JP2019082343A - Radioactive waste disposal system and disposal method - Google Patents

Abstract

To provide a radioactive waste disposal system and disposal method that are high in safety, and high in disposal efficiency.SOLUTION: A system, which disposes contaminated water including a radioactive substance, comprises: a radioactive substance absorption filter that is made of a radioactive substance absorption filament base material carrying a heat-proof and proof pressure sealed container equipment; a heat-proof and proof pressure sealed container that accommodates a used filter having a radioactive substance absorbed, and can be heated at more than 100°C; discharge means that discharges gas and a solution left over in the container after hydrothermal decomposition, respectively; and solid reaction product solidification means that solidifies a solid reaction product left over in the container after the hydrothermal decomposition, using a coagulation reaction of a low melting point metal or a low melting point alloy. The heat-proof and proof pressure sealed container, which is one part of a flow channel of the contaminated water, can be preferably a sealed container by closing an inflow port and outflow port.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radioactive waste treatment technology generated by adsorbing and removing radioactive substances in contaminated water containing radioactive substances using a radioactive substance adsorbent.

  When piping or pressure vessels are damaged, as in the case of a nuclear power plant accident, there is a possibility that a large amount of reactor coolant water containing radioactive materials such as iodine 131, cesium 134, cesium 137, and strontium 98 may be leaked. is there. Among these radioactive materials, cesium-137 has a long half-life of 30 years, and if it leaks out of a nuclear power plant, it will adversely affect the environment for a long time.

A radioactive substance recovery sheet supporting zeolite is known as a radioactive substance adsorbent for adsorbing and removing the cesium 137 leaked from waste water (see, for example, Patent Document 1).
In addition, as a radioactive substance adsorbent, a cesium adsorbent comprising a hydrophilic fiber base material carrying a Prussian blue analog is known (see, for example, Patent Document 2). This is one obtained by immobilizing Prussian blue analogue inside the fiber. Since Prussian blue is generally a powder material insoluble in water, it is possible to adsorb cesium from polluted water and purify it according to such cesium adsorbent.
However, although zeolites and Prussian blue analogues have high adsorptive performance for radioactive substances, there is a problem that disposal is not easy because workers can not easily approach to highly contaminated adsorbents. The

JP, 2015-99140, A Revised 2013/27652 gazette

  In view of such a situation, an object of the present invention is to provide a radioactive waste processing system and method with high safety and high processing efficiency.

In order to solve the above problems, the radioactive waste treatment system of the present invention is a system for treating polluted water containing radioactive substances, comprising a radioactive substance-adsorbing fiber base material carrying a heat-resistant pressure-resistant closed container material, A radioactive substance adsorption filter for adsorbing radioactive substances and a used filter for absorbing radioactive substances, which can be heated at 100 ° C. or higher, and a gas and a solution remaining in the vessel after hydrothermal decomposition The solid reaction product is solidified by solidifying the solid reaction product remaining in the vessel after hydrothermal decomposition and discharging means for respectively discharging the low melting point metal (LMP) or the low melting point alloy. Means are provided.
With the above configuration, the radioactive substance can be disposed of safely and efficiently. In addition, in this specification, although radioactive substance mainly refers to cesium, it is not restricted to this. The term "contaminated water" is used to mean not only purified water that has been purified by a radioactive substance adsorption filter, but also purified water in which radioactive substances after purification treatment have been reduced. The low melting point metal or low melting point alloy is a metal or alloy characterized by a low melting point, and is an alloy mainly composed of zinc, indium, gallium, tin, bismuth, lead or the like.
Here, hydrothermal decomposition is water whose temperature and pressure have been adjusted to enhance reactivity, and is high reactivity possessed by supercritical water which is neither liquid nor gas nor subcritical water close to supercritical state. Is a process to disassemble.

