FAST REACTOR TRANSMUTATION PERFORMANCE AND CONVERSION RATIO EFFECTS

摘要

The sometimes highly complex physics analyses performed to evaluate transmutation systems often make interpretation of the results challenging. There are a number of underlying relationships that have been developed to understand the general performance of transmutation systems. Those relationships and their implications are discussed. The assumed constraints imposed upon the design often dictate the performance. Key constraints and their impacts are analyzed. The fuel residence time dictates much of the key performance parameters for a given conversion ratio, such as burnup. The TRU consumption rate is independent of the burnup and is determined solely by the conversion ratio as is the uranium resource utilization. However, minimizing transuranics in the waste requires minimizing the transuranics sent to reprocessing, which is fairly independent of conversion ratio, but is a strong function of fuel residence time. The fraction of energy generated by fast reactors in a nuclear park can be evaluated in several ways. Integrated over time, it is determined by the conversion ratio. However at a given time for a dynamic system, it is a function of many additional variables. A simple approximation is provided to evaluate the dynamic equilibrium state of single-tier closed fuel cycle. The large amount of transuranic material required to deploy new fast reactors results in a greatly reduced fraction of the energy generated by fast reactors in a growing nuclear enterprise compared to the ultimate fraction of energy that will be generated by the fast reactors if the fuel cycle is run to completion.