Synroc technology developed in Australia is set to deliver an innovative way to reduce the volume of nuclear by-products.
ANSTO is very excited by this Australian technology. ANSTO will use Synroc to treat the by-products of its nuclear medicine production as it can significantly reduce the pre-storage volume of waste when compared to other waste solutions.
What is Synroc?
Synroc technology utilises the study of the behaviour of certain naturally occurring minerals to lock up radioactive elements which have been shown to be durable in the environment over millions of years.
Using a simple concept that copies nature’s way of locking up radioactive elements, the production capabilities of Synroc will help deal with one of our growing global environmental issues in a way that is cost effective and a low risk solution.
Synroc was originally designed for the immobilization of high-level waste (HLW) from the reprocessing of spent nuclear fuel, but today has evolved into a broad family of formulations and associated process technologies with ability to treat a wide range of radioactive wastes.
The expertise of the synroc team at ANSTO lies in tailoring the chemistry of the waste form and the associated process technology to suit the unique characteristics of the waste.
Tailored Synroc designs can offer greatly improved durability. This enables the waste package to effectively lock up the radioactive waste as it decays over tens to hundreds of thousands of years, significantly reducing the long-term environmental risk.
The waste form is the key to the immobilization process. It determines the type of nuclear waste that can be immobilized, the durability of the waste package, and the final waste disposal volume.
What is HIPing?
Hot Isostatic Pressing (HIP) technology consists of a pressure vessel containing a furnace. The components are placed in a sealed stainless steel can inside the furnace which is heated and pressure applied, using argon gas, to create the synthetic rock and minimize disposal volume.
Competitive advantages
The integration of waste form design with Synroc HIP technology achieves great benefits by offering:
- Maximum waste loadings, thus minimizing the waste disposal volume and costs;
- Optimal chemical durability, which reduces environmental risk;
- Increased process flexibility; and
- Lower emissions and secondary wastes.
HIP technology also significantly reduces radioactive emissions during high temperature processing. This simplifies the design and operation of a waste processing plant. Radioactive waste disposal is expensive. Synroc technology with our clients can realize economic savings worth billions of dollars.
Case Study–US
Multi-billion dollar life-cycle cost savings led the US Department of Energy in 2009 to select HIPing as its preferred treatment technology for HLW calcines at the Idaho National Laboratory.
The Synroc team, over many years, has developed and optimized tailored glass-ceramic waste forms and HIP technology explicitly for the treatment of the Idaho HLW calcines.
Production of dense, durable monoliths with extremely high waste loadings (up to 80%) that meet relevant disposal requirements have been demonstrated.
Synroc waste forms can also be applied to the immobilization of a wide range of other legacy radioactive wastes that cannot be economically or technically disposed of using current baseline technologies.
Case Study–UK
Actinide-rich waste streams offer unique immobilization challenges. They typically have very long half-lives; may be fissile, thus requiring criticality control measures; and, depending on their source, can either be very pure or very impure chemically. The Synroc team has developed a range of waste forms for high and low purity actinide waste streams.
ANSTO and the UK National Nuclear Laboratory(NNL) have tailored a unique application of Synroc HIP technology to lock up impure plutonium residues that have been stored for 50 years at Sellafield, without a disposition route. The project team successfully demonstrated that the plutonium residue waste could be safely locked up in a tailored glass-ceramic waste form.
Recognizing the significant reduction in waste liability and improved environmental safety,the UK Nuclear Decommissioning Authority has now selected HIPing as its baseline treatment technology for actinide residues.
Published: 28/09/2012