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Advisor(s)
Abstract(s)
The natural radioactivity of coal and by-products from coal-fired power plants has been reported in
many countries. Most of these studies focus on the radioactivity levels of airborne discharges with
enhanced concentration in fly ashes. However, the distribution of natural radionuclides in the
environment is crucial to estimate the radiological impact and the resulting risk to the potential
exposed nearby population. The activity released into the atmosphere from of a coal-fired power plants
depends on many factors: the radionuclides concentration in coal, the ash content and inert matter of
the coal, the combustion’s temperature, the portioning between bottom and fly ash and the efficiency
of the filtering system. Therefore, marked differences should be expected between the by-products
produced and the amount of activity discharged, per unit of energy produced, from different coal-fired
power plants (Dinis et al., 2014). At national level, data from coal-fired power plants is not available
as radionuclides measurements are not compulsory; regulations are only restricted to airborne
discharges of SO2, NOx and suspended particles. The consequent radiological impact is rather difficult
to estimate as there is no data concerning the radiological elements released.
This study aims to evaluate the influence of a coal-fired power plant operation on the environmental
radioactivity and the assessment of the resulting radiation hazard through the radium equivalent index
(Raeq). The spatial distribution of the radionuclides found in the surroundings of a coal plant, and the
hazard index, were investigated by statistic and geostatistics tools. The current study was applied to a
coal plant located in the southwest coastline of Portugal. This power plant started working in 1985
with two operational stacks, both with 225 m height, and fuelled by bituminous coal. The main
concern from this coal power plant results mainly from past atmospheric emissions. In fact, the
amount of particulate matter released from this coal-fired power plant into the atmosphere decreased
substantially in the last ten years: 1 740 tons (2001); 812 tons (2004); 587 tons (2007); 394 (2009);
130 tons (2010); 99.7 tons (2010); 286 (2011); 178 ton (2012) (E-PRTR, 2014).