The fast and spontaneous hydrogen diffusion in zirconium alloys used in the nuclear industry leads to the hydride precipitation which is often pointed as causing embrittlement and rupture. Though XRD, TEM and SEM-EBSD analyses we demonstrate that the nature of hydride phases depends the hydrogen content and can show crystallographic orientation relationships (ORs) with the substrate. DSC has been used to identify the dissolution and precipitation energies at global scale. The difference of both can be associated to the misfit dislocations contribution to the precipitation. These results are confirmed at a local scale by in-situ TEM hydride dissolution. The depinning...