JPH0634065B2 - Ventilation and air conditioning equipment for nuclear power plants - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a ventilation and air conditioning equipment for a nuclear power plant, and in particular,
The present invention relates to a ventilation air conditioning system for a nuclear power plant that prevents abnormal pressure fluctuations in a highly air-tight air-conditioned space such as a reactor building.

[Technical background of the invention and its problems]

Generally, a nuclear power plant has various buildings, but a reactor building has a particularly high airtightness, and its ventilation and air conditioning equipment is configured as shown in FIG.

Since the reactor building 1 accommodates the reactor containment vessel 2, it is made of concrete and has no window, and is constructed as a structure having a very high airtightness to prevent leakage of radioactive materials such as accidents. The ventilation and air conditioning equipment of the reactor building 1 includes an air supply fan 4a of the air supply duct 3 and an exhaust fan 6a of the exhaust duct 5.
Standby machines 4b and 6b are provided in and respectively. The air supply duct 3 takes in outside air from the outside air intake louver 7 by operating the air supply fan 4a, and removes foreign matter in the outside air from the outside air filter 8
It is removed and purified by the heating coil 9 or the cooling coil 1.
This air is supplied to each room 1a in the reactor building 1 after the temperature is adjusted to an appropriate temperature at 0.

On the other hand, the exhaust duct 5 operates the exhaust fan 6a to exhaust the exhaust gas from each chamber 1a in the reactor building 1 into the exhaust filter 11
In this case, the radioactive substances are removed to purify the exhaust gas, and the exhaust gas is discharged from the exhaust stack 12 to the outside air.

In FIG. 2, reference numeral 13 is an air supply isolation valve, and 14 is an exhaust isolation valve.

However, in such a conventional ventilation and air conditioning equipment for a nuclear power plant, the air supply fan 4a or the exhaust fan 6a is switched to each of the standby units 4b and 6b, or the air supply fan 4 is used.
If a lameness operation of the air supply / exhaust fan is temporarily performed due to a failure of either a or the exhaust fan 6a, the inside of the reactor building 1 having high airtightness becomes negative pressure or positive pressure, and the reactor building 1
There was a risk of damaging the equipment entrance door, etc. (not shown). Also, even if it is not damaged, the drain hole is completely sealed with water,
Alternatively, an unfavorable influence on the soundness of the reactor building 1, such as an external pressure being applied to the primary reactor containment vessel, can be considered. Therefore, when a pressure imbalance occurs on the air supply / exhaust side due to such a lameness operation of the air supply / exhaust fan,
It is conceivable that the balance of the supply / exhaust side pressure is restored by closing the damper of either the supply / exhaust duct 3 or 5. For example, it is conceivable to close the damper (not shown) of the exhaust duct 5 and forcibly reduce the exhaust amount so that the inside of the reactor building 1 does not become a negative pressure during the switching of the air supply fan 74a to the standby unit 4b. . However, this
Since the current value of the exhaust fan 6a during driving is reduced to reduce the air flow rate, the low air flow rate detection device (not shown) indicates “low air flow rate”.
There is a problem that the exhaust fan 6a is also stopped by detecting the state.

[Object of the Invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a ventilation and air conditioning equipment for a nuclear power plant that prevents abnormal pressure fluctuations in the air-conditioned space due to lame operation of the air supply and exhaust fans.

[Outline of Invention]

In order to achieve the above-mentioned object, the present invention relates to a ventilation air-conditioning facility of a nuclear power plant in which an air supply duct having an air supply fan and an exhaust duct having an exhaust fan are provided in an air-conditioned space such as a building. A bypass air supply valve provided in an air supply bypass passage that connects upstream and downstream of the air supply fan, and an exhaust bypass passage that connects the upstream of the air supply fan of the air supply duct and the upstream of the exhaust fan of the exhaust duct. An exhaust bypass valve, a differential pressure detector that detects the differential pressure between the pressure in the air-conditioned space and the external atmospheric pressure, and the detection output from this differential pressure detector is compared with a set value to determine the difference pressure. And a differential pressure controller for opening the bypass air supply valve or the bypass exhaust valve.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIG. The same parts as those in FIG. 2 are designated by the same reference numerals.

The reactor building 1 accommodates a reactor containment vessel 2, and each room 1a is provided with branch ducts 3a and 5a of an air supply duct 3 and an exhaust duct 5, respectively.

