A simple and reliable monitoring system for 3H and 14C in radioactive airborne effluent

A simple and reliable sampling system for H-3 and C-14 in airborne release from nuclear facilities was designed. The sampling system can collect H-3 and C-14 simultaneously with a condensation technique using a commercially available cold trap equipment and a CO, absorption technique using an organic alkali monoethanolamine solution, respectively. In situ performance tests for the effluent from a reprocessing plant showed that the system has high and stable efficiencies for collecting H-3 and C-14 for a one-week batch sampling at a sampting flow rate of 0.4 l(.)min(-1). These collection techniques also provided a simple procedure of following sample preparation for activity measurements by liquid scintillation counting. The detectable concentrations of the proposed monitoring method were 3.0 Bq(.)m(-3) for H-3 and 1.6 Bq(.)m(-3) for C-14, respectively. The sensitivity would be on an acceptable level for routine monitoring of airborne release at nuclear facilities.