Improved technique to measure hydrogen concentration in the cross section of the fuel cladding

Onozawa, Atsushi ; Harada, Akio; Honda, Junichi; Yasuda, Ryo; Nakata, Masahito; Kanazawa, Hiroyuki; Nishino, Yasuharu 

In the Reactor Fuel Examination Facility in JAEA, high temperature extraction method (HTE) has been used for hydrogen analysis in post irradiation examinations. However, it has not been suitable technique to measure radial distribution of hydrogen concentration in the cross section of the fuel cladding. Hydrogen concentration in the cross section of the fuel cladding can be measured with the backscattered electron image (BEI) analysis; In BEI, brightness of zirconium hydride is different from that of matrix. BEI is processed to binary color between zirconium hydride and matrix to evaluate those areas. The area ratio of zirconium hydride to matrix is converted into hydrogen concentration. This reports stated that condition on sample preparation, technique to take BEI, and image processing procedures were improved for BEI method. In addition, the hydrogen concentration of un-irradiated cladding was measured with the improved BEI method to compare to the HTE.