Measurement of .sup.3H, .sup.36Cl, .sup.22Na, .sup.85Sr and .sup.133Ba activities from synthetic groundwater

Radioactive elements (.sup.3H, .sup.36Cl, .sup.22Na, .sup.85Sr and .sup.133Ba) was used and measured in one of the in-situ experiments. The separation scheme had to be developed and optimized. .sup.36Cl was first extracted by silver chloride precipitation and then .sup.85Sr and .sup.133Ba were extracted by Sr/Ba carbonate precipitation after which activities of .sup.3H and .sup.36Cl were measured by liquid scintillation counting while activities of gamma emitters (.sup.22Na, .sup.85Sr and .sup.133Ba) were measured by gamma spectrometry from the initial solution. In the precipitation, the recoveries of .sup.36Cl and .sup.85Sr were 100 % while the recovery of .sup.133Ba was about 85 %. The detection limit of .sup.3H was 0.1 Bq g.sup.-1 whereas the detection limit of .sup.36Cl was 0.05 Bq g.sup.-1.