JPS5837520B2 - pollution dust prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contaminated dust prevention device used during periodic inspection work of a nuclear power plant.

As shown in Fig. 1, the refueling exchange floor of the reactor building in a conventional nuclear power plant includes a spent refueling pool 1 with a cask storage area 2, a refueling exchange boule 3 with a service box 8, and a drain rotor. A dryer and separator temporary pool 4 having a service box 9 and a dryer 5 are buried in a concrete frame (not shown).

A steam separator 6 and a steam dryer 7 are transported and stored in the temporary boule 4 by a crane (not shown).

At nuclear power plants, power generation equipment, including the above equipment, is periodically inspected from the viewpoint of maintenance.This periodic inspection is required by related laws and regulations such as the Electricity Business Act and the Regulations for Enforcement of the Electricity Business Act. The timing of periodic inspections and target equipment are stipulated.

However, regular inspections of nuclear power plant equipment require maintenance and inspection work to be completed while being exposed to radioactive materials, so this work must be completed extremely quickly.

In addition, in the maintenance and inspection work of nuclear power generation equipment, special tools for periodic inspections are used for various types of equipment, and inspectors are trained, which has been effective. There is a limit to this, and once a certain range is reached, it becomes almost impossible to shorten the period of periodic inspections, and there is a risk that it will not be possible to reduce the amount of radioactivity that inspection workers are exposed to.

The present invention aims to eliminate the above-mentioned drawbacks and ensure the safety of inspection workers. Radioactive substances are scattered into the surrounding environment from radioactively contaminated equipment and piping that are dismantled during maintenance inspections. Provide a spray device to prevent
This spray device is characterized in that the liquid is sprayed onto the locations where the equipment, piping, etc. are located.

An embodiment of the present invention will be described below with reference to the drawings.

We will only discuss the differences between this embodiment, that is, the reactor building fuel control exchange floor shown in FIGS. 2 to 5, from the conventional one.
A suction duct 12 having a suction port 13 is provided on each inner wall surface 17 of the firestick exchange boule 3, the dryer, and the separator temporary pool 4 (hereinafter referred to as temporary pool). A spray pipe 10 having a diameter of 11 is installed.

This piping 10 is connected to a hose 21 having a decontamination water source valve 19 via a quick joint 20, and the decontamination water source valve 19 is housed in service boxes 8 and 9.

In addition, 14 and 15 are the reactor containment vessel and reactor pressure vessel installed in the fuel exchange pool 3, 16 is the fuel exchange boules 3, and 22 is the spent fuel pool 1 and the fuel exchange pool. 3 and a temporary pool 4 are buried therein.

When carrying out periodic inspections, the hatch 16 of the fuel exchange pool 3 is
The reactor containment vessel 14 and the reactor pressure vessel 15 are sequentially disassembled.

Next, the steam separator 6 and the steam dryer 7 are taken out from the pressure vessel 15 by the crane κ and transported to the temporary boule 4K.

After completing such preparations, the κ periodic inspection work will begin.

At the same time as this work begins, air purification work will be carried out on the fire pit replacement floor using ventilation air conditioning equipment.

In this case, conventionally, as the steam separator 6, steam dryer 7, and other furnace internal structures were dried, the fine contaminants that had adhered to them became contaminated dust, which was scattered in the periodic inspection work area and inside the inspection worker's body. There was a risk of triggering an atomic bombing.

However, in the present invention, during periodic inspection work, the decontamination water source valve 1
9 and spray the decontamination water from the mist spray nozzle 11.
8 periodically on the inner wall of the fuel stamp exchange pool 3 and the temporary storage pool 4,
Since the steam separator 6 and the steam dryer 7 are injected to keep the radioactively contaminated duct that adheres to them wet at all times, the amount of radioactive radiation that inspection workers are exposed to from the contaminated duct κ is reduced, and safety is ensured. You can improve your sexual performance.

Furthermore, according to this embodiment, even if a part of the radioactively contaminated duct that has not been wetted by the periodically sprayed spray 18 is scattered, the radioactively contaminated duct will not be affected by the installation of the spray pipe 10. Since the liquid is sucked through the suction port 13 of the suction duct 12, inspection work can be performed even more safely.

As explained above, according to the present invention, it is possible to prevent the scattering of radioactively contaminated dust, reduce the amount of radioactive radiation in the body of an inspection worker, and improve the safety of periodic inspections.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a conventional reactor building refueling floor, and FIGS. 2 and 3 are a plan view and a longitudinal section of a reactor building fuel exchange floor showing an embodiment of the contaminated dust prevention device of the present invention. figure,
Figures 4 and 5 are the lines IV-IV and V- of Figure 2.
It is a sectional view taken along the v line. Explanation of the symbols, 3... Fuel exchange pool, 4... Dryer, separator temporary pool, 6... Steam separator, 7... Steam dryer, 10... Spray arrangement! , 11...Subray nozzle 17...Inner wall.

Claims (1)

[Claims] 1 A device installed on the side wall surface of a pool for storing radioactive substances and spraying decontaminated water to prevent scattering of radioactive contaminated dust, wherein the contaminated dust prevention device is installed along the side wall surface of the pool. A device for preventing radioactive contamination dust, comprising a suction duct for suctioning scattered contamination dust, and a spray device provided on the outer peripheral surface of the suction duct.