Patent Number: 049903039
Section: claims

1. In a fuel element for use in a nuclear reactor which includes a fissionable material contained within a zirconium-alloy cladding tube, the improvement which comprises: a coating on the inside of the zirconium-alloy cladding tube, said coating including a boron-containing glass compound. 2. The fuel element of claim 1 in which the coating's boron-containing compound includes boron enriched to at least a 80% level of to give a desired nuclear poison level for use in the nuclear reactor. 3. The fuel element of claim 1 in which the coating's boron-containing compound includes 15Na.sub.2 O.sup..multidot. 85B.sub.2 O.sub.3 or 20Li.sub.2 O.sup..multidot. B.sub. 2O.sub.3. 4. The fuel element of claim 1 in which the zirconium-alloy includes tin in the approximate range of from 1.20 to 1.70. 5. The fuel element of claim 1 in which the coating is a residue of a sol-gel. 6. The fuel element of claim 1 in which the coating is a residue of a sol-gel that has been heated to approximately 400 .degree. C.