Monitoring of Kr-85 by using BfS-IAR System

In this study, the atmospheric ⁸⁵Kr concentration of the west of South Korea was measured using the BfS-IAR system. To analyze the atmospheric ⁸⁵Kr concentration with a high level of accuracy, the trapped amount of 85Kr using by an adsorption module (⁸⁵Kr sampling module) is very important. One of effective methods to increase the amount of trapped ⁸⁵Kr is to design the optimum structure of the module. The adsorption/desorption dead zone in the module should be removed to increase the amount of trapped ⁸⁵Kr. We got the distribution data of pressure, air velocity and temperature in adsorption modules of three cases to investigate the dead zone using a simulation software. In conclusion, the mean activity concentration of ⁸⁵Kr in the area of the west of South Korea was obtained (ca. 1.53 Bq/m3) by using the BfS-IAR system. It required a lot of manpower because all stages to get data should be performed manually although reliable data with a high level of accuracy were obtained by using the system. The baffles in the module played an important role for the heat transfer and mass transfer while cone-type of the module bottom did not show meaningful results in the mass transfer analysis.