EP2352155A1

EP2352155A1 - Method and apparatus for vitrification of radioactive waste

Info

Publication number: EP2352155A1
Application number: EP09822143A
Authority: EP
Inventors: Sang Guk Lee; Sang Don Lee
Original assignee: So-Myoung Special Construction Co Ltd
Current assignee: So-Myoung Special Construction Co Ltd
Priority date: 2008-10-24
Filing date: 2009-08-20
Publication date: 2011-08-03
Also published as: JP2011530698A; WO2010047467A1; CN102105944B; JP5249417B2; CN102105944A; KR100880823B1; WO2010047467A9

Abstract

The present invention relates to an apparatus for solidification of radioactive waste comprising a solidification drum (120) capable of accommodating radioactive waste in powdered, granulated and various others forms; a polymer injection device (110) that injects polymers into said solidification drum and mixes said polymers with radioactive waste contained therein; a measuring device (111) that measures the amount of polymer injected into said solidification drum; an internal vacuum suction device (121) inserted into the bottom of said solidification drum; a vacuum pump (130) connected to said internal vacuum suction device; a controller (140) that controls said polymer injection device (110) and said vacuum pump (130) based on signals received from said measuring device (111); and a recovery container (150), connected to said internal vacuum suction device, that collects excess polymers flowing out of said solidification drum and enables verification of the polymer permeation status inside the same.

Description

[Technical Field]

The present invention relates to a method and apparatus for solidification of radioactive waste and, more particularly, to a method and apparatus for solidification of radioactive waste which facilitates hermetic infiltration of a solidification material into granulated, powdered and various other forms of radioactive waste through alternate control between polymer injection and vacuum suction, so that void generation inside a solidified waste can be minimized to enhance the strength of the solidified waste, unexpected effluent accidents during solidification can be prevented through multiple safeguards to enhance safety during operation, and radioactive waste can be more safely stored at lower cost by maximizing waste density.

[Background]

