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Journal Articles

Corrosion monitoring in humidity-controlled environment simulating gamma ray irradiation

Omori, Atsushi*; Akiyama, Eiji*; Abe, Hiroshi*; Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; et al.

Zairyo To Kankyo, 69(4), p.107 - 111, 2020/04

To evaluate the effect of oxidants, which are formed by radiolysis of water under gamma ray irradiation, on the corrosion of a carbon steel in humid environment, ozone was introduced as a model oxidant in to humidity-controlled air at 50$$^{circ}$$C in a thermo-hygrostat chamber. Corrosion monitoring was performed by using an Atmospheric Corrosion Monitor-type (ACM) sensor consisting of a carbon steel anode and an Ag cathode. The output current of the ACM sensor was increased with the increase in relative humidity and it was obviously increased with the increase in the introduced ozone concentration at each relative humidity. The results indicate that ozone accelerates the corrosion of the carbon steel. The effect of ozone on the corrosion acceleration is attributed to the fast reduction reaction and fast dissolution reaction in to water compared to that of oxygen.

Journal Articles

New result in the production and decay of an isotope, $$^{278}$$113 of the 113th element

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.

Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10

 Times Cited Count:133 Percentile:2.36(Physics, Multidisciplinary)

An isotope of the 113th element, $$^{278}$$113, was produced in a nuclear reaction with a $$^{70}$$Zn beam on a $$^{209}$$Bi target. We observed six consecutive $$alpha$$ decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of $$^{262}$$Db and $$^{258}$$Lr both in decay energies and decay times. This indicates that the present decay chain consisted of $$^{278}$$113, $$^{274}$$Rg (Z = 111), $$^{270}$$Mt (Z = 109), $$^{266}$$Bh (Z = 107), $$^{262}$$Db (Z = 105), and $$^{258}$$Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope $$^{278}$$113, of the 113th element.

Journal Articles

Attempt to produce the 3rd chain of $$^{278}$$113

Morimoto, Koji*; Morita, Kosuke*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.

RIKEN Accelerator Progress Report, Vol.42, P. 15, 2009/00

In 2003-2007, we had performed an experiment to synthesize an element 113 by a $$^{209}$$Bi$$+$$ $$^{70}$$Zn reaction using a gas-filled recoil ion separator (GARIS) at RIKEN Nishina-Center. In a total of 241 days of net irradiation time experiment, two decay chains were observed and assigned from an isotope $$^{278}$$113. The cross section of the $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113 reaction was determined to be 31$$^{+40}_{-20}$$ fb at that time. In order to increase the statistics of the decay property, we continued to produce more decay chains. The experiment was carried out from January 7 to March 31, 2008. The experimental conditions were identical to those used in the previous experiment. $$^{70}$$Zn ion beam of 353 MeV was extracted from RILAC. The net irradiation time was 83 days and the total dose of $$^{70}$$Zn was 2.28$$times10^{19}$$. In the present expriment any candidate of $$^{278}$$113 was not observed. Then combining the results of the present and previous experiments, the production cross section of $$^{278}$$113 was determined to be 22$$^{+29}_{-19}$$ fb.

Journal Articles

Hexafluoro complex of rutherfordium in mixed HF/HNO$$_{3}$$ solutions

Toyoshima, Atsushi; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Akiyama, Kazuhiko*; Goto, Shinichi*; Ishii, Yasuo; Nishinaka, Ichiro; Sato, Tetsuya; Nagame, Yuichiro; et al.

Radiochimica Acta, 96(3), p.125 - 134, 2008/03

 Times Cited Count:26 Percentile:12.89(Chemistry, Inorganic & Nuclear)

Formation of an anionic fluoride-complex of element 104, rutherfordium (Rf) produced in the $$^{248}$$Cm($$^{18}$$O,5n)$$^{261}$$Rf reaction was studied by an anion-exchange method based on an atom-at-a-time scale. It was found that the hexafluoro complex of Rf, [RfF$$_{6}$$]$$^{2-}$$, was formed in the studied fluoride ion concentrations of 0.0005 - 0.013 M. Formation of [RfF$$_{6}$$]$$^{2-}$$ was significantly different from that of the homologues Zr and Hf, [ZrF$$_{6}$$]$$^{2-}$$ and [HfF$$_{6}$$]$$^{2-}$$; the evaluated formation constant of [RfF$$_{6}$$]$$^{2-}$$ is at least one-order of magnitude smaller than those of [ZrF$$_{6}$$]$$^{2-}$$ and [HfF$$_{6}$$]$$^{2-}$$.

