[en] The fracture toughness of A508 steel was measured at a temperature slightly below RTsub(NDT). Several methods of data analysis were used, and the stored-elastic-energy approach of Seidl was found to provide the lowest and most reproducible Ksub(Ic) values. Although this method has theoretical drawbacks, it is argued that its results are consistent with current understanding of the relations between fracture toughness and microstructure. (author)