JP2001091695A - Radioactive waste storage facilities provided with detoxification device for harmful chlorine-based organic matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide low-cost and practical waste storage facilities capable of executing detoxification processing by decomposing harmful chlorine-based organic matter contained in waste by use of γ-rays emitted from the waste in the high-dose waste storage facilities. SOLUTION: In the case of use of high-level radioactive waste liquid stored in a tank as a radiation source of γ-rays, residence means such as a jacket, a coil and a conveyer are provided around the high-level waste storage tank together with a supply means and a taking-out means of processed matter such that the processed matter is irradiated with γ-rays emitted from a surface of the storage tank over a prescribed time. In the case of use of one of a spent control rod, a channel box and a glass solidified body of the high-level radioactive waste liquid as a solid radiation source, plural tube-like radiation source storage vessels are linearly, nearly vertically aligned and are respectively filled with the radiation sources, and the residence means of the processed matter are provided near the line of the radiation source storage vessels to irradiate the processed matter with γ-rays over a prescribed time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for decomposing harmful chlorine-based organic substances by using gamma rays emitted from stored radioactive substances in a radioactive waste storage facility with a high dose. Concerning facilities with an attached.

[0002]

2. Description of the Related Art Hazardous chlorine contained in various wastes, such as changing dioxins in incineration ash containing dioxins into harmless ones and disposing of PCBs recovered from waste transformers. Attempts have been made to decompose organic substances to make them harmless. As this measure, many methods such as a pyrolysis method, a high-temperature incineration method, a chemical dechlorination method, an ultraviolet irradiation method, and an electron beam irradiation method have been developed and put into practical use. For example, Japanese Patent No. 2549755
As a method of removing dioxin generated in incineration ash generated by incineration of garbage, it discloses that water is added to the incineration ash and irradiated with ionizing radiation such as an electron beam.

[0003] However, the progress of such processing methods has not been successful. The reasons are that the configuration of the processing equipment is complicated, that advanced operation technology is required, and that equipment and operation costs are high.

As another means for decomposing harmful chlorine-based organic substances, a radiation (β-ray or γ-ray) irradiation method has been proposed. The above-mentioned Patent No. 2549755 also mentions β rays and γ rays as one of the ionizing radiations. Although irradiation with these radiations has been confirmed to be effective, there are the following obstacles before practical use. The β-ray irradiation method has a problem in that the generator is expensive and the range of β-rays is short, so that a large irradiation area must be taken to treat a large amount of waste. γ
X-ray irradiation is suitable as a radiation source acting on chlorinated organic substances mixed in a large amount of waste, because the range of γ-rays is longer than that of β-rays. In order to obtain from an artificial source such as cobalt 60, the cost of obtaining and maintaining the source becomes enormous,
It will not be economically viable as a waste treatment business.

On the other hand, used control rods, channel boxes, or vitrified high-level radioactive liquid waste produced in nuclear fuel reprocessing plants, which are generated during the operation of nuclear power plants, are constantly exposed to high doses of γ-rays. It is emitting radiation mainly composed of, but it is not available for use, but is simply stored as high-dose waste in a treatment facility in order to wait for natural attenuation. The high-level radioactive waste liquid before the vitrification is stored in a storage tank called “HAW tank”, which is a controlled area with a high dose level. The controlled area has been hitherto the only downside, and no attempt has been made to actively utilize the radiation that is flying there.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the harmful chlorine-based organic matter contained in waste by utilizing the radiation emitted from the high-dose waste storage facility, in particular, by using gamma rays. It is an object of the present invention to provide a storage facility capable of carrying out low-cost and practical detoxification processing by performing decomposition.

[0007]

The high-dose radioactive waste storage facility according to the present invention irradiates an object to be treated with radiation to decompose and detoxify harmful chlorine-based organic substances contained therein. For storing high-dose radioactive waste, and there are two modes depending on whether a liquid or a solid is used as a radiation source.

The former uses a high-level radioactive waste liquid stored in a tank as a radiation source, and at least a part of the periphery of the high-level waste storage tank receives an object to be treated from one side and exits from the other side. During, a stagnation means configured to receive irradiation of γ-rays emitted from the storage tank surface for a certain time is provided in proximity to the storage tank,
It is characterized in that means for supplying and taking out the object to be treated are provided.

In the latter case, a plurality of cylindrical source storage containers are arranged in a substantially vertical direction along two parallel straight lines.
Between the two rows, there is provided retention means configured to receive irradiation of γ-rays emitted from the surface of the source container for a predetermined time while the object to be processed enters from one side and exits from the other side. It is characterized in that means for supplying and taking out the object are provided.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a liquid is used as a radiation source includes an apparatus used when an object to be processed is also a liquid, for example, a PCB. The first means for retaining the object to be treated in such an apparatus is a jacket provided in contact with the outside of the side wall of the storage tank. When installed alongside an existing storage facility, this jacket does not need to be in contact with the storage tank, and is provided close to the outside of the side wall (1A) of the storage tank (1) as shown in FIGS. It may be a hollow plate-shaped container (2A). The container has a liquid injection line (3A) and a discharge line (3B).

