Hot Isostatic Pressing
NNL provides support to customers in the development of waste immobilisation process and products. There are a number of waste streams which are not suitable for processing using currently established methods, for example cement encapsulation and vitrification.
NNL has been working for a number of years with the Australian Nuclear Science and Technology Organisation (ANSTO) to develop a new immobilisation technology using Hot Isostatic Pressing (HIP) - using high temperature and pressure to create a stable ceramic matrix. A programme funded by Sellafield Limited has successfully demonstrated the immobilisation of plutonium containing wastes and residues in ceramic based wasteforms using this HIP technology.
With the development and demonstration phases largely complete, NNL is now supporting Sellafield Limited in a studies phase as a precursor to the design and build of a pilot plant. The design of this plant will start later this year and the plan is to carry out active demonstration of the technology using actual residues in NNL's Central Laboratory at Sellafield.
The experience gained in the development and demonstration stages has shown there are wider applications for the technology. NNL, with Sellafield Limited's support, is exploring the use of encapsulation using metals such as copper for the immobilisation of other waste streams. Experiments have also shown that other materials such as aluminium, glass and polymers may be suitable candidates for the HIP'ing process and in some cases, acceptable wasteforms can be produced at relatively low temperatures. NNL has utilised its non-active pilot plant, Workington Laboratory, to support this work.