The operation of nuclear power plants inevitably generates large amounts of radioactive liquid waste which are generated in a radioactive management zone and are generally treated by evaporation in an evaporator. In this procedure, concentrated liquid waste remains at the bottom of the evaporator. Such liquid wastes, for example, low-level radioactive waste, are subjected to evaporation, enrichment, and confrication through a Concentrated Waste Drying System (CWDS) resulting in powdered waste. The powdered waste can be solidified using various methods.
Among various solidification methods, cement solidification is the oldest known method, exhibiting excellent compressive strength and durability, but suffers from low waste storage density. Furthermore this method presents several other disadvantages/flaws: a solidified waste exhibits decreased leach-resistance due to free water present in cement, the iron drum which stores the solid waste is prone to corrosion over length of time, a large amount of cement is consumed due to poor radioactive shielding capabilities of the cement, and due to the large volume of the solidified waste a larger storage pace is required for storage.
Asphalt solidification is excellent in terms of waste storage density and leach-resistance. However, this method suffers from low durability. For example, solidified solid wastes generated through this method exhibit poor shape stability and compressive strength, and the process runs a risk of fire during operations. In 1997, a fire broke out in the asphalt solidification facilities of Dokai's reprocessing facility in Japan.
Alternatively a paraffin solidification method is likely to cause non-uniform solidification due to layer separation during the manufacturing process.
After reviewing current liquid waste management methods, and in an attempt to reconcile the shortcomings of those methods, polymer solidification technology approved by the US Nuclear Regulatory Commission (NRC) has been adopted as the replacement for current concentrated waste liquid management methods (cement, asphalt, and paraffin solidifications).
When applying polymer solidification technology to radioactive waste, the solidification drum is capable of accommodating powdered wastes of various sizes and shapes including particles with a diameter of several micrometers. The majority of powdered wastes are elementary solid particle type wastes, which is difficult for a polymer used as the solidification material to infiltrate thereto that solidification based on mechanical mixing with the polymer is adopted. However, if the solidification material is mechanically mixed and solidified with the polymer, waste storage density is decreased, thus, increasing the amount of solidified waste generated when disposing of a fixed amount of radioactive waste. As a result, not only do disposal expenses become economically inefficient but the mixing process is disadvantageous in terms of safety.
Due to the hazardous nature of radioactive waste, the solidification management process of radioactive wastes must be performed in a remote area. However, the solidification process runs the risk of polymer leakage or overflow through unanticipated accidents. For example, even a simple power failure can result in the waste management apparatus to halt operations and can potentially result in the polymer being adhered to the apparatus. Even the slightest accident can result in massive environment damage and entail huge recovery efforts due to the nature of radioactive waste. Thus, a safety device for preventing such accidents during apparatus operations is required.
Korean Patent No. 0848507 discloses an apparatus and method for solidification of radioactive waste powder in which an adhesive is prepared by spraying both radioactive waste powder and a polymer, and is then heated for solidification, or the adhesive is molded into an annular body and solidified by injecting and heating the polymer into the annular body. This technique is a modified variation of mechanical mixing and is fundamentally different from the present invention wherein forcible infiltration into waste powders is performed through alternate control between polymer injection and vacuum suction as opposed to mechanical mixing. This technique unfortunately shares the shortcomings of the mechanical mixing which causes a reduction in waste storage density of the solidified solid, and is very disadvantageous in terms of radioactive safety as a result of spraying the radioactive waste powder. Moreover, since heating of the solidified solid for polymer curing in this technique does not match with technical requirements for reduced polymer heat shock, it is difficult to apply this technique on-site at nuclear power plants.
Korean Patent No. 0848505 discloses an apparatus which includes a solidification device for radioactive waste in a container to be loaded onto a vehicle, thereby collecting liquefied radioactive-waste, such as radioactive sludge, liquid waste, or the like to achieve direct solidification of the radioactive waste on-site during movement. However, this technology is unrelated to the present invention.
U.S. Patent 4,851,155 discloses an apparatus for solidification of radioactive waste. In this apparatus, a solidification material is mechanically mixed outside a drum and injection of the solidification material is promoted by negative pressure generated in the closed drum using a degassing means when the mixed solidification material is injected into the solidification drum closed off by a cap. When a filling sensor detects that the solidification material has reached a certain threshold, the injection of the solidification material is stopped and the solidification material in the drum is hardened with heat supplied by an indirect heater, thereby forming waste solids.
In this apparatus, however, the polymer having low viscosity is naturally infiltrated into the waste by the weight thereof, osmotic pressure, etc., and is then hardened by heat, which is applicable only when a specially designed and manufactured waste drum is closed - making it inapplicable to a high viscosity polymer. Thus, this technique is fundamentally different from the present invention, which allows the use of polymer with high viscous properties to infiltrate void inside wastes by alternate control between polymer injection and vacuum suction. Additionally the present invention accommodates various sizes of open drums and is equipped with multiple safety devices to anticipate unexpected errors or accidents during operation. Moreover, since this technique of hardening the solidification material inside the drum through an indirect heater during the solidifying stage conflicts with technical requirements for reduced polymer heat shock, it is difficult to apply this technique on-site at nuclear power plants.

[Disclosure]

[Technical Problem]

The present invention is conceived to rectify and solve the aforementioned procedures and its shortcomings of radioactive waste management, and other problems of the related field. An aspect of the present invention is to provide a method and apparatus for solidification of radioactive waste, in which a solidification material is easily and hermetically infiltrated into granulated, powdered and various other forms of radioactive waste through alternate control between polymer injection and vacuum suction, so that void generation inside a solidified solid of the waste can be minimized to enhance strength of the solidified solid, as well, unexpected effluent accidents during solidification can be prevented by multiple safeguards, and radioactive waste can be safely stored at lower cost in a disposal site by maximizing waste storage density.

