JP6377019B2 - Radioactive gas removal device - Google Patents

Description

  The present invention relates to a radioactive gas removal apparatus that removes radioactive gas.

  Conventionally, in Patent Document 1, for example, when iodine in a processing target gas is adsorbed by an iodine adsorbent, the processing target gas is heated by a heating device and the first temperature of the processing target gas flowing into the heating device is set. It is shown that the second temperature of the gas to be processed flowing into the iodine adsorbent is measured and the heating device is controlled so that the second temperature becomes a value obtained by adding a predetermined temperature to the first temperature. .

  Conventionally, for example, in Patent Document 2, a radioactive gas filter that adsorbs radioactive iodine, radioactive methyl iodide, and radioactive substances contained in a gas in a casing, and an upstream side of gas flow from the radioactive gas filter. A heating unit that heats the gas that is circulated through the casing, an upstream thermometer that measures the temperature of the gas that is provided upstream of the gas flow and reaches the heating unit, and a heating unit A downstream thermometer that measures the temperature of the gas that reaches the radioactive gas filter on the downstream side of the gas flow upstream of the radioactive gas filter and the gas measured by the upstream thermometer. It is shown that the control part which controls a heating part based on the temperature of the gas measured with a downstream thermometer with temperature is provided.

JP2013-156168A JP 2014-35286 A

  Patent Document 1 has the following description. “Iodine adsorbents used in the past are easily affected by temperature and humidity in the exhaust gas, especially humidity. When the humidity in the exhaust gas is high, the iodine removal performance of the iodine adsorbent decreases. In addition, it was not possible to remove radioactive iodine stably with high efficiency, and the influence of temperature and humidity on iodine removal performance of iodine adsorbents was not clear, and the temperature was 30 ° C and the relative humidity was 93%. Considering the actual environmental conditions of RH to 96% RH, it was a strict inspection condition of relatively low temperature and high humidity. "

  And the invention of patent document 1, 2 mentioned above raises the temperature of the gas distribute | circulated to the filter which adsorb | sucks iodine, and makes the relative humidity of gas low and improves the performance of a filter.

  However, in an atmosphere where the temperature of the atmosphere (outside air) is lower than that described above and in a high humidity, immediately after starting the apparatus, the gas temperature is still low and the relative humidity remains high. Low, radioactive iodine and radioactive methyl iodide contained in the gas that has passed through this filter, and radioactive substances may affect the human body.

  This invention solves the subject mentioned above, and it aims at providing the radioactive gas removal apparatus which can be used in the state by which the removal performance of radioactive gas was ensured.

  In order to achieve the above-described object, the radioactive gas removal device of the present invention includes a flow passage forming a series of passages through which gas can flow, a blower for flowing gas from one end of the flow passage to the other end, and the flow A heating unit that heats a gas in the passage; a radioactive gas filter that removes a radioactive substance contained in the gas in the flow path downstream of the heating unit; and a downstream side of the radioactive gas filter that is the flow path A switching portion that is provided at a position before the other end of the gas passage and opens and closes the other end side of the flow passage while opening and closing the flow passage with respect to the outside, and a temperature detecting gas temperature outside the flow passage. One temperature detection unit, a second temperature detection unit for detecting the temperature of the gas in the flow path and downstream of the radioactive gas filter, and the other end side of the flow path closed with the operation of the blower And open the flow passage to the outside. The heating unit is operated when the switching unit is controlled and the temperature detected by the first temperature detection unit is equal to or lower than a preset temperature, and then the temperature detected by the second temperature detection unit is the first temperature A control unit that controls the switching unit by opening the other end of the flow passage and closing the flow passage to the outside when a predetermined temperature higher than the temperature of the temperature detection unit is reached. It is characterized by.

  According to this radioactive gas removing device, when the outside air temperature is lower than the set temperature, the gas is stopped from being discharged from one end of the flow passage until the relative humidity at which the desired element removal efficiency is obtained by the radioactive gas filter. The gas can be discharged from one end of the flow passage when the desired iodine removal efficiency is obtained by the gas filter. As a result, it can be used in a state in which the removal performance of the radioactive gas is ensured.

  The radioactive gas removal device of the present invention further includes a third temperature detection unit that detects the temperature of the gas in the flow path and between the heating unit and the radioactive gas filter, and the control unit includes: If the temperature detected by the third temperature detector does not exceed the temperature detected by the first temperature detector, close the other end of the flow passage and open the flow passage to the outside. The switching unit is controlled.

  According to this radioactive gas removal device, when the outside air temperature is not raised by the heating unit, that is, when the heating unit is not functioning due to a failure or the like, the gas flowing from one end into the flow passage passes through the flow passage. However, it is discharged to the outside from the communication path and is not discharged from the other end. As a result, the performance of the heating unit can be confirmed, and when the performance is not ensured, the discharge of gas from the other end can be stopped.

