JP2020118612A - System and method for processing gaseous waste - Google Patents

Abstract

To provide a system and method for processing gaseous waste, capable of simplifying and downsizing a structure while maintaining the processing capability of radioactive noble gas.SOLUTION: A system 1 for processing gaseous waste comprises: a main passage 2 constituted so as to collect gas including gaseous waste formed in the reactor 101 of a nuclear power plant to guide the gas into the external environment of the nuclear power plant; a permeable membrane 3 provided on the main passage 2 and having characteristics of easily permeating water vapor and hydrogen gas and meanwhile hardly permeating xenon gas and krypton gas; a bypass passage 6 having one end side connected to a portion of the main passage 2 on the upstream side from the permeable membrane 3 and the other end side connected to a portion of the main passage 2 on the downstream side from the permeable membrane 3 and capable of circulating the gas prevented from permeating the permeable membrane 3 by bypassing the permeable membrane 3; and an opening/closing valve 7 provided on the bypass passage 6 and opening and closing the bypass passage 6.SELECTED DRAWING: Figure 1

Description

The present invention relates to a gas waste treatment facility for a nuclear power plant and a gas waste treatment method.

In a nuclear power plant with a boiling water reactor, the cooling water is heated by the thermal energy generated by the nuclear fission reaction of the nuclear fuel in the reactor core to generate steam, and the generated steam is directly supplied to the turbine as a power source. .. In the nuclear reactor, irradiation of radiation such as neutrons and γ rays generated by nuclear fission causes radiolysis of a part of the cooling water. By this radiolysis, hydrogen gas and oxygen gas are produced, and ¹⁶ N, ³ H, and ¹⁹ O are produced as by-products. These hydrogen gas, oxygen gas, ¹⁶ N, ³ H, and ¹⁹ O are carried to the condenser through the turbine together with the steam generated in the furnace. In the condenser, the steam is cooled and returned to the condensed water. On the other hand, non-condensable gases such as hydrogen gas, oxygen gas, ¹⁶ N, ³ H, and ¹⁹ O are accumulated in the condenser. ^{Since 16} N, ³ H, and ¹⁹ O are radionuclides with a short half-life, the radioactivity decays while staying inside the condenser (hot well). The condenser is designed to have a volume that allows it to stay in the hot well until the radioactivity levels of these radionuclides have decayed below a certain level.

In the core, fission products are produced as the fission of nuclear fuel progresses. This fission product also contains radioactive noble gases such as krypton (Kr) and xenon (Xe). Fission products containing radioactive noble gases are usually confined within the fuel cladding. However, the fuel cladding may have, albeit very low, a small hole, called a pinhole. In this case, the radioactive rare gas leaks to the outside of the fuel cladding tube through the pinhole. This radioactive noble gas is mixed with the steam in the furnace and is carried to the condenser through the turbine together with the steam, and is accumulated inside the condenser together with the above hydrogen gas, oxygen gas, ¹⁶ N, ³ H and ¹⁹ O. To be done.

Non-condensable gases such as hydrogen gas, oxygen gas, ¹⁶ N, ³ H, ¹⁹ O and radioactive noble gases that stay inside the condenser are called gaseous waste. In a nuclear power plant having a boiling water reactor, the gas waste is treated by a gas waste treatment facility in order to reduce the volume of the gas waste and attenuate the radioactivity. As a gas waste treatment facility, for example, there is one described in Patent Document 1. In the gas waste treatment system described in Patent Document 1, the gas waste extracted from the condenser by the air extractor is introduced together with the driving steam into the exhaust gas preheater to be heated, and then the exhaust gas recombiner is used to discharge the gaseous waste. The hydrogen gas and oxygen gas of the above are recombined by the action of the catalyst to generate steam (recombined water), and then the driving steam and the recombined water (steam) are cooled by the exhaust gas condenser and condensed as condensed water. The remaining gaseous waste is dehumidified with a dehumidifying cooler and cooled. After that, the dried low-temperature gas waste is passed through an activated carbon type rare gas hold-up device, passed through an exhaust gas filter, guided to an exhaust stack by an exhaust gas extractor, and discharged into the atmosphere.

JP, 2010-2278, A

The rare gas hold-up device as described in Patent Document 1 is a radioactive rare gas, which is obtained by physically adsorbing and desorbing a radioactive rare gas having a low reactivity with Kr or Xe in the gaseous waste with activated carbon and holding it. It attenuates the radioactivity of. The device needs to accommodate a large amount of activated carbon so that the radioactive noble gas can be retained for a predetermined period of time, which is a very large structure. For example, a plurality of devices each having a diameter of 3 m and a height of 4 m are connected to each other. This huge activated carbon type rare gas hold-up device is one of the factors that increase the cost of the gaseous waste treatment system.

Further, in recent years, due to improvement in the performance of the fuel cladding tube, leakage of radioactive noble gas from the fuel cladding tube is extremely rare. If no radioactive noble gas leaks from the fuel cladding, there is no need to treat the gaseous waste with a noble gas holdup device. Because, in this case, the gaseous waste is composed of hydrogen gas, oxygen gas, and radionuclides with a short half-life such as ¹⁶ N, ³ H, and ¹⁹ O, whose radioactivity levels have already decayed in the hot well of the condenser. Because it is done. That is, at present, the rare gas hold-up device is configured to be prepared for leakage of radioactive rare gas in the unlikely event.

Further, in the gas waste treatment facility equipped with the rare gas hold-up device as described in Patent Document 1, there is a device required by installing the rare gas hold-up device. The configuration becomes complicated. This leads to an increase in the cost of the gas waste treatment facility. Specifically, it is as follows.

Since the gaseous waste contains hydrogen gas and oxygen gas, in the gaseous waste treatment system described in Patent Document 1, in order to reduce the concentration of hydrogen gas for the purpose of explosion protection, steam is turned into gaseous waste. Mixed. However, in the activated carbon type rare gas hold-up device, when the gas to be treated contains a large amount of water, the ability of the activated carbon is not sufficiently exhibited. Therefore, after heating the gas waste diluted with water vapor in the exhaust gas preheater, recombination water (water vapor) is generated from the hydrogen gas and oxygen gas of the gas waste in the exhaust gas recombiner, and is generated from the gas waste. The water vapor and the water vapor diluted with the gaseous waste are collected by the exhaust gas condenser. Then, after the moisture contained in the gas waste is sufficiently removed by the dehumidifying cooler, the gas waste is introduced into the activated carbon type rare gas hold-up device. Thus, it is necessary to treat the water vapor and the moisture of the gaseous waste before introducing the gaseous waste into the activated carbon rare gas hold-up device.

As described above, in the gas waste treatment facility, the rare gas hold-up device for treating the radioactive rare gas causes a cost increase. On the other hand, however, if the radioactive noble gas leaks from the fuel cladding tube, the gas waste treatment facility must release the radioactive noble gas to the external environment with its radioactivity attenuated.

The present invention has been made to solve the above problems, and an object thereof is a gas waste treatment facility capable of achieving simplification and miniaturization of a configuration while maintaining a treatment function of radioactive noble gas. And a method for treating gaseous waste.

