Spent Nuclear Fuel Storage Scheme

• US 20140126682A1
• Filed: 11/04/2013
• Published: 05/08/2014
• Est. Priority Date: 11/06/2012
• Status: Active Grant

• Current Assignee: Russell Goff
• Original Assignee: Russell Goff
• Inventors: Goff, Russell
• Granted Patent: US 9,937,273 B2
• Time in Patent Office: Days
• US Class Current: 376/272
• CPC Class Codes: A61L 2/081 Gamma radiation
• CPC Class Codes: G21C 19/32 Apparatus for removing radioactive objects or materials from the reactor discharge area, e.g. to a storage place; Apparatus for handling radioactive objects or materials within a storage place or removing them therefrom disposal of waste material G21F9/00
• CPC Class Codes: G21F 7/015 Room atmosphere, temperature or pressure control devices
• CPC Class Codes: G21F 7/06 Structural combination with remotely-controlled apparatus, e.g. with manipulators
• CPC Class Codes: Y02E 30/30 Nuclear fission reactors

Abstract

Methods, apparatuses, and systems for the storage of spent nuclear fuel (SNF) such that a single facility can serve as both a SNF storage facility and a gamma ray irradiation facility are disclosed. In one embodiment, the SNF is encapsulated inside of a container. The SNF bearing container prevents the escape of fission products into the environment but allows the escape of gamma rays from the container. In this embodiment, several of these containers are evenly spaced throughout a room within a fortified facility and a conveyor system transports products through the room such that gamma rays emitted by the SNF deposit a desired amount of energy into the products. A passive heat removal system is formed by the coupling of the SNF bearing container to a thermal conduction element such that the SNF remains sufficiently cool even when the SNF is generating large heat loads.

Claims

1. An apparatus comprising;

a thin barrier configured to be disposed between a portion of spent nuclear fuel (SNF) and an external area containing materials meant to be irradiated by gamma rays, where the thin barrier is configured to substantially prevent the release of radioisotopes found in the SNF while also being configured to allow the release of a substantially large portion of the gamma rays produced by the SNF into the external area.

2. An apparatus according to claim 1 comprising:

a coolant disposed proximate to the thin barrier, the coolant being configured to substantially minimize the attenuation, in at least one direction, of gamma rays produced by the SNF; and

a thermally conductive element in thermal contact with the thin barrier, the thermally conductive element being configured to transfer at least some of the heat produced by the SNF to a heat sink.

3. An apparatus according to claim 2 wherein the thin barrier comprises a container, wherein the container further comprises a void for receiving the SNF.

4. An apparatus according to claim 2 comprising;

a thin open ended container;

a liquid or gaseous coolant contained inside, above, and/or below the thin open ended container configured to substantially minimize the attenuation of gamma rays produced by the SNF in the length of the open ended container between the SNF and an external area containing materials meant to be irradiated while preventing the radioisotopes that are creating the gamma rays from escaping into the external area containing materials meant to be irradiated;

5. An apparatus according to claim 2 wherein the thermal conductive element penetrates through a shielded transport container and is configured to remove heat from the SNF during transportation of the SNF

6. A system, comprising;

An SNF storage facility including a top level, an irradiation room level and a bottom level;

a plurality of spent nuclear fuel (SNF) bearing containers, the SNF bearing containers being configured to contain SNF;

aligned penetrations formed in each level such that the SNF bearing containers may be maneuvered between the various levels; and

a plurality of thermal conduction elements, at least one of the plurality of thermal conduction elements being in thermal contact with at least one SNF bearing container such that at least one SNF bearing container and at least one thermal conduction element may be maneuvered as a single unit through the levels of the SNF storage facility.

7. The system according to claim 6, wherein at least one of the thermally conductive elements is sized sufficiently in length to traverse the distance between the top level of the SNF storage facility and the bottom level of the SNF storage facility such that a substantially highly thermally conductive path from the SNF bearing container to the top level of the SNF storage facility is formed.

