METHODS AND SYSTEMS FOR EXTRACTING, SOLIDIFICATION AND DEGASSING OF RADIOACTIVE ISOTOPES FROM SPENT ION EXCHANGE RESINS

Abstract

A system and methods for the extraction, solidification and degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins, the system comprising: a washing vessel for washing the spent resins; a reaction vessel for treating the washed spent resins with alkaline chemicals; and a decantation vessel for receiving the reacted solution and the suspended precipitate, thereby allowing for the removal of a supernatant from the remaining solution to form a solid form of carbonate and/or bicarbonate ions product, or salts thereof, comprising the radioactive isotope. A method for the extraction of a radioactive isotope from spent resins of a nuclear plant using alkaline chemicals is also provided. A method for the solidification and degassing of a radioactive isotope from spent resins of a nuclear plant is further provided.

Claims

1. A method for extraction of a radioactive isotope from spent resins of a nuclear plant, the method comprising the steps of: a) providing a first volume of spent resins; b) washing the spent resins in a washing vessel in a recirculating alkaline liquid of a second volume; and c) treating the washed spent resins with one or more alkaline chemicals of a given concentration in a reaction vessel for a given time and at a given temperature to obtain a process solution, wherein the process solution is recirculated through the resin washing vessel and the reaction vessel by a recirculating a means, thereby allowing the extraction of carbonate and bicarbonate ions containing the radioactive isotope.

2. The method of claim 1, wherein the radioactive isotope is C-14.

3. The method of claim 1, wherein the alkaline chemicals are selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH.sub.4OH), a monohydroxide base chemical, and a combination thereof.

4. The method of claim 1, wherein the concentration of the alkaline chemical in the solution ranges between 1 to 10% (w/w).

5. The method of claim 1, wherein the given temperature range is between 0 C. to 100 C., preferably 5 C. to 70 C., most preferably 20 C. to 50 C.

6. The method of claim 1, wherein the given time ranges between 30 to 180 min.

7. The method of claim 1, wherein a ratio of the second volume of the recirculating alkaline liquid and the first volume of the spent resin ranges from 2:1 to 7:1.

8. The method of claim 1, wherein the alkaline recirculating liquid is a dilute NaOH aqueous solution.

9. The method of claim 1, wherein after performing said method, the spent resin is further treated in a Pyrolysis Resins in Mobile Electric (PRIME) installation to reduce its volume.

10. A method for solidification of a radioactive C-14 isotope from spent resins of a nuclear plant, the method comprising the steps of: (a) providing a carbonate and/or bicarbonate ions extraction solution from the spent resins containing the radioactive isotope; (b) contacting the carbonate and/or bicarbonate ions extraction solution with a chemical selected from the group consisting of calcium hydroxide (Ca(OH).sub.2), magnesium hydroxide (Mg(OH).sub.2), barium hydroxide (Ba(OH).sub.2), any other dihydroxide containing salt, and combinations thereof in a reaction vessel to form a reacted solution, wherein the reacted solution is recirculated by a recirculating means within the reaction vessel to form a suspended precipitate; and (c) transferring the reacted solution and the suspended precipitate to a decantation vessel, wherein a supernatant is removed from the remaining solution to provide a solid form of carbonate and/or bicarbonate ions product, or salts thereof, comprising the C-14 radioactive isotope.

11. The method of claim 9, wherein the chemical is barium hydroxide (Ba(OH).sub.2).

12. The method of claim 10, wherein the solid form of carbonate and/or bicarbonate ions product, or salts thereof, is stored.

13. A method for degassing a C-14 radioactive isotope obtained from spent resins of a nuclear plant, the method comprising the steps of: (a) providing a solid form of carbonate and/or bicarbonate ions product, or salts thereof, extracted from the spent resins of a nuclear plant; (b) reacting the solid form of carbonate and/or bicarbonate ions product, or salts thereof in an acidic solution of a given concentration in a temperature-controlled chemical reactor, thereby producing a gas stream and a residual product; (c) contacting the gas stream with molecular sieves to retain said C-14 radioactive isotope, and optionally; (d) drying the residual product in a oven to produce solid rejects.

