BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Apparent Diffusion Coefficients Consistent with Sorption Derived B ased on Changes in Depth Profiles of Radiocaesium in Soil Contaminated by the Fukushima Nuclear Accident and Future Prediction of Depth Profile DTSTART;VALUE=DATE-TIME:20171102T000000Z DTEND;VALUE=DATE-TIME:20171102T001500Z DTSTAMP;VALUE=DATE-TIME:20260814T130130Z UID:indico-contribution-343-1210@events01.synchrotron.org.au DESCRIPTION:Speakers: Haruo Sato (Okayama University)\nH. Sato and M. Yosh ii\, Okayama University\, 3-1-1\, Tsushima-naka\, Kita-ku\, Okayama-shi\, Okayama 700-8530\, Japan\n\nThe accident at the Fukushima Daiichi Nuclear Power Plant occurred following the Great East Japan Earthquake in March 20 11\, and led to the release of volatile radionuclides (RNs) which were dep osited on the surrounding environment in the Fukushima prefecture. The aut hors conducted twice investigations on the depth profiles of RNs in soil a t 11 locations in the city of Nihonmatsu and the towns of Kawamata and Nam ie.\nThe apparent diffusion coefficients (Da) of Cs-134 and Cs-137 were de rived from changes in the depth profiles\, and the distribution coefficien ts (Kd) also calculated from the relation with Da. The calculated Kd-value s ranged 1E4-1E5 ml/g\, which were consistent with Kd-values (2\,080-61\,0 00 ml/g) obtained by a batch method. The Da-values of both nuclides were a pproximately of order 1E-14 m2/s and movement by diffusion was very slow. Furthermore\, the authors simulated change in the depth profiles of both n uclides for 30 years following the accident.\n\nhttps://events01.synchrotr on.org.au/event/51/contributions/1210/ LOCATION: URL:https://events01.synchrotron.org.au/event/51/contributions/1210/ END:VEVENT BEGIN:VEVENT SUMMARY:Investigation of C-14 in the CRUD collected on the coolant filter for safety disposal of radioactive waste containing C-14 (I)- C-14 release behavior and thermal decomposition characteristics of crud particles coll ected from the coolant filter of commercial PWR - DTSTART;VALUE=DATE-TIME:20171102T001500Z DTEND;VALUE=DATE-TIME:20171102T003000Z DTSTAMP;VALUE=DATE-TIME:20260814T130130Z UID:indico-contribution-343-1161@events01.synchrotron.org.au DESCRIPTION:Speakers: Kenichiro Kino (Nucler Development Corporation)\nIn the safety assessment of radioactive waste repository\, it is important to evaluate the migration behavior of long half-life radionuclides in the di sposal environment. It was reported that insoluble C-14 was generated in P WR. However\, the knowledge about the chemical form of C-14 is little.\nIn this study\, particles including C-14 collected from the coolant filters in PWR were analyzed by TG/MS to identify the chemical forms of these part icles. In addition\, C-14 in released gases and the residue in TG measurem ents were also investigated.\nResultantly\, it was revealed that fragments which were considered to be organic compounds derived from the ion-exchan ge resin were detected from the released gas\, and that majority(>90%) of C-14 inventory were detected in the residue after the inert gas heating.\n While the chemical forms of C-14 in the residue are not clarified\, it is suggested that insoluble C-14 may exist in the thermo-stable compounds.\n\ nhttps://events01.synchrotron.org.au/event/51/contributions/1161/ LOCATION: URL:https://events01.synchrotron.org.au/event/51/contributions/1161/ END:VEVENT BEGIN:VEVENT SUMMARY:Investigation of C-14 in the CRUD collected on the coolant filter for safety disposal of radioactive waste containing C-14 (II) –Chemical alternation of ion exchange resin under simulated condition in primary coo lant of PWR – DTSTART;VALUE=DATE-TIME:20171102T003000Z DTEND;VALUE=DATE-TIME:20171102T004500Z DTSTAMP;VALUE=DATE-TIME:20260814T130130Z UID:indico-contribution-343-1153@events01.synchrotron.org.au DESCRIPTION:Speakers: Kotaro Nakata (CRIEPI)\nRadiocarbon (C-14) is recogn ized as a radionuclide that includes significant impact on public exposure in safety assessment of radioactive waste disposal. Its origin\, generati on mechanism and chemical forms in the wastes are required to be understoo d for the reasonable and proper safety assessment of the radioactive waste disposal. Some previous studies have reported occurrence of insoluble C-1 4 in PWR\, and suggested that ion-exchange resin could be its origin. Howe ver\, this hypothesis has not been well evidenced yet\, because informatio n about the generation mechanism and chemical form of the insoluble C-14 i s still limited.\nIn this study\, alternation of the resin under heating a nd/or irradiation was investigated to understand the alternation of the re sin in PWR. In addition\, characteristics of CRUD on a coolant filter for the actual PWR were compared to those of the heated/irradiated resin. The results suggested that the insoluble C-14 arises from alternation of the i on-exchange resin.\n\nhttps://events01.synchrotron.org.au/event/51/contrib utions/1153/ LOCATION: URL:https://events01.synchrotron.org.au/event/51/contributions/1153/ END:VEVENT BEGIN:VEVENT SUMMARY:Digital autoradiography on C-14 labelled PMMA impregnated rock sam ples using the Beaver$^{TM}$ DTSTART;VALUE=DATE-TIME:20171102T004500Z DTEND;VALUE=DATE-TIME:20171102T010000Z DTSTAMP;VALUE=DATE-TIME:20260814T130130Z UID:indico-contribution-343-1123@events01.synchrotron.org.au DESCRIPTION:Speakers: Mikko Voutilainen (Department of Chemistry\, Univers ity of Helsinki\, Finland)\nIn Finland and Sweden KBS-3 concept has been c hosen for disposal of spent nuclear fuel in crystalline rock. Recent trans port experiments have shown that heterogeneity of rock may play a major ro le in transport of radionuclides. Autoradiographic methods has been proven to be able to assist the characterization of heterogeneous structures. In this study we tested a novel digital autoradiographic device called Beave r$^{TM}$ which applies a Micro Patterned Gaseous Detector in order to quan titatively map beta emissions by C-14 atoms. The studied samples were impr egnated with C-14 labelled MMA (Methyl MethAcrylate) and polymerized to PM MA using heat. The Beaver$^{TM}$ was then used to determine concentration of C-14 atoms which can then be converted to porosity based on the amount of C-14 intruded into the rock sample. The resulting images show a heterog eneous distribution of porosity which arises from the different porosities of minerals. The samples were chosen from three sites that has been used recently in *in situ* diffusion experiments: Olkiluoto (Finland)\, Äspö (Sweden) and Grimsel (Switzerland).\n\nhttps://events01.synchrotron.org.au /event/51/contributions/1123/ LOCATION: URL:https://events01.synchrotron.org.au/event/51/contributions/1123/ END:VEVENT END:VCALENDAR