ENVIRONMENTAL IMPACT ASSESSMENT OF COAL FIRED POWER PLANTS AND NUCLEAR POWER PLANTS IN INDIA

摘要

Coal plays an increasingly important role in meeting the energy needs of India. One of the environmental problems associated with the use of coal as a fuel for Indian thermal power plants is the generation of very large amounts of fly ash. Coal contains trace quantities of the naturally occurring primordial radionuclides and so coal burning is one of the sources of technologically enhanced exposure of man from natural radionuclides. The concentrations of these radionuclides are usually very low. However, when coal is burnt in thermal power plants the fly ash emitted through the stack becomes enriched in some radionuclides; hence, combustion of coal on a large scale for thermal power generation has an important impact on the environment. Coal combustion accounted for about 65% of the installed capacity for power generation in 1994. Many of the thermal power plants in India are situated in densely populated areas. The major coal fields in India are situated in the densely populated eastern parts of the country. The natural radioactivity content in samples from these coal fields is found to be higher than that from other coal fields. The Bhabha Atomic Research Centre has carried out extensive studies of coal and fly ash samples collected from more than 30 thermal power plants with an installed capacity of 10 000 MW(e), spread all over the country, to determine their natural radioactivity content. The radiation doses to the population residing within a radius of 88.5 km (50 miles) from such plants have also been computed. The collective effective dose commitments from these plants are 206 man·Sv/a for bones, lungs and thyroid and 73 man·Sv/a for the whole body. The dose commitments to the population living within a radius of 88.5 km from coal fired plants and nuclear power plants in India have also been computed and the estimated doses from these two types of energy production have been compared.