Fissure elution experiments

Fissure Elution Experiments. The migration characteristics of americium by water transport in fissures fabricated from gray hornblende schist were determined. Fissures not used in the previous sorption experiments were used for these elution experiments. A diagram of the experimental apparatus is shown in Figure 4. Solution reservoirs were attached above the fissures and the small bore tubes affixed to the bottom of the fissures were connected to solution metering pumps. 

Before the elution experiments were performed, the "schist"-equilibrated water was pumped through the fissures for two days to allow the fissure walls to interact with the rock-equilibrated water. 

Figure 4. Diagram of apparatus used for fissure elution experiments...

The second set of fissure-elution experiments was performed in the same manner as described for the first set of fissure-elution experiments. The difference in the second set of experiments was that after 0.67 fissure volumes of stock solution were drawn into the fissures at their respective flow rates, the stock solution in the reservoirs was replaced with rock-equilibrated water. The solution metering pumps were not turned off during the exchange. Subsequently, a total of twenty fissure volumes of solution was drawn through each fissure before the metering pumps were turned off. After the metering pumps were stopped, the rock-equilibrated water was removed from the reservoirs and the solution in the fissures was rapidly drawn off. 

The plutonium, in this case the a-emitting tJOPu, was introduced at the top of the fissure in a very small volume (about 50 yl) by means of an infusion pump. The subsequent elution of the adsorbed plutonium from the surface of the basalt also made use of the Infusion pump. Water was the elution medium, and, since the pump was constructed to deliver predetermined volumes at a slow, steady rate, it was well suited for this kind of experiment. 

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