FIGS. 3 and 4 show a modification in which the hollow plate-shaped container (2A) in the apparatus of FIGS. 1 and 2 is replaced with a coil (2B).

An apparatus used when the object to be treated is an individual, for example, soil contaminated with a chlorinated hydrocarbon solvent includes:
Those having a structure as shown in FIGS. 5 and 6 are suitable. In this embodiment, the means for retaining the object to be processed are two spring conveyors (4) provided to be inclined near the outside of the side wall of the storage tank. At both ends of the spring conveyor, a hopper (5A) for supplying an object to be processed and a belt conveyor (5B) for collecting processed solids are provided. Of course, in this embodiment, two or more spring conveyors may be arranged on one side, if desired.

When a solid is used as the radiation source, a plurality of cylindrical radiation source containers are arranged in a substantially vertical direction in a straight line, and the used control rod of the nuclear reactor is placed inside the radiation source container. ,
Filling the source selected from the channel box and the high-level radioactive waste vitrified material for one or both sides of the row of the source storage container for a period of time while the workpiece enters from one side and exits from the other side A facility provided with a staying means configured to receive irradiation of γ-rays emitted from the surface of the radiation source container and provided with means for supplying and taking out the object to be treated is appropriate.

Also in this embodiment, when the object to be processed is in a liquid state, a hollow plate or a coil as shown in FIGS. 1 to 4 may be used as a means for retaining the object to be processed. it can.

On the other hand, when the object to be processed is a solid object, a belt conveyor may be used as a means for retaining the object to be processed, similar to the examples shown in FIGS. FIG. 7 shows an example of such an embodiment, in which the radiation source containers (6) are arranged in two rows, and the belt conveyor (7) moves between them to carry the object to be processed. .

As described above, a source selected from a used control rod, a channel box, and a vitrified high-level radioactive liquid waste is used. The vitrified material usually has a predetermined size (430 mm in diameter, 1370 in height).
mm), it can be filled in the source container as it is. Conversely, the inner diameter of the source storage device should be of a size that is convenient for access to the canister. When a used control rod or channel box is used, an appropriately sized canister (for example, the same diameter and
It is preferable to prepare a double source and handle it with the radiation source inserted therein.

Typical values of the amount of γ-rays emitted by the γ-ray source used in the apparatus of the present invention are as follows, and the high-level radioactive liquid waste tank 10 ⁴ Gy / hr used control rod 32 Gy / hr Channel box 910 Gy / hr vitrified body 2030 Gy / hr About the PCB-containing transformer, the contaminated PCB (50 pp
m) to be below the treatment reference value (0.5 ppm)
1,000 kGy irradiation was required. Based on these values, the scale of the radiation source required for the processing, the speed at which the object to be processed is sent to and removed from the apparatus, and the like may be determined. When using gamma rays from the existing high-level radioactive waste liquid tank,
Since the dose that can be used for decomposing harmful chlorine-based organic substances is a given condition, the supply rate of the object to be treated is determined based on the given condition.

As is well known, a source emitting strong gamma rays, such as a vitrified body, generates heat from itself. When a vitrified body is used as the radiation source in the present invention, it is expected that the temperature inside the facility will increase.
From the viewpoint of promoting the decomposition reaction, it is rather preferable to raise the temperature to some extent, but it is still a matter of degree, and it is still necessary to avoid an excessively high temperature inside the container. In the facility shown in FIG. 7, air for cooling is taken in from the introduction shaft (8A), and is cooled by the outlet shaft (8A).
Cooling is performed by discharging from B).

[0019]

The facility of the present invention utilizes a high-level radioactive liquid waste, which is a waste of nuclear power generation, as a source of energy for decomposing organic substances, or a used control rod,
By utilizing the gamma rays emitted by the channel box or vitrified material, the cost of the source was kept at a low value close to zero and a high radiation dose could be secured.
Practical detoxification treatment by decomposing harmful chlorine-based organic substances by γ-ray irradiation, which was not practically used in the past in terms of cost, succeeded in detoxifying harmful substances at the same time as storing radioactive waste. .

Specific objects that can be detoxified by the equipment provided in the facility of the present invention include transformer insulating oil containing PCB,
It covers a wide range such as soil contaminated with PCBs and chlorinated hydrocarbon solvents, various wastes, incineration ash containing dioxins, and soil contaminated with dioxins.

