Formation of hydride in zircaloy-4 cladding tube

In order to study the effect of hydride formation on zirconium alloys, a reliable hydrogen charging method is required. A modification of an electrochemical method developed by previous authors is described. In this high temperature cathodic hydrogen charging method, the alloy specimen is the working electrode. The modification lies in the technique for the determination of the hydrogen content of the alloy. Results are presented for the hydrogen pick-up of a specimen of zircaloy-4 tubing which is used as cladding for nuclear fuel rods. The hydriding of the alloy is shown in optical micrographs and the presence of zirconium hydrides demonstrated in x-ray diffraction spectra. (3 figures; 3 tables; 7 references) (UK)