JP7645769B2 - Ventilation systems for nuclear facilities - Google Patents

Description

This disclosure relates to ventilation systems for nuclear facilities.

Nuclear power plants and other nuclear facilities are equipped with ventilation systems for ventilation and air conditioning. This type of ventilation system mainly comprises a duct installed inside the building and a fan (blower) that pressurizes the air inside the duct. The following Patent Document 1 discloses a technology for centrally controlling the rotation speed of the fan in such a ventilation system using an inverter.

JP 2006-317236 A

However, nuclear facilities require a particularly high level of earthquake resistance compared to normal facilities. For this reason, earthquake resistance is also important when selecting inverters such as those mentioned above, and expensive inverters are used, which is a factor in pushing up the construction and maintenance costs of the facilities.

This disclosure has been made to solve the above problems, and aims to provide a ventilation system for nuclear facilities that can be constructed at lower cost.

In order to solve the above problems, the ventilation system for a nuclear facility according to the present disclosure comprises a plurality of main ducts arranged in parallel with each other, fans provided in each of the main ducts and each having a different air flow rate, check valves provided between the fans and a first chamber in each of the main ducts and allowing air to flow only in either one of the directions from the first chamber toward the fan and from the fan toward the first chamber, and first connecting ducts communicating each of the check valves with the first chamber, and further comprises a second connecting duct connected in the main duct between the fan and the check valve and communicating with a second chamber.

This disclosure makes it possible to provide a ventilation system for a nuclear facility that can be constructed at lower cost.

FIG. 2 is a schematic diagram showing the configuration of the ventilation system for the nuclear facility according to the first embodiment of the present disclosure, illustrating a state in which only the first fan is operating. FIG. 2 is a schematic diagram showing the configuration of the ventilation system for the nuclear facility according to the first embodiment of the present disclosure, illustrating a state in which only the second fan is operating. FIG. 2 is a schematic diagram showing a modified example of the ventilation system for the nuclear facility according to the first embodiment of the present disclosure. FIG. 13 is a schematic diagram showing the configuration of a ventilation system for a nuclear facility according to a second embodiment of the present disclosure. FIG. 13 is a schematic diagram showing a modified example of the ventilation system for the nuclear facility according to the second embodiment of the present disclosure. FIG. 13 is a schematic diagram showing the configuration of a ventilation system for a nuclear facility according to a third embodiment of the present disclosure. FIG. 13 is a schematic diagram showing a modified example of the ventilation system for the nuclear facility according to the third embodiment of the present disclosure.

First Embodiment
Hereinafter, a ventilation system 1 for a nuclear facility according to a first embodiment of the present disclosure will be described with reference to Fig. 1 and Fig. 2. Hereinafter, the ventilation system 1 for a nuclear facility will be simply referred to as the "ventilation system 1." The ventilation system 1 is installed in a building of a nuclear power plant and is used to ventilate and air-condition the building.

(Configuration of ventilation system)
As shown in FIG. 1 , the ventilation system 1 includes a plurality of (two) main ducts 20 , a plurality of (two) fans 30 , a plurality of (two) check valves 40 , and a first connecting duct 50 .

The two main ducts 20 extend in parallel to each other. In the following, the main duct 20 on one side is referred to as the first main duct 21, and the main duct 20 on the other side is referred to as the second main duct 22. One end of the first main duct 21 and the second main duct 22 communicates with the first chamber 10 via the first connecting duct 50. The first chamber 10 is any space that is to be ventilated within the nuclear facility. The first chamber 10 is provided with a ventilation opening 11 that communicates with the outside. The other ends of the first main duct 21 and the second main duct 22 are each open to the outside or connected to a filter device or the like.

On the first main duct 21, a fan 30 (first fan 31) and a check valve 40 are provided in this order from the first chamber 10 side to the outside. The first fan 31 pressurizes and sends air in a direction from the first chamber 10 to the outside. The first fan 31 is a fixed-volume fan that operates at a predetermined constant air volume. In other words, the first fan 31 only has one mode, either an operating state or a stopped state. The check valve 40 is provided upstream of the first fan 31. The check valve 40 allows air to flow only in the direction from the first chamber 10 side to the outside (the first fan 31 side). The check valve 40 includes not only a valve device but also a damper.

On the second main duct 22, a fan 30 (second fan 32) and a check valve 40 are provided in this order from the first chamber 10 side to the outside. The second fan 32 pressurizes and sends air in a direction from the first chamber 10 to the outside. The second fan 32 is a fixed-volume fan that operates at a predetermined constant airflow rate. In other words, the second fan 32 has only one mode, either an operating state or a stopped state. The airflow rate of the second fan 32 is set to be smaller than the airflow rate of the first fan 31. The check valve 40 is provided upstream of the second fan 32. The check valve 40 allows air to flow only in a direction from the first chamber 10 side to the outside (second fan 32 side).

