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Sukegawa, Atsuhiko; Iida, Hiromasa*; Itoga, Toshio*; Okumura, Keisuke; Kai, Tetsuya; Konno, Chikara; Nakashima, Hiroshi; Nakamura, Takashi*; Ban, Shuichi*; Yashima, Hiroshi*; et al.
Hoshasen Shahei Handobukku; Kisohen, p.299 - 356, 2015/03
no abstracts in English
Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Nakajima, Motoki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Hayashi, Takumi; Yamanishi, Toshihiko; et al.
Fusion Engineering and Design, 89(7-8), p.1131 - 1136, 2014/10
Times Cited Count：21 Percentile：83.89(Nuclear Science & Technology)The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. Regarding the fabrication technology development using F82H, the fabrication of a real scale mockup of the back wall of TBM was completed. Also the assembling of the complete box structure of the TBM mockup and planning of the pressurization testing was studied. The development of advanced breeder and multiplier pebbles for higher chemical stability was performed for future DEMO blanket application. From the view point of TBM test result evaluation and DEMO blanket performance design, the development of the blanket tritium simulation technology, investigation of the TBM neutronics measurement technology and the evaluation of tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been performed.
Sato, Satoshi; Maegawa, Toshio*; Yoshimatsu, Kenji*; Sato, Koichi*; Nonaka, Akira*; Takakura, Kosuke; Ochiai, Kentaro; Konno, Chikara
Progress in Nuclear Science and Technology (Internet), 4, p.623 - 626, 2014/04
In the previous study, we developed a multi-layered concrete structure to reduce induced activity in concrete applied for neutron generation facilities such as a fusion reactor. This structure is composed of low activation concrete as the first layer, boron doped low activation concrete as the second layer and ordinary concrete as the third layer from the side of the neutron source. In this study, as an alternative of the boron doped low activation concrete we have developed the boron doped resin sheet with boron carbonate and resin to reduce the construction cost. The weight ratio of the boron carbonate to the resin is 0.75. The developed boron sheet has good flexibility and sufficient strength for repeated bending. DT neutron irradiation experiments for four multi-layered concrete structures with the boron sheet have been performed at the FNS (Fusion Neutronics Source) facility in JAEA in order to study shielding performance of the structures with the boron sheet. Structure-1 of about 30 cm in width, 30 cm in height and 50 cm in thickness is composed of low activation concrete of 20 cm in thickness as the first layer and ordinary concrete of 30 cm in thickness as the second layer. The boron sheet is inserted between the first and second layers. In Structure-2 one more boron sheet is inserted at the 10 cm depth from the surface of Structure-1. Structure-3 added one more boron sheet at 30 cm depth from the surface of Strucure-2. For comparison, Structure-4 has no boron sheet. The reaction rates were measured every 5 cm in depth with activation foils of gold and niobium. By inserting the boron sheet, the reaction rate of the gold generated by low energy neutrons decreases by a factor of about four. It is demonstrated that the multi-layered concrete structure with the boron sheet effectively reduces low energy neutrons.
Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Suzuki, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Yamanishi, Toshihiko; Hoshino, Tsuyoshi; Nakamichi, Masaru; et al.
Fusion Engineering and Design, 87(7-8), p.1363 - 1369, 2012/08
Times Cited Count：36 Percentile：92.04(Nuclear Science & Technology)The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. For the TBM testing and evaluation toward DEMO blanket, the module fabrication technology development by a candidate structural material, reduced activation martensitic/ferritic steel, F82H, is one of the most critical items from the viewpoint of realization of TBM testing in ITER. Fabrication of a real scale first wall, side walls, a breeder pebble bed box and assembling of the first wall and side walls have succeeded. Recently, the real scale partial mockup of the back wall was fabricated. The fabrication procedure of the back wall, whose thickness is up to 90 mm, was confirmed toward the fabrication of the real scale back wall by F82H. This paper overviews the recent achievements of the development of the WCCB TBM in Japan.
Sato, Satoshi; Maegawa, Toshio*; Yoshimatsu, Kenji*; Sato, Koichi*; Nonaka, Akira*; Takakura, Kosuke; Ochiai, Kentaro; Konno, Chikara
Journal of Nuclear Materials, 417(1-3), p.1131 - 1134, 2011/10
Times Cited Count：11 Percentile：63.92(Materials Science, Multidisciplinary)The multi-layered concrete structure has been developed to reduce induced activity in the concrete applied for neutron generation facilities such as a fusion reactor. The multi-layered concrete structure is composed of the low activation concrete as the first layer, the boron-doped low activation concrete as the second layer and the ordinary concrete as the third layer from the side of the neutron source. By applying the multi-layered concrete structure, the volume of the boron can drastically decrease compared with the monolithic boron-doped concrete. A 14 MeV neutron irradiation experiment with the multi-layered concrete structure mockups was performed at FNS and several reaction rates and induced activities in the mockups were measured. This experiment demonstrated that the multi-layered concrete effectively reduced low energy neutrons and induced activities.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：184 Percentile：99.45(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：9 Percentile：49.6(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
Okada, Koichi*; Kondo, Keitaro; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara; Okamoto, Atsushi*; Kobuchi, Takashi*; Kitajima, Sumio*; Sasao, Mamiko*
Journal of Plasma and Fusion Research SERIES, Vol.8, p.666 - 669, 2009/09
Measurement of fuel ion density ratio, 
/
, is required for burning control on ITER. The measured / ratio must be fed back in real time. A neutron measurement system to measure / should be operable at high counting rate. It is estimated that the number of emitted DT neutrons is 200 times higher than that of DD neutrons under the condition of ITER standard operation. A neutron measurement system was developed using a DT/DD generator, where DT neutrons are dominant and DD neutrons are contaminated slightly in the neutron beam. The measurement instrument was a TOF spectrometer. Signals originating from each neutron must be distinguished in order to measure the fuel ratio. We developed a circuit system with discrimination windows to distinguish each signal pulse, and DT and DD neutrons were measured separately and simultaneously with this system. The experimental result indicates a possibility that this system is suitable for measurement of fuel ion density ratio on ITER.