14. The method of claim 13, wherein the acidic solution comprises inorganic and/or organic acids, or a combination thereof.

15. The method of claim 14, wherein the acidic solution is selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H.sub.2SO.sub.4), nitric acid (HNO.sub.3), acetic acid (C.sub.2H.sub.4O.sub.2), and citric acid (C.sub.6H.sub.8O.sub.7).

16. The method of claim 14, wherein the concentration of the acid in the acidic solution ranges from 10% (w/w) to 90% (w/w).

17. A system for extraction, solidification and degasification of radioactive from spent ion exchange resins, the system comprising: a) a washing vessel for washing the spent resins in an alkaline solution; b) a reaction vessel for treating the washed spent resins with alkaline chemicals of a given concentration, for a given time and at a given temperature to obtain a process solution, wherein the process solution is recirculated through the resin washing vessel and the reaction vessel by a first recirculating a means, thereby allowing the extraction of carbonate and/or bicarbonate ions containing the radioactive isotope, and whereby the extracted carbonate and/or bicarbonate ions containing the radioactive isotope is reacted with a chemical of a given concentration in a reaction vessel to form a reacted solution, wherein the reacted solution is recirculated by a second recirculating means within the reaction vessel to form a suspended precipitate; and c) a decantation vessel for receiving the reacted solution and the suspended precipitate, thereby allowing for the removal of a supernatant from the remaining solution to form a solid form of carbonate and/or bicarbonate ions product, or salts thereof, comprising the radioactive isotope.

18. The system of claim 17 further comprising a temperature-controlled chemical reactor for reacting the solid form of carbonate and/or bicarbonate ions product, or salts thereof in an acidic solution of a given concentration in, thereby producing a gas stream and a residual product, and further comprising molecular sieves adapted to capture the radioactive isotope whereby the gas stream is contacted with the molecular sieves.

19. The system of claim 18, further comprising a Pyrolysis Resins in Mobile Electric (PRIME) installation for treating the residual product to reduce its volume.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0020] In order for the invention to be readily understood, embodiments of the invention are illustrated by way of example in the accompanying figures.

[0021] FIG. 1 schematically shows a flow chart of the overall system for the extraction, solidification and degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins.

[0022] FIG. 2 schematically shows a flow chart of the overall system and method for the extraction of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins in alkaline conditions.

[0023] FIG. 3 schematically shows a flow chart of the overall system and method for the solidification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins.

[0024] FIG. 4 schematically shows a flow chart of the overall system and method for the degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins.

[0025] FIG. 5 schematically shows another flow chart of the overall system and method for the degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins.

[0026] Further details of the invention and its advantages will be apparent from the detailed description included below.

DETAILED DESCRIPTION OF EMBODIMENTS

[0027] In the following description of the embodiments, references to the accompanying figures are illustrations of one or more examples by which the invention may be practised. It will be understood that other embodiments may be made without departing from the scope of the invention disclosed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs.

[0028] In a most general sense, the invention provides a system and method system and method for the extraction, solidification and degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins in alkaline conditions.

[0029] In the context of the present specification, the word about when used in relation to numerical designations or ranges means the exact numbers plus or minus experimental measurement errors and plus or minus 10 percent of the exact numbers.

[0030] Moreover, all statements herein reciting principles, aspects, and implementations of the present technology, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof, whether they are currently known or developed in the future. Thus, for example, it will be appreciated by those skilled in the art that any block diagrams or illustrations represent conceptual views of the principles of the present technology. Similarly, it will be appreciated that any diagrams, flowcharts, and the like represent various processes which may be substantially represented in computer-readable media and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0031] Implementations of the present technology each have at least one of the above-mentioned objects and/or aspects, but do not necessarily have all of them. It should be understood that some aspects of the present technology that have resulted from attempting to attain the above-mentioned object may not satisfy this object and/or may satisfy other objects not specifically recited herein.

