JPS6345554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a central control room ventilation system, and particularly to a central control room ventilation system suitable for reducing radiation exposure to operators in the event of an accident.

A conventional central control room ventilation system is shown in FIGS. 1 and 2. The system in Figure 1 is an example in which a central control room ventilation system is installed independently for each adjacent nuclear power plant, and the system in Figure 2 is an example in which a part of the central control room ventilation system is shared by each adjacent nuclear power plant. This is an example. 1 is a central control room for one nuclear power plant, and 10 is a central control room for other nuclear plants.

1 and 2, in the event of an accident, an outside air intake damper 3 and an exhaust isolation damper 4 installed in an outside air intake duct 2 connected to a central control room 1 are closed during normal operation. However, as the CO ₂ concentration in the central control room 1 increases over time, the outside air is transferred to the outside air intake louver 5 and the emergency outside air intake damper 6.
The CO 2 concentration is then taken into the central control room 1 through an emergency iodine removal filter 7 to reduce the CO ₂ concentration. In addition, in order to reduce the thyroid radiation exposure of operators in the central control room 1 due to inhalation of radioactive iodine taken into the central control room 1, the air flowing through the recirculation system 8 connected to the central control room 1 is Part or all of the air passes through the recirculation system damper 9, which was opened at the time of the accident, and the air is passed through the emergency iodine removal filter 7.
After processing in the central control room 1, it is returned to the central control room 1. However, if the radioactivity concentration of the outside air is high at the time of an accident, the radioactivity concentration of the outside air taken in from the outside air intake louver 5 will be high, and even though it is being processed by the emergency iodine removal filter 7, the central control room 1 The radioactivity concentration inside will also increase somewhat.

An object of the present invention is to provide a central control room ventilation system that can suppress the increase in radioactivity concentration in the central control room during an accident and reduce the exposure dose of operators.

A feature of the present invention is that the first outside air intake louver
A first emergency ventilation intake damper that is connected through an air passage and opened in an emergency, and a first emergency filter provided in a second air passage that guides air from the first emergency ventilation intake damper to the first central control room. , a first exhaust passage provided in a first exhaust passage connected to a first central control room.
a first central control room ventilation system having an exhaust damper and a first radiation monitor that measures the radioactive concentration of air flowing into the first outside air intake louver; an outside air intake louver, a second emergency ventilation intake damper that is connected to the second outside air intake louver through a third air passage and is opened in an emergency, and a second emergency ventilation intake damper that guides air from the second emergency ventilation intake damper to the second central control room. 4. The radioactive concentration of the air flowing into the second emergency filter installed in the air passage, the second exhaust damper installed in the second exhaust passage connected to the second central control room, and the second outside air intake louver. a second central control room ventilation system having a second radiation monitor for measuring and communicating with the second air passageway upstream of the first emergency filter and communicating with the fourth air passageway upstream of the second emergency filter; a fifth air passageway provided with a first isolation valve;
a sixth air passage connected to the first exhaust passage on the upstream side of the first exhaust damper and connected to the second exhaust passage on the upstream side of the second exhaust damper and provided with a second isolation valve; In this step, the emergency ventilation intake damper of the central control room ventilation system, which is provided with a radiation monitor that outputs the lower measured value of the first radiation monitor and the second radiation monitor, is opened to open the other central control room ventilation device. The emergency ventilation intake damper of the room ventilation system is closed, and the first and second
This is because the isolation valve is configured to open.

A central control room ventilation system which is a preferred embodiment of the present invention will be described with reference to FIGS. 3 and 4.
3 corresponds to FIG. 1, and FIG. 4 corresponds to FIG. 2.

The outside air intake louver 5 is normally connected to the central control room 1 through an outside air intake duct 2 in which an outside air intake damper 3 and a blower are installed. An emergency outside air intake damper 6 is connected to the outside air intake duct 2 on the upstream side of the normal outside air intake damper 3 through an air passage. The emergency iodine removal filter 7 is
It is connected to the emergency outside air intake damper 6 through another air passage, and is also connected to the outside air intake duct 2 between the outside air intake damper 3 and the blower during normal operation via another blower. A recirculation system 8 connected to the central control room 1 is connected to the upstream side of the emergency iodine removal filter 7 via a recirculation system damper 9.
A radiation monitor 19 that measures the radioactive concentration of the outside air passing through the outside air intake louver 5 is installed near the outside air intake louver 5. Exhaust isolation damper 4
A first exhaust duct with a duct is connected to the central control room 1. The above configuration is the configuration of the ventilation system for the central control room 1.

