A method for enhancing the reaction between high-level radioactive waste and glass substrate during glass solidification

Abstract

The present invention proposes a method for enhancing the reaction between high-level radioactive waste and a glass substrate during the vitrification process, comprising the following steps: S1. uniformly mixing base glass powder, borax, and water, and granulating to obtain a sample pellet precursor; S2. drying and heat-treating the sample pellet precursor to obtain a composite glass substrate pellet; S3. uniformly mixing the composite glass substrate pellet with high-level radioactive waste, melting it, and cooling it to obtain a glass solidification body. The present invention belongs to the field of new materials industry. Using composite glass substrate pellets to solidify high-level radioactive waste can reduce the temperature for the complete decomposition of nitrates in the waste by approximately 150°C. In addition, the borax adhesive decomposes into Na and B at high temperatures, which can serve as essential elements for glass formation and avoid the introduction of foreign impurities. The method provided by the present invention can significantly increase the reaction rate between the glass substrate and high-level radioactive waste, achieving efficient conversion of high-level radioactive waste to a glassy state during the vitrification process, thereby reducing overall processing costs and energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of new materials industry, and in particular to a method for enhancing the reaction between high-level radioactive waste and a glass substrate during a glass solidification process. Background Art

[0002] As an efficient and clean energy source, nuclear energy boasts high energy density, stable power generation, and low long-term operating costs, making it a crucial pillar for my country to achieve its "dual carbon" goals. To ensure the sustainable development of nuclear energy, my country has developed a closed nuclear fuel cycle. However, this closed nuclear fuel cycle inevitably produces high-level radioactive waste (HLW). HLW has a complex composition, typically containing more than 20 components, and is highly biotoxic and radioactive.

[0003] Immobilizing nuclear waste in a stable matrix (also known as a solidified structure) to prevent the migration of radionuclides, followed by deep geological disposal, is currently the most widely accepted approach internationally. Immobilization of high-level radioactive waste is a crucial step in nuclear waste disposal. Its primary goal is to seal radioactive materials in a stable matrix through appropriate solidification methods, thereby preventing harm to the environment and humans. Glass materials have a wide tolerance for different fission products, and the glass production process is simple and amenable to remote control. Therefore, vitrification technology is currently the only industrially applicable and most mature method for the disposal of high-level radioactive waste.

[0004] The most widely used vitrification process, using Joule-heated ceramic electric furnaces, involves feeding a glass substrate and high-level radioactive waste into the furnace at a specific ratio and rate. Through a series of overlapping and mutually influencing physical and chemical reactions and phase transitions, a stable glass solid is formed. During the vitrification process, the high-level radioactive waste is fed into the furnace as a liquid, while the glass substrate is fed as a solid. To ensure smooth and stable transport of the glass substrate through the equipment pipelines, the glass substrate must be processed into 1-3 mm glass beads. However, due to their small specific surface area and low reactivity, the waste-glass substrate reacts slowly and cannot effectively encapsulate larger ions or ion clusters in the waste.

[0005] Therefore, if the interaction between basic glass and high-level radioactive waste during high-temperature processes can be enhanced, the reaction activity between the two can be increased, and the efficient conversion of waste into glassy state can be improved. Summary of the Invention

[0006] In view of this, the present invention proposes a method for enhancing the reaction between high-level radioactive waste and a glass substrate during the glass solidification process to solve the problem that the existing glass substrate has low reactivity, its reaction rate with high-level radioactive waste with complex components is slow during the high-temperature melting process, and the waste has a low conversion rate to a glassy state, resulting in the base glass being unable to efficiently solidify harmful substances in the waste.

[0007] The technical solution of the present invention is achieved as follows:

[0008] In a first aspect, the present invention provides a method for enhancing the reaction between high-level radioactive waste and a glass substrate during a vitrification process, comprising the following steps:

[0009] S1. Mixing basic glass powder, borax and water, and granulating to obtain sample pellet precursors;

[0010] S2, drying and heat-treating the sample pellet precursor to obtain composite glass substrate pellets;

[0011] S3. Evenly mix the composite glass substrate pellets with high-level radioactive waste, melt them, and cool them to obtain a glass solidified body.

