Fracture Predictions in Zircaloy Fuel Cladding

Predictions of the maximum initial allowable temperature required to achieve a 40-year life in dry storage are made for Zircaloy clad spent fuel. Maximum initial temperatures of 360 to 405°C for irradiated spent fuel cladding (wet pool storage) are predicted.

The technique utilized in this work is based on the deformation and fracture map methodology. Maps are presented for temperatures between 50 and 850°C and stresses between 5 and 500 MPa. These maps are then combined with both the known temperature history (an exponentially decaying one) of Zircaloy fuel cladding in dry storage and a life fracture rule to predict the rupture life of the cladding in dry storage.

Predictions of the deformation and fracture map methodology are shown to be in good agreement with constant stress-constant temperature data.