JPH0136599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radioactive gas processing device used in a nuclear power plant.

Radioactive gaseous waste generated at nuclear power plants is mainly exhaust gas extracted from turbine condensers, and includes radioactive noble gases and gaseous fission products from the nuclear reactor.

The exhaust gas extracted from the condenser is passed through an attenuation pipe and an activated carbon adsorption tower to sufficiently attenuate its radioactivity before being diffused into the atmosphere.

By the way, in nuclear power plants, combustible substances, radioactive particles, radioactive noble gases, etc. contained in radioactive gases such as radioactive gaseous waste are removed through chemical reactions using catalysts, filtration using sand, etc., adsorption or holding using activated carbon, etc. For processing using physical processing methods such as
A radioactive gas treatment device using granular packing is provided.

FIG. 1 is an example of a gas processing device used in a conventional plant.

That is, in the apparatus shown in FIG. 1, a support 2 is fixed to the inner surface of the container 1, and a perforated plate 3 is placed on the support 2.

The porous plate 3 supports the granular filler 5 filled from the filler port 4, and is provided with a large number of holes 6 so that gas can pass therethrough.

The exhaust gas is passed through the gas inlet 7 provided on the upper side of the container 1.
The gas enters the container 1 through the granular filler 5, undergoes chemical or physical treatment, and flows out of the container 1 through the gas outlet 8 through the holes 6 of the perforated plate 3.

In this device, due to the deterioration of the filling material 5, etc.
When it becomes necessary to replace the filling 5, remove the filling outlet cover 9 provided on the side of the container 1, take out the granular filling 5 from the filling outlet 10, and then replace it from the filling opening 4. Fill container 1 with new filling.

In the figure, 11 indicates a lid for filling the filler 5 provided at the upper end of the container 1, 12 indicates a deflector plate provided at the frontage of the gas inlet 7, and 13 indicates legs supporting the container 1.
Further, arrows indicate the flow of gas.

FIG. 2 is a longitudinal cross-sectional view showing another example of a radioactive gas processing apparatus using a granular filling 5. The granular filling 5 filled in the container 1 is connected at right angles to the filling outlet 10. It is supported by a support plate 15 inserted into the filled material drawing pipe 14.

The end of the support plate 15 is fixed to the filling material extraction tube lid 16, and by pulling the filling material extraction tube lid 16 to the right in the figure, it slides to the right on the support 17, and the granular filling 5 It is designed so that it can fall downward.

The radioactive gas is guided from the gas introduction pipe 18 connected to the gas inlet 7 through the deflection plate 12 through a U-turn into the 5 layers of granular packing filled in the container 1, and is treated in the process of passing through the granular packing 5. The gas flows out from the gas outlet 8.

In the apparatus of the type shown in FIG. 2, when taking out the filling 5 for replacement etc., after removing the filling outlet cover 9, slide the support plate 15 to the right as described above, and remove the granular filling 5. Let it fall and take it out.

Note that the names and functions of components not explained in the drawings are the same as those of the device shown in FIG. 1.

Above, we have explained the structure and function of two typical examples of conventional radioactive gas processing equipment using granular packing. If the granular filler falls out of the hole 6 and scatters downstream, or if the gas flow reverses, the granular filling may scatter upstream, causing adverse effects such as abnormalities in the equipment and surrounding systems. There is a drawback that it causes Moreover, the workability of filling and taking out the granular filler is poor, and especially when taking out the granular filler, fragments of the granular filler become dust and are likely to scatter, contaminating the environment.

The present invention was made in order to eliminate the above-mentioned drawbacks, and an object of the present invention is to provide a radioactive gas processing device that prevents scattering of granular fillers and improves safety by allowing easy replacement of granular fillers. be.

That is, the present invention provides an outer container having an inlet/outlet nozzle for a radioactive gas, and an inner container having an inlet/outlet hole for the radioactive gas that is detachably housed in the outer container and inserted into the outer container from the inlet nozzle. and a granular filling filled in the inner container, in which an inlet/outlet hole provided in the inner container is located above the granular filling, and a top surface of the inner container has a This is a radioactive gas processing device characterized by being provided with a perforated plate.

An embodiment of the apparatus according to the present invention will be described below with reference to FIGS. 3 and 4.

FIG. 3 is a longitudinal sectional view showing the first embodiment of the radioactive gas processing apparatus according to the present invention.

