Serbian thermal power plants (TPPs) produce siliceous fly ash from lignite in
the quantity of approximately 6 million tons per year. The potential market
for the use of fly ash is operational, but for the time being, only used by
cement producers. Fly ash radioactivity could be one of the major points of
concern when larger use of fly ash is planned, particularly in the Serbian
construction industry. Radioactivity measurements have been conducted
regularly for decades. This paper presents the results of a ten-year fly ash
radioactivity measurements at the Nikola Tesla B TPP located in Obrenovac. In
addition, the paper compares the natural radionuclides coal content data
combusted by the Nikola Tesla B TPP boilers coming from the Kolubara Basin
and ash created during coal combustion. Fly ash created in the Nikola Tesla
TPPs boilers is characterised by the increased concentration of the natural
radionuclides content compared to coal. This is the so-called technologically
enhanced natural radioactivity (Technologically Enhanced Occurring
Radioactive Material - TENORM) of industrial waste, whereas the average
specific activities: 232Th in coal amount to 25.2 Bq/kg, and in fly ash and
coal 84.2 Bq/kg and 238U 38.3 Bq/kg, respectively. Following the obtained
natural radionuclides content results it may be concluded that the Nikola
Tesla B TPP ash may be disposed into the environment. Ash may be used also in
the construction industry (civil engineering). In building construction
applications, ash share as the additive to other building materials depends
from its physical and chemical characteristics, as well as from the
radionuclides activity: 266Ra, 232Th and 40K. Unlike the thermal power plants
regularly (once a year) testing the specific natural radionuclides activity
in the combusted coal and boiler fly ash, Electric Power Industry of Serbia
has not performed large-scale investigations of the natural radionuclides
content in coal within the Kolubara Mining Basin. Natural radionuclides
content in fly ash is compared to the combusted coal some 3 - 4 times higher
and may present a limitation for applying ash in the construction industry.
In view of the above, and considering the construction industry interests in
using the Nikola Tesla B TPP ash, regular investigations of the natural
radionuclides content in ash created in the thermal power plants should be
carried out, together with the Kolubara Mining Basin coal combusted by the
Nikola Tesla B TPP and other PE EPS thermal power plants. The current
Kolubara Mining Basin coal characteristics investigation programme should be
supplemented by the natural radionuclides content of the uranium (238U,
226Ra) and thorium series (232Th) and potassium 40 (40K).
Study of Natural Radioactivity, Radon Exhalation Rate and Radiation Doses in Coal and Flyash Samples from Thermal Power Plants, India