(Action and Effect)
Next, an example of the operation of the ventilation system 1 will be described. Fig. 1 shows a state in which only the first fan 31 is operating. As shown in the figure, when only the first fan 31 is operating, the air in the first room 10 flows into the first main duct 21 through the first connection duct 50. The air that flows into the first main duct 21 passes through the check valve 40 and the first fan 31 and is released to the outside. In the first room 10, the air that flows out from the first connection duct 50 is supplemented by the air that flows in from the ventilation port 11. In other words, the first room 10 is ventilated.

Here, there is a demand to change the ventilation volume of the first chamber 10. In this case, as shown in FIG. 2, the first fan 31 is stopped and only the second fan 32 is operated. Then, the air in the first chamber 10 flows into the second main duct 22 through the first connection duct 50. The air that flows into the second main duct 22 passes through the check valve 40 and the second fan 32 and is released to the outside. Here, the air volume of the second fan 32 is set to be smaller than the air volume of the first fan 31. Therefore, the amount of air flowing out of the first chamber 10 is smaller when the second fan 32 is operating than when the first fan 31 is operating. In other words, the ventilation volume of the first chamber 10 is reduced. In this way, it is possible to easily change the ventilation volume of the first chamber 10 by simply switching the operating states of the first fan 31 and the second fan 32.

As explained above, according to the above configuration, the fans 30 with different airflow rates are provided on the main duct 20. As a result, by operating only one of the fans 30, the ventilation rate of the first chamber 10 can be adjusted according to the airflow rate of each fan 30. In particular, the ventilation rate can be changed without using an inverter or the like for changing the rotation speed or airflow rate of the fan 30. This makes it possible to reduce the construction and maintenance costs of the facility. In particular, since high earthquake resistance is required for control equipment such as inverters in nuclear facilities, adopting a configuration that does not require such control equipment provides not only cost benefits but also maintenance benefits.

The above describes the first embodiment of the present disclosure. It should be noted that various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the above first embodiment, a state in which either the first fan 31 or the second fan 32 is selectively operated has been described. However, it is also possible to operate the first fan 31 and the second fan 32 simultaneously. In this case, it is possible to obtain an even larger ventilation volume than when only the first fan 31 is operated.

In addition, in the first embodiment, only one first chamber 10 is illustrated, but as shown in FIG. 3, it is also possible to adopt a configuration including multiple first chambers 10 and multiple first connection ducts 50. In all first chambers 10, it is possible to simultaneously switch the ventilation volume in the same manner as described above.

Second Embodiment
Next, a second embodiment of the present disclosure will be described with reference to Fig. 4. Note that the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. As shown in Fig. 4, the ventilation system 1 according to this embodiment further includes a second connection duct 50b. The second connection duct 50b connects the second main duct 22 between the second fan 32 and the check valve 40 and the second chamber 10b. The second chamber 10b is an arbitrary space that is to be ventilated in the nuclear facility, similar to the first chamber 10.

According to the above configuration, by operating the second fan 32, it is possible to ventilate the second room 10b as well as the first room 10 using the second fan 32. On the other hand, when the second fan 32 is stopped and only the first fan 31 is operating, the first room 10 is ventilated but the second room 10b is not ventilated. In this way, it is desirable to select the first room 10 as a "space that requires adjustment of the amount of ventilation" and the second room 10b as a "space that does not require adjustment of the amount of ventilation and only requires adjustment of whether ventilation is being performed or not." This makes it possible to build a more efficient ventilation system 1 with a minimum of equipment configuration.

The second embodiment of the present disclosure has been described above. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, in the second embodiment, only a configuration in which one second chamber 10b is connected to the second main duct 22 by the second connection duct 50b has been described. However, as shown in FIG. 5, it is also possible to adopt a configuration in which the space between the first fan 31 and the check valve 40 in the first main duct 21 is connected to another second chamber 10c by the second connection duct 50c. In this case, in the second chamber 10c, only one of the states in which ventilation is performed by the first fan 31 with a large air volume or in which ventilation is completely stopped is selected. In other words, it is desirable to select a space that requires a larger amount of ventilation than the second chamber 10b as the second chamber 10c.

Third Embodiment
Next, a third embodiment of the present disclosure will be described with reference to FIG. 6. Note that the same reference numerals are used for the same configurations as those of the above-described embodiments, and detailed description will be omitted. As shown in FIG. 6, in the ventilation system 1 according to this embodiment, unlike the ventilation system 1 according to the first embodiment, the directions of the air flow permitted by the two check valves 40b are opposite. In other words, the check valve 40b permits air flow only in the direction from the first fan 31 (second fan 32) side toward the first chamber 10 side. In addition, the first fan 31 and the second fan 32 pump air from the outside side toward the first chamber 10 side.

