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Hirayama, Hideo*; Kawasaki, Masatsugu; Matsumura, Hiroshi*; Okura, Takehisa; Namito, Yoshihito*; Sanami, Toshiya*; Taki, Mitsumasa; Oishi, Tetsuya; Yoshizawa, Michio
Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.295 - 307, 2021/10
Saito, Hiroshi; Sato, Yasushi*; Sakamoto, Atsushi*; Torikai, Kazuyoshi; Fukushima, Shigeru; Sakao, Ryota; Taki, Tomihiro
JAEA-Technology 2015-063, 119 Pages, 2016/03
JAEA-Technology-2015-063.pdf:86.2MB
Ningyo-toge Environmental Engineering Center has been conducting environmental remediation of the Ningyo-toge Uranium Mine, after decades of mine-related activities were terminated. Its purposes are to take measures to ensure safety and radiation protection from the exposure pathways to humans in future, and to prevent the occurrence of mining pollution. As part of the remediation, upstream part of the Yotsugi Mill Tailings Pond, the highest prioritized facility, has been remediated to fiscal year 2012. Multi-layered capping has been constructed using natural material, after specifications and whole procedure being examined in terms of long-term stability, radiation protection, economics, etc. Monitoring has been carried out to confirm the effectiveness of the capping, in terms of settlement, dose and radon exhalation rates, etc. Monitoring of drainage volume of penetrated rainwater is planned. Accumulated data will be examined and used for remediation of downstream part of the Pond.
Hirayama, Hideo*; Kawasaki, Masatsugu; Matsumura, Hiroshi*; Okura, Takehisa; Namito, Yoshihito*; Sanami, Toshiya*; Taki, Mitsumasa; Oishi, Tetsuya; Yoshizawa, Michio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(3), p.119 - 126, 2014/09
A method of deducing the I-131 concentration in a radioactive plume from the time history of peak count rates determined from pulse height spectra obtained from an NaI(Tl)scintillation detector employed as a detector of a monitoring post was presented. The concentrations of I-131 in the plumes were estimated from the count rates using the calculated response of the NaI(Tl) detector with egs5 for a model of a plume uniformly containing I-131. This method was applied to the data from the monitoring posts at Nuclear Science Research Institutes of Japan Atomic Energy Agency (JAEA). The estimated time history variation of I-131 concentrations in plumes was in fair agreement with those measured directly by an air sampling method. The difference was less than a factor of 4 for plumes that arrived on March 15 and March 21, indicating relatively high I-131 concentrations among the plumes studied in this work.
Sakao, Ryota; Saito, Hiroshi; Torikai, Kazuyoshi; Taki, Tomihiro
Journal of MMIJ, 130(6), p.275 - 278, 2014/06
Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency has been managing the Ningyo-toge Uranium Mine and Togo Uranium Mine in accordance with the Mine Safety laws. This paper shows a summary of the remediation activities of Mill Tailings Pond including the strategy and monitoring.
Fukushima, Shigeru; Taki, Tomihiro; Saito, Hiroshi; Torikai, Kazuyoshi; Sato, Yasushi*
Nihon Chikasui Gakkai 2013-Nen Shuki Koenkai Koen Yoshi, p.258 - 263, 2013/10
no abstracts in English
Saito, Hiroshi; Taki, Tomihiro
Proceedings of 15th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2013) (CD-ROM), 4 Pages, 2013/09
Ningyo-toge Environmental Engineering Center has been managing the Ningyo-toge Uranium Mine. The Mine is subject to environmental remediation to ensure the radiation protection from the exposure pathways to humans in future, and to prevent occurrence of mining pollution. The Yotsugi Mill Tailings Pond is considered as the highest prioritized facility. So far, capping is put on the stable upstream part of the Pond to reduce dose rate, radon exhalation and rainwater precipitation. Prior to its construction, it was decided that the capping are to be multi-layered and natural materials are to be used, and the capping specifications were decided. Also, drainage channels and gabion work are constructed around the capping and at the foot of capping slope, respectively. Monitoring, which will continue for years, has started to confirm the effectiveness of the capping and the data will be utilized for the future remediation of the downstream of the Pond.
