JPS6123999A - Exhaust facility for disusing work of nucler reactor - 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] The present invention relates to exhaust equipment for decommissioning a nuclear reactor.

There is no previous experience in nuclear reactor decommissioning work, and therefore, in order to carry out this decommissioning work safely, it is necessary to configure work equipment from a new perspective. In particular, when thermally cutting activated biological shielding concrete, it is necessary to minimize the radiation exposure of workers due to the generation of radioactive dust and to effectively remove the heat generated during thermal cutting. . Furthermore, the government must also prevent the surrounding environment from being polluted as a result of this decommissioning work.

The present invention aims to provide exhaust equipment for nuclear reactor decommissioning work that satisfies these requirements at the same time.

That is, as shown in FIG. 1, the present invention is a facility for effectively achieving the above object, in which the decommissioning work area of a nuclear reactor is isolated from the surrounding atmosphere by an airtight material to form a closed space 1. This exhaust equipment is used when decommissioning work involving thermal cutting is carried out by incorporating a dismantling device driven by remote control into the closed space 1, and the exhaust passage 2 leads from the inside of the closed space 1 to the outside. and dust collection device 3
A blower 4 is interposed in this exhaust passage 2 to form a return air passage 5 that branches from the exhaust passage 2 located downstream of the dust collector 3 and the blower 4 and communicates with the closed space 1. An air cooler 6 is interposed in the air passage 5, an air purifier 7 and a control valve 8 for controlling the exhaust/return air quantity ratio are interposed in the exhaust passage 2a downstream of the branch position, and the other , an air supply path 9 for supplying fresh air to the closed space 1
At the same time, a supply air purification device 10 and a control valve 11 for adjusting the supply air amount are interposed in the supply air passage 9, and by adjusting the control valves 8 and 11, the inside of the closed space 1 is made more negative than the surrounding environment. The present invention provides exhaust equipment for decommissioning a nuclear reactor, which is characterized in that the exhaust pressure is maintained at a constant pressure.

Each device of the equipment of the present invention and their positional relationship will be explained in detail below.

In FIG. 1, reference numeral 1 denotes a closed space that encloses the decommissioning work area. is formed. The airtight material 21 is made of a material that is gas-impermeable, thereby forming a secondary enclosure.

Decommissioning work will be carried out within this closed space 1, and this work will be carried out using unmanned machines driven by remote control. Reference numeral 22 indicates an unmanned cutting machine that performs the cutting process. This cutting machine 22
is the main shaft 23 inserted into this closed space 1.
Therefore, it is supported so as to be able to slide up and down, and can be controlled by remote control to perform up and down movement, one circular movement, nine swing movements, telescopic movement, and other movements necessary for cutting at various positions. For this cutting process, in addition to mechanical cutting process, thermal cutting process using, for example, thermal spraying of high-temperature gas can be applied in the equipment of the present invention. In addition to the cutting machine, other machines necessary for demolition are also operated by remote control.

The exhaust passageway 2 is an airway that exhausts air containing radioactive dust within the closed space 1 to the outside. This exhaust passage 2 is 5
In principle, it refers to a path leading from the suction ports provided at various locations in the closed space 1 to the exhaust pipe 24, but there is a branch point 25 in the middle of the path, and a return air path 5 returns from this branch point 25 to the closed space 1. It is divided into an exhaust passage 2a leading to an exhaust pipe 24. The exhaust passage 2 from the closed space 1 to the branch point 25 is an air supply path 1β that takes out exhaust air from each of suction ports 12, 26, 27, etc. provided at various locations in the closed space 1.

28, 29 and these air passages 13.28.29
Main exhaust passage 2 that collects and sends the exhaust gas sent through
It is divided into part b.

A dust collector 3 and a blower 4 are interposed in the main exhaust passage 2b. Dust collector 3 is a bald filter-type dust collector, and the filter that has become clogged with dust is backwashed and cleaned with high-pressure air, and the attached dust is collected by falling downward through a rotary valve. is,
The waste is stored in the waste storage tram 30. This drum 30 is installed on a weight measuring device, and when the weight reaches a preset value, it is replaced with an empty container while still being sealed.

In the illustrated example, a branch point 25 is provided on the discharge side of the blower 4, and the air outlet 3 of the closed space 1 is connected to the branch point 25.
1 is formed.

An orifice 32 and an air cooler 6 are installed in this return air passage 5. The air cooler 6 consists of a cooling coil through which refrigerant or cold water flows, and a part of the air from which dust has been removed by the dust collector 3 is cooled here and then returned to the closed space 1. The orifice 132 serves as a resistance to guide only a portion of the total exhaust gas to the return air path 5, and a decompression effect to effectively cool the air in the air cooler 6.

