WO2018187194A1 - Système de détermination de masse de sel fondu, et procédés associés - Google Patents

Système de détermination de masse de sel fondu, et procédés associés Download PDF

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Publication number
WO2018187194A1
WO2018187194A1 PCT/US2018/025633 US2018025633W WO2018187194A1 WO 2018187194 A1 WO2018187194 A1 WO 2018187194A1 US 2018025633 W US2018025633 W US 2018025633W WO 2018187194 A1 WO2018187194 A1 WO 2018187194A1
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Prior art keywords
molten salt
mass
activity
sample
radioactive isotope
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PCT/US2018/025633
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English (en)
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Shelly X. Li
Jeffrey D. Sanders
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Battelle Energy Alliance, Llc
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Publication of WO2018187194A1 publication Critical patent/WO2018187194A1/fr

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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
    • G21C19/42—Reprocessing of irradiated fuel
    • G21C19/50—Reprocessing of irradiated fuel of irradiated fluid fuel, e.g. regeneration of fuels while the reactor is in operation
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21H—OBTAINING ENERGY FROM RADIOACTIVE SOURCES; APPLICATIONS OF RADIATION FROM RADIOACTIVE SOURCES, NOT OTHERWISE PROVIDED FOR; UTILISING COSMIC RADIATION
    • G21H5/00—Applications of radiation from radioactive sources or arrangements therefor, not otherwise provided for 
    • G21H5/02—Applications of radiation from radioactive sources or arrangements therefor, not otherwise provided for  as tracers
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F22/00—Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C1/00—Reactor types
    • G21C1/04—Thermal reactors ; Epithermal reactors
    • G21C1/06—Heterogeneous reactors, i.e. in which fuel and moderator are separated
    • G21C1/22—Heterogeneous reactors, i.e. in which fuel and moderator are separated using liquid or gaseous fuel
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C3/00—Reactor fuel elements and their assemblies; Selection of substances for use as reactor fuel elements
    • G21C3/42—Selection of substances for use as reactor fuel
    • G21C3/44—Fluid or fluent reactor fuel
    • G21C3/54—Fused salt, oxide or hydroxide compositions
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • Embodiments of the disclosure relate to methods for determining the mass of a material. More specifically, embodiments of the disclosure relate to methods for determining the mass of a liquid, such as a molten salt in a container with a non- geometrically shaped cavity and unknown volume.
  • Electrochemical recycling is a group of technologies that has been developed to separate actinide components from spent nuclear fuel.
  • An integral part of the separation process involves electrorefining the spent nuclear fuel in a high temperature molten salt containing the spent nuclear fuel.
  • Electrorefining includes refining a metal in an electrochemical cell containing the molten salt, wherein the impure metal is used as the anode and the refined metal is deposited on the cathode.
  • the nature of the electrochemical recycling process requires the total concentration of uranium and transuranic isotopes in the molten salt to be up to 9.0 wt%.
  • the transuranic isotopes are mainly plutonium with minor quantities of americium, neptunium, and curium.
  • Measuring the molten salt mass in an electrorefiner is a critical step to safeguard electrochemical recycling plants through nuclear material accountancy.
  • the inventory of transuranic isotopes in the molten salt is an important key measurement point for the International Atomic Energy Agency to conduct nuclear material accountancy for its verification activities essential for international safeguards. Accounting for the nuclear material inventory requires knowing the concentrations of nuclear materials in the molten salt and the mass of the molten salt. A similar mandate by the International Atomic Energy Agency or by others would apply to molten salt nuclear reactors when they become commercially available.
  • determining the molten salt mass in an electrochemical cell includes measuring the molten salt liquid level, defining the salt volume through the measured liquid level and a pre-established volume calibration curve for the particular electrochemical cell and associated components thereof, and estimating salt density to calculate the salt mass.
  • this method results in a high degree of uncertainty in the salt mass determination because of limitations, including challenges in determining the volume of a container with a non-geometrically shaped cavity such as the electrochemical cell, which also usually includes numerous components (e.g., electrodes, sensors, mixers, scrapers, etc.) of unknown volume and non-geometric shapes within the container as well.
  • volume calibration curve using measurements at room temperature, which would not reflect, for example, the thermal expansion that would occur at the high temperatures at which an electrorefiner operates (for example, 500°C).
  • the salt density varies as the concentrations of actinides and fission products dissolved in the salt changes.
  • the temperature of the molten salt increases a difficulty of making such measurements.
  • An embodiment of the invention relates to a method for determining molten salt mass in a container with a non-geometrically shaped cavity using a radioactive tracer dilution technique.
  • the method includes the acts (e.g., steps) of adding a known amount of a radioactive isotope tracer with known activity into the molten salt, mixing the radioactive isotope tracer with the molten salt until homogeneous, obtaining a sample of the resulting mixture, measuring the activity of the sample, and calculating the molten salt mass using radioactive isotope tracer dilution analysis.
  • An embodiment of the invention may also include using 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, or 168 Tm as the radioisotope in the radioactive isotope tracer.
  • the compound containing the radioactive isotope tracer may be in a salt such as the fluorides, chlorides, bromides, iodides, and combinations thereof depending on the physical and chemical properties of the molten salt to be measured.
  • the radioactive isotope tracer may be selected from the group consisting of a fluoride salt, a chloride salt, a bromide salt, an iodide salt, and combinations thereof.
  • C0CI2, KBr, NaCl, RbCl, NaF, NaBr, Nal, or TmCh may be used.
  • An embodiment of the invention may also include using gamma spectrometry to measure the activity.
  • the gamma-ray spectrometry may be performed using a high purity germanium (HPGe) detector.
  • HPGe high purity germanium
  • Other methods may be utilized to measure the activity using chemical analysis, spectroscopy, or another means.
  • Another embodiment of the invention may also include adding a known amount of a radioactive isotope tracer with known activity into a liquid into which another material has been dissolved, mixing the radioactive isotope tracer with the liquid until homogeneous to form a mixture, obtaining a sample of the resulting mixture, measuring the activity of the sample, and calculating the mass of the mixture using radioactive isotope tracer dilution analysis.