Saito, Hiroshi; Taki, Tomihiro
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.533 - 537, 2010/10
Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency (JAEA) has maintained and preserved the Ningyo-toge and Togo Mines under the related laws, including the Mine Safety Law. JAEA has been planning to close these mines to prevent mine-pollution and reduce radiological impact to as low as achievably possible, for lasting protection of individuals and the environment. Among the mine-related facilities that are subject to environmental remediation, the Mill Tilings Pond is given the top priority. So far, basic concept has been discussed in parallel with data acquisition and designing for some of remediation activities.
Saito, Hiroshi; Taki, Tomihiro
Journal of MMIJ, 126(6), p.239 - 242, 2010/05
Ningyo-toge Environmental Engineering Center, Japan Atomic Energy Agency (JAEA) has maintained and preserved the Ningyo-toge and Togo Mines under the related laws, including the Mine Safety Law. JAEA has been planning to close these Mines to prevent mine-pollution and reduce radiological impact to as low as achievably possible, for lasting protection of individuals and the environment. Among the mine-related facilities that are subject to environmental remediation, the Mill Tilings Pond is given the top priority. So far, basic concept has been discussed in parallel with data acquisition and designing for some of remediation activities.
h analysis (Contract research)Otsuka, Ichiro; Taki, Hiroshi*; Yamaguchi, Tetsuji; Iida, Yoshihisa; Yamada, Fumika; Inada, Daisuke*; Tanaka, Tadao
JAEA-Research 2008-043, 101 Pages, 2008/03
JAEA-Research-2008-043.pdf:6.24MB
The influence of carbon steel overpack corrosion on redox potential (h) of bentonite pore water under geological disposal environment was investigated. The thermodynamics data of corrosion products, the corrosion rate of carbon steel, and the information on cathode reactions were acquired by experiments and literature survey. We conducted preliminary analysis of h, ascertained the validity of Phreeq C and identified important points on the analysis. Results were summarized as follows. (1) Thermodynamic data of Fe
, FeOH
, Fe(OH)
(aq), Fe(OH)
, Fe(OH)
, Fe
, FeS(pyrite), FeCO(siderite),Fe(OH)(s), FeO(magnetite), Fe(cr) were determined by literature survey. The solubility product of FeCO(OH) was determined experimentally, and thermodynamic data were estimated. (2) The corrosion rate of carbon steel was obtained as a function of pH and sulfide ion concentration. (3) After corrosion tests of carbon steel, no CH, HS and HS, the reduction product of CO and SO,were not detected in liquid and gas phases. (4) Preliminary analysis showed that the redox couple changed as HS(aq)/SO, CH(aq)/CO, H(aq)/HO during the evaluation period. After 1000 years, h attained about -500 to -600 mV (vs. NHE) or -750 mV controlled by CH(aq)/CO,or H(aq)/HO, respectively.
Yamaguchi, Tetsuji; Sakamoto, Yoshifumi; Iida, Yoshihisa; Negishi, Kumi; Taki, Hiroshi; Akai, Masanobu; Jinno, Fumika; Kimura, Yuichiro; Ueda, Masato; Tanaka, Tadao; et al.
Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10
no abstracts in English
Iida, Yoshihisa; Taki, Hiroshi; Yamaguchi, Tetsuji; Tanaka, Tadao; Negishi, Kumi; Nakayama, Shinichi
JAERI-Conf 2005-007, p.230 - 235, 2005/08
A variation in data should be quantitatively incorporated in a probabilistic safety assessment of radioactive waste disposal. We focus our experimental efforts on parameters that induce major uncertainties in the radionuclide migration analysis and that have not been quantitatively assessed. Possible sources of uncertainty includes increase in ionic strength of groundwater caused by intrusion of seawater and/or dissolution of sodium nitrate in TRU waste, highly alkaline conditions originating from cementitious materials, and a variation of porewater composition accompanied with corrosion of. This study is a summary of current status of our investigations for solubility and diffusion.
