Nuclear Science and Engineering / Volume 154 / Number 1 / September 2006 / Pages 1-27
Fuel cycles employing recycling of actinides in the thermal COmbined NonFertile and UO2 (CONFU) fuel light water reactor (LWR) or fast Actinide Burner Reactor (ABR) plus standard LWRs are compared to the once-through LWR fuel cycle under the assumption of moderately growing worldwide demand for nuclear energy until 2050. The transuranic elements (TRUs) in temporary storage, the TRUs sent to permanent repositories, and the system cost are taken as key figures of merit. The CONFU strategy (standard LWRs plus CONFU LWRs) is shown to reduce the TRU accumulation by ~34%, relative to the reference once-through fuel cycle strategy, while the ABR strategy (standard LWRs plus ABRs) exhibits a smaller reduction (by 9%). The CONFU fuel assembly was designed to stabilize the TRU inventory in LWRs with zero TRU incineration rate. Nevertheless, deployment of this concept limits the ex-core TRU inventory. The actinide production in the CONFUs is also reduced by virtue of the loading of 20% of the core with nonfertile actinide fuel pins. On the other hand, the ABR burner, designed to consume the actinides in fertile-free fuel (FFF), has a large net TRU incineration rate and therefore a potential for faster TRU depletion from storage facilities. However, it suffers from a likely delay of deployment, compared to the CONFU, due to the need for more extensive research and development effort. Even when extending the time frame to 100 yr, the fast ABR cannot overcome the disadvantage of its late deployment compared to the thermal CONFU. In part, this is due to the fact that the ABR has a lower TRU destruction rate per gigawatt(electric) than the CONFU because of its higher thermal efficiency.
Both strategies greatly reduce the total TRU mass destined to the permanent repositories, thus alleviating the burden of licensing a large number of such repositories, and the risk from deliberate or accidental excavation of TRUs from the repositories. The implementation of these strategies requires development of FFF pins for both CONFU cores and fast reactors.
Economic analyses show that both closed fuel cycles are more expensive than the reference once-through scheme. The total busbar cost of electricity production is expected to be 4 to 5 mills/kWh(electric) (~10 to 12%) larger than the once-through cycle case if the spent-fuel separation is paid for by electricity sales from the separated fuel. The cost impact will be much less if the necessary funds are collected while the original fuel is irradiated.