[0032] Additional and/or alternative features, aspects and advantages of implementations of the present technology will become apparent from the following description, the accompanying drawings and the appended claims.

[0033] Referring now to FIGS. 1-3, in embodiments of the present invention, there is provided a system for extraction, solidification and degasification of carbon-14 isotopes (.sup.14C) and other radioactive isotopes from spent ion exchange resins, the system comprising: a washing vessel (100) for washing the spent resins (1000); a reaction vessel (200) for treating the washed spent resins with alkaline chemicals (130) of a given concentration for a given time and at a given temperature to obtain a process solution (210), wherein the process solution (210) is recirculated through the resin washing vessel (100) and the reaction vessel (200) by a recirculating a means (300a), thereby allowing the extraction of carbonate and/or bicarbonate ions containing the radioactive isotope, and whereby the extracted carbonate and/or bicarbonate ions containing the radioactive isotope are reacted with a chemical (220) of a given concentration in the reaction vessel (200) to form a reacted solution (250), wherein the reacted solution (250) is recirculated by a recirculating means (300b) within the reaction vessel (200) to form a suspended precipitate (230); and a decantation vessel (400) for receiving the reacted solution (250) and the suspended precipitate (230), thereby allowing for the removal of a supernatant (420) from the remaining solution (410) to yield a solid form of carbonate and/or bicarbonate ions product, or salts thereof (500), comprising the radioactive isotope.

[0034] Referring to FIGS. 1-4, in embodiments, the system may comprise a temperature-controlled chemical reactor (700) for reacting (520) the solid form of carbonate and/or bicarbonate ions product, or salts thereof (500) in an acidic solution (600) of a given concentration in, thereby producing a gas stream (710) and a residual product (720), wherein the gas stream (710) is contacted with molecular sieves (810a, 810b) in a container (800) and/or the residual product (720) is dried in a oven to produce solid rejects (900).

[0035] In embodiments, as illustrated in FIG. 1, the previously described system may further comprise means for storing (530) the solid form of carbonate and/or bicarbonate ions product, or salts thereof (500).

[0036] In embodiments, as illustrated in FIG. 1, the previously described system may further comprise a Pyrolysis Resins in Mobile Electric (PRIME) (120) installation for treating the resin to reduce its volume.

[0037] Still referring to the system previously described and illustrated in FIGS. 1-4, in embodiments, there is provided a system where the radioactive isotope may be C-14.

[0038] The alkaline chemicals may be selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH.sub.4OH), a monohydroxide base chemical, and any combination thereof.

[0039] The concentration of the alkaline chemical in the solution may range between about 1 to 10% (w/w).

[0040] The given temperature may range between about 0 C. to 100 C., preferably 5 C. to 70 C., most preferably 20 C. to 50 C.

[0041] The given time may range between about 30 to 180 min.

[0042] The ratio of the second volume of the recirculating liquid and the first volume of the spent resin may range from about 2:1 to 7:1.

[0043] In embodiments, the alkaline chemicals may be selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH.sub.4OH), a monohydroxide base chemical, and any combination thereof.

[0044] The concentration of the alkaline chemical in the solution may range between about 1 to 10% (w/w).

[0045] Referring now to FIG. 2, in embodiments of the present invention, there is provided a method for the extraction of a radioactive isotope from spent resins of a nuclear plant, the method comprising the steps of: providing a first volume of spent resins (1000); washing the spent resins in a washing vessel (100) in a recirculating liquid of a second volume; and treating the washed spent resins with alkaline chemicals (130) of a given concentration in a reaction vessel (200) for a given time and at a given temperature to obtain a process solution (210), wherein the process solution (210) is recirculated through the resin washing vessel (100) and the reaction vessel (200) by a recirculating a means (300a), thereby allowing the extraction of carbonate and bicarbonate ions containing the radioactive isotope.

[0046] In embodiments, as illustrated in FIG. 2, the radioactive isotope previously described in the method may be selected from the group consisting of C-14.