Hydrothermal decomposition of the used filter in the heat and pressure resistant sealed container is controlled by adjusting the temperature and pressure in the state where the used filter is impregnated with the contaminated water, or in the state where the used filter is contained in the contaminated water It is carried out with water in the supercritical state which has enhanced the properties. Hydrothermal decomposition of the used filter makes it possible to reduce the volume of radioactive waste.
The heat- and pressure-resistant hermetic container is heated to 100 ° C or higher to thermally decompose the used filter. For example, the temperature and pressure may be controlled to heat to a high temperature such as 400 ° C or 700 ° C. From the above viewpoint, the used filter is hydrothermally decomposed by heating to 150 to 350 ° C. and using high reactivity of supercritical water and subcritical water. When the temperature at the time of heating is less than 150 ° C., the decomposition speed becomes slow. In addition, when the temperature exceeds 350 ° C., the radioactive substance moves into the solution and becomes easy to concentrate. Also, from the viewpoint of saving energy consumption, the temperature is preferably 350 ° C. or less. Originally, hydrothermal decomposition with a heat-resistant pressure-resistant closed container can be decomposed at lower temperatures and has better thermal efficiency than incineration treatment, but thermal efficiency can be further improved by performing hydrothermal decomposition in the above temperature range it can. In addition, it is significant from the viewpoint of confinement of radioactive substances.
In the solid reaction product solidification means, after the measurement of the solid reaction product by, for example, X-ray diffraction or Raman spectroscopy, the inside of the metal is made of a low melting point alloy. Contained in the solidifying process. The metal lump subjected to the solidification treatment can be a radioactive waste with a reduced radiation dose because the surface activity is reduced by the shielding effect of the low melting point alloy. The solid reaction product solidification means may be provided with means for discharging the solid reaction product.

In the radioactive waste treatment system of the present invention, it is preferable that the heat and pressure resistant sealed container is a part of the flow path of the contaminated water, and can be a sealed container by closing the inlet and the outlet.
The heat-resistant pressure-resistant sealed container is a part of the flow path of the contaminated water, so that the radioactive substance adsorption filter can adsorb the radioactive substance in a state of being installed in the heat-resistant pressure-resistant sealed container. As a result, after adsorption of the radioactive substance, it is possible to carry out the hydrothermal decomposition in the heat-resistant pressure-resistant closed container without moving the used filter separately, thereby enabling safe and efficient disposal.
The heat and pressure resistant sealed container is preferably an autoclave. Here, an autoclave is a container which can make an inside into high temperature high pressure.

In the radioactive waste treatment system of the present invention, the discharge means measures the radiation dose of the gas and the solution, and discharges it to the outside if the radiation dose is below a predetermined threshold, and if the radiation dose exceeds the predetermined threshold, It is preferable to pass through another adsorption filter different from the radioactive substance adsorption filter and discharge it to the outside.
Specifically, as for the gas generated by hydrothermal decomposition, as a result of analyzing the components and radiation dose by gas chromatography (Gas chromatography), it was determined that the radiation dose was less than or equal to a predetermined threshold and that no further treatment was necessary. In the case, it is discharged outside as it is. On the other hand, if the radiation dose exceeds the predetermined threshold value and it is determined that further processing is necessary, adsorption processing is performed using another adsorption filter different from the radioactive substance adsorption filter, and then outside Exhausted.

  In addition, for the solution generated by hydrothermal decomposition, as a result of analyzing the component and radiation dose by inductively coupled plasma mass spectrometry (ICP-Mass Spectrometry), it is determined that the radiation dose is below the predetermined threshold and that no further treatment is necessary. If it is, it is discharged to the outside as it is. On the other hand, if the radiation dose exceeds the predetermined threshold value and it is determined that further processing is necessary, adsorption processing is performed using another adsorption filter different from the radioactive substance adsorption filter, and then outside Exhausted. In addition, it is necessary to store as radioactive waste in order to attenuate a radiation dose about what was judged as impossible to discharge outside as a result of performing further processing.

  In the radioactive waste treatment system of the present invention, the low melting point alloy in the solid reaction product solidification means is preferably an alloy of indium and bismuth or an alloy of indium and tin. The low melting point alloy does not contain lead, so it can be a more environmentally friendly radioactive waste.

  The radioactive material adsorbent used in the radioactive waste treatment system of the present invention is preferably any one of Prussian blue analogues, zeolites, and silicitanates that mainly adsorb and remove cesium. The use of a radioactive substance adsorbent having high radioactive substance adsorption performance as described above enables efficient adsorption of radioactive substances.