  • a method for determining a mass of a molten salt in a container comprises adding an amount of a radioactive isotope tracer with known activity and known mass into a molten salt in a container, mixing the radioactive isotope tracer with the molten salt to form a mixture, obtaining a sample of the mixture, weighing the sample, measuring the activity of the sample using gamma spectrometry, and calculating the molten salt mass based, at least in part, on the weight of the sample and the activity of the sample.
  • a system for determining a mass of a molten salt comprises an electrochemical cell comprising a molten salt, one or more spent nuclear fuels in the electrochemical cell, and a radioisotope tracer disposed substantially uniformly throughout the molten salt.
  • FIG. 1 is a simplified cross-sectional view of a system for electrorefining spent nuclear fuel or another material, in accordance with embodiments of the disclosure
  • FIG. 2 is a simplified schematic of a method of determining a mass of a molten salt in a container, in accordance with embodiments of the disclosure
  • FIG. 3 is a gamma-ray emission spectrum of a sample containing 22 Na and 154 Eu;
  • FIG. 4A and FIG. 4B are photographs of the geometry for a GC5019 high-purity germanium gamma-ray detector;
  • FIG. 5 is a spectrum from of a calibration measurement for an HPGe detector
  • FIG. 6 is a spectrum from a sample count, in accordance with an embodiment of the disclosure
  • FIG. 7 is a plot of a measured 22 Na activity against the mass of a salt using a first detector.
  • FIG. 8 is a plot of a measured 22 Na activity against the mass of a salt using a second detector.
  • radioactive isotope tracer dilution analysis is applied to determine the mass of a high temperature molten salt laden with nuclear materials and fission products.
  • the mass of the molten salt can provide information for nuclear material accountancy for the purpose of physical inventory verification (PIV) for safeguarding nuclear materials dissolved in the molten salt.
  • radioactive isotope tracer dilution analysis may be performed to determine the mass of molten salt within a container, such as a container with a non-geometrically shaped cavity.
  • the temperature of the molten salt does not influence the determination.
  • the determination of the mass of molten salt in the container is independent of the temperature of the molten salt.
  • a method for determining the mass of a molten salt using radioactive isotope tracing and radioactive isotope dilution analysis is disclosed.
  • radioisotope tracer As used herein, the terms “radioisotope tracer” and “radioactive isotope tracer” are used interchangeably.
  • a container may refer to a structure defining a volume configured to retain one or more materials.
  • a container may include irregular shapes and may not exhibit a substantially uniform cross-sectional area along different portions thereof.
  • FIG. 1 a simplified cross-sectional view of a system 100 for electrorefining spent nuclear fuel or another material is shown.
  • the system 100 includes an electrochemical cell 102 including a molten salt 104, such as a molten salt electrolyte.
  • the electrochemical cell 102 may be supported on a support structure 120.
  • the electrochemical cell 102 may exhibit a non-geometrically shaped cavity.
  • FIG. 1 illustrates the electrochemical cell 102 having a particular geometry, the disclosure is not so limited.
  • a cross-sectional shape of the electrochemical cell 102 may not be the same along a length thereof.
  • the electrochemical cell 102 may have a shape other than a right cylinder.
  • the electrochemical cell 102 may have a shape other than a right cylinder.
  • electrochemical cell 102 may include various components and sensors (e.g., electrodes (anode, cathode, etc.), stirring rod, etc.) that may consume a volume within the electrochemical cell 102 .
  • sensors e.g., electrodes (anode, cathode, etc.), stirring rod, etc.
  • electrochemical cell 102 The presence of such components increases a difficulty of determining a volume, and hence, a mass of the molten salt 104 in the electrochemical cell 102.
  • the molten salt 104 may include lithium chloride (LiCl), lithium oxide (L12O), a mixture of lithium chloride and lithium oxide, sodium chloride (NaCl), calcium chloride (CaCk), calcium oxide (CaO), a mixture of calcium chloride and calcium oxide, lithium bromide (LiBr), potassium bromide (KBr), cesium bromide (CsBr), calcium bromide (CaBrc), potassium bromide (KBr), strontium chloride (SrCh), strontium bromide (SrBrc), a eutectic salt of lithium chloride and potassium chloride (e.g., LiCl-KCl having about 56 weight percent KC1), uranium tetrafluoride (UF4), uranium tetrafluoride and thorium tetrafluoride (UF4 and ThF4), another molten salt, and combinations thereof.
  • LiCl-KCl having about 56 weight percent KC1
  • the uranium tetrafluoride may be dissolved in at least one of molten lithium fluoride (LiF), molten beryllium fluoride (BeF2), and molten zirconium fluoride (ZrF4).
  • the molten salt 104 may comprise uranium tetrafluoride dissolved in each of molten lithium fluoride, beryllium fluoride, and zirconium fluoride (i.e., LiF-BeF2-ZrF4-UF4).
  • the molten salt 104 may further include at least one of lithium fluoride and beryllium fluoride.
  • the molten salt may comprise uranium tetrafluoride, thorium tetrafluoride, lithium fluoride, and beryllium fluoride (i.e., LiF-BeF2-ThF4-UF4).
  • the disclosure is not so limited and the molten salt 104 may comprise one or more other materials.
  • a cathode 106 and an anode 108 may disposed in the molten salt 104.
  • One or more heating elements 110 may be disposed around at least a portion of the electrochemical cell 102 and may be configured to maintain a desired temperature of the molten salt 104.
  • a stirring assembly 112 may be disposed in the molten salt 104 and may be configured to mix the molten salt 104 such that the molten salt 104 exhibits a substantially uniform composition throughout a volume thereof.
  • a heat shield reflector 118 such as a material comprising a thermally insulative material, may be disposed around at least a portion of the electrochemical cell 102 to insulate the electrochemical cell 102 from an external environment.
  • the electrochemical cell 102 may include one or more scrapers configured to scrape materials accumulated at sides, a bottom surface, or both of the electrochemical cell 102.
  • a basket 116 configured to carry one or more nuclear fuels may be disposed around at least a portion of the anode 108.
  • the basket 116 is integral with the anode 108.
  • the basket 116 may include one or more spent nuclear fuels.