  Moreover, the radioactive gas removal device of the present invention further includes a communication path that connects a portion of the switching unit that opens and closes the flow path to the outside and an upstream side of the heating unit in the flow path. And

  According to this radioactive gas removal device, the gas flowing into the flow passage from one end is returned to the upstream side of the heating unit and circulated. For this reason, in the case where the heating unit is not operated, the temperature rising effect accompanying the operation of the blower can be increased, and in the case where the heating unit is operated, the temperature rising effect of the heating unit can be increased.

  Moreover, the radioactive gas removal device of the present invention is further characterized by further comprising a heating unit for heating the gas reaching the radioactive gas filter.

  According to this radioactive gas removal apparatus, the gas that reaches the radioactive gas filter is heated by the heating unit. For this reason, the relative humidity of the gas reaching the radioactive gas filter can be reduced.

  In addition, the radioactive gas removal device of the present invention is further characterized by further comprising a heat retaining unit for retaining the temperature of the device.

  According to this radioactive gas removal device, the temperature reaching the radioactive gas filter is kept warm by the heat retaining unit. For this reason, the relative humidity of the gas reaching the radioactive gas filter can be maintained or reduced.

  According to the present invention, it can be used in a state in which the removal performance of radioactive gas is ensured.

FIG. 1 is a configuration diagram of a radioactive gas removal device according to Embodiment 1 of the present invention. FIG. 2 is a configuration diagram of a filter unit in the radioactive gas removal device according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing the relationship between the removal efficiency of radioactive substances in gas at temperature and humidity. FIG. 4 is a diagram showing the relationship between air temperature and humidity when the outside air is heated by 5 ° C. FIG. 5 is a diagram showing the relationship between air temperature and humidity when the outside air is heated by 10 ° C. FIG. 6 is a flowchart showing the operation of the radioactive gas removal device according to Embodiment 1 of the present invention. FIG. 7 is a configuration diagram of a radioactive gas removal device according to Embodiment 2 of the present invention. FIG. 8 is a flowchart showing the operation of the radioactive gas removal device according to Embodiment 2 of the present invention. FIG. 9 is a configuration diagram of a radioactive gas removal device according to Embodiment 3 of the present invention. FIG. 10 is a configuration diagram of a radioactive gas removal device according to Embodiment 4 of the present invention. FIG. 11 is a configuration diagram of a radioactive gas removal device according to Embodiment 5 of the present invention. FIG. 12 is a configuration diagram of a radioactive gas removal device according to Embodiment 6 of the present invention. FIG. 13 is a configuration diagram of a radioactive gas removal device according to Embodiment 7 of the present invention.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

In a nuclear facility such as a nuclear power plant, radioactive gas, particularly simple iodine ( ¹²⁹ I ₂ , ¹³¹ I ₂ , ¹³³ I ₂ ) and methyl iodide (CH ₃ ¹²⁹ I, CH ₃ ¹³¹ ) from the viewpoint of protecting the surrounding environment. It is an important issue to reduce the amount of radioactive iodine released from an organic iodine compound containing I, CH ₃ ¹³³ I) as a main component.

[Embodiment 1]
FIG. 1 is a configuration diagram of a radioactive gas removal device according to the present embodiment. FIG. 2 is a configuration diagram of a filter unit in the radioactive gas removal device according to the present embodiment.

  As shown in FIG. 1, the radioactive gas removal device 1 of the present embodiment includes a flow path 2, a blower 3, a heating unit 4, a radioactive gas filter 5, a switching unit 6, and a first temperature detection unit 7. The second temperature detection unit 8 and the control unit 9 are provided.

  The flow passage 2 is a series of passages through which gas can flow, and is configured such that one end 2a and the other end 2b are opened.

  The blower 3 is provided in the middle of the flow passage 2 and allows gas to flow from one end 2a of the flow passage 2 to the other end 2b.

  The heating unit 4 is provided in the flow passage 2 and heats the gas in the flow passage 2. The heating unit 4 is configured by, for example, an electric heater. The heating unit 4 is provided on the one end 2 a side which is the upstream side of the gas in the flow passage 2.

  The radioactive gas filter 5 is provided in the flow path 2 and downstream of the gas from the heating unit 4. The radioactive gas filter 5 adsorbs radioactive iodine and radioactive methyl iodide contained in the gas flowing through the flow passage 2. Specifically, the radioactive gas filter 5 includes a base material constituting the base body and an attachment material attached to the base material. The material used for the substrate is not particularly limited as long as it has a plurality of pores on the surface, and examples thereof include activated carbon, alumina, zeolite, silica gel, and activated clay. The zeolite may be either natural zeolite or synthetic zeolite. Examples of zeolite include mordenite zeolite. A base material can be used individually or in combination of 2 types or more, respectively. Moreover, the radioactive gas filter 5 contains a triethylenediamine (TEDA: Tri-Ethylene-Di-Amine) or potassium iodide (KI) as an attachment substance. The radioactive gas filter 5 adsorbs radioactive iodine and radioactive methyl iodide with the above-described configuration.

