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Zaima, Naoki; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Nakashima, Shinichi; Yoshida, Hideaki; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Takase, Misao; Haruyama, Mitsuo
no journal, ,
We have just started to operate the extremely small accelerator for the purpose of the neutron assay against the uranium bearing wastes drums, so called active assay of NDA, which is an extension of the passive assay system, NWAS at Ningyo-toge Environmental Technical Center. The purposes of both are the improvements for measurements methodology and the accuracy of safe-guards data by determining uranium mass. The systems are composed of the (d,T) accelerator as a generator of 14 MeV neutrons, and Helium-3 proportional counters which detect the neutrons derived from U-235 fissions. Uranium mass are to be determined through detecting and analyzing fission neutrons, FNDI (Fast Neutron Direct Interrogation) method, which had been developed by the Nuclear Science and Engineering Directorate of JAEA. After configuration systems we had carried out the basic tests, and had validated the high sensitivity neutron detection and high precision determination.
Komeda, Masao; Ozu, Akira; Haruyama, Mitsuo; Takase, Misao; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Zaima, Naoki; Nakashima, Shinichi
no journal, ,
no abstracts in English
Arai, Yusuke*; Honda, Teruyuki*; Iwatsuki, Teruki; Nomura, Masao*
no journal, ,
The occurrence of rare earth elements in alteration rock and fault of Toki granite was observed to infer the migration process of minor actinides. The light rare earth elements concentrated in alteration rock and fault compared to fresh rock due to precipitation as a secondary mineral and adsorption onto clay minerals. This suggests the possibility of retardation of minor actinides by alteration minerals.
Sakasai, Kaoru; Nakamura, Tatsuya; To, Kentaro; Suzuki, Hiroyuki; Ozu, Akira; Ebine, Masumi; Birumachi, Atsushi; Takase, Misao; Kurata, Noritaka; Yoshino, Seiji; et al.
no journal, ,
We have developed the neutron-sensitive scintillator neutron counter for nuclear safeguards. The detector is made based on the scintillator detector technology developed long in the J-PARC/MLF. The detector is comprised of the ZnS/B
O
ceramic scintillator, rectangular shaped light guide and photomultiplier tubes. The detector performances including detector efficiency and its incident position dependence and 
-ray sensitivity are presented in detail.
Birumachi, Atsushi; Ebine, Masumi; Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Honda, Katsunori; Soyama, Kazuhiko; Katagiri, Masaki*
no journal, ,
no abstracts in English
Ebine, Masumi; Birumachi, Atsushi; Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Honda, Katsunori; Soyama, Kazuhiko; Katagiri, Masaki*
no journal, ,
no abstracts in English
Nakamura, Tatsuya; To, Kentaro; Sakasai, Kaoru; Honda, Katsunori; Ebine, Masumi; Birumachi, Atsushi; Soyama, Kazuhiko; Katagiri, Masaki*
no journal, ,
We have initiated the development of the two-dimensional scintillator neutron detector for a protein diffractometer. The diffractometer is planned to be built in the J-PARC/MLF near future. We propose the detector designs that could fulfill the required specification for the instrument together with some basic experimental results.
Otsuka, Noriaki; Yamamoto, Keiichi; Takeuchi, Tomoaki; Kimura, Nobuaki; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Nakajima, Ken*; Homma, Ryohei*
no journal, ,
no abstracts in English
Nozawa, Takashi; Asakura, Yuki*; Koyama, Akira*; Tanigawa, Hiroyasu
no journal, ,
no abstracts in English
Iwai, Yasunori; Sato, Katsumi; Kubo, Hitoshi*; Oshima, Yusuke*; Noguchi, Hiroshi*; Taniuchi, Junichi*
no journal, ,
Taking an accident such as loss of electric power into consideration, a hydrophobic catalyst, over which tritium and oxygen can react efficiently at room temperature, will contribute greatly to the fusion safety. Japan Atomic Energy Agency and Tanaka Kikinzoku Kogyo K.K. has jointly developed the hydrophobic platinum catalyst TKK-KNOITS for the oxidation of very thin tritium at room temperature. The overall reaction rate constant at room temperature for TKK-KNOITS was much larger than that for TKK-H1P, previously reported. The volume of catalytic reactor can be significantly reduced when the reactor is packed with TKK-KNOITS.