  • the basket 116 may include spent uranium dioxide, spent uranium oxide (e.g., U3O8), uranium silicide (U3S12), uranium carbide (UC), uranium carbide oxide (UCO), uranium- molybdenum fuels (U-Mo) and alloys thereof, uranium-beryllium (UBe x ) and oxides thereof (e.g., BeO-UC ), another nuclear fuel, or combinations thereof.
  • the nuclear fuel may dissolve in the molten salt 104.
  • one or both of uranium tetrafluoride and thorium tetrafluoride may dissolve in a fluoride molten salt, the fluoride molten salt comprising one or more of lithium fluoride, beryllium fluoride, zirconium fluoride, or another fluoride, as described above.
  • the molten salt 104 may have an unknown mass M sa it in the electrochemical cell 102 (also referred to herein as "an electrorefiner"), which is an example of a container with a non-geometrically shaped cavity.
  • a mass of the molten salt 104 may be determined, independent of the components contained within the electrochemical cell 102 and even if the electrochemical cell 102 exhibits an irregular shape.
  • a radioisotope tracer with a known mass, M r , and activity, A r , may be added to the molten salt 104.
  • the sample is weighed with weight Ms.
  • the activity of the sample, As is measured using, for example, an HPGe detector.
  • an electrorefiner container e.g., vessel, such as the electrochemical cell 102 where the mass of molten salt 104 is generally greater than 10 kg
  • the mass of the radioisotope tracer, Mr can be ignored.
  • Application of the radioactive tracer dilution technique results in the equation for the mass M sa it of the molten salt.
  • a known mass (Mr) of a radioactive isotope tracer with known or measurable activity (A r ) is added to a liquid, such as the molten salt 104, in which the mass of the liquid is to be determined.
  • the liquid and radioactive isotope tracer are mixed until homogeneous to form a mixture.
  • a sample, such as a grab sample, of the liquid mixed with radioactive isotope tracer is obtained.
  • the sample is weighed (1 ⁇ 2), and the activity of the sample (A s ) is measured.
  • the mass of the liquid M such as the molten salt 104, may be determined through the following equations:
  • the mass of a material within a container may be determined by selecting a radioisotope tracer to exhibit an activity at a unique energy relative to other components of the material within the container. For example, by multiplying the mass of the sample by the ratio of the activity of the radioisotope tracer to the activity of the sample according to Equation (3) above, the unknown mass of the material within the container may be determined.
  • a method 200 of determining a mass of a molten salt in a container such as an electrochemical cell used for electrorefining spent nuclear fuel.
  • the method 200 includes act 202 including adding a radioisotope tracer having a known mass and a known activity to a container including a material; act 204 including mixing the radioisotope tracer with the material in the container; act 206 including obtaining a mixed sample from the container and measuring the mass and activity of the sample; and act 208 including determining the mass of the material in the container based, at least in part, on the mass and activity of the sample.
  • Act 202 includes adding a radioisotope tracer having a known mass and a known activity to a container including a material.
  • the container may comprise, for example, an electrochemical cell (e.g., the electrochemical cell 102 (FIG. 1)) used in an electrorefining process.
  • the material may include a liquid, such as a molten salt (e.g., the molten salt 104 (FIG. 1)).
  • molten salt e.g., the molten salt 104 (FIG. 1)
  • Spent nuclear fuel from nuclear power plants contains numerous radioactive isotopes, and many of the radioactive isotopes in the spent nuclear fuel can be found in the electrorefiner salt (e.g., the molten salt 104) during the electrochemical recycling process.
  • the radioactive isotope tracer in some embodiments, may be different from the constituents of spent nuclear fuels, and the activity of the radioisotope tracer may be measurable directly with better than 1% accuracy.
  • Radioactive isotopes that can be used include 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, and 168 Tm.
  • radioactive isotopes may include 7 Be, 2 P, 5 P, 5 S, 45 Ca, 48 V, 49 V, 54 Mn, 55 Fe, 59 Fe, 57 Co, 65 Zn, 68 Ge, 75 Se, 8 Rb, 85 Sr, 88 Zr, 88 Y, 109 Cd, 113 Sn, 170 Tm, 171 Tm, 173 Lu, 174 Lu, 172 Hf, 175 Hf, 179 Ta, 181 W, 188 W, 182 Ta, 204 T1, and combinations thereof.
  • the radioactive isotopes may be identified and quantified by gamma-ray spectroscopy to determine activity.
  • the radioactive isotope comprises 22 Na.
  • radioactive isotopes may be utilized as the tracer.
  • the radioactive isotope tracer may be selected based on, among other things, a chemical compatibility of the radioactive isotope tracer with the molten salt 104, the activity of the radioactive isotope tracer, and the half- life thereof.
  • the compounds from which these isotopes could be obtained include salts such as the fluorides, chlorides, bromides, and iodides thereof, depending on the physical and chemical properties of the molten salt to be measured. For example, C0CI2, CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCh may be used.
  • the radioactive isotope tracer comprises at least one of 60 Co or 22 Na.
  • the radioactive isotope tracer may be selected to be chemically compatible with the electrorefiner salt (e.g., the molten salt 104 (FIG. 1)).
  • the electrorefiner salt e.g., the molten salt 104 (FIG. 1)
  • a tracer of the isotope 22 Na in the form of NaCl may be compatible with a LiCl-KCl eutectic based salt.
  • Cobalt belongs to the noble metal group in the electrochemical recycling process. Based on the thermodynamics of Co 2+ , Co 2+ in the salt phase can be reduced to cobalt metal by an active metal such as uranium. However, 60 Co may be used as a tracer in some embodiments, such as where reduction of Co 2+ is not a concern.
  • the amount of the radioactive isotope tracer added to the material in the container may be related to the quantity of molten salt in the vessel. For example, less than 1 ⁇ of either 60 Co or 22 Na is estimated to be needed to be added to have better than 1% accuracy from a less than 1 gram sample of molten salt. For electrorefiners with larger containers and molten salt content in the tens to hundreds of kilograms, larger quantities of the radioactive tracer may be added to the electrorefiner container to ensure homogeneity of the distribution of the radioactive isotope tracer throughout the electrorefiner container.
