Radioactive waste immobilization device and immobilization method using the same

Abstract

A radioactive waste immobilization device and a method for immobilizing radioactive waste using the same, which immobilize radioactive waste loaded in a high integrity container to enhance storage safety of the radioactive waste, are disclosed. The radioactive waste immobilization device according to an embodiment of the present invention is for immobilizing an upper portion of the radioactive waste in the high integrity container to prevent the radioactive waste loaded in the high integrity container from leaking out, and may include a polymer resin injection unit that injects a polymer resin for immobilization onto the radioactive waste loaded in the high integrity container to form a polymer resin layer, a polymer resin sensing unit that measures a layer thickness of the polymer resin layer to adjust the injection amount of the polymer resin, and a light curing unit that hardens the polymer resin layer.

Description

[Technical field]

[0001] The present invention relates to a radioactive waste immobilization device for immobilizing radioactive waste placed in a high integrity container to strengthen and improve the storage stability of the radioactive waste. [Background technology]

[0002] Typically, a high integrity container for the storage of radioactive waste consists of a drum containing the radioactive waste and a lid that seals said drum. Once the radioactive waste is contained in the drum, the lid is put into place and connected to the drum, for example by a connection that seals the drum. The radioactive waste is then loaded into the drum via an injection tube.

[0003] The nuclear industry inevitably generates low and medium level radioactive waste, except for extremely low level radioactive materials, and the handling and disposal of such waste must be handled and disposed of in a manner that meets the safety and integrity requirements of the relevant regulations. Methods for ensuring the safety and integrity of radioactive materials include solidifying them or packaging them in special containers that have already been certified as safe and sound, i.e., High Integrity Containers (HICs).

[0004] Currently, the term "high integrity container" itself is not common in most countries except for a few countries such as the United States, South Korea, and China. In addition, waste classification and stabilization requirements differ from country to country, but it is generally recognized that waste containers that maintain their integrity for more than 300 years at treatment plants are necessary. Summary of the Invention [Problem to be solved by the invention]

[0005] A high-integrity container is defined as a radioactive waste packaging container that can maintain its integrity for more than 300 years in Korea's general underground environment and disposal conditions. The target wastes are concentrated liquid waste dry powder, dried waste resin, and concentrated liquid waste and waste resin solidified bodies.

[0006] The problem to be solved by the present invention is to enhance the safety of the dried concentrated waste liquid and waste resin charged in a high integrity container. That is, the present invention aims to fix and seal the upper part of the charged radioactive waste so that the radioactive waste can be prevented from leaking out in the event of an accident such as the dropping of the high integrity container or damage to the lid.

[0007] The objects of the present invention are not limited to the objects mentioned above, and other objects not mentioned herein will be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0008] To achieve the above object, a radioactive waste immobilization device according to an embodiment of the present invention is for immobilizing an upper portion of the radioactive waste in a high-integrity container to prevent the radioactive waste loaded in the high-integrity container from possibly leaking out, and may include a polymer resin injection unit that injects a polymer resin for immobilization onto the radioactive waste loaded in the high-integrity container to form a polymer resin layer, a polymer resin sensing unit that measures a layer thickness of the polymer resin layer to adjust the amount of the polymer resin injected, and a photocuring unit that hardens the polymer resin layer.

[0009] The polymer resin may include an acrylate-based oligomer, a monomer, and a photoinitiator.

[0010] The polymer resin sensing unit may measure the thickness of the polymer resin layer at a plurality of times and adjust the amount of the polymer resin to be injected based on the average value of the measured thicknesses.

[0011] When the average value measured by the polymer resin sensing unit does not match the preset layer thickness, the polymer resin injecting unit may further inject the polymer resin.

[0012] The light curing unit may rotate on the polymer resin layer to uniformly cure the polymer resin layer.

[0013] The light curing unit may rotate about the center of the high integrity container.