The air supply duct 3 penetrates the reactor building 1 and extends to the outside thereof, and an outside air intake louver 7 is attached to an outside air intake louver opening to the outside air. From this, an outside air filter 8 and a heating coil 9 are provided downstream. , The cooling coil 10, the air supply fan 4a, and the air supply isolation valve 13 are sequentially provided in this order, and the standby unit 4 is installed in the air supply fan 4a.
b are provided in parallel.

Further, in the air supply duct 3, an intermediate portion between the outside air intake louver 7 and the outside air filter 8, the air supply fan 4a and its spare unit 4 are provided.
An air supply bypass passage 20 that connects the intermediate portion of b to the exhaust isolation valve 13 is provided, and an air supply bypass valve 21 is provided in the middle of the air supply bypass passage 20.

On the other hand, the exhaust duct 5 penetrates the reactor building 1 and extends to the outside thereof, and the exhaust isolation valve 14 is interposed between the exhaust duct 5, the exhaust filter 11, the exhaust fan 6a, and the exhaust pipe 12 in the downstream direction. The exhaust fan 6a is provided with a spare device 6 in order.
b are provided in parallel.

In the middle of the exhaust duct 5 connecting the exhaust isolation valve 14 and the exhaust filter 11, the outside air intake louver 7 and the outside air filter 8 in the air supply duct 3 are communicated via an exhaust bypass passage 22. An exhaust bypass valve 23 is provided in the middle of the passage 22.

The reactor building 1 is provided with a differential pressure detector 24 for detecting a differential pressure between its internal pressure and external atmospheric pressure, and the differential pressure detector 24 is provided with a supply air bypass valve 21 and an exhaust bypass valve 23 via a differential pressure controller 25. And are electrically connected respectively. That is, the differential pressure detection output from the differential pressure detector 24 is given to the differential pressure controller 25, where the differential pressure set value, for example, −5.
About 10 mmAq, the difference pressure between the two is converted into an opening signal of the required opening, and the air supply and exhaust bypass valves 21, 2 are
The valve opening is controlled so that the deviation pressure becomes zero by being applied to any one of No. 3 and No. 3.

Next, the operation of this embodiment will be described.

When both the air supply fan 4a and the exhaust fan 6a are operating soundly, the differential pressure between the internal pressure and the external atmospheric pressure in the reactor building 1 detected by the differential pressure detector 24 is within the differential pressure set value. Therefore, the air conditioning of each room 1a in the reactor building 1 is performed by substantially the same operation as described in the conventional example.

However, if the ventilation fan 4a fails for some reason and stops its operation, the operation of the exhaust fan 6a is stopped until the air supply fan 4a recovers or the standby unit 4b starts up. Continuing, the lameness operation is performed by the exhaust fan 6a.

For this reason, the supply to the reactor building 1 is stopped and the gas is unilaterally exhausted, so that the degree of negative pressure in the reactor building 1 becomes large and the differential pressure from the outside air pressure becomes large. This differential pressure is detected by the differential pressure detector 24, compared with the differential pressure setting value of the differential pressure controller 25, and the differential pressure is converted into a valve opening signal for opening to the required valve opening degree, and the exhaust bypass valve 23 The exhaust bypass valve 23 is controlled to open to the required opening degree, and the exhaust bypass passage 22 is made conductive. As a result, the outside air taken in from the outside air intake louver 7 is transferred to the reactor building 1
Is introduced to the upstream side of the outside air filter 11 of the exhaust duct 5 via the exhaust bypass passage 22 that bypasses and is conducted, and is discharged from the exhaust pipe 12 to the outside air by the exhaust fan 6a in operation. Therefore, the air discharged by the exhaust fan 6a during operation is mainly the outside air taken in from the outside air intake louver 7 of the air supply duct 3, so that the amount of discharge from the inside of the reactor building 1 to the outside air is It is remarkably reduced and the negative pressure in the reactor building 1 is not increased. Further, since the damper (not shown) of the exhaust duct 5 is not closed, the exhaust fan 6
It does not stop the operation of a.

