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JAEA Reports

Report on cause investigation and countermeasure of leakage trace from the drum

Shimomura, Yusuke; Sato, Takuya; Fukui, Yasutaka; Kudo, Kenji; Yoshioka, Tatsuji

JAEA-Review 2018-023, 220 Pages, 2019/01

JAEA-Review-2018-023.pdf:15.6MB

On September 11, 2015, leaky traces of bituminized wastes were confirmed from four drums filled with bituminization in waste packages storage yard (II) of waste management facility in Oarai Research and Development Center. Moreover, even after the subsequent investigation, a leakage trace was found from one bituminous drum on November 10, 2015. Furthermore, on December 2, 2015, there was no a leakage trace in one bituminous drum, however the upper lid was found to be intensely corroded. To investigate the causes and the countermeasures for leakages of bituminized wastes from the drums, we have set up a Work Group to investigate the causes and the countermeasures to leakage traces from the drums. This report is based on "Report on Cause Investigation and Countermeasure of Leakage Trace from the Drum" summarized by this working group, the report was reconstructed including the contents clarified in the subsequent document investigation.

Journal Articles

Complex chemistry with complex compounds

Eichler, R.*; Asai, Masato; Brand, H.*; Chiera, N. M.*; Di Nitto, A.*; Dressler, R.*; D$"u$llmann, Ch. E.*; Even, J.*; Fangli, F.*; Goetz, M.*; et al.

EPJ Web of Conferences (Internet), 131, p.07005_1 - 07005_7, 2016/12

 Times Cited Count:1 Percentile:45.1

In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the productions and investigations of fragile single molecular species of superheavy elements. The latest highlight is the formation of very volatile hexacarbonyl compound of element 106, Sg(CO)$$_{6}$$. Following this success, second-generation experiments were performed to measure the first bond dissociation energy between the central metal atom and the surrounding ligand. The method using a tubular decomposition reactor was developed and successfully applied to short-lived Mo(CO)$$_{6}$$, W(CO)$$_{6}$$, and Sg(CO)$$_{6}$$.

Journal Articles

Decomposition studies of group 6 hexacarbonyl complexes, 1; Production and decomposition of Mo(CO)$$_6$$ and W(CO)$$_6$$

Usoltsev, I.*; Eichler, R.*; Wang, Y.*; Even, J.*; Yakushev, A.*; Haba, Hiromitsu*; Asai, Masato; Brand, H.*; Di Nitto, A.*; D$"u$llmann, Ch. E.*; et al.

Radiochimica Acta, 104(3), p.141 - 151, 2016/03

 Times Cited Count:13 Percentile:8.66(Chemistry, Inorganic & Nuclear)

Conditions of the production and decomposition of hexacarbonyl complexes of short-lived Mo and W isotopes were investigated to study thermal stability of the heaviest group 6 hexacarbonyl complex Sg(CO)$$_6$$. A tubular flow reactor was tested to decompose the hexacarbonyl complexes and to extract the first bond dissociation energies. A silver was found to be the most appropriate reaction surface to study the decomposition of the group 6 hexacarbonyl. It was found that the surface temperature at which the decomposition occurred was correlated to the first bond dissociation energy of Mo(CO)$$_6$$ and W(CO)$$_6$$, indicating that the first bond dissociation energy of Sg(CO)$$_6$$ could be determined with this technique.

Journal Articles

In situ synthesis of volatile carbonyl complexes with short-lived nuclides

Even, J.*; Ackermann, D.*; Asai, Masato; Block, M.*; Brand, H.*; Di Nitto, A.*; D$"u$llmann, Ch. E.*; Eichler, R.*; Fan, F.*; Haba, Hiromitsu*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 303(3), p.2457 - 2466, 2015/03

 Times Cited Count:8 Percentile:25.61(Chemistry, Analytical)

Rapid In situ synthesis of metal carbonyl complexes has been demonstrated using short-lived isotopes produced in nuclear fission and fusion reactions. The short-lived isotopes with high recoil energy directly react with carbon-monoxides and form carbonyl complexes. Only highly volatile complexes were fast transported in a gas stream to counting and chemistry devices. Short-lived Mo, Tc, Ru, Rh, W, Re, Os, and Ir were found to form volatile carbonyl complexes, while no volataile complex of Hf and Ta were detected. This technique has been applied to a chemical investigation of the superheavy element Sg (atomic number 106), and will be applicable to various fields of nuclear science with short-lived transition metal isotopes.

