Interaction of Sr-90 with site candidate soil for demonstration disposal facility at Serpong

Abstract. Interaction of radiostrontium (Sr-90) with site candidate soil for demonstration disposal facility to be
constructed in the near future at Serpong has been done. This activity is to anticipate the interim storage facility at
Serpong nuclear area becomes full off condition, and show to the public how radioactive waste can be well managed
with the existing technology. To ensure that the location is save, a reliability study of site candidate soil becomes very
importance to be conducted through some experiments consisted some affected parameters such as contact time, effect
of ionic strength, and effect of Sr+ ion in solution. Radiostrontium was used as a tracer on the experiments and has role
as radionuclide reference in low-level radioactive waste due to its long half-live and it’s easy to associate with organism
in nature. So, interaction of radiostrontium and soil samples from site becomes important to be studied. Experiment was
performed in batch method, and soil sample-solution containing radionuclide was mixed in a 20 ml of PE vial. Ratio of
solid: liquid was 10-2 g/ml. Objective of the experiment is to collect the specific characteristics data of radionuclide
sorption onto soil from site candidate. Distribution coefficient value was used as indicator where the amount of initial
and final activities of radiostrontium in solution was compared. Result showed that equilibrium condition was reached
after contact time 10 days with Kd values ranged from 1600-2350 ml/g. Increased in ionic strength in solution made
decreased of Kd value into soil sample due to competition of background salt and radiostrontium into soil samples, and
increased in Sr ion in solution caused decreased of Kd value in soil sample due to limitation of sorption capacity in soil
samples. Fast condition in saturated of metal ion into soil samples was reached due to a simple reaction was occurred.
Keywords: site candidate, soil samples, radiostrontium, sorption, Kd