  In the present embodiment, the radioactive gas filter 5 is included in the filter unit. As shown in FIG. 2, the filter portion has a casing 5A that is formed in a cylindrical shape or the like (including a quadrangular shape) surrounded by an outer wall and that has one end 5Aa and the other end 5Ab open. The casing 5A is provided in the middle of the flow passage 2 with one end 5Aa on the upstream side of the gas and the other end 5Ab on the downstream side of the gas. The filter unit is provided with a coarse filter 5B, an upstream high-performance filter 5C, a radioactive gas filter 5, and a downstream high-performance filter 5D from the one end 5Aa side in the casing 5A. As the coarse filter 5B, for example, an air filtration filter having a target particle diameter of 50 μm or more, or a medium / high performance filter having a target particle diameter of 25 μm or more is applied. As the upstream high-performance filter 5C and the downstream high-performance filter 5D, for example, an HEPA filter (High Efficiency Particulate Air Filter) with a target particle diameter of 0.15 μm and a removal efficiency of 99.97% is applied. The radioactive gas filter 5 may be disposed in a plurality of layers in the gas flow direction.

  The switching unit 6 shown in FIG. 1 is provided at a site downstream of the radioactive gas filter 5 (filter unit) and in front of the other end 2 b of the flow passage 2. The switching unit 6 opens and closes the flow path 2 to the outside while opening and closing the other end 2 b side of the flow path 2. Specifically, the switching unit 6 includes a first on-off valve 6A provided on the other end 2b side of the flow passage 2 and a second on-off valve provided on the communication passage 6Ba communicating from the flow passage 2 to the outside. 6B. That is, the other end 2b side of the flow passage 2 is opened and closed by the opening / closing operation of the first opening / closing valve 6A. Further, the flow passage 2 is opened and closed with respect to the outside by the opening / closing operation of the second opening / closing valve 6B.

  The first temperature detector 7 detects the temperature of the gas outside the flow passage 2. In the present embodiment, the first temperature detection unit 7 detects the outside air temperature outside the flow passage 2. Note that the outside air temperature is the ambient temperature where the radioactive gas removal device 1 is disposed, and is the atmospheric temperature when the radioactive gas removal device 1 is disposed outdoors, and the radioactive gas removal device 1 is disposed indoors. If it is, it is indoor air temperature. The first temperature detection unit 7 may be installed in the flow path 2a on the upstream side of the heating unit 4.

  The second temperature detector 8 detects the temperature of the gas in the flow path 2 and downstream of the radioactive gas filter 5. That is, the second temperature detection unit 8 is disposed immediately after the radioactive gas filter 5 in the gas flow direction.

  The control unit 9 controls the blower 3, the heating unit 4, and the switching unit 6 based on the gas temperatures detected by the first temperature detection unit 7 and the second temperature detection unit 8. Specifically, the control unit 9 controls the switching unit 6 based on the relationship between the removal efficiency of radioactive substances in the gas depending on the gas temperature and humidity.

  Here, FIG. 3 is a diagram showing the relationship between the removal efficiency of radioactive substances in the gas at temperature and humidity. FIG. 4 is a diagram showing the relationship between air (gas) temperature and humidity when the outside air is heated by 5 ° C. FIG. 5 is a diagram showing the relationship between air temperature and humidity when the outside air is heated by 10 ° C.

  In FIG. 3, A is the iodine removal efficiency of the iodine adsorbent at each temperature condition at a relative humidity of 95% RH, and B is the iodine removal of the iodine adsorbent at each temperature condition at a relative humidity of 90% RH. C is the iodine removal efficiency of the iodine adsorbent at each temperature condition at a relative humidity of 85% RH, and D is the iodine removal efficiency of the iodine adsorbent at each temperature condition at a relative humidity of 80% RH. E is the iodine removal efficiency of the iodine adsorbent under each temperature condition at a relative humidity of 70% RH. A is based on ASTM-D3809 that defines the iodine removal efficiency of the iodine filter. In this regulation, iodine removal efficiency is regulated under inspection conditions of a temperature of 30 ° C. and a relative humidity of 93% RH to 96% RH. That is, if it is in the range above the broken line from the value obtained under the above-described inspection conditions, the removal efficiency is higher than this, so that the element removal efficiency is desirable. It can be seen that even if the temperature is not 30 ° C., the desired element removal efficiency can be obtained if the humidity is lower than the specified range.

