Study on concrete activation characteristics and safety management strategies for 30 MeV medical cyclotrons

This study systematically analyses the concrete activation problem and associated radiation risk caused by long-term operation of medical cyclotron. The research shows that medium energy (10-30 MeV) medical cyclotrons under high current operating conditions can induce concrete activation with penetration depths of 100-120 cm, mainly producing long-lived radionuclides such as Eu-152 and Co-60 with activity concentrations up to 600 Bq g^-1and 250 Bq g^-1, respectively. Under operation at maximum design parameters, the peak ambient dose equivalent rate around the target chamber reaches 961μSv h^-1at the end of operation and remains above 500μSv h^-1even after two years of cooling, posing significant radiation risks to personnel. China's current radiation safety management system faces the twin challenges of a lack of standards and insufficient radioactive waste management capacity. Based on international practices such as IAEA, recommendations are proposed to improve the management system in three dimensions: revision of regulations and standards, financial safeguards, and technological innovation.