Method and system for stepwise chemical separation using resin-packed columns

Abstract

The waste extraction system includes a column set disposed between and fluidly coupled to an upstream portion of the main waste pathway and the column effluent tank, the column set having a uranium adsorption column fluidly coupled along the main waste pathway to an auxiliary adsorption column, the uranium adsorption column being upstream of the auxiliary adsorption column, the waste extraction system further includes a strip waste pathway extending from the uranium adsorption column to the column effluent tank and bypassing the auxiliary adsorption column, an anion exchange resin contained in the uranium adsorption column, and a cation exchange resin contained in the auxiliary adsorption column.

Description

[Technical field]

[0001] (STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT) 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.

[0002] SUMMARY The present disclosure relates generally to systems and methods for extracting waste radionuclides, such as those produced in medical isotope production processes. [Background technology]

[0003] Current technologies for nuclear waste separation include solvent-based extraction, often referred to as solvent extraction or liquid-liquid extraction. Solvent extraction is a separation technique in which an extractant-containing organic phase is contacted with a metal ion-containing aqueous phase. Upon mixing, the metal ions migrate from the aqueous phase to the organic phase. Despite its reliance in industry, solvent extraction has a number of drawbacks, including challenges associated with phase dissociation, the formation of heavy or "third" phases, and the generation of large amounts of hazardous organic waste. Processes that rely on hazardous aromatic organic solvents pose particular challenges from an environmental standpoint. Many commercial waste haulers have a low tolerance for the presence of benzene or other aromatic hydrocarbons in the solidified waste.

[0004] Thus, a need exists for improved methods and systems for nuclear waste separation, for example, in medical isotope production processes. Summary of the Invention

[0005] According to a first aspect of the present disclosure, a waste extraction system includes a column set disposed between and fluidly coupled to an upstream portion of a main waste pathway and a column effluent tank, the column set including a uranium adsorption column fluidly coupled along the main waste pathway to an auxiliary adsorption column upstream of the auxiliary adsorption column, a strip waste pathway extending from the uranium adsorption column to the column effluent tank and bypassing the auxiliary adsorption column, an anion exchange resin contained in the uranium adsorption column, and a cation exchange resin contained in the auxiliary adsorption column.

[0006] A second embodiment includes the waste extraction system of the first embodiment, wherein the auxiliary adsorption column is a first auxiliary adsorption column, and the column set further includes a second auxiliary adsorption column downstream of the first auxiliary adsorption column along the main waste path, the second auxiliary adsorption column containing a cation exchange resin.

[0007] A third embodiment includes the waste extraction system of the first embodiment or the second embodiment, wherein the uranium adsorption column includes a waste stream input and an eluate input, each located at a first end of the uranium adsorption column, where the waste stream input is fluidly coupled to an upstream portion of the main waste pathway, and a waste stream outlet and an eluate outlet, each located at a second end of the uranium adsorption column, where the eluate outlet is fluidly coupled to the strip waste pathway.

[0008] A fourth embodiment includes the waste extraction system of the third embodiment, further including an elution pathway extending from the elution acid source to the elution fluid input.

[0009] A fifth aspect includes the waste extraction system of the third or fourth aspect, wherein the first end of the uranium adsorption column is opposite the second end of the uranium adsorption column and the first end of the uranium adsorption column is above the second end of the uranium adsorption column.

[0010] A sixth embodiment includes the waste extraction system of any of the first to fifth embodiments, wherein the auxiliary adsorption column includes a waste stream input located at a first end of the auxiliary adsorption column and a waste stream output located at a second end of the uranium adsorption column.

[0011] A seventh embodiment includes the waste extraction system of the sixth embodiment, wherein the first end of the uranium adsorption column is opposite the second end of the uranium adsorption column and the first end of the uranium adsorption column is above the second end of the uranium adsorption column.

[0012] An eighth aspect includes the waste extraction system of any of the first to seventh aspects, wherein the cation exchange resin comprises cation exchange resin beads and the anion exchange resin comprises anion exchange resin beads, each of the cation exchange resin beads and the anion exchange resin beads are polymer based, and the cation exchange resin beads and the anion exchange resin beads have an average diameter in the range of 400 μm to 800 μm.

[0013] According to a ninth aspect of the present disclosure, a method for radionuclide waste extraction includes directing a waste stream from an upstream portion of a main waste pathway into a uranium adsorption column of a column set, the column set further including an auxiliary adsorption column fluidly coupled to the uranium adsorption column along the main waste pathway and disposed downstream of the uranium adsorption column, a strip waste pathway extending from the uranium adsorption column to a column waste tank and bypassing the auxiliary adsorption column; adsorbing uranium from the waste stream onto an anion exchange resin contained in the uranium adsorption column; directing the waste stream from the uranium adsorption column into the auxiliary adsorption column; and adsorbing one or more target radionuclides onto a cation exchange resin contained in the auxiliary adsorption column.

[0014] A tenth aspect includes the method of the ninth aspect, wherein the one or more target radionuclides include strontium-90 and cesium-137.