  The radioactive substance-adsorbing fiber substrate used in the radioactive waste treatment system of the present invention is preferably a non-woven fabric, a woven fabric or a yarn. By making the radioactive substance-adsorbing fiber base material into a non-woven fabric, a woven fabric or a yarn, the radioactive substance in the contaminated water can be easily brought into contact with the radioactive substance adsorbent, and efficient adsorption of the radioactive substance is possible.

  The radioactive substance adsorption filter used in the radioactive waste treatment system of the present invention may be a filter formed in a mesh shape using a band-like radioactive substance adsorption fiber substrate carrying a radioactive substance adsorption material.

  The radioactive substance adsorption filter used in the radioactive waste treatment system according to the present invention has a corrugated core member in which a band-like radioactive substance adsorption fiber substrate carrying a radioactive substance adsorption material has a waveform of substantially the same shape on one side thereof. A filter which is adhered and wound in a roll shape, wherein contaminated water containing radioactive material is caused to flow with the gap of the corrugated core member as a flow path to adsorb the radioactive material onto the radioactive substance-adsorbing fiber substrate. It may be possible to purify contaminated water by

The radioactive substance adsorption filter used in the radioactive waste treatment system according to the present invention has a corrugated core member in which a band-like radioactive substance adsorption fiber substrate carrying a radioactive substance adsorption material has a waveform of substantially the same shape on one side thereof. A filter which is adhered and laminated so that corrugations alternate at right angles, and the contaminated water containing radioactive substance is made to flow by using the gap of the corrugated core member as a flow path, and radioactive substance is absorbed to the radioactive substance adsorption fiber substrate It may be possible to purify polluted water by adsorbing
Thus, the radioactive waste treatment system of the present invention can use various radioactive substance adsorption filters, and can be said to be a highly versatile system.

  The corrugated core member is preferably made of a band-like radioactive substance-adsorbing fiber substrate carrying a radioactive substance-adsorbing material. When the corrugated core member is made of the same material as the radioactive substance-adsorbing fiber substrate, the radioactive substance can be efficiently adsorbed. In addition, temperature control in hydrothermal decomposition is facilitated.

The radioactive waste disposal method of the present invention is a method for treating contaminated water containing radioactive material, and comprises the following steps 1) to 4).
1) Adsorption step for adsorbing radioactive substance in contaminated water by radioactive substance adsorption filter consisting of radioactive substance adsorption fiber base material supporting radioactive substance adsorption material 2) Used filter on which radioactive substance is adsorbed to heat-resistant pressure-resistant sealed container Heating step 3 for storing and heating at 100 ° C. or higher 3) Exhausting step 4 for discharging the gas and solution remaining in the vessel after hydrothermal decomposition 4) Solid reaction product remaining in the vessel after hydrothermal decomposition, having a low melting point Solid reaction product solidification step solidified using solidification reaction of metal or low melting point alloy

It is preferable that the heating step in the radioactive waste treatment method of the present invention be thermally decomposed at 150 to 350 ° C.
The heat and pressure resistant hermetic container is preferably heated to 150 to 350 ° C. to thermally decompose the used filter. Hydrothermal decomposition is carried out in the above temperature range because of decomposition speed, thermal efficiency, and confinement of radioactive substances in solid reaction products. However, it is also possible to carry out hydrothermal decomposition under conditions exceeding 350 ° C., and may be carried out under supercritical conditions exceeding 700 ° C.

  According to the radioactive waste treatment system and treatment method of the present invention, there is an effect that the radioactive substance adsorption filter can be disposed of safely and efficiently.

Schematic structure of the radioactive waste treatment system of Example 1 Flow chart of the radioactive waste treatment method of Example 1 Image of contaminated water Radioactive substance adsorption image of Example 1 Hydrothermal decomposition image of the used filter of Example 1 Image figure after hydrothermal decomposition The radioactive substance-adsorbing filter of Example 2 is as follows: (1) that the radioactive substance-adsorbing fiber base is in the form of a mesh, (2) that the radioactive substance-adsorbing fiber base is wound in the form of a roll, (3) These show what the radioactive material adsorption | suction fiber base material was laminated | stacked. Installation image of radioactive substance adsorption filter of Example 2

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings. In addition, the scope of the present invention is not limited to the following examples and illustrated examples, and many modifications and variations are possible.

