How radioactive material that could be released to the water table would move south to southeast of the repository and eventually reach a well used for a small farming and residential community. The TSPA will forecast out to 10,000 years. In the expected situation, the repository is not significantly disturbed by either human or natural forces and performs according to design. So the TSPA will project the probable behavior and effects of these high-consequence, but unlikely, events. Finally, a separate TSPA must assess what would happen if a human drilled completely through a waste package while exploring for water 100 years after the repository is permanently closed.
Scientists can, however, observe and analyze the results of laboratory and field experiments.
They can then compare those observed results with the results projected by the computer calculations and, through the TSPA, gain confidence about the repository's likely performance. Features are physical, chemical, and thermal characteristics of the total repository system - and how they work over time. The rock's structure and hardness, and the way they could respond to heat given off by radionuclide decay, are examples of repository features. Events are occurrences that have a specific starting time and are usually of short duration - an earthquake, for example. Processes are activities that have gradual but continuous interactions with the overall repository system - for instance, water moving through the mountain.