Metal ion separation technique using pH adjustment and resin packed column

Abstract

A waste extraction system includes: a deposition tank including a waste inflow port in fluid communication with an upstream section of a main waste path, a solution inlet, and a waste outflow port; a column type effluent tank; an adsorption column located between the precipitation tank and the column effluent tank and in fluid communication with the precipitation tank and the column effluent tank along a main waste path, where the adsorption column contains an ion exchange resin and is located downstream of the precipitation tank; the solution path extends from a solution source to a solution inlet of the settling tank, and an alkaline solution is contained in the solution source; and the particle filtering unit is positioned between the settling tank and the adsorption column and is in fluid communication with the settling tank and the adsorption column.

Description

[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[0002] This disclosure was developed with government support under Contract No. DE-NA0004010 awarded by the U.S. Department of Energy. The government has certain rights in this disclosure. Technical Field

[0003] The present disclosure generally relates to systems and methods for extracting waste radionuclides, for example, systems and methods for extracting waste radionuclides generated during the production of medical isotopes. Background Art

[0004] Current nuclear waste separation technologies include solvent-based extraction, commonly referred to as solvent extraction or liquid-liquid extraction. Solvent extraction is a separation technique in which an extractant containing an organic phase is contacted with an aqueous phase containing metal ions. After mixing, the metal ions are transferred from the aqueous phase to the organic phase. Although the technology is widely used in industry, solvent extraction has many disadvantages, including challenges associated with difficult phase separation, the formation of a heavy phase or "third phase", and the generation of large amounts of hazardous organic waste. From an environmental management perspective, the process's reliance on hazardous aromatic organic solvents poses a particular challenge. Many commercial waste transporters have a low tolerance for the presence of benzene or other aromatic hydrocarbons in solidified waste.

[0005] Therefore, there is a great need for improved methods and systems for separation of nuclear waste, for example, in the production of medical isotopes. Summary of the invention

[0006] According to a first aspect of the present disclosure, a waste extraction system includes: a sedimentation tank, which includes a waste flow inlet, a solution inlet and a waste flow outlet, wherein the waste flow inlet is fluidically connected to an upstream section of a main waste path; a column effluent tank; an adsorption column, which is located between the sedimentation tank and the column effluent tank and is fluidically connected to the sedimentation tank and the column effluent tank along the main waste path, wherein the adsorption column contains an ion exchange resin and is located downstream of the sedimentation tank; a solution path, which extends from a solution source to a solution inlet of the sedimentation tank, wherein the solution source contains an alkaline solution; and a particle filtration unit, which is located between the sedimentation tank and the adsorption column and is fluidically connected to the sedimentation tank and the adsorption column.

[0007] The second aspect comprises the waste extraction system of the first aspect, wherein the alkaline solution comprises NaHCO 3 Solution, Na 2 CO 3 solution or NaHCO 3 / Na 2 CO 3 Solution.

[0008] A third aspect includes the waste extraction system of the first aspect or the second aspect, wherein the waste inlet and the solution inlet of the sedimentation tank are each located at a first end of the sedimentation tank, and the waste outlet is located at a second end of the sedimentation tank opposite to the first end.

[0009] A fourth aspect includes the waste extraction system of the third aspect, wherein the first end of the settling tank is located above the second end of the settling tank.

[0010] The fifth aspect includes the waste extraction system of any of the preceding aspects, wherein the adsorption column includes a waste inlet located at a first end of the adsorption column and a waste outlet located at a second end of the adsorption column, the first end of the adsorption column is opposite to the second end of the adsorption column, and the first end of the adsorption column is located above the second end of the adsorption column.

[0011] A sixth aspect includes the waste extraction system of any preceding aspect, wherein the ion exchange resin comprises ion exchange resin beads having an average diameter of 400 μm to 800 μm.

[0012] A seventh aspect includes the waste extraction system of any preceding aspect, wherein the ion exchange resin comprises a crystalline titanosilicate resin.

[0013] An eighth aspect includes the waste extraction system of any of the preceding aspects, wherein the particle filtration unit comprises a plurality of filters, the plurality of filters comprising a primary filter and a final filter, the primary filter being located upstream of the final filter relative to the waste flow outlet of the sedimentation tank, and the mesh size of the primary filter being larger than the mesh size of the final filter.

[0014] The ninth aspect includes the waste extraction system of the eighth aspect, wherein the multiple filters include one or more intermediate filters located between the primary filter and the final filter, wherein the mesh size of each of the one or more intermediate filters is less than or equal to the mesh size of the primary filter and greater than or equal to the mesh size of the final filter.

[0015] According to the tenth aspect of the present disclosure, a method for extracting radionuclide waste includes: introducing a waste flow from an upstream section of a main waste path into a sedimentation tank; introducing an alkaline solution into the sedimentation tank, thereby increasing the pH of the waste flow and inducing precipitation of a first target radionuclide in the waste flow to form a radionuclide precipitate; introducing the waste flow from the sedimentation tank into an adsorption column; and adsorbing a second target radionuclide in the sedimentation tank onto an ion exchange resin contained in the adsorption column.

[0016] The eleventh aspect includes the method of the tenth aspect, further comprising: collecting the radionuclide precipitate using a particle filtration unit located between the precipitation tank and the adsorption column and in fluid communication with the precipitation tank and the adsorption column.

[0017] A twelfth aspect includes the method of the tenth aspect or the eleventh aspect, wherein the first target radionuclide includes strontium-90 and the second target radionuclide includes cesium-137.

