Patent Application
20190371482
A molten salt reactor is a class of nuclear fission reactor in which the primary nuclear reactor coolant or the fuel is a molten salt mixture. Often molten salt reactors run at higher temperatures than water-cooled reactors and, therefore, can produce a higher thermodynamic efficiency while staying at low vapor pressure. In addition, molten salt reactors can produce interesting and useful fission byproducts products.
Some embodiments of the invention include an chemical separation mechanism for a molten salt reactor; the molten salt in the reactor may include some fission products. In some embodiments, the chemical separation mechanism may include a molten salt receptacle with a molten salt disposed within, a solvent receptacle having a solvent disposed within; an electrode; and an electrode mechanism. In some embodiments, the electrode mechanism may be configured to submerse the electrode into the molten salt receptacle such that a chemical reaction occurs between the electrode and one or more of the fission products in the molten salt. In some embodiments, the electrode mechanism may submerse the electrode into the solvent receptacle such that a chemical reaction occurs resulting in one or more of the fission products being deposited into the solvent.
In some embodiments, the electrode mechanism comprises a raise and swivel gantry. In some embodiments, the electrode mechanism comprises a raise and slide electrode mechanism.
In some embodiments, the chemical separation mechanism may include a power source configured to place an electrical potential on the electrode(s).
In some embodiments, the molten salt comprises an actinide bearing salt, and wherein the electrode does not react with the actinides within the actinide bearing salt. In some embodiments, the molten salt comprises an actinide bearing salt. In some embodiments, the molten salt comprises a fluoride or chloride salt.
In some embodiments, the fission products may be plated on the electrode when the electrode is placed within the molten salt receptacle.
In some embodiments, the electrode may include uranium. In some embodiments, the electrode may include an actinide.
In some embodiments, the chemical separation mechanism may include a second electrode disposed within or in contact with the molten salt within the molten salt receptacle. In some embodiments, the second electrode may be disposed within or in contact with the solvent within the solvent receptacle.
In some embodiments, the chemical separation chamber encloses a noble gas.
Some embodiments of the invention may include a method comprising exposing an electrode to a molten salt comprising fission products such that an chemical reaction occurs between the electrode and one or more of the fission products in the molten salt; removing the electrode to the molten salt; and exposing the electrode to a solvent such that a chemical reaction occurs resulting in one or more of the fission products being deposited into the solvent. The method may also include removing the electrode from the solvent. In some embodiments, the method may include providing an electric potential to the electrode while the electrode is exposed to the molten salt. In some embodiments, the method may include providing an electric potential to the electrode while the electrode is exposed to the solvent.
In some embodiments, exposing the electrode to the molten salt comprises operating a raise and swivel gantry. In some embodiments, exposing the electrode to a molten salt comprises operating a raise and slide electrode mechanism.
In some embodiments, the molten salt comprises an actinide bearing salt, and the electrode does not react with the actinides within the actinide bearing salt. In some embodiments, the molten salt comprises an actinide bearing salt.
In some embodiments, the electrode may include uranium.
These and other features, aspects, and advantages of the present disclosure are better understood when the following Detailed Description is read with reference to the accompanying drawings.
Some embodiments of the disclosure include an chemical separation mechanism that includes a molten salt receptacle and a solvent receptacle. The molten salt receptacle may include or contain a molten salt having fission products. The solvent receptacle may include or contain a solvent. The chemical separation mechanism may include an electrode and an electrode mechanism configured to submerse the electrode into the molten salt receptacle and submerse the electrode into the solvent receptacle. The electrode mechanism may include any type of electro-mechanical electrode mechanisms or electronics to move the electrode from various positions. The electrode may react or bond with some of the fission products in the molten salt in the molten salt receptacle. The electrode may react or bond with the solvent in the solvent receptacle such that fission products bonded with the electrode can be deposited or released into the solvent.
An chemical separation mechanism can be utilized in any type of molten salt system or device including, but not limited to, thermal spectrum nuclear reactors, fast spectrum nuclear reactors, epithermal spectrum nuclear reactors, molten salt test loops, molten salt targets, molten salt neutron sources, etc. In some embodiments, the solvent comprises Ethelene Glycol. In some embodiments, the solvent comprises choline chloride.
In some embodiments, the chemical separation mechanism can include a raise and swivel gantry or a raise and slide electrode mechanism to move the electrode from one position to another. Various other robotic or electro-mechanical devices may be used.
