JPS60107599A - Treating facility for emergency gas of nuclear power plant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to emergency gas processing equipment for nuclear power plants, and in particular to emergency gas processing equipment for nuclear power plants that maintains system air volume at a required design air volume. Regarding processing equipment.

[Technical background of the invention and its problems]

Generally, emergency gas treatment equipment (SGTS) in nuclear power plants
In the event of a nuclear reactor accident, the system automatically switches over from the reactor building's normal ventilation and air conditioning system, maintains negative pressure inside the reactor building, and removes fission products that have leaked out of the reactor containment vessel. This prevents the radioactive materials from dispersing into the surrounding environment, and at the same time removes the radioactive materials using a high-performance filter and releases them to the outside of the stack.

A conventional emergency gas treatment system for a nuclear power plant is constructed as shown in FIG. 1, and includes a ventilation air conditioning system 2 and emergency gas treatment equipment 3 in a reactor building 1, which is a secondary containment facility.

The ventilation air conditioning system 2 has an air supply duct) 2a that introduces outside air into the reactor building 1, and an exhaust duct) 2b that releases the air inside the reactor building 1 to the outside air. daku) 2
b is connected to an air supply header 2c and an exhaust header/2d inside the reactor building 1, and is provided with isolation valves 4 and 5 outside the reactor building 1, respectively. isolation valve 5
The emergency exhaust duct 6 of the emergency gas processing equipment 3 is connected to the upstream exhaust duct 2b of the reactor containment vessel (not shown), and the isolation valve 4 of the ventilation air conditioning system 2,
5 are both urgently closed, and ventilation in the reactor building 1 by the ventilation air conditioning system 2 is stopped. At almost the same time, the fan 7 of the emergency gas processing equipment 3 starts, and the air inside the reactor building 1 is guided to the emergency exhaust duct 6, where radioactive substances are removed by a filter, and the outside air is passed through the stack (not shown). It is designed to be released to

Further, in such conventional emergency gas processing equipment 3, the system air volume is designed to be such that the free space volume within the reactor building 1 can be treated once a day.

However, in recent nuclear power plants, the concrete that makes up the reactor building 1, etc. has become better airtight, and the airtightness of the penetration parts of the reactor building 1, etc. has improved. The airtightness of the furnace building has been improved. For this reason, in recent nuclear power plants, the system air volume of emergency gas processing equipment is 100% of the above design air volume.
For example, it decreased to about 30 to 50%. Along with this reduction in system air volume, the amount of air released in the event of an accident from the reactor containment vessel (not shown) has also been reduced, but on the other hand, the following problems have arisen. That is, reactor building 1
Problems have arisen with regard to the strength of the reactor building, as the negative pressure inside the reactor building is higher than the design value. In addition, the exhaust gas guided to the emergency exhaust duct 6 is heated by an electric heater before being released to the outside air, but there was a problem in that the temperature inside the system became higher than the design temperature because the system air volume decreased. .

[Purpose of the invention]

The present invention was developed in view of the above-mentioned circumstances, and it is necessary to introduce outside air into the reactor building to maintain the necessary negative pressure in the reactor building so that the system air volume maintains approximately the design air volume in the event of a nuclear accident. The purpose of the present invention is to provide emergency gas processing equipment in a nuclear power plant that maintains the temperature at the design value and suppresses the rise in temperature within the system.

[Summary of the invention]

In order to achieve the above-mentioned object, the emergency gas treatment equipment for a nuclear power plant according to the present invention is configured as follows.

In the emergency gas processing equipment of a nuclear power plant, which maintains the required negative pressure inside the reactor building by switching from the ventilation air conditioning system that ventilates and air-conditions the atmosphere inside the reactor room in the event of a reactor accident, An air supply pipe for introducing supply air into the reactor building is provided, and the air supply pipe is configured to introduce the supply air into the reactor building so that the system air volume maintains approximately the design air volume.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.

FIG. 2 is a system diagram showing an embodiment of the emergency gas treatment equipment for a nuclear power plant according to the present invention, including a nuclear reactor (not shown).
A ventilation air-conditioning system 2 that ventilates and air-conditions the atmosphere inside the reactor building 1 during normal operation, and a ventilation air-conditioning system 2 that ventilates and air-conditions the atmosphere inside the reactor building 1 during normal operation.
The emergency gas processing equipment 10 is automatically started by switching from the above.

The ventilation air conditioning system 2 includes an air supply duct 2a that introduces outside air into the reactor building 1, and an exhaust duct that exhausts the air inside the reactor building 1 to the outside air. :t=has. Air supply duct 2a
The exhaust duct 2b is connected to a supply air ladder 2c and an exhaust header 2d in the reactor building 1, and the tip openings of the branch pipes of the supply air header 2c and the exhaust header 2d are located at required locations in the reactor building 1. Open air supply duct) 2a
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at i , + 7 - ÷ The air inside the reactor building 1 that has been sucked in here is discharged to the exhaust duct 2b. The exhaust gas discharged into the exhaust duct 2b is appropriately gas-treated to remove radioactive substances, and then is discharged into the outside air through a stack (not shown).

Isolation valves 4 are provided in the air supply duct 2a and exhaust duct 2b.
, 5 are interposed respectively, and an isolation valve 4 is installed in the air supply duct 2a.
A bypass air supply pipe 1 is connected to the bypass air supply pipe 11, and an air volume adjustment valve 12 is interposed in the bypass air supply pipe 11. On the other hand, one end of an emergency exhaust duct 13 is connected to the exhaust duct 2b on the upstream side of the isolation valve 5, and the other end of this exhaust duct 1i is connected to a stack (not shown), which is equipped with a heater 14 and a filter 15 in the middle. A train 16 and an exhaust fan 17 are connected in series and connected in parallel to each other.