[0012] This method first grinds the glass substrate into a micron-sized base glass powder. A certain amount of borax and water are then added to the base glass powder, followed by pelletization, drying, and heat treatment to produce composite glass substrate pellets. The composite glass substrate pellets can be sized from 1 to 3 mm, as needed, to meet the glass substrate feed requirements. Once the composite glass substrate pellets enter the furnace, as the temperature rises, the millimeter-sized sample gradually loosens and transforms into micron-sized glass powder. This increases its specific surface area and reactivity, accelerating the physicochemical reaction between the base glass and high-level radioactive waste, increasing the conversion rate of high-level radioactive waste to a glassy state, and thus improving the efficiency of the glass substrate in solidifying the high-level radioactive waste.

[0013] Compared with the reaction between glass beads and high-level radioactive waste, the composite glass substrate beads prepared by the present invention can react with high-level radioactive waste to achieve glass powderization during the reaction process while ensuring smooth feeding of basic glass, thereby enhancing the reactivity of basic glass and high-level radioactive waste components and more efficiently solidifying the waste components in the glass matrix.

[0014] On the basis of the above technical solution, further, the particle size of the basic glass powder is 0.045~0.300mm.

[0015] The particle size range of the basic glass powder is 0.045~0.300 mm. The lower limit of 0.045 mm avoids excessive foaming during the glass solidification process caused by too small particle size and is susceptible to airflow disturbance in the open operation link, resulting in reduced raw material utilization during the granulation process. The upper limit of 0.300 mm avoids excessive particle size, which makes the preparation of composite glass substrate beads difficult and the spherical surface rough, affecting smooth feeding in the pipeline.

[0016] On the basis of the above technical solution, further, calculated by mass percentage, the content of the basic glass powder is 65-70 wt%, the content of borax is 3-5 wt%, and the content of water is 27-30 wt%.

[0017] If the amount of borax added is less than 3 wt%, the adhesive content is too low and the bonding is not strong enough to form balls; if the amount of borax added is higher than 5 wt%, the adhesive content is higher than 5 wt%, resulting in a significant decrease in fluidity, affecting granulation and other processes and preventing ball formation;

[0018] If the amount of water added is less than 27 wt%, the water content of the slurry is too low, the three cannot be connected together by water, and cannot form balls; if the amount of water added is higher than 30 wt%, the water content of the slurry is too high, the fluidity is too high, and cannot form balls.

[0019] On the basis of the above technical solution, further, the drying temperature is 55-95°C.

[0020] The mass change of the sample pellet precursor can be obtained by weighing the sample pellet precursor every 1 hour. It has been verified that when the water-containing sample pellet precursor is placed in an oven at 55~95℃ for a certain period of time, the mass change is <0.5 wt%, and it is considered to be dry, thus obtaining a dry sample pellet precursor.

[0021] On the basis of the above technical solution, further, the heat treatment is to raise the temperature of the dried sample pellet precursor to 300-350° C. and keep the temperature for 2-10 h.

[0022] The bonding temperature range of the borax (Na2B4O7·10H2O) is 250-380° C., preferably 300-350° C. Below this range, the anhydrous borax is not activated, while above this range, the bonding phase stability decreases.

[0023] The borax (Na2B4O7·10H2O) melts at 75°C and can be dehydrated to solid anhydrous borax (Na2B4O7) within 200°C. The anhydrous borax can be effectively bonded to the basic glass powder at 300-350°C. When the temperature exceeds 400°C, the anhydrous borax will volatilize and decompose, and the bonding effect will fail.

[0024] When the temperature is 400~700℃, anhydrous borax (Na2B4O7) begins to decompose to produce sodium metaborate (NaBO2) and boron trioxide (B2O3); when the temperature is higher than 800℃, sodium metaborate (NaBO2) may further decompose into sodium oxide (Na2O) and (B2O3).

[0025] On the basis of the above technical solution, further, in step S3, the content of the composite glass substrate beads is 75-90 wt%, and the content of the high-level radioactive waste is 10-25 wt%, calculated by mass percentage.

[0026] On the basis of the above technical solution, further, the particle size of the composite glass substrate beads is 1-3 mm.

[0027] On the basis of the above technical solution, further, the composition of the basic glass powder, calculated as oxides, includes multiple types of SiO2, B2O3, Na2O, CaO, Al2O3, Li2O, ZnO and V2O5.