  In FIG. 4, F is the relative humidity after the outside air has been heated by 5 ° C. in a state where the relative humidity is 100% RH. When F1 is heated from 0 ° C. to 5 ° C., F2 is from 5 ° C. to 10 ° C. F3 is heated from 10 ° C to 15 ° C, F4 is heated from 15 ° C to 20 ° C, F5 is heated from 20 ° C to 25 ° C, F6 is When F is raised from 25 ° C. to 30 ° C., F7 is raised from 30 ° C. to 35 ° C., and F8 is raised from 35 ° C. to 40 ° C. G is a relative humidity after the outside air is heated by 5 ° C. in a state where the relative humidity is 90% RH. When G1 is heated from 0 ° C. to 5 ° C., G2 is heated from 5 ° C. to 10 ° C. G3 is heated from 10 ° C. to 15 ° C., G4 is heated from 15 ° C. to 20 ° C., G5 is heated from 20 ° C. to 25 ° C., G6 is heated from 25 ° C. When the temperature is raised to 30 ° C., G7 is when the temperature is raised from 30 ° C. to 35 ° C. H is the relative humidity after the outside air is heated by 5 ° C. in the state of relative humidity 80% RH. When H1 is heated from 0 ° C. to 5 ° C., H2 is heated from 5 ° C. to 10 ° C. H3 is heated from 10 ° C to 15 ° C, H4 is heated from 15 ° C to 20 ° C, H5 is heated from 20 ° C to 25 ° C, and H6 is heated from 25 ° C. This is a case where the temperature is raised to 30 ° C. I is the relative humidity after the outside air is heated by 5 ° C. in a state where the relative humidity is 70% RH. When I1 is heated from 0 ° C. to 5 ° C., I2 is heated from 5 ° C. to 10 ° C. When I3 is raised from 10 ° C to 15 ° C, I4 is raised from 15 ° C to 20 ° C, I5 is raised from 20 ° C to 25 ° C, and I6 is raised from 25 ° C. This is a case where the temperature is raised to 30 ° C. The above is an example of the calculation result.

  In FIG. 5, J is the relative humidity after the outside air is heated by 10 ° C. in a state where the relative humidity is 100% RH, and J1 is 5 ° C. to 15 ° C. when J1 is heated from 0 ° C. to 10 ° C. J3 is heated from 10 ° C to 20 ° C, J4 is heated from 15 ° C to 25 ° C, J5 is heated from 20 ° C to 30 ° C, J6 is When the temperature is raised from 25 ° C to 35 ° C, J7 is when the temperature is raised from 30 ° C to 40 ° C, and J8 is when the temperature is raised from 35 ° C to 45 ° C. K is the relative humidity after the outside air is heated by 10 ° C. in a state where the relative humidity is 90% RH. When K1 is heated from 0 ° C. to 10 ° C., K2 is heated from 5 ° C. to 15 ° C. K3 is raised from 10 ° C to 20 ° C, K4 is raised from 15 ° C to 25 ° C, K5 is raised from 20 ° C to 30 ° C, and K6 is raised from 25 ° C. This is a case where the temperature is raised to 35 ° C. L is a relative humidity after the outside air is heated by 10 ° C. in a state where the relative humidity is 80% RH. When L1 is heated from 0 ° C. to 10 ° C., L2 is heated from 5 ° C. to 15 ° C. In this case, L3 is raised from 10 ° C to 20 ° C, L4 is raised from 15 ° C to 25 ° C, and L5 is raised from 20 ° C to 30 ° C. M is a relative humidity after the outside air is heated by 10 ° C. in a state where the relative humidity is 70% RH. When M1 is heated from 0 ° C. to 10 ° C., M2 is heated from 5 ° C. to 15 ° C. In this case, M3 is raised from 10 ° C to 20 ° C, M4 is raised from 15 ° C to 25 ° C, and M5 is raised from 20 ° C to 30 ° C. The above is an example of the calculation result.

  Therefore, as shown in FIG. 4, it can be seen that by raising the temperature by 5 ° C., the relative humidity reaches a range where the element removal efficiency can be obtained as shown in FIG. Further, as shown in FIG. 5, it can be seen that if the temperature is raised by 10 ° C., the relative humidity reaches a sufficient range to obtain the element removal efficiency as shown in FIG. And when the temperature of the original outside air is 5 ° C. or less, it can be seen that the relative humidity reaches a range in which the element removal efficiency can be obtained as desired in FIG. 3 by raising the temperature to 10 ° C.

  Therefore, in the control unit 9, the temperature of the original outside air detected by the first temperature detection unit 7 is set as a set temperature, and if the set temperature is 5 ° C. or less, the heating unit 4 supplies the gas flowing into the flow passage 2. It can be determined to raise the temperature. Then, assuming that the temperature of the gas that has passed through the radioactive gas filter 5 detected by the second temperature detection unit 8 after being heated by the heating unit 4 is a predetermined temperature, the relative humidity is as shown in FIG. Thus, it can be determined that the desired iodine removal efficiency is within a range that can be obtained. The control unit 9 controls the heating unit 4 or the switching unit 6 based on these determinations.

