Assessment of the ambient dose rate around research reactors by thermoluminescence dosimeters

Monitoring of radiation levels in and around the nuclear research reactors is essential to safeguarding life and the environment. Background radiation monitoring at the Pakistan Institute of Nuclear Science and Technology (PINSTECH) has been carried out since the early sixties, before the criticality of the 5 MW Pakistan Research Reactor, so as to confirm the safe operation of PINSTECH nuclear facilities. In the present study, ambient dose rate levels were measured around PINSTECH by using TLD-200 (G-2 cards) installed at 15 different locations over a five year period (1998-2002). The mean dose rates for individual locations in the said period ranged from 0.1 0.01 to 0.19 ± 0.03 μSv/h, with a mean value of 0.16 ±0.03 μSv/h. The cumulative average annual effective dose equivalent spread over 5 years was 204.4 ± 17 μSv. The data were compared with the world and averages in other countries. It was concluded that, from the health hazard point of view, the operation of research reactors and other nuclear facilities at PINSTECH presents no risk to public health. (author)