AbstractA detailed energy flow diagram for indirect drive ICF was elaborated. Using driver pulse energy as input, this diagram undergoes various energy processes of conversion, absorption, re-emission and transfer, until the thermonuclear energy delivered by target fusion is reached as output. Each process was identified with an energetic parameter (efficiency or gain). Starting from this diagram it was possible to analyse the influence of each energetic parameter on the energetic balance of ICF power plant. In this paper special attention was put on the influence of target design (materials and dimensions) on the transfer efficiency and on capsule illumination uniformity. The analysis led to the evaluation of optimal target materials and dimensions to achieve a positive energetic balance of an ICF power plant.