Prediction of near-field fluid composition in high-level nuclear waste repositories

Fluids from active geothermal fields and hydrothermal experiments have been used to predict the composition of groundwaters passing through a high-level nuclear waste repository. Predictions from both analogs are similar over most of the temperature range. This suggests that possible deficiencies in the experiments (short duration) and geothermal fields (composition differences from proposed repositories) do not invalidate their use as analogs. Differences in fluid composition parameters found at high temperatures (>250 degrees C) appear largely due to magmatic gas inputs into the geothermal fluids