Tritium surface loading due to contamination of rainwater from atmospheric release at NAPS (2011)

Annual tritium (HTO) surface loading 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 eight locations in different directions. The technique for measured values consists of the summation of product of tritium concentration (Bq/l) in daily rainfall samples and daily rainfall (mm). Tritium surface loading studies at NAPS reveal that a fraction 1.01E-03 of total annual tritium released through stack gets deposited on the surface due to washout/rainout of plume within 0.8 km radial distance from stack. The range of deposition velocity, Vw (m.s-1) i.e., the ratio of annual tritium surface loading W (Bq. m-2.s-1) and annual mean tritium concentration in air, c0(Bq.m-3) at three locations for the years 2011 is found to be 6.12E-04 to 2.89E-03. The average value for wet deposition velocity Vw for NAPS site is estimated as 3.17E-03 m.s-1. (author)