[0015] An eleventh aspect includes the method of the tenth aspect, further including the step of conducting a waste stream from the auxiliary adsorption column to a column effluent tank, wherein the waste stream entering the column effluent tank contains less than 0.04 Curies / cubic meter of Strontium-90 and less than 1 Curie / cubic meter of Cesium-137.

[0016] A twelfth embodiment includes the method of the tenth embodiment or the eleventh embodiment, wherein the waste stream in the upstream portion of the main waste pathway contains uranium at a gram / liter level that is at least 500 times greater than the gram / liter levels of both strontium-90 and cesium-137.

[0017] A thirteenth aspect includes the method of any of the ninth to twelfth aspects, wherein the one or more target radionuclides include barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium, protactinium, or combinations thereof.

[0018] A fourteenth aspect includes the method of any of the ninth to thirteenth aspects, wherein the anion exchange resin contained in the uranium adsorption column adsorbs greater than 90% of the uranium present in the waste stream.

[0019] A fifteenth aspect includes the method of any of the ninth to fourteenth aspects, wherein the waste stream in the upstream portion of the main waste pathway comprises 1 gram / liter or more of uranium.

[0020] A sixteenth aspect includes the method of any of the ninth to fifteenth aspects, wherein the cation exchange resin contained in the auxiliary adsorption column adsorbs greater than 90% of the one or more target radionuclides present in the waste stream.

[0021] A seventeenth aspect includes the method of any of the ninth to sixteenth aspects, wherein the auxiliary adsorbent column is a first auxiliary adsorbent column, and the column set further includes a second auxiliary adsorbent column downstream of the first auxiliary adsorbent column along the main waste path, the second auxiliary adsorbent column containing a cation exchange resin.

[0022] An eighteenth embodiment includes the method of the seventeenth embodiment, wherein the first auxiliary adsorption column and the second auxiliary adsorption column together adsorb greater than 99% of the one or more target radionuclides present in the waste stream.

[0023] A nineteenth aspect includes the method of any of the ninth through eighteenth aspects, further including directing the elution acid through a uranium adsorption column to desorb uranium from the anion exchange resin to form a uranium waste stream, and directing the uranium waste stream along a strip waste path to a column waste tank.

[0024] A twentieth aspect includes the method of any of the ninth to nineteenth aspects, wherein the cation exchange resin comprises cation exchange resin beads and the anion exchange resin comprises anion exchange resin beads, each of the cation exchange resin beads and the anion exchange resin beads are polymer based, and the cation exchange resin beads and the anion exchange resin beads have an average diameter in the range of 400 μm to 800 μm.

[0025] These and additional features provided by the embodiments described herein will be more fully understood in light of the following detailed description taken in conjunction with the drawings, in which:

[0026] The embodiments illustrated in the drawings are illustrative and representative in nature and are not limiting of the subject matter defined by the claims. The following detailed description of exemplary embodiments can be understood when read in conjunction with the following drawings, in which like structures are designated with like numerals and in which: [Brief description of the drawings]

[0027] [Figure 1]1 illustrates a schematic diagram of a waste extraction system according to one or more embodiments shown and described herein; [Diagram 2] 2 illustrates a schematic of an ion exchange resin contained in an adsorption column of a column set of the waste extraction system of FIG. 1 according to one or more embodiments shown and described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Referring generally to the drawings, embodiments of the present disclosure are directed to a waste extraction system and method for the staged removal of target waste radionuclides from a waste stream, for example, from a waste stream formed during a medical isotope production process. The waste stream includes multiple radionuclides, such as Uranium-235 (U-235), Cesium-137 (Cs-137), and Strontium-90 (Sr-90). The waste extraction system includes a column set of adsorption columns containing ion exchange resins configured to selectively adsorb specific radionuclides. The column set is fluidly coupled to a main waste pathway such that the waste stream passes through the column set to reach a column waste tank for final processing.

[0029] The column set includes a uranium adsorption column containing an anion exchange resin configured to selectively adsorb uranium and one or more auxiliary adsorption columns disposed downstream of the uranium adsorption column along the primary waste pathway. The one or more auxiliary adsorption columns contain a cation exchange resin configured to selectively adsorb one or more target radionuclides, such as Cs-137 and Sr-90. The waste extraction system also includes a waste strip pathway fluidly connecting the uranium adsorption column to a column waste tank and bypassing the one or more auxiliary adsorption columns. The uranium adsorption column provides a pathway for removing uranium, such as U-235, from the waste stream such that the waste stream passing through the one or more auxiliary adsorption columns contains minimal uranium. This allows the one or more auxiliary adsorption columns to remove other target radionuclides, such as Cs-137 and Sr-90, from the waste stream that may be present in smaller amounts than uranium in the initial waste stream. Embodiments of a waste extraction system and a method of radionuclide waste extraction using the waste extraction system are described herein. Whenever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[0030] 1 and 2, a waste extraction system 100 is shown according to an exemplary embodiment. The waste extraction system 100 comprises a column set 110 comprising two or more adsorption columns packed with ion exchange resins configured to adsorb radionuclides. The column set 110 includes a uranium adsorption column 120 containing an anion exchange resin 112 and one or more auxiliary adsorption columns 130 containing a cation exchange resin 116. The column set 110 is fluidly coupled to a main waste pathway 160 comprising one or more pipes, tubing, or other fluid transfer mechanisms for facilitating the flow of a waste stream from a manufacturing facility through the column set 110 to a column effluent tank 150 and ultimately to a waste tank 155. One or more pumps 180 are coupled to the main waste pathway 160 to assist in generating fluid flow within the main waste pathway 160. In one example operation, the upstream portion 162 of the main waste pathway 160 fluidly connects the waste extraction system 100 to a manufacturing area of ​​a medical isotope production facility, with the waste stream comprising radionuclide waste generated by the medical isotope production process.

