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Journal Articles

Seven-year temporal variation of caesium-137 discharge inventory from the port of Fukushima Daiichi Nuclear Power Plant; Continuous monthly estimation of caesium-137 discharge in the period from April 2011 to June 2018

Machida, Masahiko; Yamada, Susumu; Iwata, Ayako; Otosaka, Shigeyoshi; Kobayashi, Takuya; Watanabe, Masahisa; Funasaka, Hideyuki; Morita, Takami*

Journal of Nuclear Science and Technology, 57(8), p.939 - 950, 2020/08

 Times Cited Count:3 Percentile:78.97(Nuclear Science & Technology)

After direct discharges of highly contaminated water of the Fukushima Daiichi Nuclear Power Plant (1F) from April to May 2011, Kanda suggested that relatively small amounts of run-off of radionuclides from the 1F port into the Fukushima coastal region subsequently continued by his estimation method. However, the estimation period was limited to up to September 2012. Therefore, this paper estimates the discharge inventory up to June 2018. In the missing period, the Japanese government and Tokyo Electric Power Company Holdings have continued efforts to stop the discharge, and consequently, the radionuclide concentration in seawater inside the 1F port has gradually diminished. We show the monthly discharge inventory of $$^{137}$$Cs up to June 2018 by two methods, i.e., Kanda method partially improved by the authors and a more sophisticated method using Voronoi tessellation reflecting the increase in the number of monitoring points inside the 1 F port. The results show that the former always yields overestimated results compared with the latter, but the ratio of the former to the latter is less than one order of magnitude. Using these results, we evaluate the impact of the discharge inventory from the 1F port into the coastal area and radiation dose upon fish ingestion.

Journal Articles

Seven-year temporal variation of cesium-137 discharge inventory from the port of Fukushima Dai-ichi Nuclear Power Plant; Continuous monthly estimation of cesium-137 discharge in the period from April 2011 to June 2018

Machida, Masahiko; Yamada, Susumu; Iwata, Ayako; Otosaka, Shigeyoshi; Kobayashi, Takuya; Watanabe, Masahisa; Funasaka, Hideyuki; Morita, Takami*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 18(4), p.226 - 236, 2019/12

After direct discharges of highly-contaminated water from Unit 2 and 3 in Fukushima Daiichi Nuclear Power Plant (1F) in April to May 2011, Kanda suggested that relatively small run-off of radionuclides from 1F port into Fukushima coastal region has subsequently continued by using his estimation scheme. However, the estimation period was limited until September 2012, and there has been no report on the issue since the work. Therefore, this paper focuses on discharge inventory from 1F port until June 2018. In the missing period, the central government and Tokyo Electric Power Company Holdings have done continuous efforts to stop the discharge, and consequently sea water concentration inside 1F port has diminished gradually. We show monthly discharge inventory of Cs-137 until June 2018 by two schemes, i.e., Kanda's scheme partially improved by authors and more sophisticated one using Voronoi tessellation reflecting the increment of the number of monitoring points inside 1F port. The results show that the former always presents overestimated results compared to the latter but the ratio of former to latter is less than one order. Based on these results, we evaluate impact of discharge inventory from 1F port into the coastal area and radiation does via fish digestion.

Journal Articles

Research and development activities for cleanup of the Fukushima Daiichi Nuclear Power Station

Sasaki, Toshiki; Kaminishi, Shuji*; Miyamoto, Yasuaki; Funasaka, Hideyuki

Materials Research Society Symposium Proceedings, Vol.1518, p.257 - 268, 2013/10

BB2012-2567.pdf:1.85MB

The Fukushima Daiichi Nuclear Power Station accident and restoration works have produced significant volume of radioactive waste. The waste has very different characteristics from usual radioactive waste produced in nuclear power stations and it requires extensive research and development for management of the waste. R&D works such as radionuclide analysis of the waste, hydrogen generation/diffusion analysis of a storage vessel, corrosion evaluation of storage vessels, etc. have been performed for characterization and safe storage of the waste. The detailed R&D plan for processing and disposal waste will be established by the end of FY2012.

Journal Articles

Research and development on next-generation reactor and related fuel cycle; Promotion of FBR cycle development for commercialization

Nagata, Takashi; Ichimiya, Masakazu; Funasaka, Hideyuki; Mizuta, Shunji; Nagura, Fuminori

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 51(4), p.234 - 238, 2009/04

no abstracts in English

Journal Articles

Current status on fuel cycle system of Fast reactor Cycle Technology Development (FaCT) project in Japan

Funasaka, Hideyuki; Nakamura, Hirofumi; Namekawa, Takashi

Proceedings of 16th Pacific Basin Nuclear Conference (PBNC-16) (CD-ROM), 6 Pages, 2008/10

On the FaCT project in Japan, six development issues for the advanced aqueous reprocessing system are identified. Crystallization is the one of the major technologies to recover a large amount of uranium from the dissolver solution. The residual solution is loaded to the extraction process for U, Pu and Np co-recovery. Raffinate solution from the extraction process contains FP and MA, where MA is extracted by chromatography. These processes are expected to be more efficient in costs, wastes management, and the plutonium proliferation. As for the fuel fabrication technology, six development issues are identified. The source powder preparation technology of the conversion and granulation process is the most essential for the simplified pelletizing method technology. Remote operation and remote maintenance technique is essential to handle the low decontaminated TRU fuel in a hot cell. Current development status and plan of this integrated system until around 2015 is reported.