FIG. 1 shows a schematic configuration diagram of the radioactive waste treatment system of the first embodiment. As shown in FIG. 1, the radioactive waste disposal system 1 comprises a radioactive substance adsorption filter 2, a heat and pressure resistant sealed container 3, a solid reaction product solidifying means 4, a gas discharging means 5, a solution discharging means 6 and a solid reaction product discharging. It consists of means 7. The radioactive substance adsorption filter 2 is installed and used in the heat and pressure resistant airtight container 3. The heat and pressure resistant sealed container 3 is provided with a gas discharge means 5 and a solution discharge means 6 so that the gas and solution generated when the used filter is subjected to the hydrothermal decomposition can be discharged. The heat-resistant pressure-resistant closed container 3 is provided with solid reaction product solidification means 4 and solid reaction product discharge means 7, and the solid reaction product discharged from the solid reaction product discharge means 7 solidifies the solid reaction product. The structure is solidified by means 4.
Note that, unlike the above-described configuration, after the solidifying process is performed by the solid reaction product solidifying means 4, the solidified material may be discharged.

  FIG. 2 shows a flow diagram of the radioactive waste disposal method of the first embodiment. As shown in FIG. 2, first, a radioactive substance adsorption filter is attached to the purification tank (S01). The radioactive substance in the contaminated water is adsorbed by the radioactive substance adsorption filter (S02). When the radioactive substance adsorption filter adsorbs sufficient radioactive substance and needs replacement, the autoclave performs hydrothermal decomposition of the used adsorption filter (S03). The solid reaction product is removed from the autoclave (S04), and solidified with a low melting point alloy (S05). For gases and liquids generated during hydrothermal decomposition with an autoclave, it is determined by measurement of components and radiation dose whether treatment is necessary (S06), and if treatment is not necessary, discharged to the outside ( S07). If the process is necessary, the necessary process is performed (S08), and the process is performed and discharged to the outside (S09).

  FIG. 3 shows an image of contaminated water. As shown in FIG. 3, the contaminated water 10 is contained in the container 12, and the contaminated water 10 contains the radioactive substance 11. Thus, the contaminated water 10 contaminated with the radioactive substance 11 is purified by the following system.

  FIG. 4 shows a radioactive substance adsorption image of Example 1. As shown in FIG. 4, a radioactive substance adsorption filter 20 is installed in the purification tank 8. The contaminated water 10 flows from the water intake 13 into the purification tank 8, is purified by the radioactive substance adsorption filter 20 installed in advance, and flows out to the drainage port 14. The radioactive substance-adsorbing filter 20 has a shape in which Prussian blue is used as a radioactive substance-adsorbing material, and a radioactive substance-adsorbing base material which is a non-woven fabric is woven. As shown in FIG. 4, the radioactive substance 11 in the contaminated water 10 is adsorbed by the radioactive substance adsorption filter 70.

FIG. 5 shows a hydrothermal decomposition image of the used filter of Example 1. As shown in FIG. 5, an autoclave 30 is used as the heat- and pressure-resistant closed container 3. The autoclave 30 is provided with valves (15a, 15b). The autoclave 30 is a container which can make the inside high temperature and pressure.
The radioactive substance adsorption filter 20 is installed in the autoclave 30. Since the radioactive substance adsorption filter 20 gradually loses its adsorption performance as it is used, it is necessary to replace the radioactive substance adsorption filter 20 as appropriate. However, if the radioactive substance adsorption filter 20 is taken out and discarded as it is, a large amount of waste is generated, which makes subsequent processing difficult. Therefore, by using the autoclave 30 to hydrothermally decompose the used radioactive material adsorption filter 20, it is possible to reduce the volume of the used radioactive material adsorption filter 20.

