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Combining Thorium with Burnable Poison for Reactivity Control of a Very Long Cycle BWR

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Show simple item record Inoue, Y. Pilat, Edward E. Xu, Z. Kazimi, Mujid S.
dc.contributor.other Massachusetts Institute of Technology. Nuclear Fuel Cycle Program en_US 2012-12-03T20:22:19Z 2012-12-03T20:22:19Z 2004-06
dc.description.abstract The effect of utilizing thorium together with gadolinium, erbium, or boron burnable absorber in BWR fuel assemblies for very long cycle is investigated. Nuclear characteristics such as reactivity and power distributions are evaluated using CASMO-4. Without thorium, the results show that gadolinium enriched in Gd-157 has the lowest reactivity swing throughout the cycle. However, the local peaking factor (LPF) in the assembly at beginning-of-life (BOL) is high. The erbium case shows more reactivity swing but the LPF is lowest of all three cases. B4C case has the highest reactivity at BOL which would have to be suppressed by control rods. The most important advantage of B4C over others is the saving of uranium inventory needed to achieve the target exposure of 15 effective full power years (EFPY). Further analysis for transient conditions must be performed to ensure meeting all transient limits. Use of thorium in place of some burnable poison makes it possible to save some uranium enrichment while achieving equivalent discharge burnup to the case without thorium, but only by about 1 %. The benefit is small because almost the same amount of burnable poison is always required for suppressing excess reactivity throughout the cycle. Since Th-232 functions more like U-238 than burnable poison, this limits the allowed thorium to extend discharge burnup. Since all fuel assembly designs in this study have the same target exposure of 15EFPY, the economic performance of each design can be compared based on the amount and enrichment of both uranium and burnable absorbers for each fuel design. The B4C-Al fuel is most economical in overall cost even with large uncertainties. The overall cost of gadolinium and erbium cases are concluded to be about the same when large uncertainties are considered. en_US
dc.description.sponsorship Toshiba Corporation en_US
dc.publisher Massachusetts Institute of Technology. Center for Advanced Nuclear Energy Systems. Nuclear Fuel Cycle Program en_US
dc.relation.ispartofseries MIT-NFC;TR-64
dc.title Combining Thorium with Burnable Poison for Reactivity Control of a Very Long Cycle BWR en_US
dc.type Technical Report en_US
dc.contributor.mitauthor Inoue, Y.
dc.contributor.mitauthor Pilat, Edward E.
dc.contributor.mitauthor Xu, Z.
dc.contributor.mitauthor Kazimi, Mujid S.
dspace.orderedauthors Inoue, Y.; Pilat, Edward E.; Xu, Z.; Kazimi, Mujid S. en_US

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