Safe waste storage

Thanks to a team of Queensland University of Technology academics, radioactive waste may no longer be dangerous to store.

The team, led by associate professor Zhu Huai Yong from the School of Physical and Chemical Sciences, has created a material that has the potential to filter and safely lock away radioactive ions from waste water.

Zhu said effective measures to prevent radioactive contamination of the environment are greatly needed, as the world increases its reliance on nuclear energy.

He said: ‘Water is used to cool nuclear reactors and during the mining and purification of nuclear material, so waste water is a big problem. For example, there is a lake in the US filled with millions of gallons of nuclear waste water. However, if waste is stored conventionally in lakes or steel containers, it may leak and pollute the land around it.’

Zhu said the team has discovered how to create nanofibres that are millionths of a millimetre in size and could permanently lock away radioactive cations by displacing the existing sodium ions in the fibre.

He added: ‘The ceramic material can last a very long time, much longer than the radioactivity of a radioactive ion. The material is more chemically stable than metal and can last much longer, and therefore can be a better material for storage. It’s also much cheaper to make than steel.’

Zhu said the ceramic nanofibres were made from titanium dioxide, a mineral found abundantly in Australia and used to colour white paint, which is mixed with caustic soda and heated in a laboratory oven.

The fibres are in very thin layers, less than one nanometre in width, and the radioactive ions are attracted into the space between the layers. Once the ceramic material absorbs a certain amount, the layers collapse to lock the radioactive ions inside.