[0018] The thirteenth aspect includes the methods of the tenth to twelfth aspects, wherein the pH of the waste stream in the upstream section of the main waste path is 0 to 3, and the pH of the waste stream entering the adsorption column is 7 to 10.

[0019] The fourteenth aspect includes the method of the tenth to thirteenth aspects, wherein the alkaline solution includes NaHCO 3 Solution, Na 2 CO 3 solution or NaHCO 3 / Na 2 CO 3 Solution.

[0020] The fifteenth aspect includes the methods of the tenth to fourteenth aspects, and further includes: directing a waste stream from the adsorption column to a column effluent tank, wherein the waste stream entering the column effluent tank contains treated waste, the treated waste containing equal to or less than 0.04 Curie per cubic meter of strontium-90 and equal to or less than 1 Curie per cubic meter of cesium-137.

[0021] A sixteenth aspect includes the method of the fifteenth aspect, further comprising: directing the treated waste from the column effluent tank to a waste tank and then solidifying the treated waste.

[0022] A seventeenth aspect includes the methods of aspects ten to sixteen, wherein the waste stream in the upstream section of the main waste path contains a uranium level of at least 500 times the strontium-90 and cesium-137 levels in grams per liter.

[0023] The eighteenth aspect includes the methods of the tenth to seventeenth aspects, wherein the first target radionuclide includes barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium or protactinium, or a combination thereof; and the second target radionuclide includes barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium or protactinium, or a combination thereof.

[0024] A nineteenth aspect includes the method of aspects ten to eighteen, wherein the waste stream in the upstream section of the main waste path contains equal to or greater than 1 g / L uranium.

[0025] The twentieth aspect includes the method of the tenth to nineteenth aspects, wherein the ion exchange resin comprises ion exchange resin beads having an average diameter of 400 μm to 800 μm.

[0026] These and additional features provided by the embodiments described in the present disclosure will be more fully understood in conjunction with the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The embodiments listed in the drawings are illustrative and exemplary and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood in conjunction with the following drawings, in which similar structures are shown by the same reference numerals, wherein:

[0028] Figure 1 schematically illustrates a waste extraction system according to one or more embodiments shown and described in the present disclosure;

[0029] Figure 2 Schematically illustrates a device according to one or more embodiments shown and described in the present disclosure. Figure 1 An exemplary particle filtration unit for a waste extraction system of;

[0030] Figure 3 Schematically illustrates a device according to one or more embodiments shown and described in the present disclosure. Figure 1 Another exemplary particle filtration unit of a waste extraction system;

[0031] Figure 4 Schematically illustrates a device according to one or more embodiments shown and described in the present disclosure. Figure 1 The ion exchange resin is contained in the adsorption column of the waste extraction system. Specific embodiments

[0032] In general, with reference to the accompanying drawings, embodiments of the present disclosure relate to a waste extraction system and method for removing target waste radionuclides from a waste stream formed during the production of medical isotopes. The waste stream contains a variety of radionuclides, such as uranium (U-238), cesium-137 (Cs-137) and strontium-90 (Sr-90). The waste extraction system includes a precipitation tank, an adsorption column and a column effluent tank connected along a main waste path fluid. The waste stream flows through a waste extraction system configured to remove target radionuclides from the waste stream. The precipitation tank promotes a pH adjustment step, and the adsorption column contains an ion exchange resin. The pH adjustment step uses an alkaline solution such as a sodium bicarbonate solution to increase the pH of the waste stream from about 1 to about 8. Increasing the pH of the waste stream causes the first target radionuclide (such as strontium-90) and other fission products to precipitate from the waste stream, which are then filtered and removed. The resulting alkaline uranium-containing effluent is directed from the precipitation tank to the adsorption column. The adsorption column contains an ion exchange resin that adsorbs a second target radionuclide, such as Cs- 137. For example, the ion exchange resin may have a stronger affinity for Cs- 137 than for uranium under alkaline conditions.

[0033] The combination of precipitation and adsorption provided by the waste extraction system provides an efficient and effective system for removing certain radionuclides from a nuclear waste stream. In fact, the waste extraction system does not introduce organic reagents or materials, thereby avoiding the generation of organic waste and simplifying the waste disposal process. In addition, since uranium remains dilute in the waste stream, the waste extraction system does not precipitate or enrich uranium from the solution, thereby reducing criticality concerns. The following will describe embodiments of the waste extraction system and method for radionuclide waste using the waste extraction system, and the same reference numerals may be used in the accompanying drawings to represent the same or similar parts.

[0034] Reference now Figure 1 , shows a waste extraction system 100 according to an exemplary embodiment. The waste extraction system 100 includes a settling tank 120, a particle filtration unit 140, an adsorption column 130, a column effluent tank 150, and a waste tank 155, each of which is fluidly connected to a main waste path 160. The main waste path 160 includes one or more pipes, tubes, or other fluid conveying mechanisms for facilitating the flow of waste streams from the production facility via the settling tank 120, the particle filtration unit 140, and the adsorption column 130 to the column effluent tank 150 and finally to the waste tank 155. One or more pumps 180 are connected to the main waste path 160 to help generate fluid flow within the main waste path 160. In an exemplary operation, an upstream section 162 of the main waste path 160 fluidly connects the waste extraction system 100 to a production area of ​​a medical isotope production facility, and the waste stream contains radionuclide waste generated by the medical isotope production process.