An air purifier 7 and a control valve 8 are installed in the exhaust passage 2a from the branch point 25 to the exhaust pipe 24. This control valve 8
is an automatic control valve. The air purifying device 7 has a built-in HEPA filter 33, which collects fine particles that cannot be collected by the dust collector 3 with high efficiency.

The automatic control valve 8 is for controlling the displacement/return air amount ratio, and by adjusting the automatic control valve 8, the amount of returned air can be controlled.

A remote manual adjustment valve 35.36.37 is installed in each air supply path 13.28.29 that sends out exhaust air from each suction port 12.26.27, etc., and these allow each suction port 12.26. You can adjust the amount of suction from .27. At this time, at least one of the suction ports is configured to be able to suck in air near the cutting machine 22 during one operation.

The suction port should be movable. That is, in the example shown in Figure 1, the suction port 12 consists of a hood that is supported by the main shaft 23 so as to be movable up and down. Inhale the generated dust at its source. The movement of this hood, along with the cutting process, is performed by remote control monitored by a television camera. The hood 12 is connected to the air supply path 13 by a flexible duct 38 via a winder 39 .

A cyclone 14 is attached to this air supply path 13 to primarily collect dust. The dust collected here can also be taken out of the machine while being sealed, as in the case of the dust collector 3 mentioned above.

A system separate from the exhaust system configured in this way is used for the closed space 1.
Fresh outside air is supplied from the air supply path 9.

A supply air purifying device 10 and a control valve 11 for adjusting the supply air amount are attached to the supply air passage 9. This control valve 11 is a remote manual adjustment valve. The supply air purification device 10 has a filter built therein.

On the other hand, a preliminary exhaust passage 40 is provided for controlling the exhaust amount in an emergency or during non-working hours such as at night or on holidays. This is an air passage leading from the suction port 41 of the closed space 1 to the exhaust pipe 24, and the blower 42. Air purification device 43. A cyclone 44, an automatic control valve 45, and the like are installed in this air passage. This makes it possible to sufficiently remove dust and control the pressure inside the closed space 1 even in an emergency.

According to the equipment of the present invention having the above configuration, decommissioning work can be carried out in the closed space 1, which is always controlled to have a lower pressure than the surrounding atmosphere, and the heat and dust generated inside the space can be safely removed from the system. It becomes possible to take it out. In other words, negative pressure control can be easily performed by adjusting the differential pressure regulator (DPCI), automatic control valve 8, and remote manual control valve 11, thereby preventing air in the closed space 1 from leaking out of the system. At the same time, by introducing fresh outside air and cooling the circulating air, the heat generated within the closed space 1 is effectively taken out of the system and cooled, thereby making it possible to prevent heat from accumulating inside.

Even if the dust contains radioactivity, it can be removed from the system without being dissipated into the outside air.

[Brief explanation of the drawing]

FIG. 1 is an equipment layout system diagram of the equipment of the present invention. 1. Shield space, 2. Exhaust passage, 3. Dust collection device, 4. Blower, 5. Air passage. 6. Air cooler, 7. Air purification device. 8. Automatic control valve, 9. Air supply path, 10. Air supply purification device, 11. Control valve (remote manual adjustment valve). 12...Movable suction port (hood), 21...Airtight material, 22...Cutting machine, 23...Main shaft. Applicant Takasago Thermal Engineering Co., Ltd. Kumagai Gumi Co., Ltd.

Claims (2)

[Claims] (1) The decommissioning work area of the nuclear reactor is isolated from the surrounding atmosphere by airtight material to form a closed space 1, and this closed space 1 is
This exhaust equipment for decommissioning a nuclear reactor incorporates a dismantling device driven by remote control inside the closed space 1, which forms an exhaust passage 2 leading from the inside of the closed space 1 to the outside, and also has a dust collection device 3.
A blower 4 is interposed in this exhaust passage 2 to form a return air passage 5 that branches from the exhaust passage 2 located downstream of the dust collector 3 and the blower 4 and communicates with the closed space 1. An air cooler 6 is interposed in the air passage 5, an air purifier 7 and a control valve 8 for controlling the exhaust/return air quantity ratio are interposed in the exhaust passage 2a downstream of the branch position, and the other , an air supply path 9 for supplying fresh air to the closed space 1
At the same time, a supply air purification device 10 and a control valve 11 for adjusting the supply air amount are interposed in the supply air passage 9, and by adjusting the control valves 8 and 11, the inside of the closed space 1 is made more negative than the surrounding environment. Exhaust equipment for nuclear reactor decommissioning work that maintains pressure. (2) The exhaust passage 2 is connected to a plurality of suction ports provided in the closed space 1, and at least one of the suction ports is a mobile suction port 12 that sucks air near the decommissioning work area; The exhaust equipment for decommissioning a nuclear reactor according to claim 1, wherein a cyclone 14 is interposed in an air passage 13 leading from the mobile suction port 12 to the exhaust passage 2.