Therefore, if a nuclear reactor accident occurs now, both the isolation valves 4 and 5 of the supply and exhaust side ducts 2a and 2b of the ventilation air conditioning system 2
Both valves are emergency closed, and the air inside the reactor building 1 is closed. At the same time, the required number of exhaust fans 17 of the emergency gas processing equipment 10 are activated, and the air in the reactor building 1 is exhausted to the emergency exhaust duct 13 and guided to the required number of trains 16. Here, the exhaust gas is heated by the heater 14, radioactive substances are removed by the filter 15, and then released through the stack to the outside air. For this reason, the inside of the reactor building 1 becomes negative pressure. At about the same time, the air volume adjustment valve 12 of the pi-zos air supply pipe 11 is opened, and air is introduced into the reactor building 1 through the ventilation air conditioning system 2 through the bypass air supply pipe 11. The introduced air volume is set so that the system air volume in the emergency gas processing equipment 10 becomes the design air volume, and the opening degree of the air volume adjustment valve 12 is adjusted to IAI. Therefore, the actual airtightness of reactor building 1 is, for example, 30%.
/ day, 70%/day air volume bypass air supply pipe 1
The opening degree of the air volume adjustment valve 12 is adjusted so that the air is introduced into the reactor building 1 through the air flow control valve 12.

That is, the introduced air volume is set to the difference between the designed air volume in the emergency gas processing equipment 10 and the actual air tightness of the reactor building 1, and the opening degree of the air volume adjustment valve 12 is set so that the system air volume always becomes the design air volume. be adjusted. As a result, even if the system air volume remains constant and the heater 14 heats the exhaust gas at a constant temperature, a situation in which the heated dust in the system exceeds the design temperature is avoided. Therefore, there is no need to control the heating temperature of the heater 14 according to the system air volume. Emergency gas processing equipment 1o
As a result, the system air volume of reactor building 1 is maintained at the design air volume.
The degree of negative pressure inside the nuclear reactor building 10 is also maintained at a design value of, for example, -6.4 ■Aq, and the strength problems associated with excessive negative pressure in the reactor building 10 are also resolved.

FIG. 3 is a system diagram of an emergency gas processing facility according to another embodiment of the present invention, and this embodiment is provided with an emergency air supply duct 20 for introducing outside air into the reactor building 1. This emergency air supply duct) 20 is different from the embodiment shown in FIG. 2 in which air is supplied from the ventilation air conditioning system 2 into the reactor building 1. It is designed to be introduced into the reactor building 1. The emergency air supply duct) 20 is provided with an air volume adjustment valve 21, and the opening degree of this air volume adjustment valve 21 is adjusted in the same manner as in the above-described embodiment. That is, the opening degree of the air volume adjustment valve 21 is adjusted so that the system air volume in the emergency processing gas facility 10 maintains the designed air volume.

In FIG. 3, the same members as those in FIG. 2 are given the same reference numerals and their explanations are omitted.

〔Effect of the invention〕

As explained above, the emergency gas processing equipment for a nuclear power plant according to the present invention is equipped with air supply piping that introduces air into the reactor building so that the system air volume maintains the design air volume, so that the The degree of negative pressure inside the reactor building is maintained at the design value, problems with the strength of the reactor building due to excessive negative pressure are resolved, and the system air volume of the emergency gas processing equipment is always kept constant at the design air volume. Even if the heating temperature of the heater that heats the exhaust gas discharged into this system remains constant, it prevents the situation in which the temperature of the dust inside this system exceeds the design temperature. be done. Furthermore, there is no need to control the heating temperature of the heater according to the system air volume, and the system can be simplified.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a conventional emergency gas processing equipment for a nuclear power plant, Fig. 2 is a system diagram of an embodiment of an emergency gas processing equipment for a nuclear power plant according to the present invention, and Fig. 3 is a system diagram of an embodiment of the emergency gas processing equipment for a nuclear power plant according to the present invention. FIG. 2 is a system diagram of another embodiment of the emergency gas processing equipment for a nuclear power plant according to the present invention. 1... Reactor building, 2... Ventilation air conditioning system, 2a...
Supply air duct, 2b...Exhaust duct, 2C...Air supply header, 2d...Exhaust header, 3.10...Emergency gas treatment system, 4.5...Isolation valve, 6.13 ...Emergency exhaust duct, 7.17...Exhaust fan, 11...Bypass air supply pipe, 12, 21...Air volume adjustment valve, 14.
...heater, 15...filter, 16...train. Applicant's agent Hisashi Hatano

Claims (1)

[Scope of Claims] 1. Emergency gas processing for a nuclear power plant that maintains the reactor building at a required negative pressure by switching from the ventilation air conditioning system that ventilates and air-conditions the atmosphere inside the nuclear building when a nuclear reactor accident occurs. In the equipment, air supply piping is installed to introduce supply air into the reactor building in the event of a reactor accident, and supply air is introduced into the reactor building through the air supply piping so that the system air volume maintains approximately the design air volume. Emergency gas processing equipment for a nuclear power plant, characterized in that it is configured to: 2. The air supply piping is a bypass line that connects the isolation valve installed in the air supply duct of the ventilation air conditioning system of the reactor building.
The emergency gas processing equipment for a nuclear power plant according to claim 1, further comprising an air volume adjustment valve that is installed in the bypass line and adjusts the amount of air introduced. 3. The air supply piping includes an air supply pipe that directly introduces outside air into the reactor building, and an air volume adjustment valve that is interposed in the air supply pipe and adjusts the introduced air volume. emergency gas treatment equipment at a nuclear power plant.