Thermochemical Behavior of Gallium in Weapons-Material-Derived Mixed-Oxide Light Water Reactor (LWR) Fuel

The use of weapons‐derived plutonium in light water reactor (LWR) fuel must consider the effects of up to 1 mass% of gallium that is used in weapons plutonium alloy. The potential effects of this residual gallium have been examined for 5% PuO2‐95% UO2 from a thermochemical standpoint. The state and effect of gallium in the fuel are predicted, based on the oxygen potential of the fuel and the effects of burn‐up. The possibility of vapor‐phase transport of gallium to the fuel clad and potential interaction with the clad also is assessed.