Automated separation and analysis of krypton-85 from low-volume gaseous effluent of nuclear power plant

摘要

Based on the requirements of the lower detection limit for the low-volume gaseous effluent, we have designed an automatic separation apparatus of krypton (Kr). The principle of the apparatus is based on both the adsorption and desorption mechanism in the traps with the activated carbon particles and gas chromatography with 5A molecular sieves. The separation efficiency and overall recovery rate could be maintained at about (90.4 +/- 4.2)% and (24.3 +/- 1.3)%. The Kr-85 could be radioassayed on a liquid scintillation counter following the automatic separation and loading into the cryogenic count vial. The detection limit based the low-volume of 3 L is about 9.5 Bq m(-3), and the expanded relative uncertainties are in the range of 13-18% for typical measurements.