[0014] To achieve the above object, a method for immobilizing radioactive waste according to another embodiment of the present invention is for immobilizing an upper portion of the radioactive waste in a high-integrity container to prevent the radioactive waste loaded in the high-integrity container from possibly leaking out, and may include a) a step of injecting a polymer resin for immobilization onto the radioactive waste loaded in the high-integrity container to form a polymer resin layer, b) a step of measuring a layer thickness of the polymer resin layer and adjusting the amount of the polymer resin injected, and c) a step of hardening the polymer resin layer.

[0015] In the step b), the amount of the polymer resin injected may be adjusted by measuring the thickness of the polymer resin layer multiple times and adjusting the amount of the polymer resin injected based on the average value of the measured thicknesses.

[0016] If the average value does not fit the pre-set layer thickness, the polymer resin may be further injected.

[0017] Step c) of curing the polymeric resin layer may be repeated.

[0018] Specific details of other embodiments are included in the detailed description and drawings. Effect of the Invention

[0019] According to the present invention, there is provided a radioactive waste immobilization device that immobilizes and seals the upper part of the loaded radioactive waste, and that can prevent radioactive waste from leaking out in the event of an accident such as the fall of a high-integrity container or damage to the lid, and a method of immobilization using the same. [Brief description of the drawings]

[0020] [Figure 1] 1 is a flow chart illustrating a method for immobilizing radioactive waste according to an embodiment of the present invention. [Diagram 2]FIG. 1 shows an example of radioactive waste loaded into a high integrity container. [Diagram 3] FIG. 13 is a diagram showing the polymer resin injection section injecting polymer resin into the top of the radioactive waste. [Figure 4] FIG. 13 is a diagram showing the polymer resin sensing unit measuring the thickness of a polymer resin layer. [Diagram 5] FIG. 13 is a diagram showing the light curing unit curing the polymer resin layer. [Figure 6] FIG. 2 is a diagram showing a polymer layer for immobilizing radioactive waste formed on radioactive waste. [Figure 7] FIG. 2 is a plan view of a radioactive waste immobilization device according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THEINVENTION

[0021] The present invention relates to an apparatus for immobilizing an upper portion of radioactive waste in a high-integrity container to prevent the radioactive waste loaded in the high-integrity container from leaking out, the apparatus comprising: a polymer resin injection unit for injecting a polymer resin for immobilization onto the radioactive waste loaded in the high-integrity container to form a polymer resin layer; a polymer resin sensing unit for measuring a layer thickness of the polymer resin layer to adjust the amount of the polymer resin injected; and a light curing unit for curing the polymer resin layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, as well as methods for achieving the same, will become apparent from the following detailed embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be realized in various different forms. The present embodiments are provided merely to complete the disclosure of the present invention and to fully inform those skilled in the art of the present invention of the scope of the invention, and the present invention is defined only by the scope of the claims. The same reference symbols refer to the same elements throughout the specification.

[0023] Hereinafter, a radioactive waste immobilization device and a radioactive waste immobilization method using the same according to an embodiment of the present invention will be described.

[0024] FIG. 1 is a flowchart showing a method for immobilizing radioactive waste according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of radioactive waste loaded into a high-integrity container, FIG. 3 is a diagram showing a polymer resin injection unit injecting polymer resin onto the top of the radioactive waste, FIG. 4 is a diagram showing a polymer resin sensing unit measuring the thickness of the polymer resin layer, FIG. 5 is a diagram showing a photocuring unit curing the polymer resin layer, FIG. 6 is a diagram showing a polymer layer for immobilizing radioactive waste formed on the radioactive waste, and FIG. 7 is a diagram showing a plan view of an apparatus for immobilizing radioactive waste according to an embodiment of the present invention.

[0025] Referring to FIG. 2, radioactive waste 12 is placed in a high integrity container 10 for storage.

[0026] The radioactive waste 12 may be a dried powder of concentrated waste liquid, dried waste resin, or a solidified body of concentrated waste liquid and waste resin, but is not limited thereto as long as it is waste generated at a nuclear power plant.

