Unique Worthiness of SFR
A scenario relevant to countries having a limited quantity of natural uranium is presented here. Let us assume that 100 kilotons of natural uranium is available as a nuclear resource. If this resource is fueled in PHWRs and PWRs, only 3 tons can be utilized at the maximum and about 97 tons would be discharged as waste. The waste is reprocessed to separate Pu, fission products along with MA, and the remaining material is DU. If FBRs start utilizing the DU enriched appropriately with plutonium extracted from reprocessing, they can produce enough fissile material for feeding another similar FBRs after every 10 years (a typical doubling time for metal-fueled reactors). Thus, FBRs would grow, each multiplying into two in every 10 years, until the entire DU is consumed. Figure 4.4 shows the flowchart of multiplication of FBRs. With all considerations, such as high breeding ratio, high burnup, shorter doubling time, shorter delays in reprocessing and fabrication, multiple fuel recycling (closed fuel cycle), loss of DU through nonfission reactions inside the reactor, and losses external to the reactors, it takes about 100 years to utilize the entire DU, if we start with one FBR and its multiplication. And it needs more than 2000 GWe FBRs (Figure 4.5) to burn the DU.