Development of a Neutron Radiography Three-Dimensional Computed Tomography System for Void Fraction Measurement of Boiling Flow in Tight Lattice Rod Bundles

A neutron radiography three-dimensional computed tomography (NR3DCT) system was developed to visualize the void fraction distribution of boiling flow in tight lattice heated-rod bundles. This paper chiefly reports on the data processing and the error estimation method of NR3DCT. Practical γ-ray noise reduction and image correction techniques were studied to improve the reliability of the experimental data. Using the system and a directly heated 14-rod bundle test section, the behavior of boiling flow in a tight lattice rod bundle was clearly visualized. The effect of each data processing step on the result was also discussed. By this development, the three-dimensional vapor distribution of boiling flow in a heated bundle is made clear, and void fraction databases can be provided for verification of a thermal-hydraulic simulation code.

[1]  B. F. Logan,et al.  The Fourier reconstruction of a head section , 1974 .

[2]  T. Hibiki,et al.  Influence of scattered neutrons on void fraction measurement of two-phase flow using thermal neutron radioscopy , 1997 .

[3]  N. Takenaka,et al.  Three-dimensional visualization of void fraction distribution in steady two-phase flow by thermal neutron radiography , 1998 .

[4]  Koji Yoshii,et al.  Application of fast neutron radiography to three-dimensional visualization of steady two-phase flow in a rod bundle , 1999 .

[5]  Kazuyuki Takase,et al.  Development of Predictable Technology for Thermal/Hydraulic Performance of Reduced-Moderation Water Reactors (3) : Current Status of Development of Three-Dimensional Two-Phase Flow Simulation Method , 2003 .

[6]  N. Kardjilov,et al.  Energy-selective neutron radiography and tomography at FRM. , 2004, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[7]  E. Lehmann,et al.  Comparison of X-ray and neutron tomography investigations of geological materials , 2005, IEEE Transactions on Nuclear Science.

[8]  U. Bonse,et al.  First phase-contrast tomography with thermal neutrons , 2005, IEEE Transactions on Nuclear Science.

[9]  Masahito Matsubayashi.  Study on development of advanced neutron radiography imaging techniques , 2005 .

[10]  M. Dierick.  Tomographic Imaging Techniques using Cold and Thermal Neutron Beams , 2005 .

[11]  T. Nakanishi.  Detection of wood discoloration in a canker fungus-inoculated Japanese cedar by neutron radiography , 2005 .

[12]  Takamichi Iwamura,et al.  Conceptual Design of Innovative Water Reactor for Flexible Fuel Cycle (FLWR) and its Recycle Characteristics , 2007 .