Journal Articles

Synthesis and detection of a Seaborgium carbonyl complex

Even, J.*; Yakushev, A.*; D$"u$llmann, Ch. E.*; Haba, Hiromitsu*; Asai, Masato; Sato, Tetsuya; Brand, H.*; Di Nitto, A.*; Eichler, R.*; Fan, F. L.*; et al.

Science, 345(6203), p.1491 - 1493, 2014/09

 Times Cited Count:41 Percentile:17.1(Multidisciplinary Sciences)

A new superheavy element complex, a seaborgium carbonyl, has been successfully synthesized, and its adsorption property has been studied using a cryo-thermochromatography and $$alpha$$-detection apparatus COMPACT. Nuclear reaction products of short-lived $$^{265}$$Sg preseparated with a gas-filled recoil ion separator GARIS at RIKEN were directly injected into a gas cell filled with He/CO mixture gas, and chemical reaction products of volatile carbonyl complexes were trasported to COMPACT. The Sg carbonyl complex detected with COMPACT was found to be very volatile with adsorption enthalpy of $$-$$50 kJ/mol, from which we have concluded that this complex should be a Sg hexacarbonyl Sg(CO)$$_{6}$$. This is the first synthesis of organometallic compounds of transactinide elements for which only simple inorganic comounds have been synthesized so far.

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:12.33(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

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:24.99(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Fabrication of 8Cr-2W ferritic steel tile for reduction in toroidal magnetic field ripple on JT-60U

Kudo, Yusuke; Sawai, Tomotsugu; Sakurai, Shinji; Masaki, Kei; Suzuki, Yutaka; Sasajima, Tadayuki; Hayashi, Takao; Takahashi, Ryukichi*; Honda, Masao; Jitsukawa, Shiro; et al.

Journal of the Korean Physical Society, 49(96), p.S297 - S301, 2006/12

Installation of ferritic steel tiles was proposed in JT-60U to reduce the toroidal magnetic field ripple and to improve the fast ion loss, which degrades heating efficiency and increases heat load on plasma facing component under large volume plasma operations. We selected a 8Cr-2W-0.2V ferritic steel with the cost-effectiveness, in which concentration limits of activation elements in F82H were relaxed because of the less number of neutron generations from deuterium operations on JT-60U. The fabricated ferritic steel has clear tempered martensitic microstructure, and sufficient magnetic and mechanical properties. The saturated magnetization was estimated to 1.7 Tesla at 573 K, lower than expected, but effectiveness in JT-60U was confirmed by numerical analyses. To research the effect of material conditions, such as microstructure and heat treatment, on saturated magnetization of the ferritic steel based on 8-9Cr is important for the future fusion reactors which will be planned to install the ferritic steel as the in-vessel components.

Journal Articles

Overview of national centralized tokamak program; Mission, design and strategy to contribute ITER and DEMO

Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.

Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12

To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.

Journal Articles

Overview of the national centralized tokamak programme

Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.

Nuclear Fusion, 46(3), p.S29 - S38, 2006/03

 Times Cited Count:13 Percentile:53.63(Physics, Fluids & Plasmas)

The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.

Journal Articles

Engineering design and control scenario for steady-state high-beta operation in national centralized tokamak

Tsuchiya, Katsuhiko; Akiba, Masato; Azechi, Hiroshi*; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; et al.

Fusion Engineering and Design, 81(8-14), p.1599 - 1605, 2006/02

 Times Cited Count:1 Percentile:89.11(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Design study of fusion DEMO plant at JAERI

Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Sato, Masayasu; Isono, Takaaki; Sakurai, Shinji; Nakamura, Hirofumi; Sato, Satoshi; Suzuki, Satoshi; Ando, Masami; et al.

Fusion Engineering and Design, 81(8-14), p.1151 - 1158, 2006/02

 Times Cited Count:108 Percentile:0.71(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Fracture mechanics analysis including the butt joint geometry for the superconducting conductor conduit of the national centralized tokamak

Takahashi, Hiroyuki*; Kudo, Yusuke; Tsuchiya, Katsuhiko; Kizu, Kaname; Ando, Toshinari*; Matsukawa, Makoto; Tamai, Hiroshi; Miura, Yukitoshi

Fusion Engineering and Design, 81(8-14), p.1005 - 1011, 2006/02

 Times Cited Count:2 Percentile:80.97(Nuclear Science & Technology)

This paper presents dependence of the stress intensity factor, around the defect in the butt joint welding of a superconducting conductor conduit, on a geometrical factor estimated by fracture mechanics analysis. The stress intensity factor can be estimated by the Newman-Raju equation about CICC section, but the effect of the difference between the geometry assumed in the equation and CICC has not been clarified yet. Therefore, the three-dimensional finite element method (3D-FEM) is performed to estimate the geometrical factor. As a result, the Newman-Raju equation is considered to be available for the assessment of the fracture toughness of the conduit of rectangular shape because the maximum stress intensity factor by 3-D FEM is only 3% larger than that by the Newman-Raju equation in the maximum postulated defect.

