Finnis-Sinclair potential for Zr developed by Mendelev and Ackland (2007). Surprisingly, currently used interatomic potentials do not encapsulate the unique properties of Zr, namely its high stacking-fault energy, anomolous self-diffusion, melting and phase transformation under temperature and pressure (or alloying). Ab initio calculations have shown deficiencies in the description of point defects, both vacancies and interstitials, using existing interatomic potentials, deficiencies that can now be rectified by refitting. Here, we show the calculation of phase transitions self-consistently and present a potential for Zr that correctly reproduces the energetics of our extended database of ab initio configurations and high-temperature phase transitions. The potential has an analytic many-body form, making it suitable for existing large-scale MD codes. We also present a best-fit potential for the hcp structure and its defects. of the potential, according to the developer Graeme Ackland (as reported in the NIST IPRP), close-range repulsion has been added for radiation studies.v3_10_hcp (in C:\SIMULATION.MD\Zr\Results\v3_10)"potential is in fact the deprecated potential).