Journal Articles

Current status and development plan on fuel cycle system of fast reactor cycle technology in Japan

Ito, Masanori; Funasaka, Hideyuki; Namekawa, Takashi

Proceedings of European Nuclear Conference 2007 (ENC 2007) (CD-ROM), 7 Pages, 2007/09

The FaCT project in Japan is implemented purposing to decide the adoption of innovative technologies by 2010 and to judge the prospect of the applicability of innovative technologies to the commercialized fast reactor cycle system by 2015. Innovative technologies to be developed are identified as six development issues for advanced aqueous reprocessing system and six ones for simplified pelletizing method fuel fabrication system. As for reprocessing technology, uranium crystallization and extraction chromatography are important. Wide range of development work from chemical fundamental study to engineering-scale equipment operation are planned and practiced. As for fuel fabrication, conversion and granulation are important to get the source MOX powder with good flowability. Development of modular equipments with grater remote maintenance performance and repairing system in a hot cell is essential to put the low decontaminated TRU fuel fabrication into practical use.

Journal Articles

Perspective and current status on fuel cycle system of Fast reactor Cycle Technology development (FaCT) project in Japan

Funasaka, Hideyuki; Ito, Masanori

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.259 - 267, 2007/09

FaCT Project taking over from Feasibility Study on Commercialized FR cycle system (FS) has been launched in 2006 by Japanese joint team with the participation of all parties concerned in Japan. Combination system of (the sodium-cooled reactor,) the advanced aqueous reprocessing system and the simplified pelletizing fuel fabrication (MOX fuel) is evaluated as the most promising fuel cycle system concept so that it has potential conformity to the design requirements, as well as a high level of technical feasibility as the final report of Phase II in FS. Current status and R&D prospects for this combination system of the advanced aqueous reprocessing system and the simplified pelletizing fuel fabrication (MOX fuel) system until around 2015 have been studied.

Journal Articles

Development of advanced head-end systems in "NEXT" process

Washiya, Tadahiro; Komaki, Jun; Funasaka, Hideyuki

Proceedings of International Conference on Advanced Nuclear Fuel Cycles and Systems (Global 2007) (CD-ROM), p.1467 - 1473, 2007/09

Japan Atomic Energy Agency (JAEA) has been developing the new aqueous reprocessing system named "NEXT" (New Extraction system for TRU recovery), which provides many advantages as waste volume reduction, cost savings by advanced components and simplification of process operation. Advanced head-end systems in the "NEXT" process consist of fuel disassembly system, fuel shearing system and continuous dissolver system. We developed reliable fuel disassembly system with innovative procedure, and short-length shearing system and continuous dissolver system can be provided highly concentrated dissolution to adapt to the uranium crystallization process. We have carried out experimental studies, and fabrication of engineering-scale test devices to confirm the systems performance. In this paper, research and development of advanced head-end systems are described.

Journal Articles

Waste management implications of advanced fuel cycle systems using Fast Reactors (FR)

Funasaka, Hideyuki; Koma, Yoshikazu; Sato, Koji; Nakajima, Yasuo; Shiotani, Hiroki; Kato, Atsushi; Higuchi, Tatsuya; Namba, Takashi

Proceedings of International Waste Management Symposium 2006 (WM '06) (CD-ROM), 13 Pages, 2006/02

Feasibility Study on commercialized FR cycle systems has been carried out by a Japanese joint team with the participation of all parties concerned in Japan since 1999. The result of the PhaseII (JFY 2001-2005) will work out until March 2006, and then the prospective of the promising concepts and the key issues for the commercialization will be summarized. In this paper, the candidate reprocessing systems studied in the Phase II are reviewed from the view point of compatibility with the reduction of environmental burden.

