Deformation and rupture characteristics of Indian PHWR fuel pin under loss-of-coolant accident (LOCA)conditions were investigated to develop rupture database that will be used for the formulation andverification of mathematical modeling. Experiments were carried out on single fuel pins over a widerange of initial internal pressures (3–73.5 bar) and in the heating rate range of 7–12 °C/s under inertgas environment. The cladding surface temperature and internal pressure data were recorded on-lineduring the experiment and the cladding deformation and rupture measurements were made on the fuelpins after the test. Rupture characteristics were studied with the help of macroscopic examination ofthe rupture location. It was found that the phase transformation from α to α + β and α + β to β has agreat influence on the material ductility. Two circumferential strain maxima and a minimum at the bursttemperatures of ∼790°C and ∼1030°C and ∼880°C respectively were observed. The burst data of this experiment have been utilized to develop the burst correlation for Zircaloy-4 cladding of PHWR fuelpins.