Journal Articles

Experiment on synthesis of an isotope $$^{277}$$112 by $$^{208}$$Pb + $$^{70}$$Zn reaction

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.

Journal of the Physical Society of Japan, 76(4), p.043201_1 - 043201_5, 2007/04

 Times Cited Count:125 Percentile:4.17(Physics, Multidisciplinary)

The production and decay of $$^{277}$$112 has been investigated using a gas-filled recoil ion separator in irradiations of $$^{208}$$Pb targets with $$^{70}$$Zn beam at 349.5 MeV. We have observed two $$alpha$$-decay chains that can be assigned to subsequent decays from $$^{277}$$112 produced in the 208 Pb($$^{70}$$Zn,n) reaction. After emitting four consecutive $$alpha$$-particles, the both chains ended by spontaneous fission decays of $$^{261}$$Rf and decay energies and decay times of the both chains obtained in the present work agree well with those reported by a group at Gesellschaft f$"u$r Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of $$^{277}$$112 and its $$alpha$$-decay products $$^{273}$$Ds reported previously.

Journal Articles

Observation of second decay chain from $$^{278}$$113

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kikunaga, Hidetoshi*; et al.

Journal of the Physical Society of Japan, 76(4), p.045001_1 - 045001_2, 2007/04

 Times Cited Count:175 Percentile:2.48(Physics, Multidisciplinary)

The production and decay of $$^{278}$$113 has been investigated using a gas-filled recoil ion separator in irradiations of $$^{209}$$Bi targets with $$^{70}$$Zn beam at 353 MeV. We have observed one $$alpha$$-decay chain that can be assigned to subsequent decays from $$^{278}$$113 produced in the $$^{209}$$Bi($$^{70}$$Zn,n) reaction. After emitting four consecutive $$alpha$$-particles, the both chains ended by spontaneous fission decays of $$^{262}$$Db and decay energies and decay times of the both chains obtained in the present work agree well with those reported by our group in 2004. The present result gives the first clear confirmation of the discovery of $$^{278}$$113 and its $$alpha$$-decay products $$^{274}$$Rg reported previously.

Journal Articles

Experiments on synthesis of the heaviest element at RIKEN

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Kikunaga, Hidetoshi*; et al.

AIP Conference Proceedings 891, p.3 - 9, 2007/03

A series of experiments studying the productions and their decays of the heaviest elements have been performed by using a gas-filled recoil separator GARIS at RIKEN. Results on the isotope of the 112th element, $$^{277}$$112, and on that of the 113th element, $$^{278}$$113, are reviewed. Two decay chains which are assigned to be ones originating from the isotope $$^{277}$$112 were observed in the $$^{208}$$Pb($$^{70}$$Zn, n) reaction. The results provide a confirmation of the production and decay of the isotope $$^{277}$$112 reported by a research group at GSI, Germany, produced via the same reaction by using a velocity filter. Two decay chains, both consisted of four consecutive alpha decays followed by a spontaneous fission, were observed also in the reaction $$^{209}$$Bi($$^{70}$$Zn, n). Those are assigned to be the convincing candidate events of the isotope of the 113th element, $$^{278}$$113, and its daughter nuclei. $$^{274}$$Rg, $$^{270}$$Mt, $$^{266}$$Bh, and $$^{262}$$Db.

Journal Articles

Extraction behavior of rutherfordium into tributylphosphate from hydrochloric acid

Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Tome, Hayato; Sato, Tetsuya; Nishinaka, Ichiro; Ichikawa, Takatoshi; Ichikawa, Shinichi; et al.

Radiochimica Acta, 95(1), p.1 - 6, 2007/01

 Times Cited Count:15 Percentile:25.74(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Experiment on the synthesis of element 113 in the reaction $$^{209}$$Bi($$^{70}$$Zn,n)$$^{278}$$113

Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Koura, Hiroyuki; et al.

