[en] A doubling time less than or equal to 15 years is possible with the carbide type fuel element in numerous technological configurations. From these results the two references were selected which seemed best suited to French circumstances. In both cases the most critical manufacturing parameter is smear density which must be kept to the highest possible value; swelling and mechanical interaction studies must therefore proceed with this objective in mind. On the other hand, one must not forget that the results obtained in the (most likely optimistic) hypotheses of a 1 year out-of-pile time may need to be questioned in the case of longer out-of-pile times. Nevertheless, at the present moment, the problem of out-of-pile time is not solved for oxide type fuel elements any more than for carbide type elements. Therefore, arbitrary values for this parameter must be chosen for computations. It is important to note that carbide type fuel elements always compare favourably with oxide type fuel elements when out-of-pile times are approximately the same for both fuels. 11 figures