  • between about 0.10 ⁇ and about 2.0 ⁇ 3 ⁇ 4 such as between about 0.10 ⁇ Ci and about 0.25 ⁇ , between about 0.25 ⁇ and about 0.50 ⁇ , between about 0.50 ⁇ and about 0.75 ⁇ 3 ⁇ 4 between about 0.75 ⁇ Ci and about 1.0 ⁇ 3 ⁇ 4 between about 1.0 ⁇ Ci and about 1.5 ⁇ , or between about 1.5 ⁇ Ci and about 2.0 ⁇ of the radioactive isotope tracer may be added to the container for every estimated about 1.0 gram of the molten salt.
  • the disclosure is not so limited and a different amount of the radioactive isotope tracer may be added to the container for every particular amount of the molten salt.
  • the mass of the radioactive isotope tracer may be selected to be less than about 1.0 weight percent of an estimate mass of the molten salt 104, such as less than about 0.5 weight percent, less than about 0.1 weight percent, less than about 0.01 weight percent, less than about 0.001 weight percent, or even less than about 0.0001 weight percent a mass of the molten salt 104.
  • the weight percent of the radioactive isotope tracer may be less than about 1.0 ppm. The amount of the radioactive isotope tracer added to the container may be selected based on the composition of the molten salt 104 and a desired accuracy of the activity determination.
  • Act 204 may include mixing the radioisotope tracer with material in the container.
  • the container may include, a mixer, such as the stirring assembly 1 12 (FIG. 1), configured to substantially uniformly disperse the radioisotope tracer within the material in the container.
  • act 206 may include obtaining a mixed sample from the container and measuring the mass and activity of the sample.
  • Act 208 may include determining the mass of the material in the container based, at least in part, on the mass and activity of the sample.
  • the mass of the material in the container may be determined according to Equation (2) or Equation (3) above, based on the activity of the radioisotope tracer (A r ), the mass of the radioactive tracer (Mr), the measured mass of the sample (M s ), and the measured activity of the sample (A s ).
  • the mass of the material in the container is determined without knowledge of the mass of the radioactive tracer. Accordingly, the mass of the material in the container may be determined without a knowledge of the geometry of the container.
  • the activity of the sample may be determined with a high-purity germanium (HPGe) detector with a gamma-ray spectroscopy system.
  • HPGe high-purity germanium
  • the activity of the radioactive isotope tracer exhibits a peak energy at a different wavelength than components of the molten salt 104.
  • the molten salt 104 may include one or more radioactive isotopes exhibiting an energy peak at one or more energies in the gamma-ray spectrum as the selected radioisotope tracer.
  • act 208 may include subtracting the signal (e.g., the energy counts) in the spectrum due to the presence of the one or more radioactive isotopes in the molten salt 104 from the signal (e.g., the energy counts) due to the radioisotope tracer.
  • the molten salt 104 may include 154 Eu, which exhibits a gamma ray emission at 1,274.46 keV.
  • a gamma-ray emission spectrum of a sample containing 22 Na and 154 Eu is illustrated in FIG. 3.
  • 154 Eu includes a peak count at a gamma ray emission wavelength of about 1,274.46 keV, which may interfere with the emission energy of about 1,274.54 keV emitted from 22 Na.
  • the signal of the 154 Eu may interfere with the signal of the 22 Na tracer.
  • the contribution of the 154 Eu to the 22 Na peak at 1,274.54 keV may be subtracted from the signal measured at 1,274.54 keV.
  • 154 Eu has an emission spectrum including several emission energies (e.g., 123.1 keV, 247.9 keV, 591.8 keV, 723.3 keV, 756.8 keV, 873.2 keV, 996.2 keV, 1,004.7 keV, and 1,274.46 keV).
  • the contribution of the 154 Eu to the gamma ray emission peak at 1,274.46 keV may be determined and subtracted from the measured energy at 1,274.54 keV to determine the energy contributed by the 22 Na tracer. Accordingly, in some embodiments, the spectrum may be compensated for other radioactive isotopes in the molten salt that exhibit emission energies close to the emission spectrum of the radioisotope tracer.
  • the radioactive isotope tracer may be used to determine a mass of a material without knowledge of a volume of a container in which the radioactive isotope tracer is contained and without knowledge of the density of the material.
  • the container may have an irregular shape.
  • the mass of the material may be determined independent of the temperature of the material.
  • the method may be used to determine an unknown mass greater than about 10 kg, greater than about 100 kg, greater than about 500 kg, greater than about 1,000 kg, or even greater than about 2,000 kg.
  • FIG. 1 and FIG. 2 have been described as including determining a mass of a molten salt in an electrochemical cell, the disclosure is not so limited.
  • another embodiment of the invention may also include adding a known amount of a radioactive isotope tracer with known activity into a liquid into which another material has been dissolved, mixing the radioactive isotope tracer with the liquid, obtaining a sample of the resulting mixture, measuring the activity of the sample, and calculating the mass of the mixture using radioactive isotope tracer dilution analysis.
  • FIG. 1 and FIG. 2 have been described as including determining a mass of a molten salt in a container having an irregular shape, the disclosure is not so limited. In other embodiments, the method may be used to determine the mass of a material in a container having a shape such as a cylindrical shape, a spherical shape, or any other shape.
  • Samples of salts with 22 Na activity were prepared and measurements of mass and activity in the salt samples were obtained using a gamma-ray spectroscopy system.
  • radioisotope 22 Na (an amount having an activity of 10.59 ⁇ ) was purchased in the form of a 22 NaCl aquarium solution, which was sealed in a glass ampule. Upon breaking the ampule about 2 mL of the solution was transferred to an empty crucible.
  • the crucible was put into an oven that had been preheated to 150°C.
  • the crucible was heated in the oven for 20 minutes and then cooled for 20 minutes before being removed from the oven. After being removed from the oven, the liquid on the bottom of the crucible was no longer visible, and the source material (i.e., the 22 Na) appeared as a thin reflective layer on the bottom of the crucible.
  • the crucible was then immediately covered with three layers of plastic food wrap (PVC film). Following these steps, a radiation smear survey of the crucible found no contamination of the laboratory equipment (such as glassware) with radioisotopes.
