Environmental Radiological Monitoring Around Kalpakkam

At Kalpakkam, two units of Pressurized Heavy Water Reactors (PHWRs) with the installed capacity of 235 MWe each are operating since 1985. Apart from these reactors, other nuclear facilities such as FBTR, KARP, CWMF and WIP are also situated at Kalpakkam. Due to operation and maintenance of PHWRs and other facilities, continuous low level liquid and gaseous wastes are generated and released into the environment after treatment and dilution. To assess the radiation dose received by the members of the public, if any, due to low level radioactive release, three environmental pathways through which radioactivity can reach man, were considered. During operational period for the last 25 years, regular environmental radioactivity measurement of reactor released radionuclides such as Cs -137, Sr-90 and H-3 was carried out up to 30 km radius from MAPS site. Site specific meteorological data were also collected. From the results, it is revealed that the Cs -137 and Sr-90 activity levels found in the environmental samples around Kalpakkam are comparable to th e global fallout activity levels. Hence dose due to Cs -137 and Sr-90 is negligible and not related to MAPS release. Only the mean internal dose due to tritium and computed external dose due to FPNG and Ar-41 were calculated and it was found that the mean annual dose received by a hypothetical man staying at 1.6 km fence post is always less than 2 to 3% of the AERB dose limit (1 mSv/year) of which Ar-41 contributes 97 to 98%. At farther distances the radiation dose received are of low order and hence insignificant.