Other parameters were fixed.
The exposure time considered for workers was 50 years, the maximum time that a worker would be exposed to the radioactive content in NORM wastes.
On the other side it was considered around a thousand years for the assessment to the public, as some processes as erosion of the cover or leaching to the ground water, will become important after some hundreds of years.
After that period it is considered that control would disappear and any prediction would become use-less.
The only protection which can be considered plausible after that loss of control is that any human intrusion would detect the existence of wastes, which will be analyzed in order to detect any
chemical or radioactive toxicity