Systems and methods are disclosed for electrochemical separation in a molten salt chamber. A molten salt reactor may be a nuclear fission reactor in which the primary nuclear reactor coolant, or even the fuel itself, is a molten salt mixture. In some embodiments, molten salt reactors can run at higher temperatures than water-cooled reactors for a higher thermodynamic efficiency, while staying at low vapor pressure. In some embodiments, the fuel in a molten salt reactor may include a molten mixture of fluoride salts (e.g., lithium fluoride and beryllium fluoride (FLiBe)) with dissolved uranium (U-235 or U-233) fluorides (UF4). In some embodiments, the uranium may be low-enriched uranium, unenriched uranium, or enriched uranium.
The reactor 102 may include any type of molten salt fission device or system whether or not it includes a reactor. The reactor 102 may include a liquid-salt very-high-temperature reactor, a liquid fluoride thorium reactor, a liquid chloride thorium reactor, a liquid salt breeder reactor, a liquid salt solid fuel reactor, a high flux water reactor with a high or low enriched uranium-salt target etc.
The molten salt reactor system 100, for example, may employ one or more molten salts with a fissile material. The molten salt, for example, may include any salt comprising fluorine, chlorine, lithium, sodium, potassium, beryllium, zirconium, rubidium, etc., or any combination thereof. Some examples of molten salts may include LiF, LiF—BeF2, 2LiF—BeF2, LiF—BeF2—ZrF4, NaF—BeF2, LiF—NaF—BeF2, LiF—ZrF4, LiF—NaF—ZrF4, KF—ZrF4, RbF—ZrF4, LiF—KF, LiF—RbF, LiF—NaF—KF, LiF—NaF—RbF, BeF2—NaF, NaF—BeF2, LiF—NaF—KF, etc. In some embodiments, the molten salt may include sodium fluoride, potassium fluoride, aluminum fluoride, zirconium fluoride, lithium fluoride, beryllium fluoride, rubidium fluoride, magnesium fluoride, and/or calcium fluoride
In some embodiments, the molten salt may include any of the following possible salt eutectics. Many other eutectics may be possible. The following list also includes molar ratios and the melting point of the example eutectics. The molar ratios are examples only. Various other eutectics may be used.
The reactor 102 may include a reactor blanket 105 that surrounds a reactor core 110. A plurality of rods 115 may be disposed within the reactor core 110. The reactor core 110, for example, may include a Uranium rich molten salt such as, for example, UF4—FLiBe. The reactor blanket 105 may include a breeding fuel that can produce Uranium for the reactor core 110. The reactor blanket 105 may include a thorium rich fluoride salt. For example, the reactor blanket 105 may include thorium-232, which through neutron irradiation becomes thorium-233. Thorium-233 has a half-life of 22 minutes and through beta decay becomes protactinium-233. Then, through a second beta decay protactinium-233, which has a half-life of 26.97 days, becomes uranium-233, which is additional fuel for the reactor core 110.
The rods 115 may include any material that may act as a neutron energy moderator such as, for example, graphite, ZrHx, light water, heavy water, beryllium, lithium-7, etc. The neutron energy moderator may be selected or not used at all based on the desire for a thermal, epithermal, or fast spectrum neutrons within the reactor core 110.
In some embodiments, the molten salt reactor system 100 may include a chemical separation subsystem. The chemical separation subsystem, for example, may include a chemical separation chamber 120 and/or a chemical separation loop 125. The chemical separation subsystem, for example, may be used to extract fission products (e.g., molybdenum, ruthenium) from the molten salt and purify the fission products. A list of fission products can be found, for example, at https://www-nds.iaea. org/wimsd/fpyield.htm#T1 and/or at https://www-nds.iaea.org/wimsd/fpyield.htm#T2. Other fission products may be included. The chemical separation subsystem, for example, may remove fission products without removing actinides (e.g., Uranium isotopes such as, for example, Uranium 233, Uranium 235; or Plutonium isotopes such as, for example, Plutonium 239; or Thorium isotopes; etc.) from the reactor core.
