A decade (2011-2020) of environmental monitoring of tritium and its committed effective dose assessment around Rawatbhata Rajasthan site

Monitoring of anthropogenic tritium levels in the environment of Rawatbhata Rajasthan Site is carried out by Environmental Survey Laboratory up to 30 km radial distance to ensure that discharges and effective dose to public are within permissible limits due to operation of five pressurized heavy water reactors 220 MWe capacity. Released tritium from five operating NPP units (mostly in the form of HTO) are discharged to the atmospheric environment through 100m tall stacks and to aquatic environment to fresh water lake of Rana Pratap Sagar (RPS) as per technical specifications approved by AERB. In this study tritium concentration in environment (air and surface water) at various radial zones (1.6 km and beyond up to 30 km) and associated internal dose to representative person is presented for the period 2011-2020 during different seasons. Air sampling was carried out by moisture condensation method. 10 mL of collected air moisture and water samples are mixed with 10mL of DIN based counting cocktail in 20mL plastic vail and counted for 100min. In ultra-low-level liquid scintillation analyser (Perkin Elmer make). Minimum detectable level achieved is 0.1 Bq/m³ and 5 Bq/L in air and water samples respectively. Maximum CED due to inhalation and ingestion of tritium at 1.6 km during the study period is 2.3 μSv with median value of 1.1 μSv which is much less than dose limit of 1mSv to representative person at this site