JPH01307698A - Dry storage device for atomic plant - Google Patents

Abstract

PURPOSE:To prevent the generation of corrosion and to decrease radioactive contamination by connecting a filter and gas suction device for removing dust to apparatus and piping nets which are communicated with each other and providing gas intake parts to the apparatus and piping nets, etc. CONSTITUTION:The moisture contained in the extracted air of this device is extracted and removed by a ventilation air conditioner 19 and is made again into the dry air in a turbine building 1. The inside of the apparatus and pipings is put into the dry state by the circulation of this dry air. This state is maintained during the inspection period. Corroded matter (rust) formed in the apparatus and piping nets and sticking thereto is exfoliated and pulverized and the pulverized matter splashes when the inside of the apparatus and piping nets is put into the dry state, but the splashing matter flows together with the dry air sucked from the inside of the turbine building 1 via the suction pipings 16 into a filter 17, by which said matter is captured. The cleaned air is discharged from a suction fan 18 into the turbine building 1 and the captured rust and dust are recovered and disposed after the end of the inspection. Remaining of the activated rust and dust in the apparatus and pipings is, therefore, prevented.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention is a method for rust prevention and dry storage of various equipment and piping that make up the plant during shutdown in a nuclear power plant such as a nuclear power plant. This is about @.

(Prior Art) A nuclear power plant normally shuts down its operation for about three months once a year and conducts periodic inspections. During this periodic inspection, equipment and piping that handle water, steam, air, etc. within the plant are kept in a dry or full state.

However, among these storage methods, water remains at the bottom of equipment and piping, etc., and cannot be completely removed due to their structure and arrangement, and as a result, the atmosphere inside the equipment and piping is approximately Since the equipment is in a high humidity state for a long period of three months, corrosion (rust) is likely to occur inside the equipment during this periodic inspection period. After the start of operation, this rust becomes radioactive while passing through the atom a, leading to an increase in the radioactivity concentration in the water or redeposition to the inside of the piping, leading to an increase in the radiation dose on the piping surface. This was undesirable as it led to an increase in radiation exposure for people. The degree of corrosion of metals is greatly influenced by environmental conditions, and corrosion is particularly accelerated in environments with high moisture and oxygen. Therefore, methods to reduce corrosion during storage include keeping equipment and piping in a dry state to eliminate moisture, and filling in inert gas such as nitrogen gas to eliminate oxygen. Ta.

(Problem to be solved by the invention) In order to maintain the inside of equipment and piping in a dry state, air is blown into equipment and piping using a fan, etc. When the inside dries, rust powder flies up, which causes the air to blow into the equipment and piping. It scatters into the surrounding area from the discharge openings of equipment, piping, etc. Rust in a nuclear power plant is radioactive after the start of operation, and the scattering of rust leads to deterioration of surrounding environmental conditions and an increase in radiation exposure for workers. is inappropriate. In addition, the method of sealing inert gas such as nitrogen gas can be carried out even after reactor operation has started, but during periodic inspections, there are parts of equipment and piping that are opened for inspection, so it is necessary to seal the gas. There was a problem in that the range and period in which it could be applied was limited, and the corrosion prevention effect could not be fully achieved.

An object of the present invention is to connect a gas suction device equipped with a filter for removing dust to mutually connected equipment, piping, etc., and to provide an opening in the equipment, piping, etc., so as to prevent contamination of the surrounding environment. An object of the present invention is to provide a dry storage device for a nuclear power plant that reduces the occurrence of corrosion.

[Structure of the Invention] (Means for Solving the Problems) A filter for removing dust and a gas suction device in the piping are connected to equipment and piping networks that communicate with each other, and an opening for intake of air, etc. is provided in the equipment and piping. establish.

(Function) A gas suction device sucks the surrounding air through openings in equipment and piping, etc. to dry the interior, and uses a filter to capture and collect dust that has entered the interior and rust that has formed.

(Example) An example of a turbine building according to the present invention will be described with reference to the drawings. Figure 1 is a block diagram of the main steam and water supply system including the turbine in the turbine building of a nuclear power plant, and shows the plant in operation, while Figure 2 shows the plant in Figure 1 shut down to dry equipment, piping, etc. It is a configuration diagram showing the inside.

The configuration will be explained with reference to FIG. A nuclear reactor 2, a main steam isolation valve 3, and a water supply isolation valve 4 are installed outside the turbine building 1, and are connected to a main steam pipe 5 and a water supply pipe 6 inside the turbine building 1, respectively.