The safety subsystem may include an emergency dump conduit 170, a freeze plug 160, or one or more emergency dump tanks 165. The emergency dump tanks 165 are connected with the reactor core 110 via the emergency dump conduit 170. The freeze plug 160 may be an active element that keeps the fissile material within the reactor core 110 unless there is an emergency. If the freeze plug 160, for example, loses power or is otherwise triggered, the dump conduit is opened and the material in the reactor core 110 is dumped into the emergency dump tanks 165. The emergency dump tanks 165 may include materials such as, for example, energy moderating materials. The emergency dump tanks 165, for example, may be placed in a location where any reactions can be controlled. The emergency dump tanks 165, for example, may be sized to preclude the possibility of a sustained reaction.
In some embodiments, the molten salt surface 225 within the molten salt chemical separation channel 205 may separate the molten salt chemical separation channel 205 and the chemical separation chamber 260. In some embodiments, the chemical separation chamber 260 may be filled with an inert gas or a vacuum that may, for example, keep the molten salt surface 225 from being exposed to unwanted reactions or oxidation.
In some embodiments, an electrode 230 may be dipped within the molten salt within the molten salt chemical separation channel 205. The electrode 230 may include actinide such as, for example, Uranium. The electrode may be coupled with a raise and swivel gantry 235. The raise and swivel gantry 235 may be a mechanical electrode mechanism that raises the electrode 230 (see
In some embodiments, an electrical potential may be placed on the electrode 230 while the electrode is in contact with the molten salt (e.g., actinide bearing salt). In some embodiments, an electrical potential may not be required and the electrode 230 will merely be a conductor while the electrode is in contact with the molten salt. In some embodiments, the electric potential may be a direct current or an alternating current electrical potential. A second electrode may be in contact with the molten salt to complete (or ground) the circuit. The second electrode can be an electrode coupled with any portion of the chemical separation subsystem 200 or may be part of a vessel wall of the chemical separation subsystem 200. For example, the second electrode may be part of the vessel wall of the molten salt chemical separation channel 205 and/or the vessel wall of the molten salt loop conduit 220. The electric potential between the electrode 230 and the second electrode may produce or enhance an electrochemical reaction between fission products within the molten salt and the electrode 230. In some embodiments, the electrochemical reaction may cause fission products to plate on the electrode 230. In some embodiments, the electric potential between the electrodes may vary from as low as 0 volts to as high as 6 volts. The electric potential may vary in order to select which elements are expected to be plated on the electrode 230.
In some embodiments, the magnitude of the electric potential, the magnitude of the current applied to the electric potential, the composition of the molten salt, the type and composition of the fission products dissolved in the salt, and/or the material comprising the electrode 230 may determine the reactants that react with the electrode 230. Additionally or alternatively, in some embodiments, the frequency of an alternating electric potential, the frequency of the alternating current applied to the electric potential, the composition of the molten salt, and/or the material comprising the electrode 230 may determine the reactants that react with the electrode 230
In some embodiments, the raise and swivel gantry 235 may be disposed partially within the chemical separation chamber 260. In some embodiments, one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. may be coupled with and/or part of the raise and swivel gantry 235. In some embodiments, the one or more of motors, actuators, gears, pulleys, solenoids, cables, etc. may be disposed external to the chemical separation chamber 260 that cause the raise and swivel gantry 235 to raise and/or swivel the electrode 230.
In some embodiments, the chemical separation chamber 260 may include a getter 250 that may include a getter plug. The getter may be used to remove gases from within the chemical separation chamber 260. The getter 250, for example, may include magnesium carbonate, depleted uranium, silver, or copper etc. In some embodiments, the getter may collect various chemicals, especially gasses such as tritium, hydrogen, deuterium, iodine, krypton, xenon, zirconium, molybdenum, helium, etc. In some embodiments, the getter 250 may use a pneumatic or mechanical system to remove and/or replace the (potentially saturated) getter in order to pull out chemicals from the chemical separation chamber 260.
In some embodiments, the chemical separation chamber 260 may include a gaseous release port 255. The gaseous release port 255, for example, may collect gaseous products from the chemical separation chamber 260 such as, for example, krypton, xenon, iodine, helium, molybdenum, zirconium, etc.
In some embodiments, either the first electrode or the second electrode may comprise an anode and the other electrode may comprise a cathode. In some embodiments, a third electrode may be included that may be a reference electrode. In some embodiments, a third electrode may be included the may be an additional anode or an additional cathode.
