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Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Kado, Kazumi
JAEA-Technology 2013-050, 39 Pages, 2014/03
A uranium mass assay system NWAS, for 200-litter wastes drums applied by NDA method was developed and accumulated the data of the actual uranium bearing wastes drums. The system consists of the 16 pieces of Helium-3 proportional counters for neutron detection generated from U-234(,n) reaction or U-238 spontaneous fissions with polyethylene moderation and a Germanium solid state detector for ray detection as to determine uranium enrichment. The satisfactory works had been continued and the uranium determination data of 850 drums had been accumulated approximately. On the other hand several considerable problems on the system or methodology had been revealed technically or analytically through the measurements experiences. Furthermore as the next improvement plans, the active neutrons assay for uranium bearing wastes drums are now progressing. The results of complications will lead us to the progressive next steps.
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.
Nakatsuka, Yoshiaki; Zaima, Naoki; 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.
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.
Zaima, Naoki; Tokizawa, Takayuki; Nakatsuka, Yoshiaki; Nakashima, Shinichi; Yoshida, Hideaki; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao; Haruyama, Mitsuo; Takase, Misao; et al.
no journal, ,
no abstracts in English
Nakatsuka, Yoshiaki; Zaima, Naoki; Nakashima, Shinichi; Fujiki, Naoki*; Ozu, Akira; Haruyama, Mitsuo; Kureta, Masatoshi
no journal, ,
no abstracts in English
Suwaki, Takuro*; Zaima, Naoki; Nakashima, Shinichi; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Kureta, Masatoshi; Ozu, Akira
no journal, ,
Japan Atomic Energy(JAEA) configurated the non-destructive assay (NDA) systems, which applied to the bulk state nuclear inventory and actual uranium bearing waste drums generated from Ningyo-Toge uranium plants. The methodology of newly active neutron assay systems (JAWAS-N) is based on the fast neutron direct interrogation (FNDI) method developed by NSEC. The systems are composed of neutron generator and He-3 proportional counters with concrete structures functioned as reflector or shielding. FNDI method is defined as followings. Neutron generator produces pulses of 14 MeV neutrons that are directed into drum to induce U-235 fissions in matrix. Secondary fission neutrons generated from U-235 with fast or epithermal neutron energy will be detected by He-3 proportional counters with the diffusion decay time on the order of hundreds micro-second. Neutron detectors which are designed to detect only fast and epithermal neutrons, will be extracted fission neutrons by mathematical analysis methods and be determined U-235 mass. The Systems will be contributed to the field of material accountancy in Ningyo-Toge uranium plants. The systems' verifications through the mockup tests and trials for actual waste drams measurement will be reported.
Nakatsuka, Yoshiaki; Zaima, Naoki; Nakashima, Shinichi; Fujiki, Naoki*; Suwaki, Takuro*; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao
no journal, ,
The historical procedures and target of active neutron measurements devices will be reported beside requirements of SG/MA tools. Also introduced the principles of FNDI methods and its applicability.
Fujiki, Naoki*; Nakatsuka, Yoshiaki; Zaima, Naoki; Nakashima, Shinichi; Suwaki, Takuro*; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao
no journal, ,
The performances of methodological characteristics, operation stability and radiation control of active neutron measurements devices will be reported.
Suwaki, Takuro*; Zaima, Naoki; Nakatsuka, Yoshiaki; Fujiki, Naoki*; Nakashima, Shinichi; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao
no journal, ,
The mockup tests used standard uranium source and simulated matrices have been successfully performed. The well performances of this device are introduced.
Zaima, Naoki; Nakatsuka, Yoshiaki; Nakashima, Shinichi; Fujiki, Naoki*; Suwaki, Takuro*; Kureta, Masatoshi; Ozu, Akira; Komeda, Masao
no journal, ,
The trials for measuring actual waste drums have been performed, and validated good applicability active neutron measurements device on site.