Simulation study on induced radioactivity in HIAF's cooling water and its disposal and safety implications for...

The induced radioactivity of cooling water is a critical component of accelerator radiation protection. The High-Intensity heavy-ion Accelerator Facility (HIAF), characterized by high particle energy and large beam current, generates strong induced radioactivity in its cooling water, which may pose radiation hazards to personnel and the environment. Therefore, it is necessary to investigate the induced radioactivity of HIAF's cooling water. In this work, a systematic simulation study was performed using the Monte Carlo package FLUKA, combined with the beam loss parameters and the cooling water system design. First, the results indicate that the main radioactive nuclides produced in the cooling water are ¹⁵O, ³H, ¹¹C, ⁷Be and ¹³N. Second, after 30 years of continuous operation, the radionuclide activity concentration in the cooling water of HIAF's six water stations ranges from 3.29 Bq/g to 9.33× 10² Bq/g, and total activity spans from 5.76× 10⁷ Bq to 1.73× 10¹⁰ Bq. In addition, considering the nuclides with γ and β⁺ radiation, the dose rates around the cooling water pipes of each water station were simulated. At a distance of 30 cm from the pipes, dose rates range from 0.17 μSv/h to 21.67 μSv/h. These rates can be significantly reduced by a 1 cm thick lead shield or 1 h of decay. Finally, the decay tanks were designed to ensure that the radioactive wastewater containing ³H and ⁷Be could be safely discharged in accordance with relevant standard. This research provides essential data for the radiation safety management of HIAF and serves as a reference for the related studies on similar accelerator facilities.