TiO
pebble bed for a test blanket module in JAEATanigawa, Hisashi; Hoshino, Tsuyoshi; Kawamura, Yoshinori; Nakamichi, Masaru; Ochiai, Kentaro; Akiba, Masato; Ando, Masami; Enoeda, Mikio; Ezato, Koichiro; Hayashi, Kimio; et al.
Nuclear Fusion, 49(5), p.055021_1 - 055021_6, 2009/05
Times Cited Count：23 Percentile：64.37(Physics, Fluids & Plasmas)This paper presents recent achievements of the research activities for the TBM being developed in JAEA, focusing on the pebble bed of the tritium breeder materials and tritium behaviour. For the breeder material, the chemical stability of LiTiO has been improved by LiO additives. In order to analyze the pebble bed behaviour, thermo-mechanical properties of the LiTiO pebble bed has been experimentally obtained. In order to verify nuclear properties of the pebble bed, the activation foil method has been proposed and a preliminary experiment has been conducted. For the tritium behaviour, the chemical densified coating method has been well developed and tritium recovery system has been modified taking account of the design change of the TBM.
Maki, Koichi*; Konno, Chikara
Nihon Genshiryoku Gakkai-Shi ATOMO
, 50(10), p.649 - 653, 2008/10
Neutrons produced by the fusion reaction generate secondary neutrons and 
-rays through interaction with materials of divertor, first wall and blanket. Target nuclei are recoiled by the interaction with these neutrons. At the micro level the recoiled nuclei disarray lattice arrangement and cause material damage if the recoil energy is larger than constraint energy of lattice. Here we will explain how the nuclear interactions change to heat and make radiation damage to materials.
Meigo, Shinichiro; Harada, Masahide; Konno, Chikara; Ikeda, Yujiro; Watanabe, Noboru; Sakamoto, Shinichi*; Muto, Suguru*; Miyake, Yasuhiro*; Nishiyama, Kusuo*; Shimomura, Koichiro*; et al.
JAERI-Conf 2001-002, p.314 - 324, 2001/03
no abstracts in English
Maki, Koichi*; Konno, Chikara; Maekawa, Fujio; Maekawa, Hiroshi; *; *
Fusion Technology, 36(1), p.52 - 61, 1999/07
no abstracts in English
Np transmutation characteristics with chemical analysis of neptunium dosimeter irradiated in "Joyo"Osaka, Masahiko; Koyama, Shinichi; Otsuka, Yuko; Mitsugashira, Toshiaki; Namekawa, Takashi; Konno, Koichi
PNC TN9410 98-020, 70 Pages, 1997/12
The purpose of this study is to evaluate transmutation characteristics such as dependence of Np transmutation rate to neutron energy spectrum and neutron fluences. Analysis of the Neptunium dosimeter, in which was irradiated in the experimental fast reactor "Joyo", was carried out by applying the technique for analysis of minor actinide nuclides in irradiated MOX fuel. It is necessary to remove Vanadium before analysis of Neptunium dosimeter because NpO
powder was enclosed in Neptunium dosimeter that was made of Vanadium capsule. The result of analysis and evaluations are as follows. (1)In order to recover Neptunium sample completely, sample was dissolved with capsule before removing the Vanadium from sample solution. Sample treatment method of whole capsule dissolution for chemical analysis of Neptunium dosimeter was established. (2)Np, Plutonium isotopes, 
Am and 
Cs in the dosimeter were analyzed using the method of whole capsule dissolution, alpha spectrometry, gamma spectrometry and isotopic dilution mass spectrometry. Transmutation rate of Np was calculated using the analyzed value. Tendency of transmutation rate was certified, which is higher fission ratio at the center and higher capture ratio at both upper and lower end. (3)Transmutation rate with error was evaluated by neutron fluences considering the neutron energy spectrum, and calculated value by "MAGI" code was agreed well with analysis value. Dependence of transmutation rate of Np to neutron energy spectrum was certified.
