Absorption Life Time of Iodine-131 in Charcoal Filter on the Airborne Measurement in Stack Before Released into the Enviormental

BATAN TECHNOLOGY (BATEK) in Serpong produces Iodine-131 (I-131) routinely for medical needs. Measurements of I-131 airborne in a stack of the BATEK radioisotope installation before being released into the environment has been carried out routinely by using the charcoal filter. Many researchers who do not know the characteristics of the I-13 absorption in charcoal filter were surprised with the results of measurements of I-131. By the time measurement I-131 activity was performed by using gamma spectrometry, the activity of I-131 majority was not detected after a half-life of I-131 (8.04 days). This is due to the absorption life time of I-131 in the charcoal filter. The absorption life time of I-131 is different with half-life time of I-131 in the charcoal filter, because the presence of the absorption life time of I- 131 in the charcoal filter is affected by the flow rate of pump, air temperature and humidity inside the stack. Therefore, research on the absorption life time and absorption efficiency of I-131 in the charcoal filter has been carried out as a function of temperature, flow rate and humidity. The measurement of I-131 absorption efficiency has done on temperature of 30 oC to 45 oC, flow rate of 13 lpm to 26.3 lpm and relative humidity of 30% to 90%. The result showed that the average absorption life time of I-131 in the charcoal filter is 1.497 days. The result of research show that on the temperature performance increase of 30 oC to 45 oC has the absorption efficiency I-131 in charcoal filters increase from 72.4% to 83.3%. The flow rate increases from 13 lpm to 26.3 lpm, so absorption efficiency decreases from 86.6% to 74.8%. The relative humidity increases from 30% to 90%, so absorption efficiency decreases from 88.4% to 67.2%.