G.M. Brahmanandhan

Seasonal Variation of Indoor Gamma Dose and Radon, Thoron Measurement in the Dwellings around Kudankulam Nuclear Power Plant (Radhapuram Taluk, Tirunelveli District)

Indoor gamma dose and indoor radon, thoron and their progeny concentrations have been measured around the upcoming Kudankulam Nuclear Power Plant i.e., in the Radhapuram taluk. The measurements have been carried throughout a year to account for the seasonal variation of indoor gamma dose and indoor radon, thoron, and their progeny concentrations. Indoor gamma dose value is found to be maximum in the summer season (459.2 ± 82.3 nGy·h-1). Indoor radon, thoron and their progeny concentration are found to be maximum in the winter season. The annual effective dose due to indoor gamma radiation to the Radhapuram population is found to be 1.5 mSv. The total annual inhalation dose arising due to radon, thoron, and their progeny concentrations to population is found to be 1.03mSv in Radhapuram taluk.

Thermoluminescence and photoluminescence studies on gamma irradiated CsI: Pb2+ crystals

Pure and Pb2+-doped CsI crystals have been grown by the Bridgemann technique. Optical absorption, thermoluminescence (TL) and photoluminescence (PL) measurements have been performed. In undoped and Pb2+-doped cesium iodide crystals, F-centers and V-centers have been produced at 770 nm and 350 nm, respectively. In Pb2+-doped crystals, additional centers at 373 nm, 290 nm and 258 nm bands have been produced. In undoped samples, only two glow peaks at 343 K and 373 K have been produced, and in Pb2+-doped samples additional glow peaks at 383 K and 423 K have been produced. For all the samples, TL emission, PL and excitation measurements have been performed.

Background Radiation Dose to the Population Around the Kudankulam Nuclear Power Plant

In Kudankulam (a small village near Cape Comerin, the southernmost tip of the Indian subcontinent), two nuclear power reactors of 1000 MWe each are now under construction. To create baseline data regarding natural background radiation, systematic measurements of the radiation levels in soil, sand, air, and indoors have been performed. Five taluks situated in three different districts lying within a 30-km radius have been chosen as the study area for the present measurements. Primordial radionuclide concentration in sand and soil samples has been measured, and sparse distribution of monazite has been discovered in some places along the coastal areas of Kanyakumari district. The annual effective dose from the three primordial radionuclides in soil samples to the population living around the Kudankulam nuclear power plant is 0.149 mSv/year. The average annual effective dose from primordial radionuclides in sand samples is found to be 0.994 mSv/year. The annual effective dose from indoor gamma radiation has been calculated as 1.18 mSv/year. The effective dose rate from radon, thoron, and their progeny varied from 0.05 to 22.23 mSv/year, with a geometric mean value of 0.62 mSv/year. The overall dissolved radon concentration in drinking water samples was found to vary between background level (<26 mBq/l) and 9939 ± 247 mBq/l.