A decade of radiological monitoring at beach sand mineral separation plant Chavara

The predominant industrial process which require handling of Naturally Occurring Radioactive Materials (NORM) are processing of Beach Sand Minerals (BSM).The Chavara Mineral Division of IREL (India) Ltd is situated in the south west coast of Kerala (8.98210 N & 76.52600 E) within the Natural High Background Area of Kerala, India. Regulatory mandate to perform continuous radiological monitoring of occupational workers in such a front end nuclear fuel cycle facility is the responsibility of Health Physics Unit under HPD, BARC. The maximum individual dose recorded in a year varied from 1.37 mSv (in 2012) to 4.77 mSv (in 2014), which is <25% of the annual dose limit. IAEA-SRS.49, 2006 says that the available data from BSM/Monazite based industry suggest that the average dose received by a worker is in the range of 1–8 mSv/annum, with higher exposures being possible where controls are inadequate. Contribution of internal dose in total individual dose, due to short-lived Thoron progenies and long-lived ²³²Th, is found to be varying from 17% to 53% with an average of 34±10%. The average internal dose varied from 0.086 to 0.24 mSv with an average of 0.13±0.05 mSv per annum. The occupational dose records in the period of 2012-2021 implies, IREL Chavara is consistent to implement ideal levels of occupational dose control practices, engineering safety measures and effective worker-management coordinations to maintain the occupational dose below the industry average