Effect of Zirconium Hydrides on the mechanical behavior of cladding

During some operations previous to the dry storage, which involve high temperature and hoop stress on the cladding, a part of the hydride platelets may precipitate along the radial direction. As a consequence, cladding embrittlement may occur. In this paper, the experimental techniques developed for the authors to produce hydride reorientation in unirradiated cladding are shown. Samples of fuel cladding with 150 and 500 ppm of hydrogen were prepared. Subsequently, these samples were subjected to reorientation treatments by applying high temperature (400 degrees C) and constant hoop stress (60, 90, 120 and 140 MPa). Finally, ring compression tests (RCT) were carried out to study the cladding embrittlement. Samples after the reorientation treatment (i.e. with radial hydrides) were subjected to RCT at 20, 135 and 300 degrees C and the results are discussed.