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Study on Gaseous Effluent Treatment for Dissolution Step of Spent Nuclear Fuel Reprocessing.

DE2004828968

Publication Date	2002
Personal Author	Mineo, H.; Iizuka, M.; Sujisaki, S.; Hotoju, S.
Page Count	14
Abstract	Behavior of radioiodine and carbon-14 during spent fuel dissolution was studied in a bench-scale reprocessing test rig where 29 and 44 GWdt(sup -1) spent fuels were respectively dissolved. Decontamination factor of AGS (silica-gel impregnated with silver nitrate) column for iodine-129 removal was measured to be more than 36,000. The measurement of iodine-129 profile in the adsorption column showed that the nuclide was effectively trapped by the adsorbent. Measurement of iodine-129 in the dissolver solution after the iodine-stripping operation using NO(sub 2) gas at 363 K, revealed that less than 0.57% of total iodine-129 generated, which was estimated by ORIGEN II calculation, was remained in the dissolver solution. Also, measurement of iodine-129 by an iodine-stripping operation from the dissolver solution using potassium iodate showed that another 2.72% of total iodine-129 precipitated as iodide. In addition, about 70% of total iodine generated was measured in the AGS columns. Rest of iodine-129 was supposed to adsorb to a HEPA filter and the inner surface of dissolver off-gas lines. Those results on iodine-129 distribution were found to be almost identical to the results obtained in the study using iodine-131 as tracer and the results reported by other works. It was demonstrated that the two-steps iodine-stripping method using potassium iodate could expel additional iodine from the solution, more effectively than iodine-stripping operation using NO(sub 2) gas. Iodine-131 was also detected on the AGS columns at the spent fuel dissolution. Increasing burnup showed larger amount of iodine-131 since amount of curium-244 contained in the spent fuel increased with the burnup. Release of carbon-14 as carbon dioxide during dissolution was found to occur when the release of krypton-85. From the (sup 14) CO2 measurement, initial nitrogen-14 concentration in the fuel was estimated to be about several ppm, which was within the range reported.
Keywords	Spent fuels Radioactive waste management Dissolution Reprocessing Nuclear fuels Gaseous wastes Decontamination Silica gel Silver nitrates Iodine 129 Iodine 131 Curium 244 Burnup Carbon 14 Carbon dioxide Krypton 85 Nuclides
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Japan Atomic Energy Research Inst., Ibaraki.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200512

Study on Gaseous Effluent Treatment for Dissolution Step of Spent Nuclear Fuel Reprocessing.

Study on Gaseous Effluent Treatment for Dissolution Step of Spent Nuclear Fuel Reprocessing.
DE2004828968

Publication Date	2002
Personal Author	Mineo, H.; Iizuka, M.; Sujisaki, S.; Hotoju, S.
Page Count	14
Abstract	Behavior of radioiodine and carbon-14 during spent fuel dissolution was studied in a bench-scale reprocessing test rig where 29 and 44 GWdt(sup -1) spent fuels were respectively dissolved. Decontamination factor of AGS (silica-gel impregnated with silver nitrate) column for iodine-129 removal was measured to be more than 36,000. The measurement of iodine-129 profile in the adsorption column showed that the nuclide was effectively trapped by the adsorbent. Measurement of iodine-129 in the dissolver solution after the iodine-stripping operation using NO(sub 2) gas at 363 K, revealed that less than 0.57% of total iodine-129 generated, which was estimated by ORIGEN II calculation, was remained in the dissolver solution. Also, measurement of iodine-129 by an iodine-stripping operation from the dissolver solution using potassium iodate showed that another 2.72% of total iodine-129 precipitated as iodide. In addition, about 70% of total iodine generated was measured in the AGS columns. Rest of iodine-129 was supposed to adsorb to a HEPA filter and the inner surface of dissolver off-gas lines. Those results on iodine-129 distribution were found to be almost identical to the results obtained in the study using iodine-131 as tracer and the results reported by other works. It was demonstrated that the two-steps iodine-stripping method using potassium iodate could expel additional iodine from the solution, more effectively than iodine-stripping operation using NO(sub 2) gas. Iodine-131 was also detected on the AGS columns at the spent fuel dissolution. Increasing burnup showed larger amount of iodine-131 since amount of curium-244 contained in the spent fuel increased with the burnup. Release of carbon-14 as carbon dioxide during dissolution was found to occur when the release of krypton-85. From the (sup 14) CO2 measurement, initial nitrogen-14 concentration in the fuel was estimated to be about several ppm, which was within the range reported.
Keywords	Spent fuels Radioactive waste management Dissolution Reprocessing Nuclear fuels Gaseous wastes Decontamination Silica gel Silver nitrates Iodine 129 Iodine 131 Curium 244 Burnup Carbon 14 Carbon dioxide Krypton 85 Nuclides
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Japan Atomic Energy Research Inst., Ibaraki.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200512