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Takebe, Shinichi; Sugaya, Toshikatsu; Sasaki, Toshihisa
no journal, ,
no abstracts in English
Ando, Koji; Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Matsushima, Akira
no journal, ,
no abstracts in English
Nishihara, Kenji; Iwamoto, Hiroki; Suyama, Kenya
no journal, ,
no abstracts in English
Kureta, Masatoshi; Soyama, Kazuhiko; Nakamura, Hironobu; Seya, Michio; Ozu, Akira; Nakamura, Tatsuya; Haruyama, Mitsuo
no journal, ,
Alternative techniques to neutron detection by He-3 for safeguards and nuclear security systems are necessary to be developed since He-3 gas shortage is serious. With support of Japanese government (MEXT), we have conducted an R&D project of ZnS ceramic scintillator neutron detectors for non-destructive assay (NDA) of Pu in Fresh MOX fuel and other types of nuclear materials for a use of safeguards verification. Here we present the fundamental tests and the current status of the development of the Pu-NDA system for the demonstration.
Segawa, Mariko; Oi, Motoki; Kai, Tetsuya; Shinohara, Takenao; Kureta, Masatoshi; Sato, Hirotaka*
no journal, ,
no abstracts in English
Yamashita, Susumu; Yoshida, Hiroyuki; Takase, Kazuyuki
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, the numerical results on the melting behavior of the simulated fuel assemblies and reactor structures are reported for several different initial conditions.
Ozu, Akira; Nakamura, Tatsuya; Takase, Misao; Kurata, Noritaka; Haruyama, Mitsuo; Soyama, Kazuhiko; Kureta, Masatoshi; Seya, Michio
no journal, ,
no abstracts in English
Suzuki, Takayuki; Yoshida, Hiroyuki; Nagase, Fumihisa; Abe, Yutaka*; Kaneko, Akiko*
no journal, ,
no abstracts in English
Saito, Ryusuke*; Abe, Yutaka*; Kaneko, Akiko*; Suzuki, Takayuki; Yoshida, Hiroyuki; Nagase, Fumihisa
no journal, ,
no abstracts in English
Kadowaki, Haruhiko; Matsuo, Hidehiko; Yamane, Naoki; Asakura, Yamato*; Matsushima, Akira
no journal, ,
no abstracts in English
Yoshida, Hiroyuki; Nagatake, Taku; Takase, Kazuyuki; Kaneko, Akiko*; Monji, Hideaki*; Abe, Yutaka*
no journal, ,
no abstracts in English
Iwamoto, Osamu
no journal, ,
Covariance data have been evaluated for nuclear data of Pb isotopes in JENDL-4.0. The evaluation has been done for the cross sections such as total, inelastic-scattering, and (n,2n) reactions for the Pb isotopes of 
Pb, 
Pb, 
Pb and 
Pb in continuum energy region using CCONE-KALMAN code system. Model parameter covariance were deduced from uncertainties of cross sections estimated from experimental data using sensitivities of the parameters for optical model, level density and 
-ray strength functions, etc. Cross correlations between reactions were also deduced from the unique parameter covariance for each isotope. Covariance of Legendre coefficients for elastic scattering angular distribution was evaluated. The evaluation methods and results are presented.
Liu, W.; Nagatake, Taku; Takase, Kazuyuki; Yoshida, Hiroyuki; Nagase, Fumihisa
no journal, ,
Severe accidents occurred in the reactors and spent fuel pools of the Fukushima No.1 nuclear power plant after the East Japan Earthquake and the large tsunami occurred on Mar.11, 2011. To cool down the reactors, seawater was injected into the cores. So far, core cooling with seawater has never been assumed and the effect of seawater on heat transfer in reactor core is not clear. To contribute to the understanding of the situations of the reactor cores, Japan Atomic Energy Agency has started the experimental research on the effect of seawater on thermal-hydraulic behaviors including heat transfer. Multiple experiments are to be performed in order to understand the phenomena of the thermal-hydraulic behaviors including the effect of salt precipitation, identify controlling factors, etc. This paper reports a summary of research plan and experimental apparatus to be manufactured.
Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki
no journal, ,
no abstracts in English
Ose, Yasuo*; Suzuki, Takayuki; Misawa, Takeharu; Yoshida, Hiroyuki; Takase, Kazuyuki
no journal, ,
no abstracts in English
Nagatake, Taku; Takase, Kazuyuki; Furuya, Masahiro*; Yoshida, Hiroyuki; Nagase, Fumihisa
no journal, ,
no abstracts in English
Horiguchi, Naoki*; Abe, Yutaka*; Yoshida, Hiroyuki; Kaneko, Akiko*; Uesawa, Shinichiro*
no journal, ,
no abstracts in English
Takamine, Jun; Kureta, Masatoshi; Harada, Hideo; Kitatani, Fumito; Koizumi, Mitsuo; Tsuchiya, Harufumi; Iimura, Hideki
no journal, ,
In the process of dismantlement and reclamation of Fukushima Daiichi Nuclear Power Plant, accounting for and control of nuclear material (NM) in the melted fuel (MF) may be demanded. In Japan Atomic Energy Agency (JAEA), The Neutron Resonance Densitometry (NRD) is proposed. In this method, continuous-energy neutrons are transmitted through NM in MF. And quantity of NM in MF is fixed using neutron resonance absorption peaks derived from measurement results. The prototype system using a compacted D-T fusion pulsed neutron source will be produced in next fiscal year. For getting enough Fixed-quantity precision using this system, it is important to decide arrangement, materials and shapes as high intensity and time resolution as we can. About several kinds of moderator system assumed to be suited for the system, Neutron spectrums and time dependent characteristics were evaluated using MCNP5. Knowledge about the configuration parameters derived from these results will be showed.
Okano, Yasushi; Doda, Norihiro; Ohshima, Hiroyuki; Okubo, Tsutomu
no journal, ,
no abstracts in English
Ebine, Masumi; Birumachi, Atsushi; Nakamura, Tatsuya; Ozu, Akira; Takase, Misao; To, Kentaro; Sakasai, Kaoru; Soyama, Kazuhiko; Kureta, Masatoshi; Seya, Michio
no journal, ,
no abstracts in English