The present application includes a plurality of means for solving the above problems, and one example thereof is configured to take in a gas containing a gas waste generated in a nuclear reactor of a nuclear power plant and guide it to the external environment of the nuclear power plant. And a permeable membrane that is provided on the main route and has a property that water vapor and hydrogen gas easily permeate while xenon gas and krypton gas hardly permeate, and one end side of the permeable membrane of the main route Is also connected to the upstream side portion and the other end side is connected to the downstream side portion of the main passage from the permeable membrane, so that a gas that cannot pass through the permeable membrane can flow around the permeable membrane. And a switching valve that is provided on the bypass path and that opens and closes the bypass path.

According to the present invention, a part of the gaseous waste is released to the external environment through the permeable membrane, while the permeable membrane separates the radioactive noble gases of xenon gas and krypton gas from the gaseous waste to remove the radioactive noble gas. After being temporarily retained, it can be released to the external environment via the bypass route. That is, a permeable membrane having a size corresponding to the processing flow rate of the gaseous waste and a bypass path bypassing the permeable membrane are required as a configuration for treating the gaseous waste, but a rare gas hold-up device and devices associated therewith are not required. Is. Therefore, the structure of the gas waste treatment facility can be simplified and downsized while maintaining the function of treating the radioactive noble gas.
Problems, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

1 is a system diagram showing a schematic configuration of a nuclear power plant including a first embodiment of a gas waste treatment facility of the present invention. It is a cross-sectional schematic diagram which shows the structure of the filter module which comprises a part of 1st Embodiment of the gaseous waste processing equipment of this invention. It is a systematic diagram which shows the structure of the modification of 1st Embodiment of the gaseous waste processing equipment of this invention. It is a system diagram which shows the structure of 2nd Embodiment of the gaseous waste processing equipment of this invention. It is a system diagram which shows the structure of 3rd Embodiment of the gaseous waste processing equipment of this invention. It is a system diagram which shows the structure of 4th Embodiment of the gaseous waste processing equipment of this invention. It is a system diagram which shows the structure of 5th Embodiment of the gaseous waste processing equipment of this invention. It is a system diagram which shows schematic structure of the nuclear power plant containing other embodiment of the gaseous waste processing equipment of this invention.

Embodiments of a gas waste treatment facility and a gas waste treatment method of the present invention will be described below with reference to the drawings.

[First Embodiment]
First, the configuration of a nuclear power plant including the first embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a system diagram showing a schematic configuration of a nuclear power plant including a first embodiment of a gas waste treatment facility of the present invention, and FIG. 2 is an example of a first embodiment of a gas waste treatment facility of the present invention. It is a cross-sectional schematic diagram which shows the structure of the filter module which comprises a part.

In FIG. 1, a boiling water nuclear power plant includes a nuclear reactor 101 that generates steam, a steam turbine 102 that is driven by steam generated in the nuclear reactor 101, and condensate that condenses exhaust steam from the steam turbine 102. The reactor 103 includes a main steam pipe 104 that connects the reactor 101 and the steam turbine 102, and a condensate/water supply system 105 that supplies the water generated in the condenser 103 to the reactor 101. The condensate/water supply system 105 includes, in order from the upstream side, a condensate pump 108 provided in the condensate pipe 107 and a water supply pump 110 provided in the water supply pipe 109.

In the nuclear reactor 101, the nuclear fuel loaded in the core 101a generates heat due to a fission reaction, so that the cooling water in the reactor boils and steam is generated. The steam generated in the nuclear reactor 101 is introduced into the steam turbine 102 via the main steam pipe 104. As a result, the steam turbine 102 rotationally drives a generator (not shown). The steam that has driven the steam turbine 102 is cooled by the condenser 103 and returns to water. The water generated in the condenser 103 is supplied again to the nuclear reactor 101 by the condensate pump 108 and the water supply pump 110 via the condensate pipe 107 and the water supply pipe 109 of the condensate/water supply system 105.

In the nuclear reactor 101, hydrogen gas and oxygen gas are generated from a part of the cooling water and ¹⁶ N, ³ H, and ¹⁹ O are generated as by-products by irradiation of radiation generated by the nuclear fission reaction of nuclear fuel. It These hydrogen gas, oxygen gas, ¹⁶ N, ³ H, and ¹⁹ O are carried to the condenser 103 via the steam turbine 102 together with the steam generated in the nuclear reactor 101. In the condenser 103, the steam is cooled and returned to water. On the other hand, non-condensable gases such as hydrogen gas, oxygen gas, ¹⁶ N, ³ H, and ¹⁹ O are accumulated in the condenser 103. ¹⁶ N, ³ H, and ¹⁹ O are radionuclides having a short half-life, and the radioactivity is attenuated while staying inside the condenser 103 (hot well). The condenser 103 is designed to have a volume capable of staying in the hot well until the radioactivity of these radionuclides decays below a predetermined level.

In the core 101a of the nuclear reactor 101, fission products are produced as the nuclear fission reaction of the nuclear fuel progresses. The fission products contain radioactive noble gases such as krypton gas and xenon gas. The fission product containing the radioactive noble gas is usually confined in a fuel cladding tube (not shown). However, the fuel cladding may have, albeit very low, a small hole, called a pinhole. In this case, the radioactive rare gas leaks to the outside of the fuel cladding tube through the pinhole. The leaked radioactive noble gas is mixed with the steam generated in the nuclear reactor 101 and is carried to the condenser 103 through the steam turbine 102 together with the steam. As a result, the non-condensable radioactive noble gas having poor reactivity is accumulated inside the condenser 103 together with the above-mentioned hydrogen gas, oxygen gas, ¹⁶ N, ³ H, and ¹⁹ O.

Non-condensable gases such as hydrogen gas, oxygen gas, ¹⁶ N, ³ H, ¹⁹ O, and radioactive noble gas that stay in the condenser 103 are called gaseous waste. The nuclear power plant includes a gas waste treatment facility 1 that attenuates the radioactivity of the gas waste and then discharges the gas waste to the environment outside the nuclear power plant. The gas waste treatment facility 1 is provided on the main route 2 configured to take in non-condensable gaseous waste together with water vapor to the external environment of the nuclear power plant, and is provided on the main route 2 so that water vapor and hydrogen gas permeate therethrough. And a filter module 3 including a permeable membrane having a characteristic that xenon gas and krypton gas are less likely to permeate.

The main route 2 according to the present embodiment has a plurality of (two in FIG. 1) branch routes 2a connected in parallel. A storage tank 4 is provided in the middle of each branch path 2a. A filter module 3 is arranged inside each storage tank 4, and the storage tank 4 constitutes a part of the branch path 2a on the upstream side of the filter module 3. This main path 2 is composed of an extraction line 21, a plurality of first branch lines 22, a plurality of storage tanks 4, a plurality of second branch lines 23, an exhaust line 24, and an exhaust tower 25 in this order from the upstream side. Has been done.