[0035] The precipitation tank 120, the particle filtration unit 140, and the adsorption column 130 are located between the upstream section 162 of the main waste path 160 and the column effluent tank 150, and are in fluid communication with the upstream section 162 of the main waste path 160 and the column effluent tank 150. The precipitation tank 120 is located upstream of the adsorption column 130, so that the waste stream (e.g., the initial waste stream) containing radionuclide waste enters the waste extraction system 100 along the upstream section 162 of the main waste path 160, passes through the precipitation tank 120 in fluid communication with the upstream section 162, passes through the particle filtration unit 140, and then passes through the adsorption column 130 along the main waste path 160. The precipitation tank 120 is in fluid communication with a solution source 175 for introducing an alkaline solution into the precipitation tank 120 to increase the pH of the waste stream and precipitate a first target radionuclide, such as Sr-90, from the waste stream. The adsorption column 130 contains an ion exchange resin 112 (see Figure 4), the ion exchange resin 112 is configured to preferentially adsorb the second target radionuclide, such as Cs-137, from the waste stream after the pH is increased. The column effluent tank 150 is in fluid communication with the adsorption column 130 and, during operation, receives a currently processed waste stream containing reduced levels of the first target radionuclide and the second target radionuclide, and may contain reduced levels of other radionuclides.

[0036] Still refer to Figure 1 The precipitation tank 120 includes a waste inlet 123, a solution inlet 124, and a gas outlet 127, each located at a first end 121 of the precipitation tank 120, and a waste outlet 125 located at a second end 122 of the precipitation tank 120. The waste inlet 123 is in fluid communication with an upstream section 162 of a main waste path 160, and the waste outlet 125 is in fluid communication with an inter-column section 165 of the main waste path 160, which extends from the precipitation tank 120 to the particle filtration unit 140 (the particle filtration unit 140 itself is in fluid communication with the adsorption column 130 through another inter-column section 165). The solution inlet 124 is in fluid communication with a solution path 172 extending from a solution source 175 to the solution inlet 124. The gas outlet 127 is in fluid communication with an exhaust path 128, which provides a channel for exhaust gas formed in the precipitation tank 120 to be discharged from the precipitation tank 120 and flows to an exhaust gas management system. For example, during operation, a sodium bicarbonate solution may contact sulfuric acid in the precipitation tank 120 to generate carbon dioxide gas, which is discharged through the gas outlet 127 .

[0037] During operation, alkaline solutions such as NaHCO 3 Solution, Na 2 CO solution or NaHCO 3 / Na 2 CO 3The mixed solution may be introduced into the precipitation tank 120 via the solution inlet 124. The alkaline solution increases the pH of the waste stream in the precipitation tank 120 to induce precipitation of the first target radionuclide (e.g., Sr-90), thereby forming a radionuclide precipitate. Forming the radionuclide precipitate removes a certain amount of the first target radionuclide in the waste stream. For example, the alkaline solution induces precipitation of 85% or greater of the first target radionuclide initially present in the waste stream (e.g., the waste stream present in the upstream section 162 of the main waste path 160), for example, 85% or greater of the first target radionuclide present in the waste stream, for example, 86% or greater, 87% or greater, 88% or greater, 89% or greater, 90% or greater, 91% or greater, 92% or greater, 93% or greater, 94% or greater, 95% or greater, 96% or greater, 97% or greater, 98% or greater, 99% or greater, 100% or greater, 101% or greater, 102% or greater, 103% or greater, 104% or greater, 105% or greater, 106% or greater, 107% or greater, 108% or greater, 109% or greater, 110% or greater, 111% or greater, 112% or greater, 113% or greater, 114% or greater, 115% or greater, 116% or greater, 117% or greater, 118% or greater, 119% or greater, 120% or greater, 121% or greater, 122% or greater, 123% or greater, 124% or greater, 125% or greater, 126% or greater, 12 % or greater, 91% or greater, 92% or greater, 93% or greater, 93% or greater, 94% or greater, 95% or greater, 95% or greater, 96% or greater, 97% or greater, 97% or greater, 98% or greater, 98.5% or greater, 99% or greater, 99.5% or greater, 99.9% or greater, or a value in a range with any two of these numbers as endpoints.

[0038] Reference now Figures 1 to 3 , the radionuclide precipitate can be collected by the particle filter unit 140. Exemplary particle filter units 140a and 140b are respectively Figure 2 and Figure 3 The particle filter units 140, 140a, 140b include a plurality of filters 141, such as a plurality of inline filters 141a (see Figure 2 ) or multiple concentric filters 141b (see Figure 3), these filters are connected to the waste outlet 125 of the precipitation tank 120, for example, through the inter-column section 165 of the main waste path 160. Each particle filtration unit 140a, 140b includes a filter cavity 145a, 145b; a fluid inlet 168a, 168b connected to the fluid of the precipitation tank 120; and a fluid outlet 169a, 169b connected to the fluid of the adsorption column 130. A plurality of filters 141a, 141b are accommodated in the filter cavity 145a, 145b. A plurality of filters 141 include a primary filter 142 and a final filter 144. Relative to the waste outlet 125 of the precipitation tank 120, the primary filter 142 is located upstream of the final filter 144. The mesh size of the primary filter 142 is larger than the mesh size of the final filter 144. In some embodiments, the plurality of filters 141 includes one or more intermediate filters 146 located between the primary filter 142 and the final filter 144. The mesh size of each of the one or more intermediate filters 146 is smaller than or equal to the mesh size of the primary filter 142 and larger than or equal to the mesh size of the final filter 144. In fact, in some embodiments, the mesh sizes of the plurality of filters 141 gradually become finer from the primary filter 142 to the final filter 144. This facilitates the collection of radionuclide precipitation particles of different sizes in each inline filter, thereby improving the collection efficiency.

