JPS5841395A - Radioactive gas processing device - 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 a radioactive gas processing device used in a nuclear power plant.

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

The exhaust gas extracted from the condenser is placed in an attenuation pipe and an activated carbon adsorption tower, where its radioactivity is sufficiently attenuated 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. A radioactive gas processing device using a granular packing is provided for processing by a physical processing method such as UP.

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 6 is placed on the support 2.

The perforated plate 3 supports the granular filling 5 filled from the filling port 4, and also has a large number of holes 6 for gas to pass through.
is provided.

The gas enters the container 1 from the gas lower provided on the upper side of the container 1, is subjected to chemical or physical treatment in the process of passing through the granular filling 5, passes through the holes 6 of the perforated plate 6, and exits from the gas outlet 8. It flows out of container 1.

In this device, due to the delay of the filling material 5 due to deterioration, etc., the filling material 5
When it becomes necessary to replace the filling port 4, 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 the filling port 4.
Fill the container 1 with a new filling material.

In the figure, 11 is a lid for filling the filling material 5 provided at the upper end of the container 1, and 12 is a deflector plate provided at the frontage of the gas lower door.
Reference numeral 16 indicates legs that support the container 1, and 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 can fall downward.

The radioactive gas is guided from the gas introduction pipe 18 connected to the gas man lower through a U-turn around the deflector plate 12 into the five 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 device of the type shown in FIG. 2, when taking out the filling 5 for replacement etc., after removing the filling outlet cover 9,
The support plate 15 is slid to the right in the manner described above, and the granular filler 5 is dropped and taken 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.

The structure and function of two typical examples of conventional radioactive gas processing equipment using a single granular filling have been explained above.
In radioactive processing equipment with such a structure, if fragments of the granular filling fall out of the holes 6 of the perforated plate B and scattering downstream, or if the gas flow reverses, the granular packing may scatter upstream. In addition, the workability of filling and taking out the granular filling is poor, and especially when taking out the granular filling, fragments of the granular filling become dust and are likely to scatter, contaminating the environment. there were.

The present invention has been made to eliminate the above-mentioned drawbacks.
It is an object of the present invention to provide a radioactive gas processing device that prevents scattering of granular fillers and allows easy replacement of granular fillers.

That is, the present invention comprises a closely-adhered outer container having an inlet/outlet nozzle for radioactive gas, an inner container removably housed within the outer container, and a granular filler such as a catalyst or activated carbon filled in the inner container. A radioactive gas processing apparatus is characterized in that the radioactive gas is provided with a flow path through which the radioactive gas flows through the granular filling and flows out from an outlet nozzle of the external container.

An embodiment of the apparatus according to the present invention will be described below with reference to FIGS. 6 and 4.

FIG. 6 is a longitudinal sectional view showing a 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 (second side).

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 by tightening bolts 21 (thus, the support stand 19). It is supported by

A flange i:/22 is provided at the upper opening of the container 1, and a lid plate 26 is attached to this flange 22 with bolts 25 and nuts 2.
6, it has a structure that is airtight (two-fixed).

Note that 27 and 28 in the figure are gaskets for maintaining airtightness.

As shown in FIG. 4, the inner container 20 has a double structure consisting of an outer shell 29 and an inner shell 60, and a bottom plate 61 is joined to the outer shell 29. A gas flow path 20a is formed between the two and 60, and the upper part of each is connected via an upper connecting plate 32.

A bolt hole 33 and a packing groove 6 are provided at the upper edge of the outer body 29.
4, and a support 67 for supporting a cover plate 66 is provided on the inner surface of the inner shell 30.

The upper part of the outer body 29 and the cover plate 36 are provided with holes 6 for passing gas.
8 and 39 are provided, and a gap 40 is also provided between the inner shell 60 and the bottom plate 61.

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, reference numeral 41 is a hanging ear used when transporting the inner container 20 and attaching it to and detaching it from the container 1.

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

In FIG. 6, 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 68.

The radioactive gas that has flowed into the inner container 20 flows downward through the flow path 20R between the outer shell (indicated by the symbol 29 in FIG. 4) and the inner shell (indicated by the symbol 30 in FIG. 4), and flows through the gap 40. The granular filler 5 makes a U-turn and is chemically or physically treated in the process of flowing into the packed bed of the granular filler 5 and then flowing into the hole 69.
The gas flows out of the inner container 20 from the gas outlet pipe 8 to the container 1.
leak outside.

The holes 68 and 69 are provided above the granular filling 5, so that the granular filling 5 will not be discharged to the outside of the inner container 20 under normal operating conditions. This should be determined in consideration of the size of the fragments (secondarily, this can also prevent them from scattering outside the inner container 20 due to the flow of radioactive gas).

