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Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Takahashi, Masa
Radiation Measurements, 137, p.106389_1 - 106389_5, 2020/09
Times Cited Count：0 Percentile：100(Nuclear Science & Technology)A portable thyroid dose monitoring system has been developed at the Japan Atomic Energy Agency (JAEA) to assess the thyroid equivalent dose for workers and members of the public in a high dose rate environment. The background (B.G.) photon correction is required for an accurate measurement in a high dose rate environment at an early stage after a nuclear accident. We developed the B.G. photon correction method using cylindrical PMMA phantoms.
, an iodine source for the immobilisation of radioiodineJohnstone, E. V.*; Bailey, D. J.*; Lawson, S.*; Stennett, M. C.*; Corkhill, C. L.*; Kim, M.*; Heo, J.*; Matsumura, Daiju; Hyatt, N. C.*
RSC Advances (Internet), 10(42), p.25116 - 25124, 2020/07
Nishino, Sho; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Takahashi, Masa
Radiation Measurements, 134, p.106292_1 - 106292_5, 2020/06
Times Cited Count：2 Percentile：10.96(Nuclear Science & Technology)In the situation of a severe nuclear accident, radioiodine monitoring in thyroid should be performed for a large number of people immediately after accident. The portable thyroid dose monitoring system which can be used in a high dose rate condition is in development. In this presentation, the result of performance test using prototype model will be described.
Guo, B.*; Xiong, Y.*; Chen, W.*; Saslow, S. A.*; Kozai, Naofumi; Onuki, Toshihiko*; Dabo, I.*; Sasaki, Keiko*
Journal of Hazardous Materials, 389, p.121880_1 - 121880_11, 2020/05
I impacted by atmospheric I releases from a spent nuclear fuel reprocessing plantOta, Masakazu; Terada, Hiroaki; Hasegawa, Hidenao*; Kakiuchi, Hideki*
Science of the Total Environment, 704, p.135319_1 - 135319_15, 2020/02
Times Cited Count：1 Percentile：40.89(Environmental Sciences)Land-surface transfers of I are modeled and incorporated into a land-surface model (SOLVEG-II), and the model was applied to the observed transfer of I at a vegetated field impacted by atmospheric releases of I from Rokkasho reprocessing plant during 2007 to investigate the importance of each I-transfer pathway. The model calculation revealed that contamination of leaves of wild bamboo grasses was mostly caused by foliar adsorption of I (81%) induced via wet deposition of I. Wet deposition of I was the main I-input to the soil, ten-fold the dry deposition of I; however, the deposition of I during 2007 was only 2% of the model-assumed I that pre-existed in the soil; indicating the importance of long-term accumulation of I in soils. The model calculation also revealed that root uptake of I, not methylation, control the long-term turnover of soil I.
bus FP results and single effect testingKnebel, K.*; Jokiniemi, J.*; Bottomley, D.
Journal of Nuclear Science and Technology, 56(9-10), p.772 - 789, 2019/09
Times Cited Count：3 Percentile：31.59(Nuclear Science & Technology)Revaporisation of the fission products deposited in the primary circuit of a reactor was identified as a possible late source of fission product release during a severe accident: eg. loss of coolant accident (LOCA). Subsequent testing has shown that revaporisation is very likely to occur given a breach of the reactor and is an important contributor for the source term release to the containment and biosphere. The first part reviews the revaporisation mechanisms of Cs and other volatile or semi-volatile fission products transported in the primary circuit that were derived from the Phebus FP and associated programmes. The second part examines the separate effects testing to determine the high temperature chemistry ofvolatile and semi-volatile fission products (I, Mo, Ru) and structural materials (Ag, B) as well as atmospheric effects which substantially affect the source term. Finally, it examines Cs data from reactor accident sites that is providing additional knowledge of longer-term fission product chemistry. The results have been summarised in the form of a table and schematic diagram. This accumulated knowledge and experience has important applications to minimising contamination during decommissioning and site remediation techniques, as well as improving SA simulation codes and raising nuclear safety.
I released from Fukushima Daiichi Nuclear Power Plant accident in the western North Pacific OceanSuzuki, Takashi; Otosaka, Shigeyoshi; Kuwabara, Jun; Kawamura, Hideyuki; Kobayashi, Takuya
JAEA-Conf 2018-002, p.103 - 106, 2019/02
To investigate the dynamics of radionuclides in the ocean released by the accident at Fukushima Daiichi Nuclear Power Plant (1F), vertical distributions of I at three stations in the western North Pacific was revealed. The 1F accident-derived I existed within the mixed layer at 3 stations. The maximum layer of the 1F accident-derived I existed at the depth of 370 m - 470 m at the most southern station. Considering the dissolved oxygen concentration and the current velocity arround the station, the maximum layer of the 1F accident-derived I would be fromed that I which existed in the surface seawater at other area of observation point was carried to the depth of 370 m - 470 m by the fast downward flow.
