June 10th, 2009

Synroc, a titanate-based ceramic for geological immobilisation of high-level radioactive waste, was invented by Professor Ted Ringwood at the ANU 30 years ago. The basic idea is to incorporate the waste ions in the crystalline lattices of synthetic mineral phases which are known to survive in Nature for millions of years. Since 1979 ANSTO has had an R&D program to study phase assemblages (crystal chemistry), radiation damage effects, aqueous dissolution and processing options. The initial synroc work involved scientific collaborations with national laboratories and nuclear plant operators focusing on high level wastes (HLW) from the reprocessing of spent nuclear power reactor fuel. However in 1995 this was refocussed on problematic nuclear wastes, such as those arising from US defence programs. A major milestone was the downselection by the US Department of Energy in 1998 of a synroc derivative to immobilise surplus impure Pu wastes in the US and Russia. Although actual implementation of this work was not progressed, the synroc program gained considerable kudos worldwide and beginning in 2001 we established ongoing commercial relationships with Nexia Solutions (originally part of BNFL and now the UK National Nuclear Laboratory) on immobilisation of orphan Pu-bearing wastes in the UK.

As part of the Plutonium Immobilisation Project ANSTO set up a company (ANSTO Inc.) in the US as a vehicle to work with US nuclear technology companies to dispose of actual problematic high-level and long-lived nuclear wastes; such as those arising from cold-war defence propulsion and weapons programs. By problematic wastes we mean those wastes for which there was no current disposition route and which cannot be readily incorporated into current baseline technology such as borosilicate glass. This is typically because of technical (due to the chemistry or physical form of the waste, or in the case of Pu-239 criticality control and non proliferation) or economic (typically due to the waste loadings achievable in current baseline routes) reasons. Hence, ANSTO's technology are seen as complementary to existing baseline and the commercial focus aims to enable ANSTO to harvest its intellectual property for reinvestment in scientific R&D; not to mention assisting the world in cleaning up some major nuclear waste challenges.

In 2006 ANSTO Inc. opened an office in Idaho Falls, to promote its wasteform technology in the USA and in particular for use in the disposition of the 4,400m3 of HLW calcine powders located in silos at the Idaho Nuclear Laboratory (INL). ANSTO is currently working on contacts with the US Department of Energy to demonstrate its technology for this application. This includes conceptual engineering designs with its partners. The principal driver in this work is the waste volume reductions and high waste loadings achievable by combining ANSTO's wasteform design technology with appropriate processing technology namely, hot-isostatic pressing. The volume reductions achievable for the INL calcines by using ANSTO's process is estimated to bring $US2-4 billion in disposal cost savings.

We are also looking at the option for using synroc technology to immobilise intermediate-level waste arising from the production of Mo-99 at Lucas Heights and continuing strategic scientific R&D into wastes that may arise from future, Generation IV, type nuclear systems.

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