High level and long lived intermediate level radioactive wastes require special handling and disposal because of the high level of ongoing activity within them.

Special casks are designed to contain and store these materials on site where they are produced during their cooling off period, which is normally between 20 and 50 years.

Following this, the material can then be transported to final disposal sites in specially designed transport casks.

High density (heavyweight) concrete is utilized in these casks because its versatility allows for customization of mixes to meet these specifications.