  • the total activity of 22 Na deposited in the crucible which is the total initial activity used for this proof-of-the-concept experiment, was measured using spectroscopy. The activity measured was about 5.49 ⁇ of 22 Na.
  • LiCl-KCl (58 mole % LiCl) was prepared for use.
  • This LiCl-KCl sample was loaded within Crucible 1 for a total crucible weight of 141.4020 ⁇ 0.0001 grams.
  • Crucible 1 was then loaded into a furnace, and the furnace was set for 550°C. It took 30 minutes for the furnace to stabilize from room temperature to 550°C. At 2 hours, 4.5 hours, and 14.25 hours after initially tuming on the fumace, the salt sample was stirred using a tungsten rod for approximately 1 minute per stirring. The furnace throughout the operation was ⁇ 5°C of the set point.
  • Sources of error and possible solutions to the error include the inability to remove the entire salt sample from Crucible 1 and the temperature of equilibration, as described herein.
  • one source of error of the experimental procedure was an inability to easily remove the salt sample from Crucible 1 after the furnace had cooled.
  • the method used was to slowly hammer small pieces of salt to be removed. This hammering style of removal led to a larger mass loss (-0.5716 g) of the salt than desired.
  • the mass loss came from the accumulation of small pieces occasionally bouncing out of the crucible upon impact of the pick. However, this loss did not affect the measured mass versus its corresponding activity.
  • Another solution would be to change the crucible from alumina to a glassy carbon crucible.
  • Previous testing in the lab showed that removing an intact salt sample from a glassy carbon crucible is nearly always successful, while removing an intact salt sample from an alumina crucible is nearly impossible. By removing an intact salt sample from the crucible, the mass loss from breaking the salt into pieces could have been reduced.
  • LiCl-KCl-NaCl would reach equilibrium with the LiCl-KCl eutectic. While phase diagrams for LiCl- KC1 and KCl-NaCl are plentiful, finding the ternary of LiCl-KCl-NaCl was difficult.
  • the equilibration temperature for the mixing of the LiCl-KCl-NaCl was chosen to be that which was representative of an electrorefiner.
  • the analytical balance had an uncertainty of 0.0001 grams (except for the initial measurement of the LiCl-KCl which was 0.00001 grams).
  • the three crucibles with the prepared samples were sealed, and an empty crucible was used for calibration-standard measurements. Measurements of the three samples were made using two different detectors in the gamma-ray spectroscopy system.
  • a gamma-ray spectroscopy system typically consists of an HPGe semiconductor detector, a pre-amplifier, an amplifier, a high-voltage power supply, a multi-channel analyzer (MCA), and a computer-based acquisition and analysis system. In modem systems, many of these components are often combined into integrated units.
  • Gamma rays emitted from a radioactive source that are absorbed in the HPGe detector produce electrical pulses.
  • the pulse amplitude is proportional to the energy deposited in the detector, which allows for measurement of gamma ray energies.
  • the MCA sorts these pulses by amplitude, and computer software displays a plot of the number of pulses received at each pulse amplitude, corresponding to the energy (e.g., in keV) of the radioactive source.
  • Such a plot is called a spectrum because it shows the spectrum of energies emitted by the source. Comparison of the peaks found in a spectrum against a library of known radionuclide energies and abundances allows identification of the radioactive components of a sample.
  • the activity of those radionuclides can be quantified.
  • the library of known radionuclide energies and abundances e.g., intensity at each energy
  • an emission energy e.g., a gamma ray energy
  • Data acquisition and control, as well as quantitative analysis of identified radionuclide activity, is performed by a software package (e.g., the software package Genie 2000 from Canberra Industries).
  • the software provides for spectrum acquisition, storage, isotope identification, and activity quantification, as well as detector system energy and efficiency calibration. All files associated with this program (spectra, calibration files, etc.) are stored on the host computer and duplicated to a backup server.
  • a gamma-ray spectroscopy system may include the computer used for analysis and display as well as the Lynx MCA, a detector shield that minimizes counts from background radiation, and a vacuum dewar filled with liquid nitrogen for keeping the HPGe detector at its operating temperature.
  • Calibration of a gamma-ray spectrometer involves placing a traceable source, often with emissions at multiple gamma-ray energies, in a repeatable position relative to the detector and acquiring a spectrum. Using the measured spectrum in conjunction with the source activity and date from the source calibration certificate (as well as the half-life of the source, among other things), the analysis software then computes the efficiency of the detector as a function of energy for the source in that position, typically using log-log interpolation between calibration peak energies to create an efficiency curve as a function of energy.
  • the first detector is a Canberra GC5019 HPGe, which has an efficiency of 50% relative to a standard 3"x3" Nal detector at 1332 keV, and has a full width at half max of 1.9 keV for peaks measured at 1332 keV.
  • the second detector is a Canberra GC1419 HPGe, which has an efficiency of 14% relative to a standard 3"x3" Nal detector at 1332 keV, and has a full width at half max of 1.9 keV for peaks measured at 1332 keV.
  • 60 Co was chosen because of the energy of its emitted gamma rays at 1173 keV and 1332 keV, which bracket the energy of 22 Na at 1275 keV (1,274.54 keV).
  • the calibration source has a stated 2-sigma activity uncertainty (95% confidence) of 2%.
  • the calibration source approximates a point source and the salt samples were distributed sources approximating a disk with a diameter of about 1.25 inches (3.175 cm)
  • a geometry was chosen that placed the sources to be measured at a great enough distance from the detector that the difference in geometry between the calibration source and salt samples is negligible for gamma-ray spectroscopy system measurements.
  • the minimum source-to-detector distance should be at least five times greater than the largest extent of the source, which in this case is the diameter of 1.25 inches
  • FIGS. 4A and 4B show the chosen geometry for detector GC5019.
  • FIG. 4A shows the detector shield with the measurement platform extending above it
  • FIG. 4B shows a top-down view of the crucible above the detector.
  • the calibrations can be used in conjunction with the measured spectra for the salt samples to quantify 22 Na activity. Calculations of sample activity take into account the efficiency of the detector system at the energy of interest, the gamma-ray emission probability for the isotope/energy, and correction for radioactive decay during the count.
