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Kitayama, Ayami; Taniguchi, Naoki; Mitsui, Seiichiro
Materials and Corrosion, 72(1-2), p.211 - 217, 2021/01
Times Cited Count：0 Percentile：0.00(Materials Science, Multidisciplinary)Nakayama, Masashi; Saiga, Atsushi; Kimura, Shun; Mochizuki, Akihito; Aoyagi, Kazuhei; Ono, Hirokazu; Miyakawa, Kazuya; Takeda, Masaki; Hayano, Akira; Matsuoka, Toshiyuki; et al.
JAEA-Research 2019-013, 276 Pages, 2020/03
JAEA-Research-2019-013.pdf:18.72MB
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies for geological disposal of High-level Radioactive Waste through investigations of the deep geological environment within the host sedimentary rock at Horonobe Town in Hokkaido, north Japan. The investigations will be conducted in three phases, namely "Phase 1: Surface based investigations", "Phase 2: Construction phase" (investigations during construction of the underground facilities) and "Phase 3: Operation phase" (research in the underground facilities). According to the research plan described in the 3rd Mid- and Long- term Plan of JAEA, "Near-field performance study", "Demonstration of repository design option", and "Verification of crustal-movement buffering capacity of sedimentary rocks" are important issues of the Horonobe URL Project, and schedule of future research and backfill plans of the project will be decided by the end of 2019 Fiscal Year. The present report summarizes the research and development activities of these 3 important issues carried out during 3rd Medium to Long-term Research Phase.
Cs plumes from the Fukushima Daiichi Nuclear Power Plant; Evaluation of the model intercomparison data of the Science Council of JapanKitayama, Kyo*; Morino, Yu*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
Journal of Geophysical Research; Atmospheres, 123(14), p.7754 - 7770, 2018/07
Times Cited Count：26 Percentile：67.95(Meteorology & Atmospheric Sciences)We compared seven atmospheric transport model results for Cs released during the Fukushima Daiichi Nuclear Power Plant accident. All the results had been submitted for a model intercomparison project of the Science Council of Japan in 2014. We assessed model performance by comparing model results with observed hourly atmospheric concentrations of Cs, focusing on nine plumes over the Tohoku and Kanto regions. The results showed that model performance for Cs concentrations was highly variable among models and plumes. We also assessed model performance for accumulated Cs deposition. Simulated areas of high deposition were consistent with the plume pathways, though the models that best simulated Cs concentrations were different from those that best simulated deposition. The ensemble mean of all models consistently reproduced Cs concentrations and deposition well, suggesting that use of a multimodel ensemble results in more effective and consistent model performance.
Kitayama, Ayami; Nagata, Shuhei*; Inoue, Hiroyuki*; Dobashi, Ryuta*
no journal, ,
no abstracts in English
Kitayama, Ayami; Taniguchi, Naoki; Kimura, Wataru*; Kajiyama, Hiroshi*
no journal, ,
no abstracts in English
Suzuki, Hiroyuki*; Kitayama, Ayami; Mitsui, Seiichiro; Taniguchi, Naoki
no journal, ,
The environmental conditions around carbon steel overpacks in geological disposal are expected to be diverse cases depending on geological environment of the repository and may also vary depending on changes in conditions after repository closure. In this study, with the aim of understanding corrosion behavior under such environmental conditions, immersion tests with different conditions were conducted in bentonite/silica sando mixture assuming a buffer material to be constructed around the overpack under a wide range of conditions, including temperature and water quality beyond the assumed range of conventional environmental conditions, and the effects on corrosion behavior were evaluated.
Taniguchi, Naoki; Kitayama, Ayami; Kawasaki, Manabu*; Nakayama, Masashi; Ono, Hirokazu; Mitsui, Seiichiro; Suzuki, Hiroyuki*
no journal, ,
no abstracts in English
Watari, Shingo*; Kitayama, Ayami; Mitsui, Seiichiro; Taniguchi, Naoki; Kimura, Wataru*; Kajiyama, Hiroshi*
no journal, ,
The application of pure copper is being considered for the purpose of extending the life-time of disposal canisters in the direct disposal of spent fuel. Pure copper generally shows little corrosion development in aqueous solution environments with low oxygen concentrations due to its thermodynamic stability, but pure copper loses thermodynamic stability and corrosion develops depending on the sulfides conditions. In this study, immersion tests and U-bend tests were conducted to understand the corrosion progress behavior and stress corrosion cracking behavior of pure copper under the condition of sparging gas with various hydrogen sulfide concentrations to simulate the disposal environment where sulfide exists.
Cs due to the Fukushima Daiichi Nuclear Power Station accident based on the intercomparison of atmospheric dispersion modelsMorino, Yu*; Kitayama, Kyo*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
no journal, ,
For the evaluation of the validity and variability of atmospheric transport model results, we compared results of seven models submitted for the model inter-comparison project of Science Council of Japan to simulate Cs released from the Fukushima Daiichi Nuclear Power Plant. Model reproducibility was assessed with the observed hourly atmospheric concentrations of Cs in Tohoku and Kanto regions. Among nine plumes from 12 to 21 in March 2011, performance of the models was the best for the plume which dispersed over the Kanto region in 15 March. The models generally reproduced the observed Cs concentrations in plumes which widely spread inland of Tohoku or Kanto regions. By contrast, the models largely underestimated the observed Cs concentrations for the case which passed coastal areas of Japan. Ensemble average of seven models showed reasonable performance for most of plumes, and no individual models reproduced better than the ensemble average.
Nagata, Shuhei*; Inoue, Hiroyuki*; Kitayama, Ayami; Dobashi, Ryuta*
no journal, ,
no abstracts in English
Kitayama, Kyo*; Morino, Yu*; Takigawa, Masayuki*; Nakajima, Teruyuki*; Hayami, Hiroshi*; Nagai, Haruyasu; Terada, Hiroaki; Saito, Kazuo*; Shimbori, Toshiki*; Kajino, Mizuo*; et al.
no journal, ,
For the evaluation of the validity and variability of atmospheric transport model results, we compared results of seven models submitted for the model inter-comparison project of Science Council of Japan to simulate Cs released from the Fukushima Daiichi Nuclear Power Plant. Model reproducibility was assessed with the observed hourly atmospheric concentrations of Cs in Tohoku and Kanto regions. Among nine plumes from 12 to 21 in March 2011, performance of the models was the best for the plume which dispersed over the Kanto region in 15 March. The models generally reproduced the observed Cs concentrations in plumes which widely spread inland of Tohoku or Kanto regions. By contrast, the models largely underestimated the observed Cs concentrations for the case which passed coastal areas of Japan. Ensemble average of seven models showed reasonable performance for most of plumes, and no individual models reproduced better than the ensemble average.
Kitayama, Ayami; Taniguchi, Naoki; Mitsui, Seiichiro
no journal, ,
no abstracts in English