When the hydrothermal decomposition is performed by the autoclave 30, the valve 15a provided at the water intake 13 and the valve 15b provided at the drainage opening 14 are closed, and the inside of the autoclave 30 is sealed. The temperature for hydrothermal decomposition is 150 to 350 ° C. In the inside of the autoclave 30, not only the used radioactive substance adsorption filter 20 which adsorbed the radioactive substance 11 but also the polluted water 10 remains, and the hydrothermal decomposition is performed by the autoclave 30 in such a state Although possible, hydrothermal decomposition may be performed after discharging a certain amount of the contaminated water 10 as necessary.
For convenience of explanation, FIG. 4 shows a radioactive substance adsorption image by the radioactive substance adsorption filter 20 installed in the purification tank 8, and FIG. 5 shows a hydrothermal decomposition image of the used filter by the autoclave 30. Although shown, in fact, the autoclave 30 is integrally installed in the purification tank 8, and after purification of the polluted water 10 by the radioactive material adsorption filter 20, the used radioactive material adsorption filter 20 is cleaned. The structure is such that hydrothermal decomposition can be performed by the autoclave 30 without taking it out of the unit 8.

FIG. 6 shows an image after hydrothermal decomposition. As shown in FIG. 6, the spent radioactive material adsorption filter 20 shown in FIG. 5 becomes a solid reaction product 16 by the hydrothermal decomposition by the autoclave 30. A gas (not shown) generated in the hydrothermal decomposition is discharged by the gas discharging means 5. The liquid 17 generated in the hydrothermal decomposition is discharged by the solution discharging means 6.
The solid reaction product 16 is removed from the autoclave 30 by the solid reaction product discharge means 7 and solidified by the solid reaction product solidifying means 4 shown in FIG. In the solid reaction product solidifying means 4, although not shown, the solid reaction product 16 is a low melting point alloy consisting of indium and bismuth or indium and tin after being measured by X-ray diffraction or Raman spectroscopy. Is poured and solidified. As a result, a metal mass in which the solid reaction product 16 is confined is formed inside the low melting point alloy, and it can be managed as radioactive waste with a reduced radiation dose.

The gas generated in the hydrothermal decomposition is not shown, but the component and radiation dose are measured by gas chromatography, and if there is no problem even if the gas is discharged to the outside, the gas discharge means 5 directly discharges it to the outside Be done. If it is determined that the process is necessary as a result of the measurement, the necessary process is performed.
Although the liquid substance 17 generated in the hydrothermal decomposition is not illustrated, the component and radiation dose are measured by the inductively coupled plasma mass spectrometer, and if there is no problem even if it is discharged to the outside, the solution discharging means 6 , Will be discharged to the outside as it is. As a result of the measurement, if it is determined that the treatment is necessary, the necessary treatment is carried out and then it is discharged to the outside.

  FIG. 7 shows the radioactive substance-adsorbing filter of Example 2, wherein (1) is a network of radioactive substance-adsorbing fiber base and (2) is a roll of radioactive substance-adsorbing fiber base. And (3) show that the radioactive substance-adsorbing fiber base material is laminated.

As shown in FIG. 7A, the radioactive substance adsorption filter 21 is composed of an adsorption cloth net 21a, a float member 21b and a weight member 21c. A plurality of ring-shaped connecting members 21d are provided at upper, lower, left, and right ends of the suction cloth net 21a, respectively, and the suction cloth net 21a and the float member 21b are connected via the connecting members 21d. Similarly, the suction cloth net 21a and the weight member 21c are also connected via the connection member 21d. Although the connecting members 21d provided at the left and right ends of the suction cloth net 21a are not connected to any members here, they can be connected to other nets and the like as needed. ing.
By providing the float member 21b and the weight member 21c, the radioactive substance adsorption filter 21 sinks and floats to a certain extent in a state where the adsorption cloth net 21a vertically spreads when it is submerged in the purification basin, so that radioactive substances in water are eliminated. Can be effectively adsorbed.
The suction cloth net 21a, the float member 21b, the weight member 21c, and the connection member 21d are all formed of a material that can be hydrothermally decomposed at a temperature of 150 to 350 ° C., as shown in FIG. Hydrothermal decomposition is possible by the autoclave 30.