During the opening of the exhaust bypass valve 23, the air supply fan 4a recovers or switches to the standby unit 4b to increase the air supply amount into the reactor building 1 and reduce the negative pressure level in the reactor building 1. Is restored to the set value, the differential pressure detected by the differential pressure detector 24 is restored within the differential pressure set value of the differential pressure controller 25. As a result, the output of the valve opening signal from the differential pressure controller 25 is stopped, the exhaust bypass valve 23 is closed, and the exhaust bypass passage 22 is closed, so that the outside air taken in from the outside air intake louver 7 is again supplied to the air supply duct. Air is supplied into the reactor building 1 via

On the other hand, when the air in the reactor building 1 is not forcibly discharged due to the failure of the exhaust fan 6a or the switching to the spare unit 6b, the air supply fan 4a continues to operate, so the reactor building Only air supply is done in 1.
The inside of the reactor building 1 turns from negative pressure to positive pressure. This positive pressure state is detected by the differential pressure detector 24, and the differential pressure controller 25 gives a valve opening signal to the air supply bypass valve 21. As a result, the supply air bypass valve 21 is opened to the required opening degree, and the supply air bypass passage 20 is made conductive, so that the outside air taken in from the outside air intake louver 7 by the operating supply air fan 4a is made conductive. After being guided to the air supply bypass passage 20, the air is returned to the downstream side of the outside air intake louver 7, and the forced air supply into the reactor building 1 is almost stopped. Therefore, it is possible to prevent the positive pressure in the reactor building 1 from increasing thereafter.

Further, the exhaust fan 6a is recovered while the air supply bypass valve 21 is open, or the standby fan 6b is switched to increase the exhaust amount from the inside of the reactor building 1 and the negative pressure inside the reactor building 1 is increased. When the set value is restored, the output of the valve opening signal from the differential pressure controller 25 is stopped, the supply air bypass valve 21 is closed, and the supply air bypass passage 20 is closed.

However, while the air supply bypass valve 21 is open, the exhaust fan 6a
Is not recovered or the standby machine 6b is not switched to, the operation of the ventilation and air conditioning equipment is completely stopped. This is the same when the air supply fan 4a does not recover or does not switch to the standby unit 4b while the exhaust bypass valve 23 is open.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention provides a ventilation air conditioner for a nuclear power plant in which an air supply duct having an air supply fan and an exhaust duct having an exhaust fan are provided in an air-conditioned space such as a building. A bypass air supply valve provided in the air supply bypass passage that connects the upstream side and the downstream side of
An exhaust bypass valve provided in an exhaust bypass passage that connects the upstream of the air supply fan of the air supply duct and the upstream of the exhaust fan of the exhaust duct, and a difference that detects the differential pressure between the pressure in the air-conditioned space and the external atmospheric pressure. It has a pressure detector and a differential pressure controller which compares a detection output from the differential pressure detector with a set value and opens the bypass air supply valve or the bypass exhaust valve according to the deviation pressure.

Therefore, according to the present invention, when the lameness operation of the fan is performed due to a failure of either the air supply fan or the exhaust fan, the air supply or the exhaust air is supplied through the air supply bypass passage or the exhaust bypass passage. Since the air is evacuated and the air-conditioned space such as the reactor building is bypassed, it is possible to prevent abnormal pressure fluctuations in the air-conditioned space even in this case. Moreover, since the sound supply fan or the exhaust fan is continuously operated, it is possible to prevent the ventilation and air conditioning equipment from being completely stopped.

[Brief description of drawings]

FIG. 1 is a piping system diagram of an embodiment of ventilation and air conditioning equipment for a nuclear power plant according to the present invention, and FIG. 2 is a piping system diagram of a conventional example. 1 ... Reactor building, 2 ... Reactor containment vessel, 3 ... Air supply duct, 4a ... Air supply fan, 5 ... Exhaust duct, 6a
...... Exhaust fan, 20 ...... Air supply bypass passage, 21 ...... Air supply bypass valve, 22 ...... Exhaust bypass passage, 23 ...... Exhaust bypass valve, 24 ...... Differential pressure detector, 25 ...... Differential pressure controller.

Claims (1)

[Claims] 1. A ventilation air conditioner for a nuclear power plant in which an air supply duct having an air supply fan and an exhaust air duct having an exhaust fan are provided in an air-conditioned space such as a building, and the upstream and downstream sides of the air supply fan in the air supply duct. A bypass air supply valve provided in an air supply bypass passage communicating with the exhaust gas, and an exhaust air bypass valve provided in an exhaust bypass passage communicating between the upstream of the air supply fan of the air supply duct and the upstream of the exhaust fan of the exhaust duct. , A differential pressure detector for detecting the differential pressure between the pressure in the air-conditioned space and the outside air pressure, and a detection output from this differential pressure detector is compared with a set value, and the bypass air supply valve or according to the deviation pressure thereof. A ventilation air conditioner for a nuclear power plant, comprising: a differential pressure controller that opens a bypass exhaust valve.