[0028] On the basis of the above technical solution, further, the chemical composition of the high-level radioactive waste, calculated as oxides, includes multiple types of MoO3, ZrO2, La2O3, Nd2O3, Ce2O3, Y2O3, Sm2O3, Gd2O3, Fe2O3, Cr2O3, NiO, MnO, TiO2, TeO2, Ag2O, CdO, CaO, SrO, BaO, Na2O, K2O, Cs2O, Rb2O and Al2O3.

[0029] On the basis of the above technical solution, further, the melting in step S3 is performed at 1050-1250° C. for 1-24 h.

[0030] On the basis of the above technical solution, further, the basic glass powder in step S1 is obtained by melting basic glass raw materials with a given chemical composition at 1100-1300° C. for 1-24 hours and then grinding them.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The method provided by the present invention for enhancing the reaction between high-level radioactive waste and glass substrate during the glass solidification process can significantly increase the conversion rate of high-level radioactive waste to a glassy state. By pre-grinding the glass substrate into a micron-sized powder and granulating it into a granulated shape, the composite glass substrate beads are rapidly loosened into original micron-sized particles under the high-temperature environment of the melting furnace. The specific surface area of the particles is increased by 2 to 3 orders of magnitude compared to traditional 1 to 3 mm solid glass beads. The contact area between the micron-sized glass powder and the high-level radioactive waste is greatly increased, the reaction activity is significantly enhanced, the efficient reaction reduces the residual uncoated waste liquid, and the encapsulation performance of the solidified body for harmful elements is significantly improved. At the same time, the melting time can be effectively shortened, thereby achieving efficient conversion of high-level radioactive waste to a glassy state during the glass solidification process. At the same time, the overall processing cost and energy consumption can be reduced.

[0033] (2) The use of composite glass-based beads can reduce the decomposition temperature of nitrate in high-level radioactive waste by about 150°C by enhancing the contact efficiency of the reaction interface, thereby reducing the impact of nitrate on the solidification of harmful substances during the high-level radioactive waste glass solidification process.

[0034] (3) The size of the composite glass substrate beads (1-3 mm) is consistent with that of traditional glass beads, eliminating the need to modify the pipeline transportation system and furnace structure. Furthermore, the borax adhesive decomposes into Na and B at high temperatures, which can serve as essential elements for glass formation, avoiding the introduction of foreign impurities. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a graph showing the conversion rate of the composite glass substrate pellets and waste powder in Example 1 at a heating rate of 10°C / min;

[0037] Figure 2 This is a graph showing the conversion rate of the composite glass substrate pellets and waste powder in Example 2 at a heating rate of 10°C / min;

[0038] Figure 3 This is a graph showing the conversion rate of the composite glass substrate pellets and waste powder at a heating rate of 10°C / min in Example 3;

[0039] Figure 4 This is a graph showing the conversion rate of the composite glass substrate pellets and waste powder at a heating rate of 10°C / min in Example 4;

[0040] Figure 5 This is a graph showing the conversion rate of the composite glass substrate pellets and waste powder at a heating rate of 10°C / min in Example 5;

[0041] Figure 6 This is a conversion curve of glass beads and waste powder in Comparative Example 1 at a heating rate of 10°C / min. DETAILED DESCRIPTION

[0042] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In the following specific embodiments, a comprehensive thermal analyzer (TG-DSC) was used to record the heat absorption and release behavior and mass loss changes of the composite glass substrate pellets / glass beads and waste powder in the examples and comparative examples during the heating process at a heating rate of 10°C / min;

[0044] Substituting the thermogravimetric data obtained from the comprehensive thermal analysis test into the following formula, the conversion rate curve of the composite glass substrate pellets and waste powder during the heating process was obtained:

[0045]

[0046] Among them, α （T） represents the conversion rate of the composite glass-based pellets and waste powder during the heating process; m(T) represents the mass of the composite glass-based pellets and waste powder at temperature T, m0 represents the initial mass of the composite glass-based pellets and waste powder; m1 represents the stable mass of the composite glass-based pellets and waste powder after decomposition;

[0047] Conversion rate α (T) :This parameter is used to characterize the thermal decomposition process of nitrate components during the formation of glass solidification bodies when high-level radioactive waste is solidified using glass substrates. It is defined as the normalized ratio of the actual decomposition amount of nitrate in the system to the theoretical complete decomposition amount (definition domain: α (T) ∈[0,1]). When α (T) →0, it indicates that the nitrate has not yet decomposed; when α (T) →1, it means that the nitrate is close to complete decomposition, and its residual phase concentration is close to the analytical detection limit. The lower the temperature corresponding to the conversion rate approaching 1, the faster the overall reaction rate of the system and the higher the curing efficiency.

