EVALUATION OF 25 Y OF ENVIRONMENTAL MONITORING DATA AROUND MADRAS ATOMIC POWER STATION (MAPS),KALPAKKAM, INDIA

摘要

The Environmental Survey Laboratory at Kalpakkam, India carries out elaborate monitoring programme involving atmospheric, terrestrial and aquatic samples for radioactivity to evaluate the impact of operating two pressurised heavy water reactors. This paper presents the evaluation of 25 y (1983-2008) data. Statistical analysis of the environmental data for different radionuclides showed that the data best fits log-normal distribution. The data analysed showed that fission products such as ~(137)Cs, ~(90)Sr and ~(131)I were due to global fallout only. A ratio of 0.2 was obtained for ~(90)Sr to ~(137)Cs in air filter samples, only during Chernobyl accident period. The transfer factor of ~(137)Cs and ~(90)Sr for rice was computed to be 0.23 and 0.03 and vegetables 0.25 and 0.10, respectively. Activation products ~3H and ~(41)Ar are the only radionuclides that are related to MAPS operation. A strong correlation (r = 0.9) was observed between ~3H activity in air and ~3H discharged to the atmosphere. A similar correlation (r = 0.8) was observed in ~3H concentration in seawater and ~3H discharged in the liquid waste. The annual internal dose due to ~3H and annual external dose due to ~(41)Ar evaluated in the last 25 y show that the members of the public received less than 2 ％ of the dose limit (1 mSv y~(-1)) set by ICRP 72.