Module 102 The Nuclear Fuel Cycle
Highly enriched uranium was then named
"Oralloy" for "Oak Ridge Alloy," sometimes
abbreviated to "Oy." Depleted uranium was
once called depletalloy, but more commonly was
called "D-38" since it consists mostly of 238U.
These historical names are sometimes still used
within the DOE complex.
The last step in the nuclear fuel cycle is changing
the enriched uranium into an appropriate form for
fabrication. The fabrication process differs
depending on the application. For fabrication of fuel
elements, the process generally includes the
a. Uranium dioxide (UO2) is produced by reacting
UF6 with water and then with a hydroxide salt.
b. The resulting precipitate is dried to form "orange
oxide," which is reduced with hydrogen to form
c. The UO2 powder is compacted into cylindrical
pellets that are loaded into thin walled tubes
made of either stainless steel or an alloy of
zirconium called "zircalloy."