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Tsuchiya, Harufumi; Toh, Yosuke; Ozu, Akira; Furutaka, Kazuyoshi; Kitatani, Fumito; Maeda, Makoto; Komeda, Masao
Journal of Nuclear Science and Technology, 60(11), p.1301 - 1312, 2023/11
Times Cited Count：3 Percentile：65.16(Nuclear Science & Technology)Yasue, Ayumu*; Kawakami, Mayu*; Kobayashi, Kensuke*; Kim, J.*; Miyazu, Yuji*; Nishio, Yuhei*; Mukai, Tomohisa*; Morooka, Satoshi; Kanematsu, Manabu*
Quantum Beam Science (Internet), 7(2), p.15_1 - 15_14, 2023/05
Komeda, Masao; Ozu, Akira; Mori, Takamasa; Nakatsuka, Yoshiaki; Maeda, Makoto; Kureta, Masatoshi; Toh, Yosuke
Journal of Nuclear Science and Technology, 54(11), p.1233 - 1239, 2017/11
Times Cited Count：9 Percentile：60.81(Nuclear Science & Technology)The previous active neutron method cannot remove the influence of the multiplication effect of neutrons produced by second- and subsequent fission reactions, and it might overestimate the amount of nuclear material if an item contains large amounts. In this paper, we discussed the correction method for the neutron multiplication effect on the measured data in the fast neutron direct interrogation (FNDI) method, one of the active neutron methods, supposing that the neutron multiplication effect is caused mainly by third-generation neutrons from the second-fission reactions under the condition that the forth-generation neutrons are much fewer. This paper proposed a correction method for the neutron multiplication effect in the measured data. Moreover we have shown a possibility that this correction method gives rough estimates of the effective neutron multiplication factor and the subcriticality.
Rodriguez, D.
no journal, ,
With the improvement of technology, safeguards verifications must consider how to declare precise uncertainties, especially for new non-destructive assay techniques. For our delayed 
-ray spectroscopy technique, we are utilizing the inverse Monte Carlo analysis method. Systematic uncertainties are determined by analyzing full Monte Carlo spectra using the same analysis applied to the data. Preliminary results will be presented at this workshop.
Tsuchiya, Harufumi; Harada, Hideo; Koizumi, Mitsuo; Kitatani, Fumito; Kureta, Masatoshi; Takamine, Jun; Iimura, Hideki; Kimura, Atsushi; Becker, B.*; Heyse, J.*; et al.
no journal, ,
Neutron Resonance Densitometry (NRD) is a non-destructive method using a pulsed neutron beam in order to quantify nuclear materials in particle-like debris of melted fuel that is generated by a severe accident like the one at the Fukushima Daiichi Nuclear Power Plant. It is a combination of neutron resonance transmission analysis (NRTA) and neutron resonance captures analysis (NRCA) or Prompt Gamma-ray Analysis (PGA). NRCA/PGA in NRD, using a newly designed -ray detector, plays a role of measuring impurities in debris that would have high radioactivity derived from 
Cs. Especially, the -ray detector was specially designed to measure 478-keV rays radiated by 
B under the presence of Cs. Then utilizing information on the amount of impurities obtained by NRCA/PGA, NRTA quantifies special nuclear materials in debris. To verify the effectiveness of NRD for quantifying nuclear materials, NRTA and NRCA/PGA experiments were conducted at GELINA, IRMM, by an international collaboration of JAEA and EC/JRC/IRMM. In addition, achievable accuracy concerning NRD was studied by Monte Carlo simulations. In this contribution, these achievements on NRD as well as its concept are reviewed.