[0048] In the following specific embodiments, the oxide components obtained by adding borax, water and basic glass powder to melt in the examples are the same as the glass beads in Comparative Example 1 and the oxide components obtained by adding borax, water and basic glass powder to melt in Comparative Examples 2-6.

[0049] Example 1

[0050] This embodiment provides a method for enhancing the reaction between high-level radioactive waste and a glass substrate during a vitrification process. The designed composition of the borosilicate base glass is shown in Table 1, and the composition of the simulated high-level radioactive waste is shown in Table 2. The method includes the following steps:

[0051] (1) Weigh 150 g of borosilicate basic glass raw materials (SiO2, B2O3, Al2O3 introduced as oxides, CaO, Na2O, Li2O introduced as carbonates), mix them evenly, place them in a corundum crucible, melt them at 1150°C for 1 h, cool them to room temperature, crush them, and grind them to obtain basic glass powder. The particle size of the basic glass powder is 0.100 mm.

[0052] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 70:3:27 to form granules, which were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 75 °C for 2 h, heated from room temperature to 325 °C in an annealing furnace at a heating rate of 5 °C / min and kept at that temperature for 5 h. The pellets were then cooled in the furnace to obtain finished composite glass substrate pellets.

[0053] (3) According to the ratio of 82 wt% composite glass substrate pellets and 18 wt% calcined simulated high-level waste powder (calculated as oxide), a total of 150 g was weighed and mixed evenly. The mixture was melted at 1050 °C for 1 h, cast on a steel plate and air-cooled to obtain a glass solid.

[0054] A sample with a total mass of approximately 10 mg was weighed, and its ratio was 82 wt% of composite glass substrate pellets and 18 wt% of calcined simulated high-level waste powder (calculated as oxide).

[0055] A comprehensive thermal analyzer was used to record the endothermic and exothermic behaviors and mass loss changes during the heating process at a heating rate of 10 °C / min.

[0056] Substituting the thermogravimetric data obtained from the comprehensive thermal analysis test into the following formula, the conversion rate curve of the composite glass substrate pellets and waste powder during the heating process was obtained:

[0057]

[0058] α (T) Indicates the conversion rate of composite glass substrate pellets and waste powder during heating; m (T) represents the mass of the composite glass substrate pellets and waste powder at temperature T, m0 represents the initial mass of the composite glass substrate pellets and waste powder; m1 represents the stable mass of the composite glass substrate pellets and waste powder after decomposition.

[0059] Figure 1 The conversion rate curve of the composite glass substrate pellets and waste powder in Example 1 at a heating rate of 10°C / min can be seen from the figure. When the temperature reaches 580°C, the conversion rate is approximately 1, indicating that the nitrate is close to complete decomposition at this time.

[0060] Table 1 Design composition of borosilicate base glass in Example 1 (wt%)

[0061]

[0062] Table 2 Composition of high-level radioactive waste in Example 1 (wt%)

[0063]

[0064] Example 2

[0065] This embodiment provides a method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification. The difference from embodiment 1 is that:

[0066] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 70:3:27 to form granules, which were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 75 °C for 2 h, heated from room temperature to 350 °C in an annealing furnace at a heating rate of 5 °C / min and kept at this temperature for 2 h. The pellets were then cooled in the furnace to obtain finished composite glass substrate pellets.

[0067] The comprehensive thermal analysis experimental test was carried out according to the steps of Example 1.

[0068] Figure 2 The conversion rate curve of the composite glass substrate pellets and waste powder in Example 2 at a heating rate of 10°C / min can be seen from the figure. When the temperature reaches 600°C, the conversion rate is approximately 1, indicating that the nitrate is close to complete decomposition at this time.

[0069] Example 3

[0070] This embodiment provides a method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification. The difference from embodiment 1 is that:

[0071] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 70:3:27 to form granules, which were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 75 °C for 2 h, heated from room temperature to 300 °C in an annealing furnace at a heating rate of 5 °C / min and kept at this temperature for 10 h. The pellets were then cooled in the furnace to obtain finished composite glass substrate pellets.

[0072] The comprehensive thermal analysis experimental test was carried out according to the steps of Example 1.