[0039] During operation, the waste stream enters the particle filtration unit 140a, 140b through the fluid inlet 168a, 168b, passes through the plurality of filters 141a, 141b and is discharged through the fluid outlet 169a, 169b. The particle filtration unit 140a, 140b may include a shielding shell 149a, 149b containing lead or other radioactive shielding material, and a liner 148a, 148b separating the filter cavity 145a, 145b from the shielding shell 149a, 149b. In some embodiments, the particle filtration unit 140, 140a, 140b is removably connected to the main waste path 160 (e.g., a column section 165 removably connected to the main waste path 160). Thus, the particle filter unit 140, 140a, 140b can be removed from the main waste path 160 to dispose of the collected radionuclide precipitate and the particle filter unit 140, 140a, 140b can be reinstalled, or it can be removed and replaced (e.g., replaced with a new particle filter unit 140, 140a, 140b).

[0040] Reference now Figure 2, the particle filtration unit 140a is a linear particle filtration unit in which the filter (i.e., a plurality of inline filters 141a) is arranged along the Z axis between the fluid inlet 168a and the fluid outlet 169a. The plurality of inline filters 141a includes a primary inline filter 142a and a final inline filter 144a. The primary inline filter 142a is located upstream of the final inline filter 144a relative to the fluid inlet 168a. The mesh size of the primary inline filter 142a is larger than the mesh size of the final inline filter 144a. In some embodiments, the plurality of inline filters 141a includes one or more intermediate inline filters 146a located between the primary inline filter 142a and the final inline filter 144a. The mesh size of each of the one or more intermediate inline filters 146a is less than or equal to the mesh size of the primary inline filter 142a and greater than or equal to the mesh size of the final inline filter 144a. In fact, in some embodiments, the mesh size of the plurality of inline filters 141a gradually decreases from the primary inline filter 142a to the final inline filter 144a, which is conducive to collecting radionuclide precipitation particles of different sizes in each inline filter, thereby improving the collection efficiency.

[0041] Reference now Figure 3, the particle filter unit 140b is a concentric particle filter unit, in which the filters (i.e., a plurality of concentric filters 141b) are arranged concentrically, wherein the radially outward filter surrounds the radially inward filter, and the plurality of concentric filters 141b are each radially outward relative to the fluid inlet 168b. The plurality of concentric filters 141b include a primary concentric filter 142b and a final concentric filter 144b. The primary concentric filter 142b is located upstream of the final concentric filter 144b relative to the fluid inlet 168b of the particle filter unit 140b. In addition, the primary concentric filter 142b and the final concentric filter 144b are both radially outward (e.g., along the r-axis direction) relative to the fluid inlet 168b, so that the fluid (e.g., waste stream) entering the particle filter unit 140b through the fluid inlet 168b passes through the primary concentric filter 142b, then passes through the final concentric filter 144b, and is finally discharged through the fluid outlet 169b. The mesh size of the primary concentric filter 142b is larger than the mesh size of the final concentric filter 144b. In some embodiments, the plurality of concentric filters 141b include one or more intermediate concentric filters 146b radially arranged between the primary concentric filter 142b and the final concentric filter 144b. The mesh size of each of the one or more intermediate concentric filters 146b is less than or equal to the mesh size of the primary concentric filter 142b, and is greater than or equal to the mesh size of the final concentric filter 144b. In fact, in some embodiments, the mesh size of the plurality of concentric filters 141b gradually tapers from the primary concentric filter 142a to the final concentric filter 144b. This is conducive to collecting radionuclide precipitate particles of different sizes in each concentric filter, thereby improving the collection efficiency. The particle filter units 140a, 140b are two exemplary particle filter units 140 that may be used in the waste retrieval system 100, but it should be understood that any particle filter unit sized and configured to remove radionuclide precipitates in the waste retrieval system 100 may be used.

[0042] Reference again Figure 1In some embodiments, the first end 121 of the settling tank 120 is opposite to the second end 122 of the settling tank 120, and the first end 121 of the settling tank 120 is located above the second end 122 of the settling tank 120. This arrangement facilitates gravity-assisted flow of the waste stream through the settling tank 120. Gravity-assisted flow can reduce the pumping pressure and pumping power required for the waste stream to pass through the settling tank 120. In addition, by placing the second end 122 below the first end 121, the waste stream outlet 125 is located below the first end 121 and can be located at the lowest point of the settling tank 120, thereby allowing the radionuclide precipitate to settle by gravity at the second end 122 of the settling tank 120, promoting the flow of the radionuclide precipitate through the waste stream outlet 125 so that it can be collected when the waste stream passes through the particle filtration unit 140.

[0043] The adsorption column 130 includes a waste inlet 134 and a waste outlet 135. The waste inlet 134 is located at the first end 131 of the adsorption column 130, and the waste outlet 135 is located at the second end 133 of the adsorption column 130. The waste inlet 134 is in fluid communication with an inter-column section 165 of a main waste path 160 extending from the precipitation tank 120. The waste outlet 135 is in fluid communication with a column effluent tank 150 extending toward (e.g., directly extending to) the column effluent tank 150 (e.g., Figure 1 The first end 131 of the adsorption column 130 is opposite to the second end 133, and the first end 131 of the adsorption column 130 is located above the second end 133. This arrangement facilitates gravity-assisted flow of the waste stream through the adsorption column 130. Gravity-assisted flow can reduce the pumping pressure and pumping power required for the waste stream to pass through the adsorption column 130. Gravity-assisted flow can also maximize the ion exchange resin 112 (see Figure 4 ) with the waste stream, thereby maximizing the adsorption of the second target radionuclide.

