The LS regression models for geological
units with high permeability, analogous to the disturbed ground of the repository wastes and
capping materials, predict higher levels of indoor radon for a specific estimated 226Ra concentrations
in the ground or soil gas radon concentrations than regression models for generally impermeable
geological units. That being the case, it would be appropriate to use the models for the high
permeability units in post-closure assessments of radon related to the radioactive waste in the LLWR
as this will tend to be cautious.