Evaluation of economical efficiency in adoption of high burnup for LWR fuel

Based on the core model of PWRs, the plan of fuel exchange in 12 cases of the equilibrium cycle was set up in the ranges of extracted burnup from 30,000 to 60,000 MWd/t and operation cycle from 9 to 18 months including 3 months shutdown period during the operation cycle, and the cost of fuel cycle and the cost of power generation were calculated by the simplified model for evaluating economic efficiency. The cost of fuel cycle lowered as the extracted burnup was raised within the investigated range. Besides, when the operation cycle was extended while the extracted burnup was maintained invariably, the cost of fuel cycle rose, but the rate of rise was relaxed by raising the burnup. When the breakdown of the cost of fuel cycle was examined, the cost of uranium enrichment rose by adopting high burnup, and the cost of natural uranium concentrate leveled off, while it was found that the large decrease of the cost of fuel forming and fabrication and of the cost of back end service brought the cost of fuel cycle down. Also the cost of power generation lowered as burnup was raised. Besides, by the extension of operation cycle, the capacity ratio of power stations rose, and the fixed cost was largely saved, and this amount of saving exceeded the increment of fuel cycle cost, therefore, the cost of power generation was lowered. (Kako, I.)