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Sowmya M.,Anna University | Senthilkumar B.,Anna University | Seshan B.R.R.,Anna University | Hariharan G.,Anna University | And 3 more authors.
Radiation Protection Dosimetry | Year: 2010

The activity concentration of naturally occurring radioactive elements such as 226Ra, 232Th and 40K were measured for 46 soil samples collected in the vicinity of the Madras atomic power station, Kalpakkam, South India using gamma-ray spectroscopy. The average activity concentration of 226Ra, 232Th and 40K in soil samples were found to be 22.6±12.6, 92.8±44.3 and 434.1±131.1 Bq kg-1, respectively. The activity concentration of natural radionuclides is higher than the world average except for 226Ra. The external absorbed gamma dose rates due to 226Ra, 232Th and 40K are observed to be 74.6±30.8 nGy h-1 with a corresponding annual effective dose of 91.5±37.8 μSv y-1, which are also above the world average. The values of radium equivalent activity and external hazard index are less than the world average. Whereas, the values of the radioactivity level index (Iγ) and the total gamma dose rate were found to be above the required criterion. © The Author 2010. Published by Oxford University Press. All rights reserved. Source

Shrivastava R.,Bhabha Atomic Research Center | Dash S.K.,Indian Institute of Technology Delhi | Oza R.B.,Bhabha Atomic Research Center | Hegde M.N.,Environmental Survey Laboratory
Annals of Nuclear Energy | Year: 2015

In this study, the Weather Research and Forecasting (WRF) model performance with various combinations of parameterization schemes is analyzed in predicting surface and upper air meteorology around the Kaiga nuclear power plant site. The case studies selected for simulation correspond to occurrences of annual maximum, minimum temperature and maximum wind speed in the years (2004-2007). Based on the collective performance of the various combinations of the schemes in reproducing observed winds, temperature and relative humidity at Kaiga site, the most suitable combination of parameterization schemes are identified. For temperature and relative humidity, the combination consisting of Asymmetric Convective Model (ACM2) as the Planetary Boundary Layer (PBL) scheme, the Monin Obhukhov as the surface layer (SL) scheme and the 5 layer thermal diffusion model as the land surface model (LSM) is found to be better than other combinations whereas the combination consisting of Mellor Yamada Janjic (Eta) as the PBL scheme, Monin Obhukhov Janjic (Eta) as the SL scheme and Noah LSM performs reasonably well in reproducing the observed wind conditions. This indicates that the selection of parameterization schemes may depend on the intended application of the model for a given site. © 2014 Elsevier Ltd. All rights reserved. Source

Ross E.M.,Scott Christian College Autonomous | Raj Y.L.,Scott Christian College Autonomous | Wesley S.G.,Scott Christian College Autonomous | Rajan M.P.,Environmental Survey Laboratory
Journal of Environmental Radioactivity | Year: 2013

The activity concentrations of certain radionuclides were quantified in some plant foods cultivated around Kudankulam, where a mega-nuclear power plant is being established. The activity concentrations were found more in the 'pulses' group and were the lowest in 'other vegetable' category. The annual effective dose was computed based on the activity concentration of radionuclides and it was found to be higher due to the consumption of cereals and pulses. Other vegetables, cereals, pulses and nuts recorded high transfer factors for the radionuclide 228Ra. Fruits, leafy vegetables, tubers and roots, and palm embryo registered high transfer factors for 226Ra. Group-wise activity concentration, radiation dose to the public and soil-plant-to-transfer factor are discussed in detail. © 2012 Elsevier Ltd. Source

Rao D.D.,Bhabha Atomic Research Center | Sudheendran V.,Environmental Survey Laboratory | Sarkar P.K.,Bhabha Atomic Research Center
Applied Radiation and Isotopes | Year: 2012

Determination of actinides in environmental and biological samples is an important activity of radiation protection program at nuclear energy facilities. High resolution alpha spectrometry with passivated ion implanted Silicon detectors is widely used for the determination of actinides concentration. Low levels of activity concentrations in these samples often require long counting duration of a few days to obtain accurate and statistically significant data for further impact assessment. In alpha spectrometry, the chamber in which Si detector operated is a critical component and maintained at a desired vacuum for minimizing the alpha particle attenuation. Experimental evaluation of variations in energy resolution and tailing of alpha spectra was investigated under different chamber air pressures from about 6.7. Pa to more than 2700. Pa under the chamber hold mode and pump electrically switched off conditions. As part of validation, data collected on an IAEA inter-comparison exercise sample are presented under short and long counting durations with pump operating and switched off conditions respectively. It has been observed that the FWHM values do not significantly degrade, to impact the low and medium level concentration alpha spectra, for variations in vacuum chamber pressures from about 6.7. Pa to 2700. Pa. © 2012 Elsevier Ltd. Source

Shrivastava R.,Bhabha Atomic Research Center | Dash S.K.,Indian Institute of Technology Delhi | Hegde M.N.,Environmental Survey Laboratory | Pradeepkumar K.S.,Bhabha Atomic Research Center | Sharma D.N.,Bhabha Atomic Research Center
Journal of Environmental Radioactivity | Year: 2014

The TRMM rainfall product 3B42 is compared with rain gauge observations for Kaiga, India on monthly and seasonal time scales. This comparison is carried out for the years 2004-2007 spanning four monsoon seasons. A good correlation is obtained between the two data sets however; magnitude wise, the cumulative precipitation of the satellite product on monthly and seasonal time scales is deficient by almost 33-40% as compared to the rain gauge data. The satellite product is also compared with APHRODITE's Monsoon Asia data set on the same time scales. This comparison indicates a much better agreement since both these data sets represent an average precipitation over the same area. The scavenging coefficients for 131I and 137Cs are estimated using TRMM 3B42, rain gauge and APHRODITE data. The values obtained using TRMM 3B42 rainfall data compare very well with those obtained using rain gauge and APHRODITE data. © 2014 Elsevier Ltd. Source

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