Preparation method of super-uranium nuclide glass solidified body

Abstract

The invention relates to a preparation method of a super-uranium nuclide glass solidified body. The preparation method of the super-uranium nuclide glass solidified body comprises the following steps: 1) mixing granite powder and boron oxide powder, and calcining to obtain granite glass body powder; 2) uniformly mixing cerium oxide and neodymium oxide to obtain cerium-neodymium oxide; 3) mixing the cerium-neodymium oxide with the granite glass body powder to obtain a base material, adding a super-uranium nuclide, adding a mixed medium, uniformly mixing, and performing compression molding to obtain a molded body; and 4) calcining the molded body for 1-3 hours at the temperature of 1200-1400 DEG C in an inert atmosphere to obtain the ultra-uranium nuclide glass solidified body. According to the preparation method disclosed by the invention, the cerium-neodymium oxide is used for cooperating with the granite glass body powder to solidify the super-uranium nuclide under a relatively mild condition, so that the bonding problem of a crucible and a solidified body during solidification and sintering is solved, and the super-uranium nuclide glass solidified body with good chemical stability is obtained.

Description

Technical Field

[0001] The invention relates to a method for preparing a transuranium nuclide glass solidified body, belonging to the technical field of industrial treatment and application of nuclear waste. Background Art

[0002] High level waste (HLW) is one of the most difficult forms of nuclear waste to handle, and it mainly exists in the form of waste liquid (wastewater). Although the volume of HLW is less than 1% of the volume of nuclear waste generated by the nuclear fuel cycle, its radioactivity exceeds 99% of the total radioactivity of the nuclear fuel cycle. Due to the complex composition and high volatility of HLW, it puts forward more stringent requirements on the adaptability (multi-nuclide, multi-component), inclusiveness (high solid solubility) and stability (mechanical, thermal and irradiation stability, etc.) of its solidification matrix.

[0003] In response to high-level radioactive liquid waste, the international community has proposed the technical ideas of "Partitioning and Transmutation (P&T)" and "Partitioning and Conditioning (P&C)", which have become international research hotspots. P&T is to separate transuranic elements and long-lived fission products (such as Tc-99, etc.) from high-level radioactive liquid waste, and then transform them into short-lived or stable nuclides through transmutation. While P&C is to separate actinides and highly radioactive and high-heat-releasing elements such as Sr-90 and Cs-137 through separation methods under the conditions where transmutation is not yet available, so as to convert high-level radioactive liquid waste into low- and medium-level radioactive liquid waste with low toxicity, and to condition the separated highly radioactive elements separately to reduce the amount of waste that needs deep geological disposal.

[0004] Solidification is an important step in ensuring the safe use of nuclear energy. High-level radioactive waste contains highly radioactive nuclides, such as neptunium, plutonium, americium, and technetium. These nuclides are highly toxic and have long half-lives. Once leaked, they will have long-term effects on the environment and human health.

[0005] The effective treatment of high-level radioactive waste is the key to the sustainable development of nuclear energy. Through solidification treatment, the impact of nuclear waste on the environment can be reduced, the public's acceptance of nuclear energy utilization can be improved, and support can be provided for the long-term development of nuclear energy. Summary of the invention

[0006] Problem that the invention aims to solve

[0007] The purpose of the present invention is to solve the problem of solidification of transuranic nuclides after separation of high-level radioactive waste in the prior art, provide a method for preparing a transuranic nuclide glass solidification body, and provide a more feasible solidification method for permanent disposal of transuranic nuclide waste.

[0008] Solutions for solving problems

[0009] The present invention provides a method for preparing a transuranium nuclide glass solidified body, comprising the following steps:

[0010] 1) Mixing granite powder and boron oxide powder and calcining them to obtain granite glass powder;

[0011] 2) Evenly mixing cerium oxide and neodymium oxide to obtain cerium-neodymium oxide;

[0012] 3) Mixing the cerium-neodymium oxide and the granite glass powder as a base material, adding transuranic nuclides, adding a mixed medium, mixing evenly, and then pressing and molding to obtain a molded body;

[0013] 4) calcining the molded body at 1200° C.-1400° C. for 1-3 hours under an inert atmosphere to obtain a transuranic nuclide glass solidified body.

[0014] According to the preparation method of the present invention, in step 1), the mass ratio of the granite powder to the boron oxide powder is granite powder:boron oxide powder=(70-90):(10-30).

[0015] According to the preparation method of the present invention, in step 1), calcination is performed at 900-1100° C. for 1-3 hours, preferably at 1000° C. for 2 hours.

