On the basis of an American tender for alSO megawatt atomic power plant, the cost factors of nuclear energy are being discussed, i. e.: 1. plant cost including site and site development, cooling water, interest during construction, 2. capital cost including taxes, normal and nuclear insurance, 3. annual efficiency, 4. load factor, 5. interest on fuel inventory, 6. operating costs including repairs, 7. burnup. It is shown, that all cost factors of the tender have been calculated too low and that the guarantees are insufficient. The conclusion to be drawn is that electric energy from alSO megawatt nuclear plant nowadays is not competitive with electric power from coal, without having taken into ac- count standstill costs caused through extraordinary events in the reactor. Resume A l'aide d'un devis americain relatif a une centrale atomique de 150 MW, les elements les plus importants qui determinent les frais de revient ont ete discutes un a un, a savoir: 1. Les frais de premier etablissement, dans lesquels doivent etre compris les depenses non en relation directe avec les fournitures proprement dites, il s'agit de l'acquisition et de l'amenagement du terrain abatir, des interets intercalaires etc., 2. Les charges du capital y compris les imp8ts, les frais pour assurances contre risques normaux et nucIeaires ainsi que les frais d'administration, Resurne 19 3. Le rendement annuel, 4. L'utilisation annuelle, 5. Les pertes d'inter&ts resultant de la modalite de paiment du combustible nucIeaire, 6.