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

Abstract

Monitoring of radiation levels in and around the nuclear research reactors is essential to safe-guarding life and the environment. Background radiation monitoring at the Pakistan Institute of Nuclear Science & 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 0.14 ± 0.01 to 0.19 ± 0.03 µSv/h, with a mean value of 0.16 ± 0.03 µSv/h. The cu- mulative 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.

Keywords

• environmental radiation
• ambient dose rate
• annual effective doses
• seasonal variation
• research reactors
• thermoluminescence dosimeter