The extraction pipe line 21 is a pipe line connected to the condenser 103, and takes in the gaseous waste accumulated in the condenser 103 together with the steam. The first branch pipeline 22 is a pipeline branching from the downstream end of the extraction pipeline 21 and connected to the storage tank 4, and constitutes the upstream side portion of the branch pathway 2a. The first branch conduit 22 guides the gaseous waste and water vapor flowing through the extraction conduit 21 to the storage tank 4 (filter module 3). The storage tank 4 temporarily stores gas that cannot pass through the permeable membrane of the filter module 3. The second branch pipeline 23 is provided with the filter module 3 at its upstream end, and is connected to the storage tank 4 on the upstream side so that the filter module 3 is arranged in the storage tank 4. The second branch pipeline 23 constitutes a downstream side portion of the branch pathway 2 a, and is a pipeline through which gas that has permeated the permeable membrane of the filter module 3 flows. The exhaust pipe line 24 is a pipe line in which a plurality of second branch pipe lines 23 join at the upstream end thereof and the downstream side thereof is connected to the exhaust tower 25. The exhaust pipe line 24 joins the gases flowing through the plurality of second branch pipe lines 23 and guides them to the exhaust tower 25. The exhaust tower 25 discharges the gas flowing from the exhaust pipe line 24 to the external environment of the nuclear power plant and diffuses it.

The extraction pipe line 21 is provided with a main pump 11 that sucks gaseous waste and steam from the condenser 103 and sends them to the storage tank 4 (filter module 3). The branch path 2a is provided with a switching valve 12 that switches so that any one of the plurality of branch paths 2a connected in parallel is in communication. The switching valve 12 is, for example, a three-way valve provided at a branch portion of the plurality of first branch pipelines 22. In each storage tank 4, a radiation detector 13 that detects the radiation dose of the gas stored in the storage tank 4 and a pressure detector 14 that detects the pressure of the gas stored in the storage tank 4 are arranged.

A bypass path 6 that allows a gas that cannot pass through the permeable membrane of the filter module 3 to flow around the filter module 3 is connected to each branch path 2a. In the bypass path 6 according to the present embodiment, one end side is connected to the storage tank 4 (a part of the branch path 2a on the upstream side of the filter module 3) and the other end side is the second branch pipeline 23 (the branch path 2a). This is a pipe line connected to the downstream side of the filter module 3). Each bypass path 6 is provided with an on-off valve 7 that opens and closes the bypass path 6 (pipe line). A check valve 15 is provided in a portion of each branch passage 2a on the downstream side of the connection portion with the bypass passage 6. The check valve 15 allows the flow of gas toward the exhaust pipe line 24, while blocking the flow of gas from different branch paths 2a.

As shown in FIG. 2, for example, the filter module 3 closes a permeable membrane in which a large number of hollow fiber membranes 31 are bundled, a cylindrical container 32 that houses the permeable membrane, and openings on both sides of the container 32. It is composed of a lid 33. Both ends of the large number of hollow fiber membranes 31 are supported by the container 32 via the support members 34, respectively. Both support members 34 are attached to the container 32 so as to seal the inside of the container 32. An inlet 36 into which gaseous waste flows is provided on one side (left side in FIG. 2) of the lid 33. The other (right side in FIG. 2) of the lid 33 is provided with a first outlet 37 through which a gas of the gas waste that cannot pass through the permeable membrane flows out. The container 32 is provided with a second outlet 38 through which the gas of the gas waste that has passed through the permeable membrane flows out. The filter module 3 has a configuration in which the lid 33 can be removed to take out and replace the permeable membrane in a state in which a large number of hollow fiber membranes 31 are bundled. The filter module 3 is connectable to a pipe and is an extremely small structure as compared with a rare gas holdup device.

The permeable membrane is, for example, a molecular sieving membrane that has a network structure at the molecular level and selectively permeates a specific gas by utilizing the difference in the molecular diameter of various gases. The molecular sieving membrane of the filter module 3 according to the present embodiment allows water vapor (having a molecular diameter of, for example, about 0.265 nm) and hydrogen gas (having a molecular diameter of, for example, about 0.289 nm) to easily pass through, while xenon gas (having a molecular diameter of about 0.289 nm). (For example, about 0.396 nm) and krypton gas (having a molecular diameter of about 0.360 nm) are less likely to permeate.

The oxygen gas permeation performance of the molecular sieving membrane can be set to easily permeate or difficult to permeate as necessary. For example, the molecular sieving film is set to allow oxygen gas to pass through.

As the molecular sieving film, there are a polymer film formed of a material containing polyimide as a main component, a ceramic film formed of a material containing silicon nitride as a main component, and a graphene oxide film formed of a material containing carbon as a main component. It is preferred to use any of the three types of membranes. The molecular sieving film using a graphene oxide film is characterized in that it has the highest performance of separating xenon gas and krypton gas from other gases among the above three types of films. A molecular sieving membrane using a polymer membrane is characterized in that it has a relatively high ability to separate xenon gas and krypton gas from other gases, and also has a high water vapor permeation ability. A molecular sieving film using a ceramic film is characterized by having high strength and high heat resistance.

Next, a method of treating gaseous waste in the first embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIGS. 1 and 2. First, a case where the radioactive noble gas is confined in the fuel cladding tube and is not mixed with the water vapor in the reactor will be described.

In the gas waste treatment facility 1 according to the present embodiment, the switching valve 12 is in a state in which any one of the plurality (two in FIG. 1) of the branch paths 2a is in communication. For example, as shown in FIG. 1, the first branch conduit 22 of the upper branch path 2 a communicates with the extraction conduit 21. The on-off valves 7 provided in each bypass path 6 are normally all closed. That is, all bypass paths 6 are blocked.

In this case, the gaseous waste staying in the condenser 103 is composed of hydrogen gas, oxygen gas, ¹⁶ N, ³ H, ¹⁹ O, etc., whose radioactivity has been attenuated, and xenon gas and krypton gas are generated. Does not include. This gas waste is extracted into the extraction line 21 of the main path 2 by the main pump 11 together with the water vapor in the condenser 103. The gaseous waste and steam extracted in the extraction pipe line 21 are guided to the upper storage tank 4 via the upper first branch pipe line 22 selected by the switching valve 12.

Of the water vapor and the gaseous waste that have flowed into the storage tank 4, hydrogen gas passes through the permeable membrane of the filter module 3. The oxygen gas in the gaseous waste may or may not permeate the permeable membrane depending on the permeation performance of the permeable membrane. The gas containing water vapor and hydrogen gas that has permeated the permeable membrane of the filter module 3 passes through the upper second branch pipe 23 (downstream side portion of the upper branch passage 2a) and the exhaust pipe 24 and is discharged from the exhaust tower 25 to the nuclear power source. Disperse into the environment outside the plant. Since all the on-off valves 7 are closed, the gas flowing into the storage tank 4 is not discharged from the bypass path 6 to the external environment without passing through the filter module 3.

Next, a case where radioactive noble gases such as xenon gas and krypton gas leak outside the fuel cladding tube will be described. In this case, the gaseous waste staying in the condenser 103 contains radioactive noble gases such as xenon gas and krypton gas in addition to the above-mentioned gases.

