Apparatus for immobilizing radioactive waste 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 an apparatus for immobilizing radioactive waste contained in a high-integrity container to enhance and improve the storage stability of radioactive waste.

Background Art

[0002] Generally, a high-integrity container for storing radioactive waste is composed of a drum for containing radioactive waste and a lid for sealing the drum. When the radioactive waste is contained in the drum, the lid is placed in a fixed position and coupled to the drum by, for example, a coupling part for sealing the drum. Thereafter, the radioactive waste is charged into the drum through an injection tube.

[0003] Medium- and low-level radioactive waste inevitably generated in the nuclear power industry must ensure safety and integrity suitable for regulatory requirements during handling and disposal, except for extremely low-level radioactive substances. As a method for ensuring the safety and integrity of radioactive substances, there is a method of solidifying or packaging them in a special container, that is, a high-integrity container (HIC), in which safety and integrity have already been ensured.

[0004] Currently, the term "high-integrity container" is not common in most countries except for several countries such as the United States, South Korea, and China. Also, although waste classification and stabilization requirements vary from country to country, it is naturally recognized that a waste container with the concept of maintaining integrity for more than 300 years at a treatment site is necessary.

Summary of the Invention

Problems to be Solved by the Invention

[0005] A high-integrity container is defined as a radioactive waste packaging container that can maintain integrity for more than 300 years under general underground environments and disposal conditions in South Korea. The target waste is concentrated waste liquid dry powder, dry waste resin, and solidified bodies of concentrated waste liquid and waste resin.

[0006] The problem to be solved by the present invention is to enhance the safety of the dry concentrated waste liquid and waste resin contained in a highly sound container. That is, the present invention aims to immobilize and seal the upper part of the contained radioactive waste so as to prevent the radioactive waste from flowing out to the outside in the event of an accident such as the dropping of the highly sound container or the damage of the lid.

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

Means for Solving the Problems

[0008] The radioactive waste immobilization device according to an embodiment of the present invention for achieving the above problems is for immobilizing the upper part of the radioactive waste in the highly sound container in order to prevent the radioactive waste contained in the highly sound container from flowing out to the outside, and includes a polymer resin injection part for injecting a polymer resin for immobilization onto the radioactive waste contained in the highly sound container to form a polymer resin layer, a polymer resin sensing part for measuring the laminated thickness of the polymer resin layer and adjusting the injection amount of the polymer resin, and a photocuring part for curing the polymer resin layer.

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

[0010] The polymer resin sensing part may measure a plurality of laminated thicknesses of the polymer resin layer and adjust the injection amount of the polymer resin with the average value thereof.

[0011] When the measurement result of the polymer resin sensing part, the average value, is not suitable for a preset laminated thickness, the polymer resin injection part may further inject the polymer resin.

[0012] The photocuring part may rotate on the polymer resin layer in order to uniformly cure the polymer resin layer.

[0013] The photocuring part can rotate with reference to the center of the high-integrity container.

[0014] Another embodiment of the method for immobilizing radioactive waste according to the present invention for achieving the above object is for immobilizing the upper part of the radioactive waste in the high-integrity container in order to prevent the radioactive waste loaded in the high-integrity container from flowing out to the outside, and may include: a) injecting an immobilizing polymer resin onto the radioactive waste loaded in the high-integrity container to form a polymer resin layer; b) measuring the laminated thickness of the polymer resin layer to adjust the injection amount of the polymer resin; and c) curing the polymer resin layer.

[0015] Adjusting the injection amount of the polymer resin in step b) may measure a plurality of the laminated thicknesses of the polymer resin layer and adjust the injection amount of the polymer resin with the average value thereof.

[0016] When the average value is not suitable for a preset laminated thickness, the polymer resin may be further injected.

[0017] Step c) of curing the polymer resin layer may be repeatedly performed.

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

Advantages of the Invention

[0019] According to the present invention, there are provided an apparatus for immobilizing radioactive waste for immobilizing and sealing the upper part of the loaded radioactive waste, which can prevent the radioactive waste from flowing out to the outside in the event of an accident such as the dropping of a high-integrity container or the damage of a lid, and a method for immobilizing radioactive waste using the same.

Brief Description of the Drawings

[0020]

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Best Mode for Carrying Out the Invention

[0021] In order to prevent the radioactive waste loaded in the highly integrity container from flowing out to the outside, the present invention provides an apparatus for immobilizing the upper part of the radioactive waste in the highly integrity container. The apparatus includes a polymer resin injection part that injects a polymer resin for immobilization onto the radioactive waste loaded in the highly integrity container to form a polymer resin layer, a polymer resin sensing part that measures the laminated thickness of the polymer resin layer and adjusts the injection amount of the polymer resin, and a photocuring part that cures the polymer resin layer.

Mode for Carrying Out the Invention

[0022] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The advantages and features of the present invention, and the methods for achieving them, will become clear by referring to the embodiments described in detail hereinafter together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and can be realized in various different forms. The present embodiment is merely to complete the disclosure of the present invention and is provided to fully inform those with ordinary knowledge in the technical field to which the present invention belongs of the scope of the invention. The present invention is defined only by the scope of the claims. The same reference numerals throughout the specification refer to the same components.