[0044] The column effluent tank 150 is in fluid communication with the main waste path 160, for example, in fluid communication with an inter-column section 165 of the main waste path 160. After passing through the sedimentation tank 120, the particle filtration unit 140 and the adsorption column 130, the treated waste stream enters the column effluent tank 150. The waste tank 155 is in fluid communication with the column effluent tank 150 through the waste tank section 164 of the main waste path 160. The waste generated in the column effluent tank 150 can be directed to the waste tank 155 along the waste tank section 166 for final treatment and transported to an off-site disposal (remove-off site). The final treatment may include curing the resulting waste using concrete to form a cured final waste, which process can be performed in the waste tank 155. In some embodiments, the column effluent tank 150 and the waste tank 155 have the same volume, for example, the volume is 25 gallons to 75 gallons, for example, 30 gallons, 35 gallons, 40 gallons, 45 gallons, 50 gallons, 55 gallons, 60 gallons, 65 gallons, 70 gallons, etc. In other embodiments, the column effluent tank 150 and the waste tank 155 have different volumes, and their volumes can be 25 gallons to 75 gallons. During operation, the processed waste in the column effluent tank 150 can be guided to the waste tank 155 along the waste tank section 164 for final treatment and transported to off-site disposal. For example, the processed waste stream can eventually be disposed of in the form of solid waste. The waste tank 155 can be pre-filled with a curing agent, such as concrete, to facilitate the curing of the processed waste received from the column effluent tank. The waste tank 155 may also include a mixing system that may include a motor and a mixing mechanism to mix the treated waste with a curing agent to form a cured concrete waste that is easier to dispose of than liquid waste.

[0045] After passing through the settling tank 120 and the adsorption column 130, the content of the first target radionuclide and the second target radionuclide in the treated waste is reduced and may contain other radionuclides with reduced content. By removing radionuclides such as the first and second target radionuclides using the waste extraction system 100, the radioactivity level of the resulting waste is lower than the radioactivity level of the initial waste stream. In fact, the target radionuclides account for a disproportionate proportion of the total radioactivity in the initial waste stream. For example, Cs-137 is a gamma-emitting nuclide, so it is desirable to minimize the Cs-137 content in the resulting waste. Adsorption of target radionuclides (such as Cs-137 and Sr-90) allows these target radionuclides to be disposed of separately from the resulting waste (for example, in a minimized volume sealed with concrete).

[0046] Reference now Figure 4, schematically showing a cross-sectional schematic diagram of an adsorption column 130. The ion exchange resin 112 is contained in the adsorption column 130 and may include a cation exchange resin. An exemplary ion exchange resin 112 is an inorganic cation exchange resin, such as a crystalline silicate resin. An example of another ion exchange resin includes a spherical resorcinol-formaldehyde resin (sRF resin). Without intending to be limited by theory, the crystalline silicate resin is configured so that the steric hindrance of metal ions (such as radioactive nuclide ions present in the waste stream) affects the adsorption process. For example, after the crystalline silicate resin is in contact with cesium ions (such as Cs-137), the geometric structure of the crystalline silicate resin preferentially adsorbs cesium ions because the cesium ions have a relatively large radius and hydration diameter. In addition, under alkaline conditions, the crystalline silicate resin preferentially adsorbs Cs-137, so the crystalline silicate resin is effective as an ion exchange resin 112 in the adsorption column 130. Without intending to be limited by theory, the adsorption process of Cs-137 on the crystalline titanosilicate resin is carried out through a two-step mechanism. Specifically, Cs - The hydration and the change in the rigidity of the crystalline titanosilicate resin network work together to accommodate the Cs-137 ions. In some embodiments, the adsorption capacity of the ion exchange resin 112 for Cs-137 is 100 mg to 200 mg of Cs-137 per gram of cation exchange resin 116 (i.e., 100 mg / g to 200 mg / g), such as 125 mg / g to 175 mg / g, such as 105 mg / g, 110 mg / g, 115 mg / g, 120 mg / g, 125 mg / g, 130 mg / g, 135 mg / g, 140 mg / g, 145 mg / g, 150 ... 0 mg / g, 145 mg / g, 150 mg / g, 153 mg / g, 155 mg / g, 157 mg / g, 160 mg / g, 165 mg / g, 170 mg / g, 175 mg / g, 180 mg / g, 185 mg / g, 190 mg / g, 195 mg / g, 200 mg / g, or a range with any two of these values ​​as endpoints, or any value within the range with any two of these values ​​as endpoints.

[0047] By using a cation exchange resin (e.g., a crystalline titanosilicate resin) having a specific adsorption affinity for Cs-137 as the ion exchange resin 112, Cs-137 can be removed from a waste stream having an elevated pH (i.e., the waste stream after passing through the settling tank 120 and the particle filtration unit 140) in the presence of a large amount of uranium. In practice, the waste stream can contain a uranium gram / liter level that is at least 500 times higher than the strontium-90 and cesium-137 gram / liter levels, such as at least 750 times, at least 1000 times, at least 1250 times, at least 1500 times, at least 2000 times, or a multiple within a range having any two of these values ​​as endpoints. In some embodiments, the gram / liter level of uranium included in the initial waste stream can be at least 500 times higher than the gram / liter level of any single radionuclide below, for example at least 750 times, at least 1000 times, at least 1250 times, at least 1500 times, at least 2000 times, or multiples in the range of any two of these values ​​as endpoints: barium, cerium, lanthanum, molybdenum, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, yttrium and zirconium. In addition, uranium can account for 40% to 60% by mass of the total mass of all radionuclides in the initial waste stream. In some embodiments, the initial waste stream comprises 1 gram / liter or more than 1 gram / liter of uranium, for example 1.5 grams / liter, 2 grams / liter or more than 2 grams / liter, 2.5 grams / liter or more than 2.5 grams / liter, 3 grams / liter or more than 3 grams / liter, or values ​​in the range of any two of these values ​​as endpoints. Other radionuclides that may be present in the waste stream and adsorbed by the ion exchange resin 112 include barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium, protactinium, or combinations thereof.