[Technical Solution]

In accordance with one aspect of the present invention, a method for solidification of radioactive waste includes:

injecting a solidification polymer through a polymer injection device into a solidification drum filled with various forms of radioactive waste including powdered and granulated variations;
gradually infiltrating the polymer into voids sections of the radioactive waste by implementing alternate control between polymer injection and vacuum suction once or more through the polymer injection device and an internal vacuum suction device inserted into the bottom of a solidification drum;
ascertaining an infiltrated state of the polymer inside the solidification drum through a recovery container that is connected to the internal vacuum suction device for ascertaining an infiltrated state of the polymer inside the solidification drum; and
burying and solidifying the internal vacuum suction device inside the solidification drum together with the solidified solid.

The infiltrating of the polymer may include injecting the polymer through the polymer injection device and infiltrating the injected polymer into the void gaps in the radioactive waste by gravity if a measuring device, used for measuring a level of the polymer, detects that the level of the polymer is lower than the minimum threshold based on the thickness of the polymer laid on the radioactive waste inside the solidification drum; operating both the polymer injection device and a vacuum pump connected to the internal vacuum suction device and infiltrating the polymer into the solidification drum if the sensed level of the polymer is greater than or equal to the minimum threshold and lower than the maximum threshold; and stopping the polymer injection device, operating only the vacuum pump and infiltrating the polymer into the voids in the radioactive waste by the vacuum suction if the sensed level of the polymer is greater than or equal to the maximum threshold.
The mixing and injecting the polymer may include mixing and injecting the polymer while one or two or more polymer mixing static nozzles replaceable as consumables when the polymer is adhered due to interruption of electric power are fixed or rotated in the polymer injection device.
In accordance with another aspect of the present invention, an apparatus for solidification of radioactive waste includes: a solidification drum 120 that accommodates the radioactive waste; a polymer injection device 110 that mixes and injects a polymer into the radioactive waste; a measuring device 111 that senses the level of the polymer injected into the solidification drum; an internal vacuum suction device 121 that is inserted at the bottom of a solidification drum filled with the radioactive waste; a vacuum pump 140 that is connected to the internal vacuum suction device 121; a controller 150 that processes a sensed signal from the measuring device 111 and controls operation of the polymer injection device 110 and the vacuum pump 140; and a recovery container 130 connected to the internal vacuum suction device 121 which recovers the excess polymer flowing out from the solidification drum, and ascertains an infiltrated state of the polymer inside the solidification drum.
A minimum of two measuring devices 111 may be installed for sensing the level of the polymer injected into the solidification drum as a safeguard against abnormal operation, and the most conservative value between values measured by the installed measuring devices may be used as input for automatically controlling operation of the polymer injection device and the vacuum pump through the controller 150.
The recovery container 130 responsible for recovering the excess polymer flowing out from the solidification drum and enabling the infiltrated state of the polymer inside the solidification drum to be ascertained may be observed from the outside with the naked eye or through a Closed Circuit Television (CCTV). To prevent the overflow of the recovered polymer, a recovered polymer measuring device 131 may be attached to the recovery container, signaling a warning to automatically stop the operation of the vacuum pump and the polymer injection device should the amount of polymer recovered in the recovery container exceed a certain amount.
The internal vacuum suction device 121, inserted at the bottom of the solidification drum filled with the radioactive waste, may have a disc-shaped lower surface formed with multiple grooves or projections or provided with an air-permeable non-woven fabric to use as a gap between the lower surface of the internal vacuum suction device and the bottom of the solidification drum 120, thereby reducing the amount of radioactive solidified solid added due to the internal device buried therein.
The polymer injection device may include an inline mixer. The inline mixer may include at least one polymer mixing static nozzle 112 replaceable as consumables when the polymer is adhered to the apparatus due to the interruption of power failure.