Journal Articles

Prospects and Progress Status of the Advanced Fuel Cycle System in Japan

Namba, Takashi; Funasaka, Hideyuki; Nagaoki, Yoshihiro; Sagayama, Yutaka

Proceedings of International Conference ATALANTE 2004 Advances for Future Nuclear Fuel Cycles (CD-ROM), 0 Pages, 2004/00

Experimental Study on Temperature Fluctuation Phenomena at T-pipe Junction(6)

Journal Articles

Present Status and Prospects in the FR Fuel Cycle System in Japan

Nakajima, Yasuo; Funasaka, Hideyuki; ; Nagaoki, Yoshihiro

Proceedings of 11th International Conference on Nuclear Engineering (ICONE-11) (CD-ROM), 0 Pages, 2003/00

Journal Articles

Advanced Fuel Cycle Stsyem and its R&D Plan in Japan

; Nomura, Shigeo; Ojima, Hisao; Funasaka, Hideyuki

Proceedings of International Conference on Advanced Nuclear Energy and Fuel Cycle Systems (GLOBAL 2003) (CD-ROM), p.1290 - 1298, 2003/00

None

Journal Articles

Advanced Fuel Cycle System and its R&D Plan in Japan

Nomura, Shigeo; Ojima, Hisao; Funasaka, Hideyuki

Proceedings of International Conference on Advanced Nuclear Energy and Fuel Cycle Systems (GLOBAL 2003) (CD-ROM), 1290 Pages, 2003/00

Three candidate systems of spent fuel reprocessing integrated with fuel fabrication process,i.e.advanced aqueous,oxide electrowinning and metal electrorefining are studied as the Feasibility Study(FS)Phase-2 for advanced fast reactor fuel cycle.

JAEA Reports

None

Funasaka, Hideyuki; ;

JNC TN1200 2001-002, 209 Pages, 2001/01

JNC-TN1200-2001-002.pdf:7.84MB

no abstracts in English

Journal Articles

None

; ; ; Myochin, Munetaka; ; Funasaka, Hideyuki

Saikuru Kiko Giho, (6), p.108 - 110, 2000/06

None

JAEA Reports

None

Oda, Yoshihiro; Funasaka, Hideyuki; *; Obara, Kenji*; *

JNC TY8400 2000-002, 47 Pages, 2000/03

JNC-TY8400-2000-002.pdf:2.53MB

no abstracts in English

JAEA Reports

Summary of the dissolution experiments of the irradiated fast reactor fuels in CPF

; Koyama, Tomozo; Funasaka, Hideyuki

JNC TN8400 2000-016, 188 Pages, 2000/03

JNC-TN8400-2000-016.pdf:3.6MB

We summarized the conditions and results of all dissolution experiments (bench scale experiments (dissolution of sheared fuel pins) and beaker scale experiments (dissolution of a few sheared fuels pieces) of the irradiated fast reactor fuels, which were carried out in the Chemical Processing Facility (CPF). The fabrication and irradiation conditions of the dissolved fuels were also put in order.

JAEA Reports

Study about the dissolution behavior of the irradiated fast reactor fuels in CPF

; Koyama, Tomozo; Funasaka, Hideyuki

JNC TN8400 2000-014, 78 Pages, 2000/03

JNC-TN8400-2000-014.pdf:2.13MB

We investigated the factors which affected the dissolution of U and Pu to the nitric acid solution with the fragmentation model, which was based on the results of dissolution experiments for the irradiated fast reactor fuels in the Chemical Processing Facility(CPF). The equation that gave the fuel dissolution rate was estimated with the condition of fabrication (Pu ratio (Pu/(U+Pu))), irradiation (burn-up) and dissolution (nitric acid concentration, solution temperature and U+Pu concentration) by evaluating these effects quantitatively. We also investigated the effects of fuel volume ratio to the solution in the dissolver, burn-up and flouring ratio of the fuel on the f-value (the parameter which shows the diffusion and osmosis of nitric acid to the fuel) in the fragmentation model. It was confirmed that the fuel dissolution rate calculated with this equation had better agreement with the results of dissolution experiments for the irradiated fast reactor fuels in the CPF than that estimated with the surface area model. In addition, the efficiency of this equation was recognized for the dissolution of unirradiated U pellet and high Pu enriched MOX fuel. It was shown that the dissolution rate of the fuel slowed down at the condition of the high U-Pu concentration dissolution by the calculation of the dissolution behavior with this equation. The dissolution of the fuel can be improved by increasing the nitric acid concentration and temperature, but from the viewpoint of lowering the corrosion of the dissolver materials, it is desirable that the f-value is increased by optimizing the condition of shearing and stirring for the improvement of dissolution.

Journal Articles

DIRECT EXTRACTION OF URANIUM AND PLUTONIUM FROM OXIDE USING SUPERCRITICAL CARBON DIOXIDE AND TBP-HNO3 COMPLEX.

Miyahara, Sachiko; Funasaka, Hideyuki; Enokida, Yoichi*; Yamamoto, Ichiro*

ATALANTE2000, 0 Pages, 2000/00

None

Journal Articles

QUANTUM CHEMISTRY STUDY FOR URANYL NITRATE COMPLEXES

Oda, Yoshihiro; Koyama, Tomozo; Funasaka, Hideyuki

Hoshasei Haikibutsu Shori Shobun To Saishori Ni Kansuru Nicchu Wakushoppu, 0 Pages, 2000/00

None

60 (Records 1-20 displayed on this page)