I in the seabed sediment off FukushimaOtosaka, Shigeyoshi; Sato, Yuhi*; Suzuki, Takashi; Kuwabara, Jun; Nakanishi, Takahiro
Journal of Environmental Radioactivity, 192, p.208 - 218, 2018/12
Times Cited Count：6 Percentile：55.71(Environmental Sciences)From August 2011 to October 2013, the concentration of iodine-129 (I) in the seabed sediment collected from 26 stations located within 160 km from the Fukushima Daiichi Nuclear Power Plant was estimated. The concentrations of I in seabed sediment off Fukushima in 2011 ranged between 0.02 and 0.45 mBq/kg. Although iodine is a biophilic element, the accident-derived radioiodine negligibly affects the benthic ecosystem. Until October 2013, a slightly increased activity of I in the surface sediment in the shelf-edge region (bottom depth: 200-400 m) was observed. The increase of the I concentrations in the shelf-edge sediments was affected by the (1) transport of I-bound particles from the land through rivers and (2) re-deposition of I desorbed from the contaminated coastal sediment to the shelf-edge sediments, which were considered to be dominant processes.
Shiotsu, Hiroyuki; Ito, Hiroto*; Ishikawa, Jun; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 6 Pages, 2018/11
I released from the Fukushima Daiichi Nuclear Power Plant in the Kuroshio and Oyashio current areasSuzuki, Takashi; Otosaka, Shigeyoshi; Kuwabara, Jun; Kawamura, Hideyuki; Kobayashi, Takuya
Marine Chemistry, 204, p.163 - 171, 2018/08
Times Cited Count：0 Percentile：100(Chemistry, Multidisciplinary)To investigate the penetration of radionuclides released from Fukushima Daiichi Nuclear Power Plant (FDNPP), depth profiles were revealed at Kuroshio current, transition, and Oyashio current areas. The FDNPP-derived I was found in surface layer at Oyashio current and transition areas and in sub-surface layer at Kuroshio current area. Moreover, it was found that the FDNPP-derived I/
Cs ratios in the Oyashio current and transition areas were higher than that in the FDNPP reactor. The higher FDNPP-derived I/Cs ratios suggest three potential mechanisms for the migration of radionuclides in the environment: (1) radioiodine was released more easily than radiocesium by the FDNPP accident, (2) I was supplied from the atmosphere by re-emitted I from contaminated areas around Fukushima, (3) leaked water that removed radiocesium reached the sampling stations. The FDNPP-derived I in sub-surface layer would be transported by the meander of the Kuroshio Extension current.
I concentrations in the air from pulse-height distribution observed by NaI(Tl) detector in monitoring postsYamada, Junya; Hashimoto, Makoto; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*
Radioisotopes, 65(10), p.403 - 408, 2016/10
The purpose of this study is to develop a quick method for estimation of I concentrations in the air using data measured by monitoring posts. In this method, I concentrations were estimated by multiplying I count rates at the full-energy peak measured with a NaI(Tl) detector by a concentration conversion factor. The concentration conversion factor for monitoring posts in JAEA Oarai Center was calculated with an EGS5 Monte Carlo code. As a result, the concentration conversion factor for an infinite-air-source was 25.7 Bq/m
/cps.
Hemmi, Ko
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), P. 113, 2016/06
no abstracts in English
Shibata, Keiichi
Journal of Nuclear Science and Technology, 52(9), p.1174 - 1185, 2015/09
Times Cited Count：2 Percentile：74.98(Nuclear Science & Technology)Neutron nuclear data on 6 isotopes of iodine have been evaluated for the next release of JENDL general purpose file in the energy region from 10
eV to 20 MeV. Except for 
I, the thermal capture cross sections were determined from a simplified formula. Unresolved resonance parameters were obtained for self-shielding calculations. On the other hand, a statistical model code CCONE was applied to calculate cross sections above the resolved resonance region. Coupled-channel optical-model potentials were employed for the interaction between neutrons and nuclei. The 
-ray strength functions for iodine isotopes were determined so as to reproduce measured -ray spectrum for 
I. The presently evaluated results are consistent with available experimental data, and found to be much better than the JENDL-4.0 evaluation. The evaluated data are compiled into ENDF formatted data files.