  In the present embodiment, as shown in FIG. 1, the radioactive gas removal apparatus 1 is connected to the room 50 at the other end 2 b of the flow passage 2. The room 50 is surrounded by walls, a ceiling, and a floor. This room 50 is, for example, a control room installed in a reactor building for controlling and monitoring nuclear facilities, a room installed in a reactor building for meetings and residences, an accident in a nuclear facility, etc. An alternate control room installed outside the reactor building to control and monitor nuclear facilities, an alternate room installed outside the reactor building for meetings and residence in the event of a nuclear facility accident, an accident in a nuclear facility There are emergency rooms for evacuating people working near nuclear facilities and residents near nuclear facilities, hospitals and nursing homes near nuclear facilities. In the present embodiment, the room 50 is supplied with the gas that has passed through the radioactive gas removal device 1 and exhausts the internal air from the exhaust part 51. Although not clearly shown in the figure, the room 50 is provided with a changing area for going in and out while minimizing the internal pressure drop and air loss. Moreover, although not shown in the figure, the room 50 is provided with an air conditioning facility for appropriately maintaining the internal temperature and humidity as necessary. Although not shown in the figure, the room 50 includes a pressure adjusting unit that adjusts the pressure inside the room 50 to be higher than the pressure outside the room 50 (atmospheric pressure).

  FIG. 6 is a flowchart showing the operation of the radioactive gas removal device according to the present embodiment. For example, when an accident occurs in a nuclear facility (step S1), evacuation to the room 50 is performed. As preparation, the control unit 9 operates the blower 3 (step S2) and the first of the switching unit 6 The on-off valve 6A is closed to close the other end 2b of the flow passage 2, and the second on-off valve 6B is opened to open the flow passage 2 to the outside (step S3). In this way, the gas flowing from the one end 2 a into the flow passage 2 and passing through the radioactive gas filter 5 passes through the flow passage 2 and is discharged from the communication passage 6 Ba to the outside and reaches the room 50. Absent. Thereafter, the control unit 9 acquires the temperature (outside temperature) detected by the first temperature detection unit 7, and when this temperature is equal to or lower than the set temperature (5 ° C. in the present embodiment) (step S4: Yes), The heating unit 4 is operated (step S5). Thereafter, the control unit 9 acquires the temperature detected by the second temperature detection unit 8 (the filter temperature that has passed through the radioactive gas filter 5), and this temperature is equal to or higher than a predetermined temperature (10 ° C. in the present embodiment). (Step S6: Yes), the first opening / closing valve 6A of the switching unit 6 is opened to open the other end 2b of the flow passage 2, the second opening / closing valve 6B is closed, and the flow passage 2 is closed to the outside (step). S7) This control is terminated. By doing in this way, the gas which flows through the flow path 2 from the one end 2a and reaches the set temperature or higher and passes through the radioactive gas filter 5 passes through the flow path 2 and is supplied to the room 50. When the temperature is lower than the predetermined temperature in step S6 (step S6; No), the filter temperature is monitored until the temperature becomes equal to or higher than the predetermined temperature. If the set temperature is exceeded in step S4 (step S4: No), the first opening / closing valve 6A of the switching unit 6 is opened, the other end 2b of the flow passage 2 is opened, and the second opening / closing valve 6B is closed. The flow path 2 is closed with respect to the outside (step S7).

  As described above, when the outside air temperature is equal to or lower than the set temperature, the radioactive gas removal apparatus 1 of the present embodiment supplies gas to the room 50 until the relative humidity at which the element removal efficiency is obtained by the radioactive gas filter 5 is obtained. And the gas within the range in which the desired element removal efficiency can be obtained by the radioactive gas filter 5 can be supplied to the room 50. As a result, it can be used in a state in which the removal performance of the radioactive gas is ensured.

  In addition, the humidity can be directly detected by arranging a humidity detector (not shown) together with the second temperature detector 8 or by using the second temperature detector 8 as a thermohygrometer. By detecting the humidity, the control unit 9 can determine that the relative humidity is suitable.

  If the discharge pressure of the blower 3 is about 5 kPa, a temperature rise of 5 ° C. or more can be expected as the blower 3 is operated. When the part 4 is an electric heater, power consumption can be reduced.

  In addition, although the air blower 3 is provided between the heating part 4 and the radioactive gas filter 5 in FIG. 1, it is located upstream of the gas from the heating part 4 or between the radioactive gas filter 5 and the switching part 6. It may be provided.

