IMPROVED TECHNIQUE FOR HYDROGEN CONCENTRATION MEASUREMENT IN FUEL CLADDINGS BY BACKSCATTERED ELECTRON IMAGE ANALYSIS (II)

摘要

The measurement technique for hydrogen concentration using Backscattered Electron Image (BEI) analysis (BEI method) had been developed by Studsvik Nuclear AB. The hydride in claddings is identified using BEIs with Scanning Electron Microscope and the hydrogen concentration is calculated from the area fractions of the hydride in those BEIs. The BEI method is suitable for the measurement of local hydrogen concentration in fuel claddings.rnIn the Reactor Fuel Examination Facility, the sample polishing techniques and image processing procedure for BEI method were improved to measure the hydrogen concentration in the irradiated fuel claddings more precisely. In the previous confirmation tests using the un-irradiated fuel claddings, which were reported in the last seminar, the hydrogen concentrations measured by the improved BEI method gave good agreement with the results of Hot Vacuum Extraction method (HVE).rnThe radial and axial hydrogen concentration profiles of the irradiated fuel claddings were measured with improved BEI method. As the results of these measurements, the local hydrogen concentration could be indicated more precisely with the improved BEI method compared to the other methods for the hydrogen concentration measurement and observation.