[0048] like Figure 4As shown, in some embodiments, the ion exchange resin 112 includes a plurality of ion exchange resin beads 114, such as crystalline titanosilicate resin beads. The average diameter of the ion exchange resin beads 114 ranges from 200 μm to 1000 μm, such as 400 μm to 800 μm, such as 400 μm, 425 μm, 450 μm, 475 μm, 500 μm, 525 μm, 550 μm, 575 μm, 600 μm, 625 μm, 650 μm, 675 μm, 700 μm, 725 μm, 750 μm, 775 μm, 800 μm, or a range with any two of these values ​​as endpoints. In some embodiments, the plurality of ion exchange resin beads 114 are poured into the adsorption column 130 in a dry state. After entering the adsorption column 130, the ion exchange resin beads 114 can be pretreated with an alkaline solution (such as an aqueous sodium carbonate solution) and added to the adsorption column 130 as a resin slurry (e.g., a resin in an alkaline solution). The pH of the pretreated solution is similar to (e.g., within 1 pH unit) the pH of the initial waste stream. For example, the pretreatment solution can be a sodium carbonate solution with a pH of 8. Pretreatment of the ion exchange resin beads 114 improves the effect and efficiency of separation (i.e., adsorption), especially when the waste stream first enters the adsorption column 130. In addition, the pretreatment of the ion exchange resin beads 114 can be performed at a location away from the waste stream, such as at other locations in the waste extraction system 100 or at other locations in the medical isotope production facility. Therefore, the personnel performing this pretreatment can be away from the waste stream containing radionuclides.

[0049] refer to Figures 1 to 4 , a radionuclide waste extraction method using the waste extraction system 100 will now be described. The method includes directing a waste stream from an upstream section 162 of a main waste path 160 to a precipitation tank 120, and directing an alkaline solution, such as a sodium bicarbonate solution, to the precipitation tank 120. Directing the alkaline solution to the precipitation tank 120 increases the pH of the waste stream. The pH of the waste stream in the upstream section 162 of the main waste path 160 is 0 to 3, such as 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, 2.2, 2.4, 2.5, 2.6, 2.8, 3, or a value in a range with any two of these values ​​as endpoints. Directing the alkaline solution to the precipitation tank 120 can increase the pH of the waste stream so that the pH of the waste stream entering the adsorption column 130 is 7 to 10, for example, 7.2, 7.4, 7.5, 7.6, 7.8, 8, 8.2, 8.4, 8.5, 8.6, 8.8, 9, 9.2, 9.4, 9.5, 9.6, 9.8, 10, or a value within a range with any two of these values ​​as endpoints.

[0050] The alkaline solution can be directed from the solution source 175 to the precipitation tank 120 via the solution inlet 124 along the solution path 172. One or more pumps 180 can be in fluid communication with the solution path 172 to assist the flow of the alkaline solution in the solution path 172 and reach the precipitation tank 120. Increasing the pH of the waste stream induces the precipitation of the first target radionuclide (such as Sr-90) from the waste stream to form a radionuclide precipitate. In some embodiments, the first target radionuclide is Sr-90. However, it should be understood that other radionuclides, such as Ba, La, Ce, Nd, Pr, Rb, Sm, Y, and Zr, can be precipitated in the precipitation tank 120, any of which can be considered as a "first target radionuclide" in the terms of the present disclosure. In addition, it should be understood that the precipitation process is not limited to precipitating a single radionuclide, but any combination of these radionuclides can be precipitated in the same process step.

[0051] Next, the method includes directing the waste stream and the radionuclide precipitate from the precipitation tank 120, for example, along the inter-column section 165 to the particle filtration unit 140. The waste stream passes through the particle filtration unit 140, which removes the radionuclide precipitate from the waste stream. The waste stream then flows from the particle filtration unit 140, for example, along another inter-column section 165 to the adsorption column 130. During operation, the waste stream enters the adsorption column 130 via the waste stream inlet 134, and the ion exchange resin 112 contained in the adsorption column 130 adsorbs the second target radionuclide present in the waste stream, such as Cs-137. By increasing the pH of the waste stream in the precipitation tank 120, the adsorption efficiency of the ion exchange resin 112 can be increased, especially when the ion exchange resin includes a crystalline titanate silicate resin. During operation, the ion exchange resin 112 contained in the adsorption column 130 adsorbs 85% or more of the second target radionuclides initially present in the waste stream (e.g., radionuclides present in the waste stream in the upstream section 162 of the main waste path 160), for example, adsorbs 85% or more of strontium-90 and cesium-137 present in the waste stream, for example, 86% or more, 87% or more, 88% or more, 89% or more , 90% or greater, 91% or greater, 91% or greater, 92% or greater, 93% or greater, 93% or greater, 94% or greater, 95% or greater, 96% or greater, 97% or greater, 98% or greater, 98.5% or greater, 99% or greater, 99.5% or greater, 99.9% or greater, or a value in a range with any two of these values ​​as endpoints.

