DEVELOPMENT OF HIGH-FRAME-RATE NEUTRON RADIOGRAPHY AND QUANTITATIVE MEASUREMENT METHOD FOR MULTIPHASE FLOW RESEARCH

In relation to the establishment of thermal neutron radiography as a m easurement method with high accuracy and reliability, this paper revie wed the present status on the development of high-frame-rate neutron r adiography with a steady thermal neutron beam and its application to m ultiphase flow researches. This review included also the present progr ess on the quantification of neutron radiographic image at Kyoto Unive rsity, i.e. (1) quantitative method to measure void fraction of two-ph ase flow with thermal neutron radiography (Sigma-scaling method), (2) influence of scattered neutrons on void fraction measured by neutron r adiography, (3) measurement error of neutrons in a low neutron flux fi eld, (4) error in void fraction measurement due to low gray level, and (5) measurement error due to low imaging speed Moreover, a new experi mental approach on a total macroscopic cross section for thermal neutr ons measurement by neutron radiography was presented. This paper revea led neutron radiography to be a promising visualization and measuremen t method in thermal hydraulic research. (C) 1998 Elsevier Science S.A. All rights reserved.