The gaseous waste that remains in the condenser 103 is guided to the upper storage tank 4 together with the steam, as described above. As described above, the hydrogen gas in the gaseous waste flowing into the storage tank 4 permeates the permeable membrane of the filter module 3 together with the water vapor and is discharged to the external environment of the nuclear power plant. On the other hand, xenon gas and krypton gas of the gaseous waste cannot pass through the permeable membrane and remain in the storage tank 4. Since all the on-off valves 7 are closed, xenon gas and krypton gas are not discharged to the external environment via the bypass path 6. As described above, since the gas discharged to the external environment does not contain the radioactive noble gases such as xenon gas and krypton gas, the external environment is not affected by the radioactivity.

If the radioactive noble gas of xenon gas and krypton gas cannot pass through the permeable membrane and stays in the storage tank 4, the concentration of the radioactive noble gas in the storage tank 4 increases. In this case, the radiation detector 13 in the storage tank 4 detects an increase in ambient dose. Thereby, the operator of the nuclear plant can recognize that the radioactive noble gas has leaked from the inside of the fuel cladding tube.

The radioactive noble gas that cannot pass through the permeable membrane is temporarily retained in the storage tank 4 until its radioactivity is attenuated to a predetermined level. When the detection value of the radiation detector 13 is lower than a predetermined value (when it is confirmed that the radioactivity of the radioactive noble gas is attenuated to a safe level), the storage tank 4 holding the radioactive noble gas is connected. The open/close valve 7 of the bypass path 6 being opened is opened. As a result, the radioactive rare gas held in the storage tank 4 is discharged from the exhaust tower 25 to the external environment of the nuclear power plant via the bypass path 6, the second branch pipeline 23, and the exhaust pipeline 24, and diffuses. In this case, since the radioactivity of the radioactive noble gas has already dropped to a safe level, the radioactivity will not affect the external environment.

In addition, when the permeable membrane of the filter module 3 has a characteristic that oxygen gas is difficult to permeate, the storage tank 4 contains the radioactive noble gas and the oxygen gas of the waste gas. In this case, when the radioactive noble gas is discharged to the external environment via the bypass route 6, the oxygen gas is also discharged to the external environment.

It is also assumed that the radioactive noble gas continuously leaks outside the fuel cladding tube. In this case, the radioactive rare gas that cannot pass through the permeable membrane is gradually accumulated in the storage tank 4, and the pressure of the radioactive rare gas in the storage tank 4 rises. In this case, it is necessary to prevent the pressure in the storage tank 4 from reaching the pressure resistance of the storage tank 4.

In the present embodiment, the pressure detection value in the storage tank 4 detected by the pressure detector 14 provided in the storage tank 4 is monitored. When the detected value exceeds a predetermined value, the gaseous waste is introduced into another storage tank 4 (lower storage tank 4 in FIG. 1) different from the storage tank 4 holding the radioactive noble gas. Switch to be done. That is, the switching valve 12 is switched so that one branch path 2a (the upper branch path 2a in FIG. 1) communicates with another branch path 2a (the lower branch path 2a in FIG. 1).

In the lower storage tank 4 on the branch path 2a selected by the switching valve 12, hydrogen gas in the gas waste permeates the permeable membrane of the filter module 3 together with water vapor, as in the case of the upper storage tank 4. Then, the gas is discharged from the exhaust tower 25 to the external environment of the nuclear power plant via the second branch pipe line 23 and the exhaust pipe line 24 of the lower branch passage 2a. The radioactive noble gas of the gaseous waste remains in the storage tank 4 without being able to pass through the permeable membrane. Since all the on-off valves 7 are closed, no radioactive rare gas is discharged to the external environment via the bypass path 6.

At this time, in the upper storage tank 4 holding the radioactive noble gas, the gas waste does not flow in due to the switching of the switching valve 12, and the pressure does not rise any more. Further, by continuously maintaining the switching state of the branch route 2a for a predetermined time or longer, the radioactivity of the radioactive noble gas held in the upper storage tank 4 is attenuated. As described above, when the detection value of the radiation detector 13 becomes lower than the predetermined value, the upper opening/closing valve 7 is opened and the gas containing the radioactive noble gas held in the upper storage tank 4 is changed to the upper side. It is discharged to the environment outside the nuclear power plant via the bypass route 6. As a result, in the upper storage tank 4, the pressure is lowered, and the gaseous waste is allowed to flow in again.

In the lower storage tank 4 into which gaseous waste and water vapor are flowing, as in the case of the upper storage tank 4, radioactive noble gas that cannot pass through the permeable membrane is gradually accumulated, and The pressure of radioactive noble gas rises. When the pressure detection value of the lower storage tank 4 exceeds a predetermined value, another branch route 2a (upper branch route 2a in FIG. 1) different from the currently selected branch route 2a is communicated. The switching valve 12 is switched to switch the storage tank 4 for introducing the gaseous waste from the lower storage tank 4 to the upper storage tank 4. The subsequent steps are the same as the steps described above.

In the present embodiment, since the plurality of storage tanks 4 are arranged in parallel, the gas waste is introduced into any one of the plurality of storage tanks 4 and the permeable membrane of the filter module 3 is introduced. On the other hand, it is possible to temporarily hold the radioactive noble gas that cannot pass through the permeable membrane in the other storage tank 4 to reduce its radioactivity below a predetermined level. Therefore, since it is possible to continuously discharge the gaseous waste to the external environment while attenuating the radioactivity of the radioactive noble gas by the plurality of storage tanks 4 arranged in parallel, it is possible to continuously operate the gaseous waste treatment facility 1. is there.

Further, in the present embodiment, only the radioactive rare gas that may be contained in the gaseous waste is efficiently separated from the gaseous waste by the permeable membrane and temporarily stored in the storage tank 4 to reduce the radioactivity. While attenuating, water vapor or hydrogen gas having no radioactivity is actively discharged to the external environment without being held in the storage tank 4, so the capacity of the storage tank 4 is determined only by considering gas that cannot pass through the permeable membrane. You can do it. Therefore, the storage tank 4 can be significantly downsized as compared with the existing rare gas holdup device.

Further, in the present embodiment, since the radioactive noble gas is stored in the storage tank 4 while being pressurized by the main pump 11, the volume of the radioactive noble gas is reduced accordingly. Therefore, the storage tank 4 can be further downsized.

Further, in the present embodiment, since the permeable membrane (molecular sieving membrane) of the filter module 3 is used as a structure for treating the gaseous waste containing the radioactive noble gas, a special matter is required before introducing the gaseous waste into the permeable membrane. No processing is necessary. Therefore, the structure of the gas waste treatment facility 1 is simple because a structure such as a moisture removing device unlike the case of using the rare gas hold-up device is unnecessary.

In addition, in the present embodiment, the gas waste treatment facility 1 is configured so that the gas waste containing hydrogen gas that has accumulated in the condenser 103 is taken into the main path 2 (extraction line 21) together with the steam. ing. That is, the gaseous waste is taken into the gaseous waste treatment facility 1 in a state of being diluted with water vapor. Therefore, compared with the case where only the gaseous waste is taken into the gaseous waste treatment facility 1, the concentration of hydrogen gas in the gas flowing through the main path 2 is lower by the concentration of water vapor, and the possibility of hydrogen combustion is reduced. can do.

