Diurnal variation of meteorological parameters and assessments of dilution characteristics of atmospheric releases at Rawatbhata Rajasthan site during 2018–2022

This study aims to investigate the diurnal and seasonal variation of surface meteorological parameters. Atmospheric dispersion patterns for unit release rate at Rawatbhata Rajasthan site (RR site) have been also studied using collected meteorological data at 10 m and 100 m heights during 2018–2022. Predominant wind direction for RR site is South-West (8.03%), and predominant wind speed class for 10 m and 100 m heights is 6–11 kmh − 1 (39.51%) and 12–19 kmh − 1 (33.18%), respectively. A 5-year hourly average maximum temperature of 40.5°C was observed in the month of May at 15:00 h and a minimum temperature of 10.7°C at 07:00 h in the month of January. The maximum diurnal variation of hourly average temperature is observed in the month of March (14.5°C) and minimum in the month of July (5.0°C). The annual average value of atmospheric pressure during 2018–2022 is 965.5 m bar at this site. Stability category F is most dominant at this site due to a high percentage of light wind speed class 6–11 kmh − 1 (39.51%) at 10 m height. Stability category F is highest (>45%) during the months of October to March. During the south-west monsoon period from July to September, neutral category D is predominant. The monthly dilution factor indicates that atmospheric releases spread toward the North-East sectors, during June to August. In September to November months, atmospheric spread shifts toward the South-East direction. In the summer months, the spread is in maximum sectors due to higher fluctuation in wind direction. The knowledge of site-specific meteorological parameters and dilution characteristics will aid in providing effective support for risk management and to assess radiological impact during normal and emergency conditions at nuclear facilities.