Hemmi, Ko; Yamaguchi, Tetsuji; Iida, Yoshihisa
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 22(1), p.3 - 10, 2015/06
Iodine and tin are important elements in performance assessment of geological disposal of radioactive wastes. Sorption experiments of iodine were carried out under varying nitrate concentration with a range of 0 to 5 mol dm
at neutral pH range in order to determine the distribution coefficient of iodine was zero or non-zero value. The experimental results with estimated statistical errors showed non-zero values for tuffaceous sandstone except for NaNO
concentration 0.5 mol dm. Non-zero values were also obtained under NaNO concentrations higher than 0.5 mol dm for granodiorite. Sorption experiments of tin were carried out at high pH range in order to check whether the distribution coefficient of tin decreases significantly with pH as a result of formation of anionic hydrolysis species of tin. The distribution coefficients of tin on granodiorite decreased from 9.79
10
m kg
at pH10.4 to 2.4610 m kg at pH12.4. The distribution coefficient of tin on tuffaceous sandstone was about one order of magnitude higher (about 210 m kg) than that of granodiorite at pH around 12.4.
Ishikawa, Jun; Ito, Hiroto; Maruyama, Yu
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05
Schwehr, K. A.*; Otosaka, Shigeyoshi; Merchel, S.*; Kaplan, D. I.*; Zhang, S.*; Xu, C.*; Li, H.-P.*; Ho, Y.-F.*; Yeager, C. M.*; Santschi, P. H.*; et al.
Science of the Total Environment, 497-498, p.671 - 678, 2014/11
Times Cited Count：10 Percentile：59.14(Environmental Sciences)A new, accurate and simple pH-dependent solvent extraction method combined with accelerator mass spectrometry (AMS) measurement for I/I isotopes and iodine speciation (iodide, iodate, and organo-I) quantification in liquids of any ionic strength has been developed. We then validated the AMS method for activity concentration measurements with a recently developed gas chromatography mass spectrometry method for I concentrations of 1 Bq/L or higher. This technique was applied to I-contaminated groundwater from the Savannah River Site, USA, and demonstrated changes of I and I concentrations and speciation along a pH, redox potential, and organic carbon gradient. The data suggest that I/I and species distribution is strongly pH dependent. The new method can now be applied to a wide range of chemically-diverse aquatic systems, including uncontaminated environments.
Hatsukawa, Yuichi; Toh, Yosuke; Oshima, Masumi; Kimura, Atsushi; Gharaie, M. H. M.
Journal of Radioanalytical and Nuclear Chemistry, 271(1), p.43 - 45, 2007/01
Times Cited Count：3 Percentile：72.41(Chemistry, Analytical)- coincidence of multiple -rays from the radioisotopes produced by neutron capture reactions was measured with a array of 19-Ge detectors with BGO Compton suppressors, GEMINI-II. Using multiparameter spectrometry, high sensitive determination of iridium in geological samples and I-129 in environmental samples were carried out at GEMINI.
Suzuki, Takashi; Kitamura, Toshikatsu; Kabuto, Shoji*; Togawa, Orihiko; Amano, Hikaru
Journal of Nuclear Science and Technology, 43(11), p.1431 - 1435, 2006/11
Times Cited Count：11 Percentile：35.35(Nuclear Science & Technology)no abstracts in English
Saeki, Masakatsu
JAERI-Review 2004-011, 54 Pages, 2004/03
JAERI-Review-2004-011.pdf:5.21MB
In this review, experimental results on studies of radioactive iodine, tritium and neptunium are summarized. On studies of radioactive iodine, from various experimental results, the process establishing the formation mechanism of organic iodides was fully described. On the basis of formation mechanism, possibilities for the formation of organic iodides under nuclear reactor accidents and so on were also discussed. On studies of tritium, three topics were concisely described on the isotopic composition of tritium gases, the chemical forms and the diffusivity of tritium in various materials, and the sorption and desorption behaviors of tritium on surfaces of various materials. On the neptunium chemistry, the relationship between the structure of neptunium compound and the Moessbauer isomer shift and experimental results on neptunyl(VI) hydroxides were discussed.
Kitamura, Toshikatsu; Kabuto, Shoji*; Suzuki, Takashi; Togawa, Orihiko; Kitada, Yoshinobu*; Watanabe, Yukiya*
Dai-16-Kai Tandemu Kasokuki Oyobi Sono Shuhen Gijutsu No Kenkyukai Hokokushu, p.27 - 31, 2004/02
no abstracts in English