A ventilation system having a similar configuration is also provided for the other central control room 10. That is,
The outside air intake louver 14 normally connects to the outside air intake duct 1 in which an outside air intake damper 12 and a blower are installed.
1 to the central control room 10. The outside air intake louver 14 is installed at a location away from the outside air intake louver 5 described above. The emergency outside air intake damper 15 is connected to the outside air intake duct 1 on the upstream side of the normal outside air intake damper 12 via an air passage.
1 has been contacted. The emergency iodine removal filter 16 is connected to the emergency outside air intake damper 15 through another air passage, and is also connected to the outside air intake duct 11 between the outside air intake damper 12 and the blower during normal operation via another blower. ing. A recirculation system 18 connected to the central control room 10 is connected to an emergency iodine removal filter 16 via a recirculation system damper 17.
will be communicated to the upstream side. A radiation monitor 20 that measures the radioactive concentration of the outside air passing through the outside air intake louver 14 is installed near the outside air intake louver 14. A second exhaust duct with an exhaust isolation damper 13 is connected to the central control room 10 .

Further, a pipe 23 having an isolation valve 21 is connected to an air passage connecting the emergency outside air intake damper 6 and the emergency iodine removal filter 7 on the upstream side of the emergency iodine removal filter 7, and It is connected to an air passage connecting the emergency outside air intake damper 15 and the emergency iodine removal filter 16 on the upstream side of the iodine removal filter 16 . A pipe 23 with an isolation valve 22 is connected upstream of the exhaust isolation damper 4 to the first exhaust duct and upstream of the exhaust isolation damper 13 to the second exhaust duct.

In normal times when the nuclear reactor is operating normally in a nuclear power plant equipped with the central control room 1 and a nuclear power plant equipped with the central control room 10,
In the ventilation system for the central control room 1, outside air flowing in from the outside air intake louver 5 passes through the outside air intake damper 3, which is normally open, and is guided into the central control room 1 through the outside air intake duct 2. At this time, the emergency outside air intake damper 6 and the recirculation system damper 9 are closed. Exhaust air from the central control room 1 is discharged to the outside environment through a first exhaust duct in which the exhaust isolation damper 4 is open. In addition, in the ventilation system for the central control room 10, the outside air flowing in from the outside air intake louver 14 during normal times is
The air is guided into the central control room 10 through the outside air intake duct 11 through the outside air intake damper 12 which is normally open. At this time, the emergency outside air intake damper 15
and the recirculation system damper 17 is closed. Exhaust gas from the central control room 10 is discharged to the outside environment through a second exhaust duct in which the exhaust isolation damper 13 is open.

When an accident occurs at one of the nuclear power plants and the radioactivity concentration in the external environment increases,
Normally, the outside air intake dampers 3 and 12 are closed, and the emergency outside air intake dampers 6, 15 and the recirculation system dampers 9, 17 are opened. The radioactive concentration of the outside air near the outside air intake louvers 5 and 14 is detected by the radiation monitor 19.
and 20, respectively. The emergency outside air intake damper of the ventilation system in which the radiation monitor exhibiting a low measured radioactivity concentration among the radiation monitors 19 and 20 is installed is closed.
At the same time, isolation valves 21 and 22 are opened, and exhaust isolation dampers of ventilation systems in which radiation monitors showing low radioactivity concentrations are not installed are closed. For example, assume that the measured value of the radiation monitor 19 becomes lower than that of the radiation monitor 20 at the time of an accident. Based on this result, the emergency outside air intake damper 15 is closed and the exhaust isolation damper 13 is closed. Isolation valves 21 and 22 are naturally open. In such a state, outside air with a low radioactivity concentration is taken into the central control room 1 via the outside air intake louver 5, the emergency outside air intake damper 6, and the emergency iodine removal filter 7. Also, some of that outside air is
After passing through the emergency outside air intake damper 6, the pipe 2
3 and an emergency iodine removal filter 16 into the central control room 10. Part or all of the air flowing through the recirculation system 8 connected to the central control room 1 is passed through the recirculation system damper 9 and treated by the emergency iodine removal filter 7, and then returned to the central control room 1. I'm returning it. Similarly, the central control room 10
A part or all of the air flowing through the recirculation system 18 connected to the recirculation system 18 passes through the recirculation system damper 17 and is treated with the emergency iodine removal filter 16.
It has been returned to the central control room 10.

