water 20 is not stored in the scrubber vessel 1A during normal operation of the nuclear power plant.

  In the present embodiment, the water storage tank 6 is disposed at a position above the scrubber container 1A. Further, one end side of the scrubbing water supply pipe 8 is connected to the lower part of the water storage tank 6, and the other end side of the scrubbing water supply pipe 8 is connected to a side surface portion of the scrubber container 1A. Accordingly, the scrubbing water 20 can be supplied from the water storage tank 6 to the scrubber container 1A by gravity without requiring a pump or the like.

  In the present embodiment, a water storage tank 6 for storing scrubbing water 20 as adsorbent drying and holding means, a scrubbing water supply pipe 8 for supplying scrubbing water 20 from the water storage tank 6 to the scrubber vessel 1A, and a scrubbing water supply pipe 8 The scrubbing water 20 is not stored in the scrubber container 1A at a normal time.

  In the operation of the second embodiment of the radioactive substance removal filter device of the present invention, for example, when a severe accident as described above occurs, first, before opening the inlet valve 5, the tank stop valve 7 is opened. Is automatically or manually opened, and scrubbing water 20 is poured from the water storage tank 6 into the scrubber container 1A. Thereafter, the inlet valve 5 is opened to introduce the vent gas into the scrubber container 1A.

  As described above, in the present embodiment, since the configuration in which the scrubbing water 20 is not stored in the scrubber container 1A is normally used as the adsorbent drying and holding means, the moisture absorption of the adsorbent constituting the filter is normally performed. Can be suppressed. As a result, it is possible to prevent a reduction in the radioactive substance removal performance of the filter.

  According to the second embodiment of the radioactive substance removing filter device of the present invention described above, the same effects as those of the first embodiment described above can be obtained.

  Further, according to the second embodiment of the radioactive substance removing filter device of the present invention described above, the water storage tank 6 is disposed at a position above the scrubber container 1A, so that it is scrubbed by gravity without requiring a pump or the like. Water 20 can be supplied from the water storage tank 6 to the scrubber container 1A. As a result, even when the power source is lost due to a severe accident, the scrubbing water 20 can be reliably poured into the scrubber container 1A.

  Hereinafter, a third embodiment of the radioactive substance removal filter device of the present invention will be described with reference to the drawings. FIG. 4 is a schematic view showing a third embodiment of the radioactive substance removing filter device of the present invention. In FIG. 4, the same reference numerals as those shown in FIGS. 1 to 3 are the same parts, and detailed description thereof is omitted.

  In the third embodiment of the radioactive substance removal filter device of the present invention, the configuration of the nuclear power plant and the arrangement of the radioactive substance removal filter device 1 are substantially the same as those of the second embodiment, as shown in FIG. However, the water tank 6 is not arranged at a position above the scrubber vessel 1A, the pump 9 for supplying pressurized gas (nitrogen), one end connected to the upper part of the water tank 6, and the other end The difference is that a pressurized gas (nitrogen) supply pipe 9B connected to the discharge port of the pump 9 and a pump discharge valve 9A provided in the pressurized gas supply pipe 9B are provided.

  In the present embodiment, in addition to the constituent elements of the second embodiment as the adsorbent drying and holding means, the pump 9 capable of pressurizing the gas phase portion of the water storage tank 6 and the pump 9 to the water storage tank 6 are added. A pressurized gas supply pipe 9B capable of supplying a pressurized gas and a pump discharge valve 9A provided in the pressurized gas supply pipe 9B are provided, and the scrubbing water 20 is not stored in the scrubber container 1A at a normal time. .

  In the operation of the third embodiment of the radioactive substance removing filter device of the present invention, for example, when a severe accident as described above occurs, first, before opening the inlet valve 5, the tank stop valve 7 is opened. Is automatically or manually opened, and then the pump 9 is started and the pump discharge valve 9A is opened to pressurize the gas phase portion of the water storage tank 6 so that the scrubbing water 20 is discharged from the water storage tank 6. Water is poured into the scrubber container 1A. Thereafter, the inlet valve 5 is opened to introduce the vent gas into the scrubber container 1A.

  According to the third embodiment of the radioactive substance removing filter device of the present invention described above, the same effects as those of the first embodiment described above can be obtained. Moreover, it is applicable when the water storage tank 6 cannot be installed at a position higher than the radioactive substance removal filter device 1 due to restrictions on arrangement.