[0027] The high integrity container 10 can be defined as a radioactive waste packaging container that can maintain its integrity for more than 300 years in typical underground environments and disposal conditions in Korea. The high integrity container 10 can be configured in the form of a combination of a cylindrical drum and a lid that is located at the center of the upper part of the drum and seals the drum. An opening is formed at the center of the upper part of the drum so that radioactive waste can be loaded into it.

[0028] Regarding the high integrity container 10, the outside of the drum may be surrounded by, for example, stainless steel or carbon steel to reinforce the impact strength of the high integrity container 10 against external impacts. In this case, it is preferable to use stainless steel or carbon steel having a thickness of 1 mm to 5 mm. The high integrity container 10 may also be made of concrete.

[0029] Referring to FIG. 7, a radioactive waste immobilization device 100 according to an embodiment of the present invention is intended to immobilize the upper part of the radioactive waste 12 in the high integrity container 10 in order to prevent the radioactive waste 12 loaded in the high integrity container 10 from possibly leaking out.

[0030] A radioactive waste immobilization device 100 according to an embodiment of the present invention may include a main body 101, a polymer resin injection unit 110 mounted on the main body 101, a polymer resin sensing unit 120 mounted on the main body 101, and a light curing unit 130 mounted in the center of the main body 101.

[0031] The main body 101 is placed on the upper part of the high integrity container 10. When the immobilization work of the radioactive waste 12 is completed, the radioactive waste immobilization device 100 is separated from the upper part of the high integrity container 10. Then, the radioactive waste immobilization device 100 can be placed on another high integrity container 100 where the immobilization work is being performed.

[0032] The main body 101 may include a polymer resin storage unit therein for storing polymer resin to be injected into the high integrity container 10. The main body 101 may also include a control unit for controlling the polymer resin injection unit 110 and the polymer resin sensing unit 120.

[0033] The main body 101 may be formed in a circular shape. The main body 101 is formed in a circular shape so that it can be easily overlapped with the upper part of the cylindrical high integrity container 10, but the shape of the main body 101 is not limited thereto.

[0034] The polymer resin injecting unit 110 is attached to the main body 10. The polymer resin injecting unit 110 can receive a supply of polymer resin from the above-mentioned polymer resin storage unit and inject the polymer resin into the high integrity container 10. To this end, the polymer resin injecting unit 110 can include a discharge nozzle that discharges the polymer resin into the high integrity container 10. The polymer resin injecting unit 110 can be positioned to overlap with an upper opening of the high integrity container 10.

[0035] 3, the polymer resin discharged from the polymer resin injector 110 is injected into the upper portion above the radioactive waste 12, and after being injected for a certain period of time, the polymer resin is layered to form a polymer resin layer 51. That is, the polymer resin injector 110 can form the polymer resin layer 51 by injecting the polymer resin for fixation onto the radioactive waste 12 loaded in the high integrity container 10.

[0036] The polymer resin may be a photocurable resin. The polymer resin may include an acrylate oligomer, a monomer, a photoinitiator, and additives that complement other physical properties. The acrylic oligomer may be one selected from urethane, epoxy, ester, ether, and silicone. It is preferable to use polyurethane acrylate prepared by reacting diisocyanate, polyol, and methacrylate.

[0037] More specifically, the essential components of the oligomer may be a base material selected from the group consisting of polycarbonate-type urethane acrylate and polyester-type urethane acrylate, a monomer that bonds to a polymer chain to improve adhesion and fixation between the radioactive waste 12, and a photoinitiator that promotes cross-linking of the base material, which may be mixed in a predetermined ratio.

[0038] Of the base materials, urethane acrylate is a mixture of urethane (-NHCOO-) and acrylate (-OCOHC=CH2) for moldability and crack prevention, and epoxy acrylates and polyester acrylates can be added to compensate for the shortcomings of urethane acrylate in heat resistance and adhesion.

[0039] In addition, the monomer can improve adhesion, spreadability, and workability by increasing the polymerization reaction rate on the radioactive waste 12 by adjusting the viscosity of the oligomer, and can play an important role in water resistance, moldability, dimensional stability during thermoforming, heat resistance, tear resistance, thermal shock stability, and high temperature and humidity stability. The monomer may be any one of monofunctional acrylates, difunctional acrylates, trifunctional acrylates, and multifunctional acrylates.

