This paper describes the development of a non-destructive method for analysis of pure-beta minus radioactive sources. An experimental set-up based on plastic scintillation detection system was built for this purpose. It was tested using standard 90Sr/90Y radioactive sources. The experimental results were compared to theoretical calculations based on Fermi’s beta decay theory as well as with Monte-Carlo simulations using a predefined GEANT4 code named rdecay01. All the obtained results showed to be in good agreement.