  In the present embodiment, the example in which the gas phase portion of the water storage tank 6 is pressurized by the pump 9 has been described. However, the present invention is not limited to this. For example, instead of the pump 9, a compressed air source, a valve, and piping may be provided.

  Note that the present invention is not limited to the first to third embodiments described above, and includes various modifications. The above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to the one having all the configurations described. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is also possible to add, delete, or replace another configuration for a part of the configuration of each embodiment.

1: Scrubber container, 2: nozzle, 3: adsorbent storage container, 4: rupture disk,
5: Inlet valve, 6: Water storage tank, 7: Tank stop valve, 8: Scrubbing water supply pipe, 9: Pump, 9A: Pump discharge valve, 9B: Pressurized gas supply pipe, 10: Reactor containment vessel, 11: Reactor pressure vessel, 12: pressure suppression chamber, 13: vent pipe, 15: adsorbent, 16: exhaust tower, 20: scrubbing water, 21: inlet vent piping, 22: adsorbent storage vessel inlet piping, 23: outlet vent Piping, 24: exhaust piping, 25: nitrogen injection piping, 26: nitrogen exhaust piping, 30: lid structure, 31: hinge mechanism , 32: lid, 33: taper

Claims (5)

A radioactive substance removal filter device that removes radioactive substances in vent gas discharged from a nuclear reactor containment vessel,
One end connected to the reactor containment vessel body, and the other end connected to a scrubber vessel, inlet vent piping,
An inlet valve provided in the inlet vent pipe and closed during normal operation of the nuclear power plant;
Scrubbing water that is poured into the scrubber vessel and can capture and retain particulate radioactive material in the vent gas;
One end of the scrubber container is connected to the upper part of the scrubber container, and the other end of the adsorbent container is connected to the adsorbent container.
An adsorbent capable of trapping and holding a gaseous radioactive substance in a vent gas filled in the adsorbent storage container and passed through the scrubbing water;
During normal operation of the nuclear power plant, comprising an adsorbent dry holding means for preventing the adsorbent from absorbing moisture ,
The adsorbent drying and holding means is a lid structure provided at the other end of the adsorbent storage container inlet pipe,
The radioactive substance removing filter device , wherein when there is no vent gas pressure from the scrubber container, an opening of the adsorbent storage container inlet pipe is sealed by the lid structure . A radioactive substance removal filter device that removes radioactive substances in vent gas discharged from a nuclear reactor containment vessel,
One end connected to the reactor containment vessel body, and the other end connected to a scrubber vessel, inlet vent piping,
An inlet valve provided in the inlet vent pipe and closed during normal operation of the nuclear power plant;
Scrubbing water that is poured into the scrubber vessel and can capture and retain particulate radioactive material in the vent gas;
One end of the scrubber container is connected to the upper part of the scrubber container, and the other end of the adsorbent container is connected to the adsorbent container.
An adsorbent capable of trapping and holding a gaseous radioactive substance in a vent gas filled in the adsorbent storage container and passed through the scrubbing water;
During normal operation of the nuclear power plant, comprising an adsorbent dry holding means for preventing the adsorbent from absorbing moisture,
The adsorbent dry holding means includes:
A water storage tank for storing the scrubbing water;
A scrubbing water supply pipe for injecting scrubbing water from the water storage tank to the scrubber container;
And a tank check valve provided in the scrubbing water supply pipe,
In the normal operation of the nuclear power plant, the scrubbing water is not stored in the scrubber vessel. The radioactive substance removal filter device according to claim 2 ,
The radioactive water removing filter device, wherein the water storage tank is disposed at a position above the scrubber container. The radioactive substance removal filter device according to claim 2 ,
A pump capable of pressurizing the gas phase of the water storage tank;
A pressurized gas supply pipe capable of supplying pressurized gas from the pump to the water storage tank;
A radioactive substance removal filter device comprising: a pump discharge valve provided in the pressurized gas supply pipe. The radioactive substance removal filter device according to claim 2 ,
Compressed air supply piping capable of supplying compressed air from a compressed air source to the water storage tank;
A radioactive substance removal filter device comprising: a supply stop valve provided in the compressed air supply pipe.

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