Abstract: Background: The sample preparation system of 14C is necessary for measuring the radioactive contents of 14C and 3H for the decommissioning of nuclear reactor. Previous works were concentrated on the glass container and heating furnace which is not suitable for automatic sample process and exists safety risk. Purpose: In order to resolve the difficulty in main materials of nuclear reactor samples preparation of 14C, an intellectual preparation system of 14C samples was designed and developed. Methods: The system is designed to consist of buffer, decomposition chamber, catalysis bed, adsorption bed and absorbing bed. Samples were decomposed at high temperature in oxygen whilst the generated gas was translated to CO2 by catalysis oxidation. The activity of 14C was measured by liquid scintillation counter using suspension method. Results: The radiochemical recovery rate of 14C was above 70%. The calculated detection limit for 14C was 0.033 1 Bq?g?1 for graphite and 0.021 8 Bq?g?1 for concrete, respectively. Conclusion: This system was stable enough to be used for preparing graphite and concrete samples which contain low level or medium level radioactivity in nuclear reactor.

Key words: 14C, Intellectualization, Graphite, Concrete, Reactor body material