Evaluation of tritium dispersion in the atmosphere by Risψ Mesoscale Puff modeling systems using on-site meteorological parameters for the nuclear site Tarapur, India

Abstract

Dispersion models are important predictive tools that are used to simulate the way the atmosphere transports and diffuses contaminants from industrial sources of pollution. Risψ Mesoscale Puff (RIMPUFF) modeling system is used to simulate the radioactive H-3 released into the atmosphere through stack height of 100 m from a Tarapur Atomic Power Station 3 and 4 (TAPS 3 and 4) to predict downwind tritium ambient air concentrations in the environment around nuclear power plants. The tritium air concentrations by field measurement (measured tritium air concentrations using bubbler setup in the areas adjacent to TAPS 3 and 4, a pressurized heavy water reactor [PHWR]) were compared with that by calculation to validate the modeling system RIMPUFF for the Tarapur site. The computed and measured atmospheric tritium concentrations were quite consistent in trend and magnitude and the value of fractional bias computed is − 0.2524 (i.e., model predictions are within a factor of 2). This RIMPUFF modeling system will be useful in reviewing and evaluating environmental radiological impacts for PHWRs, especially it will be of great help to predict the behavior of tritium in the atmospheric environment around nuclear power plants during emergencies. Tritium concentrations in ambient air computed and measured at various locations around TAPS 3 and 4 showed a best fit regression line passing through the origin as Y (computed concentration) = 0.6725 X (measured concentration) with correlation coefficient of 0.75.