Comparative Analysis of Direct and Indirect I-131 Measurement Methods from the Stack to Outdoor

The radioisotope production facility at PUSPIPTEK Serpong produces and
processes 131I that can disperse to the settlements (community) and the environment
around the Serpong Nuclear Area (SNA). 131I is produced routinely for medical
uses in hospitals and pharmacies, for both domestic uses and export. 131I is a beta
and gamma emitting radioactive material and can cause thyroid cancer.
The problem was that there was so far no research and in-depth assessment of the
aerial dispersion of 131I radioactivity emitted from the radioisotope production stack
to the environment at actual conditions. The research was conducted through
simultaneous measurement of 131I radioactivity in the stack of the 131I radioisotope
production facility, Serpong, and outdoor in house courtyards around SNA in
normal condition (no accident) based on the variations of the distance and wind
direction. Direct measurements were carried out with a portable in-situ NaI(Tl)
detector at outdoor, and with a LaBr3 detector in the stack. Indirect measurements
were carried out by using charcoal filter and vacuum pump in the stack and
outdoor. The direct measurement method has many advantages over the indirect
measurement. The direct measurement method was found to be more accurate, less
expensive, easier to operate, needing just one operator in its implementation,
portable, and can be operated continuously and for long durations. The overall
activity concentrations of 131I on average obtained by either direct or indirect
method were still below the upper limit of 131I activity concentration in the air
(530 Bq/m3
) stipulated by the Regulation of the Chairman of BAPETEN (Perka
BAPETEN) No. 7/2013.