[0047] In embodiments, the alkaline chemicals may be selected from the group consisting of sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH.sub.4OH), a monohydroxide base chemical, and any combination thereof.

[0048] The concentration of the alkaline chemical in the solution may range between about 1 and 10% (w/w).

[0049] The given temperature may range between about 0 C. to 100 C., preferably 5 C. to 70 C., most preferably 20 C. to 50 C.

[0050] The given time may range between about 30 to 180 min.

[0051] In embodiments, as illustrated in FIG. 2, the previously described method may have a ratio of the second volume of the recirculating liquid and the first volume of the spent resin that ranges from 2:1 to 7:1.

[0052] The resin may optionally be treated in a Pyrolysis Resins in Mobile Electric (PRIME) (120) installation to reduce its volume.

[0053] Referring now to FIG. 3, in embodiments of the present invention, there is provided a method for solidification of a radioactive isotope from spent resins of a nuclear plant, the method comprising the steps of: providing a carbonate and/or bicarbonate ions extraction solution (240) from the spent resins containing the radioactive isotope; contacting the carbonate and/or bicarbonate ions extraction solution with a chemical (220) of a given concentration in a reaction vessel (200) to form a reacted solution (250), wherein the reacted solution (250) is recirculated by a recirculating means (300c) within the reaction vessel (200) to form a suspended precipitate (230); and transferring the reacted solution (250) and the suspended precipitate (230) to a decantation vessel (400), wherein a supernatant (420) is removed from the remaining solution (410) to form a solid form of carbonate and/or bicarbonate ions product, or salts thereof (500), comprising the radioactive isotope.

[0054] Still referring to the method previously described and represented in FIG. 3, in embodiments, the chemical may be selected from the group consisting of calcium hydroxide (Ca(OH).sub.2), magnesium hydroxide (Mg(OH).sub.2), barium hydroxide (Ba(OH).sub.2), any other dihydroxide containing salt, and a combination thereof.

[0055] The chemical may be barium hydroxide (Ba(OH).sub.2).

[0056] Still referring to FIG. 3, in embodiment, the given concentration of the chemical (220) is dependent on the concentration of the carbonate and/or bicarbonate ions extraction solution (240).

[0057] The radioactive isotope may be C-14.

[0058] The solid form of carbonate and/or bicarbonate ions product, or salts thereof (500) may be stored (510) using storing means (530).

[0059] In embodiments, and now referring to FIG. 4, there is provided a method for the degassing of a radioactive isotope from spent resins of a nuclear plant, the method comprising the steps of: providing a solid form of carbonate and/or bicarbonate ions product, or salts thereof (500), extracted from the spent resins of a nuclear plant; reacting (520) the solid form of carbonate and/or bicarbonate ions product, or salts thereof (500) in an acidic solution (600) of a given concentration in a temperature-controlled chemical reactor (700), thereby producing a gas stream (710) and a residual product (720); and contacting the gas stream (710) with molecular sieves (810a, 810b) in a desiccant (800).

[0060] Still referring to the method previously described and represented in FIG. 4, in embodiments, the method may further comprise the step of drying the residual product (720) in an oven to produce solid rejects (900).

[0061] In embodiments, the acidic solution may comprise inorganic and/or organic acids, or a combination thereof.

[0062] The acidic solution (600) may be selected from the group consisting of hydrochloric acid (HCl), sulfuric acid (H.sub.2SO.sub.4), nitric acid (HNO.sub.3), acetic acid (C.sub.2H.sub.4O.sub.2), citric acid (C.sub.6H.sub.8O.sub.7).

[0063] The concentration of the acid in the acidic solution (600) may range from about 10% (w/w) to 90% (w/w), and it may be further adjusted depending on the acid used.

[0064] The radioactive isotope is C-14.

[0065] Those skilled in the art will recognize, or be able to ascertain, using no more than routine experimentation, numerous equivalents to the specific procedures, embodiments, claims, and examples described herein. Such equivalents are considered to be within the scope of this invention and covered by the claims appended hereto.