JPS6020199A - Device for fixing radioactive gas - 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 [Technical Field of the Invention] The present invention relates to a radioactive gas immobilization device for immobilizing a radioactive gas such as krypton.

[Technical Background of the Invention] Of the radioactive gaseous wastes generated in nuclear power facilities such as nuclear power generation plan 1~ and nuclear fuel reprocessing plants, Kr-8 in particular
5 has a relatively long half-life of 10.6 years, and if released into the atmosphere as is, it could lead to global environmental pollution.

Therefore, there is a need for a technology to reliably store radioactive waste such as Kr-85, and currently, methods such as high-pressure cylinder storage, zeolite adsorption, and immobilization using ion injection methods have been developed or are under development.

Figure 1 does not show a conventional radioactive gas immobilization device using the ion implantation method. Kr-85 is introduced through the introduction tube 4. The closed container is maintained at a constant low pressure lC by a vacuum pump (not shown) connected to the suction tube 5.

A voltage is applied between the outer cylinder 1 and the inner cylinder 2 by an external power supply 6.

In such a radioactive gas fixation device, when the pressure inside the sealed container and the voltage applied between the outer cylinder 1 and the inner cylinder 2 meet appropriate conditions, electric discharge can occur throughout the sealed container. J, well known as c13, this discharge causes Kr
-85 becomes an ionized state.

When the inner cylinder 2 is grounded and the outer cylinder 1 is set to a negative voltage by the power source 6, Kr-85 ions 7 ionized by discharge
are accelerated along the electric field and collide with the inner surface of the outer cylinder 1, and as a result, the Kr-85 ions 7 are injected into the outer cylinder 1 and fixed. When a certain amount of L(r-85) is injected into the outer cylinder 1, a saturation phenomenon occurs, and the injected Kr-85fft and the re-released Kr-85 amount become the same value, so before reaching saturation, Then, the polarity of the power source 6 is reversed, the outer cylinder 1 is grounded, and the inner cylinder 2 is set to a negative voltage.As a result, the Kr-85 ions 7 are accelerated toward the inner cylinder 2 and collide with them.

When Kr-85 ions collide with the inner cylinder 2, the inner cylinder 2
A so-called sputtering occurs in which the metal is ejected into the container in a neutral state, and as a result, the ejected metal is stacked on the inner surface of the opposing outer cylinder 1. After the metal of the inner cylinder 2 is sufficiently formed into m layers on the inner surface of the outer cylinder 1 by sputtering,
By reversing the polarity of the power source 6 again, l(r-85 is injected into the inner surface of the outer cylinder 1. By repeating this process, Kr-85 is injected into the inner surface of the outer cylinder 1 multiple times.

In addition, we decided to set the voltage applied between the inner cylinder 2 and the outer cylinder 1 and the repetition period of the application to appropriate conditions. Kr-85 can only be injected into.

Storage after injection of Kr-85 is carried out by removing M3 from outer cylinder 1, pulling out inner cylinder 2, and instead attaching the cylindrical member to outer cylinder 1 and storing it as it is.

[Problems with blue technology] However, in the conventional radioactive gas immobilization device using such an ion implantation method, Kl'-8 is added to the inner surface of the outer cylinder 1.
5, the Kr-85 injection volume is relatively small compared to the volume occupied by the entire radioactive gas immobilization charge, and during storage, the outside of the Kr-85 is stored as a cavity, requiring less space for storage. The problem is that it is very wide.

[Object of the Invention] The present invention has been made in response to such conventional circumstances,
It is an object of the present invention to provide a radioactive gas immobilization device that can efficiently immobilize radioactive gas and whose storage volume can be significantly reduced compared to conventional ones.

[Summary of the Invention] The present invention provides a plurality of plate-shaped electrodes arranged at regular intervals in a closed container, and applying opposite voltages to adjacent electrodes among these electrodes. A radioactive gas immobilization device comprising: an application device for applying voltage, a radioactive gas supply device for supplying radioactive gas into the sealed container, and a pressure reducing device for reducing the pressure inside the sealed container. It is.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail as shown in the drawings.