[0031] The column set 110 is disposed between and fluidly coupled to an upstream portion 162 of a primary waste pathway 160 and a column effluent tank 150. In operation, a waste stream containing radionuclide waste enters the waste extraction system 100 along the upstream portion 162 of the primary waste pathway 160 (e.g., an initial waste stream). The uranium adsorption column 120 is fluidly coupled to the upstream portion 162 of the primary waste pathway 160 and is disposed along the primary waste pathway 160 upstream of the one or more auxiliary adsorption columns 130. In operation, the waste stream traverses the uranium adsorption column 120 and then traverses the one or more auxiliary adsorption columns 130 along the primary waste pathway 160. In operation, the anion exchange resin 112 contained in the uranium adsorption column 120 adsorbs uranium, such as U-235, from the waste stream, reducing the uranium in the waste stream entering the one or more auxiliary adsorption columns 130. And, the cation exchange resin 116 contained in one or more auxiliary adsorption columns 130 adsorbs one or more target radionuclides, such as Cs-137 and Sr-90, from the waste stream.

[0032] By removing uranium from the waste stream in the uranium adsorption column 120, the one or more auxiliary adsorption columns 130 may more efficiently and effectively adsorb other radionuclides of interest. Without intending to be limited by theory, uranium present in the initial waste stream will be adsorbed by the cation exchange resin 116 in the auxiliary adsorption column 130 (along with one or more radionuclides of interest), and a large relative amount of uranium may cause the cation exchange resin 116 to reach its adsorption limit before removing a desired amount of the radionuclides of interest. For example, the initial waste stream may contain gram / liter levels of uranium at least 500 times or more than the gram / liter levels of both strontium-90 and cesium-137, such as at least 750 times or more, at least 1000 times or more, at least 1250 times or more, at least 1500 times or more, at least 2000 times or more, or a multiplier within a range having any two of these values ​​as endpoints. In some embodiments, the initial waste stream may include uranium at a gram / liter level of at least 500 times or more the gram / liter level of any individual of the following radionuclides: barium, cerium, lanthanum, molybdenum, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, yttrium, and zirconium, such as at least 750 times or more, at least 1000 times or more, at least 1250 times or more, at least 1500 times or more, at least 2000 times or more, or a multiplier in a range having any two of these values ​​as endpoints. Further, uranium may comprise 40%-60% of the mass of the total radionuclides in the initial waste stream.

[0033] In some embodiments, the initial waste stream contains uranium at 1 gram / liter or more, such as 1.5 grams / liter, 2 grams / liter or more, 2.5 grams / liter or more, 3 grams / liter or more, and values ​​within a range having any two of these values ​​as endpoints. Although Cs-137 and Sr-90 are referred to as the radionuclides of interest in the embodiments described herein, other radionuclides of interest may be present in the waste stream and adsorbed by the cation exchange resin 116. For example, other radionuclides of interest that may be present in the waste stream and adsorbed by the cation exchange resin 116 include barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium, protactinium, or combinations thereof.

[0034] The uranium adsorption column 120 includes a waste stream input 123 and an eluate input 124, each located at a first end 121 of the uranium adsorption column 120, and a waste stream output 125 and an eluate output 126, each located at a second end 122 of the uranium adsorption column 120. The waste stream input 123 is fluidly coupled to an upstream portion 162 of a main waste pathway 160, and the waste stream output 125 is fluidly coupled to an inter-column portion 165 of the main waste pathway 160. The main waste pathway 160 may include multiple inter-column portions 165, which are portions of the main waste pathway 160 between adjacent adsorption columns of the column set 110 and between the final adsorption column (e.g., the second auxiliary adsorption column 132b in the embodiment shown in FIG. 1) and the column effluent tank 150. It should be understood that additional inter-column portions 165 are also contemplated in embodiments that include processing components between the column set 110 and the column effluent tank 150. Additionally, in some embodiments, the first end 121 of the uranium adsorption column 120 is opposite the second end 122 of the uranium adsorption column 120, and the first end 121 of the uranium adsorption column 120 is above the second end 122 of the uranium adsorption column 120. This orientation facilitates gravity-assisted flow of the waste stream through the uranium adsorption column 120. Gravity-assisted flow may reduce the pump pressure and pump power required to drive the waste stream through the uranium adsorption column 120. Gravity-assisted flow may also maximize contact between the anion exchange resin 112 and the waste stream, maximizing uranium adsorption.