According to the first embodiment of the gas waste treatment facility of the present invention described above, a part of the gas waste is released to the external environment through the permeable membrane of the filter module 3, while xenon in the gas waste is discharged. It is possible to separate the radioactive noble gas of the gas and the krypton gas by the permeable membrane to temporarily hold the radioactive noble gas, and then release the radioactive noble gas to the external environment via the bypass path 6. That is, a permeable membrane having a size corresponding to the flow rate of the gaseous waste and a bypass path 6 that bypasses the permeable membrane are required as a configuration for treating the gaseous waste. It is unnecessary. Therefore, the structure of the gas waste treatment facility 1 can be simplified and downsized while maintaining the function of treating the radioactive noble gas. As a result, the cost of the gas waste treatment facility 1 can be reduced.

Further, according to the present embodiment, by using a polymer film containing polyimide as a main component as the molecular sieving film (permeation film) of the filter module 3, the filter module 3 has high separation performance for xenon gas and krypton gas and High water vapor permeation performance can be obtained.

Further, according to the present embodiment, by using a ceramic film containing silicon nitride as a main component as the molecular sieving film (permeable film) of the filter module 3, the filter module 3 can obtain high strength and heat resistance. ..

Further, according to the present embodiment, by using the graphene oxide film containing carbon as the main component as the molecular sieving film (permeation film) of the filter module 3, the filter module 3 has a particularly excellent separation of xenon gas and krypton gas. You can get performance.

[Modification of First Embodiment]
Next, a modified example of the first embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIG. FIG. 3 is a system diagram showing a configuration of a modified example of the first embodiment of the gaseous waste treatment facility of the present invention. Note that, in FIG. 3, the same reference numerals as those shown in FIGS. 1 and 2 denote the same parts, and thus detailed description thereof will be omitted.

The modification of the first embodiment of the gaseous waste treatment facility of the present invention shown in FIG. 3 is different from the first embodiment in that hydrogen gas and oxygen among the gaseous wastes flowing through the main route 2 are used. It further comprises a hydrogen treatment device 17 for generating water vapor from the gas. The other configurations of the modification of the first embodiment are the same as the configurations of the first embodiment.

The hydrogen treatment device 17 of the gas waste treatment facility 1A is, for example, one in which a cartridge filled with a metal catalyst such as Pt or Pd is housed in a container. In the hydrogen treatment device 17, when the gaseous waste flows in the container, hydrogen gas and oxygen gas of the gaseous waste react with each other by the action of the metal catalyst to generate water vapor. The hydrogen treatment device 17 is provided on the upstream side of the storage tank 4, for example, on the extraction line 21. Further, the hydrogen treatment device 17 can be provided on the downstream side of the storage tank 4, for example, on the exhaust pipe line 24, as shown by the chain double-dashed line. However, disposing the hydrogen treatment device 17 on the upstream side of the storage tank 4 can reduce the treatment flow rate of the permeable membrane of the filter module 3.

In this modified example, in addition to diluting the gaseous waste with water vapor, the hydrogen gas in the gaseous waste is generated by reacting the hydrogen gas of the gaseous waste with the oxygen gas by the hydrogen treatment device 17 to generate water vapor. Concentration is further reduced. As a result, the possibility of hydrogen combustion occurring can be further reduced.

In this modification, the number of components of the gas waste treatment facility 1A increases as the hydrogen treatment device 17 is added. However, the hydrogen treatment device 17 is a container-like structure that is slightly larger than the pipeline, and is much smaller than the rare gas holdup device. In addition, there is no equipment necessary for adding the hydrogen treatment device 17. Therefore, the configuration of the gas waste treatment facility 1A does not become complicated and large.

According to the modified example of the first embodiment of the gas waste treatment facility of the present invention described above, as in the first embodiment, the gas waste treatment facility 1A is maintained while maintaining the function of treating the radioactive noble gas. The configuration can be simplified and downsized.

[Second Embodiment]
Next, a second embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIG. FIG. 4 is a system diagram showing the configuration of the second embodiment of the gaseous waste treatment facility of the present invention. Note that, in FIG. 4, the same reference numerals as those shown in FIGS. 1 to 3 denote the same parts, and thus detailed description thereof will be omitted.

The main difference between the second embodiment of the gas waste treatment facility of the present invention shown in FIG. 4 and the first embodiment is that the main route 2B of the gas waste treatment facility 1B does not branch 1 It consists of two routes. Therefore, in the gas waste treatment facility 1B, the number of the filter module 3, the storage tank 4, the radiation detector 13, the pressure detector 14, the bypass path 6, the opening/closing valve 7, and the check valve 15 is one each. .. In addition, in the second embodiment, the switching valve 12 (see FIG. 1) that switches the plurality of branch paths 2a of the main path 2 in the first embodiment is unnecessary.

Specifically, the main path 2B is composed of an extraction line 21, a storage tank 4, an exhaust line 24, and an exhaust tower 25 in order from the upstream side. The extraction line 21 is a line connected to the condenser 103 and the storage tank 4. The storage tank 4 constitutes a part of the main path 2B on the upstream side of the filter module 3. The exhaust pipe line 24 is provided with the filter module 3 at its upstream end, and is connected to the storage tank 4 on the upstream side so that the filter module 3 is arranged in the storage tank 4. The exhaust pipe line 24 is a pipe line that guides the gas that has permeated the permeable membrane of the filter module 3 to the exhaust tower 25. In the bypass route 6 according to the present embodiment, the upstream side is connected to the storage tank 4 (a part of the main route 2B on the upstream side of the filter module 3) and the downstream side is the exhaust pipe line 24 (the main route 2B filter module 3). Is a pipe line connected to the downstream side).

Leakage of radioactive noble gas from a fuel cladding tube is extremely rare due to recent advances in materials. Therefore, in the present embodiment, in the case of the first embodiment including a plurality of storage tanks 4 by increasing the volume of the storage tank 4 even if only one storage tank 4 is provided. Similarly, it is possible to temporarily hold the radioactive noble gas below the withstand pressure of the storage tank 4.

According to the third embodiment of the gaseous waste treatment facility of the present invention described above, a configuration in which the number of main paths for treating gaseous waste is reduced as compared with the first embodiment, that is, a filter module. The number of the storage tank 4, the radiation detector 13, the radiation detector 13, the pressure detector 14, the bypass path 6, the on-off valve 7, the check valve 15 and the switching valve 12 is reduced, so that the processing function of the radioactive noble gas is maintained. It is possible to further simplify and downsize the configuration of the gas waste treatment facility 1B. Therefore, the cost of the gas waste treatment facility 1B can be further reduced.

[Third Embodiment]
Next, a third embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIG. FIG. 5 is a system diagram showing the configuration of the third embodiment of the gaseous waste treatment facility of the present invention. Note that, in FIG. 5, the same reference numerals as those shown in FIGS. 1 to 4 denote the same parts, and thus detailed description thereof will be omitted.

The main difference between the third embodiment of the gaseous waste treatment facility of the present invention shown in FIG. 5 and the first embodiment is that the main route 2C is configured by one route without branching. On the other hand, the bypass path 6C is configured to be branched into a plurality of paths in the middle, the plurality of storage tanks 4C are provided not in the main path 2C but in the plurality of bypass paths 6C, and the filter module 3C is arranged outside the storage tank 4C.

