Subsurface Nuclear Storage
the Basics of Subsurface Nuclear StorageAlthough not really petroleum related I still had this short essay on subsurface nuclear storage; Comments are welcome!
Subsurface storage is becoming increasingly popular, because of it’s large capacity, long-term potential and economic feasibility. In the past process of disposing or storing material underground was primarily targeted towards toxic waste and radioactive material. Salt formations provided excellent storage rocks as salt can be easily mined, it’s highly impermeable character and it’s ability to refill and seal caverns due to it’s high creep rate.
The research in this area focused on the effect of radioactive radiation on salt crystals, the effects of the heating of the rock and on finding crystal-lattices that could hold radioactive atoms. Some important discoveries have been made. For example, the hot radioactive waste causes brine cavities to migrate towards the waste along the geotherm because of more salt dissolving at the warm side of a cavity, precipitating at the colder side. This may cause relatively dry salt formations to attract water, increasing the danger of ‘radioactive’ water escaping. Another important finding was that radiation caused brittleness in salt crystals. The altered crystal structures were quickly replaced due to salt high creep rate (grain boundary migration), but the brittle rock could cause faults an fissures that provide pathways for escaping water. This is of course very dangerous when one considers the implications of radio-active material flowing to the surface.