In some embodiments, the solvent receptacle 240 may be coupled with a solvent processing subsystem such as, for example, via a tube and/or a solenoid that allows the solvent 241 to flow from the solvent receptacle 240 to the solvent processing subsystem. In some embodiments, the fission products may be separated from the solvent and/or further processed.
At block 710 an electrical potential is provided to the electrode. The electrical potential, for example, may vary in voltage and/or frequency depending on the type of molten salts, the molten salt mixture, and/or the type of fission products desired to extract from the molten salt. The electric potential, for example, may be a potential between the electrode and a second electrode disposed elsewhere in the molten salt. The electric potential between the electrode and the second electrode may produce an electrochemical reaction between fission products within the molten salt and the electrode. In some embodiments, the electrochemical reaction may cause fission products to be plated on the electrode.
At block 715 the electrode may be removed from the molten salt. This can be accomplished in any number of ways. For example, the electrode may be removed using a raise and swivel gantry. As another example, the electrode may be removed using one or more of motors, actuators, gears, pulleys, solenoids, etc. As another example, the electrode may be removed from the molten salt by removing the molten salt.
At block 720 the electrode may be exposed to a solvent. For example, the electrode can be moved to a solvent receptacle. As another example, the chamber where the electrode is disposed may be filled with a solvent after the molten salt has been removed.
At block 725 the electrode may be exposed to an electrical potential. In some embodiments, the electrical potential provided while the electrode is disposed in the solvent may be reversed relative to the electrical potential provided at block 710. In some embodiments, the electrical potential, for example, may vary in voltage and/or frequency depending on the solvent composition and/or the type of fission products. The electric potential, for example, may be a potential between the electrode and a third electrode disposed elsewhere in the solvent. The electric potential between the electrode and the third electrode may produce an electrochemical reaction between fission products plated on the electrode such that the fission products are dissolved in the solvent.
At block 730 the electrode may be removed from the solvent.
The process 700 may be repeated any number of times. The process 700 may also include additional blocks or steps. In addition or alternatively, any number of blocks of the process 700 may be removed or deleted.
In some embodiments, an electrode may be held stationary within a chemical separation subsystem. Molten salt and solvent may alternately flow into the chemical separation subsystem as electrical potential on the electrode is correspondingly reversed to collect fission material from the molten salt and dissolve fission material in the solvent.
In some embodiments, more than one electrode may be used. In some embodiments, a power source may be included that is configured to place an electrical potential on the electrode(s). The electric potential may produce an electrochemical reaction between electrode and the fission products within the molten salt or the electrode and the solvent. In some embodiments, the fission products are plated on the electrode when the electrode is placed or submersed within the molten salt receptacle.
In some embodiments, the molten salt comprises an actinide bearing salt, and wherein the electrode comprises a material that does not react with the actinides within the actinide bearing salt. In some embodiments, the molten salt comprises a fluoride salt or a chloride salt. In some embodiments, the electrode comprises an actinide.
In some embodiments, the chemical separation mechanism may also include a chemical separation chamber, wherein at least a portion of the electrode mechanism is disposed within the chemical separation chamber.
In some embodiments, the chemical separation chamber contains a noble gas.
In some embodiments, a mesh is used to collect precipitated particles within the solvent receptacle.
In some embodiments a secondary chamber may be used to perform chemical cleaning of the salts.
Unless otherwise specified, the term “substantially” means within 5% or 10% of the value referred to or within manufacturing tolerances. Unless otherwise specified, the term “about” means within 5% or 10% of the value referred to or within manufacturing tolerances.
Numerous specific details are set forth herein to provide a thorough understanding of the claimed subject matter. However, those skilled in the art will understand that the claimed subject matter may be practiced without these specific details. In other instances, methods, apparatuses or systems that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter.
The system or systems discussed herein are not limited to any particular hardware architecture or configuration.
The use of “adapted to” or “configured to” herein is meant as open and inclusive language that does not foreclose devices adapted to or configured to perform additional tasks or steps. Additionally, the use of “based on” is meant to be open and inclusive, in that a process, step, calculation, or other action “based on” one or more recited conditions or values may, in practice, be based on additional conditions or values beyond those recited. Headings, lists, and numbering included herein are for ease of explanation only and are not meant to be limiting.
While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, it should be understood that the present disclosure has been presented for purposes of example rather than limitation, and does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art.
| Number | Date | Country | |
|---|---|---|---|
| 62678235 | May 2018 | US |