[Embodiment 2]
FIG. 7 is a configuration diagram of the radioactive gas removal device according to the present embodiment. FIG. 8 is a flowchart showing the operation of the radioactive gas removal device according to this embodiment.

  The present embodiment is different from the first embodiment described above in that the third temperature detection unit 10 is provided, and the others are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The third temperature detection unit 10 detects the temperature of the gas in the flow path 2 and downstream of the heating unit 4. That is, the third temperature detection unit 10 is disposed immediately after the heating unit 4 in the gas flow direction.

  In the operation in the first embodiment shown in FIG. 6, when the control unit 9 operates the heating unit 4 (step S <b> 5), the control unit 9 acquires the temperature (outside air temperature) detected by the first temperature detection unit 7, When the temperature detected by the third temperature detection unit 10 (the heating unit downstream temperature via the heating unit 4) is obtained and the heating unit downstream temperature exceeds the outside air temperature as shown in FIG. 8 (step S11: Yes) ), This control is terminated. On the other hand, in step S11, when the heating unit downstream temperature does not exceed the outside air temperature (step S11: No), the first on-off valve 6A of the switching unit 6 is closed, the other end 2b of the flow passage 2 is closed, and the second The on-off valve 6B is opened to open the flow passage 2 to the outside (step S12), and this control is finished.

  In this way, when the outside air temperature is not raised by the heating unit 4, that is, when the heating unit 4 is not functioning due to a failure or the like, the gas flowing from the one end 2 a into the flow passage 2 is transferred to the flow passage 2. It passes through the inside and is discharged from the communication path 6Ba to the outside and does not reach the room 50. As a result, the performance of the heating unit 4 can be confirmed. Thus, when the performance of the heating unit is not ensured, the supply of gas to the room 50 can be stopped.

[Embodiment 3]
FIG. 9 is a configuration diagram of the radioactive gas removal device according to the present embodiment.

  The present embodiment is different from the above-described first embodiment in the configuration of the communication path 6Ba of the switching unit 6 and is otherwise the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, the present embodiment can be applied to the above-described second embodiment.

  As shown in FIG. 9, one end of the communication path 6Ba is communicated between the downstream side of the radioactive gas filter 5 (filter part) in the flow path 2 and the first on-off valve 6A, and the other end is one end of the flow path 2. The second opening / closing valve 6B is provided in the middle of the 2a side and communicates with the upstream side of the heating unit 4. That is, the communication path 6Ba connects a portion of the switching unit 6 that opens and closes the flow path 2 to the outside and the upstream side of the heating unit 4 in the flow path 2.

  Therefore, according to the radioactive gas removal device 1 of this embodiment, the first on-off valve 6A of the switching unit 6 is closed to close the other end 2b of the flow passage 2, and the second on-off valve 6B is opened to open the flow passage 2. When opened to the outside, the gas in the flow passage 2 that has passed through the radioactive gas filter 5 is returned to the upstream side of the heating unit 4 through the communication passage 6Ba and circulated. For this reason, in the case where the heating unit 4 is not operated, the temperature rising effect accompanying the operation of the blower 3 can be increased, and in the case where the heating unit 4 is operated, the temperature increasing effect of the heating unit 4 is increased. Can do. As a result, when the relative humidity of the gas reaching the radioactive gas filter 5 is increased and the outside air temperature exceeds the set temperature, the temperature rise effect associated with the operation of the blower 3 is enhanced and the iodine removal efficiency by the radioactive gas filter 5 is improved. When the outside air temperature is equal to or lower than the set temperature, the heating effect of the heating unit 4 can be increased and the radioactive gas filter 5 can reach the relative humidity range where the element removal efficiency can be obtained as desired. .

[Embodiment 4]
FIG. 10 is a configuration diagram of the radioactive gas removal device according to the present embodiment.

  The present embodiment is different from the above-described first embodiment in that a heating unit 11 is further provided on the upstream side of the radioactive gas filter 5, and the others are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. In addition, the present embodiment can be applied to the above-described second and third embodiments.

  As shown in FIG. 10, the heating unit 11 is provided on the upstream side of the radioactive gas filter 5 and on the downstream side of the heating unit 4, and heats the gas that reaches the radioactive gas filter 5. The heating unit 11 is configured by an electric heater, for example. Although the heating part 11 may be provided in the flow path 2, it may be provided in the casing 5A of the filter part mentioned above, and upstream of the coarse filter 5B.

  Therefore, according to the radioactive gas removal apparatus 1 of this embodiment, the relative humidity of the gas reaching the radioactive gas filter 5 can be reduced by heating the gas reaching the radioactive gas filter 5 by the heating unit 11. . As a result, when the outside air temperature exceeds the set temperature, iodine removal efficiency by the radioactive gas filter 5 can be improved, and when the outside air temperature is equal to or lower than the set temperature, synergistically with the temperature rising effect of the heating unit 4. The radioactive gas filter 5 can reach the range of relative humidity where the desired iodine removal efficiency can be obtained earlier.