As shown in FIG. 7 (2), the radioactive substance adsorption filter 22 comprises a radioactive substance adsorption cloth 22a and a corrugated center member 22b. Specifically, the corrugated core member 22b provided on one side of the radioactive substance-adsorbing cloth 22a is turned to the outside, and is rolled into a roll. As a method of making it roll-shaped, not only the external winding which the waveform as shown in FIG. 7 (2) points outside but also any method of the inner winding which makes the surface provided with the corrugated center member 22b inside It is possible.
The radioactive substance adsorption filter 22 is provided with a large number of gaps 22c, so that the contaminated water flowing in the gaps 22c can easily come into contact with the radioactive substance adsorption filter 22, thereby efficiently treating a large amount of contaminated water. be able to.
The radioactive substance-adsorbing cloth 22a and the corrugated center core member 22b are both made of a radioactive substance-adsorbing fiber substrate carrying a radioactive substance-adsorbing material, and can be hydrothermally decomposed at a temperature of 150 to 350.degree. It is possible to hydrolyze by the autoclave 30 shown in FIG. 5 or FIG.

As shown in FIG. 7 (3), the radioactive substance adsorption filter 23 is composed of a radioactive substance adsorption cloth 23a and a corrugated center member 23b. Specifically, although the corrugated material core member 23b is provided on one side of the radioactive substance-adsorbing cloth 23a, the layers are laminated such that the waveforms of the corrugated material core member 23b are alternately orthogonal.
Since the radioactive substance adsorption filter 23 is provided with a large number of gaps 23c, the contaminated water flowing through the gaps 23c is structured so that the radioactive substance adsorption filter 23 can easily come into contact, effectively treating a large amount of contaminated water. be able to.
Although the radioactive substance adsorption filter 23 has a substantially cubic shape, it may be shaped by changing the length and the width as needed. In addition, although the waveforms are stacked so that the waveforms are alternately orthogonal to each other, it is not necessary to change the stacking direction for each sheet. For example, the stacking direction may be changed for every two sheets.
The radioactive substance-adsorbing cloth 23a and the corrugated center core member 23b are both made of a radioactive substance-adsorbing fiber substrate carrying a radioactive substance-adsorbing material, and are formed of a material which can be hydrothermally decomposed at a temperature of 150 to 350 ° C Because of this, it is possible to hydrothermally decompose by the autoclave 30 shown in FIG. 5 or FIG.
As described above, in the radioactive waste treatment system of the present invention, it is possible to use various radioactive substance adsorption filters (21 to 23), and it can be said that the system is highly versatile.

  FIG. 8 shows an attachment image of the radioactive substance adsorption filter of the second embodiment. As shown in FIG. 8, in the radioactive waste treatment system 1, the radioactive substance adsorption filter 22 shown in FIG. 7 (2) is attached to the purification tank 8. Specifically, as shown in FIG. 8, a radioactive substance adsorption filter 22 is placed in a net-like container 19 and installed as a radioactive substance adsorption device 18 in the purification tank 8. The purification tank 8 has a structure in which the contaminated water 10 flows in from the water intake 13, is purified by the radioactive material adsorption device 18, and the contaminated water 10 after purification flows out to the outlet 14.

When the radioactive substance adsorption device 18 is installed in the purification tank 8, the lid 9 is removed, and the radioactive substance adsorption device 18 is sunk in the purification crucible 8. Since the net-like container 18 is formed of a soft material, it can be easily deformed and can be installed in accordance with the shape of the purification crucible 8. Moreover, as shown in FIG. 8, it is also possible to install two radioactive substance adsorption devices 18 in piles. In addition, it is also possible to install three or more according to the shape etc. of the purification cage 8.
In addition, since the net-like container 18 is formed of a material that can be hydrothermally decomposed at a temperature of 150 to 350 ° C., it can be hydrothermally decomposed by the autoclave 30 shown in FIG. 5 or FIG. .

  The present invention is useful as a system or method for treating radioactive waste.

DESCRIPTION OF SYMBOLS 1 radioactive waste disposal system 2, 20-23 radioactive substance adsorption filter 3 heat-resistant pressure-resistant closed container 4 solid reaction product solidification means 5 gas discharge means 6 solution discharge means 7 solid reaction product discharge means 8 purification tank 9 lid 10 contamination Water 11 radioactive substance 12 container 13 intake port 14 drain port 15a, 15b valve 16 solid reaction product 17 liquid substance 18 radioactive substance adsorption device 19 net-like container 21a adsorption cloth net 21b float member 21c weight member 21d connecting member 22a, 23a radioactive Material adsorption cloth 22b, 23b Corrugated core member 22c, 23c Gap 30 Autoclave

