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Journal Articles

Lessons learned from the process focusing on achieving the state of cold shutdown of Fukushima Daiichi Nuclear Power Plant Accident

Yoshizawa, Atsufumi*; Oba, Kyoko; Kitamura, Masaharu*

Ningen Kogaku, 54(3), p.124 - 134, 2018/06

Fukushima Daiichi Nuclear Power Plant caused a severe accident which released a large amount of radioactivity triggered by the Great East Japan Earthquake. The existing investigation reports of the accident prepared by several institutions pay attention only to the process which caused the accident but not much to the accident mitigation or the recovery process. This study focused on Unit 3 of Fukushima Daiichi Nuclear Power Plant, including its recovery process from the accident. Based on the public data, the time sequences for the recovery process between the accident occurrence and the state of cold shutdown were classified. Then, the groups of actions were sorted out in terms of ergonomics viewpoint. The important responses in the recovery process were identified and analyzed referring to the m-SHEL model. As a result, new lessons were learned from the accident case regarding the actions required for recovering from the accident.

Journal Articles

Investigation of hydrogen gas generation by radiolysis for cement-solidified products of used adsorbents for water decontamination

Sato, Junya; Kikuchi, Hiroshi*; Kato, Jun; Sakakibara, Tetsuro; Matsushima, Ryotatsu; Sato, Fuminori; Kojima, Junji; Nakazawa, Osamu

QST-M-8; QST Takasaki Annual Report 2016, P. 62, 2018/03

no abstracts in English

Journal Articles

The Survey for the integrity of containers for secondary wastes generated from contaminated water treatment

Iida, Yoshihisa; Nakadoi, Yasumasa; Yamaguchi, Tetsuji

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(1), p.53 - 64, 2017/06

The information on the contaminated water treatment in Fukushima Daiichi Nuclear Power Station announced by Tokyo Electric Power Co., Inc. (TEPCO) were summarized in terms of the management of the secondary wastes, for the purpose of accumulating technical knowledge for long-term storage of the wastes. Concerns for the long-term soundness of waste storage containers were pointed out as follows, corrosion of stainless steel containers exposed to radiation in the presence of chloride ions, corrosion of stainless steel containers under acidic conditions or in the presence of activated carbon, and radiation degradation of the high-performance container (HIC) in which slurry was stored.

Journal Articles

Removal of radioactive substances using inorganic compounds entangled by polymer chain grafted onto fiber

Saito, Kyoichi*; Kojima, Takashi*; Asai, Shiho

Bunseki Kagaku, 66(4), p.233 - 242, 2017/04

 Times Cited Count:1 Percentile:85.18(Chemistry, Analytical)

Insoluble cobalt ferrocyanide and sodium titanate specifically capture cesium and strontium ions, respectively, in water contaminated with radionuclides which is found in Fukushima Daiichi NPP. The inorganic compounds used in this study were formed as precipitates in the polymer chain grafted onto a commercially available 6-nylon fiber using radiation-induced graft polymerization. An impregnation structure with the precipitates entangled by the grafted polymer chain through an electrostatic interaction via multipoints was indicated. The resultant insoluble cobalt ferrocyanide- or sodium titanate-impregnated fiber exhibited a higher adsorption rate and adsorption capacity per gram of the inorganic compound for cesium or strontium ions in seawater than conventional granular adsorbents.

Journal Articles

The Hydrogen gas generation by electron-beam irradiation from ALPS adsorbents solidified by several inorganic materials

Sato, Junya; Suzuki, Shinji*; Kato, Jun; Sakakibara, Tetsuro; Meguro, Yoshihiro; Nakazawa, Osamu

QST-M-2; QST Takasaki Annual Report 2015, P. 87, 2017/03

no abstracts in English

Journal Articles

The Hydrogen gas generation by gamma-ray irradiation from ALPS adsorbents solidified by several inorganic materials

Sato, Junya; Suzuki, Shinji*; Kato, Jun; Sakakibara, Tetsuro; Meguro, Yoshihiro; Nakazawa, Osamu

QST-M-2; QST Takasaki Annual Report 2015, P. 88, 2017/03

no abstracts in English

Journal Articles

Additional information to report on site tour of the Fukushima Daiichi Nuclear Power Station

Suto, Toshiyuki

Genshiryoku, hoshasen Bukaiho (Internet), (19), P. 15, 2016/12

The Tritiated Water Task Force under METI's Committee on Countermeasures for Contaminated Water Treatment for Fukushima Daiichi Nuclear Power Plant (1F) reported that the option of post-dilution offshore release could dispose the tritiated water at a smallest cost in the shortest amount of time. The amount of tritium in the contaminated water at 1F was compared with ones released from nuclear power plants and reprocessing plants as some help for grasping its level of magnitude.

Journal Articles

Report on site tour of the Fukushima Nuclear Power Station

Suto, Toshiyuki

Gijutsushi, 28(11), p.8 - 11, 2016/11

Five years have passed since the accident of the Fukushima Daiichi Nuclear Power Station. The Nuclear and Radiation section of the Institute of Professional Engineers hosted a site tour of the plant to make themselves sure what is going on in it and to disseminate information about it. The conditions of landscape during traveling between the gathering place and the plant, each reactor, contaminated water treatment, site, and work environment improvement will be reported.