[0035] 1, the one or more auxiliary adsorbent columns 130 include a first auxiliary adsorbent column 132a and a second auxiliary adsorbent column 132b fluidly coupled along the main waste pathway 160, for example, by an inter-column section 165 of the main waste pathway 160. The second auxiliary adsorbent column 132b is positioned downstream of the first auxiliary adsorbent column 132a such that the waste stream traverses the first auxiliary adsorbent column 132a before traversing the second auxiliary adsorbent column 132b. Each auxiliary adsorbent column 132a, 132b includes a waste stream input 134a, 134b and a waste stream output 135a, 135b. The waste stream inputs 134a, 134b are located at the first ends 131a, 131b of each auxiliary adsorption column 132a, 132b, and the waste stream outputs 135a, 135b are located at the second ends 133a, 133b of each auxiliary adsorption column 132a, 132b. Additionally, in some embodiments, the first ends 131a, 131b of each auxiliary adsorption column 132a, 132b are opposite the second ends 133a, 133b, and the first ends 131a, 131b are above the second ends 133a, 133b. This orientation promotes gravity-assisted flow of the waste stream through each auxiliary adsorption column 132a, 132b. Gravity-assisted flow may reduce the pump pressure and pump power required to drive the waste stream through one or more auxiliary adsorption columns 130. Gravity assisted flow may also maximize contact of the cation exchange resin 116 with the waste stream to maximize adsorption of the radionuclides of interest.

[0036] Although two auxiliary adsorbent columns 132a, 132b are shown, it should be understood that additional adsorbent columns may be included to adsorb additional amounts of the target radionuclides. Alternatively, a column set 110 having only the first auxiliary adsorbent column 132a and excluding the second auxiliary adsorbent column 132b is contemplated. Of course, in such an alternative embodiment, the volume of the first auxiliary adsorbent column 132a may be doubled (along with doubling the volume of the cation exchange resin 116 in the first auxiliary adsorbent column 132a). While this would facilitate removal of the same level of the target radionuclides, doubling the volume of the first auxiliary adsorbent column 132a may be difficult in waste extraction system 100 with size and design constraints. Furthermore, increasing the volume of the first auxiliary adsorbent column 132a increases the pump pressure required to move the waste stream through the first auxiliary adsorbent column 132a, since the flow resistance increases as the size of the first auxiliary adsorbent column 132a increases.

[0037] 1 , the eluate input 124 of the uranium adsorption column 120 is fluidly coupled to an elution path 172 that extends from an elution acid source 175 to the eluate input 124. The eluate outlet 126 is fluidly coupled to a strip waste path 170 that extends from the uranium adsorption column 120 to the column waste tank 150 and provides a fluid path from the uranium adsorption column 120 to the column waste tank 150 while bypassing the one or more auxiliary adsorption columns 130. One or more of the pumps 180 may be fluidly coupled to the strip waste path 170 to help facilitate the flow of fluid within the strip waste path 170. The strip waste path 170 provides a path for uranium removed from the initial waste stream (e.g., uranium waste stream) by the uranium adsorption column 120 to reach the column waste tank 150 without traversing the one or more auxiliary adsorption columns 130.

[0038] In operation, the elution acid may be directed through the uranium adsorption column 120 via the elution inlet 124. The elution acid flows through the uranium adsorption column 120 and desorbs uranium from the anion exchange resin 112 to form a uranium waste stream. The uranium waste stream may be directed from the uranium adsorption column 120 via the elution outlet 126 into a strip waste path 170 where the uranium waste stream is directed to a column waste tank 150. By flowing through the strip waste path 170, the uranium waste stream bypasses one or more auxiliary adsorption columns 130, thereby allowing the auxiliary adsorption columns 130 to adsorb other target radionuclides, such as Cs-137 and Sr-90, present in the initial waste stream at lower levels than uranium.

[0039] As shown in FIG. 1, the column waste tank 150 is fluidly coupled to both the main waste pathway 160 and the strip waste pathway 170. Thus, the treated waste stream from the auxiliary adsorption column 130 mixes with the uranium waste stream from the uranium adsorption column 120 in the column waste tank 150 to form a resultant waste. The waste tank 155 is fluidly coupled to the column waste tank 150 by the waste tank portion 166 of the main waste pathway 160. The resultant waste in the column waste tank 150 will be directed along the waste tank portion 166 into the waste tank 155 for final off-site treatment and removal. This final treatment may include concreting the resultant waste to form a solid final waste. This may occur in the waste tank 155. In some embodiments, the column waste tank 150 and the waste tank 155 are of the same volume, for example, in the range of 25 gallons to 75 gallons, such as 50 gallons. In other embodiments, the column effluent tank 150 and the waste tank 155 are of different volumes and may have volumes ranging from 25 gallons to 75 gallons.