[0073] Figure 3 The conversion rate curve of the composite glass substrate pellets and waste powder in Example 3 at a heating rate of 10°C / min can be seen from the figure. When the temperature reaches 660°C, the conversion rate is approximately 1, indicating that the nitrate is close to complete decomposition at this time.

[0074] Example 4

[0075] This embodiment provides a method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification. The difference from embodiment 1 is that:

[0076] The designed composition of borosilicate base glass is shown in Table 3.

[0077] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 65:5:30 to form granules. The granules were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 95°C for 1 h, heated from room temperature to 325°C in an annealing furnace at a heating rate of 5°C / min and kept at that temperature for 5 h. The pellets were cooled in the furnace to obtain finished composite glass substrate pellets. The particle size of the base glass powder was 0.045 mm.

[0078] (3) According to the ratio of 82 wt% composite glass substrate pellets and 18 wt% calcined simulated high-level waste powder (calculated as oxide), a total of 150 g was weighed and mixed evenly. The mixture was melted at 1150 °C for 10 h, cast on a steel plate and cooled to obtain a glass solid.

[0079] The comprehensive thermal analysis experimental test was carried out according to the steps of Example 1.

[0080] Figure 4 The conversion rate curve of the composite glass substrate pellets and waste powder in Example 4 at a heating rate of 10°C / min can be seen from the figure. When the temperature reaches 660°C, the conversion rate is approximately 1, indicating that the nitrate is close to complete decomposition at this time.

[0081] Table 3 Design composition of borosilicate base glass of Example 4 (wt%)

[0082]

[0083] Example 5

[0084] This embodiment provides a method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification. The difference from embodiment 1 is that:

[0085] The designed composition of borosilicate base glass is shown in Table 4.

[0086] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 67.5:4:28.5 to form granules. The granules were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 55 °C for 3 h, heated from room temperature to 325 °C in an annealing furnace at a heating rate of 5 °C / min and kept at that temperature for 5 h. The pellets were cooled in the furnace to obtain finished composite glass substrate pellets. The particle size of the base glass powder was 0.300 mm.

[0087] (3) According to the ratio of 82 wt% composite glass substrate pellets and 18 wt% calcined simulated high-level radioactive waste powder (calculated as oxide), a total of 150 g was weighed and mixed evenly, melted at 1250 °C for 24 h, cast on a steel plate and cooled to obtain a glass solid.

[0088] The comprehensive thermal analysis experimental test was carried out according to the steps of Example 1.

[0089] Figure 5 The conversion rate curve of the composite glass substrate pellets and waste powder in Example 5 at a heating rate of 10°C / min can be seen from the figure. When the temperature reaches 620°C, the conversion rate is approximately 1, indicating that the nitrate is close to complete decomposition at this time.

[0090] Table 4 Design composition of borosilicate base glass in Example 5 (wt%)

[0091]

[0092] Comparative Example 1

[0093] This comparative example differs from Example 1 in that the design composition of the borosilicate base glass is as shown in Table 5. Experiments were conducted using glass beads and high-level radioactive waste. The experimental process is as follows:

[0094] (1) Glass beads with a particle size of 1-3 mm are prepared using the existing fire-polishing method;

[0095] (2) 82 wt% glass beads and 18 wt% calcined simulated high-level waste powder (calculated as oxide) were weighed in a total of 150 g and mixed evenly. The mixture was placed in a corundum crucible and melted at 1050 °C for 1 h. The mixture was cast on a steel plate and air-cooled to obtain a glass solid.

[0096] A comprehensive thermal analysis experiment was conducted using glass beads and high-level radioactive waste powder according to the steps of Example 1.

[0097] Figure 6 The figure shows the conversion rate of glass beads and waste powder at a heating rate of 10°C / min in Comparative Example 1. It can be seen from the figure that when the temperature reaches 740°C, the conversion rate is approximately 1, indicating that the nitrate is nearly completely decomposed at this time.

[0098] Table 5 Design composition of borosilicate base glass of Comparative Example 1 (wt%)

[0099]

[0100] Comparative Example 2

[0101] This comparative example differs from Example 1 in that step (2) is different:

[0102] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 70:3:27 to form granules, which were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 75 °C for 2 h, heated from room temperature to 200 °C in an annealing furnace at a heating rate of 5 °C / min and kept at this temperature for 5 h. The pellets were then cooled in the furnace to obtain finished composite glass substrate pellets.

