Published online by Cambridge University Press: 03 September 2012
Synroc-C containing 10wt% simulated PW-4b-D HLW including 0.62 wt% 239Pu wassubjected to MCC-1 type leach tests at 70°C in deionised water, silicate andcarbonate leachates for 53 d and deionised water for 2472 d. The normalisedtotal (i.e. unfiltered leachate + vessel wall) Pu leach rates in deionisedwater, silicate and carbonate leachates for periods up to 53 d were found tobe of the order of 10-5, 10-4 and 10-4 g m-2 d-1 respectively. After 2472 d, thedifferential, normalised, Pu leach rate in deionised water dropped to ∼5 × 10-6 (total) and ∼5 × 10-8 (solution - afterfiltration through a 1000NMW filter) g m-2 d-1. SEMand AEM were used to characterise our starting material and investigate thesecondary phases on the surfaces of leached Synroc-C discs. Calculated andmeasured normalised Pu leach rates are compared and the partitioning of Pubetween zirconolite and perovskite is discussed.