Koyama, Shinichi; Osaka, Masahiko; Mitsugashira, Toshiaki; Konno, Koichi; Kajitani, Yukio
PNC TN9410 97-054, 44 Pages, 1997/04
For analysis of a small quantity of americium, it is necessary to separate from curium which has similar chemical property. As a chemical separation method for americium, and curium, the oxidation of americium with pentavalent bismuth and subsequent co-precipitation of trivalent curium with BIPO
were applied to analyze americium in irradiated MOX fuels which contained about 3Owt% plutonium and 0.9wt% Am before irradiation and were irradiated up to 26.2GWd/t in the experimental fast reactor Joyo. The purpose of this study is to measure isotopic ratio of americium and to evaluate the change of isotopic ratio with irradiation. Following results are obtained in this study, (1)The isotopic ratio of americium (Am, 
Am and 
Am) can be analyzed in the MOX fuels by isolating americium. The isotopic ratio of 
Am and Am increases up to 0.62at% and 0.82at% at maximum burnup, respectively. (2)The results of isotopic analysis indicates that the contents of Am decreases, whereas Am, Am increase linearly with increasing burnup.
Osaka, Masahiko; Koyama, Shinichi; Otsuka, Yuko; Mitsugashira, Toshiaki; Konno, Koichi; Kajitani, Yukio
PNC TN9410 96-297, 79 Pages, 1996/11
As a part of evaluation of irradiation behavior and burnup characteristics of MA nuclides such as Np, Am and Cm in MA containing MOX fuel, we are studying the quantitative analysis techniques for MA nuclides in irradiated fuel. In this study, we studied the mutual separation method for Am and Cm to establish the analysis method for Am and Cm following Np analysis by alpha spectrometry. The measurements of Am and Cm are difficult to analyze quantitatively because the amounts of some nuclides are too small and the number of nuclides are large, whose energies of the alpha radioactive rays are almost same. Therefore we selected to analyze the trace amount of Am and Cm isotopes using mass spectrometry, and have studied the techniques for mutual separation of Am and Cm using oxidation method of Am by NaBiO
for standard samples. We have also evaluated the availability of this method for irradiated fuel. Results are as follows. (1)Through the mutual separation tests, we have found the most suitable conditions for separation of both Am and Cm from each other element. The method obtaining Am which contains no Cm is used water for precipitation washing solution, containing Cm is achicved that the remaining ratio of Am (ratio of radioactivity of Am/
Cm against before separation) were reduced less than 1/10 for Cm. (2)Applying of this method to irradiated fuel, the coordinate remaining ratio and the chemical yield of Am and Cm were almost same as them in the separation tests. This method to apply various irradiated MOX Fuel is therefore possible. (3)The isotope ratio Am, Am and Am measured by mass spectrometry, which could not be analyzed by radioactive ray spectrometry causing less than detection limit, were 98.55% : 0.62% : 0.83%. We also measured zero of the mass number of 240 and 244 on the specimens and then certified no contamination of Cm to Am.
Am content and evaluation of burnup dependence in Am containing MOX fuel pinKoyama, Shinichi; Osaka, Masahiko; Otsuka, Yuko; Konno, Koichi; Kajitani, Yukio; Mitsugashira, Toshiaki
PNC TN9410 96-301, 61 Pages, 1996/10
We are studying quantitative analysis of Minor Actinides (Np, Am, Cm) in irradiated fuels as a part of the PNC research project for advanced nuclear fuel recycle system. In alpha-gamma section, irradiation behavior of MOX fuel and burning characteristic evaluation research of the MA nuclide which contain the minor actinide species are carrying out. We measured Am content of the MOX fuel pin which contained Am of about 0.9wt% before irradiation and were irradiated up to 26.2GWd/t in the JOYO reactor. The results are as follows. Burn-up dependence of the Am content in this samples was not observed. The Am content showed the fixed value of about 1% in the range from 0 to 28GWd/t. This reason is assumed that Am produced by 
-decay of Pu for cooling times between each cycles valances it in disappearance under irradiated in JOYO based on the calculated value by ORIGEN-II code.
Nakakawa, Masayuki; Kosako, Kazuaki*; Mori, Takamasa; Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; *; et al.
JAERI-M 92-183, 106 Pages, 1992/12
no abstracts in English
Oyama, Yukio; Konno, Chikara; Ikeda, Yujiro; Yamaguchi, Seiya*; Tsuda, Koichi*; Maekawa, Hiroshi; *; Kosako, Kazuaki*; Nakakawa, Masayuki; Mori, Takamasa; et al.
JAERI-M 92-182, 151 Pages, 1992/12
no abstracts in English
Okada, Koichi; Kondo, Keitaro; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara; Nishitani, Takeo; Nomura, Ken*; Okamoto, Atsushi*; Kitajima, Sumio*; Sasao, Mamiko*
no journal, ,
no abstracts in English
Okada, Koichi*; Kondo, Keitaro; Ochiai, Kentaro; Sato, Satoshi; Konno, Chikara; Okamoto, Atsushi*; Kobuchi, Takashi*; Kitajima, Sumio*; Sasao, Mamiko*
no journal, ,
no abstracts in English