Claims (12)

A system for treating contaminated water containing radioactive material, comprising:
A radioactive substance adsorption filter comprising a radioactive substance-adsorbing fiber substrate carrying a radioactive substance-adsorbent and adsorbing the radioactive substance in the contaminated water;
A heat-resistant pressure-resistant hermetic container which accommodates the used filter having adsorbed a radioactive substance and which can be heated at 100 ° C. or higher;
An exhausting means for respectively discharging the gas and the solution remaining in the container after the hydrothermal decomposition;
Solid reaction product solidifying means for solidifying the solid reaction product remaining in the container after hydrothermal decomposition using solidification reaction of low melting point metal or low melting point alloy;
Radioactive waste treatment system equipped with   The radioactive waste treatment system according to claim 1, wherein the heat-resistant and pressure-resistant closed container is a part of a flow path of contaminated water and can be a closed container by closing an inlet and an outlet. The discharge means is
Measuring the radiation dose of the gas and the solution;
If the radiation dose is below the specified threshold, it is discharged to the outside,
When the radiation dose exceeds a predetermined threshold value, it passes through another adsorption filter different from the radioactive substance adsorption filter and is discharged to the outside.
The radioactive waste disposal system according to claim 1 or 2 characterized by things.   The radioactive waste treatment system according to any one of claims 1 to 3, wherein the low melting point alloy in the solid reaction product solidifying means is an alloy of indium and bismuth or an alloy of indium and tin.   The radioactive waste treatment according to any one of claims 1 to 4, wherein the radioactive material adsorbent is any one of Prussian blue analogue, zeolite, and silicitanate which mainly adsorbs and removes cesium. system.   The radioactive waste disposal system according to any one of claims 1 to 5, wherein the radioactive substance-adsorbing fiber substrate is a non-woven fabric, a woven fabric or a yarn.   7. The filter according to any one of claims 1 to 6, wherein the radioactive substance adsorption filter is a filter formed in a mesh shape using the band-like radioactive substance adsorption fiber base material carrying the radioactive substance adsorbent. Radioactive waste treatment system as described. In the radioactive substance-adsorbing filter, a band-like radioactive substance-adsorbing fiber substrate carrying the radioactive substance-adsorbing material is adhered to a wavelike core member having substantially the same waveform on one side surface, and wound in a roll Filter, and
Contaminated water containing radioactive material is flowed through the gap of the corrugated core member as a flow path, and the contaminated material can be purified by adsorbing the radioactive material to the radioactive substance-adsorbing fiber substrate. The radioactive waste treatment system according to any one of Items 1 to 6. In the radioactive substance-adsorbing filter, a band-like radioactive substance-adsorbing fiber substrate carrying the radioactive substance-adsorbing material is adhered to a waveform core member having substantially the same shape on one side surface, and the waveforms alternate alternately Filters stacked in order to
Contaminated water containing radioactive material is flowed through the gap of the corrugated core member as a flow path, and the contaminated material can be purified by adsorbing the radioactive material to the radioactive substance-adsorbing fiber substrate. The radioactive waste treatment system according to any one of Items 1 to 6.   The radioactive waste treatment system according to claim 8 or 9, wherein the corrugated core member comprises a band-like radioactive material-adsorbing fiber base material carrying a radioactive material-adsorbing material. A method of treating contaminated water containing radioactive material, comprising:
An adsorption step of adsorbing radioactive substances in contaminated water by a radioactive substance adsorption filter comprising a radioactive substance-adsorbing fiber substrate carrying a radioactive substance-adsorbing material;
A heating step of housing the used filter to which a radioactive substance has been adsorbed in a heat-resistant pressure-resistant closed container and heating at 100 ° C. or higher;
Discharging the gas and the solution remaining in the container after hydrothermal decomposition;
A solid reaction product solidifying step of solidifying the solid reaction product remaining in the vessel after hydrothermal decomposition using a solidification reaction of a low melting point metal or a low melting point alloy;
A radioactive waste disposal method characterized by comprising. The radioactive waste disposal method according to claim 11, wherein the heating step is hydrothermally decomposed at 150 to 350 ° C.