Thorium peroxide-based generators for ac-225 generation

Patent metadata

Field	Value
Publication number	US-2022363557-A1
Application number	US-202217742116-A
Country	US
Kind code	A1
Filing date	May 11, 2022
Priority date	May 12, 2021
Publication date	Nov 17, 2022
Grant date	—

Abstract

The actinium generator described herein is based on peroxide precipitation of thorium from its daughter products radium and actinium. In this system, the “actinium generator” is a quantity of solid thorium peroxide stored under a cover solution. The thorium peroxide is stored as a suspension to allow for the buildup of the decay products radium and actinium in the suspension. The suspension is then treated with a peroxide solution and the solid and liquid phases are separated. The thorium remains in the solid peroxide form while the soluble actinium and radium are removed with the liquid phase in a rinsing step. After rinsing, an amount of the rinsing solution is retained with the thorium peroxide solid as a fresh cover solution to form another suspension for storage. This new suspension is then stored to allow actinium and radium to again build up in the suspension for a subsequent separation cycle.

First claim

What is claimed is:

1 . A method for generating 225 Ac and 225 Ra from 229 Th comprising:
providing a first suspension of solid 229 Th peroxide with a cover liquid solution; storing the first suspension for a first period of time during which at least some 229 Th decays into 225 Ac; and separating the solid 229 Th peroxide from at least some of the cover liquid solution of the first suspension to obtain a quantity of separated solid 229 Th peroxide and a first liquid solution containing at least some 225 Ac.

2 . The method of claim 1 further comprising:
after separating the solid 229 Th peroxide from the cover liquid, adding an amount of fresh cover liquid to the separated solid 229 Th peroxide to create a second suspension.

3 . The method of claim 2 further comprising:
storing the second suspension for a second period of time during which at least some 229 Th decays into 225 Ac; and
separating the solid 229 Th peroxide from at least some of the cover liquid solution of the second suspension to obtain a quantity of separated solid 229 Th peroxide and a second liquid solution containing at least some 225 Ac.

4 . The method of claim 1 wherein separating the solid 229 Th peroxide from the cover liquid solution further comprises:
agitating the first suspension or the second suspension prior to separating the solid 229 Th peroxide from the cover liquid solution.

5 . The method of any of claim 1 wherein separating the solid 229 Th peroxide from the cover liquid solution further comprises:
maintaining an excess amount of peroxide in the cover liquid solution.

6 . The method of claim 5 , wherein maintaining an excess amount of peroxide in the cover liquid solution comprises:
adding a H 2 O 2 solution to the first suspension or the second suspension prior to separating the solid 229 Th peroxide from the cover liquid solution.

7 . The method of claim 6 , wherein the H 2 O 2 solution is from 5% to 50% by weight H 2 O 2 .

8 . The method of claim 6 , wherein the H 2 O 2 solution is from 25% to 35% by weight H 2 O 2 .

9 . The method of claim 1 , wherein providing the first suspension comprises:
dissolving an amount of 229 ThCl 4 . x H 2 O or 229 Th(NO 3 ) 4 . x H 2 O in an acid solution to obtain a dissolved 229 Th solution; and adding an amount of H 2 O 2 to the dissolved 229 Th solution thereby forming solid 229 Th peroxide and a residue liquid phase; separating the solid 229 Th peroxide from the residue liquid phase; and adding the solid 229 Th peroxide to an acidic cover liquid solution to create the first suspension.

10 . The method of claim 1 , wherein separating the solid 229 Th peroxide from the cover liquid solution includes one or more of filtering, centrifuging, and gravity settling.

11 . The method of claim 1 , wherein the cover liquid solution is a NaNO 3 liquid solution.

12 . The method of claim 11 , wherein the cover liquid solution is a NaNO 3 solution of from 0.01 to 10.0 M NaNO 3 .

13 . The method of claim 1 , wherein the cover solution is a HNO 3 solution.

14 . The method of claim 13 , wherein the cover liquid solution is a HNO 3 solution of from 0.01 to 10.0 M HNO 3 .

15 . The method of claim 1 , wherein the first period of time is 25 days or less.

16 . The method of any of claims 1 - 18 , further comprising:
maintaining the first suspension and/or the second suspension at a pH from 0.5 to 3.

17 . The method of claim 19 or 20 , wherein maintaining the first suspension and the second suspension at a pH from 0.5 to 3 further comprises:
adding a solution of either KOH or HNO 3 as needed to the first suspension or the second suspension.

18 . A pharmaceutical composition comprising the 225 Ac generated by the method of claim 1 .

19 . A system for generating 225 Ac and 225 Ra from 229 Th comprising:
a vessel containing a suspension of solid 229 Th peroxide with a cover liquid.

20 . A 225 Ac generator, comprising:
a first portion of the generator; a column body defining an interior chamber; a first access port at the first portion of the generator providing access to the interior chamber; and an amount of solid 229 Th peroxide contained in the interior chamber.

Assignees

• Terrapower Llc

Inventors

• Czerwinski Ken
• Fitzgerald Hilary

Classifications

• G21G1/001 Primary

  Recovery of specific isotopes from irradiated targets · CPC title

• C22B60/0295

  obtaining other actinides except plutonium · CPC title

• G21G2001/0094

  Other isotopes not provided for in the groups listed above · CPC title

• G21G2001/0089

  Actinium · CPC title

• G21G1/0005 Primary

  Isotope delivery systems (use of radioisotopes as tracers G21H5/02) · CPC title