Journal of the Physical Society of Japan, 73(10), p.2593 - 2596, 2004/10

 Times Cited Count:414 Percentile:0.81(Physics, Multidisciplinary)

The isotope of the 113th element, $$^{278}$$113, and its daughter nuclei, $$^{274}$$111 and $$^{270}$$Mt, were obserbed, for the first time, in the $$^{209}$$Bi + $$^{70}$$Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.6$$times$$10$$^{19}$$. The production cross section of $$^{278}$$113 is deduced to be $$57^{+154}_{-47}$$ fb ($$10^{-39}$$ cm$$^2$$).

JAEA Reports

Feasibility study on application of superconductivity /magnetic fluid technologies to FBRs

Akiyama, Mamoru*; Miyazaki, Keiji*; Takeshita, Toshihide*

PNC-TJ2360 88-001, 222 Pages, 1988/03

PNC-TJ2360-88-001.pdf:6.14MB

no abstracts in English

Oral presentation

Chloride complex formation of Rf in HCl and CH$$_{3}$$OH mixed solution

Tsukada, Kazuaki; Toyoshima, Atsushi; Haba, Hiromitsu*; Asai, Masato; Akiyama, Kazuhiko*; Ishii, Yasuo; Tome, Hayato; Nishinaka, Ichiro; Sato, Tetsuya; Ichikawa, Shinichi; et al.

no journal, , 

no abstracts in English

Oral presentation

Training program of the surface contamination monitoring at the Tokai reprocessing plant

Takahata, Eiji; Iijima, Nobuo; Yamashita, Tomoyuki; Akiyama, Kiyomitsu

no journal, , 

A training program of the body surface contamination at the Tokai Reprocessing Plant is introduced. This program takes consideration with low-level measurement of alpha and beta ($$gamma$$) contamination in workplace. The training effect of this program is evaluated by actual survey tests.

Oral presentation

Summary of development of corrosion database under radiation environment

Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

Risk of corrosion degradation for plant materials in Fukushima-Daiichi Nuclear Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure. We will build the corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion in this project. In this presentation, we will describe summary of this project.

Oral presentation

Development of corrosion database under radiation environment

Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

Since risk of corrosion degradation for plant materials in Fukushima Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we will describe the overview of this research project.

Oral presentation

Development of corrosion database under radiation environment, 2; Development of data set and database for radiolysis calculation

Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

no abstracts in English

Oral presentation

Development of corrosion database under radiation environment, 1; Overview

Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we describe the overview of this project.

Oral presentation

Development of corrosion database under radiation environment, 3; Construction of corrosion test environment in gamma-ray irradiation and Influence of gamma irradiation on de-passivation of carbon steel

Sato, Tomonori; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Inoue, Hiroyuki*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*; Hata, Kuniki; Kaji, Yoshiyuki

no journal, , 

To develop the database for the corrosion under irradiation, the experimental evaluation for the corrosion under irradiation is necessary. So, the corrosion test environment under irradiation with controlling pH, temperature dissolved O$$_{2}$$ concentration and ion concentration was constructed in Takasaki Research center, QST. And, influence of gamma irradiation on de-passivation of carbon steel was evaluated. The map for corrosion property of carbon steel in the borate and chloride ions containing water was created based on the experimental data. The corrosion behavior changes with the concentration of borate.

Oral presentation

Development of corrosion database in specific environment

Sato, Tomonori; Hata, Kuniki; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion.

Oral presentation

Development of corrosion database under radiation environment, 2; Development of radiolysis dataset for contaminated stagnant water

Hata, Kuniki; Sato, Tomonori; Kaji, Yoshiyuki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

no abstracts in English

Oral presentation

Development of corrosion database under radiation environment, 1; Overview

Kaji, Yoshiyuki; Sato, Tomonori; Hata, Kuniki; Inoue, Hiroyuki*; Taguchi, Mitsumasa*; Seito, Hajime*; Tada, Eiji*; Abe, Hiroshi*; Akiyama, Eiji*; Suzuki, Shunichi*

no journal, , 

Since risk of corrosion degradation for plant materials in Fukushima-Daiichi Power Plant (1F) site have been increasing with time duration and/or environmental changes by decommissioning procedure, we will build a corrosion and radiolysis database in irradiated condition including estimating data area for 1F corrosion. In this presentation, we describe the overview of this project in 2018 fiscal year.

22 (Records 1-20 displayed on this page)