A gas inlet pipe 7 is provided on the lower side of the container 1, and a gas outlet pipe 8 is provided on the upper side, and a baffle plate 12 is fixed to the inner surface of the container 1 near the gas inlet pipe 7.

Further, a support stand 19 is provided on the upper inner surface of the container 1, and an inner container 20 having a double cylindrical structure filled with the granular filler 5 is suspended from the support stand 19 by tightening bolts 21. Supported.

A flange 22 is provided at the upper end opening of the container 1, and a lid plate 23 is attached to the flange 22 with bolts 2.
5. It has a structure that is airtightly fixed with a nut 26.

In addition, 27 and 28 in the figure are gaskets for maintaining airtightness.

The inner container 20 has an outer shell 2 as shown in FIG.
9 and an inner shell 30, a bottom plate 31 is joined to the outer shell 29, and a gas passage 20a is formed between the outer shell 29 and the inner shell 30. The upper portions of each are connected via an upper connecting plate 32.

A flange 35 having a bolt hole 33 and a packing groove 34 is provided on the upper edge of the outer shell 29, and a support 37 for supporting a cover plate 36 made of a perforated plate is provided on the inner surface of the inner shell 30.

Holes 38 and 39 for passing gas are provided in the upper part of the outer shell 29 and the lid plate 36 above the granular filling 5, and a gap 40 is also provided between the inner shell 30 and the bottom plate 31. There is.

The granular filler 5 is contained in the inner shell 30, but a small amount enters into the outer shell through the gap 40.

Incidentally, the reference numeral 41 carries the inner container 20 and the container 1.
These are the hanging ears used when attaching and detaching.

Next, the operation of the first embodiment will be explained.

In FIG. 3, the radioactive gas flowing into the outer container 1 from the gas inlet pipe 7 is diffused into the outer container 1 by the baffle plate 12 and flows into the inner container 20 through the hole 38.

The radioactive gas that has flowed into the inner container 20 flows downward through the flow path 20a between the outer shell (indicated by 29 in FIG. 4) and the inner shell (indicated by 30 in FIG. 4), and passes through the gap 40. It makes a U-turn and flows into the packed bed of the granular filler 5, is subjected to chemical or physical treatment in the upward process, and then flows out of the inner container 20 through the hole 39 and into the container from the gas outlet pipe 8. 1 to flow outside.

Since the holes 38 and 39 are provided above the granular filler 5, the granular filler 5 will not be discharged outside the inner container 20 under normal operating conditions due to the action of gravity of the granular filler, and the holes 38 and 39 38, 39
By determining the diameter in consideration of the size of the fragments of the granular filling, it is possible to prevent the radioactive gas from scattering outside the inner container 20 due to the flow of the radioactive gas.

In the first embodiment shown in FIGS. 3 and 4, the cross-sectional area of the gas flow path in the inner container 20 is larger on the downstream side than on the upstream side, so the flow velocity is also slower, and the gas flows in the forward direction. When the gas flows, there is little concern that the granular filler will scatter, but even if the gas should flow back, scattering can be prevented by making the holes 38 sufficiently small.

In addition, when it becomes necessary to replace the granular filling 5, remove the bolts 25, remove the cover plate 23, remove the bolts 21, lift the inner container 20 using the hanging ears 41, and then replace it with a new one. Replace with inner container filled with granular filling.

In this replacement work, there is no need to take out or fill the granular filling directly, and the work can be done in a short time, so the safety of the work is significantly improved compared to the conventional method.In addition, the dust from the granular filling does not cause environmental pollution. It also has the effect of preventing

FIG. 5 is a longitudinal sectional view showing a second embodiment of the radioactive gas processing apparatus according to the present invention.

In this second embodiment, in order to make it easier to attach and detach the inner container 20 to and from the container 1, the inner container 20 is provided with a flange portion and fixed to a support base with bolts.
Instead of the embodiment described above, the inner container 20 is placed on a support base 19 provided below inside the outer container 1, and the inner container 20 is fixed by being pressed by a presser plate 42 fixed to the lid plate 23.

Further, a spacer 43 is provided on the outer surface of the inner container 20.
When the inner container 20 is damaged due to an earthquake etc.
This prevents it from colliding with the inner wall.

