An Application test for active neutron technology "FNDI" on uranium wastes drums, 1; Formation of active neutron NDA instruments

Nakatsuka, Yoshiaki; Zaima, Naoki; Fujiki, Naoki*; Nakashima, Shinichi ; Yoshida, Hideaki; Kureta, Masatoshi   ; Ozu, Akira  ; Komeda, Masao   ; Takase, Misao; Haruyama, Mitsuo

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.