[0103] The composite glass substrate pellets prepared in step (2) cannot provide liquid phase bonding because the anhydrous borax has not reached the melting temperature at this time, and cannot play the role of an adhesive. As a result, the composite glass substrate pellets have low strength and are easily broken into powder. Experiments with waste powder cannot be carried out in the form of pellets.

[0104] Comparative Example 3

[0105] This comparative example differs from Example 1 in that step (2) is different:

[0106] (2) The base glass powder, borax (Na2B4O7·10H2O) and water were mixed in a mass ratio of 70:3:27 to form granules. The granules were sieved to obtain sample pellet precursors with a size of 1-3 mm. The pellets were dried at 75 °C for 2 h, heated from room temperature to 400 °C in an annealing furnace at a heating rate of 5 °C / min and kept at that temperature for 5 h. The pellets were then cooled in the furnace to obtain finished composite glass substrate pellets.

[0107] The composite glass substrate pellets prepared in step (2) are vulnerable to volatilization and decomposition of anhydrous borax due to excessive heating, which in turn destroys the bonding stability. This results in the composite glass substrate pellets having low strength and being easily broken into powder. Therefore, the pellets cannot be used for experiments with waste powder.

[0108] Comparative Example 4

[0109] This comparative example is different from Example 1 in that:

[0110] The designed composition of the borosilicate base glass is shown in Table 6;

[0111] In step (2), the mass ratio of basic glass powder, borax (Na2B4O7·10H2O) and water is 70:2:28.

[0112] Table 6 Design composition of borosilicate base glass of Comparative Example 4 (wt%)

[0113]

[0114] The composite glass substrate pellets prepared in step (2) have poor bonding properties due to the small amount of borax added, and are easily broken into powder. Therefore, it is impossible to conduct experiments with the pellets and waste powder.

[0115] Comparative Example 5

[0116] This comparative example is different from Example 1 in that:

[0117] The designed composition of the borosilicate base glass is shown in Table 7;

[0118] In step (2), the mass ratio of basic glass powder, borax (Na2B4O7·10H2O) and water is 69:6:25.

[0119] Table 7 Design composition of borosilicate base glass of Comparative Example 5 (wt%)

[0120]

[0121] In step (2), due to the low water content of the slurry, the basic glass powder and borax cannot be wetted, the connection degree is low, and the ball cannot be formed, so subsequent experiments cannot be carried out.

[0122] Comparative Example 6

[0123] This comparative example is different from Example 1 in that:

[0124] The design composition of the borosilicate base glass is shown in Table 8;

[0125] In step (2), the mass ratio of basic glass powder, borax (Na2B4O7·10H2O) and water is 60:6:34.

[0126] Table 8 Design composition of borosilicate base glass of Comparative Example 6 (wt%)

[0127]

[0128] In step (2), the slurry had too high a water content and too high a fluidity to form balls, making subsequent experiments impossible.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification, characterized in that: The following steps are involved: S1. Mixing basic glass powder, borax and water, and granulating to obtain sample pellet precursors; S2, drying and heat-treating the sample pellet precursor to obtain composite glass substrate pellets; S3, mixing the composite glass substrate pellets with high-level radioactive waste, melting them, and cooling them to obtain a glass solidified body; Calculated by mass percentage, the content of the basic glass powder is 65-70 wt%, the content of borax is 3-5 wt%, and the content of water is 27-30 wt%; The heat treatment is to heat the dried sample pellet precursor to 300-350° C. and keep the temperature for 2-10 hours.

2. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: The particle size of the basic glass powder is 0.045-0.300 mm.

3. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: In step S3, the content of the composite glass substrate beads is 75-90 wt % and the content of the high-level radioactive waste is 10-25 wt %, calculated by mass percentage.

4. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: The particle size of the composite glass substrate beads is 1-3 mm.

5. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: The drying temperature is between 55°C and 95°C.

6. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: The composition of the base glass powder, calculated as oxides, includes multiple ones of SiO2, B2O3, Na2O, CaO, Al2O3, Li2O, ZnO and V2O5.

7. The method for enhancing the reaction between high-level radioactive waste and glass substrate during vitrification according to claim 1, wherein: The melting in step S3 is performed at 1050-1250° C. for 1-24 hours.

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