KR20210093054A - Borosilicate glass solid and the mehtod of manufacturing the same - Google Patents

Abstract

According to an embodiment of the present invention, a glass solidification agent comprises the following steps of: preparing glass medium powder including borosilicate glass and an inorganic adsorbent; preparing a mixture by mixing radioactive waste with the glass medium powder; melting the mixture to manufacture melt; and obtaining a solidified object by quenching the melt. Therefore, the present invention is increase acceptability of radioactive repositories.

Description

Borosilicate glass solidified body and its manufacturing method {BOROSILICATE GLASS SOLID AND THE MEHTOD OF MANUFACTURING THE SAME}

The present disclosure relates to a borosilicate glass solidified body and a method for manufacturing the same. Specifically, the present disclosure relates to a borosilicate glass solidified body of a new composition for stable solidification of an inorganic adsorbent (Cancrinite) that has adsorbed low and medium level radioactive waste, and a method for manufacturing the same.

After the decommissioning of Kori Unit 1, the exhausted domestic nuclear power plants are scheduled to be dismantled sequentially, and the amount of waste generated in the decontamination/decommissioning process is expected to increase exponentially. Among these, existing domestic low- and medium-level radioactive waste disposal sites are limited to 800,000 drums, so it is expected that it will be difficult to accommodate both nuclear dismantling and operating wastes in the future if waste volume reduction technology is not secured. Therefore, along with the development of decontamination technology for nuclear power plants, efficient removal, immobilization of radionuclides from the waste liquid generated after decontamination, and a study on the suitability of radioactive waste disposal are required.

When decommissioning a nuclear power plant, it is expected that the primary system will preferentially perform chemical decontamination to reduce waste volume and manage workers' coverings. However, when an ion exchange resin is used, about 4,500 L of organic waste is generated, and there are many difficulties in disposing of such organic waste. In addition, ion exchange resins cannot satisfy volume increase and disposal suitability during cement solidification due to their moisture absorption and swelling characteristics, so they are currently stored in high-quality containers in Korea. However, high-quality containers are expensive, and organic resins have disadvantages in that they can generate gas due to microbial growth and radiation decomposition during long-term disposal. Therefore, recently, research on inorganic materials (Zeolite-based) rather than organic materials as ion exchange resins has been actively conducted.

The present disclosure aims to recognize the above problems and provide a method for solidifying a Cancrinite adsorbent among inorganic ion exchange resins and to provide evaluation thereof.

The present disclosure is to develop a borosilicate glass solidified body of a new composition capable of physically and chemically solidifying an inorganic adsorbent, which is a material that replaces an existing ion exchange resin disposed in an expensive high-quality container, and to provide a method for manufacturing the same. .

The present disclosure aims to improve the solubility of radioactive repositories by stably solidifying Cancrinite among inorganic adsorbents physically and chemically, and thereby reducing the volume of low and medium level radioactive waste.

The glass solidified body of one embodiment of the present disclosure includes a glass medium including borosilicate glass (borosilicate glass) and an inorganic adsorbent, and radioactive waste, and the borosilicate glass is SiO ₂ , B ₂ O ₃ , Li ₂ O, CaO may be included.

The glass medium may include borosilicate glass and inorganic adsorbent in a weight ratio of borosilicate glass:inorganic adsorbent in a weight ratio of 1:9 to 5:5.

The borosilicate glass is based on 100% by weight of the total borosilicate glass, SiO ₂ : 30 to 35% by weight, B ₂ O ₃ : 50 to 60% by weight, Li ₂ O: 3 to 8% by weight, CaO: 3 to 8% by weight , may include

The inorganic adsorbent may be a zeolite.

The inorganic adsorbent may be Cancrinite.

_{The inorganic adsorbent may include SiO 2} : 35 to 45 wt% Al ₂ O ₃ : 28 to 38 wt% Na ₂ O: 22 to 32 wt% based on 100 wt% of the total inorganic adsorbent.

The radioactive waste is medium and low-level radioactive waste, at least one oxide selected from the group consisting of iron (Fe), chromium (Cr), cesium (Cs), nickel (Ni), cobalt (Co) and manganese (Mn). can

The radioactive waste may be included in an amount of 0.1 to 0.5% by weight based on 100% by weight of the total glass medium.

The glass solidified body may have a compressive strength of 100 MPa or more as a result of a waste solidified body compressive strength test.

The glass solidified body may have a compressive strength of 50 MPa or more as a result of a compressive strength test after irradiation ^{with 1.0 x 10 7 Gy radiation.}

The compressive strength after the ASTM B553 thermal cycle test may be 100 MPa or more.

preparing a glass medium powder comprising the present disclosure borosilicate glass and an inorganic adsorbent; preparing a mixture by mixing radioactive waste with the glass medium powder; melting the mixture to prepare a melt; and quenching the melt to obtain a solidified body.