[0016] According to the preparation method of the present invention, in step 1), the particle size of the granite glass powder is below 200 meshes.

[0017] According to the preparation method of the present invention, in step 2), based on the total mass of cerium oxide and neodymium oxide, the content of cerium oxide is 30-70wt%, and the content of neodymium oxide is 30-70wt%.

[0018] According to the preparation method of the present invention, in step 3), based on the total mass of cerium-neodymium oxide and granite glass powder, the content of cerium-neodymium oxide is 10-30wt%, and the content of granite glass powder is 70-90wt%.

[0019] According to the preparation method of the present invention, in step 3), the transuranic nuclide is one or more of Am, Np and Pu.

[0020] According to the preparation method of the present invention, in step 3), the mixed medium is ethanol, and after being mixed evenly, the mixture is pressed at 8-10 MPa for 5-10 minutes to perform compression molding.

[0021] According to the preparation method of the present invention, in step 4), the temperature is raised to 1200°C-1400°C for calcination at a heating rate of 5-10°C / min, preferably raised to 1300°C at a heating rate of 5°C / min, and kept at this temperature for 2 hours.

[0022] According to the preparation method of the present invention, the total dose per 1g of the transuranium nuclide glass solidified body is 10 6 -10 7 Bq.

[0023] Effects of the Invention

[0024] The method for preparing a transuranic nuclide glass solidified body provided by the present invention is to solidify transuranic nuclide radioactive materials under relatively mild conditions by using cerium-neodymium oxide and granite glass powder, thereby solving the bonding problem between the crucible and the solidified body during solidification and sintering, obtaining a transuranic nuclide glass solidified body with good chemical stability, and laying a foundation for the research and development of solidification of transuranic nuclides separated from high-level waste liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 XRD diffraction test pattern of the transuranium nuclide glass solid body-I prepared in Example 1. DETAILED DESCRIPTION

[0026] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0027] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0028] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0029] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0030] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0031] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0032] In this specification, "room temperature" or "normal temperature" means "10-40°C".

[0033] The present invention provides a method for preparing a transuranium nuclide glass solidified body, comprising the following steps:

[0034] 1) Mixing granite powder and boron oxide powder and calcining them to obtain granite glass powder;

[0035] 2) Evenly mixing cerium oxide and neodymium oxide to obtain cerium-neodymium mixed oxide;

[0036] 3) Using the cerium-neodymium oxide as an inducing agent and the granite glass powder as a base material, adding transuranic nuclides, adding a mixed medium, mixing evenly, and then pressing and molding to obtain a molded body;

[0037] 4) calcining the molded body at 1200° C.-1400° C. for 1-3 hours under an inert atmosphere to obtain a transuranic nuclide glass solidified body.

[0038] The granite glass powder of the present invention has a wide tolerance for different elements and can realize the solidification of nuclides at the atomic scale. The obtained transuranium nuclide glass solidified body has excellent chemical stability and mechanical stability, can resist external impact and vibration, has good radiation resistance, and is suitable for the solidification of high-level radioactive waste.

[0039] Since Ce is tetravalent, similar to radioactive Np / Pu nuclides, and Nd is trivalent, similar to radioactive Am nuclides, CeO2 and Nd2O3 can be well contained in granite glass. According to the principle of isomorphous substitution, CeO2 and Nd2O3 are used to induce radioactive Np / Pu / Am nuclides to solidify in granite glass.

[0040] According to the preparation method of the present invention, in step 1), the mass ratio of the granite powder to the boron oxide powder is granite powder:boron oxide powder=(70-90):(10-30), preferably 80:20.

[0041] According to the preparation method of the present invention, in step 1), calcination is performed at 900-1100° C. for 1-3 hours, preferably at 1000° C. for 2 hours.

[0042] According to the preparation method of the present invention, in step 1), the particle size of the granite glass powder is below 200 meshes.

[0043] According to the preparation method of the present invention, in step 2), based on the total mass of cerium oxide and neodymium oxide, the content of cerium oxide is 30-70wt%, and the content of neodymium oxide is 30-70wt%. The use of cerium oxide and neodymium oxide in the above content range solves the solidification problem of transuranic nuclides with different contents.

[0044] According to the preparation method of the present invention, in step 3), based on the total mass of cerium-neodymium oxide and granite glass powder, the content of cerium-neodymium oxide is 10-30wt%, and the content of granite glass powder is 70-90wt%. This content range is conducive to the mixed materials forming a glass solid body.

[0045] According to the preparation method of the present invention, in step 3), the transuranic nuclide is one or more of Am, Np and Pu.

