Burning of MOX fuels in LWRs; fuel history effects on thermal properties of hull and end piece wastes and the repository performance |
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| Authors: | Fumio Hirano Tamotsu Kozaki Yaohiro Inagaki Tomohiko Iwasaki Toshiaki Ohe |
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| Affiliation: | 1. Division of Energy and Environmental Systems , Graduate School of Engineering , Hokkaido University , Sapporo , 060-8628 , Japan;2. Department of Applied Quantum Physics and Nuclear Engineering , Graduate School of Engineering, Kyushu University , Fukuoka , 819-0395 , Japan;3. Department of Quantum Science and Energy Engineering , Graduate School of Engineering, Tohoku University , Sendai , 980-8579 , Japan;4. Department of Nuclear Engineering, School of Engineering , Tokai University , Hiratsuka , Kanagawa , 259-1292 , Japan |
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| Abstract: | The thermal impacts of hull and end piece wastes from the reprocessing of MOX spent fuels burned in LWRs on repository performance were investigated. The heat generation rates in MOX spent fuels and the resulting heat generation rates in hull and end piece wastes change depending on the history of MOX fuels. This history includes the burn-up of UO2 spent fuels from which the Pu is obtained, the cooling period before reprocessing, the storage period of fresh MOX fuels before being loaded into an LWR, as well as the burn-up of the MOX fuels. The heat generation rates in hull and end piece wastes from the reprocessing of MOX spent fuels with any of those histories are significantly larger than those from UO2 spent fuels with burn-ups of 45 GWd/THM. If a temperature below 80°C is specified for cement-based materials used in waste packages after disposal, the allowable number of canisters containing compacted hull and end pieces in a package for 45 and 70 GWd-MOX needs to be limited to a value of 0.4–1.6, which is significantly lower than 4.0 for 45 GWd-UO2. |
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| Keywords: | MOX-LWR thermal impact history of MOX fuels hull and end piece waste burn-up cooling period cementitious material geological disposal |
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