Speaker
Description
A comprehensive radiological baseline is essential for strengthening national preparedness against potential transboundary nuclear incidents. This study establishes a high-resolution environmental radiation database for Hanoi, Vietnam. Radiation indicators—including ambient gamma dose rates in the air and the activity concentrations of primordial radionuclides ($^{238}\text{U}$, $^{232}\text{Th}$, and $^{40}\text{K}$) in soil and sediment—were systematically measured. The survey methodology, employing in-situ gamma dosimetry and laboratory-based high-purity germanium (HPGe) gamma spectrometry, adhered to both national and international standards.The mean gamma dose rate in the air for Hanoi was determined to be $0.068\text{ µSv/h}$. This value is consistent with both the national average for Vietnam and the global average reported by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). The mean activity concentration for $^{238}\text{U}$ was $40.83\text{ Bq/kg}$ in Hanoi, while for $^{232}\text{Th}$, the concentration was $60.92\text{ Bq/kg}$. Notably, $^{40}\text{K}$ showed elevated levels at $583.61\text{ Bq/kg}$.The results indicate that regional radiation levels fall within the normal range of the natural background, with spatial distributions influenced by underlying geology and anthropogenic activities, particularly the elevated $^{40}\text{K}$ concentrations in agricultural areas. This dataset provides a critical and definitive baseline for distinguishing natural radiation variations from potential future radiological contamination, thereby enhancing Vietnam's nuclear emergency preparedness capabilities.
Keywords: Gamma dose rate, $^{238}\text{U}$, $^{232}\text{Th}$, $^{40}\text{K}$, Environmental radioactivity, Emergency preparedness, Hanoi.