Medical Radiology and Radiation Safety. 2013. Vol. 58. No. 1. P. 29–35
RADIATION PHYSICS, TECHNOLOGY AND DOSIMETRY
V.A. Taranenko1, M.I. Vorobiova1, M.O. Degteva1, N.G. Bougrov1, E.I. Cherepanova2,E.S. Kuropatenko2
Verification of the External Exposure Levels in the Upper Streams of Techa River (Metlino) by Luminescence Measurements
1. Ural Research Center for Radiation Medicine, Chelyabinsk, Russia; 2. Russian Federal Nuclear Center–the All-Russian Scientific and Research Institute of Technical Physics, Snezhinsk, Russia, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Abstract
Purpose: To estimate the external exposure doses in the upper streams of Techa river according to the updated source term and geometry of irradiation; to compare the results with the results of luminescence measurements of building bricks.
Material and methods: The Techa River Dosimetry System, TRDS-2009 has been developed based on archival data of liquid radioactive waste discharges to the Techa river. Major changes in the source term and hydrological data for Metlino settlement located 5–7 km from the point of discharges were taken into account. Estimated levels of external exposure in Metlino can be validated by results of luminescence measurements of irradiated natural quartz contained in building bricks (bricks of the watermill and the granary). Prior reconstruction (TRDS-2000) of the accumulated dose in air at the river shore close to south-west wall of the mill overestimated the results of the luminescence measurements by approx 20 %. This discrepancy has to be explained and taken into account, since the data on accumulated dose in air are used to estimate the external exposure to the river residents.
Results: Based on the improved source term, TRDS-2009 shows insignificant 4 % increase (relative to TRDS-2000) of accumulated in 1949–1956 dose in air at the shore in Metlino and yields 27.7 Gy. The new estimation for external doses due to 137Cs, 95Nb and 95Zr were also carried out. The results of radiation transport modeling for the south-western wall of the mill showed on average 10 % decrease of accumulated dose in air reconstructed from the luminescence dose in comparison with previous estimation. Overall, a better agreement between the TRDS-2009 dose in air and independent luminescence measurements in bricks of Metlino is achieved using the new irradiation geometry and the source term.
Conclusion: As in TRDS-2000, that the results of present validation shows that luminescence measurements do not contradict our knowledge about external exposure in the upper Techa.
Key words: Techa, Mayak, dose reconstruction, external exposure, luminescence dosimetry, Monte Carlo method