[0052] Next, the method includes directing the waste stream from the adsorption column 130, for example, along the inter-column section 165 of the main waste path 160 to the column effluent tank 150. In some embodiments, the method also includes directing the resulting waste along the waste tank section to the waste tank 155 for final treatment and transporting it to off-site disposal. As described above, the final treatment of the resulting waste can be solidified by concrete to form a solidified final waste. This makes the resulting waste more compact. The Curie level per cubic meter of the final waste is lower than the Curie level per cubic meter of the resulting waste used to form the final waste. In addition, the radionuclide waste extraction method using the waste extraction system 100 described in the present disclosure is effective in removing a large amount of target radionuclides, thereby maintaining a low level of radioactivity in the final waste formed by the resulting waste. For example, the resulting waste may contain less than 0.25 Curie per cubic meter of Sr-90, for example, less than 0.2 Curie per cubic meter, less than 0.15 Curie per cubic meter, less than 0.1 Curie per cubic meter, less than 0.08 Curie per cubic meter, less than 0.06 Curie per cubic meter, less than 0.05 Curie per cubic meter, less than 0.04 Curie per cubic meter, less than 0.03 Curie per cubic meter, less than 0.02 Curie per cubic meter, less than 0.01 Curie per cubic meter, or a value within a range having any two of these values ​​as endpoints. The resulting waste may also contain less than 10 Curies per cubic meter of Cs-137, such as less than 8 Curies per cubic meter, less than 6 Curies per cubic meter, less than 5 Curies per cubic meter, less than 4 Curies per cubic meter, less than 2 Curies per cubic meter, less than 1 Curie per cubic meter, less than 0.75 Curies per cubic meter, less than 0.5 Curies per cubic meter, less than 0.25 Curies per cubic meter, less than 0.1 Curies per cubic meter, or a value in a range with any two of these values ​​as endpoints. In some embodiments, the resulting waste contains less than 0.04 Curies per cubic meter of Sr-90 and less than 1 Curie per cubic meter of Cs-137. In some embodiments, the final densified waste contains less than 0.04 Curies per cubic meter of Sr-90 and less than 1 Curie per cubic meter of Cs-137.

[0053] Furthermore, the above-mentioned Curie values ​​per cubic meter of waste obtained using the waste extraction system 100 described in the present disclosure can be achieved in the following embodiments, i.e., the initial waste stream (i.e., the waste stream passing through the upstream section 162 of the main waste path 160) contains greater than 150 Curies per cubic meter (e.g., greater than 200 Curies per cubic meter, greater than 300 Curies per cubic meter, greater than 300 Curies per cubic meter, greater than 300 Curies per cubic meter, greater than 500 Curies per cubic meter, greater than 1000 Curies per cubic meter, greater than 2500 Curies per cubic meter, greater than 5000 Curies per cubic meter, greater than 15000 Curies per cubic meter, greater than 10000 Curies per cubic meter, greater than 2500 Curies per cubic meter, greater than 50 ... Cubic meter, or a value in a range with any two of these values ​​as endpoints) of Sr-90 and greater than 44 Curie per cubic meter (for example, greater than 50 Curie per cubic meter, greater than 100 Curie per cubic meter, greater than 250 Curie per cubic meter, greater than 500 Curie per cubic meter, greater than 800 Curie per cubic meter, greater than 1000 Curie per cubic meter, greater than 1500 Curie per cubic meter, greater than 2000 Curie per cubic meter, greater than 3500 Curie per cubic meter, or a value in a range with any two of these values ​​as endpoints) of Cs-137.

[0054] Although Cs-137 and Sr-90 are referred to as target radionuclides in the embodiments described in the present disclosure, other target radionuclides may also be present in the waste stream and may be precipitated by increasing the pH in the precipitation tank 120 and / or adsorbed by the ion exchange resin 112 contained in the adsorption column 130. For example, other target radionuclides that may be present in the waste stream and may be precipitated in the precipitation tank 120 and / or adsorbed by the ion exchange resin 112 include: barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium, protactinium, or a combination thereof.

[0055] The terms "approximately," "about," "substantially," and similar terms used in this disclosure are intended to have a broad meaning consistent with the meanings generally accepted and used by those of ordinary skill in the art to which this disclosure relates. It should be understood that those skilled in the art who review this disclosure will appreciate that these terms are intended to avoid describing certain described and protected features by limiting the scope of these features to the precise numerical values ​​or idealized geometric forms provided. Therefore, these terms should be interpreted as indicating that insubstantial or insignificant modifications or changes to the described and protected subject matter are considered to be within the scope of the disclosure as recorded in the appended claims.

[0056] The term "communication" and its variants used in the present disclosure refer to two elements being directly or indirectly connected to each other. This connection can be static (for example, permanent or fixed) or removable (for example, detachable or releasable). This connection can be two elements that are directly connected to each other, two elements that are connected to each other by using a separate intermediate element and any other intermediate elements that are connected to each other, or two elements that are connected to each other by using an intermediate element that is integrated with one of the two elements to form a single whole. If "communication" or its variants are modified by other terms (for example, direct communication), the general definition of the above-mentioned "communication" can be modified by the common language meaning of other terms (for example, "direct communication" means that two elements are directly connected without any separate intermediate element), thereby resulting in a narrower definition than the general definition of the above-mentioned "communication". This communication can be mechanical, electrical, optical or fluid.

