Failure and ductile to brittle transition of oxidized zirconium

A new test procedure has been developed for the characterization of the change of mechanical properties of Zr alloys during LOCA accidents. The mechanical conditions for the failure of fuel cladding during quenching without additional mechanical loads has been estimated in terms of specific energy at failure (E < 1 J/m). Correlations have been produced to describe the failure of E110 and Zircaloy 4 cladding at zero mechanical loads during quench after a LOCA event. It was pointed out that very long oxidation is needed to arrive from ductile to brittle transition to the failure at zero mechanical load (about 15 times longer than the oxidation time to reach ductile to brittle transition) and the fuel failure in the intermediate region depends on the mechanical loads associated with quench