The goal of this research is the development of a reactive ultrafiltration membrane scintillator for rapid activity determination and isotopic quantification of waterborne special nuclear materials (SNM) to allow for fast forensics analysis of debris from a nuclear event. ZnS:Ag is the best scintillator for the detection of alpha particles that compose the decay of SNM. ZnS:Ag was prepared by the solid state and hydrothermal reaction methods, and characterized on their structure, morphology, luminescence, and scintillation by XRD, Raman scattering, SEM, TEM, photoluminescence, and radioluminescence under X-ray excitation, respectively. For both synthesis methods, luminescence output was maximized at ~0.1-0.2mol% doping. Overall, crystallite size and dominant luminescence emission could be tuned by the synthesis conditions, namely reaction temperature, time, and pH. Co-doping with Al showed significant enhancement of luminescence and scintillation output. Preliminary tests with ZnS:Ag loaded membranes were executed. This work was supported by DTRA under contract HDTRA 1-16-1-0016.