[0046] According to the preparation method of the present invention, in step 3), the mixed medium is ethanol, and after mixing evenly, the mixture is pressed at 8-10 MPa for 5-10 minutes, preferably at 8 MPa for 10 minutes.

[0047] According to the preparation method of the present invention, in step 4), the temperature is raised to 1200°C-1400°C for calcination at a heating rate of 5-10°C / min, preferably at a heating rate of 5°C / min to 1300°C.

[0048] Example

[0049] Preparation Example 1

[0050] 80 wt % of granite powder and 20 wt % of boron oxide powder were mixed evenly, and then calcined at 1000° C. for 2 hours. After cooling, the mixture was ball-milled and sieved to obtain granite glass powder with a size less than 200 meshes.

[0051] Example 1

[0052] Based on the total weight of cerium oxide and neodymium oxide, 30 wt% of cerium oxide and 70 wt% of neodymium oxide are uniformly mixed to obtain a cerium-neodymium mixed oxide;

[0053] Take 0.2 g of dry cerium neodymium oxide and 0.8 g of granite glass powder; add 1×10 6 Bq transuranic nuclides Am / Np / Pu, where Am accounts for 90wt%, Np and Pu each account for 5wt%, add 1.5ml of anhydrous ethanol and mix well;

[0054] Then, the molded body was pressed under 8 MPa for 10 minutes; the molded body was placed in a graphite crucible, and then placed in a quartz tube furnace, and heated to 1300° C. at a rate of 5° C. / min under an inert atmosphere, and kept warm for 2 hours, and naturally cooled to room temperature to obtain a transuranic isotope glass solid body, which was recorded as transuranic isotope glass solid body-I. During the calcination process, the tail gas was absorbed with 0.5 mol / L nitric acid.

[0055] Example 2

[0056] Based on the total weight of cerium oxide and neodymium oxide, 50 wt% of cerium oxide and 50 wt% of neodymium oxide are uniformly mixed to obtain cerium neodymium oxide;

[0057] Take 0.1 g of dry cerium neodymium oxide and 0.9 g of granite glass powder; add 1×10 6 Bq transuranic nuclides Am / Np / Pu, where Am accounts for 90wt%, Np and Pu each account for 5wt%, add 1.5ml of anhydrous ethanol and mix well;

[0058] Then, the molded body is pressed and molded at 9 MPa for 8 minutes; the molded body is placed in a graphite crucible, and then placed in a quartz tube furnace, and heated to 1200° C. at a rate of 10° C. / min under an inert atmosphere, and kept warm for 3 hours, and naturally cooled to room temperature to obtain a transuranic isotope glass solid body, which is recorded as a transuranic isotope glass solid body transuranic isotope glass solid body-II. During the calcination process, the tail gas is absorbed with 0.5 mol / L nitric acid.

[0059] Example 3

[0060] Based on the total weight of cerium oxide and neodymium oxide, 70 wt% of cerium oxide and 30 wt% of neodymium oxide are uniformly mixed to obtain a cerium-neodymium mixed oxide;

[0061] Take 0.2 g of dry cerium neodymium oxide and 0.8 g of granite glass powder; add 1×10 6 Bq transuranic nuclides Am / Np / Pu, where Am accounts for 90wt%, Np and Pu each account for 5wt%, add 1.5ml of anhydrous ethanol and mix well;

[0062] Then, the molded body is pressed and molded at 10 MPa for 5 minutes; the molded body is placed in a graphite crucible, and then placed in a quartz tube furnace, and heated to 1400°C at a rate of 5°C / min under an inert atmosphere, and kept warm for 1 hour, and naturally cooled to room temperature to obtain a transuranic isotope glass solid body, which is recorded as transuranic isotope glass solid body-III. During the calcination process, the tail gas is absorbed with 0.5 mol / L nitric acid.

[0063] Comparative Example 1

[0064] Take 0.2g of dry cerium oxide and 0.8g of granite glass powder; add transuranic nuclides Am / Np / Pu, wherein Am accounts for 90wt%, Np and Pu each account for 5wt%;

[0065] Then, the molded body was pressed and molded at 8 MPa for 10 minutes; the molded body was placed in a graphite crucible, and then placed in a quartz tube furnace, and heated to 1300°C at a rate of 5°C / min under an inert atmosphere, and kept warm for 2 hours, and naturally cooled to room temperature to obtain a transuranic isotope glass solid body, which was recorded as transuranic isotope glass solid body-IV. During the calcination process, the tail gas was absorbed with 0.5 mol / L nitric acid.

