Analysis of collective external dose difference between TLD and DRD in Kaiga generating station during the year 2005

Thermo luminescent Dosimeter (TLD) is used for Personnel monitoring and Direct Reading Dosimeter (DRD) is used for daily dose control of individual radiation workers. The difference in monthly dose recorded by TLD and DRD for an individual at Kaiga Generating Station was insignificant except during Biennial shut down (BSD), July 2005. However, the findings on cause for low-level difference cases resulted in useful information in support of Station man-Rem reduction. Collective dose in a month recorded by TLD was about 10 Person-mSv higher than DRD during normal operation. This paper elucidates the reason for difference of individual TLD and DRD doses and the various measures to be implemented to minimize the same. (author)