  • FIG. 5 shows the spectrum from the calibration measurement, in which peaks at 1173 keV and 1332 keV are seen, as is the Compton continuum at energies below the peak energies.
  • FIG. 6 shows the spectrum from one of the sample counts of one of the crucibles. In addition to the peak at 1275 keV, there is a peak at 51 1 keV, which corresponds to annihilation photons from the positrons that are also emitted from 22 Na.
  • any measurement based on radiation counting systems will have an uncertainty component proportional to the square root of the net number (continuum-subtracted) of counts recorded. This source of uncertainty can be reduced by increasing the count time but eventually reaches a point of diminishing returns. Each sample was counted long enough to ensure at least 10,000 counts in the photopeak, which corresponds to a 1 -sigma uncertainty (68% confidence) of 1 %.
  • the uncertainty in the detector efficiency is a function of the number of counts recorded when counting the calibration source for the efficiency calibration, the stated activity uncertainty in the calibration source from its certificate, and the uncertainty associated with assigning an efficiency value to the energy of the gamma ray of interest in the sample.
  • the calibration source has a stated 1-sigma activity uncertainty (68% confidence) of 1%.
  • the analysis software accounts for each of these components of uncertainty and folds them all into a final uncertainty associated with the measured activity.
  • the activity uncertainty (in ⁇ ) listed in the fourth column of each of Table II and Table III was taken directly from the software output.
  • the relative uncertainty (in %) was calculated by dividing this value by the measured activity. All uncertainties listed (absolute and relative) represent one standard deviation.
  • a least-squares fit of the data to a line through the origin yields an R 2 value of 0.9996.
  • the slope of the line is 0.273 ⁇ 0.002 ⁇ /g.
  • the mass of an unknown sample of salt could be calculated by dividing its measured activity by this slope.
  • the 22 Na activity measurements were also performed on the lower-efficiency GC1419 detector as a check on the GC5019 results.
  • the results using the GC1419 detector are summarized in Table III.
  • a plot of the 22 Na activity versus the mass of the salt is shown in FIG. 8 for the GC 1419 detector.
  • a 20.0054 gram sample of LiCl-KCl salt was prepared for use.
  • a total of 5.49 ⁇ 0.07 ⁇ of 22 NaCl was added to the salt.
  • Two HPGe detectors were used to eliminate any potential system errors. Results from two detector systems agree with each other very well. From one detector, a least-squares fit of the data yields a line through the origin with an R 2 value of 0.9996. The slope of the line, which is the activity of the sample, A s , divided by the mass of the sample, M s , is 0.273 ⁇ 0.002 ⁇ /g.
  • the mass, M, of an initial (assumed unknown) sample of salt could be calculated by dividing its measured activity, As, by this slope (i.e., 5.49 ⁇ /(0.273 ⁇ /g)), which yields 20.1099 ⁇ 0.2564 gram.
  • This measured value through activity falls into the mass of the original salt measured with a balance within 1 sig statistical region, validating the radioactive tracer dilution technique. Further studies applying different radioisotopes may be performed because of the interference peaks at the 22 Na photo peak, 1275 keV, from the fission products in an actual molten salt.
  • a mixture of 22 Na and 154 Eu was added to a first crucible (crucible 0) inside a glovebox having conditions of 4.1 ppm C and 0.2 ppm H2O.
  • a eutectic mixture of LiCl- KC1 (45 weight percent LiCl and 55 weight percent KC1) was added to the crucible.
  • the crucible was heated to about 550°C for a duration of about 16 hours, during which the liquid (e.g., molten) salt was stirred.
  • the crucible and salt were allowed to cool, after which pieces of the salt and tracer were placed in a second crucible (crucible 1) and a third crucible (crucible 3), while a portion of the original salt and tracer remained in the first crucible (labeled crucible 2 in the Table IV and Table V below after a portion of the salt was removed therefrom).
  • the 22 Na activity was determined with it main peak at 1,274.54 keV masked by the interfering 154 Eu.
  • the intensity and efficiency information for all peaks of the 154 Eu, and the intensity and efficiency of the 1274.54 keV peak of 22 Na were used to determine the counts at 1274.54 keV attributed to the presence of the 22 Na. Stated another way, the counts at 1274.54 keV attributed to the 154 Eu were subtracted from the total number of counts at 1274.54 keV to determine the activity attributed to the 22 Na tracer.
  • the mass of salt was determined according to Equation (3) above. Accordingly, the mass of an unknown amount of a molten salt was determined with a tracer exhibiting an activity at an energy overlapping an activity energy of at least one component of the molten salt.
  • Embodiment 1 A method for determining the mass of a molten salt in a container comprising: adding an amount of a radioactive isotope tracer with known activity and known mass into the molten salt; mixing the radioactive isotope tracer with the molten salt until homogeneous; obtaining a sample of the radioactive isotope tracer and molten salt mixture; weighing the sample obtained; measuring the activity of the sample obtained using gamma spectrometry; and calculating the molten salt mass using radioactive isotope tracer dilution analysis.
  • Embodiment 2 The method of Embodiment 1, wherein the molten salt is contained in a container with a non-geometrically shaped cavity.
  • Embodiment 3 The method of Embodiment 1 or Embodiment 2, wherein the molten salt is contained in an electrorefiner.
  • Embodiment 4 The method of any one of Embodiments 1 through 3, wherein the radioactive isotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, and 168 Tm.
  • Embodiment 5 The method of any one of Embodiments 1 through 4, wherein the radioactive isotope tracer comprises a compound containing a radioactive isotope.
  • Embodiment 6 The method of Embodiment 5, wherein the compound is selected from the group consisting of CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCb.
  • Embodiment 7 The method of Embodiment 5, wherein the compound is selected from the group consisting of a fluoride salt, chloride salt, bromide salt, and iodide salt.
  • Embodiment 8 The method of any one of Embodiments 1 through 7, wherein the activity is measured using a high purity germanium detector.