In the step of preparing a melt by melting the mixture; in the melting temperature is 1400 ℃ or less, the melting time may be 1 to 60 minutes.

In the step of preparing a glass medium powder comprising borosilicate glass and an inorganic adsorbent, the mixing ratio of the borosilicate glass and the inorganic adsorbent may be 1:9 to 5:5 by weight.

Preparing a mixture by mixing the radioactive waste with the mixed powder; In, the radioactive waste may be included in an amount of 0.1 to 0.5% by weight based on 100% by weight of the glass medium powder.

According to the present disclosure, it is possible to provide a glass solidified body obtained by stably vitrifying Cancrinite, which is an inorganic adsorbent for adsorbing radioactive waste, and a method for manufacturing the same.

According to the present disclosure, it is possible to provide a glass solidified body including an inorganic material adsorbent that effectively adsorbs radioactive waste in terms of volume reduction and a method for manufacturing the same.

According to the present disclosure, it is possible to provide a glass solidified body that satisfies the leaching regulation standards and compressive strength standards while containing an appropriate amount of radioactive waste, and a method for manufacturing the same.

1 shows a glass solidified body sample prepared by cutting the solidified body prepared in one embodiment of the present disclosure to a size of 0.8 x 0.8 cm and polishing the surface.

Terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and/or sections. These terms are used only to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

The terminology used herein is for the purpose of referring to specific embodiments only, and is not intended to limit the invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and includes the presence or absence of another characteristic, region, integer, step, operation, element and/or component. It does not exclude additions.

When a part is referred to as being “on” or “on” another part, it may be directly on or on the other part, or the other part may be involved in between. In contrast, when a part refers to being "directly above" another part, the other part is not interposed therebetween.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Commonly used terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related art literature and the presently disclosed content, and unless defined, are not interpreted in an ideal or very formal meaning.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

The present disclosure discloses borosilicate glass for low temperature melting (borosilicate glass, borosilicate glass, We want to develop a glass solidified body containing borosilicate glass).

The present disclosure discloses a glass solidified body comprising borosilicate glass and an inorganic adsorbent containing medium and low level radioactive waste, and their mixing ratio and mixing step, a step of preparing a melt after mixing, and a method for finally preparing a glass solidified body by solidifying it And to provide a glass solidified body prepared therefrom.

The glass solidified body of one embodiment of the present disclosure includes a glass medium including borosilicate glass (borosilicate glass) and an inorganic adsorbent, and radioactive waste, and the borosilicate glass is SiO ₂ , B ₂ O ₃ , Li ₂ O, CaO may be included.

The glass medium may include borosilicate glass and inorganic adsorbent in a weight ratio of borosilicate glass:inorganic adsorbent in a weight ratio of 3:7 to 5:5. Specifically, the weight ratio may be 5:5 to 4:6, more specifically 3:7. If the mixing ratio of the borosilicate glass is too low or the mixing ratio of the inorganic adsorbent is too high, the ratio of aluminum may become too high and the melting temperature may rise rapidly, and if the mixing ratio of the inorganic adsorbent is too low or the mixing ratio of the borosilicate glass is too high, the chemical durability may decrease. can

The borosilicate glass is based on 100% by weight of the total borosilicate glass, SiO ₂ : 30 to 35% by weight, B ₂ O ₃ : 50 to 60% by weight, Li ₂ O: 3 to 8% by weight, CaO: 3 to 8% by weight , may include Specifically, the borosilicate glass is based on 100% by weight of the total borosilicate glass, SiO ₂ : 32 to 34% by weight, B ₂ O ₃ : 55 to 58% by weight, Li ₂ O: 4 to 6% by weight, CaO: 4 to 6 % by weight, may include.

The inorganic adsorbent may be a zeolite.

The inorganic adsorbent may be Cancrinite.

The chemical formula of the inorganic adsorbent may be Na ₈ [AlSiO ₄ ] _{6CO 3} ·3.4H ₂ O. The ratio of Si: Al: Na of the inorganic adsorbent is 6: 6: 8 (mol ratio).

_{The inorganic adsorbent may include SiO 2} : 35 to 45 wt%, Al ₂ O ₃ : 28 to 38 wt%, Na ₂ O: 22 to 32 wt%, based on 100 wt% of the total inorganic adsorbent. _{Specifically, the inorganic adsorbent may include SiO 2} : 38 to 42 wt%, Al ₂ O ₃ : 31 to 34 wt%, Na ₂ O: 25 to 29 wt%, based on 100 wt% of the total inorganic adsorbent.

