| Summary: | Thesis (S.M.)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 2005. === This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. === Page 251 blank. === Includes bibliographical references (p. 236-239). === The deployment of fuel recycling through either CONFU (COmbined Non-Fertile and UO2 fuel) thermal watercooled reactors (LWRs) or fast ABR (Actinide Burner Reactor) reactors is compared to the Once-Through LWR reactor system in terms of accumulation of actinides over the next 100 years under the assumption of a growing worldwide demand for nuclear energy. It is assumed that the growth rate is about 2.1% per year up to 2053, with alternative scenarios after that date. The transuranics (TRU) stored in temporary repositories, the TRU sent to permanent repositories, the system cost and a vulnerability index toward proliferation are calculated by the CAFCA code and taken as key figures of merit. Deployment of the ABRs is assumed to occur later (2028) than the CONFU LWRs (2015), whose technology requires less extensive additional R&D. Through 2050 the CONFU strategy performs better than the ABR strategy. The CONFU LWRs in our model yield zero net TRU incineration while the ABRs have a net consumption of TRU. Compared to the Once-Through strategy, by 2050 the CONFU (respectively ABR) strategy reduces by about 22% (respectively 16%) the total inventory of TRU in the system. This reduction corresponds to the TRU production being avoided by CONFU LWRs or being incinerated in ABRs compared to the TRU produced in the traditional LWRs used in the Once-Through strategy. === (cont.) The net consumption of TRU in ABRs makes the ABR strategy more attractive in a longer term. By 2100, the ABR (respectively CONFU) strategy would have reduced the worldwide TRU inventory by 75% (respectively 58%) compared to the Once-Through case. The three strategies are also discussed with regard to uranium ore availability, repository need, and processing plants need. It is interesting to note that with either recycling strategies the total capacity for separation of spent UO2 constituents need only be four to five times the existing capacity today. Furthermore, only one TRU recycling plant from fertile-free fuel would be needed at a capacity of 250 MTHM/year up to 2050. The economic analysis shows that both closed fuel cycles are more expensive than the reference Once-Through scheme. The total cost of electricity production is expected to be 5 mills/kWhe, or about 15%, larger than the Once-Through cycle case, if the spent fuel separation is paid off by the electricity sales from the resulting fuel. The timing of collection of fuel cycle costs significantly affects the cost of electricity. Paying for fuel separation by the sales of the electricity producing the spent fuel to be reprocessed later has a smaller effect on the cost of electricity in the advanced fuel cycles (between 1 or 2 mills/kWhe or between 3 and 6%) compared to the cost of electricity in the Once-Through strategy. === (cont.) From a policy point of view, an index of vulnerability toward proliferation is defined and gives an advantage to the advanced fuel cycles. The large amount of heavy metal in the repository and the long life time of this repository penalize the Once-Through strategy. However the results are sensitive to the accessibility factor assigned to the repository which is, as all accessibility factors, a subjective value that is not precisely defined. Moreover, worldwide cooperation to implement the two advanced strategies and the challenges this implementation could face are discussed. The use of a single behaviour mode throughout the world implies an unlikely perfect cooperation between countries that do not have the same capabilities or incentives to choose among the advanced fuel cycle strategies. === by Thomas Boscher. === S.M.
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