http://www.world-nuclear.org/info/Country-Profiles/Countries...
In Commonwealth government documents, low-level wastes are 'category A', short-lived Intermediate Level Waste are 'category B' if amenable to *embedding in concrete* prior to disposal...

http://nuclearinfo.net/Nuclearpower/WebHomeWasteFromNuclearP...
"The solidification of nuclear waste ...consists of dispersal in a glass matrix. However, alternative techniques are being researched. One such technique consists of embedding the waste into a ceramic matrix..."

http://www.springerimages.com/Images/RSS/1-10.1007_978-0-387...
Fig 41 Industrial implementation of waste cementation (embedding of solid waste)