URANIUM. 1. THE CASE FOR ENRICHED URANIUM 2. THE CASE FOR NATURAL URANIUM 3. URANIUM ALLOYS AND DISPERSIONS 4. URANIUMOXIDE EXPERIENCE

The advantages of the use of enriched uranium, natural uranium, uranium alloys and dispersions, and uranium oxides are discussed in foar separate sections. The principal reason for the use of enriched uranium is the consistent indication that this fuel will cost less. Its main disadvantages are the higher basic fuel cost and the necessity for isotope separation plants and chemical reprocessing iacilities. The chief advantage of natural uranium fuel is that reactors using it are operable on a universally available fuel. The disadvantages are the cost of the heavy water and the fact that heavy water reactors tend to be larger in size. As a nuclear material, unalloyed uranium has the disadvantage of exensive anisotropic dimensional changes and surface roughening under irradiation. Alloys which are highly effective when combined with suitable heat treatment and/or fabrication techniques are described Uranium oxide, because of its physical properties and excellent resistance to radiation damage, can be used in reactors operating at low, intermediate, and high temperatures. UO/sub 2/ fabrication, physical properties, radiation damage, and fuel-element fabrication are discussed. (J.S.R.)