[0040] The photoinitiator can initiate a polymerization reaction of the oligomer to form cross links on the radioactive waste 12 and solidify it. Any one of alpha hydroxy ketones, phenyl glyoxylate, and phosphine oxide can be used to accelerate the UV polymerization reaction to improve the adhesion and fixation of the oligomer.

[0041] The polymer resin sensing unit 120 is mounted on the main body 101. The polymer resin sensing unit 120 can adjust the injection amount of the polymer resin by measuring the laminated thickness of the polymer resin layer 51. The polymer resin sensing unit 120 can measure the thickness of the polymer resin layer 51 by a laser distance measurement method.

[0042] 4, the polymer resin sensing unit 120 measures a plurality of lamination thicknesses of the polymer resin layer 51 and adjusts the injection amount of the polymer resin based on the average value of the measurements. Specifically, the polymer resin sensing unit 120 measures the thicknesses of various portions of the polymer resin layer 51 to obtain thickness values, and then determines the thickness of the formed polymer resin layer 51 based on the average of the obtained thickness values.

[0043] If the average thickness measured by the polymer resin sensing unit 120 does not match the preset lamination thickness, it is necessary to form the polymer resin layer 51 thicker. In this case, the control unit of the main body 101 starts the operation of the polymer resin injection unit 110. This allows the polymer resin injection unit 110 to inject more polymer resin into the high integrity container 10. Thereafter, the polymer resin sensing unit 120 measures the thickness of the polymer resin layer 51, and if the thickness of the formed polymer resin layer 51 matches the preset thickness, no additional injection of polymer resin is performed.

[0044] That is, when the polymer resin is injected into the high integrity container 10 by the polymer resin injection unit 110 to form the polymer resin layer 51, the polymer resin sensing unit 120 measures the thickness of the polymer resin layer 51, and if the thickness of the polymer resin layer does not match the set value, further polymer resin is injected, and if the thickness of the polymer resin layer matches the set value, the injection of the polymer resin is interrupted and the formed polymer resin layer is hardened.

[0045] The light curing unit 130 is attached to the main body 101. The light curing unit 130 cures the polymer resin layer 51.

[0046] 5, the light curing unit 130 may include a UV irradiation unit 131 and a rotating shaft 132. The UV irradiation unit 131 is coupled to one end of the rotating shaft 132, and the other end of the rotating shaft 132 is coupled to the main body 101. In this case, the main body 101 may include a driving unit that rotates the rotating shaft 132.

[0047] In addition, the light curing unit 130 can rotate on the polymer resin layer 51 in order to uniformly cure the polymer resin layer 51. That is, when the rotation shaft 132 of the light curing unit 130 rotates, the UV irradiation unit 131 coupled to one end of the rotation shaft 132 can also rotate. The rotation of the UV irradiation unit 131 can uniformly cure the polymer resin layer 51. At this time, the rotation shaft 132 rotates with the center of the high integrity container 10 as a reference. Therefore, the UV irradiation unit 131 also rotates with the center of the high integrity container 10 as a reference. That is, the light curing unit 130 can rotate as a whole with the center of the high integrity container as a reference.

[0048] Specifically, when the polymer resin layer 51 is irradiated with UV by the UV irradiator 131 of the photo-curing unit 130 and the photoinitiator starts a polymerization reaction, the polymer resin layer 51 is cured uniformly and consistently by the UV curing mechanism.

[0049] That is, cross links are formed in the polymer resin layer 51 through a UV curing mechanism of free radical polymerization, and the polymer resin layer 51 is UV cured so as to be solidified and fixed. Here, the UV irradiator 131 may be any one of a metal lamp, a mercury lamp, and an LED lamp.

[0050] The photocuring step can be repeated several times to fix the polymer resin layer 51 .

[0051] Next, a method for immobilizing radioactive waste according to an embodiment of the present invention will be described with reference to Figures 1 to 6. The method for immobilizing radioactive waste according to the present invention is for immobilizing the upper part of the radioactive waste in a highly-integral container in order to prevent the radioactive waste placed in the highly-integral container from leaking out.