Specifically, the main path 2C of the gas waste treatment facility 1C is composed of an extraction line 21, an exhaust line 24, and an exhaust tower 25 in order from the upstream side. The filter module 3 is provided at the downstream end of the extraction line 21 or the upstream end of the exhaust line 24. The extraction line 21 is provided with a radiation detector 18 that detects the radiation dose of the gas flowing through the extraction line 21.

The bypass path 6C of the gas waste treatment facility 1C has a plurality of (two in FIG. 5) bypass branch paths 6Ca. An on-off valve 7 is provided on each bypass branch path 6Ca. A storage tank 4C is provided at a position upstream of the on-off valve 7 in each bypass branch path 6Ca. Each storage tank 4C constitutes a part of the bypass branch path 6Ca on the upstream side of the on-off valve 7. The bypass path 6C includes, in order from the upstream side, a bypass main pipeline 61, a plurality (two in FIG. 5) of bypass first branch pipelines 62, a plurality (two in FIG. 5) of storage tanks 4C, and a plurality of (FIG. 5 of the two bypass second branch pipe lines 63.

The bypass main pipeline 61 is a pipeline whose upstream side is connected to the extraction pipeline 21 and whose downstream side is connected to the plurality of bypass first branch pipelines 62. The bypass first branch pipeline 62 is a pipeline branched from the bypass main pipeline 61 and connected to the storage tank 4C. The bypass second branch pipeline 63 is a pipeline whose upstream side is connected to the storage tank 4C and whose downstream side is connected to the exhaust pipeline 24.

The bypass main pipe line 61 is provided with a bypass pump 19 that sends a gas that cannot pass through the permeable membrane of the filter module 3C to the storage tank 4C. The bypass path 6C is provided with a bypass switching valve 8 that switches so that any one of the plurality of bypass branch paths 6Ca communicates. The bypass switching valve 8 is, for example, a three-way valve provided at a branch portion of the plurality of bypass first branch pipelines 62. The check valve 15 is provided on the upstream side of the connection portion of the exhaust pipe line 24 with the plurality of bypass second branch pipe lines 63.

Next, a method for treating gaseous waste in the third embodiment of the gaseous waste treatment facility of the present invention will be described. In the gaseous waste treatment facility 1C according to the present embodiment, the bypass pump 19 is normally stopped. Further, the plurality of open/close valves 7 are all closed.

When the radioactive noble gas is confined in the fuel cladding tube, the gaseous waste staying in the condenser 103 (see FIG. 1) flows through the extraction line 21 of the main path 2C by the main pump 11 together with the steam. Through the filter module 3C. The water vapor and hydrogen gas of the gaseous waste introduced to the filter module 3C pass through the permeable membrane of the filter module 3C and are discharged from the exhaust tower 25 to the external environment of the nuclear power plant through the exhaust pipe line 24 and diffused.

On the other hand, if the radioactive noble gas of xenon gas and krypton gas leaks outside the fuel cladding tube, the radioactive noble gas of xenon gas and krypton gas is contained in the gas waste taken into the extraction line 21. The radiation detector 18 provided in the extraction line 21 detects an increase in ambient dose. When the radiation detector 18 detects an increase in the dose, the drive of the bypass pump 19 is started. Further, the bypass switching valve 8 is in a state in which any one of the plurality of (two in FIG. 5) bypass branch paths 6Ca is in communication. For example, as shown in FIG. 5, the bypass first branch conduit 62 of the right bypass branch path 6Ca communicates with the bypass main conduit 61. That is, the main path 2C and the right side storage tank 4C are in communication with each other.

As described above, the hydrogen gas in the gas waste flowing through the extraction line 21 passes through the permeable membrane of the filter module 3C together with the water vapor and is discharged to the external environment of the nuclear power plant. On the other hand, the radioactive noble gases of the xenon gas and the krypton gas in the gaseous waste cannot pass through the permeable membrane of the filter module 3C and stay in the bleed pipe 21 immediately upstream of the filter module 3C. The radioactive noble gas staying in the extraction line 21 is discharged by the bypass pump 19 to the right side through the bypass main pipe line 61 of the bypass line 6C and the right bypass first branch pipe line 62 selected by the bypass switching valve 8. Transferred to the storage tank 4C. The transferred radioactive noble gas remains in the storage tank 4C because all the on-off valves 7 are closed. Therefore, the radioactive noble gas is not discharged to the external environment via the bypass route 6C. As described above, the radioactive noble gas is not contained in the gas discharged to the external environment, so that the external environment is not affected by the radioactivity.

The radioactive noble gas transferred to the storage tank 4C is temporarily held in the storage tank 4C until the radioactivity thereof is attenuated to a predetermined level. When the detection value of the radiation detector 13 of the storage tank 4C is monitored and becomes lower than a predetermined value, the opening/closing valve 7 of the bypass branch path 6Ca on the storage tank 4C side holding the radioactive noble gas is opened. As a result, the radioactive noble gas held in the storage tank 4C is discharged from the exhaust tower 25 to the external environment of the nuclear power plant via the bypass second branch pipeline 63 of the bypass pathway 6C and the exhaust pipeline 24 of the main pathway 2C. Being spread. In this case, since the radioactivity of the radioactive noble gas has already dropped to a safe level, the radioactivity will not affect the external environment.

When the radioactive noble gas continuously leaks to the outside of the fuel cladding tube, the radioactive noble gas that cannot pass through the permeable membrane of the filter module 3C is gradually accumulated in the storage tank 4C on the bypass path 6C, and the inside of the storage tank 4C. The pressure of the radioactive noble gas is increased. When the pressure detection value detected by the pressure detector 14 provided in the storage tank 4C exceeds a predetermined value, another storage tank 4C different from the storage tank 4C holding the radioactive rare gas (in FIG. The bypass switching valve 8 is switched so that the radioactive noble gas is transferred to the storage tank 4C). In the left side storage tank 4C on the bypass branch path 6Ca selected by the bypass switching valve 8, as in the case of the right side storage tank 4C, since the radioactive noble gas that cannot pass through the permeable membrane remains, the radioactive noble gas is bypassed. It is not discharged to the external environment via the route 6C.

At this time, in the right side storage tank 4C holding the radioactive noble gas, the radioactive noble gas does not flow in due to the switching of the bypass switching valve 8, and the pressure does not rise any more. Further, by continuously maintaining the switched state of the bypass branch route 6Ca for a predetermined time or longer, the radioactivity of the radioactive noble gas held in the right storage tank 4C is attenuated. As described above, after the detection value of the radiation detector 13 becomes lower than the predetermined value, the opening/closing valve 7 on the right side is opened and the gas containing the radioactive noble gas held in the storage tank 4C on the right side is bypassed on the right side. It is discharged to the external environment via the branch route 6Ca. As a result, in the storage tank 4C on the right side, the pressure is lowered and the radioactive rare gas can be transferred again.