Inside the turbine building 1, there is a turbine 7 and an inspection port 8a.
A double water device 8 and a double water pipe 9 equipped with a double water tank 8 and a low pressure double water pump 10 connected thereto. Double water purifier 11, high pressure double water pump 1
2 and 2 feed water heaters 13 are installed, and are further connected to the water feed pipe 6 via a water feed pump 14. In addition, a filter 17 for capturing rust and dust and a suction fan 18 connected to the filter 17 are installed between the condenser 8 and the low pressure pump 10, between the double water purifier 11 and the high pressure double water pump 12, and between the water supply. One end of a suction pipe 16 with an on-off valve 15 inserted is connected between the heater 13 and the water supply pump 14, and the other end is connected to the filter 11. Additionally, a ventilation air conditioner 19 is installed inside the turbine building 1. During operation, the inspection port 8a of the condenser 8 and the on-off valve 15 are kept closed.

Next, the operation of the above configuration will be described with reference to FIG.

During regular inspections, the area between reactor 2 and turbine building 1, which was shut down, was
The main steam isolation valve 2 and the feed water isolation valve 4 are closed and shut off. In the turbine building 1, after removing the steam and water supply inside the main steam system and water supply system equipment and piping, check the inspection windows and stopcocks of various types of separators and piping, such as the inspection port 8a of the condenser 8. etc. (opening 20), and conducts each inspection. At this time, as a drying device, the on-off valve 15 is opened and the suction fan 18 is operated. As a result, dry air whose temperature and humidity have been constantly purified and whose temperature and humidity have been adjusted by the ventilation air conditioner 19 in the turbine building 1 is sucked in through the inspection port 88, which is the opening 20 opened for each of the above-mentioned inspections, as shown by the arrows. The suction pipe 16 is connected to the double water pipe 9 and the water supply pump 14.
and a water supply pipe 6 via this, and a high-pressure double water pump 12
and two feed water heaters 13, a double water purifier 11, a low pressure double water pump 10, a turbine 7 and a main steam pipe 5 via a condenser 8, etc., and equipment and piping networks that are connected to each other. The residual moisture inside is vaporized and discharged into the turbine building 1 through the suction fan 18. Moisture contained in this discharged air is extracted and removed by the ventilation air conditioner 19 within the turbine building 1 and becomes dry air again. Through the circulation of this dry air, the inside of the equipment, piping, etc. becomes dry, and this state is maintained during the inspection period. Next, when the inside of the equipment and piping network becomes dry, the corrosive matter (rust) that has formed and adhered therein peels off, becomes fine powder, and scatters. It reaches the filter 17 and is captured.

Further, the air purified by the filter 17 is discharged into the turbine building 1 from the suction fan 18, and the rust and dust captured by the filter 17 are collected and disposed of after the inspection is completed.

Therefore, the rust and dust that have been exposed to radiation will not remain in separate containers or inside the piping, and will not contaminate the surrounding environment.

Even if this dry storage device is used in equipment or piping that handles gases such as air, it is possible to remove moisture, dust, etc. that enter the device along with the circulating gas and separate inside, as in the previous embodiment. Of course.

[Effects of the Invention] According to the present invention, when a nuclear power plant is shut down for inspection, the interior of separate vessels and piping can be kept in a dry state without interfering with the inspection work, thereby preventing the occurrence of corrosion. At the same time as preventing radioactive contamination of equipment and its surrounding environment, it also reduces radioactive contamination of equipment and its surrounding environment. It also has the effect of reducing ffi.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, which is a block diagram of the main steam and water supply system inside the turbine building of a nuclear power plant, showing the plant during operation, and FIG. 2 shows the plant shown in FIG.
It is a block diagram which shows piping etc. in dry storage. 1...Turbine building 5...Main steam piping 6...
Water supply piping 7...Turbine 8...Double water device
8a...Inspection port 9...Double water piping 10
...Low pressure double water pump 11...Double water purifier 12...High pressure double water pump

Claims (1)

[Claims] In equipment and piping installed in nuclear power plants,
1. A dry storage device for a nuclear power plant, characterized in that a filter for removing dust and a gas suction device are connected to equipment and piping networks that communicate with each other, and a gas intake section is provided in the equipment, piping, etc.