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Komeda, Masao; Maeda, Makoto; Furutaka, Kazuyoshi; Tobita, Hiroshi; Hattori, Kentaro; Shimofusa, Taichi; Ozu, Akira; Kureta, Masatoshi
Proceedings of INMM 57th Annual Meeting (Internet), 10 Pages, 2016/07
We are working on the development of a non-destructive assay (NDA) measurement system using the Fast Neutron Direct Interrogation (FNDI) method. The FNDI method is a kind of active neutron technique and can measure the total amounts of fissile materials (U-235, Pu-239, Pu-241). We have already carried out design analyses of an NDA measurement system for measuring the debris assuming use of the Three Mile Island (TMI) canister model. The result was presented at the Institute of Nuclear Materials Management (INMM) 56th Annual Meeting. Since then, we have modified the design of the NDA measurement system for the fuel debris and canister models at 1F. In this paper, we provide the calculation and evaluation results using the modified NDA measurement system. Moreover, we provide analytical investigations of the influence of fuel debris including high fissile material content on measurements.
Komeda, Masao; Maeda, Makoto; Shimofusa, Taichi; Tobita, Hiroshi; Ozu, Akira; Kureta, Masatoshi
no journal, ,
He-3 detectors are most popular for NDA systems of the active neutron method. However, the price of He-3 detectors is rising due to short supply of the He-3 gas, and it is concerned that the cost of fabricating a NDA system with many He-3 detectors is rising. A new hybrid detector called B-10 plus detector has been developed by GE Reuter-Stokes. The B-10 plus detector has higher detection efficiency than a B-10 detector while the usage of He-3 gas is reduced. We make a report on experimental results of performance comparison between He-3 detectors and B-10 plus detectors on the active neutron method.
Komeda, Masao; Maeda, Makoto; Furutaka, Kazuyoshi; Tobita, Hiroshi; Hattori, Kentaro; Shimofusa, Taichi; Ozu, Akira; Kureta, Masatoshi
no journal, ,
This report describes applicability evaluation results of active neutron technique (AN) for characterization study of candidate technologies for nuclear material quantification in fuel debris at Fukushima Daiichi Nuclear Power Station. In this characterization study, we used the Fast Neutron Direct Interrogation (FNDI) method which is one of the active neutron methods. We had performed simulation studies of the FNDI measurement system for measuring the debris using the Three Mile Island (TMI) canister model. Since then, we have modified the design of the FNDI measurement system in order to apply the new canister model, and carried out simulations of a common set of debris models. As the result of the simulations, it has been found that the fissile mass can be measured with an error of less than 20% under the condition in which B-10 density is less than 0.04 wt%.