Laser sintering systems and methods for remote manufacture of high density pellets containing highly radioactive elements
View Patent ↗The invention relates to remotely operated laser sintering systems and methods for manufacturing pellets containing highly radioactive elements. The highly radioactive elements can be recovered from used nuclear fuels. The systems and methods of the invention employ a feed composition including one or more highly radioactive elements and a ceramic matrix material. The feed composition is distributed in the form of a layer and sintered by directing at least one laser beam to form a pattern in the layer of the feed composition. The pattern corresponds to the shape of the pellet. Further, the sintering process can be repeated as necessary to achieve a pre-determined pellet height.
1. A remotely-operated laser sintering system to prepare a fuel pellet for use in a nuclear reactor, comprising:
a shielded enclosure;
a powder feed composition, comprising:
at least one highly radioactive element; and
a ceramic matrix material;
at least one laser positioned outside of the shielded enclosure, structured to emit a laser beam into the shielded enclosure, to operate and to control the laser beam from outside the shielded enclosure, and to sinter a layer of the powder feed composition; and
a plurality of components positioned inside of the shielded enclosure, the plurality of components comprising:
a flat surface structured to receive and hold the layer of the powder feed composition for sintering;
a hopper structured to contain the powder feed composition;
a distributer structured to substantially uniformly distribute the powder feed composition from the hopper onto the flat surface in a form of the layer;
and
a directing device structured to direct the laser beam emitted into the shielded enclosure toward the flat surface such that the laser beam contacts at least a portion of the layer of the powder feed composition, to sinter at least one pattern in the layer of the powder feed composition to form the fuel pellet, the at least one pattern corresponding to a pre-determined shape of the fuel pellet,
wherein the system is effective to produce the fuel pellet having a pre-specified height, such that if the fuel pellet is less than the pre-specified height, the fuel pellet provides a base layer and the distributer is structured to substantially uniformly distribute the powder feed composition from the hopper onto the base layer in the form of a subsequent layer, and the directing device is structured to direct the laser beam such as to contact at least a portion of the subsequent layer of the powder feed composition, to sinter the at least one pattern in the subsequent layer of the powder feed composition to form the fuel pellet.
2. The system of claim 1 , wherein the plurality of components inside of the shielded enclosure further comprises a screen to separate the pellets from unsintered powder feed composition.
3. The system of claim 1 , wherein the plurality of components inside of the shielded enclosure further comprises a powder mill to hold unsintered powder feed composition and a return line to transport the unsintered powder feed composition into the feed mechanism.
4. The system of claim 1 , wherein the plurality of components inside of the shielded enclosure further comprises a grinder to receive and grind the fuel pellet to a pre-specified diameter, a cleaner, and a fuel rod loader.
5. The system of claim 1 , wherein the directing device is selected from the group consisting of a mirror and a fiber optic cable positioned above the flat surface.
6. The system of claim 1 , wherein the enclosure has a temperature in a range of from 1000° C. to 2000° C.