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Journal Articles

Electron microscopic analysis of radiocaesium-bearing microparticles in lichens collected within 3 km of the Fukushima Dai-ichi Nuclear Power Plant

Dohi, Terumi; Tagomori, Hisaya; Omura, Yoshihito*; Fujiwara, Kenso; Kanaizuka, Seiichi*; Iijima, Kazuki

Environmental Radiochemical Analysis VI, p.58 - 70, 2019/09

In this study we established a separation method for radiocaesium-bearing microparticles (CsMPs) from lichens using electron microscopic analysis. Lichens were first digested within hydrogen peroxide and then an automatic particle analyser system based on FE-EPMA was used for detecting CsMPs within lots of mineral-like and metallic particles quickly. The elemental composition and radiocaesium activities of the separated CsMPs were measured, and the results show that the digestion treatment did not influence the CsMPs characteristics. An inhomogeneous elemental distribution was found in some CsMPs by two-dimensional elemental analysis using FE-EMPA. Our methods for separation of CsMPs and analysing their elemental composition are expected to be useful for grasping the chemical composition trends of CsMPs statistically.

JAEA Reports

Separation of radiocaesium-bearing micro particle from environmental samples; Application to litter samples

Tagomori, Hisaya; Dohi, Terumi; Ishii, Yasuo; Kanaizuka, Seiichi*; Fujiwara, Kenso; Iijima, Kazuki

JAEA-Technology 2019-001, 37 Pages, 2019/03

JAEA-Technology-2019-001.pdf:26.85MB

An efficient methodology for separating the radiocaesium-bearing micro particles (CsMPs) released by the TEPCO's Fukushima Dai-ichi Nuclear Power Station accident is required to investigate their spatial distribution and physicochemical properties. In this report we developed an efficiency separation method for CsMP from litters since the radiocaesium in litter may affect the radiocaesium cycling in forest ecosystem. One CsMP separation from litter containing lots of soil particles was attained within three days using electron microscopic analysis with digestion treatment of organic matter. This methodology is expected as CsMPs efficient separation method for not only forest floor litter but also barks and leaves of living tree, and other organic materials in the forested environment.

Journal Articles

Outline of decommissioning plan of Tokai Reprocessing Plant

Okano, Masanori; Akiyama, Kazuki; Taguchi, Katsuya; Nagasato, Yoshihiko; Omori, Eiichi

Dekomisshoningu Giho, (57), p.53 - 64, 2018/03

The construction of Tokai Reprocessing Plant (TRP) was initiated in June 1971, and its hot test using spent fuel started in September 1977. Thereafter TRP had been operated to reprocess 1,140 tons of spent fuel for approximately 30 years until May 2007, according to the reprocessing contract with domestic electric power companies. JAEA announced a policy of TRP in report of JAEA reform plan published in September 2014. The policy shows that TRP will shift to a decommissioning stage by economic reasons. Based on the policy, application of approval for TRP decommissioning plan was submitted to Nuclear Regulation Authority (NRA) in June 2017. This plan provides basic guidelines such as procedures for decommissioning and specific activities for risk reduction, and implementation divisions of decommissioning, management of spent fuels and radioactive wastes, decommissioning budget, and decommissioning schedule. The process of TRP decommissioning is planned to continue for approximately 70 years until the release of controlled areas of approximately 30 facilities.

Journal Articles

Monitoring of positron using high-energy gamma camera for proton therapy

Yamamoto, Seiichi*; Toshito, Toshiyuki*; Komori, Masataka*; Morishita, Yuki*; Okumura, Satoshi*; Yamaguchi, Mitsutaka; Saito, Yuichi; Kawachi, Naoki; Fujimaki, Shu

Annals of Nuclear Medicine, 29(3), p.268 - 275, 2015/04

 Times Cited Count:12 Percentile:57.86(Radiology, Nuclear Medicine & Medical Imaging)

Journal Articles

Study of solvent degradation in reprocessing MOX spent fuel; Solvent degradation and its effect on Pu purification cycle

Kawaguchi, Yoshihito; Morimoto, Kazuyuki; Kitao, Takahiko; Oyama, Koichi; Omori, Eiichi

Nihon Genshiryoku Gakkai Wabun Rombunshi, 8(3), p.221 - 229, 2009/09

30% Tributyl phosphate (TBP)/n-dodecane is used on PUREX process in Tokai Reprocessing Plant (TRP). TBP is degraded to di-butyl phosphate (DBP), mono-butyl phosphate (MBP) etc. mainly caused by radiation, extracted element and hydrolysis. In this study, we studied TBP degradation kinetic equation, Pu concentration in high DBP concentration solution after stripping Pu from the solution by diluted HNO$$_{3}$$, DBP concentration in mixer-settler and effect for process while MOX spent fuel was reprocessed and operation was stopped with Pu loaded on solution for 20 days. As a result of this study, we obtained the equation of TBP degradation. Moreover, the maximum DBP concentration in mixer-settler while reprocessing MOX spent fuel was 91 ppm, DBP concentration while stopping operation was 2000 ppm and we found out there was nothing out of the ordinary on the process after the process was restarted.

Journal Articles

None

Nomura, Shigeo; Kikuchi, Ko; Omori, Eiichi; Inano, Masatoshi

Enerugi, 38(6), p.59 - 62, 2005/00

None

Journal Articles

A Development and an application of MIXSET-X computer code for simulating the purex solvent extraction system

Ishida, Michihiko; Sudo, Toshiyuki; Omori, Eiichi; Nojiri, Ichiro

Vol.1 No.040, 1(40), 0 Pages, 2001/00

None

JAEA Reports

Facility damages by the explosion

; Omori, Eiichi; Kato, Yoshiyuki; Suzuki, Hiroshi; Shimoyamada, Tetsuya; Tomiyama, Masahiro; Shimokura, Mitsuharu; Sakuraba, Terumi; Morimoto, Kyoichi; Hagiwara, Masayoshi; et al.

