Fabication and properties of SYNROC

The first SYNROC fabrication method chosen for a scale-up demonstration at the AAEC was in-can hot pressing. Two other methods, the hot pressing of SYNROC in unsupported thin-walled bellows and a hybrid method using bellows-type cans within a canister which could be unsupported during hot pressing are being compared with the original concept. Attention has been given to the evolution of a simplified process for SYNROC C powder preparation involving flash drying, denitration and calcination in a rotary calciner. Leach tests show that SYNROC is more leach resistant than borosilicate glasses over the temperature range 45-300 deg. C, that the SYNROC leach rate does not increase greatly with temperature and decreases rapidly with time and that caesium is the most leachable HLW element