Kando, Masaki; Ahn, H.; Dewa, Hidenori; Kotaki, Hideyuki; Ueda, Toru*; Uesaka, Mitsuru*; Watanabe, Takahiro*; Nakanishi, Hiroshi*; Ogata, Atsushi*; Nakajima, Kazuhisa
Japanese Journal of Applied Physics, Part 2, 38(8B), p.L967 - L969, 1999/08
Times Cited Count：23 Percentile：69.06(Physics, Applied)no abstracts in English
Kotaki, Hideyuki; Nakajima, Kazuhisa*; Kando, Masaki*; Dewa, Hidenori*; Kondo, Shuji; *; Watanabe, Takahiro*; Ueda, Toru*; Nakanishi, Hiroshi*; Yoshii, Koji*; et al.
Inst. Phys. Conf. Ser., (159), p.565 - 567, 1999/00
no abstracts in English
Kando, Masaki; Kotaki, Hideyuki; Dewa, Hidenori; Kondo, Shuji; Yoshii, Koji*; Ueda, Toru*; Watanabe, Takahiro*; Uesaka, Mitsuru*; Sakai, Fumio*; Ogata, Atsushi*; et al.
Proceedings of 24th Linear Accelerator Meeting in Japan, p.128 - 130, 1999/00
no abstracts in English
Nakajima, Kazuhisa; Nakanishi, Hiroshi*; Ogata, Atsushi*; Harano, Hideki*; Ueda, Toru*; Uesaka, Mitsuru*; Watanabe, Takahiro*; Yoshii, Koji*; Dewa, Hidenori; Hosokai, Tomonao; et al.
Proceedings of 6th European Particle Accelerator Conference (EPAC98) (CD-ROM), p.809 - 811, 1998/01
no abstracts in English
Dewa, Hidenori*; H.Ahn*; Harano, Hideki*; Kando, Masaki*; Kinoshita, Kenichi*; Kondo, Shuji; Kotaki, Hideyuki; Nakajima, Kazuhisa*; Nakanishi, Hiroshi*; Ogata, Atsushi*; et al.
Nuclear Instruments and Methods in Physics Research A, 410(3), p.357 - 363, 1998/00
Times Cited Count：40 Percentile：92.83(Instruments & Instrumentation)no abstracts in English
Kotaki, Hideyuki; Nakajima, Kazuhisa*; Kando, Masaki*; H.Ahn*; Dewa, Hidenori*; Kondo, Shuji; *; Watanabe, Takahiro*; Ueda, Toru*; Nakanishi, Hiroshi*; et al.
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.449 - 451, 1997/00
no abstracts in English
*; Kotaki, Hideyuki; Nakajima, Kazuhisa*; Kando, Masaki*; Kondo, Shuji; Dewa, Hidenori*; Watanabe, Takahiro*; Ueda, Toru*; Yoshii, Koji*; Kinoshita, Kenichi*; et al.
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.473 - 475, 1997/00
no abstracts in English
Kotaki, Hideyuki; Nakajima, Kazuhisa*; Kando, Masaki*; H.Ahn*; Dewa, Hidenori*; Kondo, Shuji; *; Watanabe, Takahiro*; Ueda, Toru*; Nakanishi, Hiroshi*; et al.
Proc. of 11th Symp. on Accelerator Sci. and Technol., p.513 - 515, 1997/00
no abstracts in English
Tanaka, Tadao; Yamaguchi, Tetsuji; Iida, Yoshihisa; Kimura, Yuichiro; Taki, Hiroshi; Fujiwara, Takeshi; Ueda, Masato*; Mukai, Masayuki; Yamada, Fumika; Mizuno, Tsuyoshi; et al.
no journal, ,
no abstracts in English