In the first embodiment shown in FIGS. 6 and 4, the inner container 2
Since the flow cross-sectional area of the gas in the 0 is larger on the downstream side than on the upstream side, the flow velocity is also slower, and in the forward direction (= when gas flows, there is not much worry of the granular filler scattering, but in case Even if the gas flows backward, scattering can be prevented by making the holes 68 sufficiently small.

In addition, when it becomes necessary to replace the granular filler 5,
After removing the bolts 25, the cover plate 26 is removed, the bolts 21 are removed, the inner container 20 is lifted up using the hanging ears 41, and then the inner container is replaced with a new one filled with granular filler.

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 one. It also has the effect of preventing environmental pollution.

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, an outer container is used instead of the first embodiment in which the inner container 20 is provided with a flange portion and fixed to a support base with bolts. The inner container 20 is placed on a support stand 19 provided below inside the container 1.
is placed on the inner container 20, and the inner container 20 is fixed by being pressed by the presser plate 42 fixed to the lid plate 26.

Further, a spacer 46 is attached to the outer surface of the inner container 20 to prevent the inner container 20 from colliding with the inner wall of the container 1 due to an earthquake or the like.

In this second embodiment, in order to maintain sealing performance by increasing the contact area between the inner container 20 and the support base 19, the inner container 20
has a concentric triple structure, and the gas to be treated is passed through the gas inlet pipe 7.
It flows through the channel 30b in the central pipe 6!1, descends from the hole 38, flows down the channel 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 69. Ru.

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 provided on the inner surface of the lid plate 26 at the mounting portion of the gas outlet 8 to prevent the granular filler 5 from entering the gas outlet 8.

When the present invention is constructed in this way, the filling can be replaced by simply attaching and detaching the lid plate 26, making the replacement work easy.

In this embodiment, the inner container 20 and the gas outlet 8 can be made so that the lid plate 26ζ is detachable.

Even if the direction of the gas flow in the first to third embodiments is reversed, there is no significant difference in the effects 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 to the granular filling is carried out through small holes through which it is difficult for fragments of the granular filling to pass through on both the upstream and downstream sides;
It is possible to prevent fragments of the granular filling from scattering due to the gas flow.

(3) Since the granular filling can be filled, taken out, and replaced with the inner container, the working time can be significantly shortened and safety can be improved. 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 the environment is not contaminated with dust.

[Brief explanation of the drawing]

1 and 2 are vertical cross-sectional views showing a conventional radioactive gas processing apparatus, FIG. 3 is a vertical cross-sectional view showing a first embodiment of the radioactive gas processing apparatus according to the present invention, and FIG. FIGS. 5 and 6 are longitudinal sectional views showing the internal container of the present invention, and FIGS. 5 and 6 are longitudinal sectional views showing second and third embodiments of the radioactive gas processing apparatus according to the present invention, respectively. 1... External container 2... Support stand 6... Perforated plate 4... Filling material filling port 5... Granular filling material 6... Hole 7... Gas inlet pipe 8
...Gas outlet 9...Filling material outlet cover 10...
Filling material outlet 11...Filling material filling mouth 12...Deflection plate 13...Legs 14...Filling material withdrawal tube 15...Support plate 16...Filling material withdrawal tube cover 17... Support 18...Gas introduction pipe 19...Support stand 20...Inner container 21...Bolt 22...Flange 2
3... Lid plate 25... Bolt 26... Nabuto 27.
...Patsukin 28...Patsukin 29...
Outer shell 30... Inner shell 31-1. Bottom plate
32... Upper connection plate 66... Bolt hole
64... Packing groove 65... Flange
66... Lid plate 37... Support 38
... Hole 69 ... Hole 40 ... Gap 41 ... Hanging ear 42 ... Holding plate 46 ...
・Subae 9 44...net (7317) Agent Patent Attorney Nori Chika Kensuke (1 idiot) Figure 1 Figure 2 Figure 3 Figure 4 Figure 31 5 A 5V

Claims (1)

[Claims] t. A sealed external container having an inlet/outlet nozzle for radioactive gas, an inner container removably housed within the outer container, and a catalyst or activated carbon filled in the inner container. A radioactive gas processing device comprising: a granular filling; and a channel through which the radioactive gas flows through the granular filling and exits from an outlet nozzle of the outer container. 2. Inside the inner container (U is characterized by being provided with an inner shell through which the radioactive gas flows in a U-turn from the top to the bottom and from the bottom to the top, and furthermore, a perforated plate is provided at the upper end. 6. The radioactive gas processing device according to claim 1. 6. The radioactive gas processing device according to claim 1, characterized in that a deflection plate is provided to cover the radioactive gas inlet nozzle hole in the external container. Radioactive gas processing equipment.