Project 1 Development of Neutron Imaging Application

Neutron imaging provides valuable information which cannot be obtained from an optical or X-ray imaging.The purpose of this project is to develop the imaging method itself and the experimental environment for expanding the application area of neutron imaging.The allotted research subjects are as follows:-1: Measurements of Boiling Two-Phase Flow Dynamics in a Heated Tube (D. Ito et al.) ARS-2: Void Fraction of Silicon-oil Flow with Microbubbles in Horizontal Tube (H.Asano et al.) ARS-3: Adaptation of Neutron Radiography for the Evaluation of Two-phase Flow (H.Umekawa et al.) ARS-4: Observation of Condensation on a Single Flat Tube (R. Matsumoto et al.) ARS-5: An integrated neutron radiography-based observation of spalling behavior in concrete containing ground granulated blast furnace slag (M.Kanematsu et al.) ARS-6: Visualization of the Reactant Solution Distribution in a Mixer of a Super-critical Hydrothermal Flow-Type Reactor Using Gd3+ Ion Solution as a Tracer (S.Takami et al.) ARS-7: Visualization of Root Water Uptake in Organic Substrates through Three-Dimensional Root Reconstruction from Cylindrical Panoramic Imaging (U.Matsushima et al.) ARS-8: In-situ Observation of Lithium Migration in Solid Electrolyte by Using Neutron Radiography (S.Takai et al.) ARS-9: Measurement of coolant distribution in a flat laminate vapor chamber utilizing neutron radiograpy (K.Mizuta et al.) (not performed) MAIN RESULTS AND THE CONTENTS OF THIS REPORT:ARS-1 performed visualization of boiling two-phase flow by high-speed imaging.A stainless-steel tube with an inner diameter of 7mm was electrically heated and the boiling two-phase flow was observed in the tube by high-speed neutron imaging at 1,000 fps.ARS-2 applied to neutron imaging to void fraction measurements of silicone oil/gas two-phase flow to investigate the effect of void distribution on the heat transfer characteristics.From measurement results, at flow rate of 1.0 l/min, the bubbles appeared to flow more in the upper region due to buoyancy, but at 2.0 l/min, they were observed to be homogeneously dispersed.ARS-4 evaluates the condensation on a single flat tube.In this experiment, dropwise condensation was observed by neutron imaging, and as the droplets grew and coalesced, increasing in size, their downward motion due to gravity was observed.ARS-5 investigates the integrated neutron radiography-based observation of spalling behavior in concrete containing ground granulated blast furnace slag.ARS-6 visualized the reactant solution distribution in a mixer of a supercritical hydrothermal flow-type reactor using Gd 3+ Ion solution as a tracer.ARS-7 combined a three-dimensional (3D) root surface model reconstructed from cylindrical panoramic photographs with neutron D₂O absorption images, enabling non-destructive correlation of root position with water uptake in organic substrates.ARS-8 applied the electric field to the model cell to observe the lithium migration in the solid electrolyte through neutron imaging.ARS-9 intended to investigate the coolant distributions in a flat vapor chamber by using neutron radiography, however, the experiments were not performed in this year.