Koji Nagano

Systems analysis of spent fuel management in Japan, (II). Methodologies for economic analyses of spent fuel storage

Analytical methods for economic analyses of spent fuel storage are categorized in three layers; (1) static engineering-economic cost estimates, (2) dynamic strategy analyses, and (3) specific project financing assessments. After describing recent legal and institutional evolution in spent fuel management and storage in Japan, the report summarizes each of the three methods with numerical examples of applications. As a conclusion, the author maintains that users should choose the most suitable type of method or calculating tool in accordance with their specific purposes. General guidelines of choosing methodologies are elaborated as the conclusion.

Global energy strategies to control future carbon dioxide emissions

We analyse long-term energy prospects from the point of view of future carbon dioxide emissions and constraints imposed by possible changes in the global climate. The approach is based on scenario simulations of technical, economic, social, and cultural changes which determine future energy use and their environmental impacts to the middle of the next century. For this purpose, two scenarios have been formulated: one with changes in society, the economic system, and the energy sector that follow the dynamic-as-usual pattern and the other with enhanced energy-efficiency improvements and conservation efforts. For each scenario, three different cases have been investigated reflecting possible situations on the energy supply-side. The consequences of various policy options in energy supply and demand have been evaluated to understand the efficacy of different measures in approaching a global greenhouse-gas-abatement energy policy.

Systems analysis of spent fuel management in Japan, (I). Projection of material balances and storage needs

Spent fuel accumulation in the future and its appropriate management strategy for Japan is analyzed by “SFTRACE” (Spent Fuel Storage, TRAnsportation and Cost Evaluation System) is introduced, which consists of 3 sub-models; (1) the economic cost data base for spent fuel storage technologies, (2) the long-range simulation of reactor mix and plutonium (Pu) utilization, and (3) the detailed simulation of spent fuel management strategies. The long-range simulation sub-model presents a macroscopic overview on how much amount of spent fuel stockpile should be addressed nationwide at a certain time point. A preliminary calculation shows that the spent fuel storage needs in Japan to the year 2050 will vary significantly, from a decrease towards zero or a continuous increase up to 20,000–25,000 tHM. The sub-model for spent fuel management simulation is the tool to demonstrate nationwide strategies to deal with spent fuel accumulation, either at each power station site or a number of centralized facilities in the given time horizon, with associated needs of transportation. An illustrative analysis shows trade-off relationship among factors involved in spent fuel management strategies, such as between “away from reactor (AFR)” storage capacity and overall transportation requirements, which vividly demonstrates the usefulness of the integrated analytic tool.