Cs-137 activity in fly ash from thermal electric power stations

Abstract

Radioactive '^’Cs has a great concern because of its long half-life (30.2 year) and its similarity to potassium which is an essential element for humans. It is well known that Cs is distributed in surface soils or specifically adsorbed on illicit clay minerals and finally enters to organisms. '"Cs is made through nuclear accidents and processes is an example of anthropogenic radionuclides. In the present work, '”Cs specific activity concentration is measured with a high efficiency gamma ray spectroscopy NaI(TI) detector in fly ash samples from two thermal electric power stations in the south of Iraq (Al-Naserya and Al-Musaeb). The '"’Cs specific activity concentration are founded with ranges from 20d4.8 Bq kg-1 to 120z27.6 Bq kg ' at Al-Naserya and 17+4.4 Bq kg ' to 86zl9.8 Bq kg 1 at Al-Musaeb station. Some of these values are alerted us to take care about the received dose because these concentrations are higher than background and world-wide limit (37 Bq kg ' From UNSCEAR). Also, the presented '"’Cs specific activity concentration results point out an additional shot to the measured effective dose rate, which can be predicted to be the 1"’Cs and cosmic radiation. By accounting for the contribution of 13’Cs in the estimated absorbed dose rate, applying the conversion coefficient 0.136 (nGy h ' per Bq kg '). If a human inhale the air every day for 70 years, the radiation dose must be less than the dose limit (1 msv y '). In case "’CS is present, the criterion is the activity of ’”Cs /60 - 1.