The radioactive waste is medium and low-level radioactive waste, at least one oxide selected from the group consisting of iron (Fe), chromium (Cr), cesium (Cs), nickel (Ni), cobalt (Co) and manganese (Mn). can

The radioactive waste may be included in an amount of 0.1 to 0.5% by weight based on 100% by weight of the total glass medium. More specifically, the radioactive waste may be included in an amount of 0.2 to 0.4% by weight based on 100% by weight of the total glass medium.

The glass solidified body may have a compressive strength of 100 MPa or more as a result of a waste solidified body compressive strength test. Specifically, the glass solidified body may have a compressive strength of 100 to 150 MPa, more specifically 140 to 150 MPa, as a result of a waste solidified compressive strength test.

The glass solidified body may have a compressive strength of 50 MPa or more as a result of a compressive strength test after irradiation ^{with 1.0 x 10 7 Gy radiation.} Specifically, the glass solidified body may have a compressive strength of 50 to 100 MPa, more specifically 70 to 80 MPa, as a result of a compressive strength test after irradiation ^{with 1.0 x 10 7 Gy radiation.}

The glass solidified body may have a compressive strength of 100 MPa or more after the ASTM B553 thermal cycle test. Specifically, the glass solidified body may have a compressive strength of 100 to 150 MPa, more specifically 110 to 130 MPa after the ASTM B553 thermal cycle test.

The manufacturing method of the glass solidified body of one embodiment of the present disclosure comprises the steps of preparing a glass medium powder comprising borosilicate glass and an inorganic adsorbent; preparing a mixture by mixing radioactive waste with the glass medium powder; melting the mixture to prepare a melt; and quenching the melt to obtain a solidified body.

In the step of preparing a melt by melting the mixture; in the melting temperature is 1400 ℃ or less, the melting time may be 1 to 60 minutes. Specifically, the melting temperature may be 1300 to 1400 ℃, more specifically 1350 to 1400 ℃. Specifically, the melting time may be 20 to 60 minutes, more specifically 30 to 50 minutes. If the melting temperature exceeds 1400 degrees, it may be difficult to apply to a large electric furnace.

In the step of preparing a glass medium powder comprising borosilicate glass and an inorganic adsorbent, the mixing ratio of the borosilicate glass and the inorganic adsorbent may be 1:9 to 5:5 by weight. Specifically, the mixing ratio of the borosilicate glass and the inorganic adsorbent may be 2:8 to 4:6 by weight, and more specifically 3:7.

Preparing a mixture by mixing the radioactive waste with the mixed powder; In, the radioactive waste may be included in an amount of 0.1 to 0.5% by weight based on 100% by weight of the glass medium powder. More specifically, the radioactive waste may be included in an amount of 0.2 to 0.4% by weight based on 100% by weight of the total glass medium.

In the step of preparing the glass medium powder including the borosilicate glass and the inorganic adsorbent, the composition and type of the borosilicate glass and the inorganic adsorbent are as described above.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only, and the present invention is not limited thereto.

Example

Borosilicate glass is composed of SiO ₂ , B ₂ O ₃ , Li ₂ O, and CaO. Considering the melting point (<1400 ^o C) and high chemical durability, the composition of borosilicate glass is shown in Table 1.

division SiO ₂ B ₂ O ₃ Li ₂ O CaO content (wt%) 33.3 56.7 5 5

The chemical formula of the inorganic adsorbent (Cancrinite) is Na ₈ [AlSiO ₄ ] _{6CO 3} ·3.4H ₂ O, and the ratio of Si: Al: Na is 6: 6: 8 (mol ratio). The composition of Cancrinite used in the invention is shown.

division SiO ₂ Al ₂ O ₃ Na ₂ O content (wt%) 40 32.9 27.1

A glass medium was formed by mixing the borosilicate glass having the composition of Table 1 and the inorganic adsorbent having the composition of Table 2. The mixing ratio was mixed at a weight ratio of borosilicate glass:inorganic adsorbent = 3:7.

The composition of the glass medium mixed at the mixing ratio is shown in Table 3.

division SiO ₂ B ₂ O ₃ Li ₂ O CaO Al ₂ O ₃ Na ₂ O (3:7 mixed)% by weight 38 17 1.5 1.5 23 19

In addition, the medium and low level waste contained in the glass medium is iron (Iron, Fe), chromium (Chromium, Cr), cesium (Cesium, Cs), nickel (Nickel, Ni), cobalt (Cobalt, Co) and manganese ( Manganese, Mn) oxide and 0.21 mol% of waste was added in the solidified body. The composition expressed in wt% with respect to 100 wt% of the total glass medium is shown in Table 4. Based on 100% by weight of the total glass medium, medium and low level waste was included in an amount of 0.303% by weight.

division Fe ₂ O ₃ Cr ₂ O ₃ Cs ₂ O NiO CoO MnO weight% 0.1 0.036 0.004 0.06 0.003 0.1

The glass medium of the composition of Table 3 and the solidified body of the final composition including the radioactive waste of the composition of Table 4 were mixed and ^{melted at 1350 o} C for 40 minutes to prepare a melt. After melting, it was rapidly cooled at room temperature to prepare a final solidified body. 1 shows a solid sample prepared by cutting the prepared solid body into a size of about 0.8 x 0.8 cm and polishing the surface.

