[en] This study investigates the effect of meteorological parameters on Total Suspended Particulate Matter concentration in air at Kalpakkam site during 2017. The observed daily TSPM concentrations varied from 4.2 μg/m³ to 13.6 μg/m³ at Kalpakkam which is very much lower than Central Pollution Control Board (CPCB) permissible limits. The effect of meteorological parameters temperature, unstable stability category and calm conditions showed positive correlation with TSPM, while Solar Irradiance (SI), wind speed and minimum relative humidity showed inverse relation with TSPM. The possible physical processes involved in the direct and inverse relation with TSPM variation with respect to meteorological parameters are discussed. (author)

[en] In coastal regions, sea breeze (SB) is an important factor for atmospheric dispersion of pollutants and influences air temperature, humidity wind speed and direction in the land mass. We identified monthly SB hours for the Kalpakkam site during 2016 and 2017 based on these change in meteorological conditions. From the results it is found that SB conditions occur about 10% in a year and has inverse relation with rainfall. Hence the effects of SB conditions will not significantly affect the annual concentration or dose however, it will have effect on short term dispersion calculations which is normally used for intervention and source term estimation during daytime. The effect of SB conditions on the pollutant requires detailed study using coupled CFD and meso-scale models, which is a future scope. (author)

[en] Tritium in the environment exists as free water tritium (TFWT) and bound tritium (TBT). Tissue bound tritium consists of exchangeable and non-exchangeable forms. The non-exchangeable TBT is referred as Organically Bound Tritium (OBT). The radiological significance of OBT is higher compared to HTO because of its longer residence time. The technique used for extraction total tritium including OBT involves decomposition of the sample and the oxidation of all liberated tritium to HTO which is trappe in a solution kept in bubbler. A commercially available sample oxidiser system was used for the analysis of tritium in samples. This paper gives the details of optimisation of various parameters such as composition of trapping solution, volume of solution, counting time for effective measurement of tritium in environmental samples

[en] The topographic characteristics of a complex terrain site are significantly different from those at flat terrain site due to different type of wind flow conditions. The rough surface retards the wind flow from a smooth surface, which results in sharp decrease in wind speed, change in vertical profile along with atmospheric stability. The estimation of site specific surface topographic parameters such as surface roughness length Z_0 and friction velocity U* which are related to the roughness characteristics of the terrain, require wind speed profile (0-200m height from surface) for the concerned site. In this paper sector dependent Z_0 and U* for Kalpakkam site is evaluated under neutral conditions for the year 2014 using data measured in 50 m height meteorological tower at Kalpakkam. The sector dependent and nature of Z_0 and U* parameters in relation to the site topographic features and its consequence in the atmospheric dispersion models are discussed

[en] Meteorological parameters wind speed, temperature, humidity and stability play a very important role in the transport and dispersion of particulate matter affecting the concentration of Total Suspended Particulate Matter (TSPM). These parameters vary from place to place, month to month and also during day and night. In addition coastal atmospheric conditions widely vary compared to inland site due to land sea interface. This paper presents the results of correlation between various meteorological parameters and TSPM at Kalpakkam (12° 33inch N, 80°11inch E) on the east coast, about 75 km south of Chennai, India

[en] Assessment of radiological impact and for planning and preparedness programs, monthly atmospheric dispersion patterns at Kalpakkam have been studied using observed surface meteorological data during 2015-2020. The influence of meteorological factors such as wind speed, wind directions, percent of calm, atmospheric stability, and rainfall on dispersion patterns has been evaluated. The higher wind speed range (>4 m/s) is observed from 11:00 h to 19:00 h with an average wind speed of 4.17 m/s and the highest value observed in the month of May. Extremely stable F category and percent of calm observed to be lowest in the month of June. This study reveals that the high concentration area is toward seaside sectors during the southwest monsoon season from June to September and the remaining months, January to May and October to December, the most probable dispersion toward southwest, South, and North covering land sectors. Wet deposition due to maximum rainfall and more rainy days in the month of November during the northeast monsoon. The study provides site-specific information on dispersion patterns, an essential tool and crucial support for risk management with respect to radiological impact, monitoring and assessment in normal and emergency scenarios of a nuclear facility, and guiding resources for siting and design of the new facility in and around Kalpakkam. (author)

[en] The accurate knowledge of the surface topographic parameters, which represent terrain characteristics of a site, is required in atmospheric dispersion modeling. The rough surface retards the wind flow from a smooth surface, which results in sharp decrease in wind speed, change in vertical profile along with atmospheric stability. Dispersion models require extrapolation of wind speed U_R_e_f at measured height Z_R_e_f to the wind speed U_S_t_a_c_k at stack height Z_S_t_a_c_k , based on power law wind profile. Wind speed profile can be evaluated using site specific surface scaling parameters roughness length Z_0 and friction velocity U_*. In this paper, sector dependent Z_0 and U_* for Kalpakkam site is evaluated for neutral category and the sector values of Z_0 are explained according to the terrain features. The maximum and minimum Z_0 was observed in SSE (0.84 m) and N (0.26 m) upwind sectors due to the presence of more number of residential buildings, sand dunes and high traffic, in contrast to N sector where mostly agricultural farming lands are present. The site specific wind speed profile index P is calculated based on Z_0 for different sectors leads to better estimation of annual dilution factor and gamma dose on the part of neutral category computation. The surface scaling parameter mean surface drag coefficient C_D was estimated to be 0.16, which implies urban environment at Kalpakkam site. (author)

[en] The field measurements of "3H in the form of HTO present in air moisture carried out around Madras Atomic Power Station were compared with predicted values using atmospheric dispersion modeling. Air "3H samples were collected from different sectors at the site boundary of the operating reactors for the period of 2 y and compared with Gaussian Plume model. The predictions were comparable with the measured value. The slight variation observed between the two methods is attributed to the uncertainty involved in the measurement of air "3H concentration and in the measurement of site-specific meteorological parameters. The radiation dose imparted to members of public due to the levels observed is well within station technical specification limit for "3H. (authors)

[en] This paper presents the analysis of BARC established environmental radiation monitoring network (IERMON) observed values in 7 locations at Kalpakkam and estimated dose with regulatory Gaussian Plume Model (GPM) during 2017. The monthly dose estimated with GPM due to releases from MAPS is highly correlated with IERMON measurements especially within 2km distance and well below the regulatory (AERB) permissible limits. This study confirms that online IERMON data could be used for early warning system of detection, activation of emergency response and inverse calculation of source term during nuclear emergency. (author)

[en] ¹⁴C is produced both naturally and artificially in the Environment. It is one of the potential source of radiation exposure due to its biological importance and long half-life. Measurement of ¹⁴C in biota samples using Pyrolyser was optimised for sample size, duration of oxidisation, volume of trapping solution and counting time. Based on recovery obtained 2 g sample size and set temperature of 600°C were optimised. As part of quality assurance an inter lab comparison of terrestrial samples was carried out. (author)