In the left side storage tank 4C to which the radioactive noble gas is transferred, as in the case of the right side storage tank 4C, the radioactive noble gas that cannot pass through the permeable membrane of the filter module 3C is gradually accumulated and the pressure rises. When the pressure detection value of the left storage tank 4C exceeds a predetermined value, the radioactive noble gas is transferred to another storage tank 4C (right storage tank 4C in FIG. 5) different from the currently selected storage tank 4C. The bypass switching valve 8 is switched as described above. The subsequent steps are the same as the steps described above.

In the present embodiment, since the plurality of storage tanks 4C on the bypass path 6C are arranged in parallel, the permeable membrane of the filter module 3 provided on the main path 2C processes the gas waste, while the permeable membrane is treated. It is possible to reduce the radioactivity below a predetermined level by transferring a radioactive noble gas that cannot pass through to the storage tank 4C of the plurality of storage tanks 4C on the bypass path 6C and temporarily holding it. It is possible. Therefore, the gas waste can be continuously discharged to the external environment while the radioactivity of the radioactive noble gas is attenuated by the plurality of storage tanks 4C, and thus the gas waste treatment facility 1C can be continuously operated.

Further, in the present embodiment, only the radioactive noble gas that may be contained in the gas waste is efficiently separated from the gas waste by the permeable membrane and temporarily retained in the storage tank 4C on the bypass route 6C. While the radioactivity is attenuated, the non-radioactive water vapor or hydrogen gas is positively discharged to the external environment without being retained in the storage tank 4C. Therefore, the storage tank 4C has only the gas that cannot pass through the permeable membrane. Can be taken into consideration. Therefore, the storage tank 4C can be significantly downsized as compared with the existing rare gas holdup device.

Further, in the present embodiment, since the radioactive noble gas is stored in the storage tank 4C while being pressurized by the bypass pump 19, the volume of the radioactive noble gas is reduced accordingly. Therefore, the storage tank 4C can be further downsized.

According to the third embodiment of the gas waste treatment facility of the present invention described above, similarly to the first embodiment, the configuration of the gas waste treatment facility 1C is maintained while maintaining the processing function of radioactive noble gas. It is possible to achieve simplification and miniaturization.

Further, according to the present embodiment, since the main route 2C is configured by one route, only one filter module 3C needs to be provided on the main route 2C, and accordingly, the configuration of the gas waste treatment facility 1C is simple. Can be promoted.

Further, according to the present embodiment, the filter module 3C is arranged outside the storage tank 4C by providing the storage tank 4C not on the main path 2C but on the bypass path 6C. Therefore, it is not necessary to take out the filter module 3C from the storage tank 4C at the time of maintenance, and accordingly, the maintenance of the filter module 3C becomes easy.

[Fourth Embodiment]
Next, a fourth embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIG. FIG. 6 is a system diagram showing the configuration of the fourth embodiment of the gaseous waste treatment facility of the present invention. Note that, in FIG. 6, the same reference numerals as those shown in FIGS. 1 to 5 denote the same parts, and thus detailed description thereof will be omitted.

The main difference between the fourth embodiment of the gas waste treatment facility of the present invention shown in FIG. 6 and the third embodiment is that the bypass route 6D of the gas waste treatment facility 1D does not branch to 1 It consists of two routes. Therefore, in the gas waste treatment facility 1D, the number of the storage tanks 4C, the radiation detectors 13, the pressure detectors 14, and the opening/closing valves 7 is one each. Moreover, in the fourth embodiment, the bypass switching valve 8 (see FIG. 5) that switches the plurality of bypass branch paths 6Ca of the bypass path 6C in the third embodiment is not necessary.

Leakage of radioactive noble gas from a fuel cladding tube is extremely rare due to recent advances in materials. Therefore, in the present embodiment, even if the configuration is provided with only one storage tank 4C, by increasing the volume of the storage tank 4C, in the case of the third embodiment with a plurality of storage tanks 4C. Similarly, it is possible to temporarily hold the radioactive noble gas below the pressure resistance of the storage tank 4C.

According to the fourth embodiment of the gas waste treatment facility of the present invention described above, the number of bypass paths for transferring the radioactive noble gas is reduced as compared to the third embodiment, that is, the storage tank. 4C, the radiation detector 13, the pressure detector 14, the number of on-off valves 7 and the bypass switching valve 8 are reduced, so that the configuration of the gas waste treatment facility 1D is further simplified while maintaining the function of treating radioactive noble gas. It is possible to reduce the size and size. Therefore, the cost of the gas waste treatment facility 1D can be further reduced.

[Fifth Embodiment]
Next, a fifth embodiment of the gaseous waste treatment facility of the present invention will be described with reference to FIG. FIG. 7 is a system diagram showing the configuration of the fifth embodiment of the gaseous waste treatment facility of the present invention. Note that, in FIG. 7, the same reference numerals as those shown in FIGS. 1 to 6 denote the same parts, and thus detailed description thereof will be omitted.

The fifth embodiment of the gaseous waste treatment facility of the present invention shown in FIG. 7 is different from the fourth embodiment in that the storage tank 4C is deleted and the storage tank 4C is deleted. The radiation detector 13, the pressure detector 14, and the bypass pump 19 are deleted. Due to recent advances in materials, the leakage of radioactive noble gas from the fuel cladding tube is extremely rare. Therefore, in the gas waste treatment facility 1E, the entire bypass path 6E is used as a substitute for the storage tank 4C of the fourth embodiment by allowing the conduits forming the bypass path 6E to have a sufficient volume.

In the present embodiment, in the event that the radioactive noble gas leaks out of the fuel cladding tube, hydrogen gas in the gas waste flowing through the extraction line 21 permeates the permeable membrane of the filter module 3C together with water vapor to pass through the nuclear power plant. On the other hand, the radioactive noble gas cannot pass through the permeable membrane of the filter module 3C while being discharged to the outside environment of the filter module 3C, and stays in the pipe lines forming the extraction pipe line 21 and the bypass line 6E immediately upstream of the filter module 3C. In this case, since the open/close valve 7 of the bypass path 6E is in the closed state, the radioactive noble gas is not discharged to the external environment.

The radioactive noble gas staying in the extraction line 21 and the bypass route 6E is temporarily held there until its radioactivity is attenuated to a predetermined level. When the detection value of the radiation detector 18 falls below a predetermined value, the opening/closing valve 7 of the bypass path 6E is opened. As a result, the radioactive noble gas in the extraction pipe line 21 and the bypass route 6E is discharged from the bypass route 6E to the external environment of the nuclear power plant through the exhaust pipe line 24 of the main route 2C from the exhaust tower 25. In this case, since the radioactivity of the radioactive noble gas has already dropped to a safe level, the radioactivity will not affect the external environment.

According to the fifth embodiment of the gas waste treatment facility of the present invention described above, as compared with the fourth embodiment, the storage tank 4C, the radiation detector 13, the pressure detector 14, and the bypass pump 19 are provided. Since the configuration is reduced, it is possible to further simplify the configuration of the gas waste treatment facility 1E while maintaining the function of treating the radioactive noble gas. Therefore, the cost of the gas waste treatment facility 1E can be further reduced.

