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Oikawa, Kenichi; Sato, Hirotaka*; Watanabe, Kenichi*; Su, Y. H.; Shinohara, Takenao; Kai, Tetsuya; Kiyanagi, Yoshiaki*; Hasemi, Hiroyuki
Journal of Physics; Conference Series, 2605, p.012013_1 - 012013_6, 2023/10
Tsuchikawa, Yusuke; Kai, Tetsuya; Abe, Yuta; Oikawa, Kenichi; Parker, J. D.*; Shinohara, Takenao; Sato, Ikken
Journal of Physics; Conference Series, 2605, p.012022_1 - 012022_6, 2023/10
We developed a method to obtain the areal density distribution of boron, which has a large neutron cross section, by means of an energy resolved neutron imaging. Commonly in a measurement of elements with very high neutron sensitivity, the quantitative measurement becomes more difficult with the amount of element due to the neutron self-shielding effect. To avoid this effect, an energy-resolved method using known cross section data was attempted, and a quantitative imaging of such elements was demonstrated at the MLF of J-PARC. This presentation introduces a measurement of melted simulated-fuel assemblies obtained in the research of the Fukushima Daiichi Nuclear Power Plant after the severe accident. Energy-dependent neutron transmission rates of the samples were measured by a neutron imaging detector, and were analyzed to obtained the areal density of boron at each position.
Kurita, Keisuke; Iikura, Hiroshi; Tsuchikawa, Yusuke; Kai, Tetsuya; Shinohara, Takenao; Odaira, Naoya*; Ito, Daisuke*; Saito, Yasushi*; Matsubayashi, Masahito
Journal of Physics; Conference Series, 2605, p.012005_1 - 012005_6, 2023/10
The Japan Research Ractor-3 (JRR-3) is operation resumed on February 26, 2021, and the shared use was also restarted in July, 2021. With the resumption of JRR-3 operation, two imaging facilities called TNRF and CNRF have also resumed their utilization. In this presentation, we report the details of these two neutron facilities.
Ito, Daisuke*; Odaira, Naoya*; Ito, Kei*; Saito, Yasushi*; Kurita, Keisuke; Iikura, Hiroshi
Journal of Physics; Conference Series, 2605, p.012024_1 - 012024_6, 2023/10
Gas-liquid two-phase flow appears in many heat-exchanging devices. To understand the phenomena in such devices, the two-phase flow dynamics should be clarified. In this study, high-speed neutron imaging is applied to the measurements of two-phase flow dynamics, and the accuracy of the void fraction measurement is investigated.
Saito, Yasushi*; Ito, Daisuke*; Odaira, Naoya*; Kurita, Keisuke; Iikura, Hiroshi
Journal of Physics; Conference Series, 2605, p.012028_1 - 012028_6, 2023/10
To observe flow velocity distributions by Neutron Imaging, suitable tracer is necessary. The requirements are its density, its visibility, and its wettability (if applied to liquid metal). Gold cadmium tracers have been developed for the Pb-Bi two-phase flow, however, the visibility have not been verified depending on the particle size and the measurement system. As the candidates of tracer particles, Ag, Cd, Au-Cd, and Ag-Cd have been tested by varying its compositions and its diameters. Results show enough visibility if the particles size is larger than 1mm. In addition, Cd tracer particles were applied to the fluidized bed, where the bed materials are metallic particle made of stainless steel, with 1mm diameter. The diameter of Cd trace is about 1.5 mm. From the neutron imaging, the visibility of the tracers is enough to measure the velocity distributions in the fluidized bed.
Shinohara, Takenao; Kai, Tetsuya; Oikawa, Kenichi; Su, Y. H.; Tsuchikawa, Yusuke; Hayashida, Hirotoshi*; Parker, J. D.*; Matsumoto, Yoshihiro*; Kiyanagi, Yoshiaki*
no journal, ,
Su, Y. H.; Parker, J. D.*; Shinohara, Takenao; Oikawa, Kenichi; Kai, Tetsuya; Gong, W.; Harjo, S.; Kawasaki, Takuro; Aizawa, Kazuya; Kiyanagi, Yoshiaki*
no journal, ,
Kurita, Keisuke; Saito, Yasushi*; Ito, Daisuke*; Odaira, Naoya*; Iikura, Hiroshi
no journal, ,
Experiments have been performed to estimate the rising velocity of gas bubbles or water droplets in a liquid-metal pool. Dynamic behaviour of two-phase bubble evaporating in a molten alloy was clearly observed by using high-frame rate neutron imaging at 500 fps. Measurements of drag coefficient have been made for a single nitrogen gas bubble and for a water droplet including two-phase bubble evaporating in the liquid metal. The relationship between the rising velocity of a single bubble/droplet in the molten Newton's alloy was clarified in detail taking the bubble/droplet shape.
