Measurement of Iodine-125 radioactive solid waste derived from sources production laboratory for brachytherapy

Abstract

Purpose: This study aims to present a solid waste management plan for the laboratory of radioactive sources production (LPFR), iodine-125 brachytherapy seeds, located at the Energy and Nuclear Research Institute (IPEN). After the implementation, it is expected to meet a demand of 8000 seeds per month. Methods: Waste from the production of Iodine-125 sources is classified as “Very Low Level Waste Disposal” (T1/2 ≤ 100 days) in the IAEA regulations. Despite that, they have levels of activity above the limits established in standard (CNEN 8.01) needing adequate management in order to guarantee the safety of the installation, operators and environment. The solid waste is generated in Glove box 1, were the fixation reaction (iodine-125 – core) takes place. The wastes from this production are absorbent papers and filters used in surface and air decontamination processes; glass vials, syringes and needles, used in the fixation reaction. Measures of mass, volume and values of activities generated over 5 years of production were performed for each glove box by estimating different scenarios throughout production (supplier switching, variation in activity by radioactive source, etc.). The concentration of activity was also determined in order to meet the criteria established in the standard for safe release of the waste. Results: The final volumes and activities calculated indicated that the laboratory has enough space for temporary storage until the release to the environment (thus not requiring treatment, transport, and another place for management). The data collected proved that a secure management system for radioactive waste within the facility is possible. Conclusion: The management proposed by this work was able to safely contemplate all stages of waste management. This data is indispensable for the construction and licensing of the laboratory.