  The heating unit 11 is controlled by the control unit 9, and the operation timing is the same as the operation of the blower 3 or the operation of the heating unit 4. This timing is set as appropriate.

[Embodiment 5]
FIG. 11 is a configuration diagram of the radioactive gas removal device according to the present embodiment.

  The present embodiment is different from the first embodiment described above in that a heat retaining unit 12 is further provided, and the others are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, the present embodiment can be applied to the above-described second to fourth embodiments.

  As shown in FIG. 11, the heat retaining unit 12 is installed so as to cover the outer periphery of the apparatus, and is made of a heat insulating material. In FIG. 11, the heat retaining unit 12 is configured to cover up to a part of the communication path 6 </ b> Ba of the switching unit 6. In addition, when applying to the fourth embodiment described above, the heat retaining unit 12 may be configured to cover the entire communication path 6Ba shown in FIG.

  Therefore, according to the radioactive gas removal apparatus 1 of this embodiment, the relative humidity of the gas reaching the radioactive gas filter 5 can be maintained or reduced by keeping the gas reaching the radioactive gas filter 5 by the heat retaining unit 12. . As a result, when the outside air temperature exceeds the set temperature, iodine removal efficiency by the radioactive gas filter 5 can be maintained or improved, and when the outside air temperature is equal to or lower than the set temperature, it synergizes with the temperature rise effect of the heating unit 4. Thus, the radioactive gas filter 5 can reach the relative humidity range where the desired iodine removal efficiency can be obtained earlier.

[Embodiment 6]
FIG. 12 is a configuration diagram of the radioactive gas removal device according to the present embodiment.

  The present embodiment is different from the first embodiment described above in that a switching unit 15 is provided in place of the switching unit 6 and the others are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, the present embodiment can be applied to the above-described second to fifth embodiments.

  As shown in FIG. 12, the switching part 15 consists of a three-way valve. That is, the switching unit 15 switches the gas that has passed through the radioactive gas filter 5 between a flow path that supplies the room 50 and a flow path that discharges the gas outside the flow path 2 and does not supply the room 50. The gas discharged to the outside of the flow passage 2 is discharged through the communication passage 15 a connected to the switching channel of the switching unit 15. The switching unit 15 is controlled by the control unit 9, and in the operation shown in FIG. 6, the flow is switched to a flow path that does not supply gas to the room 50 in step S <b> 3, and is switched to the flow path that supplies gas to the room 50 in step S <b> 7.

  The communication path 15a corresponds to the communication path 6Ba in the switching unit 6 described above. Therefore, when applied to the third embodiment, the communication passage 15 a is communicated from the switching unit 15 to the one end 2 a side of the flow passage 2 and to the upstream side of the heating unit 4.

[Embodiment 7]
FIG. 13 is a configuration diagram of the radioactive gas removal device according to the present embodiment.

  This embodiment is different from the first embodiment described above in that one end 2a of the flow passage 2 is connected to the local space 100 where radioactive gas can exist and the other end 2b of the flow passage 2 is opened to the atmosphere. Others are the same. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted. Further, the present embodiment can be applied to the above-described second to sixth embodiments.

  As shown in FIG. 13, the radioactive gas removal device 1 of this embodiment has a configuration in which a gas from which a radioactive substance contained in a radioactive gas that may exist in the local space 100 is removed is opened to the outside air. In this case, the communication path 6Ba of the switching unit 6 (or the communication path 15a of the switching unit 15) is connected to the local space 100, and the gas that has passed through the radioactive gas filter 5 flows through the switching unit 6 (or the switching unit 15). When the flow path is discharged outside the path 2, the gas is returned to the local space 100. When applied to the third embodiment, as shown in FIG. 9, the communication path 6Ba (or the communication path 15a) is connected to the upstream side of the heating unit 4, and the switching unit 6 (or the switching unit 15) is connected to the upstream side. In the case of a flow path for discharging the gas that has passed through the radioactive gas filter 5 to the outside of the flow passage 2, the gas is circulated upstream of the heating unit 4. The first temperature detection unit 7 is disposed in the local space 100.

