Hj. Woo et al., Sample treatment techniques for the determination of environmental radiocarbon in a nuclear power station area, J RAD NUCL, 239(3), 1999, pp. 533-538
This report describes the environmental sample treatment techniques for C-1
4 measurement with liquid scintillation counter. The groundwater sample of
about 80 liters was collected from well and inorganic carbon was removed by
acidification and recirculated gas stripping with the extraction efficienc
y of more than 98%. The biological samples were freeze-dried and combusted
to carbon dioxide in high pressure combustion unit with a combustion effici
ency of nearly 99%. The (CO2)-C-14 in the stack effluents was collected by
an air bubbler with a collection efficiency of more than 99% for a sampling
rime of two weeks. Sampling of C-14 in reduced form also has been done by
passing the gases through a tube furnace with Pt/Al and Pd/Al catalyst. Act
ive and passive sampling methods for atmospheric C-14 measurements were com
pared in detail, and it could be concluded that the uncertainty associated
with passive sampling method was quite acceptable for environmental monitor
ing. The CO2 trapped in NaOH was precipitated as BaCO3, and subsequently re
converted to CO2 for environmental samples and transferred to Carbo-Sorb E(
TM) for liquid scintillation counting. In case higher precision is the deci
ding factor, benzene synthesis would be employed with home-made benzene syn
thesizer.