Synroc is composed of three titanate minerals – hollandite, zirconolite and perovskite – plus rutile and a small amount of metal alloy.
Immobilising weapons-grade plutonium or transuranium wastes instead of bulk HLW may essentially change the Synroc phase composition to primarily zirconolite-based or a pyrochlore-based ceramic.
[5] In 1997 Synroc was tested with real HLW using technology developed jointly by ANSTO and the US DoE's Argonne National Laboratory.
[1] In January 2010, the United States Department of Energy selected hot isostatic pressing (HIP) for processing waste at the Idaho National Laboratory.
[7] Synroc was chosen in April 2005 for a multimillion-dollar "demonstration" contract to eliminate 5 t (5.5 short tons) of plutonium-contaminated waste at British Nuclear Fuel's Sellafield plant, on the northwest coast of England.