[0052] 1 and 3, a polymer resin for immobilization is injected onto the radioactive waste 12 placed in a high integrity container 10 to form a polymer resin layer 51 (S10). The polymer resin is injected through the above-mentioned polymer resin injection unit 110. The polymer resin layer is substantially the same as the above-mentioned polymer resin, and therefore a duplicated description will be omitted.

[0053] 1 and 4, the amount of polymer resin injected can be adjusted by measuring the thickness of the polymer resin layer 51 (S20). The thickness of the polymer resin layer 51 is adjusted by the polymer resin sensing unit 120 described above.

[0054] In the step S20, the injection amount of the polymer resin may be adjusted by measuring a plurality of stacking thicknesses of the polymer resin layer 51 and adjusting the injection amount of the polymer resin based on the average value of the measured stacking thicknesses. More specifically, if the average value does not match the preset stacking thickness, the polymer resin may be further injected. On the other hand, if the average value matches the preset stacking thickness, the additional injection of the polymer resin may be stopped.

[0055] Continuing to refer to FIG. 1 and FIG. 5, a step of hardening the polymer resin layer 51 is performed (S30). The step of hardening the polymer resin layer 51, S30, can be repeated. This step allows the polymer resin layer formed by injecting the polymer resin to be fixed. This completes the formation of the polymer resin layer 51 for fixing the radioactive waste 12 (see FIG. 6). With the formation of the polymer resin layer 51, the upper part of the radioactive waste 12 can be sealed from the outside within the high integrity container 10.

[0056] According to the present invention, the upper part of the radioactive waste 12 loaded in the high integrity container 10 can be fixed by polymer resin. This strengthens and improves the safety of storing the radioactive waste. In particular, it is possible to prevent the radioactive waste from leaking out in the event of an accident such as the dropping of the high integrity container or damage to the lid.

[0057] Although the embodiment of the present invention has been described above with reference to the accompanying drawings, those skilled in the art will understand that the present invention can be embodied in other specific forms without changing the technical idea or essential features of the present invention. Therefore, it should be understood that the above embodiment is illustrative in all respects and is not limiting.

Claims

1. 1. An apparatus for immobilizing an upper portion of radioactive waste in a highly-integral container to prevent the radioactive waste contained in the highly-integral container from leaking out, comprising: a polymer resin injection section for injecting a polymer resin for fixation onto the radioactive waste placed in the high integrity container to form a polymer resin layer; a polymer resin sensing unit for measuring a thickness of the polymer resin layer and controlling an injection amount of the polymer resin; A radioactive waste immobilization device including a light curing unit that cures the polymer resin layer.

2. 2. The radioactive waste immobilization apparatus of claim 1, wherein the polymeric resin comprises an acrylate-based oligomer, a monomer, and a photoinitiator.

3. The polymer resin sensing unit measures a plurality of the lamination thicknesses of the polymer resin layers, 2. The apparatus for immobilizing radioactive waste according to claim 1, wherein the amount of the polymer resin injected is adjusted based on these average values.

4. If the average value of the measurement result of the polymer resin sensing unit does not match the preset lamination thickness, 4. The radioactive waste immobilization apparatus according to claim 3, wherein the polymer resin injector further injects the polymer resin.

5. 2. The radioactive waste immobilization device according to claim 1, wherein the light curing unit rotates on the polymer resin layer to uniformly harden the polymer resin layer.

6. 6. The radioactive waste immobilization device according to claim 5, wherein the light hardening unit rotates about the center of the high integrity container.

7. 1. A method for immobilizing an upper portion of a highly-integral container of radioactive waste in order to prevent the radioactive waste contained in the highly-integral container from possibly leaking out, comprising: a) injecting a polymer resin for immobilization onto the radioactive waste placed in the high integrity container to form a polymer resin layer; b) measuring a thickness of the polymer resin layer to adjust the amount of the polymer resin injected; c) curing said polymeric resin layer.

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