Abstract
While specific, detailed economic cost of electricity calculations play a key role in day-to-day reactor fuel management tactical decisions, a higher level analysis is more useful for long term fuel cycle strategic planning. Uranium utilization, the amount of energy extracted per unit mass of natural uranium mined, is one such index. It received extensive attention in the 1970s during the U.S. Nonproliferation Alternative Systems Analysis Program (NASAP) (1) and the International Nuclear Fuel Cycle Evaluation (INFCE) (2), but much less since, following the subsequent decline in uranium cost and projected demand. Meanwhile, LWR core burnup has increased more than fifty percent, with a concurrent comparable increase in core reload enrichments and reactor intra-refueling cycle length. Moreover, programs to achieve future increases by another fifty percent and more are under current consideration. Hence reexamination of this figure of merit is in order. This is the principal goal of the present working paper, together with a parallel evaluation of the less common ratio, separative work utilization, and a new index — dollar utilization — which combines the uranium and separative work ratios.
Chapter Two introduces and validates a correlation between reload enrichment and sustainable burnup for LWRs. With this in hand and use of the linear reactivity model of core behavior (3), one can make acceptably accurate estimates of natural uranium and separative work needs for particular fuel management strategies.
In Chapter Three the three utilization indices: uranium, separative work, and dollar, are calculated and presented in the form of generic performance maps. This is followed by an exposition of how to employ these maps for reactor-specific applications.
The final chapter includes a discussion of the insight the foregoing information provides into several issues of contemporary interest — in particular the incentives for going to higher burnup and cycle length and how to do this in the most effective manner.