Takahara, Shogo; Iijima, Masashi; Hidaka, Akihide; Homma, Toshimitsu
no journal, ,
no abstracts in English
Namatame, Toshihiro; Masui, Kenji; Takahashi, Masatomi; Sato, Takehiko; Fujimoto, Ikuo; Tanaka, Yukiyoshi
no journal, ,
no abstracts in English
Yamashita, Susumu; Takase, Kazuyuki; Yoshida, Hiroyuki
no journal, ,
In the Fukushima accidents, fuel assemblies which were installed in the reactors were reached a high temperature by stop of the core cooling system with a power station black-out. As a result, it is considered that the core degradation has been introduced because the melting of the fuel rods occurred and the melting behavior was expanded. In order to elucidate a progress of the melting phenomena in the reactor core, a numerical simulation code which can be precisely evaluated the melting phenomena is required. Then, the melting behavior of the fuel assemblies in the reactor core was analyzed numerically using the three-dimensional multi-phase thermal-hydraulic simulation code. In the presentation, we report that effects of heated molten material on core internals by means of the simulation code.
Shimada, Kazumasa
no journal, ,
Cancer risk assessment of radiation is used a dose response based on epidemiology data and have not been reflected a cancer mechanism for example cell mutation. We know that cell mutation ratios are changed by radiation doses. Ordinary cancer model can not estimate cell mutation and apoptosis parameters separately from epidemiology data. Then, I set the goal to improve the assessment of cancer risk of radiation using cancer model reflected cell experiments. In this research, I used the State Space Model which is one of the Bayesian model to combine the epidemiology data and cancer model considering cell mutation and to estimate mutation parameters from the epidemiology data of atomic bomb survivor.
Kitamura, Akira; Doi, Reisuke; Yoshida, Yasushi*
no journal, ,
We updated JAEA thermodynamic database (JAEA-TDB). This critical review specifically addressed thermodynamic data for the solid oxides and hydroxido complexes of tin and some other elements. Use of the Br
nsted-Guggenheim-Scatchard Model (SIT) for ionic strength corrections was applied to the PHREEQC database.
Tagami, Hirotaka; Suzuki, Toru; Tobita, Yoshiharu
no journal, ,
no abstracts in English
Ito, Keisuke; Ishikawa, Takashi; Naito, Hiroyuki; Ito, Chikara
no journal, ,
no abstracts in English
Sawada, Akihiko; Amaya, Masaki
no journal, ,
no abstracts in English
Chikazawa, Yoshitaka; Kato, Atsushi; Yamamoto, Tomohiko; Iwasaki, Mikinori*; Hara, Hiroyuki*; Shimakawa, Yoshio*; Sakaba, Hiroshi*
no journal, ,
JSFR has double wall sodium boundary to mitigate influence of sodium leak. In this studyk, efficiency of measures are evaluated assuming double boundary failure in severe condition.
Zaima, Naoki; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Nakashima, Shinichi; Yoshida, Hideaki; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Takase, Misao; Haruyama, Mitsuo
no journal, ,
We have just started to develop the uranium mass assay system for 200-litter wastes drums applied active neutron measurements by Non-Destructive Assay (NDA) method composed of the neutron generator used small ultra accelerator and neutron detectors. This system is the extension of the passive neutron system which we had been developed previously, is to be expected to purchase the uranium determination for the actual uranium wastes and to prepare fine data of safe guards. The configurations are that (d,T) accelerator, Helium-3 proportional counters, and 50 cm of concrete structure as reflector and shielding. The uranium mass are determined by counting secondary neutrons generated from nuclear fissions induced from 14 MeV accelerator neutrons. Several mockup wastes drums used the uranium sources had been carried out and reached a conviction of the availability of this methodology.