Diffusion window for radioactive heat source

Patent metadata

Field	Value
Publication number	US-11894158-B2
Application number	US-202117150556-A
Country	US
Kind code	B2
Filing date	Jan 15, 2021
Priority date	Jul 30, 2020
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Sealed containers for radioactive material are presented herein. A sealed container forms an interior envelope for housing a radioactive material and prevents escape of the radioactive material into a surrounding environment. The sealed container provides a diffusion window for gaseous decay products to escape at a particular diffusion rate. In one example, an apparatus, comprises a container forming a sealed interior envelope for a radioactive material. The container has an aperture covered by a window material, and properties of the window material are selected to provide for diffusion of at least one gas produced by radioactive decay of the radioactive material.

First claim

What is claimed is:

1. An apparatus, comprising:
a container forming a sealed interior envelope for a radioactive material and having an aperture covered by a window material;
the window material comprising properties selected to provide for diffusion of an isotope of helium produced by radioactive decay of the radioactive material; and
a control system configured to selectively alter the properties of the window material to provide for the diffusion of the isotope of helium according to a selected diffusion rate.

2. The apparatus of claim 1 , wherein the window material comprises a material comprising at least one among glass, silicon dioxide (SiO 2 ), fused silica, or polymer.

3. The apparatus of claim 1 , wherein the properties of the window material are selected to provide a diffusion rate of the isotope of helium through the window material approximately commensurate with the production rate of the isotope of helium from the radioactive decay.

4. The apparatus of claim 1 , wherein the radioactive material comprises tritium, and wherein the isotope of helium comprises helium-3.

5. The apparatus of claim 4 , wherein the tritium is included in a metallic material to form a hydride.

6. The apparatus of claim 1 , wherein the radioactive material produces alpha particles as a decay product that form helium-4 as the isotope of helium.

7. The apparatus of claim 1 , wherein heat energy produced by the radioactive decay of the radioactive material is coupled to a device that converts the heat energy to electrical energy.

8. The apparatus of claim 1 , wherein decay products produced by the radioactive decay of the radioactive material are converted to electrical energy.

9. The apparatus of claim 1 , wherein the window material comprises a laminated arrangement comprising a diffusion material that provides for the diffusion of the isotope of helium and a structural material that provides rigidity to the diffusion material and is porous to the isotope of helium.

10. The apparatus of claim 1 , comprising:
wherein the properties of the window material are selected to provide for the diffusion having a rate at or below a threshold rate; and
wherein the properties of the window material are selectively altered to provide for the selected diffusion rate as higher than the threshold rate.

11. The apparatus of claim 1 , comprising:
the control system configured to alter a temperature of the window material to produce the selected diffusion rate.

12. A method, comprising:
forming a container having a sealed interior envelope for a radioactive material and having an aperture covered by a window material;
wherein properties of the window material are selected to provide for diffusion of an isotope of helium produced by radioactive decay of the radioactive material; and
selectively altering temperature properties of the window material to provide for the diffusion of the isotope of helium according to a selected diffusion rate.

13. The method of claim 12 , wherein the properties of the window material are selected to provide a diffusion rate of the isotope of helium through the window material approximately commensurate with the production rate of the isotope of helium from the radioactive decay.

14. The method of claim 12 , wherein the radioactive material comprises tritium, and wherein the isotope of helium comprises helium-3, and wherein the tritium is included in a metallic material to form a hydride.

15. The method of claim 12 , wherein the radioactive material produces alpha particles as a decay product that form helium-4 as the isotope of helium.

16. The method of claim 12 , further comprising:
coupling heat energy produced by the radioactive decay of the radioactive material through a selected wall of the container to a device that converts the heat energy to electrical energy.

17. The method of claim 12 , further comprising:
forming the window material using a laminated arrangement comprising a diffusion material that provides for the diffusion of the isotope of helium and a structural material that provides rigidity to the diffusion material and is porous to the isotope of helium.

18. The method of claim 12 , wherein the properties of the window material are selected to provide for the diffusion having a rate at or below a threshold rate; and
wherein the temperature properties of the window material are selectively altered to provide for the selected diffusion rate as higher than the threshold rate.

19. A system, comprising:
a means for forming a sealed interior envelope for a radioactive material;
a means for forming an aperture to the sealed interior envelope covered by a window material, wherein properties of the window material are selected to provide for diffusion of an isotope of helium produced by radioactive decay of the radioactive material; and
a means for selectively altering temperature properties of the window material to provide for the diffusion of the isotope of helium according to a selected diffusion rate.

20. The system of claim 19 , wherein the properties of the window material are selected to provide for the diffusion having a rate at or below a threshold rate; and
wherein the temperature properties of the window material are selectively altered to provide for the selected diffusion rate as higher than the threshold rate.

Assignees

• Lockheed Corp

Inventors

• Dempsey Brian Paul

Classifications

• B01D2325/0283

  Pore size · CPC title

• G21H1/103 Primary

  Cells provided with thermo-electric generators · CPC title

• B01D53/22

  by diffusion (manufacturing semi-permeable membranes B01D67/00; form, structure or properties of semi-permeable membranes B01D69/00; material for semi-permeable membranes B01D71/00) · CPC title

• B01D59/14

  Construction of the barrier · CPC title

• G21F5/015

  for storing radioactive sources, e.g. source carriers for irradiation units; Radioisotope containers · CPC title