[0040] The resulting waste contains the uranium that was separated earlier, but the radionuclides of interest have been removed. By removing the radionuclides of interest using the waste extraction system 100, the resulting waste contains a lower level of radioactivity than the initial waste stream. Naturally, the radionuclides of interest contribute a disproportionate amount of the total radioactivity in the initial waste stream. For example, since Cs-137 is a gamma ray emitting nuclide, it is desirable to minimize the amount of Cs-137 in the resulting waste. By adsorbing the radionuclides of interest, such as Cs-137 and Sr-90, these radionuclides of interest can be disposed of separately from the resulting waste in a minimal volume, e.g., sealed in concrete.

[0041] 2, a schematic cross-sectional view of a column set 110 is illustrated. As illustrated in FIG. 2, in some embodiments, the anion exchange resin 112 comprises a plurality of anion exchange resin beads 114, and the cation exchange resin 116 comprises a plurality of cation exchange resin beads 118. The anion exchange resin beads 114 and the cation exchange resin beads 118 are of average diameter ranging from 200 μm to 1000 μm, e.g., 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 any range having any two of these values ​​as endpoints.

[0042] In some embodiments, a plurality of anion exchange resin beads 114 and cation exchange resin beads 118 are dry poured into the adsorption column of the column set 110. The anion exchange resin beads 114 and cation exchange resin beads 118 may be preconditioned once in the auxiliary adsorption column 132 by passing two or more column volumes of a pretreatment acid, such as sulfuric acid, through the adsorption column of the column set 110 before introducing the waste stream into the column set 110. In other embodiments, the anion exchange resin beads 114 and cation exchange resin beads 118 may be pretreated with an acid, such as sulfuric acid, and added to the column set 110 as a resin slurry (e.g., resin in acid). The pretreatment acid comprises a pH equivalent to the initial waste stream (e.g., within one unit of it). For example, the pretreatment acid may comprise sulfuric acid with a pH of 1. The step of pretreating the anion exchange resin beads 114 and cation exchange resin beads 118 may be performed at a location away from the waste stream, such as a different location in the waste extraction system 100, or at a different location in the medical isotope production facility. This allows personnel performing this pretreatment to be located away from the radionuclide-containing waste stream.

[0043] In some embodiments, each of the anion exchange resin 112 and the cation exchange resin 116 is polymer-based. The anion exchange resin 112 can be comprised of a weakly basic anion exchange resin or a strongly basic anion exchange resin. The cation exchange resin 116 can be comprised of a strongly acidic cation exchange resin. The anion exchange resin 112 and the cation exchange resin 116 have a combination of porosity that contributes to adsorption capacity and chemical functionality that contributes to selectivity. Furthermore, the cation exchange resin 116 has a preference for adsorption of Cs-137 and Sr-90 compared to uranium, making the cation exchange resin 116 effective in the auxiliary adsorption column 130. Examples of anion exchange resins 112 include Amberlite™ resin and DIAON™ resin. Examples of cation exchange resins 116 include SACMP (strong acid cation macroporous polystyrene) resins (such as ResinTech® SACMP from ResinTech Inc.) and AMP-PAN (ammonium molybdophosphate polyacrylonitrile) resins.

[0044] In some embodiments, the cation exchange resin 116 has a Cs-137 concentration in the range of 100 mg 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, e.g., 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 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 value within a range having any two of these numerical values ​​as endpoints. In some embodiments, the cation exchange resin 116 has an adsorption capacity of Sr-90 in the range of 0.1 mg (i.e., 0.1 mg / g) to 1 mg / g of Sr-90 per gram of cation exchange resin 116, such as in the range of 0.15 mg / g to 0.5 mg / g, e.g., 0.15 mg / g, 0.2 mg / g, 0.25 mg / g, 0.3 mg / g, 0.35 mg / g, 0.4 mg / g, 0.45 mg / g, 0.5 mg / g, 0.55 mg / g, 0.6 mg / g, 0.65 mg / g, 0.7 mg / g, 0.75 mg / g, 0.8 mg / g, 0.85 mg / g, 0.9 mg / g, 0.95 mg / g, 1 mg / g, or a value within a range having any two of these values ​​as endpoints. Still further, in some embodiments, the anion exchange resin 112 has an adsorption capacity of uranium (e.g., U-235) in the range of 85 mg U per gram of anion exchange resin 112 (i.e., 85 mg / g) to 165 mg / g, such as in the range of 115 mg / g to 140 mg / g, e.g., 85 mg / g, 90 mg / g, 95 mg / g, 100 mg / g, 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 mg / g, 155 mg / g, 160 mg / g, 165 mg / g, or a value within a range having any two of these values ​​as endpoints.

