Containment cask for radioactive material

Patent metadata

Field	Value
Publication number	US-9779844-B2
Application number	US-201615172806-A
Country	US
Kind code	B2
Filing date	Jun 3, 2016
Priority date	Dec 6, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

To provide a containment cask for storage or transport of radioactive material, without employing a homogenization treatment. Pouring a molten lead between an inner shell 2 and an intermediate shell 3 to serve as a gamma ray shielding material, allowing the lead to cool, and subsequently, filling either one or both of a first void layer 9 a formed at a boundary between the inner shell 2 and the poured lead 5 a or a second void layer 9 b formed at a boundary between the intermediate shell 3 and the poured lead 5 a , using a low melting point metal 10 in a closely adhering state. To provide the cask 1 with a good heat-dissipating effect, by filling the void layers 9 a, 9 b that prevent the cask 1 from dissipating heat, with the low melting point metal 10 that has a superb thermal conductivity.

First claim

What is claimed is:

1. A containment cask for storage or transport of a radioactive material comprising:
a metallic inner shell;
a metallic intermediate shell disposed on an outer side of the inner shell;
an outer shell disposed so as to cover an outer side of the intermediate shell;
lead solidified from a molten lead poured between the inner shell and the intermediate shell to serve as a gamma ray shielding material; and
a low melting point metal filled in either one or both of (i) a first void layer formed at a boundary between the inner shell and the solidified lead or (ii) a second void layer formed at a boundary between the intermediate shell and the solidified lead.

2. A containment cask according to claim 1 , wherein the low melting point metal has a melting point lower than the melting point of lead.

3. A containment cask according to claim 1 , wherein the low melting point metal has a melting point lower than an allowable temperature of the containment cask for the radioactive material.

4. A containment cask according to claim 1 , wherein the low melting point metal is a metal or an alloy in a liquid state at a normal temperature.

5. A containment cask for storage or transport of a radioactive material comprising:
a metallic inner shell;
a metallic intermediate shell disposed on an outer side of the inner shell wherein a homogenization treatment is performed on only one of either an outer surface of the inner shell or on an inner surface of the intermediate shell;
an outer shell disposed so as to cover an outer side of the intermediate shell;
lead solidified from a molten lead poured between the inner shell and the intermediate shell to serve as a gamma ray shielding material; and
a low melting point metal filled in a void layer formed at a boundary between the solidified lead and either the outer surface of the inner shell or the inner surface of the intermediate shell, whichever surface was not homogenization treated.

6. A containment cask according to claim 5 , wherein the low melting point metal has a melting point lower than the melting point of lead.

7. A containment cask according to claim 5 , wherein the low melting point metal has a melting point lower than an allowable temperature of the containment cask for the radioactive material.

8. A containment cask according to claim 5 , wherein the low melting point metal is a metal or an alloy in a liquid state at a normal temperature.

9. A containment cask for storage or transport of a radioactive material comprising:
a metallic inner shell;
a metallic intermediate shell disposed on an outer side of the inner shell;
an outer shell disposed so as to cover an outer side of the intermediate shell;
a plurality of lead bodies, formed beforehand into any desired shape and size and inserted into a space between the inner shell and the intermediate shell to serve as a gamma ray shielding material; and
a low melting point metal filled in a void layer formed among the lead bodies.

10. A containment cask according to claim 9 , wherein the low melting point metal has a melting point lower than the melting point of lead.

11. A containment cask according to claim 9 , wherein the low melting point metal has a melting point lower than an allowable temperature of the containment cask for the radioactive material.

12. A containment cask according to claim 9 , wherein the low melting point metal is a metal or an alloy in a liquid state at a normal temperature.

13. A containment cask according to claim 9 , wherein the void layer formed among the lead bodies is filled with a good thermal conductivity oil, instead of using the low melting point metal.

Assignees

• Hitachi Shipbuilding Eng Co

Inventors

• Arai Hiroaki
• Ashida Satoshi
• Kitamura Koji
• Okada Jyun
• Ma Toki

Classifications

• G21F5/06

  Details of, or accessories to, the containers · CPC title

• G21F5/008 Primary

  Containers for fuel elements · CPC title

• G21F9/36

  by packaging; by baling · CPC title

• G21F5/10

  Heat-removal systems, e.g. using circulating fluid or cooling fins · CPC title