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

[0024] FIG. 1 is a flowchart showing an immobilization method for radioactive waste according to an embodiment of the present invention, FIG. 2 is a diagram showing an example of radioactive waste loaded in a high-integrity container, FIG. 3 is a diagram showing that a polymer resin injection unit injects a polymer resin onto the upper part of the radioactive waste, FIG. 4 is a diagram showing that a polymer resin sensing unit measures the thickness of the polymer resin layer, FIG. 5 is a diagram showing that a photo-curing unit cures 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 plan view of an immobilization device for radioactive waste according to an embodiment of the present invention.

[0025] Referring to FIG. 2, the radioactive waste 12 is loaded and stored in the high-integrity container 10.

[0026] The radioactive waste 12 can be concentrated waste liquid dry powder, dry waste resin, or a solidified body of concentrated waste liquid and waste resin, but is not limited as long as it is waste generated in 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 under general underground environments and disposal conditions in Korea. The high-integrity container 10 can be configured in a combined form of a cylindrical drum and a lid that is located at the upper central part of the drum and seals the drum. An opening is formed at the upper central part of the drum so that radioactive waste can be loaded.

[0028] When examining the high-integrity container 10, the outside of the drum can be surrounded by, for example, stainless steel or carbon steel in order 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 with a thickness of 1 mm to 5 mm. Note that the high-integrity container 10 can also be formed of a concrete material.

[0029] Referring to FIG. 7, the radioactive waste immobilization device 100 according to an embodiment of the present invention is for immobilizing the upper part of the radioactive waste 12 in the highly reliable container 10 in order to prevent the radioactive waste 12 loaded in the highly reliable container 10 from flowing out to the outside.

[0030] The radioactive waste immobilization device 100 according to an embodiment of the present invention may include a main body 101, a polymer resin injection part 110 attached to the main body 101, a polymer resin sensing part 120 attached to the main body 101, and a photocuring part 130 attached to the central part of the main body 101.

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

[0032] The main body 101 may include a polymer resin storage part for storing the polymer resin injected into the highly reliable container 10 inside. Further, the main body 101 may include a control part for controlling the polymer resin injection part 110 and the polymer resin sensing part 120.

[0033] The main body 101 can be formed in a circular shape. The shape of the main body 101 is formed in a circular shape so as to easily overlap with the upper part of the cylindrical highly reliable container 10, but the shape of the main body 101 is not limited thereto.

[0034] The polymer resin injection part 110 is attached to the main body 10. The polymer resin injection part 110 receives the supply of the polymer resin from the above-mentioned polymer resin storage part and can inject the polymer resin into the highly reliable container 10. For this purpose, the polymer resin injection part 110 may include a discharge nozzle for discharging the polymer resin into the highly reliable container 10. The polymer resin injection part 110 may be located overlapping the upper opening of the highly reliable container 10.

[0035] Referring to FIG. 3, the polymer resin discharged from the polymer resin injection part 110 is injected into the upper part on the radioactive waste 12. When injected for a certain period of time, the polymer resins are laminated to form a polymer resin layer 51. That is, the polymer resin injection part 110 can form the polymer resin layer 51 by injecting the immobilizing polymer resin onto the radioactive waste 12 loaded in the highly sound container 10.

[0036] The polymer resin can be formed of a photocurable resin. The polymer resin can include an acrylate-based oligomer, monomer, photoinitiator, and additives that complement other physical properties. The acrylate-based oligomer can be one selected from urethane-based, epoxy-based, ester-based, ether-based, or silicon-based. Preferably, polyurethane acrylate produced by reacting diisocyanate, polyol, and methacrylate is preferably used.

[0037] More specifically, the essential components of the oligomer can be mixed in a predetermined ratio with either one of the base raw materials of polycarbonate type urethane acrylate and polyester type urethane acrylate, a monomer bonded with a polymer chain of a polymer to improve the adhesiveness and fixing property between the oligomer and the radioactive waste 12, and a photoinitiator that promotes cross-linking of the base raw material.

[0038] Among the base raw materials, urethane acrylate is a mixture of urethane (-NHCOO-) and acrylate (-OCOHC=CH2) for moldability and crack prevention. Epoxy acrylates and polyester acrylates can be further added to complement the disadvantages of urethane acrylate in terms of heat resistance and adhesiveness.

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

[0040] The photoinitiator can enable the oligomer to initiate a polymerization or polymerization reaction to form a cross link on radioactive waste 12 and adhere to solidification. As a means to promote the UV polymerization reaction to improve the adhesiveness and fixability of the oligomer, any one of alpha hydroxy ketones, phenyl glyoxylate, and phosphine oxide can be used.