[Advantageous Effects]

In the method and apparatus according to embodiments of the invention configured as described above, a solidified solid of the radioactive waste is formed by uniformly depositing a polymer throughout the radioactive waste so that leach-resistance and strength of the solidified solid can be significantly increased to thereby enhance safety as compared with solidification of the radioactive waste using boric acid and paraffin.
In addition, as compared with conventional polymer solidification, the method and apparatus according to the embodiments of the invention facilitates hermetic infiltration of a solidification material into various forms of radioactive waste including powdered and granulated radioactive waste through alternate control between polymer injection and vacuum suction to minimize the generation of void gaps inside a solidified waste solid to enhance strength of the solidified solid.
Further, in the method and apparatus according to the embodiments of the invention, unexpected effluent accidents during solidification can be prevented through multiple safeguards, and enables radioactive waste to be safely stored at a lower cost in a disposal site by maximizing waste storage density.

[Description of Drawings]

FIG. 1 illustrates an apparatus for solidification of radioactive waste according to an exemplary embodiment of the present invention.
FIG. 2 is a bottom view of a terminal structure of an internal vacuum suction device according to an exemplary embodiment of the present invention.
FIG. 3 is a side view of a terminal structure of the internal vacuum suction device according to the exemplary embodiment of the present invention.

p: polymer, 110: polymer injection device
111: measuring device, 112: static nozzle
120: solidification drum, 121: internal vacuum suction device
w: radioactive waste, 130: recovery container
131: recovered polymer measuring device, 140: vacuum pump
150: controller

[Best Mode]