Journal Articles

Design study of national centralized tokamak facility for the demonstration of steady state high-$$beta$$ plasma operation

Tamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.

Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12

 Times Cited Count:15 Percentile:50.17(Physics, Fluids & Plasmas)

Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.

Journal Articles

On-line reactor monitoring with neural network for RSG-GAS

Nabeshima, Kunihiko; Kurnianto, K.*; Surbakti, T.*; Pinem, Surian*; Subekti, M.*; Minakuchi, Yusuke*; Kudo, Kazuhiko*

Proceedings of ICSC Congress on Computational Intelligence Methods and Applications (CIMA'2005) (CD-ROM), 4 Pages, 2005/12

The ANNOMA (Artificial Neural Network of Monitoring Aids) system is applied to the condition monitoring and signal validation of Multi Purpose Reactor in Indonesia. The feedforward neural network in auto-associative mode learns reactor's normal operational data, and models the reactor dynamics during the initial learning. The basic principle of the anomaly detection is to monitor the deviation between the process signals measured from the actual reactor and the corresponding values predicted by the reactor model, i.e., the neural networks. The pattern of the deviation at each signal is utilized for the identification of anomaly, e.g. sensor failure or system fault. The on-line test results showed that the neural network successfully monitored the reactor status during power increasing and steady state operation in real-time.

Journal Articles

Fatigue assessment of the ITER TF coil case based on JJ1 fatigue tests

Hamada, Kazuya; Nakajima, Hideo; Takano, Katsutoshi*; Kudo, Yusuke; Tsutsumi, Fumiaki*; Okuno, Kiyoshi; Jong, C.*

Fusion Engineering and Design, 75-79, p.87 - 91, 2005/11

 Times Cited Count:8 Percentile:46.33(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Chemical studies on rutherfordium (Rf) at JAERI

Nagame, Yuichiro; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Akiyama, Kazuhiko; Ishii, Yasuo; Sato, Tetsuya; Hirata, Masaru; Nishinaka, Ichiro; Ichikawa, Shinichi; et al.

Radiochimica Acta, 93(9-10), p.519 - 526, 2005/00

 Times Cited Count:28 Percentile:11.21(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Mechanical tests on the welding part of SS316LN after heat treatment for Nb$$_{3}$$Sn superconducting conductor

Kudo, Yusuke; Sakasai, Akira; Hamada, Kazuya; Takano, Katsutoshi*; Nakajima, Hideo; Okuno, Kiyoshi; Matsukawa, Makoto; Tamai, Hiroshi; Ishida, Shinichi

Journal of Nuclear Materials, 329-333(Part1), p.634 - 638, 2004/08

 Times Cited Count:1 Percentile:89.17(Materials Science, Multidisciplinary)

Japan Atomic Energy Research Institute (JAERI) has a plan to construct a tokamak fusion device called JT-60SC in which superconducting magnet system will be used. The objectives of this study are to clarify applicability of conventional austenitic stainless steel wire for the SS316LN to the conduit material of the Nb3Sn cable-in-conduit conductor for the central solenoid (CS) of JT-60SC. Tensile properties, fracture toughness and fatigue crack growth rate of both as-weld and aged (923 K $$times$$ 240 hours) weld metals were evaluated at 4 K. The measured tensile properties of aged weld metal satisfied the requirement of JT-60SC. Fatigue crack growth property was enough to ensure the required operation cycles of 9.0 $$times$$ 10e4. However, fracture toughness of aged weld metal could not be validated due to unstable crack extension. It was concluded that improvement of fracture toughness after aging was required to ensure the structural integrity of the CS conduit.

Journal Articles

Advanced fusion technologies developed for JT-60 superconducting Tokamak

Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.

Nuclear Fusion, 44(2), p.329 - 334, 2004/02

no abstracts in English

Journal Articles

Advanced fusion technologies developed for JT-60 superconducting Tokamak

Sakasai, Akira; Ishida, Shinichi; Matsukawa, Makoto; Akino, Noboru; Ando, Toshinari*; Arai, Takashi; Ezato, Koichiro; Hamada, Kazuya; Ichige, Hisashi; Isono, Takaaki; et al.

Nuclear Fusion, 44(2), p.329 - 334, 2004/02

 Times Cited Count:7 Percentile:74.05(Physics, Fluids & Plasmas)

no abstracts in English

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