@misc{oai:repo.qst.go.jp:00070466,
 author = {Ishii, Nobuyoshi and Koiso, Hiroyuki and Uchida, Shigeo and 石井 伸昌 and 小礒 寛之 and 内田 滋夫},
 month = {Jun},
 note = {Transuranic (TRU) waste containing radionuclides is generated during the operation and dismantling of reprocessing facilities and mixed oxide (MOX) fuel fabrication facilities.  In Japan, TRU waste for geological disposal is grouped into four gropes in accordance with physical properties and the concentration of radioactive materials.  Group 2 waste among four groups of TRU waste includes hull and end piece wastes, which are comprised of the debris and residue from the shearing and dissolution of the spent fuel assemblies.  The key nuclide in a geological repository for Group 2 waste is C-14, and leaching of organic C-14 compounds from simulated hull wastes has been reported.  Because organic C-14 is long-lived and has very little sorption properties, the possible migration of C-14 from a TRU repository site to the biosphere through groundwater presents some concern.  Therefore, it is necessary to understand the behavior of C-14 in the human habitation sphere on the assumption the C-14 derived from TRU wastes.
\nRice paddy field is one of important places to assess the behavior of C-14 because rice has long been a staple food in the Japanese diet and people may be expose to C-14 through rice intake.  Radioactive tracer experiments with [1,2-C-14] sodium acetate showed that more than 60% of the spiked C-14 was released from flooded paddy soil samples into the air as gas forms.  Rice plants may assimilate the released C-14 depending on chemical species.  The chemical species of the released C-14, however, have not been identified yet.  This paper will show the main chemical species of C-14 in gas phase, which was formed by decomposition of acetate by microorganisms in the paddy soil.
\nThis work has been partially supported by the Agency for Natural Resources and Energy, the Ministry of Economy, Trade and Industry (METI) Japan., International Conference on Radioecology and Environmental Radioactivity},
 title = {Determination of carbon species formed by decomposition of acetate in Japanese paddy soil},
 year = {2011}
}