Radon as a natural tracer for gas transport within uranium waste rock piles.

Authors :: Silva NC
Chagas EG
Abreu CB
Dias DC
Lopez D
Guerreiro ET
Alberti HL
Braz ML
Branco O
Fleming P
Source :: Radiation protection dosimetry [Radiat Prot Dosimetry] 2014 Jul; Vol. 160 (1-3), pp. 74-7. Date of Electronic Publication: 2014 Apr 11.
Publication Year :: 2014
Abstract: Acid mine drainage (AMD) has been identified as the main cause for outflow of acid water and radioactive/non-radioactive contaminants. AMD encompasses pyrites oxidation when water and oxygen are available. AMD was identified in uranium waste rock piles (WRPs) of Indústrias Nucleares do Brasil-Caldas facility (Brazilian uranium mine), resulting in high costs for water treatment. AMD reduction is the main challenge, and scientific investigation has been conducted to understand oxygen and water transportation within WRPs, where 222Rn is used as natural tracer for oxygen transportation. The study consists of soil radon gas mapping in the top layer of WRP4 using active soil gas pumping, radon adsorption in active charcoal and 222Rn determination using high-resolution gamma-ray spectrometry. A sampling network of 71 points was built where samples were collected at a depth of 40 cm. Soil radon gas concentration ranged from 33.7 to 1484.2 kBq m(-3) with mean concentration of 320.7±263.3 kBq m(-3).<br /> (© The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)