Fully ceramic micro-encapsulated (FCM) fuel for CANDUs and other reactors
View Patent ↗A fuel pellet for a nuclear reactor includes a plurality of tristructural-isotropic fuel particles embedded in a structural silicon carbide matrix. A method of manufacturing a fuel pellet includes the steps of coating a plurality of tristructural-isotropic fuel particles with a coating slurry including silicon carbide powder to form a plurality of coated fuel particles; compacting the plurality of fuel particles; and sintering the compacted plurality of fuel particles to form the fuel pellet.
1. A fuel pellet for a nuclear reactor comprising:
a silicon carbide matrix;
a plurality of tristructural-isotropic fuel particles embedded in the silicon carbide matrix; and
two or more burnable poisons;
wherein:
the two or more burnable poisons include at least one short-acting burnable poison and at least one long-acting burnable poison;
the at least one short-acting burnable poison has a larger neutron absorption cross section compared to the at least one long-acting burnable poison; and
the at least one short-acting burnable poison includes gadolinium oxide and the at least one long-acting burnable poison includes erbium oxide.
2. The fuel pellet of claim 1 , wherein each of the tristructural-isotropic fuel particles is separated from other tristructural-isotropic fuel particles by the silicon carbide matrix.
3. The fuel pellet of claim 1 , wherein the two or more burnable poisons further include boron.
4. The fuel pellet of claim 1 , further comprising:
fabricated coated particles that include the two or more burnable poisons; and
wherein the fabricated coated particles are mixed with the tristructural-isotropic fuel particles in the silicon carbide matrix.
5. The fuel pellet of claim 4 , wherein the fabricated coated particles are bi-structural isotropic particles.
6. The fuel pellet of claim 4 , wherein at least one of the fabricated coated particles includes boron.
7. The fuel pellet of claim 1 , wherein the two or more burnable poisons are contained in the silicon carbide matrix.
8. The fuel pellet of claim 1 , wherein:
each of the tri-structural isotropic fuel particles include:
a fuel kernel; and
four layers of three isotropic materials; and
the four layers of three isotropic materials coat the fuel kernel.
9. The fuel pellet of claim 8 , wherein:
the fuel kernel includes uranium nitride (UN), uranium carbide (UC), uranium oxicarbide (UCO), or uranium dioxide (UO2); and
the four layers of three isotropic materials include a porous buffer layer made of carbon, an inner layer of pyrolytic carbon, a ceramic layer, and an outer layer of pyrolytic carbon.
10. The fuel pellet of claim 9 , wherein the ceramic layer of each of the tri-structural isotropic fuel particles is formed of silicon carbide.
11. The fuel pellet of claim 10 , wherein the ceramic layer formed of silicon carbide of each of the tri-structural isotropic fuel particles includes at least one of the two or more burnable poisons.