The aforementioned and other features and advantages of the invention will become apparent from the following detailed descriptions in conjunction with the accompanying drawings.
FIG. 1 illustrates an apparatus for solidification of radioactive waste according to an exemplary embodiment of the present invention. The apparatus includes a solidification drum 120, a polymer injection device 110, a measuring device 111, an internal vacuum suction device 121, a vacuum pump 140, a controller 150, and a recovery container 130.
The solidification drum 120 accommodates radioactive waste and may be equipped with a shock generator such as a mechanical vibration generator, a microwave generator or an ultrasonic generator, as needed, to serve as an assisting tool for sufficiently infiltrating a polymer into void gaps in the radioactive waste.
The polymer injection device 110 mixes and injects the polymer into the radioactive waste accommodated in the solidification drum 120, and is placed above the solidification drum 120. The polymer injection device 110 may use an inline mixer equipped with a static nozzle to mix a main agent and a hardening agent. The polymer injection device 110 may include two or more static nozzles. The polymer can be injected into the solidification drum 120 while rotating one or two static nozzles, and two to six static nozzles may be used for injecting the polymer. In the case of installing two or more static nozzles, the polymer is uniformly injected through a large number of nozzles, as to reduce polymer injection time and increase polymer injection efficiency made possible because air-bubble generation is reduced under the vacuum effect.
Any type of polymer can be used as long as it exhibits properties of heat resistance and strength to satisfy post-solidification requirements. The polymer may include at least one type of polymer selected among epoxy resin, urethane resin, polyethylene resin, polyester resin, polyvinylchloride resin, polystyrene-divinylbenzene resin, etc.
The measuring device 111 senses the level (height) of the polymer injected into the solidification drum through a distance sensor or the like, which can be mounted onto the polymer injection device 110. The measuring device 111 is connected to the controller 150 and transmits a sensed signal to the controller 150, thereby allowing the controller 150 to properly control the polymer injection device 110 and vacuum pump 140.
At least two measuring devices 111 may be installed as a safeguard against malfunction of any of the measuring devices. The most conservative measured value among the measured values of the measuring devices will be used as input for controlling operation of the polymer injection device and the vacuum pump through the controller 150.
The internal vacuum suction device 121 is inserted at the bottom of the solidification drum filled with powder, particle or various other forms of radioactive waste. The internal vacuum suction device 121 has a tube shape for removing air inside the solidification drum, and may be made from, but not limited to, stainless steel, plastics etc. Further, the internal vacuum suction device 121 is finally buried in a polymer solidified solid inside the solidification drum, and in this case, there is a need to reduce the volume of the internal device in order to decrease the amount of radioactive solidified solid added due to the buried internal vacuum suction device. Therefore, the internal vacuum suction device may have a disc-shaped lower surface, which is brought into close contact with the bottom of the solidification drum by the weight of the waste in the drum in order to make use of the gap between the lower surface of the internal device and the bottom of the solidification drum. The disc-shaped lower surface of the internal device may be formed with multiple projections extending from a central tube or be provided with an air-permeable nonwoven fabric so that a passage for vacuum suction can be formed when the bottom of the internal device comes into close contact with the bottom of the solidification drum.
The recovery container 130, connected to the internal vacuum suction device 121 and the vacuum pump 140, collects the excess polymer flowing out of the solidification drum due to vacuum suction, and ascertains an infiltrated state of the polymer inside the solidification drum. The recovery container 130 may be made of a transparent material or have a transparent window if not transparent so that the amount of recovered polymer can be ascertained through observation. Alternatively, a device for measuring the level of material stored inside the recovery container, for example, a load cell or similar recovered polymer measuring device 131, may be attached.
The recovered polymer measuring device 131 is connected to the controller 150 so that the operations of the vacuum pump and the polymer injection device can be stopped if the amount of polymer recovered into the recovery container exceeds a predetermined amount. As necessary, the recovered polymer measuring device 131 may generate a warning signal.
The vacuum pump 140 is connected to the internal vacuum suction device 121, and degasses the air between the wastes from the solidification drum filled with radioactive waste, thereby enabling hermetic infiltration of the polymer.
The controller 150 processes the sensed signal from the measuring device 111 and controls the operation of the polymer injection device 110 and the vacuum pump 140. A control method of the controller 150 and the process of filling the solidification drum 120 with the polymer are as follows:
First, the solidification drum 120 embedded with the internal vacuum suction device 121 is filled with granulated concentrated waste or radioactive waste of ion-exchange resin, and then the drum is arranged in a preset position. The polymer injection device 110 is mounted on the drum, and both the vacuum pump 140 and the internal vacuum suction device 121 are connected. A polymer main agent from a polymer storage tank and a hardening agent are automatically mixed in an inline mixer, and the mixed polymer is injected into the drum.
The measuring device 111 for measuring the level of the polymer senses the thickness of the polymer laid on the radioactive waste inside the solidification drum. If the sensed level of the polymer is lower than a minimum threshold, the polymer injection device operates and thus the injected polymer is infiltrated into the void gaps in the radioactive waste by gravity. If the sensed level of the polymer is greater than or equal to the minimum threshold and lower than the maximum threshold, both the polymer injection device and the vacuum pump connected to the internal vacuum suction device operates and thus the polymer is infiltrated into the void gaps in the radioactive waste by vacuum suction. If the sensed level of the polymer is greater than or equal to the maximum threshold, the polymer injection device is stopped and only the vacuum pump operates so that the polymer can be gradually infiltrated into the void gaps in the radioactive waste by vacuum suction, thereby preventing excess polymer from being injected into the solidification drum and maintaining an optimal level of polymer injection.
If the polymer is detected by the recovered polymer measuring device 131 of the recovery container 130 after the process of infiltrating the polymer is performed once or more, the polymer injection device 110 and the vacuum pump 140 are manually stopped. At this time, if the process is not manually interrupted by a worker, the recovered polymer measuring device 131 issues a warning based on measurement. Once a set amount is reached or exceeded, the injection device 110 and the vacuum pump 140 are automatically stopped.
The inside of the solidification drum 120 is observed using a closed-circuit television (CCTV) or the like to ascertain the state of the polymer on the waste again. If the ascertained result is satisfactory, the injection device 110 and the internal vacuum suction device 121 are separated from the solidification drum and the solidification drum is closed off with a cap with the internal vacuum suction device left inside the solidification drum. The polymer's reaction to heat is then measured through a temperature sensor, and the drum cap is sealed after a predetermined period of time so as not to interrupt the hardening process.
A method for solidification of radioactive waste according to an exemplary embodiment includes: mixing and injecting a solidification polymer by a polymer injection device into a solidification drum filled various radioactive wastes including powdered and granulated radioactive wastes; gradually infiltrating the polymer into void gaps in the radioactive waste by implementing alternate control between polymer injection and vacuum suction once or more through the polymer injection device and an internal vacuum suction device inserted into at the bottom of the solidification drum; ascertaining an infiltrated state of the polymer inside the solidification drum through a recovery container that is connected to the internal vacuum suction device for ascertaining an infiltrated state of the polymer inside the solidification drum; and burying and solidifying the internal vacuum suction device inside the solidification drum together with the solidified solid.
During infiltration of the polymer, the measuring device for measuring the level of the polymer senses the thickness of the polymer laid on the radioactive waste inside the solidification drum. If the sensed level of the polymer is lower than the minimum threshold, the polymer injection device operates and thus the injected polymer is infiltrated into voids in the radioactive waste by gravity. If the sensed level of the polymer is greater than or equal to the minimum threshold and lower than the maximum threshold, both the polymer injection device and the vacuum pump connected to the internal vacuum suction device operate and thus the polymer is infiltrated into the solidification drum. If the sensed level of the polymer is greater than or equal to the maximum threshold, the polymer injection device stops operating and only the vacuum pump operates so that the polymer can be infiltrated into the void gaps in the radioactive waste through vacuum suction.

