An overview is given of the methodology followed in France to evaluate the risk of brittle fracture in transport casks. Various aspects are considered in this evaluation. First; the material characterisation: effect of strain rate and temperature on tensile properties and toughness. Secondly: evaluation of applied stress under dynamic loading and criteria to define worst cases (time, distribution). Thirdly: the global validation is presented to demonstrate that the whole methodology is conservative; consideration of representative analytical cases where initiation is obtained under controlled conditions. Results are presented concerning cast ductile iron and carbon steel materials. (author).