According to this embodiment described above, the following effects can be obtained.

(1) Reduction of exposure dose Figure 5 shows an example of the relationship between the outside air intake rate and the exposure dose at the time of an accident. The outside air intake rate under normal conditions is 1 time/h. However, when an outside air taken in from one outside air intake louver is supplied to two nuclear power plants at the time of an accident as in this embodiment, the outside air intake rate per plant is 0.5 times/h. Therefore, the radiation dose to the operators in the central control room is a small value compared to other outside air intake rates.

Further, since the outside air intake louvers 5 and 14 are installed at locations apart from each other, the radioactivity concentration differs significantly in the vicinity of each outside air intake louver depending on the wind direction. In this embodiment, the outside air intake louver 5
and 14, outside air is taken in from outside air intake louvers that can take in outside air with low radioactivity concentration in the event of an accident, and it is guided into central control rooms 1 and 10, so the radioactivity concentration in central control rooms 5 and 14 is can be significantly reduced. Therefore, the exposure dose of the operators in each central control room can be further reduced.

(2) Reduction of CO ₂ concentration Figure 6 shows an example of the relationship between outside air intake rate and CO ₂ concentration at the time of an accident.

In this example, in the event of an accident, outside air is taken into each central control room at a rate of 0.5 times/h as described above, so the CO ₂ concentration in the central control room is
It can be kept to 0.1% or less, and the office
The CO ₂ permissible concentration of 0.5% can be fully satisfied.

According to the present invention, the outside air intake louvers provided for each central control room are installed further apart from each other, and the outside air is drawn from the outside air intake louver located at a location where radioactivity concentration is lower at the time of an accident. Since the radioactivity is taken in and supplied to each central control room, the radioactivity concentration in each central control room can be significantly lowered in the event of an accident, and the exposure dose of operators in these central control rooms can be significantly reduced.

[Brief explanation of the drawing]

Figures 1 and 2 are block diagrams of a conventional central control room ventilation system, Figures 3 and 4 are block diagrams of a central control room ventilation system according to an embodiment of the present invention, and Figure 5 is a diagram showing the outside air intake rate. Figure 6 is a characteristic diagram showing the relationship between exposure dose and the relationship between outside air intake rate and CO ₂ concentration. 1, 10... Main control room, 2, 11... Outside air intake duct, 3, 12... Normal time outside air intake damper, 4, 13... Exhaust isolation damper, 5, 14...
Outside air intake louver, 6, 15... Emergency outside air intake damper, 7, 16... Emergency element removal filter, 21, 22... Isolation valve, 23, 24... Piping.

Claims (1)

[Claims] 1 a first outside air intake louver, a first emergency ventilation intake damper that is connected to the first outside air intake louver through a first air passage and is opened in an emergency, and a first central control from the first emergency ventilation intake damper; a first emergency filter provided in a second air passage leading air into the room; a first emergency filter connected to the first central control room;
a first central control room ventilation system including a first exhaust damper provided in an exhaust passage and a first radiation monitor that measures the radioactivity concentration of air flowing into the first outside air intake louver; and the first outside air intake louver. a second outside air intake louver installed at a location away from the second outside air intake louver, a second emergency ventilation intake damper that is connected to the second outside air intake louver through a third air passage and is opened in an emergency, and the second emergency ventilation intake. a second emergency filter provided in a fourth air passage that guides air from a damper to the second central control room; a second exhaust damper provided in a second exhaust passage connected to the second central control room; a second central control room ventilation system having a second radiation monitor that measures the radioactivity concentration of air flowing into the second outside air intake louver; and a second central control room ventilation system connected to the second air passageway upstream of the first emergency filter. a fifth air passage connected to the fourth air passage on the upstream side of the second emergency filter and provided with a first isolation valve; and a fifth air passage connected to the first exhaust passage on the upstream side of the first exhaust damper. and a sixth air passage connected to the second exhaust passage on the upstream side of the second exhaust damper and provided with a second isolation valve, in the event of an accident, the first radiation monitor and the second radiation The emergency ventilation intake damper of the central control room ventilation system, which is provided with a radiation monitor that outputs a lower measured value among the monitors, is opened, and the emergency ventilation intake damper of the other central control room ventilation system is opened. 2. A central control room ventilation system configured to close the valve and open the first and second isolation valves.