# US 2018/0025800 A1 · Container and system for handling damaged nuclear fuel, and method of making the same

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- Number: US 2018/0025800 A1
- Document ID: US20180025800A1
- Status: Published application
- Kind: A1
- Application number: 15/689,571
- Filed: 2017-08-29
- Published: 2018-01-25
- Earliest claimed: 2011-08-19
- Assignees: Holtec International
- Applicants: Holtec International
- Inventors: Krishna P. Singh
- Web page: https://patentgrep.com/patent/US20180025800A1

## CPC

- G21F 5/008: Containers for fuel elements
- B23K 2101/12: Vessels
- B23K 2103/172: {wherein at least one of the layers is non-metallic}
- G21C 19/26: Arrangements for removing jammed or damaged fuel elements or control elements; Arrangements for moving broken parts thereof
- G21F 5/012: Fuel element racks in the containers
- G21F: PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR (radiation protection by pharmaceutical means A61K8/00, A61Q17/04; in cosmonautic vehicles B64G1/54; combined with a reactor G21C11/00; combined with X-ray tubes H01J35/16; combined with X-ray apparatus H05G1/02)
- B23K: SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- G21C: NUCLEAR REACTORS (fusion reactors, hybrid fission-fusion reactors G21B; nuclear explosives G21J)

## Abstract

A container and system for handling damaged nuclear fuel, and a method of making the same. In one embodiment, the invention is a damaged fuel container having a specially designed top cap that can be detachably coupled to the elongated tubular wall by simply translating the top cap into proper position within the elongated tubular wall, wherein biased locking elements automatically lock the top cap to the elongated tubular wall. In another embodiment, the vent screens of the damaged fuel container are integrally formed rather than being separate components. In still other embodiments, the lower vent screens are arranged on an upstanding portion of the damaged fuel container. In an even further embodiment, the elongated tubular wall is formed by an extrusion process.

## Claims

### Claim 1

A method of forming an elongated tubular container for receiving damaged nuclear fuel, the method comprising:
a) extruding, from a material comprising a metal and a neutron absorber, an elongated tubular wall having a container cavity;
b) forming, from a material comprising a metal that is metallurgically compatible with the metal of the elongated tubular wall, a bottom cap comprising a first screen having a plurality of openings; and
c) autogenously welding the bottom cap to a bottom end of the elongated tubular wall, the plurality of openings of the first screen forming vent passageways to a bottom of the container cavity.

### Claim 2 (depends on 1)

The method according to claim 1 wherein step b) further comprises:
b-1) casting a body of the bottom cap; and
b-2) integrally forming the plurality of openings into the body of the bottom cap to form the first screen.

### Claim 3 (depends on 2)

The method according to claim 2 wherein the plurality of openings are integrally formed by laser cutting the plurality of openings into the body of the bottom cap.

### Claim 4 (depends on 1)

The method according to claim 1 wherein the elongated tubular wall is formed of a metal matrix composite having neutron absorbing particulate reinforcement.

### Claim 5 (depends on 4)

The method according to claim 4 wherein the metal matrix composite having neutron absorbing particulate reinforcement is a boron carbide aluminum matrix composite material.

### Claim 6 (depends on 1)

The method according to claim 1 wherein the bottom cap is formed of aluminum.

### Claim 7 (depends on 1)

The method according to claim 1 wherein step c) further comprises:
c-1) butt welding the bottom cap to the bottom end of the elongated tubular wall to produce a weld junction that is smooth with an outer surface of the elongated tubular wall.

### Claim 8 (depends on 1)

The method according to claim 1 wherein the container cavity of the elongated tubular wall resulting from step a) has a substantially constant transverse cross-section.

### Claim 9 (depends on 8)

The method according to claim 8 further comprises:
expanding a portion of the transverse cross-section of the container cavity along a top portion of the elongated tubular wall.

### Claim 10 (depends on 9)

The method according to claim 9 wherein the expanded portion of the transverse cross-section of the container cavity tapers moving away from a top edge of the elongated tubular wall.

### Claim 11 (depends on 1)

The method according to claim 1 further comprising:
d) forming a top cap having a second screen comprising a plurality of openings; and
e) detachably coupling the top cap to the elongated tubular wall, the plurality of openings of the first cap forming vent passageways into a top of the container cavity.

### Claim 12 (depends on 11)

The method according to claim 11 wherein step e comprises:
e-1) sliding the top cap into an open top end of the container cavity, wherein locking elements of the top cap that are normally biased into an extended state are forced into a retracted state due to contact with the elongated tubular wall during said sliding; and
e-2) upon the locking elements of the top cap becoming aligned with locking apertures of the elongated tubular container, the locking elements automatically returning to the extended state such that the locking elements protrude into the locking apertures.

### Claim 13

A system for storing and/or transporting nuclear fuel comprising:
a vessel comprising defining a vessel cavity and extending along a vessel axis;
a fuel basket positioned within the vessel cavity, the fuel basket comprising a grid forming a plurality of elongated cells, each of the cells extending along a cell axis that is substantially parallel to the vessel axis; and
at least one elongated tubular container comprising a container cavity containing damaged nuclear fuel positioned within one of the cells, the elongated tubular container comprising:
an extruded tubular wall forming a container cavity about a container axis, the extruded tubular wall formed of a metal matrix composite having neutron absorbing particulate reinforcement;
a bottom cap coupled to a bottom end of the extruded tubular wall;
a top cap detachably coupled to a top end of the extruded tubular wall;
a first screen comprising a plurality of openings that define lower vent passageways into a bottom of the container cavity; and
a second screen comprising a plurality of openings that define upper vent passageways into a top of the container cavity.

### Claim 14 (depends on 13)

The system according to claim 13 wherein a top portion of the extruded tubular wall comprises locking apertures, and the top cap comprises locking elements that are alterable between a retracted state and an extended state, the locking elements biased into the extended state, and wherein the top cap is detachably coupled to the extruded tubular wall when the locking elements are in the extended state and protrude into the locking apertures.

### Claim 15 (depends on 14)

The system according to claim 14 wherein contact between the extruded tubular wall and the locking elements forces the locking elements into the retracted state during insertion of the top cap into the container cavity until the locking elements become aligned with the locking apertures.

### Claim 16 (depends on 14)

The system according to claim 14 wherein the bottom cap comprises the first screen and the top cap comprises the second screen.

### Claim 17 (depends on 16)

The system according to claim 16 wherein the first screen is integrally formed into a body of the bottom cap and the second screen is integrally formed into a body of the top cap.

### Claim 18 (depends on 13)

The system according to claim 13 wherein the bottom cap comprises a floor plate that forms a floor of the container cavity and an oblique wall plate extending upward from a perimeter of the floor plate, the oblique wall plate coupled to the bottom end of the extruded tubular wall, the first screen located on the oblique wall plate of the bottom cap.

### Claim 19 (depends on 13)

The system according to claim 13 further comprising a floor of the container cavity, and wherein at least one of the plurality of openings of the first screen is located an axial distance above the floor of the container cavity.

### Claim 20 (depends on 15)

The system according to claim 15, wherein the locking elements are spring biased latearlly outward towards the extended state.