[0066] Comparative Example 2

[0067] Take 0.2g of dried neodymium oxide and 0.8g of granite glass powder; add transuranic nuclides Am / Np / Pu, wherein Am accounts for 90wt%, Np and Pu each account for 5wt%;

[0068] Then, the molded body was pressed and molded at 8 MPa for 10 minutes; the molded body was placed in a graphite crucible, and then placed in a quartz tube furnace, and heated to 1300°C at a rate of 5°C / min under an inert atmosphere, and kept warm for 2 hours, and naturally cooled to room temperature to obtain a transuranic isotope glass solid body, which was recorded as transuranic isotope glass solid body-IV. During the calcination process, the tail gas was absorbed with 0.5 mol / L nitric acid.

[0069] XRD test

[0070] The crystal structure of the solid body was tested using Japanese Rigaku model miniflex600, using CuKa rays (wavelength ), step size 0.02°, test range 2theta 10°-70°.

[0071] Depend on Figure 1 It can be seen that the material structure of the transuranium nuclide glass solid body-I is a typical amorphous crystal structure.

[0072] Chemical stability test

[0073] According to the American ASTM C1220-2017 standard, the name of which is "Standard Test Method for Static Leaching of Single Waste Body for Radioactive Waste Treatment", a sample with a known geometric surface area (S) is immersed in a leaching container containing a known volume (V) of leaching agent. The container is sealed and placed in a constant temperature box, and kept static at a set temperature for a specified time. After reaching the specified time, the container is taken out of the constant temperature box, cooled to room temperature and opened; leaching is carried out at 90°C for 14 days to examine the chemical stability. The normalized leaching rate of transuranic nuclides is shown in the following table. The quartz tube is cleaned 3 times with tail gas absorption liquid 0.5mol / L nitric acid, and the cleaning liquid test results are shown in the following table.

[0074] Normalized leaching rate of transuranic nuclides Cleaning fluid test Example 1 <![CDATA[2.45×10 -4 g / m 2 .d]]> Non-radioactive transuranic nuclides Example 2 <![CDATA[3.85×10 -4 g / m 2 .d]]> Non-radioactive transuranic nuclides Example 3 <![CDATA[3.11×10 -4 g / m 2 .d]]> Non-radioactive transuranic nuclides Comparative Example 1 <![CDATA[2.68×10 -2 g / m 2 .d]]> Non-radioactive transuranic nuclides Comparative Example 2 <![CDATA[4.89×10 -3 g / m 2 .d]]> Non-radioactive transuranic nuclides

[0075] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0076] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a transuranium nuclide glass solidified body, characterized in that: The steps include: 1) Mixing granite powder and boron oxide powder and calcining them to obtain granite glass powder; 2) Evenly mixing cerium oxide and neodymium oxide to obtain cerium-neodymium oxide; 3) Mixing the cerium-neodymium oxide and the granite glass powder as a base material, adding transuranic nuclides, adding a mixed medium, mixing evenly, and then pressing and molding to obtain a molded body; 4) calcining the molded body at 1200° C.-1400° C. for 1-3 hours under an inert atmosphere to obtain a transuranic nuclide glass solidified body.

2. The preparation method according to claim 1, wherein In step 1), the mass ratio of the granite powder to the boron oxide powder is granite powder:boron oxide powder=(70-90):(10-30).

3. The preparation method according to claim 1 or 2, wherein In step 1), calcination is performed at 900-1100° C. for 1-3 hours.

4. The preparation method according to claim 1 or 2, wherein: In step 1), the particle size of the granite glass powder is below 200 meshes.

5. The preparation method according to claim 1 or 2, wherein: In step 2), based on the total mass of cerium oxide and neodymium oxide, the content of cerium oxide is 30-70wt%, and the content of neodymium oxide is 30-70wt%.

6. The preparation method according to claim 1 or 2, wherein: In step 3), based on the total weight of cerium-neodymium oxide and granite glass powder, the content of cerium-neodymium oxide is 10-30wt%, and the content of granite glass powder is 70-90wt%.

7. The preparation method according to claim 1 or 2, wherein: In step 3), the transuranic nuclide is one or more of Am, Np and Pu.

8. The preparation method according to claim 1 or 2, wherein: In step 3), the mixed medium is ethanol, and after being mixed evenly, the mixture is pressed at 8-10 MPa for 5-10 minutes to form the mixture.

9. The preparation method according to claim 1 or 2, wherein: In step 4), the temperature is raised to 1200° C.-1400° C. at a heating rate of 5-10° C. / min and calcined.

10. The preparation method according to claim 1 or 2, wherein: Calculated by radiation dose, the total dose per 1g of the transuranium nuclide glass solidified body is 10 6 -10 7 Bq.

Images