Studies on the Rain Scavenging Process of Tritium in a Tropical Site at Narora in India

Abstract

This study presents the results of systematic experiments on tritium (3H) concentrations in ground level air against those in rainwater near a pressurized heavy water reactor in a tropical region. The samples were collected over the rainy season of year 2011 from eight locations in the environment around Narora Atomic Power Station. The specific activity ratio of 3H between rainwater and air moisture at ground level was calculated for each data set. The average specific activity ratio was found to be ranged from 0.12 to 1.1. A correlation ( to 0.76, ) was observed between the total rain hours in a day and the rainwater 3H activity. Higher rain duration with slower rain rate yielded higher 3H concentrations as more time was available for the scavenging/wash-out process to take effect together with lower dilution. Annual tritium (HTO) wet deposition has been measured and calculated for the year 2011 within 0.8 km distance from 145 m high stack of Narora Atomic Power Station (NAPS) at nine locations in different directions. The range of deposition velocity, (m·s−1), at nine locations for the years 2011 is found to be from 4.43E − 04 to 6.42E − 03. The average value for wet deposition velocity for NAPS site is estimated as 3.17E − 03 m·s−1.