In this second embodiment, an inner container 20 and a support base 1 are used.
In order to increase the contact area with 9 and maintain sealing performance, the inner container 20 has a concentric triple structure, and the gas to be treated flows from the gas inlet pipe 7 through the flow path 30b in the central pipe 3a, and descends from the hole 38. It flows down the flow path 30c, makes a U-turn from the lower end of the inner shell 30, flows into the filling 5, and is discharged from the hole 39.

FIG. 6 is a longitudinal sectional view showing a third embodiment of the radioactive gas processing apparatus according to the present invention, in which the inner container 20 is integrally constructed with a cover plate 23, and the gas outlet 8 is provided on the cover plate 23. ing.

A mesh 44 is attached to the gas outlet 8 mounting part on the inner surface of the lid plate 23.
is provided to prevent the particulate filling 5 from entering the gas outlet 8.

When the present invention is configured in this way, the filling can be replaced by simply attaching and detaching the lid plate 23, making the replacement work even easier.

In this embodiment, the inner container 20 and the gas outlet 8 can be detachably attached to the lid plate 23.

Even if the direction of gas flow in the first to third embodiments is reversed, there is no significant difference in the effect of the present invention.

The radioactive gas processing apparatus according to the present invention described above has the following effects.

(1) The ventilation holes of the inner container filled with granular filling can be placed above the filling height of the granular filling on both the upstream and downstream sides, so that fragments of the granular filling can spill into the container and cause damage to the upstream or downstream side. This prevents it from scattering to the side and adversely affecting the system.

(2) Ventilation of the granular filling is carried out through small holes on both the upstream and downstream sides through which the fragments of the granular filling are difficult to pass through, so it is possible to prevent the fragments of the granular filling from scattering due to the gas flow.

(3) Filling, taking out, and replacing the granular filling can be done in the inner container, which greatly reduces work time and improves safety. Moreover, transportation becomes easier.

(4) When filling, taking out, and replacing the granular filling, the granular filling itself remains stored in the inner container, so that dust does not contaminate the environment.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional views showing a conventional radioactive gas processing apparatus, FIG. 3 is a longitudinal cross-sectional view showing a first embodiment of the radioactive gas processing apparatus according to the present invention, and FIG.
This figure is a longitudinal sectional view showing the inner container of FIG. 3, and FIGS. 5 and 6 are longitudinal sectional views showing the second and third embodiments of the radioactive gas processing apparatus according to the present invention, respectively. DESCRIPTION OF SYMBOLS 1... External container, 2... Support stand, 3... Porous plate, 4... Filler filling port, 5... Granular filler, 6
...hole, 7...gas inlet pipe, 8...gas outlet, 9
...Filling material outlet cover, 10...Filling material outlet, 1
1... Filling palate, 12... Deflector plate, 13
...Legs, 14...Filling material extraction tube, 15...Support plate, 16...Filling material extraction tube lid, 17...Supporting tool,
18...Gas introduction pipe, 19...Support stand, 20...
Inner container, 21... bolt, 22... flange,
23...Lid plate, 25...Bolt, 26...Nut, 27...Putskin, 28...Putskin, 29
...Outer body, 30...Inner body, 31...Bottom plate, 32...
... Upper connection plate, 33 ... Bolt hole, 34 ... Packing groove, 35 ... Flange, 36 ... Lid plate, 37
...Support, 38...hole, 39...hole, 40...
Gap, 41...Hanging ear, 42...Press plate, 43...
Spacer, 44...net.

Claims (1)

[Claims] 1. A covered external container having an inlet nozzle and an outlet nozzle for radioactive gas; an inlet hole that is removably housed in the outer container and into which the radioactive gas introduced from the inlet nozzle into the outer container flows; In a radioactive gas processing device comprising an inner container having an outlet hole for flowing out, and a granular filling filled in the inner container, the inner container includes an outer shell which is a cylindrical container with a bottom, and an inner part of the outer shell. The granular filling is filled in the inner shell, and the upper part of the inner shell has a lid. An inlet hole and an outlet hole of the inner container are located at a height above the granular filling and are bored in the side wall of the outer shell and the cover plate of the inner shell, respectively, and the inlet hole and the outlet hole of the inner container are perforated in the side wall of the outer shell and the lid plate of the inner shell, respectively. The radioactive gas flowing into the inner shell descends on the outside of the inner shell, flows into the inner shell through the gap, turns into an upward flow, and flows out through the outlet hole through the granular filling. 1. A radioactive gas processing device characterized in that the outlet hole is composed of a large number of small holes.