JAEA Reports

Application to contaminated water management in the Fukushima Daiichi Nuclear Power Station using the plastic scintillation fiber

Sanada, Yukihisa; Yamada, Tsutomu*; Sato, Yoshiharu; Nishizawa, Yukiyasu; Ishibashi, Satoshi*; Watanabe, Masahisa; Torii, Tatsuo

JAEA-Research 2016-011, 52 Pages, 2016/09

JAEA-Research-2016-011.pdf:10.54MB

In the Tokyo Electric Power Co.,Inc. the Fukushima Dai-ichi Nuclear Power Station, management of the contaminated water becomes the social problem, and the situation that severe correspondence is necessary continues to prevent an outflow to the ocean. Plastic scintillation fiber (PSF) can apply as technique to direct measure the concentration of radioactive material in the water at a tank and drainage. In this paper, the results of fundamental test was summarized to apply for monitoring of leakage to the tank and monitoring of drainage in the Fukushima Dai-ichi Nuclear Power Station.

Journal Articles

Speciation of iodine isotopes inside and outside of a contaminant plume at the Savannah River Site

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:7 Percentile:60.91(Environmental Sciences)

A new, accurate and simple pH-dependent solvent extraction method combined with accelerator mass spectrometry (AMS) measurement for $$^{129}$$I/$$^{127}$$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 $$^{129}$$I concentrations of 1 Bq/L or higher. This technique was applied to $$^{129}$$I-contaminated groundwater from the Savannah River Site, USA, and demonstrated changes of $$^{129}$$I and $$^{127}$$I concentrations and speciation along a pH, redox potential, and organic carbon gradient. The data suggest that $$^{129}$$I/$$^{127}$$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.

JAEA Reports

Experimental investigation of activities and tolerance of denitrifying bacteria under alkaline and reducing condition

Mine, Tatsuya*; ;

JNC-TN8430 2000-009, 35 Pages, 2000/07

JNC-TN8430-2000-009.pdf:0.88MB

In the geological disposal system of TRU wastes, nitrogen generation by denitrifying bacteria could provide significant impact on the assessment of this system, because nitrate contained in process concentrated liquid waste might be electron acceptor for denitrifying bacteria. In this study, the activities and tolerance of denitrifying bacteria under disposal condition were investigated. pseudomonas denitrificans as denitrifying bacteria was used. The results showed that Pseudomonas denitrificans had activity under reducing condition, but under high pH condition (PH$$>$$9.5), the activity of Pseudomonas denitrificans was not detected. It is possible that the activity of Pseudomonas denitrificans would be low under disposal condition.

JAEA Reports

Migration behavior of radionuclide in soil layer of final storage site; Radionuclide migration test in aerated soil layer by radioactive contaminated water

Yamamoto, Tadatoshi; Takebe, Shinichi; Ogawa, Hiromichi; Tanaka, Tadao; Mukai, Masayuki; Komiya, Tomokazu; *;

JAERI-M 89-144, 23 Pages, 1989/10

JAERI-M-89-144.pdf:0.87MB

no abstracts in English

Oral presentation

Leakage monitoring of the contaminated water by using PSFs in the Fukushima Daiichi NPP

Sanada, Yukihisa; Yamada, Tsutomu; Takamura, Yoshihide; Torii, Tatsuo

no journal, , 

no abstracts in English

Oral presentation

Corrosion resistance of tank material for flock storage

Ambai, Hiromu; Sano, Yuichi; Takeuchi, Masayuki; Koma, Yoshikazu

no journal, , 

We studied the corrosion behavior of the tank material SS400 for flock storage in fluid flow condition by air agitation. Fluid flow increased the corrosion rate and this effect was reduced by the presence of the flock. Decreasing of flow rate and change of air to inactive gas are effective in corrosion prevention measures.

Oral presentation

Evaluation of radiation resistance of inorganic materials for solidification of sludge from water treatment in Fukushima Daiichi NPS

Sato, Junya; Nakayama, Takuya; Kawato, Yoshimi; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Imaging XAFS analysis of secondary waste generated in the treatment process of contaminated water

Okamoto, Yoshihiro; Watanabe, So; Nagai, Takayuki; Kitawaki, Shinichi; Shibata, Atsuhiro; Nomura, Kazunori; Shiwaku, Hideaki

no journal, , 

Imaging XAFS analysis of simulated secondary waste generated from the treatment process of contaminated water in the Fukushima Daiichi Plant. The object in this study was titanate adsorption materials to collect strontium. Imaging XAFS data of the frame element Ti in the adsorption material and the target element Sr were obtained in the same domain of samples. Radiation effects in the secondary waste were simulated by $$gamma$$-ray and electron beam irradiation.

Oral presentation

Study of conditioning technologies of secondary wastes produced from contaminated water treatment, 4; Conditioning tests of simulated slurries with inorganic solidified materials

Sato, Junya; Suzuki, Shinji; Nakagawa, Akinori; Kato, Jun; Sakakibara, Tetsuro; Nakazawa, Osamu; Yamashita, Masaaki; Sato, Fuminori; Sukegawa, Hirobumi; Meguro, Yoshihiro

no journal, , 

no abstracts in English

Oral presentation

Oral presentation

Evaluation of hydrogen gas generation from inorganic solidified samples containing simulated ALPS slurries by electron beam irradiation

Sato, Junya; Suzuki, Shinji; Nakagawa, Akinori; Kato, Jun; Sakakibara, Tetsuro; Meguro, Yoshihiro; Nakazawa, Osamu

no journal, , 

no abstracts in English

39 (Records 1-20 displayed on this page)