[0045] 1 and 2, a method of radionuclide waste extraction using waste extraction system 100 will now be described. First, the method comprises directing a waste stream from an upstream portion 162 of main waste pathway 160 into uranium adsorption column 120 of column set 110. Next, the method comprises adsorbing uranium from the waste stream onto an anion exchange resin 112 contained within uranium adsorption column 120. In operation, the waste stream enters uranium adsorption column 120 via waste stream input 123, and anion exchange resin 112 contained within uranium adsorption column 120 adsorbs uranium present in the waste stream and removes the uranium from the waste stream. The waste stream then exits uranium adsorption column 120 via waste stream outlet 125 and flows to one or more auxiliary adsorption columns 130 at a lower level of uranium than was present in the waste stream upon entry into uranium adsorption column 120. For example, the anion exchange resin 112 contained in the uranium adsorption column 120 adsorbs 85% or more of the uranium present in the waste stream, e.g., 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, or a range having any two of these values ​​as endpoints.

[0046] The method then includes directing the waste stream (e.g., a depleted uranium waste stream) from the uranium adsorption column 120 into the first auxiliary adsorption column 132a, e.g., along intercolumn section 165. During operation, the waste stream (e.g., a depleted uranium waste stream) enters the first auxiliary adsorption column 132a through waste stream input 134a, and the cation exchange resin 116 contained within the first auxiliary adsorption column 132a adsorbs target radionuclides, such as Sr-90 and Cs-137, present in the depleted uranium waste stream. During operation, the cation exchange resin 116 contained in the first auxiliary adsorption column 132a adsorbs 85% or more of the one or more target radionuclides initially present in the waste stream (e.g., present in the waste stream in the upstream portion 162 of the main waste pathway 160), e.g., 86% or more, 87% or more, 88% or more, 89% or more, 90% or more, 91% or more, 92% or more, 93% or more, 94% or more, 95% or more, 96% or more, or a value within a range having any two of these values ​​as endpoints.

[0047] The depleted uranium waste stream then exits the first auxiliary adsorbent column 132a through waste stream outlet 135a and enters inter-column section 165 of main waste pathway 160. After exiting the first auxiliary adsorbent column 132a, the waste stream may be directed to either the second auxiliary adsorbent column 132b (e.g., in embodiments including two or more auxiliary adsorbent columns 130, such as the embodiment shown in FIG. 1) or to a column effluent tank 150 (e.g., in embodiments including a single auxiliary adsorbent column 130). In embodiments including a second auxiliary adsorbent column 132b, once the depleted uranium waste stream enters the second auxiliary adsorbent column 132b, the method includes adsorbing an additional amount of one or more target radionuclides present in the depleted uranium waste stream onto the cation exchange resin 116 contained in the second auxiliary adsorbent column 132b. By adsorbing the additional amount of the target radionuclides in the second auxiliary adsorption column 132b, the first auxiliary adsorption column 132a and the second auxiliary adsorption column 132b collectively adsorb 95% or more of the one or more target radionuclides originally present in the waste stream (e.g., present in the waste stream in the upstream portion 162 of the main waste pathway 160), e.g., 95% or more of the Sr-90 and Cs-137 that were present in the waste stream, such as 96% or more, 97% or more, 98% or more, 98.5% or more, 99% or more, 99.5% or more, 99.9% or more, or a range having any two of these values ​​as endpoints. Naturally, the first auxiliary adsorption column 132a acts as a coarse filter for the target radionuclides and the second auxiliary adsorption column 132b acts as a fine filter for the target radionuclides.

[0048] 1 and 2, the method further comprises removing uranium from the uranium adsorption column 120 and directing the uranium along a strip waste pathway 170 to a column waste tank 150. The removal process may comprise directing an elution acid, such as sulfuric acid, into the uranium adsorption column 120 to desorb the uranium from the anion exchange resin 112 to form a uranium waste stream. The elution acid may include sulfuric acid. The elution acid may be directed from an elution acid source 175 along an elution pathway 172 through the elution input 124 into the uranium adsorption column 120. One or more of the pumps 180 may be fluidly coupled to the elution pathway 172 to assist in facilitating the flow of the elution acid in the elution pathway 172 and into the uranium adsorption column 120. After desorption, the uranium waste stream may be directed from the uranium adsorption column 120 along the strip waste pathway 170 to the column waste tank 150. In the column waste tank 150, the treated waste stream from the one or more auxiliary adsorption columns 130 mixes with the uranium waste stream from the uranium adsorption column 120 to form a resultant waste. In some embodiments, the method further comprises directing the resultant waste along waste tank section 166 to waste tank 155 for final external processing and removal.