[Other Embodiments]
The present invention is not limited to the above-described first to fifth embodiments, and various modifications are included. The above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. For example, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of one embodiment can be added to the configuration of another embodiment. Further, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

For example, in the above-described first to fifth embodiments of the gaseous waste treatment facility of the present invention, an example in which a molecular sieving membrane is used as the permeable membrane of the filter module 3 has been shown. However, it is also possible to use a metal-ceramic mixed film or a dense film as the transmission film of the filter module 3. The permeation of a metal-ceramic mixed film or a dense film is basically the adsorption of a specific gas to the surface of the film, the diffusion of the gas adsorbed by the film within the film, and the desorption of the diffused gas from the back surface of the film. It is achieved by going through two stages.

In addition, in the first to fifth embodiments of the above-described gaseous waste treatment equipment of the present invention, in order to take in the gaseous waste and the steam accumulated in the condenser 103 into the main paths 2, 2B, 2C. , An example of the configuration including the main pump 11 is shown. However, instead of the main pump 11, a device that can extract gas waste and steam from the condenser 103 such as a steam injector can be used.

Further, in the above-described first to fifth embodiments of the gaseous waste treatment facility of the present invention, an example in which the present invention is applied to a nuclear power plant having one nuclear reactor 101 is shown. However, the present invention can also be applied to a nuclear power plant including a plurality of nuclear reactors 101. That is, the gaseous waste treatment facility 1F of the present embodiment is shared by a plurality of (two in FIG. 8) nuclear reactors 101, as shown in FIG. The difference between the present embodiment and the first embodiment is that the configuration between the condenser 103 and the storage tank 4 in the main passage 2F has a number of passages according to the number of condensers 103. That is. Specifically, the main path 2F has a plurality of (two in FIG. 8) extraction pipes connected to each condenser 103 and a plurality (4 in FIG. 8) connected to each extraction pipe 21. ) Of the first branch conduit 22 of FIG. The main pump 11 is provided in each extraction pipe 21. That is, the gas waste treatment facility 1F takes in the gas wastes generated in the plurality of nuclear reactors 101 from the plurality of condensers 103 via the main path 2F, processes them in the filter module 3, and then releases them to the external environment. Is configured. As described above, since the gas waste treatment facility 1F of the present embodiment is shared by a plurality of (two in FIG. 8) reactors 101, the gas waste treatment facility for each reactor 101 is respectively. The configuration is simpler than when installing.

1, 1A, 1B, 1C, 1D, 1E, 1F... Gas waste treatment facility, 2, 2B, 2C, 2F... Main path, 2a... Branch path, 3, 3C... Filter module (permeable membrane), 4, 4C ... Storage tank, 6, 6C, 6D, 6E... Bypass path, 6Ca... Bypass branch path, 7... Open/close valve, 8... Bypass switching valve, 11... Main pump, 12... Switching valve, 17... Hydrogen treatment device, 19... Bypass pump, 101... Reactor

Claims (15)

A main path configured to take in gas containing gaseous waste produced in a nuclear power plant reactor and to direct it to the external environment of said nuclear power plant;
A permeable membrane that is provided on the main path and has a property that water vapor and hydrogen gas are easily transmitted while xenon gas and krypton gas are difficult to be transmitted,
One end side is connected to a portion of the main path on the upstream side of the permeable membrane and the other end side is connected to a portion of the main path on the downstream side of the permeable membrane, and gas that cannot pass through the permeable membrane is permeated. A bypass path capable of flowing around the membrane,
A gas waste treatment facility, comprising: an opening/closing valve that is provided on the bypass path and that opens and closes the bypass path. The gaseous waste treatment facility according to claim 1,
A gas waste treatment facility, wherein the permeable membrane is a molecular sieving membrane that selectively permeates a specific gas by utilizing the difference in molecular diameter of the gas. The gaseous waste treatment facility according to claim 2,
The gas waste treatment facility, wherein the molecular sieve film is a ceramic film containing silicon nitride as a main component. The gaseous waste treatment facility according to claim 2,
The gas waste treatment facility, wherein the molecular sieving film is a polymer film containing polyimide as a main component. The gaseous waste treatment facility according to claim 2,
The gas waste treatment facility, wherein the molecular sieving film is a graphene oxide film containing carbon as a main component. The gaseous waste treatment facility according to claim 1,
The gas waste treatment facility further comprising a storage tank capable of temporarily holding a gas that cannot pass through the permeable membrane. The gaseous waste treatment facility according to claim 6,
The storage tank is provided on the main path in a state where the permeable membrane is arranged inside, and constitutes a part of the main path on an upstream side of the permeable membrane,
The bypass passage has one end connected to the storage tank. The gaseous waste treatment facility according to claim 7,
The main route has a plurality of branch routes,
The storage tank is provided on each of the plurality of branch paths,
The gas waste treatment facility, wherein the main route is configured to be switched so that any one of the plurality of branch routes communicates with each other. The gaseous waste treatment facility according to claim 6,
The storage tank is provided in a portion on the upstream side of the on-off valve on the bypass path,
The gas waste treatment facility further comprising a bypass pump which is provided on the bypass path and transfers a gas that cannot pass through the permeable membrane to the storage tank. The gaseous waste treatment facility according to claim 9,
The bypass path has a plurality of bypass branch paths,
The on-off valve is provided on each of the plurality of bypass branch paths,
The storage tank is provided on each of the plurality of bypass branch paths,
The gas waste treatment facility is configured such that the bypass path is switched so that any one of the plurality of bypass branch paths is in communication. The gaseous waste treatment facility according to claim 1,
A gaseous waste treatment facility further comprising a hydrogen treatment device which is provided on the main route and which generates steam from hydrogen gas and oxygen gas among the gaseous wastes flowing through the main route. The gaseous waste treatment facility according to claim 1,
The said main path|route is comprised so that the gaseous waste produced|generated by several nuclear reactors may be taken in. The gaseous waste treatment facility characterized by the above-mentioned. A gas containing gaseous waste generated in a nuclear reactor of a nuclear power plant is led to a permeable membrane having characteristics that water vapor and hydrogen gas are easily permeated while xenon gas and krypton gas are difficult to permeate,
The gas that has permeated the permeable membrane is discharged to the external environment of the nuclear plant,
A gas waste treatment method comprising: temporarily holding a gas that cannot pass through the permeable membrane and then releasing the gas to the external environment of the nuclear power plant via a bypass path that bypasses the permeable membrane. The gaseous waste treatment method according to claim 13,
Temporarily holding a gas that cannot pass through the permeable membrane in at least one storage tank,
A method for treating gaseous waste, comprising discharging the gas in the storage tank to the external environment of the nuclear power plant after the radioactivity of the gas in the storage tank has dropped below a predetermined level. The method for treating gaseous waste according to claim 14,
A plurality of the storage tanks are arranged in parallel,
Holding a gas that cannot pass through the permeable membrane in any one of the storage tanks,
When the pressure in the storage tank holding the gas that cannot pass through the permeable membrane exceeds a predetermined pressure value, another storage tank different from the storage tank holding the gas that cannot pass through the permeable membrane is used. A gas waste treatment method, wherein switching is performed so that a gas that cannot pass through the permeable membrane is introduced into the storage tank.

Images