  • Embodiment 9 A method for using radioactive isotope tracer dilution to determine the mass of a molten salt in a container comprising: adding a known mass ⁇ Mr) of a radioactive isotope tracer with a known activity ⁇ A r ) to the molten salt; mixing the radioactive isotope tracer with the molten salt until homogeneous; obtaining a sample of the radioactive isotope tracer and molten salt mixture; weighing the sample obtained (M s ); measuring the activity of the sample obtained (As) using gamma spectrometry; and
  • Embodiment 10 The method of Embodiment 9, wherein the molten salt is contained in a container with a non-geometrically shaped cavity.
  • Embodiment 11 The method of Embodiment 9 or Embodiment 10, wherein the molten salt is contained in an electrorefiner.
  • Embodiment 12 The method of any one of Embodiments 9 through 11, wherein the mass of molten salt is greater than 10 kg.
  • Embodiment 13 The method of any one of Embodiments 9 through 12, wherein the mass of the radioactive isotope tracer (Mr) is ignored and the molten salt mass (Msaii) is
  • Embodiment 14 The method of any one of Embodiments 9 through 13, wherein the radioactive isotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, and 168 Tm.
  • Embodiment 15 The method of any one of Embodiments 9 through 14, wherein the radioactive isotope tracer comprises a compound containing a radioactive isotope.
  • Embodiment 16 The method of Embodiment 15, wherein the compound is selected from the group consisting of CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCh.
  • Embodiment 17 The method of Embodiment 15, wherein the compound is selected from the group consisting of a fluoride salt, chloride salt, bromide salt, iodide salt, and combinations thereof.
  • Embodiment 18 The method of any one of Embodiments 9 through 15, wherein the activity is measured using a high purity germanium detector.
  • Embodiment 19 A method for determining the mass of a liquid in a container comprising: adding an amount of a radioactive isotope tracer with known activity and known mass into the liquid; mixing the radioactive isotope tracer with the liquid until homogeneous; obtaining a sample of the radioactive isotope tracer and liquid mixture; weighing the sample obtained; measuring the activity of the sample obtained using gamma spectrometry; and calculating the mass of the liquid using radioactive isotope tracer dilution analysis.
  • Embodiment 20 The method of Embodiment 19, wherein the liquid is contained in a container with a non-geometrically shaped cavity.
  • Embodiment 21 The method of Embodiment 19 or Embodiment 20, wherein the liquid is a molten salt.
  • Embodiment 22 The method of any one of Embodiments 19 through 21, wherein the molten salt is contained in an electrorefiner.
  • Embodiment 23 The method of any one of Embodiments 19 through 22, wherein the radioactive isotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, and 168 Tm.
  • Embodiment 24 The method of any one of Embodiments 19 through 23, wherein the radioactive isotope tracer comprises a compound containing a radioactive isotope.
  • Embodiment 25 The method of Embodiment 24, wherein the compound is selected from the group consisting of CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCh.
  • Embodiment 26 The method of Embodiment 24, wherein the compound is selected from the group consisting of a fluoride salt, chloride salt, bromide salt, iodide salt, and combinations thereof.
  • Embodiment 27 The method of any one of Embodiments 19 through 26, wherein the activity is measured using a high purity germanium detector.
  • Embodiment 28 A method for using radioactive isotope tracer dilution to determine the mass of a liquid in a container comprising: adding a known mass (Mr) of a radioactive isotope tracer with a known activity (A r ) to the liquid; mixing the radioactive isotope tracer with the liquid until homogeneous; obtaining a sample of the radioactive isotope tracer and liquid mixture; weighing the sample obtained (M s ); measuring the activity of the sample obtained (As) using gamma spectrometry; and calculating the mass of
  • Mr known mass
  • a r known activity
  • Embodiment 29 The method of Embodiment 28, wherein the liquid is contained in a container with a non-geometrically shaped cavity.
  • Embodiment 30 The method of Embodiment 28 or Embodiment 29, wherein the liquid is a molten salt.
  • Embodiment 31 The method of Embodiment 30, wherein the molten salt is contained in an electrorefiner.
  • Embodiment 32 The method of Embodiment 30, wherein the mass of molten salt is greater than 10 kg.
  • Embodiment 33 The method of any one of Embodiments 28 through 32, wherein the mass of the liquid (M) is greater than 10 kg.
  • Embodiment 34 The method of any one of Embodiments 28 through 33, wherein the mass of the radioactive isotope tracer (M r ) is ignored and the molten salt mass (M) is
  • Embodiment 35 The method of any one of Embodiments 28 through 34, wherein the radioactive isotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, and 168 Tm.
  • Embodiment 36 The method of any one of Embodiments 28 through 35, wherein the radioactive isotope tracer comprises a compound containing a radioactive isotope.
  • Embodiment 37 The method of Embodiment 36, wherein the compound is selected from the group consisting of CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCh.
  • Embodiment 38 The method of Embodiment 36, wherein the compound is selected from the group consisting of a fluoride salt, chloride salt, bromide salt, iodide salt, and combinations thereof.
  • Embodiment 39 The method of any one of Embodiments 28 through 38, wherein the activity is measured using a high purity germanium detector.
  • Embodiment 40 A method for determining a mass of a molten salt in a container, the method comprising: adding an amount of a radioactive isotope tracer with known activity and known mass into a molten salt in a container; mixing the radioactive isotope tracer with the molten salt to form a mixture; obtaining a sample of the mixture; weighing the sample; measuring the activity of the sample using gamma spectrometry; and calculating the molten salt mass based, at least in part, on the weight of the sample and the activity of the sample.
  • Embodiment 41 The method of Embodiment 40, wherein adding an amount of a radioactive isotope tracer with known activity and known mass into a molten salt in a container comprises adding the radioactive isotope tracer in a container with a
  • Embodiment 42 The method of Embodiment 40 or Embodiment 41, further comprising selecting the container to comprise an electrorefiner.
  • Embodiment 43 The method of any one of Embodiments 40 through 42, further comprising selecting the radioactive isotope tracer from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, 168 Tm, 7 Be, 2 P, 5 P, 5 S, 45 Ca, 48 V, 49 V, 54 Mn, 55 Fe, 59 Fe, 57 Co, 65 Zn, 68 Ge, 75 Se, 83 Rb, 85 Sr, 88 Zr, 88 Y, 109 Cd, 113 Sn, 170 Tm, 171 Tm, 173 Lu, 174 Lu, 172 Hf, 175 Hf, 179 Ta, 181 W, 188 W, 182 Ta, and 204 T1.
