Speaker
Description
This study assesses the radiological risks of using fly ash from major Vietnamese coal-fired power plants as a supplementary building material. Using HPGe gamma-ray spectrometry, the activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were quantified to calculate internationally recognized hazard indices and model indoor radon exposure scenarios. Results revealed significantly elevated ²²⁶Ra and ²³²Th levels. Notably, four of six samples exceeded the Activity Concentration Index regulatory limit of unity (TCXDVN 397:2007), and two samples exceeded the internal hazard index limit. The maximum calculated annual effective dose reached 1.545 mSv/year, surpassing the ICRP's 1 mSv/year public limit, with a corresponding Excess Lifetime Cancer Risk up to 5.20 × 10⁻³. These findings demonstrate substantial radiological heterogeneity among sources and underscore the critical need for mandatory screening and a risk-based classification framework in Vietnam.
Keywords: Fly Ash; NORM; Radiological Hazard; Radon; Building Materials; Vietnam; Gamma Spectrometry; TCXDVN 397:2007