[Mode for Invention]

According to an exemplary embodiment, an apparatus for solidification of radioactive waste includes a solidification drum 120, a polymer injection device 110, a measuring device 111, an internal vacuum suction device 121, a vacuum pump 140, a controller 150, and a recovery container 130. In the embodiment, the solidification drum 120 accommodates radioactive waste therein and is equipped with a microwave generator for sufficiently infiltrating a polymer into void gaps in the radioactive waste.
According to the embodiment, the polymer injection device 110 is placed above the solidification drum 120 and injects the polymer into the radioactive waste in the solidification drum 120 while mixing the polymer. The polymer injection device 110 employs an inline mixer having two static nozzles to mix a main agent and a hardening agent. As for the polymer, any epoxy resin may be used so long as the epoxy resin exhibits properties of heat resistance and strength to satisfy post-solidification requirements.
The measuring device 111 senses a level (height) of the polymer injected into the solidification drum through a distance sensor. The measuring device 111 is attached to the polymer injection device 110. The measuring device 111 is connected to the controller 150 and transmits a sensing signal to the controller 150, such that the controller 150 can properly control operation of the polymer injection device 110 and the vacuum pump 140.
In one embodiment, at least two measuring devices 111 are installed as a safeguard against abnormal operation of any of the measuring devices.
According to the embodiment, the internal vacuum suction device 121 is inserted into the bottom of the solidification drum filled with powder, particle or various other forms of radioactive waste. The internal vacuum suction device 121 has a tube shape for removing air inside the solidification drum and is made of stainless steel. The internal device has a disc-shaped lower surface which is brought into close contact with the bottom of the solidification drum by the weight of the waste in the drum; to use the gap between the lower surface of the internal device and the bottom of the solidification drum, and the lower surface of the internal device is formed with multiple radial projections extending from a central tube.
The recovery container 130 is connected to the internal vacuum suction device 121 and the vacuum pump 140. The recovery container 130 collects the excess polymer flowing out of the solidification drum due to vacuum suction, and is made of a transparent material such that the amount of recovered polymer can be ascertained therethrough.
The vacuum pump 140 is connected to the internal vacuum suction device 121 and degasses the air between the wastes from the solidification drum filled with radioactive waste, thereby enabling hermetic infiltration of the polymer.
The controller 150 processes the sensed signal from the measuring device 111 and controls the operation of the polymer injection device 110 and the vacuum pump 140.

[Industrial Applicability]

The present invention is useful for safe handling of radioactive waste by solidifying the radioactive waste at high density.

