High assay, low enriched uranium deconversion process
AssigneeTerraPower, LLC
InventorClifford James Yeager
Life of this patent
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Abstract
A novel semi-batch process for deconverting high assay low enriched uranium (HALEU) from its uranium hexafluoride state to uranium dioxide and other chemical states useful as feeds for nuclear fuel in a nuclear reactor is provided. The semi-batch process enables the use of equipment that is small enough, and production rates that are low enough, to meet nuclear criticality safety restraints for HALEU, while enabling the safe, dependable, and economical production of HALEU feed for nuclear fuel at a nominal capacity of up to about 20 MTU (metric tons of uranium metal) per year per deconversion reactor.
Claims21
A semi-batch process for deconversion of fluorinated HALEU material to produce HALEU feed for nuclear fuel, comprising the following steps:
- a) providing a seed bed of uranium dioxide (UO2) powder in a fluidized bed reactor vessel, wherein the UO2 powder comprises uranium that includes greater than 5% by weight U-235 isotope;
- b) fluidizing the UO2 powder in the reactor vessel using an upflow stream comprising an inert gas, while heating the reactor vessel;
- c) feeding a stream of hydrogen and steam to the upflow stream of inert gas;
- d) feeding vaporized uranium hexafluoride (UF6) and additional steam to the fluidized bed reactor vessel, wherein the UF6 comprises uranium that includes greater than 5% by weight U-235 isotope;
- e) reacting the UF6 with some of the steam to yield uranyl fluoride (UO2F2);
- f) reacting the UO2F2 with the hydrogen in the upflow stream to yield additional UO2 powder which accumulates in the fluidized bed;
- g) stopping, when the UO2 in the fluidized bed reaches a target mass, the feeding of UF6 and additional steam and allowing any residual UF6 in the reactor vessel to react with the stream of hydrogen and steam to yield additional UO2 powder which accumulates in the fluidized bed;
- and
- h) stopping the stream of hydrogen and steam to enable discharge of a quantity of the UO2 powder from the reactor vessel.
A semi-batch process for deconversion of fluorinated HALEU material to produce HALEU feed for nuclear fuel, comprising the following steps:
- a) providing a seed bed of uranium dioxide (UO2) powder in a fluidized bed reactor vessel, wherein the UO2 powder comprises uranium that includes at least about 10% by weight U-235 isotope;
- b) fluidizing the UO2 powder in the reactor vessel using an upflow stream comprising nitrogen gas, while heating the reactor vessel to a temperature of at least about 450° C. in a top portion of the reactor vessel and 600° C. in a bottom portion of the reactor vessel
- c) feeding a stream of hydrogen and steam into the upflow stream of inert gas;
- d) feeding vaporized uranium hexafluoride (UF6) and additional steam in the top portion of the fluidized bed reactor vessel, wherein the UF6 comprises uranium that includes at least about 10% by weight U-235 isotope;
- e) hydrolyzing the UF6 in an upper portion of the fluidized bed reactor vessel to yield uranyl fluoride (UO2F2);
- f) reacting the UO2F2 with the hydrogen in the upflow stream to yield additional UO2 powder which accumulates in the fluidized bed;
- g) stopping, when the UO2 in the fluidized bed reaches a target mass, the feeding of UF6 and additional steam and allowing any residual UF6 in the reactor vessel to react with the stream of hydrogen and steam to yield additional UO2 powder which accumulates in the fluidized bed;
- and
- h) stopping the stream of hydrogen and steam to enable discharge of a quantity of the UO2 powder from the reactor vessel.
A semi-batch process for deconversion of fluorinated HALEU material to produce HALEU feed for nuclear fuel, comprising the following steps:
- a) providing a seed bed of uranium dioxide (UO2) powder in a fluidized bed reactor vessel, wherein the UO2 powder comprises uranium that includes about 19.75% by weight U-235 isotope;
- b) fluidizing the UO2 powder in the reactor vessel using an upflow stream comprising an inert gas, while heating the reactor vessel;
- c) feeding a stream of hydrogen and steam to the upflow stream of inert gas;
- d) feeding vaporized uranium hexafluoride (UF6) and additional steam to the fluidized bed reactor vessel, wherein the UF6 comprises uranium that includes about 19.75% by weight U-235 isotope;
- e) reacting the UF6 with some of the steam to yield uranyl fluoride (UO2F2);
- f) reacting the UO2F2 with the hydrogen in the upflow stream to yield additional UO2 powder which accumulates in the fluidized bed;
- g) stopping, when the UO2 in the fluidized bed reaches a target mass, the feeding of UF6 and additional steam and allowing any residual UF6 in the reactor vessel to react with the stream of hydrogen and steam to yield additional UO2 powder which accumulates in the fluidized bed;
- and
- h) stopping the stream of hydrogen and steam to enable discharge of a quantity of the UO2 powder from the reactor vessel.
Dependencies are inferred from the claim text.