[0049] As mentioned above, in final processing, the resulting waste may be concreted to form a solid final waste, which results in a high concentration of the resulting waste. As such, the final waste contains a higher level of curies per cubic meter than the resulting waste used to form the final waste. However, the method of radionuclide waste extraction using the waste extraction system 100 described herein is effective in removing a majority of the radionuclides of interest, so that even after concentration, the final waste formed from the resulting waste retains a low level of radioactivity. For example, the resulting waste may contain less than 0.25 Curies / cubic meter of Sr-90, e.g., less than 0.2 Curies / cubic meter, less than 0.15 Curies / cubic meter, less than 0.1 Curies / cubic meter, less than 0.08 Curies / cubic meter, less than 0.06 Curies / cubic meter, less than 0.05 Curies / cubic meter, less than 0.04 Curies / cubic meter, less than 0.03 Curies / cubic meter, less than 0.02 Curies / cubic meter, less than 0.01 Curies / cubic meter, or any value of Sr-90 in a range having any two of these values ​​as endpoints. The resulting waste may also contain less than 10 curies / cubic meter of Cs-137, such as less than 8 curies / cubic meter, less than 6 curies / cubic meter, less than 5 curies / cubic meter, less than 4 curies / cubic meter, less than 2 curies / cubic meter, less than 1 curie / cubic meter, less than 0.75 curies / cubic meter, less than 0.5 curies / cubic meter, less than 0.25 curies / cubic meter, less than 0.1 curie / cubic meter, or any value of Cs-137 within a range having any two of these values ​​as endpoints. In some embodiments, the resulting waste contains less than 0.04 curies / cubic meter of Sr-90 and less than 1 curie / cubic meter of Cs-137. In some embodiments, the final concentrated waste contains less than 0.04 curies / cubic meter of Sr-90 and less than 1 curie / cubic meter of Cs-137.

[0050] Moreover, the above values ​​of Curies / cubic meter in the resulting waste may be achieved with the waste extraction system 100 described herein in the following embodiments, in which the initial waste stream (i.e., the waste stream traversing the upstream portion 162 of the main waste pathway 160) has a Sr-90 of greater than 150 Curies / cubic meter, e.g., greater than 200 Curies / cubic meter, greater than 300 Curies / cubic meter, greater than 300 Curies / cubic meter, greater than 400 Curies / cubic meter, greater than 500 Curies / cubic meter, greater than 1000 Curies / cubic meter, greater than 2500 Curies / cubic meter, greater than 5000 Curies / cubic meter, or any two of these values ​​as endpoints. and including any value of Sr-90 in the range defined above, and including greater than 44 Curies / cubic meter of Cs-137, such as greater than 50 Curies / cubic meter, greater than 100 Curies / cubic meter, greater than 250 Curies / cubic meter, greater than 500 Curies / cubic meter, greater than 800 Curies / cubic meter, greater than 1000 Curies / cubic meter, greater than 1500 Curies / cubic meter, greater than 2000 Curies / cubic meter, greater than 3500 Curies / cubic meter, or any value of Cs-137 in a range having any two of these values ​​as endpoints.

[0051] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have broad meanings consistent with common and accepted usage by those of ordinary skill in the art to which the subject matter of the present disclosure pertains. These terms should be understood by those of ordinary skill in the art who consider this disclosure to allow for the description of certain features described in the detailed description and claimed herein without limiting the scope of those features to given precise numerical values ​​or idealized geometric configurations. These terms should therefore be interpreted as indicating that insubstantial or minor variations or modifications of the subject matter described in the detailed description and claimed herein are considered to be within the scope of the disclosure set forth in the ensuing claims.

[0052] As used herein, the term "coupled" and variations thereof mean that two members are joined to one another directly or indirectly. The joining can be static (e.g., permanent or fixed) or movable (e.g., removable or releasable). The joining can be achieved by the two members being directly joined to one another, by the two members being joined to one another using a separate intervening member and an additional intermediate member joined to one another, or by the two members being joined to one another using an intervening member integrally formed as a single unit with one of the two members. When "coupled" or variations thereof are modified by an additional term (e.g., directly coupled), the general definition of "coupled" given above is modified by the plain linguistic meaning of the additional term (e.g., "directly coupled" means joining of two members without any separate intervening member), resulting in a narrower definition than the general definition of "coupled" given above. The joining can be mechanical, electrical, optical, or fluid.

[0053] References to the location of elements herein (e.g., "top", "bottom", "upper", "lower") are merely used to describe the orientation of various elements in the drawings. It should be noted that the orientation of various elements may vary in other exemplary embodiments, and such variations are intended to be encompassed by the present disclosure.

[0054] Although the figures and detailed description may show a particular order of method steps, the order of the steps may be different from that shown and described unless specified otherwise. Also, two or more steps may be performed simultaneously or simultaneously in parallel unless specified otherwise. Such variations may depend, for example, on the software and hardware selected and on the designer's choice. All such variations are within the scope of this disclosure. Similarly, software implementations of the described methods may be realized by standard programming techniques with rule-based logic and other logic implementing the various connection, processing, comparison and decision steps.

[0055] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications can be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the following claims cover all such changes and modifications that are within the scope of the claimed subject matter.

