Project 8 Development on Neutron Imaging Application (R2P8)

概要

1. Objectives and Allotted Research Subjects: Neu- tron imaging provides valuable information which cannot be obtained from an optical or X-ray imaging. The pur- pose of this project is to develop the imaging method itself and also the experimental environment for expand- ing the application area of the neutron imaging. The al- lotted research subjects are as follows:

ARS-1: Measurements of Multiphase Dynamics by Neutron Radiography (Y. Saito et al.)
ARS-2: Void Fraction Measurement of Refrigerant Two-Phase Flows in Cross-Flow Parallel Mini-Channel Evaporator (H. Asano et al.)
ARS-3: Visualization of Transient Change of Re- frigerant Distribution in Activated Carbon Parti- cle Layer (H. Asano et al.)
ARS-4: Neutron radiography measurements of the mixing behavior of reactant streams during hy- drothermal synthesis (S. Takami et al.)
ARS-5: Quantatively Visualization of a Microchan- nel Heat Exchanger under Non-uniformly Heated Condition (H. Umekawa et al.)
ARS-6: Frost Deposition Distribution Estimated by X-ray and Neutron Cooperative Imaging (R. Matsumoto et al.)
ARS-7: 3D Imaging of Plant roots (U. Matsushima et al.)
ARS-8: Analysis of vapor pressure in fire spalling of high-strength concrete (M. Kanematsu et al.)
ARS-9: Measurement of coolant inside a flat lami- nate vapor chamber in the vertical posture with Neutron Radiography (K. Mizuta et al.)
ARS-10: Visualization of Organic Materials for De- velopment of Industrial Applications (M. Kitaguchi et al.)
ARS-11: Visualization of Excimer cluster tracers by using Neutrons (Y. Tsuji et al.)
ARS-12: Development of Neutron Imaging Tech- niques and Its Application (T. Sakai et al.)
ARS-13: Dynamic Visualization of Hydrogen Accu- mulation Behavior in Metallic Materials via Neu- tron Imaging (K. Shimizu et al.)
ARS-14: In-situ Lithium diffusion behavior in NA- SICON-Type Structured Lithium Ion Conductive Composite by Means of Neutron Radiography (S. Takai et al.)

2. Main results and the contents of this report: To develop neutron imaging, our imaging system was de- veloped so that high-speed imaging could be per-formed at thermal neutron flux of 107 n/cm2s. Such improved system was shared with all of the project members and valuable results were obtained as follows:

ARS-1 improved the above-mentioned high-speed im- aging system at the B4 port. The spatial and temporal resolution of the system was tested. Then, the present system was applied to investigate the effect of motion blur in the observation of rapidly moving object and to visualize particle motions dropped in a molten glass.
ARS-2 applied to neutron imaging to refrigerant two-phase flows in a cross-flow parallel mini-channel evaporator. HFC-134a and FC3283 were used as the re- frigerant. From the measurement results, the effect of rib in the mini-channel was clarified in the two-dimensional void fraction distributions. It indicates that the offset rib is not effective.
ARS-3 applied neutron imaging to measurements of re- frigerant distribution in activated carbon, which is strongly related to the performance of adsorption refrig- erator. Liquid ethanol was used as the refrigerant. Tran- sient change of the refrigerant in the activated carbon particle layer.
ARS-4 applied neutron imaging to the flow visualization of mixing behavior of reactant streams during hydro- thermal synthesis. Water and Aqueous solution of GD(CH3C)3 was fed into T-junction tube using high pressure pumps, simultaneously. Due to the attenuation of neutron in Gd in the aqueous solutions, the mixing be- havior was clearly visualized.
ARS-5 applied the neutron imaging to boiling two-phase flow in a microchannel heat exchanger under non-uniformly heated conditions. The effect of heat flux distributions on the heat transfer was estimated.
ARS-6 applied neutron imaging to frosting behavior in cooling heat exchange system. Simultaneous Xray and neutron imaging was performed to clarify the 3D frost deposition at the B4 port.
ARS-8 applied neutron imaging to analysis of vapor pressure in fire spalling of high-strength concrete. Meas- uring moisture transfer inside concrete quantitatively, how vapor pressure inside concrete affect spalling was considered.
ARS-9 applied neutron imaging to measurements of coolant distribution in a flat laminate vapor chamber. Experiments were performed at the E2 port. Measure- ment results indicate that the liquid thickness depends mainly on the inner structure of the vapor chamber rather than its outer size and shape.
ARS-13 performed dynamic visualization of hydrogen accumulation behavior in metallic materials. However, the contrast of image was not enough. Probably the absolute value of the hydrostatic stress was relatively low, or the size of the formed hydrostatic stress field was much smaller that the spatial resolution of the de- tector system.
ARS-14 applied to in-situ Lithium diffusion behavior in NASICON-Type structured Lithium Ion conductive composite. From measurement results, it indicates that the material should be changed.

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