According to the above configuration, when only the first fan 31 is operated, outside air is supplied into the first chamber 10 through the first main duct 21. In the first chamber 10, the air inside is discharged to the outside through the ventilation opening 11 in an amount equal to the amount of air supplied. This allows ventilation inside the first chamber 10. In addition, when the first fan 31 is stopped and only the second fan 32 is operated, ventilation can be performed with a smaller ventilation volume than when the first fan 31 is operated.

The above describes the third embodiment of the present disclosure. Various changes and modifications can be made to the above configuration without departing from the gist of the present disclosure. For example, as shown in FIG. 7, it is also possible to adopt a configuration in which the second main duct 22 and the second chamber 10b are connected to each other by the second connection duct 50b. In this case, by operating the second fan 32, it is possible to supply outside air to the second chamber 10b. Although not shown in the figure, it is also possible to provide another second connection duct 50b and a second chamber 10b on the first main duct 21 side.

<Additional Notes>
The ventilation system 1 for a nuclear facility described in each embodiment can be understood, for example, as follows.

(1) The ventilation system 1 for a nuclear facility according to the first aspect includes a plurality of main ducts 20 arranged in parallel with each other, fans 30 provided in each of the main ducts 20 and having different airflow rates, check valves 40 provided between the fans 30 and the first chamber 10 in each of the main ducts 20 and allowing air to flow only in one of the directions from the first chamber 10 toward the fans 30 and from the fans 30 toward the first chamber 10, and a first connecting duct 50 connecting each of the check valves 40 to the first chamber 10.

According to the above configuration, the fans 30 with different airflow rates are provided on the main duct 20. As a result, by operating only one of the fans 30, the ventilation rate of the first chamber 10 can be adjusted according to the airflow rate of each fan 30. In particular, the ventilation rate can be changed without using an inverter or the like for changing the rotation speed or airflow rate of the fan 30. This can reduce the construction and maintenance costs of the equipment.

(2) The second aspect of the ventilation system 1 for a nuclear facility further includes a second connection duct 50b connected between the fan 30 and the check valve 40 in the main duct 20 and communicating with the second chamber 10b of the nuclear facility.

With the above configuration, in addition to the first chamber 10, the second chamber 10b can also be ventilated using the fan 30.

(3) The ventilation system 1 for a nuclear facility according to the third aspect includes a plurality of the first connection ducts 50 that communicate with a plurality of the first chambers 10.

With the above configuration, the ventilation volumes of multiple first rooms 10 can be changed simultaneously. This makes it possible to avoid the configuration of the ventilation system 1 becoming complicated.

(4) The ventilation system 1 for a nuclear facility according to the fourth aspect includes a plurality of the second connection ducts 50b that communicate with a plurality of the second chambers 10b.

With the above configuration, the ventilation volumes of multiple second rooms 10b can be changed simultaneously. This makes it possible to avoid the configuration of the ventilation system 1 becoming complicated.

(5) In the fifth aspect of the ventilation system 1 for a nuclear facility, each of the fans 30 is a fixed-volume fan that operates at a predetermined constant air volume.

With the above configuration, since each fan 30 is a fixed-volume fan that operates at a constant air volume, the ventilation system 1 can be constructed without using control devices such as inverters. This reduces the construction and maintenance costs of the equipment.

(6) In the ventilation system 1 for a nuclear facility relating to the sixth aspect, it is possible to selectively put any one of the multiple fans 30 into an operational state, and it is also possible to put the multiple fans 30 into an operational state simultaneously.

REFERENCE SIGNS LIST 1 Ventilation system for nuclear facility 10 First chamber 10b, 10c Second chamber 11, 11b, 11c Ventilation port 20 Main duct 21 First main duct 22 Second main duct 30 Fan 31 First fan 32 Second fan 40, 40b Check valve 50 First connecting duct 50b Second connecting duct

Claims (5)

A plurality of main ducts arranged in parallel with each other;
Fans provided in the main ducts, each of which has a different airflow rate;
a check valve provided in each of the main ducts between the fan and the first chamber, and allowing air to flow only in one of a direction from the first chamber toward the fan and a direction from the fan toward the first chamber;
a first connecting duct communicating each of the check valves with the first chamber;
Equipped with
The ventilation system for a nuclear facility further comprises a second connection duct connected between the fan and the check valve in the main duct and communicating with a second chamber. The ventilation system for a nuclear facility according to claim 1, comprising a plurality of the first connection ducts communicating with a plurality of the first chambers. The ventilation system for a nuclear facility according to claim 1, comprising a plurality of the second connection ducts communicating with a plurality of the second chambers. The ventilation system for a nuclear facility according to claim 1 or 2, wherein each of the fans is a fixed-volume fan that operates at a predetermined constant air volume. 5. The ventilation system for a nuclear facility according to claim 1, wherein any one of the plurality of fans can be selectively put into an operational state, and the plurality of fans can be simultaneously put into an operational state.

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