Claims

1. 1. A waste extraction system comprising: a column set disposed between and fluidly coupled to an upstream portion of a primary waste path and a column effluent tank, the column set comprising a uranium adsorption column fluidly coupled to an auxiliary adsorption column along the primary waste path, the uranium adsorption column being upstream of the auxiliary adsorption column; a strip waste path extending from the uranium adsorption column to the column waste tank and bypassing the auxiliary adsorption column; an anion exchange resin contained in the uranium adsorption column; a cation exchange resin contained in the auxiliary adsorption column; 1. A waste extraction system comprising:

2. 2. The waste extraction system of claim 1, wherein the auxiliary adsorption column is a first auxiliary adsorption column, the column set further comprising a second auxiliary adsorption column downstream of the first auxiliary adsorption column along the main waste path, the second auxiliary adsorption column containing a cation exchange resin.

3. The uranium adsorption column comprises: a waste stream input and an eluate input, each located at a first end of the uranium adsorption column, the waste stream input being fluidly coupled to the upstream portion of the main waste pathway; a waste stream outlet and an eluate outlet, respectively, located at a second end of the uranium adsorption column, the eluate outlet being fluidly coupled to the strip waste path; 10. The waste extraction system of claim 1, comprising:

4. 4. The waste extraction system of claim 3, further comprising an elution path extending from a elution acid source to the elution fluid input.

5. 4. The waste extraction system of claim 3, wherein the first end of the uranium adsorption column is opposite the second end of the uranium adsorption column and the first end of the uranium adsorption column is above the second end of the uranium adsorption column.

6. 2. The waste extraction system of claim 1, wherein the auxiliary adsorption column comprises a waste stream input located at a first end of the auxiliary adsorption column and a waste stream output located at a second end of the uranium adsorption column.

7. 7. The waste extraction system of claim 6, wherein the first end of the auxiliary adsorption column is opposite the second end of the auxiliary adsorption column and the first end of the auxiliary adsorption column is above the second end of the auxiliary adsorption column.

8. the cation exchange resin comprises cation exchange resin beads; the anion exchange resin comprises anion exchange resin beads; each of the cation exchange resin beads and the anion exchange resin beads is polymer-based; 2. The waste extraction system of claim 1, wherein the cation exchange resin beads and the anion exchange resin beads have an average diameter in the range of 400 μm to 800 μm.

9. 1. A method for radionuclide waste extraction comprising the steps of: directing the waste stream from an upstream portion of the primary waste pathway into a uranium adsorption column of the column set; the column set further comprising an auxiliary adsorption column fluidly coupled to the uranium adsorption column along the primary waste path and disposed downstream of the uranium adsorption column; a strip waste path extends from the uranium adsorption column to a column waste tank and bypasses the auxiliary adsorption column; adsorbing uranium from the waste stream onto an anion exchange resin contained in the uranium adsorption column; directing the waste stream from the uranium adsorption column into the auxiliary adsorption column; adsorbing one or more target radionuclides onto a cation exchange resin contained in the auxiliary adsorption column; A method for providing the above.

10. 10. The method of claim 9, wherein the one or more radionuclides of interest include strontium-90 and cesium-137.

11. 11. The method of claim 10, further comprising the step of conducting the waste stream from the auxiliary adsorption column to the column effluent tank, the waste stream entering the column effluent tank containing less than 0.04 Curies / cubic meter of Strontium-90 and less than 1 Curie / cubic meter of Cesium-137.

12. 11. The method of claim 10, wherein the waste stream in the upstream portion of the main waste pathway contains uranium at a gram / liter level at least 500 times greater than the gram / liter levels of both strontium-90 and cesium-137.

13. 10. The method of claim 9, wherein the one or more radionuclides of interest comprise barium, cerium, cesium, lanthanum, molybdenum, sodium, neodymium, palladium, praseodymium, rubidium, rhodium, ruthenium, samarium, strontium, yttrium, zirconium, protactinium, or combinations thereof.

14. 10. The method of claim 9, wherein the anion exchange resin contained in the uranium adsorption column adsorbs greater than 90% of the uranium present in the waste stream.

15. 10. The method of claim 9, wherein the waste stream in the upstream portion of the main waste pathway comprises 1 gram / liter or more of uranium.

16. 10. The method of claim 9, wherein the cation exchange resin contained in the auxiliary adsorption column adsorbs greater than 90% of the one or more target radionuclides present in the waste stream.

17. 10. The method of claim 9, wherein the auxiliary adsorption column is a first auxiliary adsorption column, the column set further comprising a second auxiliary adsorption column downstream of the first auxiliary adsorption column along the main waste path, the second auxiliary adsorption column containing a cation exchange resin.

18. 20. The method of claim 17, wherein the first auxiliary adsorption column and the second auxiliary adsorption column collectively adsorb greater than 99% of the one or more target radionuclides present in the waste stream.

19. directing the elution acid through the uranium adsorption column to desorb uranium from the anion exchange resin and form a uranium waste stream; directing the uranium waste stream along the strip waste path to the column waste tank; The method of claim 9 further comprising:

20. the cation exchange resin comprises cation exchange resin beads; the anion exchange resin comprises anion exchange resin beads; each of the cation exchange resin beads and the anion exchange resin beads is polymer-based; 10. The method of claim 9, wherein the cation exchange resin beads and the anion exchange resin beads have an average diameter in the range of 400 μm to 800 μm.

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