News Excerpt:

Based on an analysis of radiological data of 20 years (2000-2020) from six nuclear power plants based in India, researchers at the Bhabha Atomic Research Centre (BARC), Mumbai have found that the radioactive discharges from the nuclear plants and the resultant potential environmental impact have been “minimal”.

Key findings of the study:

• While samples were collected and measured for a maximum radius of 30 km of each nuclear plant, the study found that the concentrations of fission products beyond 5 km radius was below the minimum detectable activity of the instruments used, implying that the monitored values were “insignificant”. 
• The study focussed only on the concentrations of fission products and neutron-activated nuclides values within 5 km of each nuclear plant.
• As per the study, average gross alpha activity in air particulates at all the seven nuclear plants was less than 0.1 megabecquerel (mBq) per cubic metre.
• The average radionuclides (iodine-131, caesium-137, and strontium-90) in air particulates across all the seven sites and the average iodine-131 activity concentration was below 1 mBq per cubic metre.
• While in the case of caesium-137 and strontium-90, the average concentrations were three orders lower and below 10 microbecquerel per cubic metre.
• In the case of rivers and lakes, the concentration of caesium-137 and strontium-90 were below 5 mBq per litre.
• While the concentration was less than 50 megabecquerel per litre in sea water near the nuclear plants.
• As per researchers, tritium was found “detectable above the minimum detectable activity in all the sites except in the Kudankulam Nuclear Power Station. 
• In the case of the Kudankulam power plant, tritium was “not detected in any single time during the period of study”, while its concentration was “relatively higher” at the Rajasthan Atomic Power Station.
• Though the total doses have been lower than the regulatory limits, the total dose at the Rajasthan atomic power station, Madras atomic station and Tarapur atomic power station have been relatively higher. 
• This is because at both the Rajasthan and Madras power stations, the “air-cooled reactor assemblies result in activation of natural argon to radioactive argon-41” before being released into the environment. 

Radioactive discharges from Indian nuclear plants:

• The gaseous waste that is released to the atmosphere through stacks consists of fission product noble gases, Argon 41, radioiodine, particulate radionuclides - cobalt-60, strontium-90, caesium-137 - and tritium. 
• The liquid discharge consists of fission product radionuclides - radioiodine, tritium, strontium -90, caesium-137 - and activation products like cobalt-60.
• The radioactive discharges are carried out through dilution and dispersion and by “adhering to strict radiological and environmental regulatory regimes”.

Related News: Kudankulam Nuclear Power Plant, Kakrapar Atomic Power Project