PPT Slide

Many materials are non-stoichiometric. Uranium dioxide

is especially so. So, UO2+x is possible, the value of x

depending on the oxygen pressure in the atmosphere.

DU ? x2

It is found that the uranium dioxide is able to exchange

oxygen with the atmosphere. When the oxygen pressure

in the atmosphere is high, oxygen enters the material.

When the pressure is low, oxygen leaves the material

½ O2 (g) = Oi= + 2 h•

O2 (g) = VU”” + 4 h•

for UO2+x

for U1-xO2