Heavy fuel oil and ash samples were collected from
the Assiut thermal power plant in Egypt and subjected to
gamma spectrometry analysis for natural radioactivity
contents. Considerable results were observed where the ash
contains nearly 1,000 times natural radionuclides more than
raw oil. The results were confirmed by measuring the samples
via using different devices in different institutions. All ash
samples had radium equivalent activities and external hazard
index values more than 370 Bq/kg and unity respectively. The
mean absorbed dose rate was10,650 nGy/h which is nearly
190 times higher than the global average value of 55 nGy/h.
The corresponding annual external effective dose is estimated
to be 13 mSv/year, which is nearly 30 times higher than that in
areas of natural background radiation (0.46 mSv/year).