Table 5 corresponds to the results after performing a PCT (Product Consistency Test) test to evaluate the chemical durability of glass, and it can be seen that it is lower than ^{the leaching regulation standard of 2g/m 2 for all elements.} Therefore, it turns out that the chemical durability of the glass solidified body of this invention is high by this.

Si Al Na B Ca Li Fe Cr Cs Ni Co Mn [g/m ² ] 0.156 0.214 0.492 0.606 0.005 0.219 0.047 0.073 0.0002 0.007 0.014 0.013

In addition, a total of three types of disposal suitability were evaluated to satisfy the criteria for receiving radioactive waste from domestic repositories. (Standard: (1) Compressive strength of solid waste: 3.44 MPa or more, (2) ^{Compressive strength after 1.0 x 10 7} Gy irradiation: 3.44 MPa or more, (3) ASTM B553 Compressive strength after thermal cycle test: 3.44 MPa or more) As a result, it was found that (1) 146.7 MPa, (2) 73.2 MPa, and (3) 118.7 MPa satisfies the conditions for receiving radioactive waste from a domestic repository.

The present invention is not limited to the embodiments, but may be manufactured in various different forms, and those of ordinary skill in the art to which the present invention pertains can use other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that this may be practiced. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (15)

a glass medium comprising borosilicate glass and an inorganic adsorbent, and
containing radioactive waste;
The borosilicate glass comprises SiO ₂ , B ₂ O ₃ , Li ₂ O, CaO, a glass solidified body. According to claim 1,
The glass medium comprises borosilicate glass and an inorganic adsorbent.
Borosilicate glass: a glass solidified body comprising 1:9 to 5:5 by weight of the inorganic adsorbent. According to claim 1,
The borosilicate glass is based on 100% by weight of the total borosilicate glass,
SiO ₂ : 30 to 35 wt%
B ₂ O ₃ : 50 to 60 wt%
Li ₂ O: 3 to 8 wt%
CaO: 3 to 8% by weight
Containing, a glass solidified body. According to claim 1,
The inorganic adsorbent is a zeolite, a glass solidified body. 5. The method of claim 4,
The inorganic adsorbent is Cancrinite, a glass solidified body. According to claim 1,
The inorganic adsorbent is based on 100% by weight of the total inorganic adsorbent.
SiO ₂ : 35 to 45 wt%
Al ₂ O ₃ : 28 to 38 wt%
Na ₂ O: 22 to 32 wt%
Containing, a glass solidified body. According to claim 1,
The radioactive waste is low- and medium-level radioactive waste,
A glass solidified material, which is at least one oxide selected from the group consisting of iron (Fe), chromium (Cr), cesium (Cs), nickel (Ni), cobalt (Co) and manganese (Mn). According to claim 1,
The radioactive waste is contained in an amount of 0.1 to 0.5% by weight based on 100% by weight of the total glass medium, a glass solidified body. According to claim 1,
The glass solidified body has a compressive strength of 100 MPa or more as a result of the waste solidified body compressive strength test. According to claim 1,
The glass solidified body has a compressive strength of 50 MPa or more as a result of a compressive strength test after irradiation ^{with 1.0 x 10 7 Gy radiation, a glass solidified body.} According to claim 1,
A glass solidified body having a compressive strength of at least 100 MPa after the ASTM B553 thermal cycle test. preparing a glass medium powder comprising borosilicate glass and an inorganic adsorbent;
preparing a mixture by mixing radioactive waste with the glass medium powder;
melting the mixture to prepare a melt; and
A method of producing a glass solidified body, including; obtaining a solidified body by quenching the melt. 13. The method of claim 12,
In the step of melting the mixture to prepare a melt;
The melting temperature is 1400° C. or less and the melting time is 1 to 60 minutes, a method for producing a glass solidified body. 13. The method of claim 12,
Preparing a glass medium powder comprising borosilicate glass and an inorganic adsorbent; in
The mixing ratio of borosilicate glass and inorganic adsorbent is 1:9 to 5:5 by weight, a method for producing a glass solidified body. 13. The method of claim 12,
Preparing a mixture by mixing the radioactive waste with the mixed powder; In,
Radioactive waste is contained in an amount of 0.1 to 0.5% by weight based on 100% by weight of the glass medium powder, a method for producing a glass solidified body.

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