PNC TN8410 98-013, 1028 Pages, 1998/01

PNC-TN8410-98-013.pdf:143.04MB

None

Journal Articles

The Fire and Explosion Incident at Bituminization Demonstration Facility of PNC Tokai Works

Koyama, Tomozo; ; ; Omori, Eiichi; ; ; Kitatani, Fumito; Kosugi, Kazumasa; Sudo, Toshiyuki; Kikuchi, Naoki; et al.

Nihon Genshiryoku Gakkai-Shi, 40(10), p.740 - 766, 1998/00

 Times Cited Count:1 Percentile:15.58(Nuclear Science & Technology)

None

JAEA Reports

Pressure analysis in ventilation ducts at Bituminization Facility

Kikuchi, Naoki; Iimura, Masato*; Takahashi, Yuki*; Omori, Eiichi; Yamanouchi, Takamichi

PNC TN8410 97-310, 117 Pages, 1997/09

PNC-TN8410-97-310.pdf:5.43MB

Pressure analysis in cell ventilation ducts at bituminization facility where the fire and explosion accident occured was carried out. This report also describes the results of bench mark calculations for computer code EVENT84 which was used for the accident analysis. The bench mark calculations were performed by comparing the analytical results by EVENT84 code with the experimental data of safety demonstration tests of ventilation system which were carried out by JAERI. We confirmed the applicability of EVENT84 code with the conservative results. The pressure analysis in cell ventilation ducts at bituminization facility were performed by comparing the analytical results of duct pressure by EVENT84 code with the yield stress of destroyed ducts by explosion, in order to estimate the scale of explosion. As a result, we could not explain the damage of ducts quantitatively, but we found the local pressure peaks analytically in downstream ducts where the serious damages were observed.

Journal Articles

None

Shigetome, Yoshiaki; ; Omori, Eiichi; Koyama, Tomozo

Kuki Seijo, , 

None

Oral presentation

Study of neptunium behavior in extraction process of Tokai reprocessing plant, 1; Results on balance of neptunium in extraction process

Nagaoka, Shinichi; Morimoto, Kazuyuki; Sato, Takehiko; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

no abstracts in English

Oral presentation

Oral presentation

Three decades of forward steps and prospect in Tokai reprocessing plant, 5; Corrosion of equipments holding high-concentrated plutonium nitrate solution in Tokai reprocessing plant

Obu, Tomoyuki; Morimoto, Kazuyuki; Yoshinari, Toshimi; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

no abstracts in English

Oral presentation

MOX reprocessing at Tokai reprocessing plant

Taguchi, Katsuya; Nagaoka, Shinichi; Yamanaka, Atsushi; Sato, Takehiko; Nakamura, Yoshinobu; Omori, Eiichi; Miura, Nobuyuki

no journal, , 

no abstracts in English

Oral presentation

MOX reprocessing at TRP, 5; Evaluation for temperature of plutonium product in storage

Kurabayashi, Kazuaki; Kawaguchi, Yoshihito; Takaya, Akikazu; Morimoto, Kazuyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

Plutonium product recovered from Fugen MOX type B spent fuel is measured temperature at Tokai Reprocessing Plant. And we studied difference between estimated by ORIGEN and analytical value of relative promotion on Pu, moreover, we studied calculation model because of the difference between initial evaluation and temperature of Pu product.

Oral presentation

MOX reprocessing at TRP, 6; Study of solvent degradation

Hoshi, Takahiro; Kawaguchi, Yoshihito; Kitao, Takahiko; Oyama, Koichi; Morimoto, Kazuyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

For reprocessing nuclear spent fuel, in future, used for plutonium-thermal and fast-breeding reactor, density of DBP in extraction solvent on reprocessing Fugen MOX Type B fuel was measured. And we formulated an equation for increased density of DBP to estimate density of DBP in extraction cycle.

Oral presentation

MOX reprocessing at TRP, 4; Control test of Neptunium extraction

Kawakami, Yoshiyuki; Nagaoka, Shinichi; Kitao, Takahiko; Morimoto, Kazuyuki; Obu, Tomoyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

We are trying to research how acidity and temperature influences Np behavior at extraction process in Tokai Reprocessing Plant. So we varied acidity and warmed up solution within the limit of operating parameter for second extraction cycle, and measured Np extracted.

Oral presentation

Control test of neptunium extraction at Tokai reprocessing plant

Nagaoka, Shinichi; Morimoto, Kazuyuki; Kitao, Takahiko; Obu, Tomoyuki; Kanamori, Sadamu; Omori, Eiichi

no journal, , 

40$$sim$$50% of neptunium (Np) was distributed to product stream in Tokai Reprocessing Plant (TRP) at present. We tried to increase acidity of second extraction cycle within available operating parameter, and by measuring neptunium concentration at outlet stage in second extraction cycle, we verified that 60$$sim$$70% of neptunium was distributed to product stream. Also we warmed up solutions in contactors of second extraction cycle within available operating parameter to make sure oxidation of neptunium on actual process, and we verified that 70% of neptunium was distributed to product stream. We confirmed that increasing acidity and warming up solutions was effective for Pu-U-Np co-extraction on the engineering scale reprocessing facility.

Oral presentation

Corrosion behavior of simulated HLW glass in seawater

Omori, Hiroyuki; Maeda, Toshikatsu; Mitsui, Seiichiro; Bamba, Tsunetaka

no journal, , 

no abstracts in English

29 (Records 1-20 displayed on this page)