Patent Number: 
Section: claims

1. A fuel assembly comprising a plurality of fuel rods, each fuel rod containing a plurality of nuclear fuel pellets not requiring coatings, wherein at least one fuel pellet in more than 50% of said fuel rods in said fuel assembly comprises a sintered admixture consisting of UO2 and ZrB2. 2. The fuel assembly of claim 1, wherein said ZrB2 is present in said fuel pellet in an amount of about 5 ppm to about 5 wt %, based on the total amount of fuel in said fuel pellet. 3. The fuel assembly of claim 2, wherein boron of said ZrB2 is present in said fuel pellet in an amount of about 10 ppm to about 20,000 ppm, based on the total amount of fuel in said fuel pellet. 4. The fuel assembly of claim 1, wherein said ZrB2 in said at least one fuel pellet comprises enriched boron. 5. The fuel assembly of claim 4, wherein said enriched boron is enriched to a content of 10B greater than natural boron. 6. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 60% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2. 7. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 70% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 8. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 80% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 9. The fuel assembly of claim 1, wherein at least one fuel pellet in at least 90% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 10. The fuel assembly of claim 1, wherein at least one fuel pellet in more than 50% and less than 90% of said fuel rods in said fuel assembly comprises a sintered admixture of UO2 and ZrB2. 11. The fuel assembly of claim 3, wherein the boron is 600 to 20000 ppm of the admixture. 12. A boiling water reactor having a fuel assembly, the fuel assembly comprising a plurality of fuel rods, each fuel rod containing a plurality of nuclear fuel pellets not requiring coatings, wherein at least one fuel pellet in more than 50% of said fuel rods in said fuel assembly comprises a sintered admixture consisting of UO2 and ZrB2.