  • the radioactive isotope tracer from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, 168 Tm, 7 Be, 2 P, 5 P, 5
  • Embodiment 44 The method of any one of Embodiments 40 through 43, further comprising selecting the radioactive isotope tracer to comprise a compound containing a radioactive isotope.
  • Embodiment 45 The method of Embodiment 44, further comprising selecting the compound from the group consisting of CoCh, KBr, NaCl, RbCl, NaF, NaBr, Nal, and TmCh.
  • Embodiment 46 The method of Embodiment 44, further comprising selecting the compound from the group consisting of a fluoride salt, a chloride salt, a bromide salt, iodide salt, and combinations thereof.
  • Embodiment 47 The method of any one of Embodiments 40 through 46, wherein measuring the activity using gamma ray spectroscopy comprises measuring the activity using a high purity germanium detector.
  • Embodiment 48 The method of any one of Embodiments 40 through 47, wherein calculating the molten salt mass based, at least in part, on the weight of the sample and the activity of the sample comprises calculating the molten salt mass based on a ratio of the activity of the radioactive isotope tracer to the activity of the sample.
  • Embodiment 49 The method of any one of Embodiments 40 through 48, wherein calculating the molten salt mass based, at least in part, on the weight of the sample and the activity of the sample comprises calculating the molten salt mass according to the following equation:
  • Msait is the molten salt mass
  • a r is the activity of the radioactive isotope tracer
  • As is the activity of the sample
  • md M s is the mass of the sample.
  • Embodiment 50 The method of any one of Embodiments 40 through 49, further comprising selecting the mass of the radioactive isotope tracer to be less than about 0.1 percent a mass of the molten salt.
  • Embodiment 51 The method of any one of Embodiments 40 through 50, further comprising selecting the radioactive isotope tracer to comprise 22 Na.
  • Embodiment 52 The method of any one of Embodiments 40 through 51, further comprising determining a number of counts at one or more energies due to the radioactive isotope tracer.
  • Embodiment 53 The method of Embodiment 52, wherein determining a number of counts at one or more energies due to the radioactive isotope tracer comprises subtracting a number of counts at the one or more energies due to one or more materials of the molten salt.
  • Embodiment 54 The method of any one of Embodiments 40 through 53, further comprising selecting the container to comprise more than about 10.0 kg of molten salt.
  • Embodiment 55 The method of any one of Embodiments 40 through 54, further comprising selecting the container to exhibit a shape other than a right cylinder.
  • Embodiment 56 A system for determining a mass of a molten salt, the system comprising: an electrochemical cell comprising a molten salt; one or more spent nuclear fuels in the electrochemical cell; and a radioisotope tracer disposed substantially uniformly throughout the molten salt.
  • Embodiment 57 The system of Embodiment 56, wherein the radioisotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, 168 Tm, 7 Be, 32 P, 35 P, 35 S, 45 Ca, 48 V, 49 V, 54 Mn, 55 Fe, 59 Fe, 57 Co, 65 Zn, 68 Ge, 75 Se, 83 Rb, 85 Sr, 88 Zr, 88 Y, 109 Cd, 113 Sn, 170 Tm, 171 Tm, 173 Lu, 174 Lu, 172 Hf, 175 Hf, 179 Ta, 181 W, 188 W, 182 Ta, and 204 T1.
  • the radioisotope tracer is selected from the group consisting of 60 Co, 24 Na, 58 Co, 82 Br, 22 Na, 84 Rb, 86 Rb, 168 Tm, 7 Be, 32 P, 35 P, 35 S, 45 Ca
  • Embodiment 58 The system of Embodiment 56 or Embodiment 57, wherein the radioisotope tracer comprises 22 Na.
  • Embodiment 59 The system of any one of Embodiments 56 through 58, wherein the molten salt comprises spent nuclear fuel.
  • Embodiment 60 A method of determining a mass of a molten salt in a container, the method comprising: adding an amount of a radioactive isotope tracer with a known activity and a known mass into a molten salt in a container to form a mixture; obtaining a sample of the mixture; measuring the activity of the sample; subtracting an activity due to the molten salt from the activity of the sample to obtain a compensated activity of the sample; and determining a mass of the molten salt based, at least in part, on a weight of the sample and the compensated activity of the sample.

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Abstract

L'invention concerne un procédé de détermination de la masse d'un sel fondu dans un récipient avec une cavité non géométrique et un volume inconnu. Le procédé consiste à ajouter une quantité connue d'un traceur d'isotope radioactif ayant une activité connue dans le sel fondu, à mélanger le traceur d'isotope radioactif au sel fondu jusqu'à ce qu'il soit homogène, à obtenir un échantillon du mélange résultant, à mesurer l'activité de l'échantillon, et à calculer la masse totale de sel fondu à l'aide d'une analyse de dilution de traceur d'isotope radioactif.
PCT/US2018/025633 2017-04-03 2018-04-02 Système de détermination de masse de sel fondu, et procédés associés WO2018187194A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011071151A1 (fr) * 2009-12-10 2011-06-16 東ソー株式会社 Procédé de production d'un métal d'indium, cellule électrolytique en bain de sels fondus et procédé de purification d'un métal à basse température de fusion
US20160189813A1 (en) * 2014-12-29 2016-06-30 Terrapower, Llc Molten nuclear fuel salts and related systems and methods

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011071151A1 (fr) * 2009-12-10 2011-06-16 東ソー株式会社 Procédé de production d'un métal d'indium, cellule électrolytique en bain de sels fondus et procédé de purification d'un métal à basse température de fusion
US20160189813A1 (en) * 2014-12-29 2016-06-30 Terrapower, Llc Molten nuclear fuel salts and related systems and methods

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LANTELME, F.: "Molten Salts and Isotope Separation", Z. NATURFORSCH. A, vol. 68, no. 1-2, 15 February 2013 (2013-02-15), pages 39 - 47, XP055542784, Retrieved from the Internet <URL:https://pdfs.semantlescholar.org/3973/6265d22a1252c250acte02b115311c69d521.pdf> [retrieved on 20180530] *

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