FIG. 2 shows a radioactive gas fixing device according to an embodiment of the present invention. In this radioactive gas fixing device, injection electrodes 11a, 11b, . 12a, 12b...
・ are each formed into a flat plate shape, and are arranged opposite to each other at equal intervals.

The injection electrodes 11a, 11b... are each connected to a lead wire 16.
The sputtering electric currents t412a, 12b, . . . are connected to the lead wires 17, respectively. The lead wires 16 and 17 are the leads of the shell 14, which are placed in the container 13 containing the single electrodes 11a, 11b... and the sputtering electrodes 12a, 121)... It is externally connected to a power source 6 via a wire outlet.

In order to set the pressure of the container 13 to a pressure condition that easily causes discharge, a vacuum pump connected to the suction pipe 55 of the pressure reducing device is used.
(not shown), Kr-85 is introduced from the introduction pipe 4 of the radioactive gas supply device, and maintained at a constant pressure.

In the radioactive gas fixation device configured as described above, the external power supply 6 maintains the injection electrodes 118, 11b, . The injection electrodes 11a111b...
... is injected into...

Then, Kr − to the injection electrodes 11a, 1111...
Before the Kr-85 ion implantation reaches saturation, the polarity of the power supply 6 is reversed, and the Kr-85 ions are transferred to the sputtering electrodes 12a, i2b.
By colliding with..., the sputtering electrodes 12a, 1
Neutral metal released from 211... is injected into the electrode 11
It is laminated on the surface of a111b.... Note that injection of Kr-85 into the sputter electrodes 12a, 12b, . . . is prevented by adjusting the applied voltage of the power source 6 and adjusting the polarity inversion period.

In the radioactive gas fixing device configured as described above, the flat injection electrodes 11a, 11b... and the sputtering electrodes 12a, 12b... have their lead wires 16, 17 cut off after Kr-85 is injected. Then, as shown in FIG. 3, they are stacked alternately and placed in a storage container 23, and then sealed with a lid 24. The d3 enclosure is performed, for example, by welding the peripheries of the storage container 23 and the lid 24.

Therefore, the injection electrodes 11a, 11b...
and the sputtering electrodes 12a, 1211, etc., making it possible to significantly reduce the storage volume compared to the conventional method of storing the outer cylinder 1 in a hermetically sealed manner.

Note that it is also possible to separate only the injection electrodes 118, 11b, . . . from the sputter electrodes 12a, 12b, . . . and store them in the container 23, and in this case, the storage volume can be further reduced.

[Effects of the Invention] As described above, according to the radioactive gas immobilization device of the present invention, it is possible to efficiently immobilize radioactive gas without increasing the size of the 11i radioactive gas immobilization device, Furthermore, the storage volume of radioactive gas can be significantly reduced compared to the conventional method.

In the embodiments described above, krypton was used as the radioactive gas, but the present invention is not limited to such embodiments. Of course, it can also be applied to J sparrow 4 sex swords.

[Brief explanation of drawings]

Figure 1 shows a conventional radioactive gas fixation device;
FIG. 2 is a longitudinal cross-sectional view showing a radioactive gas fixing device according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram illustrating a method for storing the injection electrode and sputtering electrode shown in FIG. 2. １・・・・・・・・・・・・・・・・・・Outer tube 2・・・・
・・・・・・・・・・・・・・・Inner tube 6・・・・・・
・・・・・・・・・・・・Power supply 11a, 111)・
... Injection electrodes 12a, 12b ... Sputter electrode 13 ... ...... Container 23
・・・・・・・・・・・・・・・・Storage Container Representative Patent Attorney Sa Suyama - 1st Bo. 3rd Sergeant 2nd

Claims (2)

[Claims] (1) A plurality of flat electrodes arranged at regular intervals in a sealed container, and an application device that applies opposite voltages to adjacent electrodes among these electrodes. A radioactive gas immobilization device comprising: a radioactive gas supply device that supplies a release gas into the sealed container; and a pressure reduction device that reduces the pressure inside the sealed container. (2) The radioactive gas immobilization device according to claim 1, wherein the radioactive gas is l(r -85).