Recovering and recycling uranium used for production of molybdenum-99

Patent metadata

Field	Value
Publication number	US-9842664-B2
Application number	US-201314038424-A
Country	US
Kind code	B2
Filing date	Sep 26, 2013
Priority date	Sep 26, 2013
Publication date	Dec 12, 2017
Grant date	Dec 12, 2017

Abstract

A processes for recycling uranium that has been used for the production of molybdenum-99 involves irradiating a solution of uranium suitable for forming fission products including molybdenum-99, conditioning the irradiated solution to one suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina. Another process involves irradiation of a solid target comprising uranium, forming an acidic solution from the irradiated target suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina.

First claim

What is claimed is:

1. A process for recycling uranium that has been used for the production of molybdenum-99 (Mo-99), comprising:
providing an aqueous solution comprising a first nitric acid concentration and a first uranium concentration;
irradiating the aqueous solution to produce soluble fission products comprising Mo-99;
adjusting the first uranium concentration to a second uranium concentration suitable for formation of uranyl nitrate hydrate crystals;
adding an inorganic oxidant to the aqueous solution to ensure that the Mo-99 is in a +VI oxidation state;
inducing the formation of uranyl nitrate hydrate crystals and a supernatant; and
separating the uranyl nitrate hydrate crystals from the supernatant.

2. The process of claim 1 , wherein the uranium is low enriched uranium.

3. The process of claim 1 , wherein the inducing the formation of uranyl nitrate hydrate crystals comprises cooling the aqueous solution to a temperature effective for the formation of the uranyl nitrate hydrate crystals.

4. The process of claim 1 , wherein the inducing formation of uranyl nitrate hydrate crystals comprises evaporating the aqueous solution under reduced pressure.

5. The process of claim 1 , further comprising separating the Mo-99 from the supernatant after separating the uranyl nitrate hydrate crystals from the supernatant.

6. The process of claim 1 , further comprising purifying the uranyl nitrate hydrate crystals after separating the uranyl nitrate hydrate crystals from the supernatant.

7. A process for recycling uranium that has been used for the production of Mo-99, comprising:
providing an aqueous solution comprising a nitric acid concentration of about 0.01 M to about 0.5 M, and a uranium concentration of about 80 to 310 gU/L;
irradiating the aqueous solution to produce soluble fission products comprising Mo-99;
adjusting the nitric acid concentration to about 4 M to about 8 M and the uranium concentration to about 350 to 650 gU/L;
adding an inorganic oxidant to the aqueous solution to ensure that the Mo-99 is in a +VI oxidation state;
inducing formation of uranyl nitrate hydrate crystals and a supernatant; and
separating the uranyl nitrate hydrate crystals from the supernatant, the supernatant comprising the soluble fission products.

8. The process of claim 7 , wherein the uranium is low enriched uranium.

9. The process of claim 7 , wherein the inducing the formation of uranyl nitrate hydrate crystals comprises cooling the aqueous solution to a temperature effective for the formation of the uranyl nitrate hydrate crystals.

10. The process of claim 7 , wherein the inducing formation of uranyl nitrate hydrate crystals comprises evaporating the aqueous solution under reduced pressure.

11. The process of claim 7 , further comprising separating the Mo-99 from the supernatant after separating the uranyl nitrate hydrate crystals from the supernatant.

12. The process of claim 7 , further comprising purifying the uranyl nitrate hydrate crystals after separating the uranyl nitrate hydrate crystals from the supernatant.

13. The process of claim 7 , further comprising:
preparing a second aqueous solution from the uranyl nitrate hydrate crystals, the second aqueous solution comprising a second nitric acid concentration of about 0.01 M to about 0.5 M, and a second uranium concentration of about 80 to 310 gU/L;
irradiating the second aqueous solution to produce soluble fission products comprising Mo-99;
adjusting the second nitric acid concentration to about 4 M to about 8 M, and the second uranium concentration to about 350 to 650 gU/L;
inducing formation of a second batch of uranyl nitrate hydrate crystals and a second supernatant from the second aqueous solution, the second supernatant comprising soluble fission products comprising Mo-99; and
separating the second batch of uranyl nitrate hydrate crystals from the second supernatant.

14. The process of claim 13 , further comprising separating Mo-99 from the second supernatant.

15. A process for recycling uranium that has been used for the production of Mo-99, comprising:
irradiating a solid target comprising uranium to produce fission products comprising Mo-99;
forming an aqueous acidic solution from the solid target, the aqueous acidic solution comprising a uranium concentration and a nitric acid concentration;
adjusting the nitric acid concentration to about 4 M to about 8 M, and the uranium concentration to about 350 to 650 gU/L;
inducing formation of uranyl nitrate hydrate crystals and a supernatant;
adding an inorganic oxidant to the supernatant to ensure that the Mo-99 is in a +VI oxidation state; and
separating the uranyl nitrate hydrate crystals from the supernatant.

16. The process of claim 15 , wherein the uranium is low enriched uranium.

17. The process of claim 15 , wherein the inducing formation of uranyl nitrate hydrate crystals comprises cooling the aqueous acidic solution to a temperature effective for formation of the uranyl nitrate hydrate crystals.

18. The process of claim 15 , wherein the inducing formation of uranyl nitrate hydrate crystals comprises evaporating the aqueous acidic solution under reduced pressure.

19. The process of claim 15 , further comprising separating Mo-99 from the supernatant after separating the uranyl nitrate hydrate crystals from the supernatant.

20. The process of claim 15 , further comprising purifying the uranyl nitrate hydrate crystals after separating the uranyl nitrate hydrate crystals from the supernatant.

Assignees

• Los Alamos Nat Security Llc

Inventors

• Reilly Sean Douglas
• May Iain
• Copping Roy
• Dale Gregory Edward

Classifications

• Y02W30/883

  Cross-Sectional Technologies · mapped topic

• G21C19/46

  Aqueous processes {, e.g. by using organic extraction means, including the regeneration of these means} · CPC title

• G21G2001/0042

  Technetium · CPC title

• G21G2001/0036

  Molybdenum · CPC title

• G21G1/04 Primary

  outside nuclear reactors or particle accelerators · CPC title