Claims

A method for solidification of radioactive waste, the method comprising:
mixing and injecting a polymer into a solidification drum filled with radioactive waste using a polymer injection device;

infiltrating the polymer gradually into void gaps in the radioactive waste by implementing alternate control between polymer injection and vacuum suction once or more through the polymer injection device and an internal vacuum suction device inserted at the bottom of the solidification drum filled with the radioactive waste;

ascertaining an infiltrated state of the polymer inside the solidification drum through a recovery container that is connected to the internal vacuum suction device and collects the excess polymer flowing out of the solidification drum; and

burying and solidifying the internal vacuum suction device together with the solidification drum inside the solidification drum after ascertaining that the polymer is completely infiltrated into the radioactive waste inside the solidification drum.
The method of claim 1, wherein the infiltration of the polymer comprises:
operating the polymer injection device to allow the injected polymer to be infiltrated into the void gaps in the radioactive waste by gravity, if a measuring device for measuring a level of the polymer detects that the level of the polymer is lower than the minimum threshold based on measuring the thickness of the polymer laid on the radioactive waste inside the solidification drum;

operating both the polymer injection device and a vacuum pump connected to the internal vacuum suction device to allow the polymer to infiltrate into void gaps in the radioactive waste due to vacuum suction, if the measuring device detects that the level of the polymer is greater than or equal to the minimum threshold and lower than the maximum threshold; and

stopping the polymer injection device while operating only the vacuum pump to allow the polymer to be infiltrated into the void gaps in the radioactive waste due to vacuum suction, if the measuring device detects that the level of the polymer is greater than or equal to the maximum threshold.
The method of claim 1, wherein the mixing and injecting the polymer comprises mixing and injecting the polymer while at least one polymer mixing static nozzle is fixed or rotated in the polymer injection device, at least one polymer mixing static nozzle being a consumable and replaced when the polymer is adhered to the apparatus due to interruption of electric power.
An apparatus for solidification of radioactive waste, comprising:
a solidification drum 120 that accommodates radioactive waste;

a polymer injection device 110 that mixes and injects a polymer into the radioactive waste;

a measuring device 111 that senses a level of the polymer injected into the solidification drum;

an internal vacuum suction device 121 that is inserted at the bottom of the solidification drum filled with the radioactive waste;

a vacuum pump 140 that is connected to the internal vacuum suction device 121;

a controller that processes a sensed signal from the measuring device 111 and controls operation of the polymer injection device 110 and the vacuum pump 140; and

a recovery container, that is connected to the internal vacuum suction device 121, collecting the excess polymer flowing out of the solidification drum, and allowing an infiltrated state of the polymer inside the solidification drum to be ascertained.
The apparatus of claim 4, wherein at least two measuring devices 111 are installed for sensing the level of the polymer injected into the solidification drum as a safeguard against abnormal operation, and the most conservative value between values measured by at least two installed measuring devices is used as input for controlling operation of the polymer injection device and the vacuum pump through the controller 150.
The apparatus of claim 4, further comprising:
a recovered polymer measuring device 131 that is attached to the recovery container, measures the amount of polymer recovered by the recovery container, and generates a warning signal in accordance with the amount of polymer collected in the recovery container,

wherein the recovery container 130 is observed from outside and the controller 150 controls the operation of the vacuum pump and the polymer injection device.
The apparatus of claim 4, wherein the internal vacuum suction device 121 inserted into the bottom of the solidification drum filled with the radioactive waste to be buried in a solidified solid of the radioactive waste has a disc-shaped lower surface formed with multiple grooves or projections or provided with an air-permeable non-woven fabric to make use of the gap between the lower surface of the internal vacuum suction device and the bottom of the solidification drum 120.
The apparatus of claim 4, wherein the polymer injection device comprises an inline mixer, the inline mixer comprising at least one polymer mixing static nozzle as a consumable and replaced when the polymer is adhered to the apparatus due to interruption of electric power.