Study on the influence of the fuel burn-up on the generation cost for FR cycle

Some studies about the relation between burn-up and economic in the FR cycle have been performed until now. The results of these studies indicate that the core fuel assemblies with average burn-up of 150∼200GWd/t is proper for target value from the economic viewpoint. The phase-I of JNC's Feasibility Studies on Commercialized Fast Reactor Cycle System (the F/S)' started from 1999. In the F/S study, reactor construction cost, reprocessing cost and fabrication cost of FR cycle were revised largely and importance of improvement of the average burn-up for whole fuel assemblies including blanket fuels was confirmed. Accordingly, based on the newest FR plant and core designs in the F/S study, the influence of the fuel burn-up on the generation cost was examined on the assumption that core diameter, CDF (Cumulative Damage Fraction) condition and so on are constant. The results may be summarized as follows. - As for the constant breeding ratio case (about 1.1), the generation cost becomes the minimum at around 150GWd/t as average burn-up for core fuel assemblies (or at around 90GWd/t of average burn-up for whole fuel assemblies). It is caused by both effects of decrease of fuel mass flow, and increase of fuel cycle unit cost and decrease of load factor, as fuel burn-up rises. - When the breeding ratio increases (addition of axial blanket fuels), the generation cost rises because average burn-up for the whole fuel assemblies decreases. (author)