[0057] References to element positions in this disclosure (e.g., "top," "bottom," "above," "below") are only used to describe the orientation of the elements in the drawings. It should be noted that the orientation of the elements may vary according to other exemplary embodiments, and the present disclosure is intended to include these variations.

[0058] Although the drawings and descriptions may show a specific sequence of steps, unless otherwise noted above, the order of these steps may be different from that shown and described. In addition, unless otherwise noted above, two or more steps may be performed in parallel or partially in parallel. Such variations may depend on the selected software and hardware systems and the designer's choice. All of these variations are within the scope of the present disclosure. Similarly, software implementations of the method may be accomplished through standard programming techniques with rule-based logic and other logic to achieve various connection steps, processing steps, comparison steps, and decision steps.

[0059] Although specific embodiments have been illustrated and described in this disclosure, it will be appreciated that various other changes and modifications may be made without departing from the spirit and scope of the subject matter protected. In addition, although various aspects of the subject matter protected have been described in this disclosure, these aspects do not need to be used in combination. Therefore, the appended claims are intended to cover all such changes and modifications within the scope of the subject matter protected.

Claims

1. A waste extraction system comprising: a settling tank comprising a waste flow inlet, a solution inlet, and a waste flow outlet, wherein the waste flow inlet is in fluid communication with an upstream section of a main waste path; Column type outflow tank; an adsorption column located between the settling tank and the column effluent tank and in fluid communication with the settling tank and the column effluent tank along the main waste path, wherein the adsorption column contains an ion exchange resin and is located downstream of the settling tank; a solution path extending from a solution source to the solution inlet of the precipitation tank, wherein the solution source contains an alkaline solution; and The particle filtering unit is located between the precipitation tank and the adsorption column and is in fluid communication with the precipitation tank and the adsorption column.

2. The waste extraction system according to claim 1, wherein: The alkaline solution includes NaHCO3 solution, Na2CO3 solution or NaHCO3 / Na2CO3 solution.

3. The waste extraction system according to claim 1, wherein: The waste inlet and the solution inlet of the precipitation tank are each located at a first end of the precipitation tank, and the waste outlet is located at a second end of the precipitation tank opposite to the first end.

4. The waste extraction system according to claim 3, wherein: The first end of the settling tank is located above the second end of the settling tank.

5. The waste extraction system of claim 1, wherein: The adsorption column comprises a waste inlet located at a first end of the adsorption column and a waste outlet located at a second end of the adsorption column; The first end of the adsorption column is opposite to the second end of the adsorption column; and The first end of the adsorption column is located above the second end of the adsorption column.

6. The waste extraction system according to claim 1, wherein: The ion exchange resin includes ion exchange resin beads having an average diameter of 400 μm to 800 μm.

7. The waste extraction system according to claim 1, wherein: The ion exchange resin includes a crystalline titanosilicate resin.

8. The waste extraction system of claim 1, wherein: The particle filtration unit includes a plurality of filters; The plurality of filters include a primary filter and a final filter; The primary filter is located upstream of the final filter relative to the waste outflow of the settling tank; and The mesh size of the primary filter is larger than the mesh size of the final filter.

9. The waste extraction system according to claim 8, wherein: The plurality of filters include one or more intermediate filters between the primary filter and the final filter, wherein a mesh size of each of the one or more intermediate filters is smaller than or equal to a mesh size of the primary filter and larger than or equal to a mesh size of the final filter.

10. A method for extracting radionuclide waste, the method comprising: directing a waste stream from an upstream section of a main waste path to a settling tank; introducing an alkaline solution into a precipitation tank, thereby increasing the pH of the waste stream and inducing precipitation of a first target radionuclide in the waste stream, thereby forming a radionuclide precipitate; directing the waste stream from the settling tank to an adsorption column; and The second target radioactive nuclide in the precipitation tank is adsorbed onto the ion exchange resin contained in the adsorption column.

11. The method according to claim 10, wherein: The method further includes collecting the radionuclide precipitate using a particle filtration unit located between the precipitation tank and the adsorption column and in fluid communication with the precipitation tank and the adsorption column.

12. The method according to claim 10, wherein: The first target radionuclide includes strontium-90 and the second target radionuclide includes cesium-137.

13. The method according to claim 10, wherein: The pH of the waste stream in the upstream section of the main waste path is between 0 and 3, and the pH of the waste stream entering the adsorption column is between 7 and 10.

14. The method according to claim 10, wherein: The alkaline solution includes NaHCO3 solution, Na2CO3 solution or NaHCO3 / Na2CO3 solution.

15. The method according to claim 10, wherein: The method also includes directing the waste stream from the adsorption column to a column effluent tank, wherein the waste stream entering the column effluent tank comprises treated waste comprising equal to or less than 0.04 Curie per cubic meter of strontium-90 and equal to or less than 1 Curie per cubic meter of cesium-137.

16. The method according to claim 15, wherein: The method also includes directing the treated waste from the column effluent tank to a waste tank and then solidifying the treated waste.

17. The method according to claim 10, wherein: The waste stream in the upstream section of the main waste path comprises a grams per liter level of uranium that is at least 500 times greater than the combined grams per liter level of strontium-90 and cesium-137.

18. The method of claim 10, wherein: The first target radionuclide comprises barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium or protactinium, or a combination thereof; and The second target radionuclide includes barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium or protactinium, or a combination thereof.

19. The method according to claim 10, wherein: The waste stream in the upstream section of the main waste path contains equal to or greater than 1 gram / liter of uranium.

20. The method according to claim 10, wherein: The ion exchange resin includes ion exchange resin beads having an average diameter of 400 μm to 800 μm.

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