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Fate modelling of artificial radionuclides (ARs) in top soils are necessary to assess the radiological effects to population. Among ARs, 137Cs, 90Sr and 131I are very important since the large abundances in the environment. In this study, the fates of 137Cs, 90Sr and 131I in the surface soil layers were simulated by the soil model which was developed by the Canadian Centre for Environmental Modelling and Chemistry (CEMC). The scenario that 137Cs, 90Sr and 131I contaminated in topsoil in the exclusion of Fukushima Daiichi nuclear power plant (NPP) accident was evaluated. The results show the expected time for the minimum hazardous level of exposure. It is 115.5 days after the exposure, when the total effective dose is 1 mSv y−1 in which 0.46 mSv y−1 from ingestion and 0.54 mSv y−1 from gamma exposure. Hazard levels due to exposure progresses are varied in order gamma exposure (82.14%) > ingestion (17.47%) > inhalation (0.39%). The hazard levels from radionuclides are varied in order 137Cs (63.34%) > 131I (33.48%) > 90Sr (3.18%).

The experimental characterization of an aged PIPS detector used in an alpha-particle spectrometry is performed using a standard mixed source of 238 U, 234 U, 239 Pu, and 241 Am. The variations in the detector efficiency and resolution (FWHM) at the main energy lines of the 238 U, 234 U, 239 Pu and 241 Am source were investigated at all possible source–detector distances under chamber air pressure of ∼ 1.33 Pa. Finding shows that on average, the counting efficiency data obtained from measurements are lower than those obtained by theoretical data and Monte Carlo simulation (SOLANG and AASI) methods. A combination of polymeric strippable coating and both traditional wiping and cleaning method for the detector decontamination works only show a significant reduction in the background activity. The counting efficiency improvement process by an increase of the higher voltages within the recommended range results in a good agreement in the counting efficiency comparison and a slight decrease of the detector dead layer thickness. Novel method to evaluate the dead layer thickness for PIPS detector via the variations in experimental energy loss with respect source to detector distance using alpha standard sources of 242 Pu has been proposed. This method can help to predict a default dead layer thickness value which will be as close as it was originally, is less than 50 nm from the manufacturer.

Twelve types of chemical fertilizers commonly used in the south of Vietnam were collected for analysis. It was found that the activity concentration of 226Ra was in the range from below detectable level (BDL) to 139 Bq kg−1 while gross alpha and gross beta activities were in the ranges from BDL—691 Bq kg−1 and BDL—18753 Bq kg−1 respectively. The correlation was found between gross alpha activity and activity concentration of 226Ra in most of fertilizers. The radiological hazard due to application of fertilizers is insignificantly under the agricultural conditions.

In this study, radioactivity of airborne particulate and rainwater samples were analysed during 2016 at three different sites in Ho Chi Minh City, Vietnam. The activities of gross alpha and gross beta measured in airborne particulate are in the range from (

Fate modelling of artificial radionuclides (ARs) in top soils are necessary to assess the radiological effects to population. Among ARs