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

[0042] Referring to FIG. 4, the polymer resin sensing unit 120 can measure the lamination thickness of the polymer resin layer 51 a plurality of times and adjust the injection amount of the polymer resin based on the average value thereof. Specifically, after the polymer resin sensing unit 120 measures the thickness of various portions of the polymer resin layer 51 to obtain thickness values, it determines the thickness of the polymer resin layer 51 formed based on the average of the obtained thickness values.

[0043] If the measurement result of the polymer resin sensing unit 120, i.e., the average value of the thickness, is not suitable for 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. Thereby, the polymer resin injection unit 110 can further inject the polymer resin into the highly reliable container 10. Thereafter, when the polymer resin sensing unit 120 measures the thickness of the polymer resin layer 51 and the thickness of the formed polymer resin layer 51 is suitable for the preset thickness, no additional injection of the polymer resin is performed.

[0044] That is, when the polymer resin is injected into the highly reliable 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. When the thickness of the polymer resin layer is not suitable for the set value, further injection of the polymer resin is performed. When the thickness of the polymer resin layer is suitable for the set value, the injection of the polymer resin is interrupted and the formed polymer resin layer is cured.

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

[0046] Referring to FIG. 5, the photocuring 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 for rotating the rotating shaft 132.

[0047] Note that the photocuring unit 130 can rotate on the polymer resin layer 51 in order to cure the polymer resin layer 51 uniformly. That is, when the rotation axis 132 of the photocuring unit 130 rotates, the UV irradiation unit 131 coupled to one end of the rotation axis 132 can also rotate. Due to the rotation of the UV irradiation unit 131, the polymer resin layer 51 can be cured uniformly. At this time, the rotation axis 132 rotates with reference to the center of the highly robust container 10. Therefore, the UV irradiation unit 131 also rotates with reference to the center of the highly robust container 10. That is, the photocuring unit 130 can rotate as a whole with reference to the center of the highly robust container.

[0048] Specifically, when the polymer resin layer 51 is irradiated with UV by the UV irradiation unit 131 of the photocuring unit 130 and the photoinitiator starts a polymerization or polymerization reaction, the polymer resin layer 51 is cured uniformly and steadily by the UV curing mechanism.

[0049] That is, the polymer resin layer 51 is UV-cured to form cross-links and be fixed to solidify by the UV curing mechanism of free radical polymerization. Here, the UV irradiation unit 131 can be any one of a metal lamp, a mercury lamp, and an LED lamp.

[0050] Note that the photocuring process can be repeated several times for the immobilization of the polymer resin layer 51.

[0051] Next, with reference to FIGS. 1 to 6, a method for immobilizing radioactive waste according to an embodiment of the present invention will be described. The method for immobilizing radioactive waste of the present invention is for immobilizing the upper part of the radioactive waste in the highly robust container in order to prevent the radioactive waste loaded in the highly robust container from flowing out to the outside.

[0052] Referring to FIGS. 1 and 3, an immobilization polymer resin is injected onto the radioactive waste 12 loaded in the high integrity container 10 to form a polymer resin layer 51 (S10). The injection of the polymer resin is performed through the polymer resin injection unit 110 described above. Since the polymer resin layer is substantially the same as the polymer resin described above, overlapping descriptions are omitted.

[0053] Subsequently, referring to FIGS. 1 and 4, the laminated thickness of the polymer resin layer 51 can be measured to adjust the injection amount of the polymer resin (S20). The adjustment of the thickness of the polymer resin layer 51 is performed by the polymer resin sensing unit 120 described above.

[0054] Adjusting the injection amount of the polymer resin in the step S20 can measure the laminated thicknesses of a plurality of polymer resin layers 51 and adjust the injection amount of the polymer resin with the average value thereof. More specifically, when the average value is not suitable for a preset laminated thickness, the polymer resin can be further injected. On the contrary, when the average value is suitable for a preset laminated thickness, the additional injection of the polymer resin can be interrupted.

[0055] Subsequently, referring to FIGS. 1 and 5, a step of curing the polymer resin layer 51 is performed (S30). The step S30 of curing the polymer resin layer 51 can be repeatedly performed. By this step, the polymer resin layer formed by the injection of the polymer resin can be immobilized. Thereby, the formation of the polymer resin layer 51 for immobilizing the radioactive waste 12 can be completed (see FIG. 6). By the formation of the polymer resin layer 51, the upper part of the radioactive waste 12 can be sealed from the outside in 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 immobilized by the polymer resin. Thereby, the storage safety for the radioactive waste can be strengthened and improved. In particular, in the event of an accident such as the dropping of the high integrity container or the damage of the lid, it is possible to prevent the radioactive waste from flowing out to the outside.

[0057] While the embodiments of the present invention have been described with reference to the above and the attached drawings, those having ordinary knowledge in the technical field to which the present invention pertains can understand that the present invention can be implemented in other specific forms without changing its technical idea and essential features. Therefore, it must be understood that the above-described embodiment is illustrative in all respects and not restrictive.

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 immobilization 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 adjusting 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 device of claim 1, wherein the polymeric resin comprises an acrylate-based oligomer, a monomer, and a photoinitiator.

3. The polymer resin sensing unit measures the lamination thickness of a plurality 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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