Understanding of host-to-impurity energy transfer process is crucial for the development of efficient and fast response scintillator materials. In this work, Pr3+ doped Na3LuSi3O9 (NLS) double salt silicate has been successfully synthesized using a high temperature solid-state reaction method and further comprehensively characterized by means of XRD measurements, crystal structure refinement, luminescence spectroscopic and time-domain study upon VUV-UV and X-ray synchrotron excitation, and thermally stimulated luminescence (TSL) study. Based on these results a model of host to Pr3+ 4f15d1 and 4f2 has been proposed. It has been demonstrated that NLS:Pr3+ has a good potential for fast response scintillator applications due to the presence of an efficient energy transfer from host electronic excitations to Pr3+ 4f15d1 states. The Pr3+ 4f15d1→4f2 emission reveals a good thermal stability and is characterized by a lifetime of about 16 ns. Upon pulse X-ray excitation the main fast decay component is accompanied by slower one with lifetime of about 64 ns that is ascribed to the presence of shallow traps which retrap carriers and cause appearance of delayed recombination. Parameters for the corresponding traps have been calculated based on the TSL glow curve analysis.