Spalling in tantalum has been observed in an experiment aiming at testing an antiproton production target prototype at CERN’s HiRadMat Facility. The experiment consisted in impacting 47 intense and high-energy proton beams onto a target equipped with ten cylindrical cores made of tantalum of Ø8 mm by 16 mm. Each of these proton beam impacts induced a sudden rise of temperature in the bulk of the Ta cores around 1800 ◦C in 0.9 μs leading to the excitation of a vibration mode which exposed their material to compressive-to-tensile pressures ranging from 2 GPa to 9 GPa, with pressure rates up to 20 GPa/μs. Post-irradiation analyses such as neutron tomography and metallographic examination of the cores, revealed the creation of voids in the bulk of the tantalum cores ranging from to 2 μm to 1 mm in diameter. These voids present a non-uniform size and density distribution within the cores, with limited growth and coalescence in areas subjected to higher temperatures and tensile pressures. Grain-growth due to a fast, thermally-induced, recrystallization has been also observed in some zones. In this work, we present a detailed characterization of the unique thermal and mechanical load that has induced this spall process by means of Finite Element and hydrocode simulations, together with post-experiment microscope and EBSD observations of the Ta rods. This analysis suggests that spall-induced void growth and coalescence is enhanced in the temperature and pressure window of 1300-1800 ◦C and 3-6.5 GPa, whereas is restrained at temperatures and tensile pressures above 2000 ◦C and 6.5 GPa. In addition, the analysis suggests that full thermal-recrystallization in tantalum can take place when exposed to temperatures above 2000 ◦C for less than 2 s. Four different hypotheses to explain the observed void size distribution trends are presented.