The detoxifying device is manufactured and operated,
No advanced technology is required, considering the gamma-ray dose emitted by the source used, the amount of the object to be treated and the dose required to decompose the chlorine-based organic substances contained in it, The operating conditions such as the speed at which the object is supplied may be determined. In particular, the mode using gamma rays emitted from the storage tank for high-level radioactive liquid waste can be implemented by adding a few facilities to existing facilities, and is highly practical.

[Brief description of the drawings]

FIG. 1 Among radioactive waste storage facilities equipped with a device for detoxifying harmful chlorine-based organic substances according to the present invention, a device in which a radiation source is a high-level radioactive liquid waste and which handles a liquid to be treated. The side view which shows the example of the facility which has.

FIG. 2 is a plan view of the facility shown in FIG. 1;

FIG. 3 is a side view showing a modification of the facility shown in FIG. 1;

FIG. 4 is a plan view of the facility shown in FIG. 3;

FIG. 5 is a radioactive waste storage facility equipped with a device for detoxifying harmful chlorine-based organic substances according to the present invention, in which the source is a high-level radioactive waste liquid and the device handles solid-state objects to be treated. The side view which shows the example of the facility which has.

FIG. 6 is a cross-sectional view of the facility in FIG. 5 in the II direction.

FIG. 7 shows a radioactive waste storage facility equipped with a device for detoxifying harmful chlorine-based organic substances according to the present invention, in which the radiation source is a vitrified high-level radioactive waste liquid, and the solid-state material is to be treated. The side view which shows the example of the facility which has the apparatus which handles a thing.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Storage tank 1A Side wall 2A Hollow plate-shaped container (retention means) 2B Coil (retention means) 3A Injection line 3B Take-out line 4 Spring conveyor (retention means) 5A Hopper 5B Belt conveyor 6 Source container 7 Belt conveyor 8A Air introduction Shaft 8B outlet shaft

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B09B 5/00 ZAB B09B 3/00 304G G21F 9/36 541 5/00 ZABT G21H 5/00 (72) Invention Person Katsuhiko Adachi 2205 Narita-cho, Oarai-machi, Higashi-Ibaraki-gun, Ibaraki Pref. Inside the Technical Research Institute of JGC Corporation (72) Inventor Manjuo 2-3-1 Minato Mirai, Nishi-ku, Yokohama-shi, Kanagawa Prefecture F-term (reference) 2E191 BA12 BA13 BA15 BB01 BD11 4D004 AA22 AA36 AA41 AB06 AB07 CA32 CA43 CB42 CB46

Claims (7)

[Claims] 1. A facility for storing high-dose radioactive waste, which is equipped with an apparatus for irradiating the object to be treated with radiation to decompose and detoxify harmful chlorine-based organic substances contained therein. Wherein at least a part of the periphery of the high-level radioactive liquid waste storage tank is configured to be irradiated with γ-rays emitted from the surface of the storage tank for a certain period of time while the object to be treated enters from one side and exits from the other side. A facility characterized in that the storage means is provided in proximity to the storage tank, and means for supplying and removing the object to be processed are provided. 2. A facility for storing a high dose of radioactive waste, which is provided with an apparatus for detoxifying a liquid object to be treated, wherein a means for retaining the object to be treated is provided outside a side wall of a storage tank. The facility according to claim 1, wherein the facility is a jacket provided in contact with the container or a hollow plate-shaped container provided close to the jacket. 3. A facility for storing a high dose of radioactive waste, which is provided with a device for detoxifying a solid object to be treated, wherein a means for retaining the object to be treated is provided outside a side wall of a storage tank. The facility according to claim 1, wherein the facility is a spring conveyor that is provided at an angle near to the spring conveyor. 4. A facility for storing high-dose radioactive waste provided with an apparatus for irradiating a treatment object with radiation and decomposing and detoxifying harmful chlorine-based organic substances contained therein. A plurality of cylindrical source storage containers are arranged in a straight line in a substantially vertical direction. Inside the source storage container, used control rods of a reactor, a channel box, and high-level radioactive waste glass. Fill the source selected from the solidified body,
One or both sides of the row of the source container are configured to be irradiated with γ-rays emitted from the surface of the source container for a certain period of time while the object to be processed enters from one side and exits the other. A facility provided with a staying means, and a means for supplying and taking out the object to be treated. 5. A facility for storing high-dose radioactive waste provided with a device for detoxifying a liquid object to be treated, wherein a hollow plate or a coil is used as a means for retaining the object to be treated. 5. The facility of claim 4, wherein 6. A facility for storing high-dose radioactive waste provided with a device for detoxifying a solid object to be treated, wherein a belt conveyor is used as a means for retaining the object to be treated. Facilities. 7. The apparatus according to claim 5, wherein a vitrified body is used as a radiation source, and cooling means is provided for preventing the inside of the facility from being heated by heat generated from the radiation source.