A good, comprehensive presentation. However, I think that Ahmed is incorrect in his views on a repository. The consequences to the public from a criticality in a closed geological repository would almost certainly be negligible. The repository would be underground 100+m below the surface. This (distance plus shielding by host rock ) would attenuate the radiation dose hugely. Also there would not be sufficient energy from the criticality event to significantly increase pathways for radioactive material to escape to the surface. All-in-all the radiation dose to the public is very unlikely to be of significant concern. For structural reasons the thickness of rock between vaults would be sufficient to reduce radiation doses to operators to levels unlikely to be concern.