  Therefore, referring to FIG. 6, the radioactive gas removal apparatus 1 of the present embodiment, for example, when an accident occurs in a nuclear facility (step S1), the control unit 9 operates the blower 3 (step S2), The first on-off valve 6A of the switching unit 6 is closed to close the other end 2b of the flow passage 2, and the second on-off valve 6B is opened to open the flow passage 2 to the outside, or the switching unit 15 is switched (step) S3). By doing in this way, the gas of the local space 100 which distribute | circulates in the flow path 2 from the one end 2a and passes the radioactive gas filter 5 passes through the flow path 2, and passes through the communication path 6Ba (communication path 15a). It is not discharged outside the local space 100. Thereafter, the control unit 9 acquires the temperature (outside temperature) detected by the first temperature detection unit 7, and when this temperature is equal to or lower than the set temperature (5 ° C. in the present embodiment) (step S4: Yes), The heating unit 4 is operated (step S5). Thereafter, the control unit 9 acquires the temperature detected by the second temperature detection unit 8 (the filter temperature that has passed through the radioactive gas filter 5), and this temperature is equal to or higher than a predetermined temperature (10 ° C. in the present embodiment). (Step S6: Yes), the first opening / closing valve 6A of the switching unit 6 is opened to open the other end 2b of the flow passage 2, the second opening / closing valve 6B is closed, and the flow passage 2 is closed to the outside (step). S7) This control is terminated. By doing in this way, the gas which distribute | circulates in the flow path 2 from the one end 2a, becomes more than preset temperature, and passes the radioactive gas filter 5 passes through the flow path 2, and is discharge | released to air | atmosphere. When the temperature is lower than the predetermined temperature in step S6 (step S6; No), the filter temperature is monitored until the temperature becomes equal to or higher than the predetermined temperature. If the set temperature is exceeded in step S4 (step S4: No), the first opening / closing valve 6A of the switching unit 6 is opened, the other end 2b of the flow passage 2 is opened, and the second opening / closing valve 6B is closed. The flow path 2 is closed with respect to the outside (step S7).

  As described above, when the outside air (local space 100) temperature is equal to or lower than the set temperature, the radioactive gas removing device 1 of the present embodiment returns to the atmosphere until the relative humidity at which element removal efficiency is obtained by the radioactive gas filter 5 is obtained. The release of the gas can be stopped, and the gas in the range where the desired iodine removal efficiency can be obtained by the radioactive gas filter 5 can be released to the atmosphere. As a result, it can be used in a state in which the removal performance of the radioactive gas is ensured.

  In each of the above-described embodiments, although not explicitly shown in the drawings, the flow passage 2 is configured as one cylindrical casing, and the blower 3, the heating unit 4, and the radioactive gas filter 5 (filter unit) are included therein. ) May be provided and configured as an integral unit.

DESCRIPTION OF SYMBOLS 1 Radioactive gas removal apparatus 2 Flow path 2a One end 2b Other end 3 Blower 4 Heating part 5 Radioactive gas filter 6 Switching part 6A 1st on-off valve 6B 2nd on-off valve 6Ba Communication path 7 1st temperature detection part 8 2nd temperature detection part DESCRIPTION OF SYMBOLS 9 Control part 10 3rd temperature detection part 11 Heating part 12 Thermal insulation part 15 Switching part 15a Communication path 50 Room 51 Exhaust part 100 Local space

Claims (5)

A flow passage forming a series of passages through which gas can flow,
A blower for circulating gas from one end of the flow passage to the other end;
A heating section for heating the gas in the flow path;
A radioactive gas filter for removing radioactive substances contained in the gas in the flow path on the downstream side of the heating unit;
A switching unit provided on a downstream side of the radioactive gas filter and in front of the other end of the flow passage to open and close the other end of the flow passage and open and close the flow passage to the outside; ,
A first temperature detector for detecting the temperature of the gas outside the flow path;
A second temperature detector for detecting the temperature of the gas in the flow path and downstream of the radioactive gas filter;
With the operation of the blower, the other end side of the flow passage is closed and the flow passage is opened to the outside to control the switching unit, and the temperature detected by the first temperature detection unit is set. When the temperature is equal to or lower than the temperature, the heating unit is operated, and then the other end of the flow path when the temperature detected by the second temperature detection unit reaches a predetermined temperature higher than the temperature of the first temperature detection unit. A control unit that opens the side and closes the flow path with respect to the outside to control the switching unit;
A radioactive gas removal apparatus comprising: A third temperature detection unit that detects a temperature of the gas in the flow path and between the heating unit and the radioactive gas filter;
When the temperature detected by the third temperature detection unit does not exceed the temperature detected by the first temperature detection unit, the control unit closes the other end side of the flow passage and makes the flow passage outside. 2. The radioactive gas removal device according to claim 1, wherein the switching unit is controlled by opening the switch.   3. The radioactive ray according to claim 1, further comprising a communication passage that connects a portion of the switching portion that opens and closes the flow passage to the outside and an upstream side of the heating portion in the flow passage. Gas removal device.   The radioactive gas removal device according to any one of claims 1 to 3, further comprising a heating unit that heats a gas that reaches the radioactive gas filter.   The radioactive gas removal device according to any one of claims 1 to 4, further comprising a heat retaining unit for retaining the temperature of the device.

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