8. The system according to claim 6, wherein at least one thermally conductive element that is in thermal contact with an SNF bearing container, and wherein the thermally conductive element is visibly distinct from the SNF bearing container such that visible indication is given to workers in the irradiation room level of the SNF storage facility as to whether the SNF bearing container is still present at the irradiation room level of the SNF storage facility.

9. The system according to claim 6, wherein at least one thermally conductive element is in thermal contact with an SNF bearing container, and wherein the thermally conductive element protrudes into the top level of the SNF storage facility while the SNF bearing container is located within the irradiation room level of the SNF storage facility such that the change in the length of the thermal conduction element that is protruding through the top level of the SNF storage facility gives a visible indication of the location of the SNF bearing container within the SNF storage facility

10. The system according to claim 6, wherein the plurality of SNF bearing containers are arranged in the SNF storage facility such that radiation fields of varying intensity and energy spectrum are created within the facility to provide different dose rate options for products depending on what portion of the irradiation room the products are carried through.

11. The system according to claim 6, further comprising:

a transportation mechanism within the SNF storage facility, the transportation mechanism being configured to transport the SNF bearing containers from the irradiation room level to the bottom level of the SNF storage facility such that the radiation levels in the irradiation room level of the SNF storage facility can be substantially lowered by lowering the SNF bearing containers into the bottom level of the facility

12. The system according to claim 6, wherein at least one thermal conduction element includes a bulge configured such that as the SNF bearing container is lowered into the bottom level of the SNF storage facility the bulge collides with the area near its associated penetration between the irradiation room level and the top level of the SNF storage facility and prevents the SNF bearing container from being lowered any further and suspends the SNF bearing container above the bottom of the penetration in the bottom level of the SNF storage facility and prevents the SNF bearing container from colliding with the bottom of the penetration during a free fall.

13. The system according to claim 6, wherein at least one thermal conduction element includes a bulge configured to shield gamma rays that would otherwise stream out through the top of the thermal conduction element and thereby prevent the creation of unwanted high radiation areas.

14. A method of managing spent nuclear fuel, comprising;

placing spent nuclear fuel (SNF) into a plurality of SNF bearing containers, the SNF bearing containers being configured to allow the release of gamma radiation and prevent the release of the radioisotopes which produce the gamma radiation;

placing the SNF bearing containers in multiple locations within a SNF storage facility such that the SNF bearing containers produce substantially intense radiation levels inside of the SNF storage facility.

15. The method of claim 14, wherein the SNF bearing containers are separated by at least the distance required to prevent criticality accidents, and are separated by a sufficient distance from one another such that products may be maneuvered between the SNF bearing containers to receive a substantially uniform dose of gamma rays in a single pass through the facility.

16. A method according to claim 14 comprising;

cooling SNF during transportation of the SNF to the SNF storage facility wherein the SNF is located inside of a shielded transport container;

thermal conduction elements are able to come into direct thermal contact with the SNF through penetrations in the shielded transport container;

thermal conduction elements form a direct thermal conduction pathway between the SNF and the environment such that heat from the SNF is dissipated to the environment without the release of radioisotopes to the environment.

17. The method of claim 14, wherein the SNF bearing containers are arranged within the facility such that criticality accidents are prevented without the need for neutron poisons by separating the individual SNF elements far enough away from each other to create a high neutron leakage geometry such that the fission chain reaction does not become self-sustaining.

18. A method according to claim 14, further comprising coupling the SNF bearing containers to thermally conductive elements which reject heat to a heat sink such that SNF may be maintained below a particular temperature threshold.

19. The method according to claim 14, further comprising encapsulating SNF rods or SNF assemblies in the SNF bearing containers such that sufficient gamma radiation is emitted from the SNF bearing containers.

20. The method of claim 14, further comprising:

placing a SNF rod or SNF assembly into an SNF bearing container;

filling said container with a fill material;

sealing said container, thus encapsulating the SNF; and

employing this encapsulated SNF as a source of gamma rays within the SNF storage facility.