Quantification of excess Carbon-14 specific activity in terrestrial biota in the off-site locations of the PHWR nuclear power plant at Kaiga, India.

This is the first detailed study on C activity in the environment surrounding a nuclear facility in India. Samples of food matrices and wild plants from the off-site locations of the PHWR nuclear power plant (NPP) at Kaiga were analysed by liquid scintillation spectrometry, results were validated by accelerator mass spectrometry, and an extensive database (N = 142) was established. The stable isotope ratio of carbon (δC) in terrestrial plants varied from -33.

NE-OBT and TFWT activity concentrations in wild plants in the vicinity of the PHWR nuclear power plant and control regions of the tropical monsoonal climatic region of the Indian subcontinent.

The results of the first detailed study, involving a large number of samples, on water equivalent factor (WEQ), non-exchangeable organically bound tritium (NE-OBT) and tissue free water tritium (TFWT) activity concentrations in predominant plant species of the tropical monsoonal climatic region, are presented. A total of 369 samples from the vicinity of the PHWR nuclear power plant (NPP) at Kaiga, West Coast of India, and 47 samples of the control region (region not affected by local anthropogenic sources) were analysed. The WEQ varied in the range of 0.

Experimental database on water equivalent factor (WEQ) and organically bound tritium activity for tropical monsoonal climate region of South West Coast of India.

Tritium in the form of tritiated water is easily incorporated into terrestrial biota as tissue free water tritium (TFWT). A part of TFWT is converted into organically bound tritium (OBT) through metabolic processes. For the computation of NE-OBT activity (expressed as Bq L of combustion water) in terrestrial plants, knowledge on 'water equivalent factor (WEQ)', defined as the volume of water produced from the combustion of 1 kg of the dry sample, is essential.

Optimisation of a batch thermal combustion method using a tube furnace oxidation system (pyrolyser) and LSC for carbon-14 determination in environmental matrices.

Accelerator mass spectrometry and benzene synthesis coupled with liquid scintillation spectrometry are often used for accurate measurements of C activity in the environmental matrices. Thermal oxidation is one of the methods employed for C determination in environmental matrices. In this method, the sample is oxidised at high temperature (600-900 °C) to convert carbon species to CO and trapped in an amine-based absorber for determining the activity in a liquid scintillation counting (LSC) system.

Determination of Organically Bound Tritium (OBT) Concentration in Fish by Thermal Oxidation and Liquid Scintillation Counting Method.

Effluents containing tritium (H) dispersed into the fresh water or marine environment from nuclear facilities can be taken up by biota. Aquatic and marine organisms are among the important pathways through which tritium can enter into the human body, and hence, assessment of the extent of pollution of these ecosystems is very important for radiation dose assessments. Tritium present in environmental matrices can be classified as tissue-free water tritium (TFWT) and organically bound tritium (OBT).

A WALK-IN TYPE CALIBRATION CHAMBER FACILITY FOR 222Rn MEASURING DEVICES AND INTER-COMPARISON EXERCISES.

A walk-in type 222Rn calibration chamber of volume 22.7 m3, which has traceability to international standards, is established at the Centre for Advanced Research in Environmental Radioactivity, Mangalore University, India. It has a human-machine interface communication system, a programmable logic controller and sensor feedback circuit for controlling and data acquisition of relative humidity (RH) and temperature (T).