Indigenous Passive Personal Radon (222Rn) Dosimeter for Use in Uranium Mines of India

Underground uranium mines, in particular, is associated with radiological conditions normally not anticipated in other mining industries. Depending on the grade and characteristics of the uranium deposit, the radiological hazard considerations may widely vary. Although short lived radon progeny are the major contributor of individual dose to the miners, dose assessment using their activity concentration data is normally avoided. Mine dust, diesel fumes, high humidity and seepage from the surrounding surface poses additional difficulty in direct estimation of radon progeny activity concentration. Individual doses are computed through radon (²²²Rn) monitoring data and equilibrium ratio (F) between radon and its short lived progeny. Both ambient and passive techniques are used in Indian uranium mines for the dose assessment but the passive technique is preferred over the ambient as the later can explicitly account the individual worker during its uses. The device, Personal Radon Dosimeter (PRD), based on nuclear track registry on a LR-115 Kotak film has indigenously been designed after detailed scientific studies. Basic features of this device, their uses, track registry and calibration aspects along with dose assessment methodology of uranium miners are provided in the paper.